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Archive for the ‘Proteomics’ Category


Predicting the Protein Structure of Coronavirus: Inhibition of Nsp15 can slow viral replication and Cryo-EM – Spike protein structure (experimentally verified) vs AI-predicted protein structures (not experimentally verified) of DeepMind (Parent: Google) aka AlphaFold

 

Curators: Stephen J. Williams, PhD and Aviva Lev-Ari, PhD, RN

This illustration, created at the Centers for Disease Control and Prevention (CDC), reveals ultrastructural morphology exhibited by coronaviruses. Note the spikes that adorn the outer surface of the virus, which impart the look of a corona surrounding the virion, when viewed electron microscopically. A novel coronavirus virus was identified as the cause of an outbreak of respiratory illness first detected in Wuhan, China in 2019.

Image and Caption Credit: Alissa Eckert, MS; Dan Higgins, MAM available at https://phil.cdc.gov/Details.aspx?pid=23311

 

UPDATED on 3/11/2020

Coronaviruses

According to the World Health Organization, coronaviruses make up a large family of viruses named for the crown-like spikes found on their surface (Figure 1). They carry their genetic material in single strands of RNA and cause respiratory problems and fever. Like HIV, coronaviruses can be transmitted between animals and humans.  Coronaviruses have been responsible for the Severe Acute Respiratory Syndrome (SARS) pandemic in the early 2000s and the Middle East Respiratory Syndrome (MERS) outbreak in South Korea in 2015. While the most recent coronavirus, COVID-19, has caused international concern, accessible and inexpensive sequencing is helping us understand COVID-19 and respond to the outbreak quickly.

Figure 1. Coronaviruses with the characteristic spikes as seen under a microscope.

First studies that explore genetic susceptibility to COVID-19 are now being published. The first results indicate that COVID-19 infects cells using the ACE2 cell-surface receptor. Genetic variants in the ACE2 receptor gene are thus likely to influence how effectively COVID-19 can enter the cells in our bodies. Researchers hope to discover genetic variants that confer resistance to a COVID-19 infection, similar to how some variants in the CCR5 receptor gene make people immune to HIV. At Nebula Genomics, we are monitoring the latest COVID-19 research and will add any relevant discoveries to the Nebula Research Library in a timely manner.

The Role of Genomics in Responding to COVID-19

Scientists in China sequenced COVID-19’s genome just a few weeks after the first case was reported in Wuhan. This stands in contrast to SARS, which was discovered in late 2002 but was not sequenced until April of 2003. It is through inexpensive genome-sequencing that many scientists across the globe are learning and sharing information about COVID-19, allowing us to track the evolution of COVID-19 in real-time. Ultimately, sequencing can help remove the fear of the unknown and allow scientists and health professionals to prepare to combat the spread of COVID-19.

Next-generation DNA sequencing technology has enabled us to understand COVID-19 is ~30,000 bases long. Moreover, researchers in China determined that COVID-19 is also almost identical to a coronavirus found in bats and is very similar to SARS. These insights have been critical in aiding in the development of diagnostics and vaccines. For example, the Centers for Disease Control and Prevention developed a diagnostic test to detect COVID-19 RNA from nose or mouth swabs.

Moreover, a number of different government agencies and pharmaceutical companies are in the process of developing COVID-19 vaccines to stop the COVID-19 from infecting more people. To protect humans from infection inactivated virus particles or parts of the virus (e.g. viral proteins) can be injected into humans. The immune system will recognize the inactivated virus as foreign, priming the body to build immunity against possible future infection. Of note, Moderna Inc., the National Institute of Allergy and Infectious Diseases, and Coalition for Epidemic Preparedness Innovations identified a COVID-19 vaccine candidate in a record 42 days. This vaccine will be tested in human clinical trials starting in April.

For more information about COVID-19, please refer to the World Health Organization website.

