Feeds:
Posts
Comments

Posts Tagged ‘immune system’

 

Abstract:

The immune response mechanism is the holy grail of the human defense system for health.   IDO, indolamine 2, 3-dioxygenase, is a key gene for homeostasis of immune responses and producing an enzyme catabolizing the first rate-limiting step in tryptophan degradation metabolism. The hemostasis of immune system is complicated.  In this review, the  properties of IDO such as basic molecular genetics, biochemistry and genesis will be discussed.

IDO belongs to globin gene family to carry oxygen and heme.  The main function and genesis of IDO comes from the immune responses during host-microbial invasion and choice between tolerance and immunegenity.  In human there are three kinds of IDOs, which are IDO1, IDO2, and TDO, with distinguished mechanisms and expression profiles. , IDO mechanism includes three distinguished pathways: enzymatic acts through IFNgamma, non-enzymatic acts through TGFbeta-IFNalpha/IFNbeta and moonlighting acts through AhR/Kyn.

The well understood functional genomics and mechanisms is important to translate basic science for clinical interventions of human health needs. In conclusion, overall purpose is to find a method to manipulate IDO to correct/fix/modulate immune responses for clinical applications.

The first part of the review concerns the basic science information gained overall several years that lay the foundation where translational research scientist should familiar to develop a new technology for clinic. The first connection of IDO and human health came from a very natural event that is protection of pregnancy in human. The focus of the translational medicine is treatment of cancer or prevention/delay cancer by stem cell based Dendritic Cell Vaccine (DCvax) development.

Table of Contents:

  • Abstract

1         Introduction: IDO gene encodes a heme enzyme

2        Location, location, location

3        Molecular genetics

4        Types of IDO:

4.1       IDO1,

4.2       IDO2,

4.3       IDO-like proteins

5        Working mechanisms of IDO

6        Infection Diseases and IDO

7. Conclusion

  1. 1.     Indoleamine 2, 3-dioxygenase (IDO) gene encodes a heme enzyme

IDO is a key homeostatic regulator and confined in immune system mechanism for the balance between tolerance and immunity.  This gene encodes indoleamine 2, 3-dioxygenase (IDO) – a heme enzyme (EC=1.13.11.52) that catalyzes the first rate-limiting step in tryptophan catabolism to N-formyl-kynurenine and acts on multiple tryptophan substrates including D-tryptophan, L-tryptophan, 5-hydroxy-tryptophan, tryptamine, and serotonin.

The basic genetic information describes indoleamine 2, 3-dioxygenase 1 (IDO1, IDO, INDO) as an enzyme located at Chromosome 8p12-p11 (5; 6) that active at the first step of the Tryptophan catabolism.    The cloned gene structure showed that IDO contains 10 exons ad 9 introns (7; 8) producing 9 transcripts.

After alternative splicing only five of the transcripts encode a protein but the other four does not make protein products, three of transcripts retain intron and one of them create a nonsense code (7).  Based on IDO related studies 15 phenotypes of IDO is identified, of which, twelve in cancer tumor models of lung, kidney, endometrium, intestine, two in nervous system, and one HGMD- deletion.

  1. 2.     Location, Location and Location

The specific cellular location of IDO is in cytosol, smooth muscle contractile fibers and stereocilium bundle. The expression specificity shows that IDO is present very widely in all cell types but there is an elevation of expression in placenta, pancreas, pancreas islets, including dendritic cells (DCs) according to gene atlas of transcriptome (9).  Expression of IDO is common in antigen presenting cells (APCs), monocytes (MO), macrophages (MQs), DCs, T-cells, and some B-cells. IDO present in APCs (10; 11), due to magnitude of role play hierarchy and level of expression DCs are the better choice but including MOs during establishment of three DC cell subset, CD14+CD25+, CD14++CD25+ and CD14+CD25++ may increase the longevity and efficacy of the interventions.

IDO is strictly regulated and confined to immune system with diverse functions based on either positive or negative stimulations. The positive stimulations are T cell tolerance induction, apoptotic process, and chronic inflammatory response, type 2 immune response, interleukin-12 production (12).  The negative stimulations are interleukin-10 production, activated T cell proliferation, T cell apoptotic process.  Furthermore, there are more functions allocating fetus during female pregnancy; changing behavior, responding to lipopolysaccharide or multicellular organismal response to stress possible due to degradation of tryptophan, kynurenic acid biosynthetic process, cellular nitrogen compound metabolic process, small molecule metabolic process, producing kynurenine process (13; 14; 15).

IDO plays a role in a variety of pathophysiological processes such as antimicrobial and antitumor defense, neuropathology, immunoregulation, and antioxidant activity (16; 17; 18; 19).

 

 3.     Molecular Genetics of IDO:

A: Structure of human IDO2 gene and transcripts. Complete coding region is 1260 bps encoding a 420 aa polypeptide. Alternate splice isoforms lacking the exons indicated are noted. Hatch boxes represent a frameshift in the coding region to an alternate reading frame leading to termination. Black boxes represent 3' untranslated regions. Nucleotide numbers, intron sizes, and positioning are based on IDO sequence files NW_923907.1 and GI:89028628 in the Genbank database. (reference: http://atlasgeneticsoncology.org/Genes/IDO2ID44387ch8p11.html)

A: Structure of human IDO2 gene and transcripts. Complete coding region is 1260 bps encoding a 420 aa polypeptide. Alternate splice isoforms lacking the exons indicated are noted. Hatch boxes represent a frameshift in the coding region to an alternate reading frame leading to termination. Black boxes represent 3′ untranslated regions. Nucleotide numbers, intron sizes, and positioning are based on IDO sequence files NW_923907.1 and GI:89028628 in the Genbank database.
(reference: http://atlasgeneticsoncology.org/Genes/IDO2ID44387ch8p11.html)

Molecular genetics data from earlier findings based on reporter assay results showed that IDO promoter is regulated by ISRE-like elements and GAS-sequence at -1126 and -1083 region (20).  Two cis-acting elements are ISRE1 (interferon sequence response element 1) and interferon sequence response element 2 (ISRE2).

Analyses of site directed and deletion mutation with transfected cells demonstrated that introduction of point mutations at these elements decreases the IDO expression. Removing ISRE1 decreases the effects of IFNgamma induction 50 fold and deleting ISRE1 at -1126 reduced by 25 fold (3). Introducing point mutations in conserved t residues at -1124 and -1122 (from T to C or G) in ISRE consensus sequence NAGtttCA/tntttNCC of IFNa/b inducible gene ISG4 eliminates the promoter activity by 24 fold (21).

ISRE2 have two boxes, X box (-114/1104) and Y Box 9-144/-135), which are essential part of the IFNgamma response region of major histocompatibility complex class II promoters (22; 23).  When these were removed from ISRE2 or introducing point mutations at two A residues of ISRE2 at -111 showed a sharp decrease after IFNgamma treatment by 4 fold (3).

The lack of responses related to truncated or deleted IRF-1 interactions whereas IRF-2, Jak2 and STAT91 levels were similar in the cells, HEPg2 and ME180 (3). Furthermore, 748 bp deleted between these elements did not affect the IDO expression, thus the distance between ISRE1 and ISRE2 elements have no function or influence on IDO (3; 24)

B: Amino acid alignment of IDO and IDO2. Amino acids determined by mutagenesis and the crystal structure of IDO that are critical for catalytic activity are positioned below the human IDO sequence. Two commonly occurring SNPs identified in the coding region of human IDO2 are shown above the sequence which alter a critical amino acid (R248W) or introduce a premature termination codon (Y359stop).

B: Amino acid alignment of IDO and IDO2. Amino acids determined by mutagenesis and the crystal structure of IDO that are critical for catalytic activity are positioned below the human IDO sequence. Two commonly occurring SNPs identified in the coding region of human IDO2 are shown above the sequence which alter a critical amino acid (R248W) or introduce a premature termination codon (Y359stop).

4.     There are three types of IDO in human genome:

IDO was originally discovered in 1967 in rabbit intestine (25). Later, in 1990 the human IDO gene is cloned and sequenced (7).  However, its importance and relevance in immunology was not created until prevention of allocation of fetal rejection and founding expression in wide range of human cancers (26; 27).

There are three types of IDO, pro-IDO like, IDO1, and IDO2.  In addition, another enzyme called TDO, tryptophan 2, 3, dehydrogenase solely degrade L-Trp at first-rate limiting mechanism in liver and brain.

4.1.  IDO1:

IDO1 mechanism is the target for immunotherapy applications. The initial discovery of IDO in human physiology is protection of pregnancy (1) since lack of IDO results in premature recurrent abortion (28; 26; 29).   The initial rate-limiting step of tryptophan metabolism is catalyzed by either IDO or tryptophan 2, 3-dioxygenase (TDO).

Structural studies of IDO versus TDO presenting active site environments, conserved Arg 117 and Tyr113, found both in TDO and IDO for the Tyr-Glu motif, but His55 in TDO replaced by Ser167b in IDO (30; 2). As a result, they are regulated with different mechanisms (1; 2) (30).  The short-lived TDO, about 2h, responds to level of tryptophan and its expression regulated by glucorticoids (31; 32).  Thus, it is a useful target for regulation and induced by tryptophan so that increasing tryptophan induces NAD biosynthesis. Whereas, IDO is not activated by the level of Trp presence but inflammatory agents with its interferon stimulated response elements (ISRE1 and ISRE2) in its (33; 34; 35; 36; 3; 10) promoter.

TDO promoter contains glucorticoid response elements (37; 38) and regulated by glucocorticoids and other available amino acids for gluconeogenesis. This is how IDO binds to only immune response cells and TDO relates to NAD biosynthesis mechanisms. Furthermore, TDO is express solely in liver and brain (36).  NAD synthesis (39) showed increased IDO ubiquitous and TDO in liver and causing NAD level increase in rat with neuronal degeneration (40; 41).  NAM has protective function in beta-cells could be used to cure Type1 diabetes (40; 42; 43). In addition, knowledge on NADH/NAD, Kyn/Trp or Trp/Kyn ratios as well as Th1/Th2, CD4/CD8 or Th17/Threg are equally important (44; 40).

Active site of IDO–PI complex. (A) Stereoview of the residues around the heme of IDO viewed from the side of heme plane. The proximal ligand H346 is H-bonded to wa1. The 6-propionate of the heme contacts with wa2 and R343 Nε. The wa2 is H-bonded to wa1, L388 O, and 6-propionate. Mutations of F226, F227, and R231 do not lose the substrate affinity but produce the inactive enzyme. Two CHES molecules are bound in the distal pocket. The cyclohexan ring of CHES-1 (green) contacts with F226 and R231. The 7-propionate of the heme interacts with the amino group of CHES-1 and side chain of Ser-263. The mutational analyses for these distal residues are shown in Table 1. (B) Top view of A by a rotation of 90°. The proximal residues are omitted. (http://www.pnas.org/content/103/8/2611/F3.expansion.html)

Active site of IDO–PI complex. (A) Stereoview of the residues around the heme of IDO viewed from the side of heme plane. The proximal ligand H346 is H-bonded to wa1. The 6-propionate of the heme contacts with wa2 and R343 Nε. The wa2 is H-bonded to wa1, L388 O, and 6-propionate. Mutations of F226, F227, and R231 do not lose the substrate affinity but produce the inactive enzyme. Two CHES molecules are bound in the distal pocket. The cyclohexan ring of CHES-1 (green) contacts with F226 and R231. The 7-propionate of the heme interacts with the amino group of CHES-1 and side chain of Ser-263. The mutational analyses for these distal residues are shown in Table 1. (B) Top view of A by a rotation of 90°. The proximal residues are omitted. (http://www.pnas.org/content/103/8/2611/F3.expansion.html)

4.2. IDO2:

The third type of IDO, called IDO2 exists in lower vertebrates like chicken, fish and frogs (45) and in human with differential expression properties. The expression of IDO2 is only in DCs, unlike IDO1 expresses on both tumors and DCs in human tissues.  Yet, in lower invertebrates IDO2 is not inhibited by general inhibitor of IDO, D-1-methyl-tryptophan (1MT) (46).   Recently, two structurally unusual natural inhibitors of IDO molecules, EXIGUAMINES A and B, are synthesized (47).  LIP mechanism cannot be switch back to activation after its induction in IDO2 (46).

Crucial cancer progression can continue with production of IL6, IL10 and TGF-beta1 to help invasion and metastasis.  Inclusion of two common SNPs affects the function of IDO2 in certain populations.  SNP1 reduces 90% of IDO2 catalytic activity in 50% of European and Asian descent and SNP2 produce premature protein through inclusion of stop-codon in 25% of African descent lack functional IDO2 (Uniport).

4.3. IDO-like proteins: The Origin of IDO:

Knowing the evolutionary steps will helps us to identify how we can manage the regulator function to protect human health in cancer, immune disorders, diabetes, and infectious diseases.

Bacterial IDO has two types of IDOs that are group I and group II IDO (48).  These are the earliest version of the IDO, pro-IDO like, proteins with a quite complicated function.  Each microorganism recognized by a specific set of receptors, called Toll-Like Receptors (TLR), to activate the IDO-like protein expression based on the origin of the bacteria or virus (49; 35).   Thus, the genesis of human IDO originates from gene duplication of these early bacterial versions of IDO-like proteins after their invasion interactions with human host.  IDO1 only exists in mammals and fungi.

Fungi also has three types of IDO; IDOa, IDO beta, and IDO gamma (50) with different properties than human IDOs, perhaps multiple IDO is necessary for the world’s decomposers.

All globins, haemoglobins and myoglobins are destined to evolve from a common ancestor, which  is only 14-16kDa (51) length. Binding of a heme and being oxygen carrier are central to the enzyme mechanism of this family.  Globins are classified under three distinct origins; a universal globin, a compact globin, and IDO-like globin (52) IDO like globin widely distributed among gastropodic mollusks (53; 51).  The indoleamine 2, 3-dioxygenase 1–like “myoglobin” (Myb) was discovered in 1989 in the buccal mass of the abalone Sulculus diversicolor (54).

The conserved region between Myb and IDO-like Myb existed for at least 600 million years (53) Even though the splice junction of seven introns was kept intact, the overall homolog region between Myb and IDO is only about 35%.

No significant evolutionary relationship is found between them after their amino acid sequence of each exon is compared to usual globin sequences. This led the hint that molluscan IDO-like protein must have other functions besides carrying oxygen, like myoglobin.   Alignment of S. cerevisiae cDNA, mollusk and vertebrate IDO–like globins show the key regions for controlling IDO or myoglobin function (55). These data suggest that there is an alternative pathways of myoglobin evolution.  In addition, understanding the diversity of globin may help to design better protocols for interventions of diseases.

Mechanisms of IDO:

The dichotomy of IDO mechanism lead the discovery that IDO is more than an enzyme as a versatile regulator of innate and adaptive immune responses in DCs (66; 67; 68). Meantime IDO also involve with Th2 response and B cell mediated autoimmunity showing that it has three paths, short term (acute) based on enzymatic actions, long term (chronic) based on non-enzymatic role, and moonlighting relies of downstream metabolites of tryptophan metabolism (69; 70).

IFNgamma produced by DC, MQ, NK, NKT, CD4+ T cells and CD8+ T cells, after stimulation with IL12 and IL8.  Inflammatory cytokine(s) expressed by DCs produce IFNgamma to stimulate IDO’s enzymatic reactions in acute response.  Then, TDO in liver and tryptophan catabolites act through Aryl hydrocarbon receptor induction for prevention of T cell proliferation. This mechanism is common among IDO, IDO2 (expresses in brain and liver) and TDO expresses in liver) provide an acute response for an innate immunity (30). When the pDCs are stimulated with IFNgamma, activation of IDO is go through Jak, STAT signaling pathway to degrade Trp to Kyn causing Trp depletion. The starvation of tryptophan in microenvironment inhibits generation of T cells by un-read t-RNAs and induce apoptosis through myc pathway.  In sum, lack of tryptophan halts T cell proliferation and put the T cells in apoptosis at S1 phase of cell division (71; 62).

The intermediary enzymes, functioning during Tryptophan degradation in Kynurenine (Kyn) pathway like kynurenine 3-hydroxylase and kynureninase, are also induced after stimulation with liposaccaride and proinflammatory cytokines (72). They exhibit their function in homeostasis through aryl-hydrocarbon receptor (AhR) induction by kynurenine as an endogenous signal (73; 74).  The endogenous tumor-promoting ligand of AhR are usually activated by environmental stress or xenobiotic toxic chemicals in several cellular processes like tumorigenesis, inflammation, transformation, and embryogenesis (Opitz ET. Al, 2011).

Human tumor cells constitutively produce TDO also contributes to production of Kyn as an endogenous ligand of the AhR (75; 27).  Degradation of tryptophan by IDO1/2 in tumors and tumor-draining lymph nodes occur. As a result, there are animal studies and Phase I/II clinical trials to inhibit the IDO1/2 to prevent cancer and poor prognosis (NewLink Genetics Corp. NCT00739609, 2007).

 IDO mechanism for immune response

Systemic inflammation (like in sepsis, cerebral malaria and brain tumor) creates hypotension and IDO expression has the central role on vascular tone control (63).  Moreover, inflammation activates the endothelial coagulation activation system causing coagulopathies on patients.  This reaction is namely endothelial cell activation of IDO by IFNgamma inducing Trp to Kyn conversion. After infection with malaria the blood vessel tone has decreases, inflammation induce IDO expression in endothelial cells producing Kyn causing decreased trp, lower arterial relaxation, and develop hypotension (Wang, Y. et. al 2010).  Furthermore, existing hypotension in knock out Ido mice point out a secondary mechanism driven by Kyn as an endogenous ligand to activate non-canonical NfKB pathway (63).

Another study also hints this “back –up” mechanism by a significant outcome with a differential response in pDCs against IMT treatment.  Unlike IFN gamma conditioned pDC blocks T cell proliferation and apoptosis, methyl tryptophan fails to inhibit IDO activity for activating naïve T cells to make Tregs at TGF-b1 conditioned pDCs (77; 78).

