Subtitle: Nitric Oxide, Peroxinitrite, and NO donors in Renal Function Loss
Curator and Author: Larry H. Bernstein, MD, FCAP
The Nitric Oxide and Renal is presented in FOUR parts:
Part I: The Amazing Structure and Adaptive Functioning of the Kidneys: Nitric Oxide
Part II: Nitric Oxide and iNOS have Key Roles in Kidney Diseases
Part III: The Molecular Biology of Renal Disorders: Nitric Oxide
Part IV: New Insights on Nitric Oxide donors
Conclusion to this series is presented in
The Essential Role of Nitric Oxide and Therapeutic NO Donor Targets in Renal Pharmacotherapy
Part II. Oxidative Stress and Regulating a Balance of Redox Potential is Central to Disordered Kidney Function
We have already described the key role that nitric oxide and the NO synthases play in reduction of oxidative stress. The balance that has to be regulated between pro- and anti-oxidative as well as inflammatory elements necessary for renal function, critically involves the circulation of the kidney. It poses an inherent risk in the kidney, where the existence of a rich circulatory and high energy cortical outer region surrounds a medullary inner portion that is engaged in the retention of water, the active transport of glucose, urea and uric acid nitrogenous waste, mineral balance and pH. In this discussion we shall look at kidney function, NO, and the large energy fluxes in the medullary tubules and interstitium. This is a continuation of of a series of posts on NO and NO related disorders, and the kidney in particular.
Part IIa. Nitric Oxide role in renal tubular epithelial cell function
Tubulointerstitial Nephritides
As part of the exponential growth in our understanding of nitric oxide (NO) in health and disease over the past 2 decades, the kidney has become appreciated as a major site where NO may play a number of important roles. Although earlier work on the kidney focused more on effects of NO at the level of larger blood vessels and glomeruli, there has been a rapidly growing body of work showing critical roles for NO in tubulointerstitial disease. In this review we discuss some of the recent contributions to this important field.
Mattana J, Adamidis A, Singhal PC. Nitric oxide and tubulointerstitial nephritides. Seminars in Nephrology 2004; 24(4):345-353.
Nitric oxide donors and renal tubular (subepithelial) matrix
Nitric oxide (NO) and its metabolite, peroxynitrite (ONOO-), are involved in renal tubular cell injury. If NO/ONOO- has an effect to reduce cell adhesion to the basement membrane, does this effect contribute to tubular obstruction and would it be partially responsible for the harmful effect of NO on the tubular epithelium during acute renal failure (ARF)?
Wangsiripaisan A, et al. examined the effect of the NO donors
- (z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1- ium-1, 2-diolate (DETA/NO),
- spermine NONOate (SpNO), and
- the ONOO- donor 3-morpholinosydnonimine (SIN-1)
on cell-matrix adhesion to collagen types I and IV, and also fibronectin
using three renal tubular epithelial cell lines:
- LLC-PK1,
- BSC-1,
- OK.
It was only the exposure to SIN-1 that caused a dose-dependent impairment in cell-matrix adhesion. Similar results were obtained in the different cell types and matrix proteins. The effect of SIN-1 (500 microM) on LLC-PK1 cell adhesion was not associated with either cell death or alteration of matrix protein and was attenuated by either
- the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide,
- the superoxide scavenger superoxide dismutase, or
- the ONOO- scavenger uric acid in a dose-dependent manner.
These investigators concluded in this seminal paper that ONOO- generated in the tubular epithelium during ischemia/reperfusion has the potential to impair the adhesion properties of tubular cells, which then may contribute to the tubular obstruction in ARF.
Wangsiripaisan A, Gengaro PE, Nemenoff RA, Ling H, et al. Effect of nitric oxide donors on renal tubular epithelial cell-matrix adhesion. Kidney Int 1999; 55(6):2281-8.

English: Reactions leading to generation of Nitric Oxide and Reactive Nitrogen Species. Novo and Parola Fibrogenesis & Tissue Repair 2008 1:5 doi:10.1186/1755-1536-1-5 (Photo credit: Wikipedia)
Coexpressed Nitric Oxide Synthase and Apical β1 Integrins
In sepsis-induced acute renal failure, actin cytoskeletal alterations result in shedding of proximal tubule epithelial cells (PTEC) and tubular obstruction. This study examined the hypothesis that inflammatory cytokines, released early in sepsis, cause PTEC cytoskeletal damage and alter integrin-dependent cell-matrix adhesion. The question of whether the intermediate nitric oxide (NO) modulates these cytokine effects was also examined.