SOURCE

https://blog.nebula.org/role-of-genomics-coronavirus-covid-19/?utm_source=Nebula%20Genomics&utm_medium=email&utm_campaign=COVID-19

Aviva Lev-Ari
13.3K Tweets

Aviva Lev-Ari
@AVIVA1950

My BIO lnkd.in/eEyn69r MediaPharma ex-SRI ex-MITRE ex-McGraw-Hill Followed by

Aviva Lev-Ari
@AVIVA1950

Predicting the #ProteinStructure of #Coronavirus: #Inhibition of #Nsp15 #Cryo-EM – #spike #protein structure (#experimentally verified) vs #AI-predicted protein structures (not verified) of

(

) #AlphaFold

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Eric Topol
@EricTopol
·
The problem w/ visionaries is that we don’t recognize them in a timely manner (too late) Ralph Baric @UNCpublichealth and Vineet Menachery deserve recognition for being 5 yrs ahead of #COVID19 nature.com/articles/nm.39 @NatureMedicine pnas.org/content/113/11 @PNASNews via @hoondy

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Senior, A.W., Evans, R., Jumper, J. et al. Improved protein structure prediction using potentials from deep learningNature 577, 706–710 (2020)https://doi.org/10.1038/s41586-019-1923-7

Abstract

Protein structure prediction can be used to determine the three-dimensional shape of a protein from its amino acid sequence1. This problem is of fundamental importance as the structure of a protein largely determines its function2; however, protein structures can be difficult to determine experimentally. Considerable progress has recently been made by leveraging genetic information. It is possible to infer which amino acid residues are in contact by analysing covariation in homologous sequences, which aids in the prediction of protein structures3. Here we show that we can train a neural network to make accurate predictions of the distances between pairs of residues, which convey more information about the structure than contact predictions. Using this information, we construct a potential of mean force4 that can accurately describe the shape of a protein. We find that the resulting potential can be optimized by a simple gradient descent algorithm to generate structures without complex sampling procedures. The resulting system, named AlphaFold, achieves high accuracy, even for sequences with fewer homologous sequences. In the recent Critical Assessment of Protein Structure Prediction5 (CASP13)—a blind assessment of the state of the field—AlphaFold created high-accuracy structures (with template modelling (TM) scores6 of 0.7 or higher) for 24 out of 43 free modelling domains, whereas the next best method, which used sampling and contact information, achieved such accuracy for only 14 out of 43 domains. AlphaFold represents a considerable advance in protein-structure prediction. We expect this increased accuracy to enable insights into the function and malfunction of proteins, especially in cases for which no structures for homologous proteins have been experimentally determined7. https://doi.org/10.1038/s41586-019-1923-7

[ALA added bold face]

COVID-19 outbreak

The scientific community has galvanised in response to the recent COVID-19 outbreak, building on decades of basic research characterising this virus family. Labs at the forefront of the outbreak response shared genomes of the virus in open access databases, which enabled researchers to rapidly develop tests for this novel pathogen. Other labs have shared experimentally-determined and computationally-predicted structures of some of the viral proteins, and still others have shared epidemiological data. We hope to contribute to the scientific effort using the latest version of our AlphaFold system by releasing structure predictions of several under-studied proteins associated with SARS-CoV-2, the virus that causes COVID-19. We emphasise that these structure predictions have not been experimentally verified, but hope they may contribute to the scientific community’s interrogation of how the virus functions, and serve as a hypothesis generation platform for future experimental work in developing therapeutics. We’re indebted to the work of many other labs: this work wouldn’t be possible without the efforts of researchers across the globe who have responded to the COVID-19 outbreak with incredible agility.

Knowing a protein’s structure provides an important resource for understanding how it functions, but experiments to determine the structure can take months or longer, and some prove to be intractable. For this reason, researchers have been developing computational methods to predict protein structure from the amino acid sequence.  In cases where the structure of a similar protein has already been experimentally determined, algorithms based on “template modelling” are able to provide accurate predictions of the protein structure. AlphaFold, our recently published deep learning system, focuses on predicting protein structure accurately when no structures of similar proteins are available, called “free modelling”.  We’ve continued to improve these methods since that publication and want to provide the most useful predictions, so we’re sharing predicted structures for some of the proteins in SARS-CoV-2 generated using our newly-developed methods.