 Indoleamine-Pyrrole 2,3,-Dioxygenase; IDO dioxygenase; Indeolamine-2,3

The second role of the IDO relies on non-enzymatic action as being a signal molecule. Yet, IDO2 and TDO are devoid of this function. This role mainly for maintenance of microenvironment condition. DCs response to TGFbeta-1 exposure starts the kinase Fyn induce phosphorylation of IDO-associated immunoreceptor tyrosine–based inhibitory motifs (ITIMs) for propagation of the downstream signals involving non-canonical (anti-inflammatory) NF-kB pathway for a long term response. When the pDCs are conditioned with TGF-beta1 the signaling (68; 77; 78) Phospho Inositol Kinase3 (PIK-3)-dependent and Smad independent pathways (79; 80; 81; 82; 83) induce Fyn-dependent phosphorylation of IDO ITIMs.  A prototypic ITIM has the I/V/L/SxYxxL/V/F sequence (84), where x in place of an amino acid and Y is phosphorylation sites of tyrosines (85; 86).

Smad independent pathway stimulates SHP and PIK3 induce both SHP and IDO phosphorylation. Then, formed SHP-IDO complex can induce non-canonical (non-inflammatory) NF-kB pathway (64; 79; 80; 82) by phosphorylation of kinase IKKa to induce nuclear translocation of p52-Relb towards their targets.  Furthermore, the SHP-IDO complex also may inhibit IRAK1 (68). SHP-IDO complex activates genes through Nf-KB for production of Ido1 and Tgfb1 genes and secretion of IFNalpha/IFNbeta.  IFNa/IFNb establishes a second short positive feedback loop towards p52-RelB for continuous gene expression of IDO, TGFb1, IFNa and IFNb (87; 68).  However, SHP-IDO inhibited IRAK1 also activates p52-RelB.  Nf-KB induction at three path, one main and two positive feedback loops, is also critical.  Finally, based on TGF-beta1 induction (76) cellular differentiation occurs to stimulate naïve CD4+ T cell differentiation to regulatory T cells (Tregs).  In sum, TGF-b1 and IFNalpha/IFNbeta stimulate pDCs to keep inducing naïve T cells for generation of Treg cells at various stages, initiate, maintain, differentiate, infect, amplify, during long-term immune responses (67; 66).

Moonlighting function of Kyn/AhR is an adaptation mechanism after the catalytic (enzymatic) role of IDO depletes tryptophan and produce high concentration of Kyn induce Treg and Tr1 cell expansion leading Tregs to use TGFbeta for maintaining this environment (67; 76). In this role, Kyn pathway has positive-feedback-loop function to induce IDO expression.

In T cells, tryptophan starvation induces Gcn2-dependent stress signaling pathway, which initiates uncharged Trp-tRNA binding onto ribosomes. Elevated GCN2 expression stimulates elF2alfa phosphorylation to stop translation initiation (88). Therefore, most genes downregulated and LIP, an alternatively initiated isoform of the b/ZIP transcription factor NF-IL6/CEBP-beta (89).

This mechanism happens in tumor cells based on Prendergast group observations. As a result, not only IDO1 propagates itself while producing IFNalpha/IFNbeta, but also demonstrates homeostasis choosing between immunegenity by production of TH17or tolerance by Tregs. This mechanism acts like a see-saw. Yet, tolerance also can be broken by IL6 induction so reversal mechanism by SOC-3 dependent proteosomal degradation of the enzyme (90).  All proper responses require functional peripheral DCs to generate mature DCs for T cells to avoid autoimmunity (91).

Niacin (vitamin B3) is the final product of tryptophan catabolism and first molecule at Nicotinomic acid (NDA) Biosynthesis.  The function of IDO in tryptophan and NDA metabolism has a great importance to develop new clinical applications (40; 42; 41).  NAD+, biosynthesis and tryptophan metabolisms regulate several steps that can be utilize pharmacologically for reformation of healthy physiology (40).

IDO for protection in Microbial Infection with Toll-like Receptors

The mechanism of microbial response and infectious tolerance are complex and the origination of IDO based on duplication of microbial IDO (49).  During microbial responses, Toll-like receptors (TLRs) play a role to differentiate and determine the microbial structures as a ligand to initiate production of cytokines and pro-inflammatory agents to activate specific T helper cells (92; 93; 94; 95). Uniqueness of TLR comes from four major characteristics of each individual TLR by ligand specificity, signal transduction pathways, expression profiles and cellular localization (96). Thus, TLRs are important part of the immune response signaling mechanism to initiate and design adoptive responses from innate (naïve) immune system to defend the host.

TLRs are expressed cell type specific patterns and present themselves on APCs (DCs, MQs, monocytes) with a rich expression levels (96; 97; 98; 99; 93; 100; 101; 102; 87). Induction signals originate from microbial stimuli for the genesis of mature immune response cells.  Co-stimulation mechanisms stimulate immature DCs to travel from lymphoid organs to blood stream for proliferation of specific T cells (96).  After the induction of iDCs by microbial stimuli, they produce proinflammatory cytokines such as TNF and IL-12, which can activate differentiation of T cells into T helper cell, type one (Th1) cells. (103).

Utilizing specific TLR stimulation to link between innate and acquired responses can be possible through simple recognition of pathogen-associated molecular patterns (PAMPs) or co-stimulation of PAMPs with other TLR or non-TLR receptors, or even better with proinflammatory cytokines.   Some examples of ligand- TLR specificity shown in Table1, which are bacterial lipopeptides, Pam3Cys through TLR2 (92; 104; 105).  Double stranded (ds) RNAs through TLR3 (106; 107), Lipopolysaccharide (LPS) through TLR4, bacterial flagellin through TLR5 (108; 109), single stranded RNAs through TLR7/8 (97; 98), synthetic anti-viral compounds imiquinod through TLR 7 and resiquimod through TLR8, unmethylated CpG DNA motifs through TLR9 (Krieg, 2000).

IDO action

Then, the specificity is established by correct pairing of a TLR with its proinflammatory cytokines, so that these permutations influence creation and maintenance of cell differentiation. For example, leading the T cell response toward a preferred Th1 or Th2 response possible if the cytokines TLR-2 mediated signals induce a Th2 profile when combined with IL-2 but TLR4 mediated signals lean towards Th1 if it is combined with IL-10 or Il-12, (110; 111)  (112).

TLR ligand TLR Reference
Lipopolysaccharide, LPS TLR4 (96).  (112).
Lipopeptides, Pam3Cys TLR2 (92; 104; 105)
Double stranded (ds) RNAs TLR3 (106; 107)
Bacterial flagellin TLR5 (108; 109)
Single stranded RNAs TLR7/8 (97; 98)
Unmethylated CpG DNA motifs TLR9 (Krieg, 2000)
Synthetic anti-viral compounds imiquinod and resiquimod TLR7 and TLR8 (Lee J, 2003)

Furthermore, if the DCs are stimulated with IL-6, DCs relieve the suppression of effector T cells by regulatory T cells (113).

The modification of IDO+ monocytes manage towards specific subset of T cell activation with specific TLRs are significantly important (94).

The type of cell with correct TLR and stimuli improves or decreases the effectiveness of stimuli. Induction of IDO in monocytes by synthetic viral RNAs (isRNA) and CMV was possible, but not in monocyte derived DCs or TLR2 ligand lipopeptide Pam3Cys since single- stranded RNA ligands target TLR7/8 in monocytes derive DCs only (Lee J, 2003).  These data show that TLRs has ligand specificity, signal transduction pathways, expression profiles and cellular localization so design of experiments should follow these rules.

Conclusion:

Overall our purpose of this information is to find a method to manipulate IDO to correct/fix/modulate immune responses for clinical applications.  This first part of the review concerns the basic science information gained overall several years that lay the foundation that translational research scientist should familiar to develop a new technology for clinic. The first connection of IDO and human health came from a very natural event that is protection of pregnancy in human. The focus of the translational medicine is treatment of cancer or prevention/delay cancer by stem cell based Dendritic Cell Vaccine (DCvax) development.

References

1. Biochemistry of tryptophan in health and disease. BenderDA. 1983, Mol Aspects Med , pp. 6:101–197.

2. Molecular insights into substrate recognition and catalysis by indolamine 2,3-dioxygenase. Forouhar, F., Anderson, R., Mowat, C.F, et al. 2006, PNAS, pp. vol. 104, no:2, 473-478.

3. Importance of the Two Interferon-stimulated Response Element. Konan KV, Taylor, MW. 1996, J. Biol. Chem.-, pp. 19140-5.

4. induction of indolamine 2,3 dioxygenase: A mechanism of the anti-tumor activity of interferon gamma. Ozaki, Y., Edelstein, M.P., Duch, D.S. 1998, PNAS USA., pp. vol:85, 1242-1246.

5. Localization of the human indoleamine 2,3-dioxygenase (IDO) gene to the pericentromeric region of human chromosome 8. . Burkin, D. J., Kimbro, K. S., Barr, B. L., Jones, C., Taylor, M. W., Gupta, S. L. 1993, Genomics , pp. 17: 262-263.

6. Localization of indoleamine 2,3-dioxygenase gene (INDO) to chromosome 8p12-p11 by fluorescent in situ hybridization. Najfeld, V., Menninger, J., Muhleman, D., Comings, D. E., Gupta, S. L. 1993, Cytogenet. Cell Genet. , pp. 64: 231-232.

7. Molecular cloning, sequencing and expression of human interferon-gamma-inducible indoleamine 2,3-dioxygenase cDNA. . Dai, W., Gupta, S. L. 1990, Biochem. Biophys. Res. Commun. , pp. 168: 1-8.

8. Gene structure of human indoleamine 2,3-dioxygenase. Kadoya, A., Tone, S., Maeda, H., Minatogawa, Y., Kido, R. 1992, Biochem. Biophys. Res. Commun. , pp. 189: 530-536.

9. A gene atlas of th emouse and human protein-encoding transcriptomes. Andrew I. Su, Tim Wiltshire, Serge Batalov , Hilmar Lapp , Keith A. Ching , David Block, Jie Zhang , Richard Soden , Mimi Hayakawa , Gabriel Kreiman , Michael P. Cooke , John R. Walker , and John B. Hogenesch. 2004, PNAS, pp. vol. 101, no. 166062-6067 (10.1073/pnas.0400782101).

10. Indoleamine 2,3-dioxygenase production by human dendritic cells results in the inhibition of T cell proliferation. Hwu P, Du MX, Lapointe R, Do M, Taylor MW, Young HA. 2000, J. Immunol, pp. 164:3596–3599.

11. Inhibition of T cell proliferation by acrophage tryptophan catabolism. Munn, D.H. et al. 1999, J. Exp. Med., p. 189:1363.

12. HeLa cells cocultured with peripheral blood lymphocytes acquire an immuno-inhibitory phenotype through up-regulation of indoleamine 2,3-dioxygenase activity. Logan, G. J., Smyth, C. M. F., Earl, J. W., Zaikina, I., Rowe, P. B., Smythe, J. A., Alexander, I. E. 2002, Immunology, pp. 105:478-487.

13. Indoleamine 2,3-Dioxygenase – Is It an Immun Suppressor? Soliman H, Mediaville-Varela M, Antonia S. 2010, Cancer J. , pp. 16:354-359.

14. Targeting the immunoregulatory indoleamine 2,3-dioxygenase pathway in immunotherapy. Johnson BA, III, Baban B, Mellor AL. 2009, Immunotherapy. , pp. 645–661.

15. Indoleamine 2,3-dioxygenase and regulation of T cell immunity. AL., Mellor. 2005, Biochem Biophys Res Commun. , pp. 338(1):20–24.

16. Fallarino, F., Grohmann, U., Hwang, K. W., Orabona, C., Vacca, C., Bianchi, R., Belladonna, M. L., Fioretti, M. C.Modulation of tryptophan catabolism by regulatory T cells. Fallarino, F., Grohmann, U., Hwang, K. W., Orabona, C., Vacca, C., Bianchi, R., Belladonna, M. L., Fioretti, M. C., Alegre, M.-L., Puccetti, P. 2003, Nature Immun., pp. 4: 1206-1212.

17. CTLA-4-Ig regulates tryptophan catabolism in vivo. Grohmann, U., Orabona, C., Fallarino, F., Vacca, C., Calcinaro, F., Falorni, A., Candeloro, P., Belladonna, M. L., Bianchi, R., Fioretti, M. C., Puccetti, P. 2002, Nature Immun. , pp. 3: 1097-1101.

18. Reverse signaling through GITR ligand enables dexamethasone to activate IDO in allergy. Grohmann, U., Volpi, C., Fallarino, F., Bozza, S., Bianchi, R., Vacca, C., Orabona, C., Belladonna, M. L., Ayroldi, E., Nocentini, G., Boon, L., Bistoni, F., Fioretti, M. C., Romani, L., Riccardi, C., Puccetti, P. 2007, Nature Med., pp. 13:579-586.

19. Cells expressing indoleamine 2,3-dioxygenase inhibit T cell responses. Mellor, A. L., Keskin, D. B., Johnson, T., Chandler, P., Munn, D. H. 2002, J. Immun. , pp. 168: 3771-3776.

20. Chon, SY, Hassanain, HH, Piine, R., and Gupta, SL. 1995, J. Interferon Cytokine Res. , pp. 15, 517-526.

21. Levy, ED, KEsler, DS, Pine, R., Reich, N, and Darnell, JE.Jr et al. 1988, Genes Dev, pp. 2,383-393.

22. Benoist, C. and Manthis, D. 1990, Annu. Rev of Immunol., pp. 8, 681-715.

23. Dorn, A, Durand, B., Marling, C., Meur, M.L., Beoist, C., and Mathis, D. 1987, PNAS USA, pp. 34, 6249-6253.

24. Konan, K.V. Ph.D. Thesis. Transcriptional Regulation of the Indolamine 2,3-oxygenase Gene. s.l. : Indiana University, Bloominigton, 1995.

25. Tryptophan pyrrolase of rabbit intestine: D- and L–tryptophan cleaving enzyme or enzymes. Yamamoto, S., and Hayashi, O. 1967, J Biol Chem, pp. 242: 5260-5266.

26. Prevention of allogeneic fetal rejection by tryptophan catabolism. Munn, DH, Zhou M, Attwood JT, Bondarev I, Conway SJ, Marshall B, Brown C, Mellor AL. 1998, Science, pp. 281:1191–3.

27. Evidence for a tumoral immune resistance mechanismbased on tryptophan degradation by indoleamine 2,3-dioxygenase. Uyttenhove, C. et al. 2003, Nature Med. 9,, pp. 1269–1274 .

28. Pregnancy: success and failure within the Th1/Th2/Th3 paradigm. Raghupathy, R. 2001., Seminars in Immunology, pp. Volume 13, Issue 4, Pages 219–227.

29. Why is the fetal allograft not rejected? Davies, C. J. March 2007 , J ANIM SCI , pp. vol. 85 no. 13 suppl E32-E35 .

30. Exploring the mechanism of tryptoophan 2,3-dioxygenase. Thackray, S., Mowat, C.G., Chapman, K. 2008, Biochem. Society Transaction., pp. 36, 1120-1123.

31. The new life of a centenarian: signalling functions of NAD(P). Berger F, Ramírez-Hernández MH, Ziegler M. 2004, Trends Biochem Sci , pp. 29:111–118 .

32. Biochemistry of tryptophan in health and disease. DA, Bender. 1983, Mol Aspects Med, pp. 6:101–197.

33. Poliovirus induces indoleamine-2,3-dioxygenase and quinolinic acid synthesis in macaque brain. Heyes MP, Saito K, Jacobowitz D, Markey SP, Takikawa O, Vickers JH. 1992, FASEB J., pp. 6:2977–2989.

34. Sanni LA, Thomas SR, Tattam BN, Moore DE, Chaudhri G, Stocker R, Hunt NH 1998Dramatic changes in oxidative tryptophan metabolism along the kynurenine pathway in experimental cerebral and noncerebral malaria. . Sanni LA, Thomas SR, Tattam BN, Moore DE, Chaudhri G, Stocker R, Hunt NH. 1998, Am J Pathol, pp. 152:611–619.

35. Induction of pulmonary indoleamine 2,3-dioxygenase by intraperitoneal injection of bacterial lipopolysaccharide. . Yoshida R, Hayaishi O. 1978, Proc Natl Acad Sci USA , pp. 75:3998–4000.

36. Induction of indoleamine 2,3-dioxygenase in mouse lung during virus infection. . Yoshida R, Urade Y, Tokuda M, Hayaishi O. 1979, Proc Natl Acad Sci USA , pp. 76:4084–4086.

37. Induction of pulmonary indoleamine 2,3-dioxygenase by intraperitoneal injection of bacterial lipopolysaccharide. Yoshida R, Hayaishi. 1978, PNAS USA, pp. 3998-4000.

38. Sequence of human 2,3-dioxygenase (TDO2): presence of a glucorticoid response-like element composed of a GTT repeat and intronic CCCCT repeat. Comings DE, Muhleman D, Dietz G, Sherman M, Forest. 1995, Genomics, pp. 29:390-396165.

39. Studies on the biosynthesis of Nicotinamide adenine inucleotide. II.Arole of picolinic carboxylase in the Biosynthesisofnicotinamideadeninedinucleotidefromtryptophan in mammals. Ikeda M, Tsuji H, Nakamura S, Ichiyama A, Nishizuka Y, HayaishiO. 1965, J. Biol. Chem. , pp. 240: 1395-1401.

40. The Secret Life of NAD+: An Old Metabolite Controlling New Metabolic Signaling Pathways. Houtkooper R.H., Carles Cantó C. , Wanders, R.J. and Auwerx, J. 2010, Endocrine Reviews , pp. vol. 31 no. 2 194-223, doi: 10.1210/er.2009-0026.

41. Stimulation of Nicotinamide adenine dinucleotide biosynthetic pathways delays axonal degeneration after axotomy. Sasaki Y, Araki T, Milbrandt J. 2006, J Neurosci , pp. 26: 8484–8491.

42. European Nicotinamide Diabetes Intervention Trial (ENDIT): a randomised controlled trial of intervention before the onset of type 1 diabetes. Gale EA, Bingley PJ, Emmett CL, CollierT. 2004, Lancet., pp. 363:925–931.