After exposure of human PTEC to
- tumor necrosis factor-α,
- interleukin-1α, and
- interferon-γ,
the actin cytoskeleton was disrupted and cells became elongated, with extension of long filopodial processes.
Cytokines induced shedding of
- viable,
- apoptotic, and
- necrotic PTEC,
which was dependent on NO synthesized by inducible NO synthase (iNOS) produced as a result of cytokine actions on PTEC.
Basolateral exposure of polarized PTEC monolayers to cytokines induced maximal NO-dependent cell shedding, mediated in part through NO effects on cGMP. Cell shedding was accompanied by dispersal of
- basolateral β1 integrins and
- E-cadherin,
with corresponding upregulation of integrin expression in clusters of cells elevated above the epithelial monolayer.
These cells demonstrated coexpression of iNOS and apically redistributed β1 integrins. These authors point out that the major ligand involved in cell anchorage was laminin, probably through interactions with the integrin α3β1. This interaction was downregulated by cytokines but was not dependent on NO. They posulate a mechanism by which inflammatory cytokines induce PTEC damage in sepsis, in the absence of hypotension and ischemia.
Glynne PA, Picot J and Evans TJ. Coexpressed Nitric Oxide Synthase and Apical β1 Integrins Influence Tubule Cell Adhesion after Cytokine-Induced Injury. JASN 2001; 12(11): 2370-2383.
Potentiation by Nitric Oxide of Apoptosis in Renal Proximal Tubule Cells
Proximal tubular epithelial cells (PTEC) exhibit a high sensitivity to undergo apoptosis in response to proinflammatory stimuli and immunosuppressors and participate in the onset of several renal diseases. This study examined the expression of inducible nitric oxide (NO) synthase after challenge of PTEC with bacterial cell wall molecules and inflammatory cytokines and analyzed the pathways that lead to apoptosis in these cells by measuring changes in the mitochondrial transmembrane potential and caspase activation.
The data show that the apoptotic effects of proinflammatory stimuli mainly were due to the expression of inducible NO synthase. Cyclosporin A and FK506 inhibited partially NO synthesis. However, both NO and immunosuppressors induced apoptosis, probably through a common mechanism that involved the irreversible opening of the mitochondrial permeability transition pore. Activation of caspases 3 and 7 was observed in cells treated with high doses of NO and with moderate concentrations of immunosuppressors. The conclusion is that the cooperation between NO and immunosuppressors that induce apoptosis in PTEC might contribute to the renal toxicity observed in the course of immunosuppressive therapy.
HORTELANO S, CASTILLA M, TORRES AM, TEJEDOR A, and BOSCÁ L. Potentiation by Nitric Oxide of Cyclosporin A and FK506- Induced Apoptosis in Renal Proximal Tubule Cells. J Am Soc Nephrol 2000; 11: 2315–2323.
Part IIb. Related studies with ROS and/or RNS on nonrenal epithelial cells
Reactive nitrogen species block cell cycle re-entry
Endogenous sources of reactive nitrogen species (RNS) act as second messengers in a variety of cell signaling events, whereas environmental sources of RNS like nitrogen dioxide (NO2) inhibit cell survival and growth through covalent modification of cellular macromolecules.
Murine type II alveolar cells arrested in G0 by serum deprivation were exposed to either NO2 or SIN-1, a generator of RNS, during cell cycle re-entry. In serum-stimulated cells, RNS blocked cyclin D1 gene expression, resulting in cell cycle arrest at the boundary between G0 and G1. Dichlorofluorescin diacetate (DCF) fluorescence indicated that RNS induced sustained production of intracellular hydrogen peroxide (H2O2), which normally is produced only transiently in response to serum growth factors.
Loading cells with catalase prevented enhanced DCF fluorescence and rescued cyclin D1 expression and S phase entry.
These studies indicate environmental RNS interfere with cell cycle re-entry through an H2O2-dependent mechanism that influences expression of cyclin D1 and progression from G0 to the G1 phase of the cell cycle.