It’s important to note that our structure prediction system is still in development and we can’t be certain of the accuracy of the structures we are providing, although we are confident that the system is more accurate than our earlier CASP13 system. We confirmed that our system provided an accurate prediction for the experimentally determined SARS-CoV-2 spike protein structure shared in the Protein Data Bank, and this gave us confidence that our model predictions on other proteins may be useful. We recently shared our results with several colleagues at the Francis Crick Institute in the UK, including structural biologists and virologists, who encouraged us to release our structures to the general scientific community now. Our models include per-residue confidence scores to help indicate which parts of the structure are more likely to be correct. We have only provided predictions for proteins which lack suitable templates or are otherwise difficult for template modeling.  While these understudied proteins are not the main focus of current therapeutic efforts, they may add to researchers’ understanding of SARS-CoV-2.

Normally we’d wait to publish this work until it had been peer-reviewed for an academic journal. However, given the potential seriousness and time-sensitivity of the situation, we’re releasing the predicted structures as we have them now, under an open license so that anyone can make use of them.

Interested researchers can download the structures here, and can read more technical details about these predictions in a document included with the data. The protein structure predictions we’re releasing are for SARS-CoV-2 membrane protein, protein 3a, Nsp2, Nsp4, Nsp6, and Papain-like proteinase (C terminal domain). To emphasise, these are predicted structures which have not been experimentally verified. Work on the system continues for us, and we hope to share more about it in due course.

Citation:  John Jumper, Kathryn Tunyasuvunakool, Pushmeet Kohli, Demis Hassabis, and the AlphaFold Team, “Computational predictions of protein structures associated with COVID-19”, DeepMind website, 5 March 2020, https://deepmind.com/research/open-source/computational-predictions-of-protein-structures-associated-with-COVID-19

SARS-COV-2 MEMBRANE PROTEIN: A RENDERING OF ONE OF OUR PROTEIN STRUCTURE PREDICTIONS

SOURCES

Computational predictions of protein structures associated with COVID-19

https://deepmind.com/research/open-source/computational-predictions-of-protein-structures-associated-with-COVID-19

AlphaFold: Using AI for scientific discovery 

https://deepmind.com/blog/article/AlphaFold-Using-AI-for-scientific-discovery

 

DeepMind has shared its results with researchers at the Francis Crick Institute, a biomedical research lab in the UK, as well as offering it for download from its website.

“Normally we’d wait to publish this work until it had been peer-reviewed for an academic journal. However, given the potential seriousness and time-sensitivity of the situation, we’re releasing the predicted structures as we have them now, under an open license so that anyone can make use of them,” it said. [ALA added bold face]

There are 93,090 cases of COVID-19, and 3,198 deaths, spread across 76 countries, according to the latest report from the World Health Organization at time of writing. ®

SOURCE

https://www.theregister.co.uk/2020/03/06/deepmind_covid19_outbreak/

 

  • MHC content – The spike protein is thought to be the key to binding to cells via the angiotensin II receptor, the major mechanism the immune system uses to distinguish self from non-self

Preliminary Identification of Potential Vaccine Targets for the COVID-19 Coronavirus (SARS-CoV-2) Based on SARS-CoV Immunological Studies

Syed Faraz Ahmed 1,† , Ahmed A. Quadeer 1, *,† and Matthew R. McKay 1,2, *

1 Department of Electronic and Computer Engineering, The Hong Kong University of Science and

Technology, Hong Kong, China; sfahmed@connect.ust.hk

2 Department of Chemical and Biological Engineering, The Hong Kong University of Science and

Technology, Hong Kong, China

* Correspondence: eeaaquadeer@ust.hk.com (A.A.Q.); m.mckay@ust.hk (M.R.M.)

These authors contributed equally to this work.