43. Safety of high-dose nicotinamide: a review. Knip M, Douek IF, Moore WP, Gillmor HA, McLean AE, Bingley PJ, Gale EA. 2000, Diabetologia, pp. 43:1337–1345.

44. Large supplements of nicotinic acid and nicotinamide increase tissue NAD and poly(ADP-ribose) levels but do not affect diethylnitrosamine-induced altered hepatic foci in Fischer-344 rats. JacksonTM, Rawling JM, Roebuck BD, Kirkland JB. 1995, J Nutr , p. 125:1455.

45. Characterization and evolution of vertebrate indelamine 2,3-dihydrogenases IDOs from monotremes and marsupials. Yuasa, HJ, Ball, HJ, Ho, YF, Austin, CJ, et al. 2009, Comp. Biochem. Physiol. B. Biochem.. Mol. Biol., pp. 153 (2): 137-144.

46. Novel tryptophan catabolic enzyme IDO2 is the preferred biochemical target of the antitumor indolamine 2,3-dihydrogenase inhibitor compound D-1 methyl-tryptophan. Metz, R., Duhadaway, JB, Kamasani, U, Laury-Kleintop, L., Muller, AJ, Prendergast, GC. 2007, Cancer Res., pp. 67 (15): 7082-7087.

47. Total synthesis of exiguamines A and B inspired by catechollamine chemistry. Sofiyev, V, Lumb, JP, Volgraf, M., Trauner, D. 2012, Chemistry., pp. 18 (16): 4999-5005.

48. Molecular evolution of bacterial indolamine 2,3-dioxygenase. Yuasa, H J, Ushigoe, A, Ball, HJ. 2011, Gene., pp. 484 (1) : 22-31.

49. Infectious tolerance and the long-term acceptance of transplant tissue. Waldman, H., Adams, E., Fairchild, P., and Cobbold, S. 2006, J. Immunol., pp. 212:301-313.

50. Molecular evolution and characterizationof fungal indolamine 2,3-dioxygenases. Yuasa, HJ and Ball, HJ. 2012, J. Mol. Eval., pp. 72 (2): 160-168.

51. convergent evolution. The gene structure of Sulculus 41 kDa myoglobin is homologous with tht of human indolamine dioxygenase. Suzuki, T, Imai, K. 1996, Biochim. Biophys. Acta., pp. 1308(1):41-48.

52. Evolutionof myoglobin. Suzuki, T., Imai, K. 1998, Cell Mol Life Sci, pp. 54(9):979-1004.

53. A myoglobin evolved from indolamine 2,3-dioxygenase, trtptophan-degrading enzyme. Suzuki, T., Kawamichi, H., Imai, K. 1998, Comp Biochem Phisiol. Mol. Biol., pp. 121(2):117-128.

54. Do molluscs possess indolamine 2,3-dioxygenase? Yuasa, HJ and Suzuki, T. 2005, Comp. Biochem. Physiol. B. Biochem. Mol. Biol. , pp. (3) 445-454.

55. Comparison studies of the indolamine dioxygenase-like myoglobin from the abalone Sulculus diversicolor. Suzuki, T., Imai, K. 1997, Comp. Biohem. Phsiol B Biochem Mol Biol, pp. 117 (4)599-604.

56. Orchestration of the immune response by dendritic cells. Buckwalter MR, Albert ML. 2009, Curr Biol., pp. 19(9):355–361.

57. Dendritic cells and the control of immunity. Banchereau J, Steinman RM. 1998, Nature., pp. 245–52.

58. IDO expression by dendritic cells: tolerance and tryptophan catabolism. . Munn DH, Mellor AL. 2004, Nat Rev Immunol. , pp. 762–74.

59. Monocyte and Macrophage. Gordon, S. and Taylor, P.R. 2005, NATURE REVIEWS | IMMUNOLOGY , pp. vol:5, 953-964.

60. Blood monocytes consist of two principal subsets with distinct migratory properties. Geissmann F, Jung S, Littman DR. 2003, Immunity. , pp. 19:71–82.

61. Identification of a novel cell type in peripheral lymphoid organs of mice. I Morphology, quantitation, tissue distribution. . Steinman RM, Cohn ZA. 1973, J Exp Med., pp. 137(5):1142–1162.

62. T cell apoptosis by tryptophan catabolism. Fallarino F, Grohmann U, Vacca C, Bianchi R, Orabona C, Spreca A, Fioretti MC, Puccetti P. 2002, Cell Death Differ , pp. 9:1069–1077.

63. Kynurenine is a novel endothelium derived relaxing factor produced during inflammation. Wang, et al. 2010, Nat. Med., pp. 16(3): 279-285.

64. Activation of the noncanonical NF-kB pathway by HIV controls a Dendritic cell immunoregulatory phenotype. Manches, O. Fernandez, V.M.,, Plumas, J., Chaperot, L., and Bhardwaj, N. 2012, PNAS, pp. vol: 109, 14122-14127.

65. B cells inhibit induction of T cell-dependent tumor immunity. Qin, Z., Richter, G., Schuler, T., Ibe, S., Cao, X, Blakenstein, T. 1998, Nat. Med, p. 4:627.

66. Different partners, Opposite Outcmes: A new perspective of immunobiology of Indolamine 2,3 dioxygenase. Orabona, C., Pallotta, M.T., Grohman, U. 2012, Molecular Medicine., pp. 18:834-842.

67. Indolamine 2,3-dioxygenase: From catalyst to signaling function. Fallarino, F., Grohman, U., and Puccetti, P. 2012, Eurepean J. of Immunol. , pp. 42:1932-1937.

68. IDO: more than an enzyme. Chen, W. 2011, Nature Immonology, pp. 809-811.

69. Indolamine2,3-dehydrogenase in lung dendritic cells promotes Th2 responses and allergic inflammation. Xu, H., Oriss, T.B., Fei, M., Henry, A.C., Melgert, B.N., Chen, L., Mellor, A.L. 2008, PNAS USA, pp. 105: 6690-6695.

70. The immunoregulatory enzyme IDO paradoxically drives B-cellmediated autoimmunity. Scott, G.N., DuHadaway, J., Pigott, E., Ridge, N., Prendergast, G.C., Muller, A.J., Mandik-Nayak, L. 2009, J. Immunol., pp. 182:7509-7517.

71. Tryptophan deprivation sensitizes activated T cells to apoptosis prior to cell division. Lee GK, Park HJ, Macleod M, Chandler P, Munn DH, Mellor AL. 2002, Immunology , pp. 107:452–460.

72. Enzymology of NAD+ homeostasis in man. . Magni G, Amici A, Emanuelli M, Orsomando G, Raffaelli N, Ruggieri S. 2004, Cell Mol Life Sci , pp. 61:19–34.

73. Kynurenine pathway enzymes in dendritic cells initiate tolerogenesis in the absence of functional IDO. . Belladonna ML, Grohmann U, Guidetti P, Volpi C, Bianchi R, Fioretti MC, Schwarcz R, Fallarino F, Puccetti P. 2006, J Immunol. , pp. ;177:130–7.

74. An indogenous tumour promoting ligand of the human aryl hydrocarbon receptor. Opitz, et. al. 2011, pp. doi: 10.1038/nature10491,.

75. Inhibition of indoleamine 2,3-dioxygenase, animmunoregulatorytarget of the cancer suppression gene Bin1, potentiates cancer chemotherapy. Muller, A. J. et al. 2005, Nature Med. , pp. 11, 312–319 .

76. TGF-b; a master of all T cell trades. Li, M.O., Fravell, R.A. 2008, Cell. , pp. 134: 392-404.

77. Palotta, M.T. et al. 2011, Nat. Immunol., pp. 12:870-878.

78. Chen, W. et al. 2003, J. Exp. Immunol., p. 198: 1875.

79. Smads: transcriptional activators of TGF-beta responses. . Derynck R, Zhang Y, Feng XH. 1998, Cell , pp. 95 (6): 737–40. doi:10.1016/S0092-8674(00)81696-7.PMID 9865691. .

80. Smad transcription factors. Massagué J, Seoane J, Wotton D. 2005, Genes Dev, pp. 19 (23): 2783–810. doi:10.1101/gad.1350705. PMID .

81. A structural basis for mutational inactivation of the tumour suppressor Smad4. Shi Y, Hata A, Lo RS, Massagué J, Pavletich NP. 1997, Nature., pp. 388 (6637): 87–93.doi:10.1038/40431. PMID 9214508.

82. Promoting bone morphogenetic protein signaling through negative regulation of inhibitory Smads. Itoh F, Asao H, Sugamura K, Heldin CH, ten Dijke P, Itoh S. 2001, EMBO J., pp. 20 (15): 4132– doi:10.1093/emboj/20.15.4132. PMC 149146. PMID 11483516.

83. SMAD_Signaling_Network. http://www.sabiosciences.com. [Online] 2013. http://www.sabiosciences.com/pathway.php?sn=SMAD_Signaling_Network.

84. Immune inhibitory receptors. Revetch, J.V., and Lanier, L.L. 2000, Science., pp. 290:84-89.

85. Soc3 drives proteasomal degradation of indolamine 2,3-dioxygenase (IDO) and antagonizes IDO-dependent tolerogenesis. Orabona, C., Pallotta, M., Volpi, C., et al. 2008, PNAS USA, pp. 105: 20828-20833.

86. Cutting edge; silencing supressor of cytokine signaling3 expression in dendritic cells turns CD28-Ig from immune adjuvant to supressant. Orabona, C.,, Belladonna, M.L., et all. 2005, J. Immunol., pp. 174: 6582-6586.

87. Molecular signatures of T-cell inhibition in HIV-1 infection. Larsson, M., Shankar. E.M, Che, K.F., Ellegard, R., Barathan, M., Velu, V., and Kamarulzaman, A. 2013, Retrovirology, p. 10:31.

88. TGF-beta and CD4+CD25+ regulatory cells. Huber, S. and Schramn, C. 2006, Front. Bioscie., pp. 11:1014-1023.

89. Immune Escape as a fundemental trait of cancer; focus on IDO. Prendergast, G.C. 2008, Oncogene., pp. 27, 3889-3900.

90. Il-6 inhibits the tolerogenic functionof CD8+ dendritic cells expressing indolamine 2,3-dioxygenase. Grohman, U., Fallarino, F., et al. 2001, J. Immunol., pp. 167:708-714.

91. Avoiding horror autotoxicus: Th eimportance of dentritic cells in peripheral T cell tolerance. Steinman, R.M., and Nussenzweig, M.C. 2002, PNAS, pp. no:1, 351-358.

92. Dendritic-cell function in Toll-like receptor- and MyD88-knockout mice . Kaisho, T., Akira, S. 2001, Trends Immunol , pp. 22,78-83.

93. Innate sensing of self and non-self RNAs by Toll-like receptors. Sioud, M. 2006., Trends Mol Med., pp. 12:67–76.

94. Impaired expression of indoleamine 2, 3-dioxygenase in monocyte-derived dendritic cells in response to Toll-like receptor-7/8 ligands. Furset, G., Fløisand, Y. and Sioud, M. 2008, Immunology., pp. 123(2): 263–271, doi: 10.1111/j.1365-2567.2007.02695.x.

95. Toll-;ike receptor 9 mediated induction of the immunorepressor pathway of tryptophan metabolism. Fallarino, F., and Puccetti, P. 2006, Eur. J. of Imm., pp. 36:8-11.

96. Toll-like receptors and host defense against microbial pathogens: bringing specificity to the innate immune system. . Netea MG, der Graaf C, Van der Meer JWM, Kullberg BJ. 2004, J Leukoc Biol. , pp. 75:749–55.

97. Species-specific recognition of single-stranded RNA via toll-like receptor 7 and 8. . Heil F, Hemmi H, Hochrein H, et al. 2004, Science. , pp. 303:1526–9.

98. Innate antiviral responses by means of TLR7-mediated recognition of single-stranded RNA. . Diebold SS, Kaisho T, Hemmi H, Akira S, Reis e Sousa C. 2004., Science. , pp. 303:1529–31. .

99. The role of CpG motifs in innate immunity. Krieg, A.M. 2000., Curr Opin Immunol., pp. 12:35–43.

100. Anendogenous tumour-promoting ligand of the human aryl hydrocarbon receptor. Opitz, C.A., Litzenburger, U.M., Sahm, F., Ott,M., Tritschler, I., Trump, S. 2011, Nature, pp. vol 478; 197-203.

101. Impaired impression of Indolamine 2,3-deoxygenase in monocyte derived DCs in response to TLR-7/8. Furset, G., Floisand, Y., Sioud, M. 2007, Immunology, pp. 263-271.

102. Activationof the noncanonical NF-kB pathway by HIV controls a Dendritic cell immunoregulatory phenotype. Manches, O. Fernandez, V.M.,, Plumas, J., Chaperot, L., and Bhardwaj, N. 2012, PNAS, pp. vol: 109, 14122-14127.

103. Regulation of dendritic cell numbers and maturation by lipopolysaccharide in vivo . de Smedt, T., Pajak, B., Muraille, E., Lespagnard, L., Heinen, E., De Baetselier, P., Urbain, J., Leo, O., Moser, M. 1996, J. Exp. Med., pp. 184,1413-1424.

104. Subsets of dendritic cell precursors express different Toll-like receptors and respond to different microbial antigens . Kadowaki, N., Ho, S., Antonenko, S., de Waal Malefyt, R., Kastelein, R. A., Bazan, F., Liu, Y-J. 2001, J. Exp. Med., pp. 194,863-869 .

105. TRAF6 is a critical factor for dendritic cell maturation and development . Kobayashi, T., Walsh, P. T., Walsh, M. C., Speirs, K. M., Chiffoleau, E., King, C. G., Hancock, W. W., Caamano, J. H., Hunter, C. A., Scott, P., Turka, L. A., Choi, Y. 2003, Immunity , pp. 19,353-363 .

106. Activation of interferon regulatory factor-3 via toll-like receptor 3 and immunomodulatory functions detected in A549 lung epithelial cells exposed to misplaced U1-snRNA. Sadik CD, Bachmann M, Pfeilschifter J, Mühl H. 2009, Nucleic Acids Res. , pp. 37(15):5041-56. doi: 10.1093/nar/gkp525. Epub 2009 Jun 18.

107. Triggering of the dsRNA sensors TLR3, MDA5, and RIG-I induces CD55 expression in synovial fibroblasts. Karpus ON, Heutinck KM, Wijnker PJ, Tak PP, Hamann J. 2012, PLoS One., p. 7(5):e35606. doi: 10.1371/journal.pone.0035606. Epub 2012 May 10.

108. The structure of the TLR5-flagellin complex: a new mode of pathogen detection, conserved receptor dimerization for signaling. Lu J, Sun PD. 2012, Sci Signal., p. 5(216):pe11. doi: 10.1126/scisignal.2002963. .

109. Flagellin/Toll-like receptor 5 response was specifically attenuated by keratan sulfate disaccharide via decreased EGFR phosphorylation in normal human bronchial epithelial cells. Shirato K, Gao C, Ota F, Angata T, Shogomori H, Ohtsubo K, Yoshida K, Lepenies B, Taniguchi N. 2013, Biochem Biophys Res Commun., pp. doi:pii: S0006-291X(13)00779-1. 10.1016/j.bbrc.2013.05.009. [Epub ahead of print].

110. Differential induction of interleukin-10 and interleukin-12 in dendritic cells by microbial Toll-like receptor activators and skewing of T-cell cytokine profiles Infect. Qi, H., Denning, T. L., Soong, L. 2003, Immun. , pp. 71,3337-3342 .

111. Thoma-Uszynski, S., Kiertscher, S. M., Ochoa, M. T., Bouis, D. A., Norgard, M. V., Miyake, K., Godowski, P. J., Roth, M. D.Activation of Toll-like receptor 2 on human dendritic cells triggers induction of IL-12, but not IL-10 . Thoma-Uszynski, S., Kiertscher, S. M., Ochoa, M. T., Bouis, D. A., Norgard, M. V., Miyake, K., Godowski, P. J., Roth, M. D., Modlin, R. L. 2000, J. Immunol. , pp. 165,3804-3810.

112. Toll-like receptor 2 (TLR2) and TLR4 differentially activate human dendritic cells . Re, F., Strominger, J. L. 2001, J. Biol. Chem. , pp. 276,37692-37699.

113. Pasare, C., Medzhitov, R. (2003) Toll pathway-dependent blockade of CD4+CD25+ T cell-mediated suppression by dendritic cells. Pasare, C., Medzhitov, R. 2003, Science , pp. 299,1033-1036 .

 

  

Read Full Post »

Larry H Bernstein, MD, Writer, Curator
http://pharmaceutical intelligence.com/2013/06/22/ Demythologizing sharks, cancer, and shark fins/lhbern

Screen Shot 2021-07-19 at 6.26.48 PM

Word Cloud By Danielle Smolyar

Sharks have survived some 400 million years on Earth. Could their longevity be due in part to an extraordinary resistance to cancer and other diseases? If so, humans might someday benefit from the shark’s secrets—but leading researchers caution that today’s popular shark cartilage “cancer cures” aren’t part of the solution.

The belief that sharks do not get cancer is not supported in fact, but it is the basis for decimating a significant part of the shark population for shark fins, and for medicinal use.  The unfortunate result is that there is no benefit.

A basis for this thinking is that going back to the late 1800s, sharks have been fished commercially and there have been few reports of anything out of the ordinary when removing internal organs or preparing meat for the marketplace.  In addition, pre-medical students may have dissected dogfish sharks in comparative anatomy, but you don’t see reports of cancerous tumors.

Carl Luer of the MOTE Marine Laboratory’s Center for Shark Research in Sarasota, Florida, has been studying sharks’ cancer resistance for some 25 years.  Systematic surveys of sharks are difficult to conduct, as capturing the animals in large numbers is time-consuming, and cancer tests would likely require the deaths of large numbers of sharks. Of the thousands of fish tumors in the collections of the Smithsonian Institution, only about 15 are from elasmobranchs, and only two of these are thought to have been malignant.

Scientists have been studying cancerous tumors in sharks for 150 years.