Yuan Z, Schellekens H, Warner L, Janssen-Heininger Y, Burch P, Heintz NH. Reactive nitrogen species block cell cycle re-entry through sustained production of hydrogen peroxide. Am J Respir Cell Mol Biol. 2003;28(6):705-12. Epub 2003 Jan 10.
Peroxynitrite modulates MnSOD gene expression
Peroxynitrite (ONOO-) is a strong oxidant derived from nitric oxide (‘NO) and superoxide (O2.-), reactive nitrogen (RNS) and oxygen species (ROS) present in inflamed tissue. Other oxidant stresses, e.g., TNF-alpha and hyperoxia, induce mitochondrial, manganese-containing superoxide dismutase (MnSOD) gene expression.
3-morpholinosydnonimine HCI (SIN-1) (10 or 1000 microM) increased MnSOD mRNA, but did not change hypoxanthine guanine phosphoribosyl transferase (HPRT) mRNA.
Authentic peroxynitrite (ONOO ) (100-500 microM) also increased MnSOD mRNA but did not change constitutive HPRT mRNA expression. ONOO stimulated luciferase gene expression driven by a 2.5 kb fragment of the rat MnSOD gene 5′ promoter region.
MnSOD gene induction due to ONOO- was inhibited effectively by L-cysteine (10 mM) and partially inhibited by N-acetyl cysteine (50 mM) or pyrrole dithiocarbamate (10 mM).
.NO from 1-propanamine, 3-(2-hydroxy-2-nitroso-1-propylhydrazine) (PAPA NONOate) (100 or 1000 microM) did not change MnSOD or HPRT mRNA, nor did either H202 or NO2-, breakdown products of SIN-1 and ONOO, have any effect on MnSOD mRNA expression; ONOO- and SIN-1 also did not increase detectable MnSOD protein content or increase MnSOD enzymatic activity.
Nevertheless, increased steady state [O2.-] in the presence of .NO yields ONOO , and ONOO has direct, stimulatory effects on MnSOD transcript expression driven at the MnSOD gene 5′ promoter region inhibited completely by L-cysteine and partly by N-acetyl cysteine in lung epithelial cells. This raises a question of whether the same effect is seen in renal tubular epithelium.
Jackson RM, Parish G, Helton ES. Peroxynitrite modulates MnSOD gene expression in lung epithelial cells. Free Radic Biol Med. 1998; 25(4-5):463-72.
Comparative impacts of glutathione peroxidase-1 gene knockout on oxidative stress
Selenium-dependent glutathione peroxidase-1 (GPX1) protects against reactive-oxygen-species (ROS)-induced oxidative stress in vivo, but its role in coping with reactive nitrogen species (RNS) is unclear. Primary hepatocytes were isolated from GPX1-knockout (KO) and wild-type (WT) mice to test protection of GPX1 against cytotoxicity of
- superoxide generator diquat (DQ),
- NO donor S-nitroso-N-acetyl-penicillamine (SNAP) and
- peroxynitrite generator 3-morpholinosydnonimine (SIN-1).
Treating cells with SNAP (0.1 or 0.25 mM) in addition to DQ produced synergistic cytotoxicity that minimized differences in apoptotic cell death and oxidative injuries between the KO and WT cells. Less protein nitrotyrosine was induced by 0.05-0.5 mM DQ+0.25 mM SNAP in the KO than in the WT cells.
Total GPX activity in the WT cells was reduced by 65 and 25% by 0.5 mM DQ+0.1 mM SNAP and 0.5 mM DQ, respectively.
Decreases in Cu,Zn-superoxide dismutase (SOD) activity and increases in Mn-SOD activity in response to DQ or DQ+SNAP were greater in the KO cells than in the WT cells.
The study indicates GPX1 was more effective in protecting hepatocytes against oxidative injuries mediated by ROS alone than by ROS and RNS together, and knockout of GPX1 did not enhance cell susceptibility to RNS-associated cytotoxicity. Instead, it attenuated protein nitration induced by DQ+SNAP.
To better understand the mechanism(s) underlying nitric oxide (. NO)-mediated toxicity, in the presence and absence of concomitant oxidant exposure, postmitotic terminally differentiated NT2N cells, which are incapable of producing . NO, were exposed to PAPA-NONOate (PAPA/NO) and 3-morpholinosydnonimine (SIN-1).