Received: 9 February 2020; Accepted: 24 February 2020; Published: 25 February 2020

Abstract:

The beginning of 2020 has seen the emergence of COVID-19 outbreak caused by a novel coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). There is an imminent need to better understand this new virus and to develop ways to control its spread. In this study, we sought to gain insights for vaccine design against SARS-CoV-2 by considering the high genetic similarity between SARS-CoV-2 and SARS-CoV, which caused the outbreak in 2003, and leveraging existing immunological studies of SARS-CoV. By screening the experimentally determined SARS-CoV-derived B cell and T cell epitopes in the immunogenic structural proteins of SARS-CoV, we identified a set of B cell and T cell epitopes derived from the spike (S) and nucleocapsid (N) proteins that map identically to SARS-CoV-2 proteins. As no mutation has been observed in these identified epitopes among the 120 available SARS-CoV-2 sequences (as of 21 February 2020), immune targeting of these epitopes may potentially offer protection against this novel virus. For the T cell epitopes, we performed a population coverage analysis of the associated MHC alleles and proposed a set of epitopes that is estimated to provide broad coverage globally, as well as in China. Our findings provide a screened set of epitopes that can help guide experimental efforts towards the development of vaccines against SARS-CoV-2.

Keywords: Coronavirus; 2019-nCoV; 2019 novel coronavirus; SARS-CoV-2; COVID-19; SARS-CoV; MERS-CoV; T cell epitopes; B cell epitopes; vaccine [ALA added bold face]

SOURCE

https://www.mdpi.com/1999-4915/12/3/254/pdf

 

Selected Online COMMENTS to

https://forums.theregister.co.uk/forum/all/2020/03/06/deepmind_covid19_outbreak/

MuscleguySilver badge

Re: Protein structure prediction has been done for ages…

Not quite, Natural Selection does not measure methods, it measures outputs, usually at the organism level.

Sure correct folding is necessary for much protein function and we have prions and chaperone proteins to get it wrong and right.

The only way NS measures methods and mechanisms is if they are very energetically wasteful. But there are some very wasteful ones out there. Beta-Catenin at the end of point of Wnt signalling comes particularly to mind.

Chemist

Re: Does not matter at all

“Determining the structure of the virus proteins might also help in developing a molecule that disrupts the operation of just those proteins, and not anything else in the human body.”

Well it might, but predicting whether a ‘drug’ will NOT interact with any other of the 20000+ protein in complex organisms is well beyond current science. If we could do that we could predict/avoid toxicity and other non-mechanism related side-effects & mostly we can’t.

rob miller

Title

There are 480 structures on PDBe resulting from a search on ‘coronavirus,’ the top hits from MERS and SARS. PR stunt or not, they did win the most recent CASP ‘competition’, so arguably it’s probably our best shot right now – and I am certainly not satisfied that they have been sufficiently open in explaining their algorithms though I have not checked in the last few months. No one is betting anyone’s health on this, and it is not like making one wrong turn in a series of car directions. Latest prediction algorithms incorporate contact map predictions, so it’s not like a wrong dihedral angle sends the chain off in the wrong direction. A decent model would give something to run docking algorithms against with a series of already approved drugs, then we take that shortlist into the lab. A confirmed hit could be an instantly available treatment, no two year wait as currently estimated. [ALA added bold face]

jelabarre59Silver badge

Re: these structure predictions have not been experimentally verified

Naaaah. Can’t possibly be a stupid marketing stunt.

Well yes, a good possibility. But it can also be trying to build on the open-source model of putting it out there for others to build and improve upon. Essentially opening that “peer review” to a larger audience quicker. [ALA added bold face]

We shall see.

Anonymous Coward

Anonymous CowardWhat bothers me, besides the obvious PR stunt, is that they say this prediction is licensed. How can a prediction from software be protected by, I presume, patents? And if this can be protected without even verifying which predictions actually work, what’s to stop someone spitting out millions of random, untested predictions just in case they can claim ownership later when one of them is proven to work? [ALA added bold face]

 

 

SOURCES

 

  • AI-predicted protein structures could unlock vaccine for Wuhan coronavirus… if correct… after clinical trials It’s not quite DeepMind’s ‘Come with me if you want to live’ moment, but it’s close, maybe

Experimentally derived by a group of scientists at the University of Texas at Austin and the National Institute of Allergy and Infectious Diseases, an agency under the US National Institute of Health. They both feature a “Spike protein structure.”

  • Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation

See all authors and affiliations

Science  19 Feb 2020:
eabb2507
DOI: 10.1126/science.abb2507

 

  • Israeli scientists: We have developed a coronavirus vaccine

https://www.fromthegrapevine.com/health/coronavirus-vaccine-israel-migal-research-institute-david-zigdon

Other related articles published in this Open Access Online Scientific Journal include the following:

 

  • Group of Researchers @ University of California, Riverside, the University of Chicago, the U.S. Department of Energy’s Argonne National Laboratory, and Northwestern University solve COVID-19 Structure and Map Potential Therapeutics

Reporters: Stephen J Williams, PhD and Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2020/03/06/group-of-researchers-solve-covid-19-structure-and-map-potential-therapeutic/

 

  • Is It Time for the Virtual Scientific Conference?: Coronavirus, Travel Restrictions, Conferences Cancelled Curator:

Stephen J. Williams, PhD

https://pharmaceuticalintelligence.com/2020/03/06/is-it-time-for-the-virtual-scientific-conference-coronavirus-travel-restrictions-conferences-cancelled/

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Healing Powers of Fibrinogen

Reporter: Irina Robu, PhD

Recent research from University of Alberta is looking at the role of fibrinogen, the substrate of thrombin in regulating a natural defense mechanism in the body. Fibrinogen is a well-known protein that is essential for wound healing and blood clotting in the body. Levels of fibrinogen increase in inflammatory states as part of the acute-phase response.

However, daily variation in plasma fibrinogen levels weakens its potential as a biomarker of cardiovascular risk. The discovery is expected to contribute to enhanced diagnosis and treatments for patients in a variety of diseases ranging from inflammation, to heart failure, to cancer.

Yet, a study published in Scientific Reports in March 2019 show that fibrinogen can also be a natural inhibitor of an enzyme named MMP2, which is important for normal organ development and repair. The researchers believe an essential function of fibrinogen is to allow or disallow the enzyme to carry out its normal functions. Nevertheless, high levels of fibrinogen may disproportionately inhibit MMP2, that could result in arthritic and cardiac disorders.

The researcher highlights the inner workings of the MMP family of enzymes by having a greater understanding of how MMPs are regulated. They hypothesize that abnormal MMP2 activity could be an unwelcome side effect of common medications such as the cholesterol-lowering drugs and the antibiotic doxycycline, both of which are known to inhibit MMPs. They also emphasize that future therapeutic developments must strike a balance between the levels of MMPs and their inhibitors, such as fibrinogen, so that net MMP activity in the body remains at nearly normal levels.

SOURCE

https://www.technologynetworks.com/biopharma/news/healing-protein-also-hinders-320533?utm_campaign=NEWSLETTER_TN_Breaking%20Science%20News

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The Journey of Antibiotic Discovery

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

The term ‘antibiotic’ was introduced by Selman Waksman as any small molecule, produced by a microbe, with antagonistic properties on the growth of other microbes. An antibiotic interferes with bacterial survival via a specific mode of action but more importantly, at therapeutic concentrations, it is sufficiently potent to be effective against infection and simultaneously presents minimal toxicity. Infectious diseases have been a challenge throughout the ages. From 1347 to 1350, approximately one-third of Europe’s population perished to Bubonic plague. Advances in sanitary and hygienic conditions sufficed to control further plague outbreaks. However, these persisted as a recurrent public health issue. Likewise, infectious diseases in general remained the leading cause of death up to the early 1900s. The mortality rate shrunk after the commercialization of antibiotics, which given their impact on the fate of mankind, were regarded as a ‘medical miracle’. Moreover, the non-therapeutic application of antibiotics has also greatly affected humanity, for instance those used as livestock growth promoters to increase food production after World War II.