The first chondrichthyes’ (cartilaginous fishes, including sharks) tumor was found on a skate and recorded by Dislonghamcps in 1853. The first shark tumor was recorded in 1908. Scientists have since discovered benign and cancerous tumors in 18 of the 1,168 species of sharks. Scarcity of studies on shark physiology has perhaps allowed this myth to be accepted as fact for so many years.

In April 2000, John Harshbarger and Gary Ostrander countered this shark myth with a presentation on 40 benign and cancerous tumors known to be found in sharks, and soon after a blue shark was found with cancerous tumors in both its liver and testes. Several years later a cancerous gingival tumor was removed from the mouth of a captive sand tiger shark, Carcharias Taurus. Advances in shark research continue to produce studies on types of cancer found in various species of shark.  Sharks, like fish, encounter and take in large quantities of environmental pollutants, which may actually make them more susceptible to tumorous growth. Despite recorded cases of shark cancer and evidence that shark cartilage has no curative powers against cancer sharks continue to be harvested for their cartilage.

Sharks and their relatives, the skates and rays, have enjoyed tremendous success during their nearly 400 million years of existence on earth, according to Dr. Luer. He points out that one reason for this certainly is their uncanny ability to resist disease. Sharks do get sick, but their incidence of disease is much lower than among the other fishes. While statistics are not available on most diseases in fishes, reptiles, amphibians, and invertebrates, tumor incidence in these animals is carefully monitored by the Smithsonian Institution in Washington, D.C.

The Smithsonian’s enormous database, called the Registry of Tumors in Lower Animals, catalogs tissues suspected of being tumorous, including cancers, from all possible sources throughout the world. Of the thousands of tissues in the Registry, most of them are from fish but only a few are from elasmobranchs. Only 8 to 10 legitimate tumors are among all the shark and ray tissues examined, and only two of these are thought to have been malignant.

An observation by Gary Ostrander, a Professor at Johns Hopkins University, is that there may be fundamental differences in shark immune systems so that they aren’t as prone to cancer.  The major thrust of the Motes research focuses on the immunity of sharks and their relatives the skates and rays. While skates aren’t as interesting to the public as their shark relatives, their similar biochemical immunology and their ability to breed in captivity make them perhaps more vital to Luer’s lab work.   The result is to study the differences and similarities to the higher animals, and what might possibly be the role of the immune system in their low incidence of disease.

This low incidence of tumors among the sharks and their relatives has prompted biochemists and immunologists at Mote Marine Laboratory (MML) to explore the mechanisms that may explain the unusual disease resistance of these animals. To do this, they established the nurse shark and clearnose skate as laboratory animals. They designed experiments to see whether tumors could be induced in the sharks and skates by exposing them to potent carcinogenic (cancer-causing) chemicals, and then monitored pathways of metabolism or detoxification of the carcinogens in the test animals. While there were similarities and differences in the responses when compared with mammals, no changes in the target tissues or their genetic material ever resulted in cancerous tumor formation in the sharks or skates.

The chemical exposure studies led to investigations of the shark immune system. As with mammals, including humans, the immune system of sharks probably plays a vital role in the overall health of these animals. But there are some important differences between the immune arsenals of mammals and sharks. The immune system of mammals typically consists of two parts which utilize a variety of immune cells as well as several classes of proteins called immunoglobulins (antibodies).

Compared to the mammalian system, which is quite specialized, the shark immune system appears primitive but remarkably effective. Sharks apparently possess immune cells with the same functions as those of mammals, but the shark cells appear to be produced and stimulated differently. Furthermore, in contrast to the variety of immunoglobulins produced in the mammalian immune system, sharks have only one class of immunoglobulin (termed IgM). This Immunoglobulin normally circulates in shark blood at very high levels and appears to be ready to attack invading substances at all times.

Another difference lies in the fact that sharks, skates, and rays lack a bony skeleton, and so do not have bone marrow. In mammals, immune cells are produced and mature in the bone marrow and other sites, and, after a brief lag time, these cells are mobilized to the bloodstream to fight invading substances. In sharks, the immune cells are produced in the spleen, thymus and unique tissues associated with the gonads (epigonal organ) and esophagus (Leydig organ). Some maturation of these immune cells occurs at the sites of cell production, as with mammals. But a significant number of immune cells in these animals actually mature as they circulate in the bloodstream. Like the ever-present IgM molecule, immune cells already in the shark’s blood may be available to respond without a lag period, resulting in a more efficient immune response.

Research was being carried out during the 1980’s at the Massachusetts Institute of Technology (MIT) and at Mote Marine Laboratory designed to understand how cartilage is naturally able to resist penetration by blood capillaries. If the basis for this inhibition could be identified, it was reasoned, it might lead to the development of a new drug therapy. Such a drug could control the spread of blood vessels feeding a cancerous tumor, or the inflammation associated with arthritis.

The results of the research showed only that a very small amount of an active material, with limited ability to control blood vessel growth, can be obtained from large amounts of raw cartilage. The cartilage must be subjected to several weeks of harsh chemical procedures to extract and concentrate the active ingredients. Once this is done, the resulting material is able to inhibit blood vessel growth in laboratory tests on animal models, when the concentrated extract is directly applied near the growing blood vessels.  One cannot assume that comparable material in sufficient amount and strength is released passively from cartilage when still in the animal to inhibit blood vessel growth anywhere in the body.

Tumors release chemicals stimulating the capillary growth so a nutrient-rich blood supply is created to feed the tumorous cells. This process is called angiogenesis. If scientists can control angiogenesis, they could limit tumor growth. Cartilage lacks capillaries running through it. Why should this be a surprise?  Cartilage cells are called chondrocytes, and they fuction to produce a acellular interstitial matrix consisting of hyaluronan (complex carbohydrate formed from hyaluronic acid and chondroitin sulfate) which is protective of interlaced collagen.   Early research into the anti-angiogenesis properties of cartilage revealed that tiny amounts of proteins could be extracted from cartilage, and, when applied in concentration to animal tumors, the formation of capillaries and the spread of tumors was inhibited.

Henry Brem and Judah Folkman from the Johns Hopkins School of Medicine first noted that cartilage prevented the growth of new blood vessels into tissues in the 1970s. The creation of a blood supply, called angiogenesis, is a characteristic of malignant tumors, as the rapidly dividing cells need lots of nutrients to continue growing.  It is valuable to consider that these neovascular generating cells are not of epithelial derivation, but are endothelial and mesenchymal. To support their very high metabolism, tumors secrete a hormone called ‘angiogenin’ which causes nearby blood vessels to grow new branches that surround the tumor, bringing in nutrients and carrying away waste products

Brem and Folkman began studying cartilage to search for anti-angiogenic compounds. They reasoned that since all cartilage lacks blood vessels, it must contain some signaling molecules or enzymes that prevent capillaries from forming. They found that inserting cartilage from baby rabbits alongside tumors in experimental animals completely prevented the tumors from growing. Further research showed calf cartilage, too, had anti-angiogenic properties.

A young researcher by the name of Robert Langer repeated the initial rabbit cartilage experiments, except this time using shark cartilage. Indeed, shark cartilage, like calf and rabbit cartilage, inhibited blood vessels from growing toward tumors. Research by Dr. Robert Langer of M.I.T. and other workers revealed a promising anti-tumor agent obtainable in quantity from shark cartilage. The compound antagonistic to the effects of angiogenin, called ‘angiogenin inhibitor’, inhibits the formation of new blood vessels, neovascularization, that is essential for supporting cancer growth.

The consequence of the”shark myth” is not surprising. An inhabitant of the open ocean, the Silky Shark is ‘hit’ hard by the shark fin and shark cartilage industries – away from the prying eyes of a mostly land bound public. As a consequence of this ‘invisibility’, mortality of Silkies is difficult to estimate or regulate.  North American populations of sharks have decreased by up to 80% in the past decade, as cartilage companies harvest up to 200,000 sharks every month in US waters to create their products. One American-owned shark cartilage plant in Costa Rica is estimated to destroy 2.8 million sharks per year. Sharks are slow growing species compared to other fish, and simply cannot reproduce fast enough to survive such sustained, intense fishing pressure. Unless fishing is dramatically decreased worldwide, a number of species of sharks will go extinct before we even notice.

Sources:
1.  National Geographic News: NATIONALGEOGRAPHIC.COM/NEWS

2. Do Sharks Hold Secret to Human Cancer Fight?
by Brian Handwerk for National Geographic News.  August 20, 2003

3. Busting Marine Myths: Sharks DO Get Cancer!
by Christie Wilcox   November 9th 2009

Sand tiger shark (Carcharias taurus) at the Ne...

Sand tiger shark (Carcharias taurus) at the Newport Aquarium. (Photo credit: Wikipedia)

Angiogenesis

Angiogenesis (Photo credit: Wikipedia)

The immune response

The immune response (Photo credit: Wikipedia)

Read Full Post »

Reporter: Aviva Lev-Ari, PhD, RN

Follicular T-helper cell recruitment governed by bystander B cells and ICOS-driven motility

Nature 496, 523–527 (25 April 2013)

 

24 April 2013

Germinal centres support antibody affinity maturation and memory formation1. Follicular T-helper cells promote proliferation and differentiation of antigen-specific B cells inside the follicle23. A genetic deficiency in the inducible co-stimulator (ICOS), a classic CD28 family co-stimulatory molecule highly expressed by follicular T-helper cells, causes profound germinal centre defects45, leading to the view that ICOS specifically co-stimulates the follicular T-helper cell differentiation program267. Here we show that ICOS directly controls follicular recruitment of activated T-helper cells in mice. This effect is independent from ICOS ligand (ICOSL)-mediated co-stimulation provided by antigen-presenting dendritic cells or cognate B cells, and does not rely on Bcl6-mediated programming as an intermediate step. Instead, it requires ICOSL expression by follicular bystander B cells, which do not present cognate antigen to T-helper cells but collectively form an ICOS-engaging field. Dynamic imaging reveals ICOS engagement drives coordinated pseudopod formation and promotes persistent T-cell migration at the border between the T-cell zone and the B-cell follicle in vivo. When follicular bystander B cells cannot express ICOSL, otherwise competent T-helper cells fail to develop into follicular T-helper cells normally, and fail to promote optimal germinal centre responses. These results demonstrate a co-stimulation-independent function of ICOS, uncover a key role for bystander B cells in promoting the development of follicular T-helper cells, and reveal unsuspected sophistication in dynamic T-cell positioning in vivo.

Read Full Post »

We celebrate 1,544 articles, 5,683 tags, 303,847 views, first article 4/30/2012 – Open Access Online Scientific Journal

Reporter: Aviva Lev-Ari, PhD, RN

Updated on 11/13/2023

2023 Update from LPBI Group

https://pharmaceuticalintelligence.com/2022/02/21/update-from-lpbi-group/

Update on 1/1/2023 by Srinivas Sriram and Abhisar Anand

1/1/2023- 2,205,188 views

Content

1/1/2023- 6,162 Posts

754 Categories

10,688 Tags

This image has an empty alt attribute; its file name is ArticleID-41.png

WordCloud Image Produced by Adam Tubman

WordPress.com Annual Report for 2013

The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 220,000 times in 2013. If it were an exhibit at the Louvre Museum, it would take about 9 days for that many people to see it.

In 2013, there were 958 new posts, growing the total archive of this blog to 1,505 posts. There were 982 pictures uploaded, taking up a total of 253 MB. That’s about 3 pictures per day.

The busiest day of the year was September 19th with 2,501 views. The most popular post that day was Is the Warburg Effect the Cause or the Effect of Cancer: A 21st Century View?.

SOURCE

http://pharmaceuticalintelligence.com/2013/annual-report/

UPDATES on 1/4/2014

On 1/4/2014

We celebrate 1,544 articles, 5,683 tags, 303,847 views, first article 4/30/2012 – Open Access Online Scientific Journal  

UPDATED on 11/10/2013

On April 15, 2013

We celebrate 800 articles, 4040 tags, 158,147 views, first article 4/30/2012 – Open Access Online Scientific Journal

On November 10, 2013

We celebrate 1,338 articles, 5,316 tags, 275,104 views, first article 4/30/2012 – Open Access Online Scientific Journal

Encouragement by the Founder: Aviva Lev-Ari, PhD, RN

Updated CURRENT NEEDS on 1/1/2014:

We are SEEKING resources to satisfy our needs at present time:

1. Efforts to find a buyer for our Scientific Journal for 12/2014

http://pharmaceuticalintelligence.com

2. Efforts to find a Publisher for a hardcopy version of a Three Volume Series  onCardiovascular Diseases

3. Find few additional Authors for the Journal

4. Find Editors for Cardiovascular Diseases e-Books

5. Find one Editor for Infectious Diseases

6. Find one Editor for immunology

7. Find few Patent Holders in BioMed, for our Business Partner in Shanghai to be connected to Private Equity investors

8. Find Angel Investors for Venture #5

Business Portfolios

VENTURE #1:

e-Publishing: Medicine, HealthCare, Life Sciences, BioMed, Pharmaceutical

  • Open Access Online Scientific Journal

http://pharmaceuticalintelligence.com

Site statistics http://pharmaceuticalintelligence.com/wp-admin/index.php?page=stats

  • Scoop.it!.com
  1. http://www.scoop.it/t/cardiotoxicity
  2. http://www.scoop.it/t/cardiovascular-and-vascular-imaging
  3. http://www.scoop.it/t/cardiovascular-disease-pharmaco-therapy

VENTURE #2:

1. BioMedical e-Books Series:

http://pharmaceuticalintelligence.com/biomed-e-books/

2. on Amazon’s Kindle e-Books List since 6/2013

3. Plans for Volume 1,2,3 – Hardcover

 

VENTURE #3:

International Scientific Delegations

http://pharmaceuticalintelligence.com/scientific-delegation/

  • Shanghai, May 2014 
  • Barcelona, Spain, November 2014
  • Amsterdam, May 2015
  • Geneva, November 2015

VENTURE #4:

Joint Ventures

http://pharmaceuticalintelligence.com/joint-ventures/

  • Leaders in Pharmaceutical Business Intelligence AND NEW MEDICINE, INC. [ongoing]
  • Leaders in Pharmaceutical Business Intelligence AND Bio-Tree Systems [pending Bio-Tree finding funding]
  • Leaders in Pharmaceutical Business Intelligence AND Lou Pharma [pending finding Licensees for drugs manufactured in Spain]
  • Leaders in Pharmaceutical Business Intelligence AND AlphaSzenszor Inc.
  • Leaders in Pharmaceutical Business Intelligence AND ValveCure, LLC

VENTURE #5:

Invented HERE!

1.  Development of a NEW Nitric Oxide monitor to Alpha Szenszor Inc. sensor portfolio. A concept for a low cost POC e-nose, capable of real time ppb detection of Cancer
The Cancer Team at Leaders in Pharmaceutical Business Intelligence under the leadership of Dr. Williams

2.  Development of a NEW Nitric Oxide monitor to Alpha Szenszor Inc. sensor portfolio. A concept for Inhaled Nitric Oxide for the Adult HomeCare Market –

IP by Dr. Pearlman and Dr. A. Lev-Ari

a.  iknow iNO is i-kNOw – Inhaled Nitric Oxide for the HomeCare Market

http://pharmaceuticalintelligence.com/2013/10/16/iknow-ino-is-i-know-inhaled-nitric-oxide-for-the-homecare-market/

b. electronic Book on Nitric Oxide by Nitric Oxide Team @ Leaders in Pharmaceutical Business Intelligence (LPBI)

Perspectives on Nitric Oxide in Disease Mechanisms

http://www.amazon.com/dp/B00DINFFYC

c. The rationale and use of inhaled NO in Pulmonary Artery Hypertension and Right Sided Heart Failure

Larry H. Bernstein 8/20/2012

d. Inhaled Nitric Oxide in Adults: Clinical Trials and Meta Analysis Studies – Recent Findings

3.  Cancer Genomics for NEW product development in diagnosis and treatment of Cancer Patients using sensory technology with applications for Radiation Therapy – The Cancer Team at Leaders in Pharmaceutical Business Intelligence under leadership of Dr. Sidney Kadish.

4.  Developing Mitral Valve Disease: MRI Methods and Devices for Percutaneous Mitral Valve Replacement and Mitral Valve Repair
Augmentation of Patented Technology using RF – Dr. Pearlman’s IP Non-Hardware Mitral Annuloplasty – Dr. Justin D. Pearlman

http://pharmaceuticalintelligence.com/joint-ventures/valvecure-llc/non-hardware-mitral-annuloplasty-dr-justin-d-pearlman/

5.  Novel Technology using MRI for Vascular Lesions, Tumors, Hyperactive Glands and non-Surgical Cosmetic Reconstruction – Dr. Pearlman’s IP

http://pharmaceuticalintelligence.com/biomed-e-books/series-a-e-books-on-cardiovascular-diseases/httppharmaceuticalintelligence-combiomed-e-bookscardiovascular-diseases-causes-risks-and-management/cvd-business-affairs/mitral-valve-disease-mri-methods-and-devices/

VENTURE # 6:

PRESS Coverage of Conferences

http://pharmaceuticalintelligence.com/press-coverage/

Top Authors for all days ending 2014-01-05 (Summarized)

 

Author Views
2012pharmaceutical 96,387
larryhbern 42,452
tildabarliya 17,394
Dr. Sudipta Saha 13,882
Dror Nir 8,909
ritusaxena 8,851
sjwilliamspa 8,456
aviralvatsa 4,681
zraviv06 2,402
anamikasarkar 2,132
Demet Sag, Ph.D., CRA, GCP 2,072
pkandala 1,818
Alan F. Kaul, PharmD., MS, MBA, FCCP 1,329
zs22 1,153
megbaker58 1,005
Aashir Awan, Phd 775
jdpmdphd 344
Ed Kislauskis 244
jukkakarjalainen 168
apreconasia 148

 

 

Read Full Post »

Reporter: Aviva Lev-Ari, PhD, RN

 

The healing element is also the enemy – an enigma probed by Hebrew University Lautenberg Center researchers

April 3, 2013

Jerusalem – The same factor in our immune system that is instrumental in enabling us to fight off severe and dangerous inflammatory ailments is also a player in doing the opposite at a later stage, causing the suppression of our immune response.