Exposure to SIN-1, which generated peroxynitrite (ONOO) in the range of 25-750 nM/min, produced a concentration- and time-dependent delayed cell death.
In contrast, a critical threshold concentration (>440 nM/min) was required for . NO to produce significant cell injury.
There is a largely necrotic lesion after ONOO exposure and an apoptotic-like morphology after . NO exposure. Cellular levels of reduced thiols correlated with cell death, and pretreatment with N-acetylcysteine (NAC) fully protected from cell death in either PAPA/NO or SIN-1 exposure.
NAC given within the first 3 h posttreatment further delayed cell death and increased the intracellular thiol level in SIN-1 but not . NO-exposed cells.
Cell injury from . NO was independent of cGMP, caspases, and superoxide or peroxynitrite formation.
Overall, exposure of non-. NO-producing cells to . NO or peroxynitrite results in delayed cell death, which, although occurring by different mechanisms,
appears to be mediated by the loss of intracellular redox balance.
Gow AJ, Chen Q, Gole M, Themistocleous M, Lee VM, Ischiropoulos H. Two distinct mechanisms of nitric oxide-mediated neuronal cell death show thiol dependency. Am J Physiol Cell Physiol. 2000; 278(6):C1099-107.

English: Binding of CAPON results in a reduction of NMDA receptor/nitric oxide synthase (NOS) complexes, leading to decreased NMDA receptor–gated calcium influx and a catalytically inactive nitric oxide synthase. Overexpression of either the full-length or the novel shortened CAPON isoform as reported by Brzustowicz and colleagues is, therefore, predicted to lead to impaired NMDA receptor–mediated glutamate neurotransmission. (Photo credit: Wikipedia)
NO2 effect on phosphatidyl choline
Nitrogen dioxide (NO2) inhalation affects the extracellular surfactant as well as the structure and function of type II pneumocytes. The studies had differences in oxidant concentration, duration of exposure, and mode of NO2 application.
This study evaluated the influence of the NO2 application mode on the phospholipid metabolism of type II pneumocytes . Rats were exposed to identical NO2 body doses (720 ppm x h), which were applied continuously (10 ppm for 3 d), intermittently (10 ppm for 8 h per day, for 9 d), and repeatedly (10 ppm for 3 d, 28 d rest, and then 10 ppm for 3 d). Immediately after exposure, type II cells were isolated and evaluated for
- cell yield,
- vitality,
- phosphatidylcholine (PC) synthesis, and
- secretion.
Type II pneumocyte cell yield was only increased from animals that had been continuously exposed to NO2, but vitality of the isolated type II pneumocytes was not affected by the NO2 exposure modes. Continuous application of 720 ppm x h NO2 resulted in increased activity of the cytidine-5-diphosphate (CDP)-choline pathway.
- After continuous NO2 application,
- specific activity of choline kinase,
- cytidine triphosphate (CTP):cholinephosphate cytidylyltransferase,
- uptake of choline, and
- pool sizes of CDP-choline and PC
were significantly increased over those of controls.
Intermittent application of this NO2 body dose provoked less increase in PC synthesis and the synthesis parameters were comparable to those for cells from control animals after repeated exposure. Whereas PC synthesis in type II cells was stimulated by NO2, their secretory activity was reduced. Continuous exposure reduced the secretory activity most, whereas intermittent exposure nonsignificantly reduced this activity as compared with that of controls. The repeated application of NO2 produced no differences.
The authors conclude that type II pneumocytes adapt to NO2 atmospheres depending on the mode of its application, at least for the metabolism of PC and its secretion from isolated type II pneumocytes. Further studies are necessary to determine whether additional metabolic activities will also adapt to NO2 atmospheres, and if these observations are specific for NO2 or represent effects generally due to oxidants. The reader, however, asks whether this effect could also be found in renal epithelial cells, for which PC is not considered vital as for type II pneumocytes and possibly related to surfactant activity in the lung.
Müller B, Seifart C, von Wichert P, Barth PJ. Adaptation of rat type II pneumocytes to NO2: effects of NO2 application mode on phosphatidylcholine metabolism. Am J Respir Cell Mol Biol. 1998; 18(5): 712-20.
iNOS involved in immediate response to anaphylaxis
The generation of large quantities of nitric oxide (NO) is implicated in the pathogenesis of anaphylactic shock. The source of NO, however, has not been established and conflicting results have been obtained when investigators have tried to inhibit its production in anaphylaxis.