 

Currently, more than 2 million North Americans acquire infections associated with antibiotic resistance every year, resulting in 23,000 deaths. In Europe, nearly 700 thousand cases of antibiotic-resistant infections directly develop into over 33,000 deaths yearly, with an estimated cost over €1.5 billion. Despite a 36% increase in human use of antibiotics from 2000 to 2010, approximately 20% of deaths worldwide are related to infectious diseases today. Future perspectives are no brighter, for instance, a government commissioned study in the United Kingdom estimated 10 million deaths per year from antibiotic resistant infections by 2050.

 

The increase in antibiotic-resistant bacteria, alongside the alarmingly low rate of newly approved antibiotics for clinical usage, we are on the verge of not having effective treatments for many common infectious diseases. Historically, antibiotic discovery has been crucial in outpacing resistance and success is closely related to systematic procedures – platforms – that have catalyzed the antibiotic golden age, namely the Waksman platform, followed by the platforms of semi-synthesis and fully synthetic antibiotics. Said platforms resulted in the major antibiotic classes: aminoglycosides, amphenicols, ansamycins, beta-lactams, lipopeptides, diaminopyrimidines, fosfomycins, imidazoles, macrolides, oxazolidinones, streptogramins, polymyxins, sulphonamides, glycopeptides, quinolones and tetracyclines.

 

The increase in drug-resistant pathogens is a consequence of multiple factors, including but not limited to high rates of antimicrobial prescriptions, antibiotic mismanagement in the form of self-medication or interruption of therapy, and large-scale antibiotic use as growth promotors in livestock farming. For example, 60% of the antibiotics sold to the USA food industry are also used as therapeutics in humans. To further complicate matters, it is estimated that $200 million is required for a molecule to reach commercialization, with the risk of antimicrobial resistance rapidly developing, crippling its clinical application, or on the opposing end, a new antibiotic might be so effective it is only used as a last resort therapeutic, thus not widely commercialized.

 

Besides a more efficient management of antibiotic use, there is a pressing need for new platforms capable of consistently and efficiently delivering new lead substances, which should attend their precursors impressively low rates of success, in today’s increasing drug resistance scenario. Antibiotic Discovery Platforms are aiming to screen large libraries, for instance the reservoir of untapped natural products, which is likely the next antibiotic ‘gold mine’. There is a void between phenotanypic screening (high-throughput) and omics-centered assays (high-information), where some mechanistic and molecular information complements antimicrobial activity, without the laborious and extensive application of various omics assays. The increasing need for antibiotics drives the relentless and continuous research on the foreground of antibiotic discovery. This is likely to expand our knowledge on the biological events underlying infectious diseases and, hopefully, result in better therapeutics that can swing the war on infectious diseases back in our favor.

 

During the genomics era came the target-based platform, mostly considered a failure due to limitations in translating drugs to the clinic. Therefore, cell-based platforms were re-instituted, and are still of the utmost importance in the fight against infectious diseases. Although the antibiotic pipeline is still lackluster, especially of new classes and novel mechanisms of action, in the post-genomic era, there is an increasingly large set of information available on microbial metabolism. The translation of such knowledge into novel platforms will hopefully result in the discovery of new and better therapeutics, which can sway the war on infectious diseases back in our favor.

 

References:

 

https://www.mdpi.com/2079-6382/8/2/45/htm

 

https://www.ncbi.nlm.nih.gov/pubmed/19515346

 

https://www.ajicjournal.org/article/S0196-6553(11)00184-2/fulltext

 

https://www.ncbi.nlm.nih.gov/pubmed/21700626

 

http://www.med.or.jp/english/journal/pdf/2009_02/103_108.pdf

 

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Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Protein kinase C (PKC) isozymes function as tumor suppressors in increasing contexts. These enzymes are crucial for a number of cellular activities, including cell survival, proliferation and migration — functions that must be carefully controlled if cells get out of control and form a tumor. In contrast to oncogenic kinases, whose function is acutely regulated by transient phosphorylation, PKC is constitutively phosphorylated following biosynthesis to yield a stable, autoinhibited enzyme that is reversibly activated by second messengers. Researchers at University of California San Diego School of Medicine found that another enzyme, called PHLPP1, acts as a “proofreader” to keep careful tabs on PKC.