Why and how this happens and what can be done to mediate this process for the benefit of mankind is the subject of an article published online in the journal Immunity by Ph.D. student Moshe Sade-Feldman and Professor Michal Baniyash of the Lautenberg Center for General and Tumor Immunology at The Hebrew University Faculty of Medicine.
Chronic inflammation poses a major global health problem and is common to different pathologies — such as autoimmune diseases (diabetes, rheumatoid arthritis, lupus and Crohn’s), chronic inflammatory disorders, chronic infections (HIV, leprosy, leishmaniasis) and cancer. Cumulative data indicate that at a certain stage of each of these diseases, the immune system becomes suppressed and results in disease progression.
In their previous work, The Hebrew University researchers had shown that in the course of chronic inflammation, unique immune system cells with suppressive features termed myeloid derived suppressor cells (MDSCs) are generated in the bone marrow and migrate into the body’s organs and blood, imposing a general immune suppression.
A complex network of inflammatory compounds persistently secreted by the body’s normal or cancerous cells support MDSC accumulation, activation and suppressive functions. One of these compounds is tumor necrosis factor-a (TNF-a), which under acute immune responses (short episodes), displays beneficial effects in the initiation of immune responses directed against invading pathogens and tumor cells.
However, TNF-a also displays harmful features under chronic responses, as described in pathologies such as rheumatoid arthritis, psoriasis, type II diabetes, Crohn’s disease and cancer, leading to complications and disease progression. Therefore, today several FDA- approved TNF-a blocking reagents are used in the clinic for the treatment of such pathologies.
What has remained unclear until now, however, is just how TNF-a plays its deleterious role in manipulating the host’s immune system towards the generation of a suppressive environment.
In their work, The Hebrew University researchers discovered the mechanisms underlying the TNF-a  function, a key to controlling this factor and manipulating it, perhaps, for the benefit of humans.  Using experimental mouse models, they showed unequivocally how TNF-a is critical in the induction of immune suppression generated during chronic inflammation. The TNF-a was seen to directly affect the accumulation and suppressive function of MDSCs, leading to an impaired host’s immune responses as reflected by the inability to respond against invading pathogens or against developing tumors.
Further, the direct role of how TNF-a works in humans was mimicked by injecting the FDA-approved anti-TNF-a drug, etanercept, into mice at the exacerbated stage of an inflammatory response, when MDSC accumulation was observed in the blood. The etanercept treatment changed the features of MDSCs and abolished their suppressive activity, leading to the restoration of the host’s immune function.
Taken together, the results show clearly how the TNF-a-mediated inflammatory response, whether acute or chronic, will dictate its beneficial or harmful consequence on the immune system. While during acute inflammation TNF-a is vital for immediate immune defense against pathogens and clearance of tumor cells, during chronic inflammation — under conditions where the host is unable to clear the pathogen or the tumor cells — TNF-a is harmful due to the induction of immune suppression.
These results, providing new insight into the relationship between TNF-a and the development of an immune suppression during chronic inflammation, may aid in the generation of better therapeutic strategies against various pathologies when elevated TNF-a and MDSC levels are detected, as seen, for example, in tumor growths.

 

Read Full Post »

IRF-1 Deficiency Skews the Differentiation of Dendritic Cells

Reporter: Larry H Bernstein, MD, FCAP

 

 

IFN Regulatory Factor-1 Negatively Regulates CD4+CD25+ Regulatory T Cell Differentiation by Repressing Foxp3 Expression1

 

Alessandra Fragale*, Lucia Gabriele†, Emilia Stellacci*, Paola Borghi†,…. and Angela Battistini2,*
The Journal of Immunology   Aug 1, 2008; 181(3): 1673-1682

Regulatory T (Treg) cells are critical in inducing and maintaining tolerance. Despite progress in understanding the basis of immune tolerance,

  • mechanisms and molecules involved in the generation of Treg cells remain poorly understood.

IFN regulatory factor (IRF)-1 is a pleiotropic transcription factor implicated in the regulation of various immune processes. In this study, we report that IRF-1 negatively regulates CD4+CD25+ Treg cell

  • development and function by specifically repressing Foxp3 expression.

IRF-1-deficient (IRF-1−/−) mice showed a selective and marked increase of highly activated and differentiated CD4+CD25+Foxp3+ Treg cells in thymus and in all peripheral lymphoid organs. Furthermore,

  • IRF-1−/− CD4+CD25− T cells showed extremely high bent to differentiate into CD4+CD25+Foxp3+ Treg cells, whereas
  • restoring IRF-1 expression in IRF-1−/− CD4+CD25− T cells
    • impaired their differentiation into CD25+Foxp3+ cells.

Functionally, both isolated and TGF-β-induced CD4+CD25+ Treg cells from IRF-1−/− mice

  • exhibited more increased suppressive activity than wild-type Treg cells.

Such phenotype and functional characteristics were explained at a mechanistic level by the finding that

  • IRF-1 binds a highly conserved IRF consensus element sequence (IRF-E) in the foxp3 gene promoter in vivo and
  • negatively regulates its transcriptional activity.

We conclude that IRF-1 is a key negative regulator of CD4+CD25+ Treg cells

  • through direct repression of Foxp3 expression.
Introduction

Tolerance is critical for prevention of autoimmunity and maintenance of immune homeostasis by active suppression of inappropriate immune responses. Suppression has a dedicated population of  T cells that

  • control the responses of other T cells.

This cell population, referred to as regulatory T (Treg)3 cells, actually comprises several subsets, including naturally occurring CD4+CD25+ Treg cells that arise in thymus. Once generated,

  • thymic Treg cells are exported to peripheral tissues, and
  • comprise 5–10% of peripheral CD4+ T cells (1, 2, 3).

CD4+CD25+ Treg cells are characterized by

  • constitutive expression of IL-2Rα (CD25), CTLA-4, and glucocorticoid-induced TNFR family-related gene; moreover,
  • they express CD62 ligand (CD62L) and are mainly CD45RBlow (4).

In contrast to cell surface markers, which can be shared with other T cells populations,

  • the forkhead/winged-helix family transcriptional repressor Foxp3 is
  • specifically expressed in CD4+CD25+ Treg cells and
  • rigorously controls their development and function (5, 6, 7).

Functionally after TCR stimulation, CD4+CD25+ Treg cells can

  • mediate strong suppression of proliferation and
  • IL-2 production by CD4+ T cells both in vivo and in vitro (8).

Although mechanisms of suppression are not fully understood,

  • they appear to be cell contact-mediated, whereas
  • the relative contribution of soluble cytokines remains controversial
    • with differences between in vitro and in vivo results (1, 8, 9).

Indeed, the involvement of cytokines in the suppressor function of CD4+CD25+ Treg cells has been proposed in vivo,

  • where they are able to produce IL-10 and TGF-β (10, 11, 12), and
  • importantly, IL-10 activity has been recently associated with the function of TGF-β-induced CD4+CD25−CD45RBlow cells (13).

Beside naturally occurring CD4+CD25+ Treg cells, CD4+CD25+ Treg cells can also be

  • induced (inTreg) in vivo or in vitro after TCR stimulation and TGF-β treatment,
  • acquiring expression of CD25 and Foxp3 both in mice (14, 15, 16) and humans (17, 18, 19, 20),
    • although with characteristic functional differences (20).

Despite extensive studies on the role of Foxp3 in inducing and maintaining tolerance, little information on regulation of its expression is available. Transcription factors of the IFN regulatory factor (IRF) family participate in

  • the early host response to pathogens,
  • in immunomodulation and
  • hematopoietic differentiation (21).

Nine members of this family have been identified based on a unique helix-turn-helix DNA binding domain, located at

  • the N terminus that is responsible for binding to the IRF consensus element (IRF-E) (21).
The first member of the family, IRF-1, was originally identified as a protein that binds
  • the cis-acting DNA elements in the ifnβ gene promoter and the IRF-E (also referred to as the IFN-stimulated response element; ISRE),
  • in the promoters of IFN-αβ-stimulated genes (22).

IRF-1 is expressed at low basal levels in all cell types examined, but

  • accumulates in response to several stimuli and cytokines including IFN-γ, the strongest IRF-1 inducer (22).
Intensive functional analyses conducted on this transcription factor have revealed a remarkable functional diversity in the
  • regulation of cellular responses through the
  • modulation of different sets of genes,
  • depending on
    1. cell type,
    2. state of the cell, and/or
    3. nature of the stimuli (21).
We and others have shown that IRF-1 affects the differentiation of both lymphoid and myeloid lineages (22, 23, 24, 25, 26, 27, 28). In particular, studies in knockout (KO) mice have implicated IRF-1
in the regulation of various immune processes:
  1. impairment of CD8+ T cell and NK cell maturation,
  2. impaired IL-12 macrophage production,
  3. exclusive Th2 differentiation, and
  4. defective Th1 responses…………. have all been observed (22, 23, 24, 25, 26).
As a result, IRF-1−/− mice are highly susceptible to infections, for which effective host control
    • is associated with a Th1 immune response (24).
In contrast, these mice are characterized by
  • increased resistance to several autoimmune diseases such as
  1. collagen-induced arthritis,
  2. experimental autoimmune encephalomyelitis,
  3. Helicobacter pylori-induced gastritis,
  4. induced lymphocytic thyroiditis,
  5. insulitis, or
  6. diabetes (29, 30, 31, 32).
Recently, we reported that IRF-1−/− mice display a prevalence of
  • dendritic cell (DC) subsets with immature and tolerogenic features that were
    • unable to undergo full maturation after stimulation.
Moreover, IRF-1−/− DC conferred
    • increased suppressive activity to CD4+CD25+ Treg cells (33).
Because there is growing evidence that immature or partially matured DC can induce tolerance (34, 35), we hypothesized that IRF-1 could play a role in
  • Treg development and function.
In this study, we analyzed the CD4+CD25+ compartment in IRF-1−/− mice and
  • we found that in vivo IRF-1 deficiency resulted in a
  • selective and marked increase in highly differentiated and activated CD4+CD25+Foxp3+ Treg cells, whereas
reintroduction of IRF-1 by retrovirus transduction
    • impaired TGF-β-mediated differentiation of IRF-1−/− CD4+CD25− T cells into CD4+CD25+Foxp3+ Treg cells.
At molecular level, we show that IRF-1 plays a direct role in the generation and expansion of CD4+CD25+ Treg cells
    • specifically repressing Foxp3 transcriptional activity.
Our results, therefore, highlight a unique role for IRF-1 as regulator of Foxp3, thus pointing to IRF-1 as a specific tool to control altered tolerance.
Results
CD4+CD25+ Treg from IRF-1−/− mice are increased and functionally more suppressive than WT Treg cells
The distribution and the phenotype of CD4+CD25+Foxp3+ Treg in lymphoid organs of IRF-1−/− mice were determined by flow cytometry.
the number of ex vivo double positive CD4+CD25+ cells was significantly increased in spleens and skin draining and mesenteric lymph nodes (2.8-, 2.3-, and 2.1-fold increase, respectively), and to a lesser extent, in thymus (1.6-fold increase) of IRF-1−/− mice as compared with WT mice. Consistently with previous reports (23, 41), no differences in CD4+ T cell and total cell numbers in all lymphoid organs from WT or IRF-1−/− mice were found (data not shown). Strikingly, intracellular analysis of Foxp3 expression showed that this factor was increasingly expressed in CD4+CD25+ Treg cells from spleens as well as from other lymphoid organs of IRF-1−/− mice
FACS analysis of splenic magnetically sorted CD4+CD25+ Treg cells was performed to evaluate the expression of activation markers.  IRF-1−/− Treg cells were to a large extent characteristic of a marked activated and differentiated phenotype.
Because there is accumulating evidence that activity of CD4+CD25+ Treg cells in vivo involves some immunosuppressive cytokines (9, 10, 11, 12), we also compared the cytokine profile of IRF-1−/− CD4+CD25+ Treg cells with the profile of WT counterparts . Lower levels of proinflammatory cytokines, such as TNF-α and IFN-γ, whereas higher levels of IL-4 were expressed in CD4+CD25+ Treg cells as well as in CD4+CD25− T lymphocytes from KO as compared with WT cells. Notably, only IRF-1−/− Treg cells showed a clear-cut increase in the expression of IL-10. By contrast, TGF-β was expressed at similar levels in CD4+CD25+ Treg cells from both IRF-1−/− and WT mice. Accordingly with mRNA data, IL-10 secretion in supernatants of TCR-stimulated CD4+CD25+ cocultures from IRF-1−/− mice was significantly increased (3-fold), whereas
    • IFN-γ secretion was decreased (2.5-fold) compared with cocultures from WT mice (Fig. 2⇑C).
As the functional hallmark of Treg cells is their ability to suppress the expansion of effector T cells, we next evaluated this activity performing suppression assays (1, 2, 3, 8). Importantly, CD4+CD25+ Treg cells from IRF-1−/− mice were found significantly more efficient than WT Treg cells in suppressing the proliferation of syngeneic CD4+CD25− responder T cells in a dose-dependent fashion. Next, to verify whether IRF-1−/− Treg cells suppression ability was retained vs WT responder T cells, we performed suppression assays using IRF-1−/− Treg and WT responders and vice versa. The suppressive activity of IRF-1−/− Treg cells toward WT responders was dose-dependently increased, as well.
IRF-1−/− CD4+CD25− T cells show high bent to convert into CD4+CD25+ Treg cells
It has been reported in mice and human that TGF-β promotes the induction of peripheral CD4+CD25− T cells into CD4+CD25+ Treg cells (inTreg), that acquire Foxp3 expression and regulatory functions.
In presence of TGF-β, 44.2% of CD4+CD25+ inTreg cells were generated in the coculture of CD4+CD25− T cells from IRF-1−/− mice, whereas
  • only 24% of double positive cells were detected in the corresponding coculture from WT mice.
Notably, even in absence of TGF-β, 25.4% CD4+CD25+ inTreg were generated in the coculture of CD4+CD25− T cells from IRF-1−/− mice, as
  • compared with 16.5% of Treg cells generated in WT cocultures.
Importantly, an increased number of CD4+CD25+-gated Foxp3+ cells were observed in IRF-1−/− inTreg cells in the presence (4.5-fold increase) or in the absence (8-fold increase) of TGF-β compared with WT inTreg cells. Next, to evaluate quantitatively Foxp3 expression levels in TGF-β-induced Treg vs ex vivo freshly purified Treg cells, quantitative real-time PCR was performed. A clear-cut
induction of Foxp3 mRNA (4.5-fold increase) was detected in TGF-β-treated IRF-1−/− cells compared with WT cells. Of note, these levels were comparable with those present in freshly isolated IRF-1−/− CD4+CD25+ cells. Strikingly, also untreated IRF-1−/− T cells showed higher levels of Foxp3 mRNA than WT untreated cells (6-fold increase) and similar to levels present in freshly purified WT CD4+CD25+ Treg cells.
The functionality of CD4+CD25+Foxp3+ inTreg cells was then assessed by suppression assays. TGF-β-treated IRF-1−/− inTreg cells were significantly more effective than the WT counterpart cells
  • in suppressing proliferation of effector T cells in a dose-dependent way.
Interestingly, a saturating amount of anti-IL-10 m Abs neutralized the suppression ability of  inTreg cells from both IRF-1−/− and WT mice even though the effect was much more marked in IRF-1−/− inTreg cells. Control Abs did not exhibit any effect.
Restoring IRF-1 expression in IRF-1−/− CD4+CD25− T cells impairs their differentiation into CD4+CD25+Foxp3+ cells
To address the specificity of IRF-1 role in differentiation of CD4+CD25+ Treg cells from CD25− cells, we investigate whether
  • forced expression of IRF-1 in CD4+CD25− IRF-1−/− T cells could rescue the WT phenotype.
  • bicistronic retroviral vectors expressing murine IRF-1 and human CD8 protein as surface marker (MigR1 IRF-1-CD8) or CD8 alone (MigR1 EV-CD8) were generated.
Splenic CD4+CD25− cells from IRF-1−/− mice were stimulated with plate-bound anti-CD3 and anti-CD28 Abs and infected with either retrovirus.
  • 31.6% of MigR1 EV-CD8 CD4+ retrovirus-infected cells were CD25+, by contrast
  • only 17.7% of MigR1 IRF-1-CD8 retrovirus-infected cells were double positive.
Consistently, Foxp3 expression in CD8+-gated cells was significantly decreased in MigR1 IRF-1-CD8-infected cells as compared with
  • those infected with MigR1 EV-CD8 vectors,
  • strongly supporting the evidence that IRF-1 specifically impairs CD4+CD25+ cell differentiation.
IRF-1 binds an IRF-E on the Foxp3 core promoter and inhibits its transcriptional activity
To shed light on the molecular mechanisms responsible for the striking effect exerted by IRF-1 on the development and function of CD4+CD25+ Treg cells, we investigated whether IRF-1, which is a regulator of key immunomodulatory genes (21), could directly regulate the foxp3 gene promoter activity. The proximal promoter of human foxp3 gene has been recently characterized and localized at −511/+176 bp upstream of the 5′ untranslated region (38). By the Genomatix software, we analyzed this region and found an IRF-E spanning from −234 to −203 bp . This region has been found highly homologous to mouse and rat foxp3 promoter, and of note, the IRF-E is perfectly conserved between humans and these species (38). To determine whether IRF-1 could bind this sequence, DNA affinity purification assays were performed with cell extracts from Jurkat T cells, which display discrete basal levels of IRF-1, and from the same cells treated with IFN-γ to maximally stimulate IRF-1 expression. A total of 200 μg of nuclear extracts was incubated with oligonucleotides containing the WT or the a mutated version of IRF-E. The isolated complexes were then examined by immunoblotting against IRF-1. A specific binding of IRF-1 to Foxp3 oligonucleotide was evident. The binding was strongly stimulated by IFN-γ treatment and, interestingly, it was comparable to that obtained when the same extracts were incubated with a synthetic oligonucleotide corresponding to C13, the canonical IRF-1 consensus sequence (21). IRF-1 binding was highly specific because a mutated version of the Foxp3/IRF-E, or an unrelated oligonucleotide corresponding to the STAT binding site present on the β-casein gene promoter, did not retain any protein from the same extracts. To functionally characterize the specific binding of IRF-1 to the foxp3 gene promoter, we cloned the encompassing part of the proximal promoter containing the IRF-E from −296 to +7 bp of foxp3 gene promoter upstream the luciferase reporter gene. The effect of IRF-1 was evaluated in Jurkat T cells transiently cotransfected with the luciferase reporter gene and increasing doses of an IRF-1-expressing vector.
The results indicated that the basal transcriptional activity of the foxp3 gene promoter
    • was substantially reduced in the presence of IRF-1 and the effect was dose-dependent.
Conversely, the basal activity of the foxp3 gene promoter construct mutated in the IRF-E
    • was not affected by IRF-1 overexpression.
Interestingly, IRF-2, a repressor of IRF-1 transcriptional activity on most promoters (21), neither affected the promoter activity nor counteracted the inhibitory effect exerted by IRF-1.  IRF-1, IRF-2, as well as the IFN-γ treatment drastically reduced the transcriptional activity of the il4 gene promoter, whereas
  • the low molecular mass polypeptide lmp2 construct was stimulated by IRF-1 and by IFN-γ treatment, but it was not affected by IRF-2.