This study analyzed the expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) in a mouse model of anaphylaxis.
BALB/c mice were sensitized and challenged with ovalbumin to induce anaphylaxis. Tissues were removed from the heart and lungs, and blood was drawn at different time points during the first 48 hours after induction of anaphylaxis. The Griess assay was used to measure nitric oxide generation. Nitric oxide synthase expression was examined by reverse transcriptase polymerase chain reaction and immunohistochemistry.
A significant increase in iNOS mRNA expression and nitric oxide production was evident as early as 10 to 30 minutes after allergen challenge in both heart and lungs. In contrast, expression of eNOS mRNA was not altered during the course of the experiment.
The results support involvement of iNOS in the immediate physiological response of anaphylaxis.
Sade K, Schwartz IF, Etkin S, Schwartzenberg S, et al. Expression of Inducible Nitric Oxide
Synthase in a Mouse Model of Anaphylaxis. J Investig Allergol Clin Immunol 2007; 17(6):379-385.
Part IIc. Additional Nonrenal Related NO References
Nitrogen dioxide induces death in lung epithelial cells in a density-dependent manner.
Persinger RL, Blay WM, Heintz NH, Hemenway DR, Janssen-Heininger YM.
Am J Respir Cell Mol Biol. 2001 May;24(5):583-90.
PMID: 11350828 [PubMed – indexed for MEDLINE] Free Article
2.
Molecular mechanisms of nitrogen dioxide induced epithelial injury in the lung.
Persinger RL, Poynter ME, Ckless K, Janssen-Heininger YM.
Mol Cell Biochem. 2002 May-Jun;234-235(1-2):71-80. Review.
PMID: 12162462 [PubMed – indexed for MEDLINE]
3.
Nitric oxide and peroxynitrite-mediated pulmonary cell death.
Gow AJ, Thom SR, Ischiropoulos H.
Am J Physiol. 1998 Jan;274(1 Pt 1):L112-8.
PMID: 9458808 [PubMed – indexed for MEDLINE] Free Article
4.
Mitogen-activated protein kinases mediate peroxynitrite-induced cell death in human bronchial epithelial cells.
Nabeyrat E, Jones GE, Fenwick PS, Barnes PJ, Donnelly LE.
Am J Physiol Lung Cell Mol Physiol. 2003 Jun;284(6):L1112-20. Epub 2003 Feb 21.
PMID: 12598225 [PubMed – indexed for MEDLINE] Free Article
5.
Peroxynitrite inhibits inducible (type 2) nitric oxide synthase in murine lung epithelial cells in vitro.
Robinson VK, Sato E, Nelson DK, Camhi SL, Robbins RA, Hoyt JC.
Free Radic Biol Med. 2001 May 1;30(9):986-91.
PMID: 11316578 [PubMed – indexed for MEDLINE]
6.
Nitric oxide-mediated chondrocyte cell death requires the generation of additional reactive oxygen species.
Del Carlo M Jr, Loeser RF.
Arthritis Rheum. 2002 Feb;46(2):394-403.
PMID: 11840442 [PubMed – indexed for MEDLINE]
7.
Colon epithelial cell death in 2,4,6-trinitrobenzenesulfonic acid-induced colitis is associated with increased inducible nitric-oxide synthase expression and peroxynitrite production.
Yue G, Lai PS, Yin K, Sun FF, Nagele RG, Liu X, Linask KK, Wang C, Lin KT, Wong PY.
J Pharmacol Exp Ther. 2001 Jun;297(3):915-25.
PMID: 11356911 [PubMed – indexed for MEDLINE] Free Article
Summary
In this piece I have covered the conflicting roles of endogenous end inducible nitric oxide (eNOS and iNOS) in the reaction to reactive oxygen and nitrogen stress (ROS, RNS), and many experiments directed at sorting out these effects using continuous and intermittent delivery of NO2, production of ONOO- from .NO, and several agents that are used to upregulate and downregulate the underlying mechanism of response. These investigations are not only carried out in experiments on renal function and apoptosis, but also there are similar examples taken from studies of lung and liver. This forms a backdrop for the assessment of renal diseases:
- immune related
- acute traumatic injury
- chronic
The continuation of the discussion will be in essays that follow.
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