 

The researchers discovered that in pancreatic cancer high PHLPP1 levels lead to low PKC levels, which is associated with poor patient survival. They reported that the phosphatase PHLPP1 opposes PKC phosphorylation during maturation, leading to the degradation of aberrantly active species that do not become autoinhibited. They discovered that any time an over-active PKC is inadvertently produced, the PHLPP1 “proofreader” tags it for destruction. That means the amount of PHLPP1 in patient’s cells determines his amount of PKC and it turns out those enzyme levels are especially important in pancreatic cancer.

 

This team of researchers reversed a 30-year paradigm when they reported evidence that PKC actually suppresses, rather than promotes, tumors. For decades before this revelation, many researchers had attempted to develop drugs that inhibit PKC as a means to treat cancer. Their study implied that anti-cancer drugs would actually need to do the opposite — boost PKC activity. This study sets the stage for clinicians to one day use a pancreatic cancer patient’s PHLPP1/PKC levels as a predictor for prognosis, and for researchers to develop new therapeutic drugs that inhibit PHLPP1 and boost PKC as a means to treat the disease.

 

The ratio — high PHLPP1/low PKC — correlated with poor prognoses: no pancreatic patient with low PKC in the database survived longer than five-and-a-half years. On the flip side, 50 percent of the patients with low PHLPP1/high PKC survived longer than that. While still in the earliest stages, the researchers hope that this information might one day aid pancreatic diagnostics and treatment. The researchers are next planning to screen chemical compounds to find those that inhibit PHLPP1 and restore PKC levels in low-PKC-pancreatic cancer cells in the lab. These might form the basis of a new therapeutic drug for pancreatic cancer.

 

References:

 

https://health.ucsd.edu/news/releases/Pages/2019-03-20-two-enzymes-linked-to-pancreatic-cancer-survival.aspx?elqTrackId=b6864b278958402787f61dd7b7624666

 

https://www.ncbi.nlm.nih.gov/pubmed/30904392

 

https://www.ncbi.nlm.nih.gov/pubmed/29513138

 

https://www.ncbi.nlm.nih.gov/pubmed/18511290

 

https://www.ncbi.nlm.nih.gov/pubmed/28476658

 

https://www.ncbi.nlm.nih.gov/pubmed/28283201

 

https://www.ncbi.nlm.nih.gov/pubmed/24231509

 

https://www.ncbi.nlm.nih.gov/pubmed/28112438

 

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Changes in Levels of Sex Hormones and N-Terminal Pro–B-Type Natriuretic Peptide as Biomarker for Cardiovascular Diseases

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Considerable differences exist in the prevalence and manifestation of atherosclerotic cardiovascular disease (CVD) and heart failure (HF) between men and women. Premenopausal women have a lower risk of CVD and HF compared with men; however, this risk increases after menopause. Sex hormones, particularly androgens, are associated with CVD risk factors and events and have been postulated to mediate the observed sex differences in CVD.

 

B-type natriuretic peptides (BNPs) are secreted from cardiomyocytes in response to myocardial wall stress. BNP plays an important role in cardiovascular remodelling and volume homeostasis. It exerts numerous cardioprotective effects by promoting vasodilation, natriuresis, and ventricular relaxation and by antagonizing fibrosis and the effects of the renin-angiotensin-aldosterone system. Although the physiological role of BNP is cardioprotective, pathologically elevated N-terminal pro–BNP (NT-proBNP) levels are used clinically to indicate left ventricular hypertrophy, dysfunction, and myocardial ischemia. Higher NT-proBNP levels among individuals free of clinical CVD are associated with an increased risk of incident CVD, HF, and cardiovascular mortality.

 

BNP and NT-proBNP levels are higher in women than men in the general population. Several studies have proposed the use of sex- and age-specific reference ranges for BNP and NT-proBNP levels, in which reference limits are higher for women and older individuals. The etiology behind this sex difference has not been fully elucidated, but prior studies have demonstrated an association between sex hormones and NT-proBNP levels. Recent studies measuring endogenous sex hormones have suggested that androgens may play a larger role in BNP regulation by inhibiting its production.