All together these results demonstrate the specificity and functional relevance of IRF-1 binding to the foxp3 proximal promoter.

Foxp3 is a direct target of IRF-1 in human and mouse primary CD4+CD25− T cells and CD4+CD25+ Treg cells
To assess the biological relevance of the the reported effects of IRF-1 on Treg development and on the regulation of Foxp3 expression, we performed experiments with primary cells. We first assessed by Western blot IRF-1 expression levels in CD4+CD25+ Treg cells vs CD4+CD25− T cells magnetically sorted from PBMC of healthy donors or from mice spleens. Strikingly, we found that IRF-1 was down-regulated in double positive cells as compared with CD4+CD25− T cells both in mouse and human primary cells. To determine whether IRF-1 binds the Foxp3 oligonucleotides in primary Treg cells, pull-down assays with the same extracts were then performed. IRF-1 binding to Foxp3 oligonucleotide was significantly decreased in primary CD4+CD25+ Treg cells compared with CD4+CD25− T cells from both species. Foxp3 staining of CD4+CD25− T cells and CD4+CD25+ human Treg cells confirmed that these cells expressed low and high levels of Foxp3, respectively, and
  • Foxp3 expression was further increased by IL-2 treatment.
To test whether IRF-1 expression was also down-modulated during the acquisition of Treg cell phenotype upon TGF-β treatment, freshly purified TCR-activated CD4+CD25− T cells from both species were cultured with TGF-β, or left untreated, for 3 days and Western blot analysis was performed. When cells were cultured in presence of TGF-β, IRF-1 expression was substantially decreased, as compared with untreated cells. Pull-down assays revealed that IRF-1 binding to Foxp3 oligonucleotide was decreased in TGF-β-treated primary cells compared with untreated cells, as well. Consistently, FACS analysis of these cultures indicated that ∼35% of TGF-β-treated CD4+ cells were Foxp3+ in human and ∼10% in mouse TGF-β treated cultures, respectively. By contrast, even though 46.3% of human untreated cells were CD25+ only 5% were Foxp3+.
Next, we assessed the in vivo IRF-1 binding to foxp3 gene in human and mouse primary magnetically sorted CD4+CD25− T cells and CD4+CD25+ Treg cells, using ChIP assay with anti-IRF-1 Abs. After DNA immunoprecipitation, subsequent real-time PCR amplification of the foxp3 gene surrounding the IRF-E site showed significant IRF-1 binding to Foxp3 promoter in CD4+CD25−Foxp3− T cells, and by contrast, a 5-fold decrease of IRF-1 binding in CD4+CD25+Foxp3high human Treg cells (Fig. 6⇑C). Similarly, the binding of IRF-1 to the Foxp3 promoter in the mouse Treg cells was decreased by ∼50%.
Finally, to assess the functionality of the in vivo IRF-1 binding, negatively selected primary human and mouse CD4+ T lymphocytes were nucleofected with the Foxp3 luciferase reporter gene along with expression vector for IRF-1. Fig. 6⇑E shows the results obtained with T cells from three different healthy donors and Fig. 6⇑F shows a representative experiment with mouse T cells from three independent experiments. In all samples, a discrete basal activity of foxp3 gene promoter was present and this activity was significantly repressed by IRF-1.
Discussion
The identification of molecules controlling Treg differentiation and function is important not only in understanding host immune responses in malignancy and autoimmunity but also in shaping immune response.
In this study, we have shown that IRF-1, a transcription factor involved in the IFN signaling, selectively affects CD4+CD25+ Treg cell development and function, unraveling a novel immunoregulatory function of IRF-1 in addition to its well-established role in balancing Th1 vs Th2 type immune responses. Several lines of evidence support this conclusion:
1) IRF-1−/− mice show a selective and marked increase in all lymphoid organs of CD4+CD25+Foxp3+ Treg cells; 2) CD4+CD25+ from IRF-1−/− mice are characterized by a highly activated and differentiated  phenotype and higher levels of Foxp3 that make them to be functionally more suppressive than WT Treg cells;
3) after TGF-β treatment, and importantly also in its absence, CD4+CD25− T cells from KO mice promptly converted into CD4+CD25+Foxp3+ Treg with a higher suppressive activity than WT cells;
4) forced retrovirus-mediated expression of IRF-1 in IRF-1−/− CD4+CD25− T cells impairs their differentiation into CD25+Foxp3+ cells; and 5) IRF-1 directly regulates transcriptional activity of the foxp3 gene promoter.
The phenotypical and functional characteristics of IRF-1−/− Treg cells strongly support the conclusion that IRF-1 can be considered a key negative regulator of CD4+CD25+ Treg cells.
The increased frequency of differentiated and activated CD4+CD25+ Treg cells characterized by an immunosuppressive cytokine profile described in this study
    • may provide a mechanistic base for the reduced incidence and severity of several autoimmune diseases characterizing IRF-1−/− mice .
In this regard, it has been recently shown that CD4+CD25+ Treg cells were increased in IRF-1−/− mice backcrossed with the MRL/lpr mice, which showed reduced glomerulonephritis.
The increased production of the immunosuppressive cytokine IL-10 by isolated Treg cells from IRF-1−/− mice and the reverted suppression ability of inTreg by anti-IL-10 Abs suggest that this cytokine could play a key role in their suppressor function. Consistently, IL-10 activity has been recently associated with the function of TGF-β-induced CD4+CD25−CD45RBlow cells because their suppressive activity was abrogated with anti-IL-10R Ab treatment (13). Moreover, several reports focused on the in vivo IL-10 role in peripheral CD4+CD25+ Treg cell function in various autoimmunity models (10, 11, 12), although IL-10 seems not required for the functions of thymically derived Treg cells (1). In contrast with the increased IL-10 production, T cells from IRF-1−/− mice failed to produce significant amounts of proinflammatory cytokines such as IFN-γ or TNF-α. Accordingly, an inverse relationship between in vivo IFN-γ administration and generation or activation of CD4+CD25+ Treg cells has been recently shown (45). Moreover, in humans, it has been reported that TNF-α inhibits the suppressive function of both naturally occurring CD4+CD25+ Treg and TGF-β-induced Treg cells, and an anti-TNF Ab therapy reversed their suppressive activity by down-modulating the expression of Foxp3 (46). These latter and our results are apparently in contrast with what was recently reported on the stimulating role of IFN-γ on Foxp3 induction and conversion of CD4+CD25− T cells to CD4+ Treg cells in the IFN-γ KO model (47). In this regard, it is noteworthy to underline that, as it has been also suggested, although knocking down genes involved in up-regulation of IFN-γ expression do not significantly influence autoimmunity, by contrast the absence of genes expressed in response to IFN-γ, including IRF-1, lead to greatly reduced autoimmunity (48). Thus, although the exact mechanism underlying IFN-γ and TNF-α interference with the elicitation of Treg cells remains to be defined, we can speculate that induction of IRF-1 expression, which is up-regulated by IFN-γ and TNF-α, may represent a mechanism through which proinflammatory cytokines negatively affect Foxp3 expression, thereby influencing generation or activation of CD4+CD25+ Treg cells.
It is well known that Foxp3 plays a pivotal role in the regulatory functions of CD4+CD25+ T cells both in humans and in animal models. Thus, the key question in the field of Treg biology is which are molecules and signals that govern Foxp3 transcription.
We identify Foxp3 as specific target of IRF-1 and we show
    • that it binds to foxp3 gene promoter in vitro and in vivo and represses its expression.
Structure of the human foxp3 gene promoter and elements necessary for its induction in T cells have been reported. We have identified an IRF-E sequence at 203 bp upstream of the transcriptional start site that is highly conserved. This element is bound by IRF-1 as proven by pull-down experiments and by ChIP analysis in intact cells, and IRF-1 binding resulted in a specific,
  • dose-dependent repression of the foxp3 proximal promoter.
Notably, treatments with IFN-γ, a major IRF-1 inducer, significantly inhibited foxp3 gene promoter transcriptional activity, whereas IRF-2 did not have any effects. It is noteworthy that the foxp3 gene is highly conserved between mouse and man species, and in particular, the core promoter and the IRF-E identified in this study are perfectly conserved between mouse and human. Such conservation underscores the importance of this motif as regulatory element and provides additional evidence for the role of IRF-1 in regulating foxp3 gene expression.  IRF-1 binds this sequence and negatively regulates its expression in both human and mouse cells. The molecular interactions enabling IRF-1 to inhibit Foxp3 are not yet identified, although our preliminary results show that IRF-1 may compete with c-Myb for the binding to the same overlapping consensus sequence on the foxp3 gene promoter.
In summary, the current study provides evidence that IRF-1 affects CD4+CD25+ development and function by Foxp3 repression. Thus, our data demonstrate a new important contribution by which IRF-1 affects T cell differentiation and provide new important insights into molecular mechanisms controlling immune homeostasis.


Th1-Th2-Th17-Treg origin

Th1-Th2-Th17-Treg origin (Photo credit: Wikipedia)

 

Read Full Post »

Lipoxin A4 Regulates Natural Killer Cell in Asthma

Reporter: Larry H Bernstein, MD, FCAP

Lipoxin A4 Regulates Natural Killer Cell and Type 2 Innate Lymphoid Cell Activation in Asthma
 C Barnig, M Cernadas, S Dutile,…BR Levy.
Sci Transl Med  27 Feb 2013. ; 5(174): p. 174ra26  SciTranslMed.             http://dx.doi.org/10.1126/scitranslmed.3004812
Asthma is a prevalent disease of chronic inflammation in which
  • endogenous counterregulatory signaling pathways are dysregulated.
Recent evidence suggests that innate lymphoid cells (ILCs), including
  • natural killer (NK) cells and
  • type 2 ILCs (ILC2s),
    • can participate in the regulation of allergic airway responses,
    • in particular airway mucosal inflammation.
Sci Transl Med 27 February 2013:  5(174) 174ra26        http://dx.doi.org/10.1126/scitranslmed.3004812
Both NK cells and ILC2s expressed
  • the pro-resolving ALX/FPR2 receptors.
Lipoxin A4, a natural pro-resolving ligand for ALX/FPR2 receptors, significantly
  • increased NK cell–mediated eosinophil apoptosis and
  • decreased IL-13 release by ILC2s.
Together, these findings indicate that ILCs are targets for lipoxin A4
  • to decrease airway inflammation and mediate the catabasis of eosinophilic inflammation

Molecular biology for formyl peptide receptors in human diseases
Yongsheng Li , 

Leukocytes accumulate at sites of inflammation and immunological reaction in response to locally existing chemotactic mediators. The first chemotactic factors structurally defined were N-formyl peptides. Subsequently, numerous ligands were identified

FPRs interact with this menagerie of structurally diverse pro- and anti-inflammatory ligands to possess important regulatory effects in multiple diseases, including

  1. inflammation,
  2. amyloidosis,
  3. Alzheimer’s disease,
  4. prion disease,
  5. acquired immunodeficiency syndrome,
  6. obesity,
  7. diabetes, and
  8. cancer.

How these receptors recognize diverse ligands and how they contribute to disease pathogenesis and host defense are basic questions currently under investigation that

    • would open up new avenues for the future management of inflammation-related diseases.

FPR2/ALX receptor expression and internalization are critical for lipoxin A4 and annexin-derived peptide-stimulated phagocytosis 
PMaderna, DC Cottell, T Toivonen, N Dufton, J Dalli, M Perretti and C Godson
The FASEB Journal Nov 2010; 24 (11): 4240-4249      Published online June 22, 2010, http://dx.doi.org/10.1096/fj.10-159913

Lipoxins (LXs) are endogenously produced eicosanoids with well-described anti-inflammatory and proresolution activities,

  • stimulating nonphlogistic phagocytosis of apoptotic cells by macrophages.

LXA4 and the glucocorticoid-derived annexin A1 peptide (Ac2–26) bind to a common G-protein-coupled receptor, termed FPR2/ALX. However, direct evidence of the involvement of FPR2/ALX in the anti-inflammatory and proresolution activity of LXA4 is still to be investigated. Here we describe FPR2/ALX trafficking in response to LXA4 and Ac2–26 stimulation. We have transfected cells with HA-tagged FPR2/ALX and studied receptor trafficking in unstimulated, LXA4 (1–10 nM)- and Ac2–26 (30 μM)-treated cells using multiple approaches that include immunofluorescent confocal microscopy, immunogold labeling of cryosections, and ELISA and investigated receptor trafficking in agonist-stimulated phagocytosis. We conclude that PKC-dependent internalization of FPR2/ALX is required for phagocytosis. Using bone marrow-derived macrophages (BMDMs) from mice in which the FPR2/ALX ortholog Fpr2 had been deleted, we observed

  • the nonredundant function for this receptor in LXA4 and Ac2–26 stimulated phagocytosis of apoptotic neutrophils.
  1. LXA4 stimulated phagocytosis 1.7-fold above basal (P<0.001) by BMDMs from wild-type mice, whereas no effect was found on BMDMs from Fpr2−/− mice.
  2. Ac2–26 stimulates phagocytosis by BMDMs from wild-type mice 1.5-fold above basal (P<0.05), but  Ac2–26 failed to stimulate phagocytosis by BMDMs isolated from Fpr2−/− mice.

These data reveal novel and complex mechanisms of the FPR2/ALX receptor trafficking and functionality in the resolution of inflammation.—
Maderna, P., Cottell, D. C., Toivonen, T., Dufton, N., Dalli, J., Perretti, M., Godson, C.
http://www.FASEB.j.org/FPR2/ALX receptor expression and internalization are critical for lipoxin A4 and annexin-derived peptide-stimulated phagocytosis.
We have transfected cells with HA-tagged FPR2/ALX and studied receptor trafficking in unstimulated, LXA4 (1–10 nM)- and Ac2–26 (30 μM)-treated cells using multiple approaches and conclude that PKC-dependent internalization of FPR2/ALX is required for phagocytosis. Using bone marrow-derived macrophages (BMDMs) from mice in which the FPR2/ALX ortholog Fpr2 had been deleted,

  • we observed the nonredundant function for this receptor in LXA4 and Ac2–26 stimulated phagocytosis of apoptotic neutrophils.

LXA4 stimulated phagocytosis 1.7-fold above basal (P<0.001) by BMDMs from wild-type mice,

  • whereas no effect was found on BMDMs from Fpr2−/− mice.

Ac2–26 stimulates phagocytosis by BMDMs from wild-type mice 1.5-fold above basal (P<0.05)

  •  Ac2–26 failed to stimulate phagocytosis by BMDMs isolated from Fpr2−/− mice relative to vehicle.

These data reveal novel and complex mechanisms of the FPR2/ALX receptor trafficking and functionality in the resolution of inflammation.
The lipoxin receptor ALX: potent ligand-specific and stereoselective actions in vivo.
Chiang, N., Serhan, CN, Dahlen, SE, Drazen, JM, Hay, DW, Rovati, GE, et al.
Pharmacol. Rev. 2006; 58, 463–487.      http://www.PharmacolRev.com/The_lipoxin_receptor_ALX:_potent_ligand_specific_and_stereoselective_actions_in_vivo/

Asthma Obstruction of the lumen of the bronchi...

Asthma Obstruction of the lumen of the bronchiole by mucoid exudate, goblet cell metaplasia, epithelial basement membrane thickening and severe inflammation of bronchiole. (Photo credit: Wikipedia)

Schematic diagram indicating the complementary...

Schematic diagram indicating the complementary activities of cytotoxic T-cells and NK cells. (Photo credit: Wikipedia)

Related articles

 

Read Full Post »

Curator/Reporter Aviral Vatsa PhD, MBBS

Based on: A review by (Wink et al., 2011)

This post is in continuation to Part 1 by the same title.

In part one I covered the basics of role of redox chemistry in immune reactions, the phagosome cauldron, and how bacteria bacteria, virus and parasites trigger the complex pathway of NO production and its downstream effects. While we move further in this post, the previous post can be accessed here.

REDOX REGULATION OF IMMUNE FUNCTION

Regulation of the redox immunomodulators—NO/RNS and ROS

In addition to eradicating pathogens, NO/RNS and ROS and their chemical interactions act as effective immunomodulators that regulate many cellular metabolic pathways and tissue repair and proinflammatory pathways. Figure 3 shows these pathways.

Figure 3. Schematic overview of interactive connections between NO and ROS-mediated metabolic pathways. Credit: (Wink et al., 2011)

Regulation of iNOS enzyme activity is critical to NO production. Factors such as the availability of arginine, BH4, NADPH, and superoxide affect iNOS activity and thus NO production. In the absence of arginine and BH4 iNOS becomes a O2_/H2O2 generator (Vásquez-Vivar et al., 1999). Hence metabolic pathways that control arginine and BH4 play a role in determining the NO/superoxide balance. Arginine levels in cells depend on various factors such as type of uptake mechanisms that determine its spatial presence in various compartments and enzymatic systems. As shown in Fig3 Arginine is the sole substrate for iNOS and arginase. Arginase is another key enzyme in immunemodulation. AG is also regulated by NOS and NOX activities. NOHA, a product of NOS, inhibits AG, and O2–increases AG activity. Importantly, high AG activity is associated with elevated ROS and low NO fluxes. NO antagonises NOX2 assembly that in turn leads to reduction in O2_ production. NO also inhibits COX2 activity thus reducing ROS production. Thus, as NO levels decline, oxidative mechanisms increase. Oxidative and nitrosative stress can also decrease intracellular GSH (reduced form) levels, resulting in a reduced antioxidant capability of the cell.

Immune-associated redox pathways regulate other important metabolic cell functions that have the potential for widespread impact on cells, organs, and organisms. These pathways, such as mediated via methionine and polyamines, are critical for DNA stabilization, cell proliferation, and membrane channel activity, all of which are also involved in immune-mediated repair processes.

NO levels dictate the immune signaling pathway

NO/RNS and ROS actively control innate and adaptive immune signaling by participating in induction, maintenance, and/or termination of proinflammatory and anti-inflammatory signaling. As in pathogen eradication, the temporal and spatial concentration profiles of NO are key factors in determining immune-mediated processes.

Brune and coworkers (Messmer et al., 1994) first demonstrated that p53 expression was associated with the concentrations of NO that led to apoptosis in macrophages. Subsequent studies linked NO concentration profiles with expression of other key signaling proteins such as HIF-1α and Akt-P (Ridnour et al., 2008; Thomas et al., 2008). Various levels of NO concentrations trigger different pathways and expectedly this concentration-dependent profile varies with distance from the NO source.NO is highly diffucible and this characteristic can result in 1000 fold reduction in concentration within one cell length distance travelled from the source of production. Time course studies have also shown alteration in effects of same levels of NO over time e.g. NO-mediated ERK-P levels initially increased rapidly on exposure to NO donors and then decreased with continued NO exposure (Thomas et al., 2004), however HIF-1α levels remained high as long as NO levels were elevated. Thus some of the important factors that play critical role in NO effects are: distance from source, NO concentrations, duration of exposure, bioavailability of NO, and production/absence of other redox molecules.

Figure and legend credits: (Wink et al., 2011)

Fig 4: The effect of steady-state flux of NO on signal transduction mechanisms.

This diagram represents the level of sustained NO that is required to activate specific pathways in tumor cells. Similar effects have been seen on endothelial cells. These data were generated by treating tumor or endothelial cells with the NO donor DETANO (NOC-18) for 24 h and then measuring the appropriate outcome measures (for example, p53 activation). Various concentrations of DETANO that correspond to cellular levels of NO are: 40–60 μM DETANO = 50 nM NO; 80–120 μM DETANO = 100 nM NO; 500 μM DETANO = 400 nM NO; and 1 mM DETANO = 1 μM NO. The diagram represents the effect of diffusion of NO with distance from the point source (an activated murine macrophage producing iNOS) in vitro (Petri dish) generating 1 μM NO or more. Thus, reactants or cells located at a specific distance from the point source (i.e., iNOS, represented by star) would be exposed to a level of NO that governs a specific subset of physiological or pathophysiological reactions. The x-axis represents the different zone of NO-mediated events that is experienced at a specific distance from a source iNOS producing >1 μM. Note: Akt activation is regulated by NO at two different sites and by two different concentration levels of NO.

Species-specific NO production

The relationship of NO and immunoregulation has been established on the basis of studies on tumor cell lines or rodent macrophages, which are readily available sources of NO. However in humans the levels of protein expression for NOS enzymes and the immune induction required for such levels of expression are quite different than in rodents (Weinberg, 1998). This difference is most likely due to the human iNOS promotor rather than the activity of iNOS itself. There is a significant mismatch between the promoters of humans and rodents and that is likely to account for the notable differences in the regulation of gene induction between them. The combined data on rodent versus human NO and O2– production strongly suggest that in general, ROS production is a predominant feature of activated human macrophages, neutrophils, and monocytes, and the equivalent murine immune cells generate a combination of O2– and NO and in some cases, favor NO production. These differences may be crucial to understanding how immune responses are regulated in a species-specific manner. This is particularly useful, as pathogen challenges change constantly.

The next post in this series will cover the following topics:

The impact of NO signaling on an innate immune response—classical activation

NO and proinflammatory genes

NO and regulation of anti-inflammatory pathways

NO impact on adaptive immunity—immunosuppression and tissue-restoration response

NO and revascularization

Acute versus chronic inflammatory disease

Bibliography

1. Wink, D. A. et al. Nitric oxide and redox mechanisms in the immune response. J Leukoc Biol 89, 873–891 (2011).

2. Vásquez-Vivar, J. et al. Tetrahydrobiopterin-dependent inhibition of superoxide generation from neuronal nitric oxide synthase. J. Biol. Chem. 274, 26736–26742 (1999).

3. Messmer, U. K., Ankarcrona, M., Nicotera, P. & Brüne, B. p53 expression in nitric oxide-induced apoptosis. FEBS Lett. 355, 23–26 (1994).

4. Ridnour, L. A. et al. Molecular mechanisms for discrete nitric oxide levels in cancer. Nitric Oxide 19, 73–76 (2008).

5. Thomas, D. D. et al. The chemical biology of nitric oxide: implications in cellular signaling. Free Radic. Biol. Med. 45, 18–31 (2008).

6. Thomas, D. D. et al. Hypoxic inducible factor 1alpha, extracellular signal-regulated kinase, and p53 are regulated by distinct threshold concentrations of nitric oxide. Proc. Natl. Acad. Sci. U.S.A. 101, 8894–8899 (2004).

7. Weinberg, J. B. Nitric oxide production and nitric oxide synthase type 2 expression by human mononuclear phagocytes: a review. Mol. Med. 4, 557–591 (1998).

Further reading on NO:

Nitric Oxide in bone metabolism July 16, 2012

Author: Aviral Vatsa PhD, MBBS

http://pharmaceuticalintelligence.com/2012/07/16/nitric-oxide-in-bone-metabolism/?goback=%2Egde_4346921_member_134751669

Nitric Oxide production in Systemic sclerosis July 25, 2012

Curator: Aviral Vatsa, PhD, MBBS

http://pharmaceuticalintelligence.com/2012/07/25/nitric-oxide-production-in-systemic-sclerosis/?goback=%2Egde_4346921_member_138370383

Nitric Oxide Signalling Pathways August 22, 2012 by

Curator/ Author: Aviral Vatsa, PhD, MBBS

http://pharmaceuticalintelligence.com/2012/08/22/nitric-oxide-signalling-pathways/?goback=%2Egde_4346921_member_151245569

Nitric Oxide: a short historic perspective August 5, 2012

Author/Curator: Aviral Vatsa PhD, MBBS

http://pharmaceuticalintelligence.com/2012/08/05/nitric-oxide-a-short-historic-perspective-7/

Nitric Oxide: Chemistry and function August 10, 2012

Curator/Author: Aviral Vatsa PhD, MBBS

http://pharmaceuticalintelligence.com/2012/08/10/nitric-oxide-chemistry-and-function/?goback=%2Egde_4346921_member_145137865

Nitric Oxide and Platelet Aggregation August 16, 2012 by

Author: Dr. Venkat S. Karra, Ph.D.

http://pharmaceuticalintelligence.com/2012/08/16/no-and-platelet-aggregation/?goback=%2Egde_4346921_member_147475405

The rationale and use of inhaled NO in Pulmonary Artery Hypertension and Right Sided Heart Failure August 20, 2012

Author: Larry Bernstein, MD

http://pharmaceuticalintelligence.com/2012/08/20/the-rationale-and-use-of-inhaled-no-in-pulmonary-artery-hypertension-and-right-sided-heart-failure/

Nitric Oxide: The Nobel Prize in Physiology or Medicine 1998 Robert F. Furchgott, Louis J. Ignarro, Ferid Murad August 16, 2012

Reporter: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/08/16/nitric-oxide-the-nobel-prize-in-physiology-or-medicine-1998-robert-f-furchgott-louis-j-ignarro-ferid-murad/

Coronary Artery Disease – Medical Devices Solutions: From First-In-Man Stent Implantation, via Medical Ethical Dilemmas to Drug Eluting Stents August 13, 2012

Author: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/08/13/coronary-artery-disease-medical-devices-solutions-from-first-in-man-stent-implantation-via-medical-ethical-dilemmas-to-drug-eluting-stents/

Nano-particles as Synthetic Platelets to Stop Internal Bleeding Resulting from Trauma

August 22, 2012

Reported by: Dr. V. S. Karra, Ph.D.

http://pharmaceuticalintelligence.com/2012/08/22/nano-particles-as-synthetic-platelets-to-stop-internal-bleeding-resulting-from-trauma/

Cardiovascular Disease (CVD) and the Role of agent alternatives in endothelial Nitric Oxide Synthase (eNOS) Activation and Nitric Oxide Production July 19, 2012

Curator and Research Study Originator: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/07/19/cardiovascular-disease-cvd-and-the-role-of-agent-alternatives-in-endothelial-nitric-oxide-synthase-enos-activation-and-nitric-oxide-production/

Macrovascular Disease – Therapeutic Potential of cEPCs: Reduction Methods for CV Risk

July 2, 2012

An Investigation of the Potential of circulating Endothelial Progenitor Cells (cEPCs) as a Therapeutic Target for Pharmacological Therapy Design for Cardiovascular Risk Reduction: A New Multimarker Biomarker Discovery

Curator: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/07/02/macrovascular-disease-therapeutic-potential-of-cepcs-reduction-methods-for-cv-risk/

Bone remodelling in a nutshell June 22, 2012

Author: Aviral Vatsa, Ph.D., MBBS

http://pharmaceuticalintelligence.com/2012/06/22/bone-remodelling-in-a-nutshell/

Targeted delivery of therapeutics to bone and connective tissues: current status and challenges- Part, September  

Author: Aviral Vatsa, PhD, September 23, 2012

http://pharmaceuticalintelligence.com/2012/09/23/targeted-delivery-of-therapeutics-to-bone-and-connective-tissues-current-status-and-challenges-part-i/

Calcium dependent NOS induction by sex hormones: Estrogen

Curator: S. Saha, PhD, October 3, 2012

http://pharmaceuticalintelligence.com/2012/10/03/calcium-dependent-nos-induction-by-sex-hormones/

Nitric Oxide and Platelet Aggregation,

Author V. Karra, PhD, August 16, 2012

http://pharmaceuticalintelligence.com/2012/08/16/no-and-platelet-aggregation/

Bystolic’s generic Nebivolol – positive effect on circulating Endothelial Progenitor Cells endogenous augmentation

Curator: Aviva Lev-Ari, PhD, July 16, 2012

http://pharmaceuticalintelligence.com/?s=Nebivolol

Endothelin Receptors in Cardiovascular Diseases: The Role of eNOS Stimulation

Author: Aviva Lev-Ari, PhD, 10/4/2012

http://pharmaceuticalintelligence.com/2012/10/04/endothelin-receptors-in-cardiovascular-diseases-the-role-of-enos-stimulation/

Inhibition of ET-1, ETA and ETA-ETB, Induction of NO production, stimulation of eNOS and Treatment Regime with PPAR-gamma agonists (TZD): cEPCs Endogenous Augmentation for Cardiovascular Risk Reduction – A Bibliography

Curator: Aviva Lev-Ari, 10/4/2012.

http://pharmaceuticalintelligence.com/2012/10/04/inhibition-of-et-1-eta-and-eta-etb-induction-of-no-production-and-stimulation-of-enos-and-treatment-regime-with-ppar-gamma-agonists-tzd-cepcs-endogenous-augmentation-for-cardiovascular-risk-reduc/

Nitric Oxide Nutritional remedies for hypertension and atherosclerosis. It’s 12 am: do you know where your electrons are?

Author and Reporter: Meg Baker, 10/7/2012.

http://pharmaceuticalintelligence.com/2012/10/07/no-nutritional-remedies-for-hypertension-and-atherosclerosis-its-12-am-do-you-know-where-your-electrons-are/

Read Full Post »

Curator and Reporter: Aviral Vatsa PhD, MBBS

Based on: A review by Wink et al., 2011

This is the first part of a two part post

Nitric oxide (NO), reactive nitrogen species (RNS) and reactive oxygen species (ROS) perform dual roles as immunotoxins and immunomodulators. An incoming immune signal initiates NO and ROS production both for tackling the pathogens and modulating the downstream immune response via complex signaling pathways. The complexity of these interactions is a reflection of involvement of redox chemistry in biological setting (fig. 1)

Fig 1. Image credit: (Wink et al., 2011)

Previous studies have highlighted the role of NO in immunity. It was shown that macrophages released a substance that had antitumor and antipathogen activity and required arginine for its production (Hibbs et al., 1987, 1988). Hibbs and coworkers further strengthened the connection between immunity and NO by demonstrating that IL2 mediated immune activation increased NO levels in patients and promoted tumor eradication in mice (Hibbs et al., 1992; Yim et al., 1995).

In 1980s a number of authors showed the direct evidence that macrophages made nitrite, nitrates and nitrosamines. It was also shown that NO generated by macrophages could kill leukemia cells (Stuehr and Nathan, 1989). Collectively these studies along with others demonstrated the important role NO plays in immunity and lay the path for further research in understanding the role of redox molecules in immunity.

NO is produced by different forms of nitric oxide synthase (NOS) enzymes such as eNOS (endothelial), iNOS (inducible) and nNOS (neuronal). The constitutive forms of eNOS generally produce NO in short bursts and in calcium dependent manner. The inducible form produces NO for longer durations and is calcium independent. In immunity, iNOS plays a vital role. NO production by iNOS can occur over a wide range of concentrations from as little as nM to as much as µM. This wide range of NO concentrations provide iNOS with a unique flexibility to be functionally effective in various conditions and micro-environements and thus provide different temporal and concentration profiles of NO, that can be highly efficient in dealing with immune challenges.

Redox reactions in immune responses

NO/RNS and ROS are two categories of molecules that bring about immune regulation and ‘killing’ of pathogens. These molecules can perform independently or in combination with each other. NO reacts directly with transition metals in heme or cobalamine, with non-heme iron, or with reactive radicals (Wink and Mitchell, 1998). The last reactivity also imparts it a powerful antioxidant capability. NO can thus act directly as a powerful antioxidant and prevent injury initiated by ROS (Wink et al., 1999). On the other hand, NO does not react directly with thiols or other nucleophiles but requires activation with superoxide to generate RNS. The RNS species then cause nitrosative and oxidative stress (Wink and Mitchell, 1998).

The variety of functions achieved by NO can be understood if one looks at certain chemical concepts. NO and NO2 are lipophilic and thus can migrate through cells, thus widening potential target profiles. ONOO-, a RNS, reacts rapidly with CO2 that shortens its half life to <10 ms. The anionic form and short half life limits its mobility across membranes. When NO levels are higher than superoxide levels, the CO2-OONOintermediate is converted to NO2 and N2O3 and changes the redox profile from an oxidative to a nitrosative microenvironment. The interaction of NO and ROS determines the bioavailability of NO and proximity of RNS generation to superoxide source, thus defining a reaction profile. The ROS also consumes NO to generate NO2 and N2O3 as well as nitrite in certain locations. The combination of these reactions in different micro-environments provides a vast repertoire of reaction profiles for NO/RNS and ROS entities.

The Phagosome ‘cauldron’

The phagosome provides an ‘isolated’ environment for the cell to carry out foreign body ‘destruction’. ROS, NO and RNS interact to bring about redox reactions. The concentration of NO in a phagosome can depend on the kind of NOS in the vicinity and its activity and other localised cellular factors. NO and is metabolites such as nitrites and nitrates along with ROS combine forces to kill pathogens in the acidic environment of the phagosome as depicted in the figure 2 below.

Fig 2. The NO chemistry of the phagosome. (image credit: (Wink et al., 2011)

This diagram depicts the different nitrogen oxide and ROS chemistry that can occur within the phagosome to fight pathogens. The presence of NOX2 in the phagosomes serves two purposes: one is to focus the nitrite accumulation through scavenging mechanisms, and the second provides peroxide as a source of ROS or FA generation. The nitrite (NO2−) formed in the acidic environment provides nitrosative stress with NO/NO2/N2O3. The combined acidic nature and the ability to form multiple RNS and ROS within the acidic environment of the phagosome provide the immune response with multiple chemical options with which it can combat bacteria.

Bacteria

There are various ways in which NO combines forces with other molecules to bring about bacterial killing. Here are few examples

E.coli: It appears to be resistant to individual action of NO/RNS and H2O2 /ROS. However, when combined together, H2O2 plus NO mediate a dramatic, three-log increase in cytotoxicity, as opposed to 50% killing by NO alone or H2O2 alone. This indicates that these bacteria are highly susceptible to their synergistic action.

Staphylococcus: The combined presence of NO and peroxide in staphylococcal infections imparts protective effect. However, when these bacteria are first exposed to peroxide and then to NO there is increased toxicity. Hence a sequential exposure to superoxide/ROS and then NO is a potent tool in eradicating staphylococcal bacteria.

Mycobacterium tuberculosis: These bacterium are sensitive to NO and RNS, but in this case, NO2 is the toxic species. A phagosome microenvironment consisting of ROS combined with acidic nitrite generates NO2/N2O3/NO, which is essential for pathogen eradication by the alveolar macrophage. Overall, NO has a dual function; it participates directly in killing an organism, and/or it disarms a pathway used by that organism to elude other immune responses.

Parasites

Many human parasites have demonstrated the initiation of the immune response via the induction of iNOS, that then leads to expulsion of the parasite. The parasites include Plasmodia(malaria), Leishmania(leishmaniasis), and Toxoplasma(toxoplasmosis). Severe cases of malaria have been related with increased production of NO. High levels of NO production are however protective in these cases as NO was shown to kill the parasites (Rockett et al., 1991; Gyan et al., 1994). Leishmania is an intracellualr parasite that resides in the mamalian macrophages. NO upregulation via iNOS induction is the primary pathway involved in containing its infestation. A critical aspect of NO metabolism is that NOHA inhibits AG activity, thereby limiting the growth of parasites and bacteria including Leishmania, Trypanosoma, Schistosoma, HelicobacterMycobacterium, and Salmonella, and is distinct from the effects of RNS. Toxoplasma gondii is also an intracellular parasite that elicits NO mediated response. INOS knockout mice have shown more severe inflammatory lesions in the CNS that their wild type counterparts, in response to toxoplasma exposure. This indicates the CNS preventative role of iNOS in toxoplasmosis (Silva et al., 2009).

Virus

Viral replication can be checked by increased production of NO by induction of iNOS (HIV-1, coxsackievirus, influenza A and B, rhino virus, CMV, vaccinia virus, ectromelia virus, human herpesvirus-1, and human parainfluenza virus type 3) (Xu et al., 2006). NO can reduce viral load, reduce latency and reduce viral replication. One of the main mechanisms as to how NO participates in viral eradication involves the nitrosation of critical cysteines within key proteins required for viral infection, transcription, and maturation stages. For example, viral proteases or even the host caspases that contain cysteines in their active site are involved in the maturation of the virus. The nitrosative stress environment produced by iNOS may serve to protect against some viruses by inhibiting viral infectivity, replication, and maturation.

To be continued in part 2 …

Bibliography

Gyan, B., Troye-Blomberg, M., Perlmann, P., Björkman, A., 1994. Human monocytes cultured with and without interferon-gamma inhibit Plasmodium falciparum parasite growth in vitro via secretion of reactive nitrogen intermediates. Parasite Immunol. 16, 371–3

Hibbs, J.B., Jr, Taintor, R.R., Vavrin, Z., 1987. Macrophage cytotoxicity: role for L-arginine deiminase and imino nitrogen oxidation to nitrite. Science 235, 473–476.

Hibbs, J.B., Jr, Taintor, R.R., Vavrin, Z., Rachlin, E.M., 1988. Nitric oxide: a cytotoxic activated macrophage effector molecule. Biochem. Biophys. Res. Commun. 157, 87–94.

Hibbs, J.B., Jr, Westenfelder, C., Taintor, R., Vavrin, Z., Kablitz, C., Baranowski, R.L., Ward, J.H., Menlove, R.L., McMurry, M.P., Kushner, J.P., 1992. Evidence for cytokine-inducible nitric oxide synthesis from L-arginine in patients receiving interleu

Rockett, K.A., Awburn, M.M., Cowden, W.B., Clark, I.A., 1991. Killing of Plasmodium falciparum in vitro by nitric oxide derivatives. Infect Immun 59, 3280–3283.

Stuehr, D.J., Nathan, C.F., 1989. Nitric oxide. A macrophage product responsible for cytostasis and respiratory inhibition in tumor target cells. J. Exp. Med. 169, 1543–1555.

Wink, D.A., Hines, H.B., Cheng, R.Y.S., Switzer, C.H., Flores-Santana, W., Vitek, M.P., Ridnour, L.A., Colton, C.A., 2011. Nitric oxide and redox mechanisms in the immune response. J Leukoc Biol 89, 873–891.

Wink, D.A., Mitchell, J.B., 1998. Chemical biology of nitric oxide: Insights into regulatory, cytotoxic, and cytoprotective mechanisms of nitric oxide. Free Radic. Biol. Med. 25, 434–456.

Wink, D.A., Vodovotz, Y., Grisham, M.B., DeGraff, W., Cook, J.C., Pacelli, R., Krishna, M., Mitchell, J.B., 1999. Antioxidant effects of nitric oxide. Meth. Enzymol. 301, 413–424.

Xu, W., Zheng, S., Dweik, R.A., Erzurum, S.C., 2006. Role of epithelial nitric oxide in airway viral infection. Free Radic. Biol. Med. 41, 19–28.

Yim, C.Y., McGregor, J.R., Kwon, O.D., Bastian, N.R., Rees, M., Mori, M., Hibbs, J.B., Jr, Samlowski, W.E., 1995. Nitric oxide synthesis contributes to IL-2-induced antitumor responses against intraperitoneal Meth A tumor. J. Immunol. 155, 4382–4390.

Further reading on NO:

Nitric Oxide in bone metabolism July 16, 2012

Author: Aviral Vatsa PhD, MBBS

http://pharmaceuticalintelligence.com/2012/07/16/nitric-oxide-in-bone-metabolism/?goback=%2Egde_4346921_member_134751669

Nitric Oxide production in Systemic sclerosis July 25, 2012

Curator: Aviral Vatsa, PhD, MBBS

http://pharmaceuticalintelligence.com/2012/07/25/nitric-oxide-production-in-systemic-sclerosis/?goback=%2Egde_4346921_member_138370383

Nitric Oxide Signalling Pathways August 22, 2012 by

Curator/ Author: Aviral Vatsa, PhD, MBBS

http://pharmaceuticalintelligence.com/2012/08/22/nitric-oxide-signalling-pathways/?goback=%2Egde_4346921_member_151245569

Nitric Oxide: a short historic perspective August 5, 2012

Author/Curator: Aviral Vatsa PhD, MBBS

http://pharmaceuticalintelligence.com/2012/08/05/nitric-oxide-a-short-historic-perspective-7/

Nitric Oxide: Chemistry and function August 10, 2012

Curator/Author: Aviral Vatsa PhD, MBBS

http://pharmaceuticalintelligence.com/2012/08/10/nitric-oxide-chemistry-and-function/?goback=%2Egde_4346921_member_145137865

Nitric Oxide and Platelet Aggregation August 16, 2012 by

Author: Dr. Venkat S. Karra, Ph.D.

http://pharmaceuticalintelligence.com/2012/08/16/no-and-platelet-aggregation/?goback=%2Egde_4346921_member_147475405

The rationale and use of inhaled NO in Pulmonary Artery Hypertension and Right Sided Heart Failure August 20, 2012

Author: Larry Bernstein, MD

http://pharmaceuticalintelligence.com/2012/08/20/the-rationale-and-use-of-inhaled-no-in-pulmonary-artery-hypertension-and-right-sided-heart-failure/

Nitric Oxide: The Nobel Prize in Physiology or Medicine 1998 Robert F. Furchgott, Louis J. Ignarro, Ferid Murad August 16, 2012

Reporter: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/08/16/nitric-oxide-the-nobel-prize-in-physiology-or-medicine-1998-robert-f-furchgott-louis-j-ignarro-ferid-murad/

Coronary Artery Disease – Medical Devices Solutions: From First-In-Man Stent Implantation, via Medical Ethical Dilemmas to Drug Eluting Stents August 13, 2012

Author: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/08/13/coronary-artery-disease-medical-devices-solutions-from-first-in-man-stent-implantation-via-medical-ethical-dilemmas-to-drug-eluting-stents/

Nano-particles as Synthetic Platelets to Stop Internal Bleeding Resulting from Trauma

August 22, 2012

Reported by: Dr. V. S. Karra, Ph.D.

http://pharmaceuticalintelligence.com/2012/08/22/nano-particles-as-synthetic-platelets-to-stop-internal-bleeding-resulting-from-trauma/

Cardiovascular Disease (CVD) and the Role of agent alternatives in endothelial Nitric Oxide Synthase (eNOS) Activation and Nitric Oxide Production July 19, 2012

Curator and Research Study Originator: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/07/19/cardiovascular-disease-cvd-and-the-role-of-agent-alternatives-in-endothelial-nitric-oxide-synthase-enos-activation-and-nitric-oxide-production/

Macrovascular Disease – Therapeutic Potential of cEPCs: Reduction Methods for CV Risk

July 2, 2012

An Investigation of the Potential of circulating Endothelial Progenitor Cells (cEPCs) as a Therapeutic Target for Pharmacological Therapy Design for Cardiovascular Risk Reduction: A New Multimarker Biomarker Discovery

Curator: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2012/07/02/macrovascular-disease-therapeutic-potential-of-cepcs-reduction-methods-for-cv-risk/

Bone remodelling in a nutshell June 22, 2012

Author: Aviral Vatsa, Ph.D., MBBS

http://pharmaceuticalintelligence.com/2012/06/22/bone-remodelling-in-a-nutshell/

Targeted delivery of therapeutics to bone and connective tissues: current status and challenges- Part, September  

Author: Aviral Vatsa, PhD, September 23, 2012

http://pharmaceuticalintelligence.com/2012/09/23/targeted-delivery-of-therapeutics-to-bone-and-connective-tissues-current-status-and-challenges-part-i/

Calcium dependent NOS induction by sex hormones: Estrogen

Curator: S. Saha, PhD, October 3, 2012

http://pharmaceuticalintelligence.com/2012/10/03/calcium-dependent-nos-induction-by-sex-hormones/

Nitric Oxide and Platelet Aggregation,

Author V. Karra, PhD, August 16, 2012

http://pharmaceuticalintelligence.com/2012/08/16/no-and-platelet-aggregation/

Bystolic’s generic Nebivolol – positive effect on circulating Endothelial Progenitor Cells endogenous augmentation

Curator: Aviva Lev-Ari, PhD, July 16, 2012

http://pharmaceuticalintelligence.com/?s=Nebivolol

Endothelin Receptors in Cardiovascular Diseases: The Role of eNOS Stimulation

Author: Aviva Lev-Ari, PhD, 10/4/2012

http://pharmaceuticalintelligence.com/2012/10/04/endothelin-receptors-in-cardiovascular-diseases-the-role-of-enos-stimulation/

Inhibition of ET-1, ETA and ETA-ETB, Induction of NO production, stimulation of eNOS and Treatment Regime with PPAR-gamma agonists (TZD): cEPCs Endogenous Augmentation for Cardiovascular Risk Reduction – A Bibliography

Curator: Aviva Lev-Ari, 10/4/2012.

http://pharmaceuticalintelligence.com/2012/10/04/inhibition-of-et-1-eta-and-eta-etb-induction-of-no-production-and-stimulation-of-enos-and-treatment-regime-with-ppar-gamma-agonists-tzd-cepcs-endogenous-augmentation-for-cardiovascular-risk-reduc/

Nitric Oxide Nutritional remedies for hypertension and atherosclerosis. It’s 12 am: do you know where your electrons are?

Author and Reporter: Meg Baker, 10/7/2012.

http://pharmaceuticalintelligence.com/2012/10/07/no-nutritional-remedies-for-hypertension-and-atherosclerosis-its-12-am-do-you-know-where-your-electrons-are/

 

Read Full Post »

Author: Ritu Saxena, Ph.D.

Recently, two world renowned innovators, Steve Jobs-the CEO of Apple Inc. and Dr. Steinman-winner of 2011 Nobel prize in Physiology or medicine lost their life battle against Pancreatic cancer. Although both Jobs and Steinman suffered from the same disease, they were diagnosed with two fundamentally different forms of cancer of pancreas.

Steve lived with the disease for 8 years, a relatively long time for Pancreatic cancer patients to survive. The reason is attributed to the rare form of cancer of pancreas he suffered from-referred to as pancreatic neuroendocrine tumor. Steinman, on the other hand died due to a more common form of pancreatic cancer, the adenocarcenoma.

Neuroendocrine tumors arise from islands of hormone-producing cells (islets), that happen to be in that organ. Jobs learned in 2003 that he had an extremely rare form of this cancer, an islet-cell neuroendocrine tumor. In his email to  Apple employees in 2004, Steven Jobs wrote “I have some personal news that I need to share with you, and I wanted you to hear it directly from me,” Jobs said in the message, which he sent from his hospital bed. “I had a very rare form of pancreatic cancer called an islet cell neuroendocrine tumor, which represents about 1 percent of the total cases of pancreatic cancer diagnosed each year, and can be cured by surgical removal if diagnosed in time (mine was). I will not require any chemotherapy or radiation treatments.”

About 2,500 cases of pancreatic islet cell tumors are seen in the United States each year, according to the University of Southern California’s Center for Pancreatic and Biliary Diseases. These tumors, which are derived from neuroendocrine cells, tend to be slow growing and are treatable even after they have metastasized, said the center’s Web site.  http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2004/08/02/MNGMJ816F41.DTL&ao=all

The management strategy of neuroendrocrine tumors (NET) like any other disease is supposed to be curative where possible. As suggested by several researchers including Ramage et al (http://www.ncbi.nlm.nih.gov/pubmed/15686165, ), surgery is the only curative option currently available for NETs. The updated guidelines published for the NET management state the over the past few years, there have been advances in the management of neuroendocrine tumours, which have included clearer characterisation, more specific and therapeutically relevant diagnosis, and improved treatments. However, because of the uncommon nature of the disease, there remain few randomised trials in the field, hence all evidence mentioned in the research article is considered relatively weak compared with other more common cancers. For patients who are diagnosed early enough to be candidates for surgery, the aim is to keep the patient disease- and symptom-free for as long as possible. For patients suffering from advanced-stage NETs, operative therapy is rarely curative and chemotherapy could be used on metastasized NETs. http://www.ncbi.nlm.nih.gov/pubmed/22052063.

As reported in a story covered by CNN in 2008, there was a lot of speculation when he appeared rail-thin at the unveiling of the new iPhone. Jobs eventually said in January 2009 that doctors said he dropped so much weight because of “a hormone imbalance that has been ‘robbing’ me of the proteins my body needs to be healthy. Sophisticated blood tests have confirmed this diagnosis.” http://tech.fortune.cnn.com/2008/06/13/steve-jobs-life-after-the-whipple/ This statement explains how symptoms of hormonal excess in NET patients must be controlled before surgical procedure is followed. Also, recommended management of the symptoms of hormonal hypersecretion depends on the hormone secreted. For example, glucose levels in patients with insulinomas should be stabilized with diet and/or diazoxide. Gastrin hypersecretion in patients with gastrinomas may be managed with proton pump inhibitors (PPIs). http://www.neuroendocrinetumor.com/health-care-professional/net-treatment-options.jsp

Steinman, on the other hand, suffered from adenocarcenoma that arises from the pancreatic cells themselves, referred to as the “far more common form of pancreatic cancer” by Jobs. He further wrote in his memo “…(adenocarcenoma) is currently not curable and usually carries a life expectancy of around one year after diagnosis. I mention this because when one hears ‘pancreatic cancer’ (or Googles it), one immediately encounters this far more common and deadly form, which, thank God, is not what I had.”

Dr. Steinman won the 2011 Nobel Prize for Medicine or Physiology for his early-career landmark discovery about the immune system in the 1970s when he first described ‘dendritic cells’ with the help of his mentor Zanvil Cohn at Rockefeller University. Unfortunately, he died just three days before the official announcement. http://www.scientificamerican.com/article.cfm?id=steinman-nobel-laureate-explains-discovery-dendritic-cells. He had been suffering from pancreatic cancer for four years, had been undergoing treatment using a pioneering immunotherapy based on his own research. Dendritic cells from his body were deployed to mount an assault on his cancer. His early research at Rockefeller, began as an attempt to understand the primary white cells of the immune system — the large “eating” macrophages and the exquisitely specific lymphocytes, which operate in a variety of ways to spot, apprehend and destroy infectious microorganisms and tumor cells. Steinman’s subsequent research pointed to dendritic cells as important and unique accessories in the onset of several immune responses, including clinically important situations such as rejection of graft, resistance to tumors, autoimmune diseases and infections including AIDS. http://newswire.rockefeller.edu/2011/10/03/rockefeller-university-scientist-ralph-steinman-honored-today-with-nobel-prize-for-discovery-of-dendritic-cells-dies-at-68/

The standard of care in the United States for the treatment of locally advanced pancreatic cancer is a combination of low-dose chemotherapy given simultaneously with radiation treatments to the pancreas and surrounding tissues. Radiation treatments are designed to lower the risk of local growth of the cancer, thereby minimizing the symptoms that local progression causes (back or belly pain, nausea, loss of appetite, intestinal blockage, jaundice). http://www.medicinenet.com/pancreatic_cancer/page6.htm#advanced

Research Efforts on Pancreatic Cancer: The untimely passing of the geniuses reminds us how important research in the area of pancreatic cancer is which lead to finding new therapeutic targets that might stem reliable therapies. A recent example is the report published in Science Daily stating that the protein RGL2 might be a promising therapeutic target for pancreatic cancer. http://www.sciencedaily.com/releases/2010/11/101105101400.htm. The conclusion was derived via research published in November in the Journal of Biological Chemistry by a team led by Channing Der, PhD from UNC Lineberger Cancer Center. http://www.jbc.org/content/285/45/34729.long   For almost three decades, scientists and physicians have known that a gene called the KRAS oncogene is mutated in virtually all pancreatic cancers, making it an important target for scientists looking for a way to stop the growth of pancreatic cancer tumors. The problem is that the KRAS gene triggers cancer cell growth in numerous ways, through multiple cell signaling pathways, and scientists have had difficulty determining which one will be the most promising to block — an important first step in designing a drug for use in patients. Dr. Der said that “We are particularly optimistic about RGL2 because we know that this protein is a critical component of KRAS signaling to another class of proteins called Ral GTPases, which are essential for the growth of almost all pancreatic tumors.”

Another groundbreaking research was published in the journal Nature talks about discovering the link between a gene and the prognosis of Pancreatic Ductal Adenocarcenoma. The team found that when a gene involved in protein degradation is switched-off through chemical tags on the DNA’s surface, pancreatic cancer cells are protected from the bodies’ natural cell death processes, become more aggressive, and can rapidly spread. Their research study proposed USP9X to be a major tumour suppressor gene with prognostic and therapeutic relevance in pancreatic cancer. http://www.sanger.ac.uk/about/press/2012/120429.html http://www.nature.com/nature/journal/vaop/ncurrent/pdf/nature11114.pdf

Although, most of the research efforts are concentrated on the more common form of cancer, pancreatic adenocarcenoma, similar research efforts are needed for developing cure for the uncommon form, the one Steve Jobs suffered from, neuroendocrine cancer.

What we lost to the disease is more than the two geniuses, we lost the possibility of further innovation that might have changed the world in ways we could not imagine. The loss, though, sheds light on the importance of finding a cure for the disease and its different types. Hope the research community is able to interpret and find answers to the enigma of Pancreatic cancer and its diverse forms in which it strikes.

Read Full Post »

« Newer Posts