 

Data were collected from a large, multiethnic community-based cohort of individuals free of CVD and HF at baseline to analyze both the cross-sectional and longitudinal associations between sex hormones [total testosterone (T), bioavailable T, freeT, dehydroepiandrosterone (DHEA), SHBG, and estradiol] and NT-proBNP, separately for women and men. It was found that a more androgenic pattern of sex hormones was independently associated with lower NT-proBNP levels in cross-sectional analyses in men and postmenopausal women.

 

This association may help explain sex differences in the distribution of NT-proBNP and may contribute to the NP deficiency in men relative to women. In longitudinal analyses, a more androgenic pattern of sex hormones was associated with a greater increase in NT-proBNP levels in both sexes, with a more robust association among women. This relationship may reflect a mechanism for the increased risk of CVD and HF seen in women after menopause.

 

Additional research is needed to further explore whether longitudinal changes in NT-proBNP levels seen in our study are correlated with longitudinal changes in sex hormones. The impact of menopause on changes in NT-proBNP levels over time should also be explored. Furthermore, future studies should aim to determine whether sex hormones directly play a role in biological pathways of BNP synthesis and clearance in a causal fashion. Lastly, the dual role of NTproBNP as both

  • a cardioprotective hormone and
  • a biomarker of CVD and HF, as well as
  • the role of sex hormones in delineating these processes,

should be further explored. This would provide a step toward improved clinical CVD risk stratification and prognostication based on

  • sex hormone and
  • NT-proBNP levels.

 

References:

 

https://www.medpagetoday.com/clinical-connection/cardio-endo/76480?xid=NL_CardioEndoConnection_2018-12-27

 

https://www.ncbi.nlm.nih.gov/pubmed/30137406

 

https://www.ncbi.nlm.nih.gov/pubmed/22064958

 

https://www.ncbi.nlm.nih.gov/pubmed/24036936

 

https://www.ncbi.nlm.nih.gov/pubmed/19854731

 

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Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Once herpes simplex infects a person, the virus goes into hiding inside nerve cells, hibernating there for life, periodically waking up from its sleep to reignite infection, causing cold sores or genital lesions to recur. Research from Harvard Medical School showed that the virus uses a host protein called CTCF, or cellular CCCTC-binding factor, to display this type of behavior. Researchers revealed with experiments on mice that CTCF helps herpes simplex regulate its own sleep-wake cycle, enabling the virus to establish latent infections in the body’s sensory neurons where it remains dormant until reactivated. Preventing that latency-regulating protein from binding to the virus’s DNA, weakened the virus’s ability to come out of hiding.

 

Herpes simplex virus’s ability to go in and out of hiding is a key survival strategy that ensures its propagation from one host to the next. Such symptom-free latency allows the virus to remain out of the reach of the immune system most of the time, while its periodic reactivation ensures that it can continue to spread from one person to the next. On one hand, so-called latency-associated transcript genes, or LAT genes, turn off the transcription of viral RNA, inducing the virus to go into hibernation, or latency. On the other hand, a protein made by a gene called ICP0 promotes the activity of genes that stimulate viral replication and causes active infection.

 

Based on these earlier findings, the new study revealed that this balancing act is enabled by the CTCF protein when it binds to the viral DNA. Present during latent or dormant infections, CTCF is lost during active, symptomatic infections. The researchers created an altered version of the virus that lacked two of the CTCF binding sites. The absence of the binding sites made no difference in early-stage or acute infections. Similar results were found in infected cultured human nerve cells (trigeminal ganglia) and infected mice model. The researchers concluded that the mutant virus was found to have significantly weakened reactivation capacity.

 

Taken together, the experiments showed that deleting the CTCF binding sites weakened the virus’s ability to wake up from its dormant state thereby establishing the evidence that the CTCF protein is a key regulator of sleep-wake cycle in herpes simplex infections.

 

References:

 

https://www.ncbi.nlm.nih.gov/pubmed/29437926

 

https://hms.harvard.edu/news/viral-hideout?utm_source=Silverpop

 

https://www.ncbi.nlm.nih.gov/pubmed/30110885

 

https://www.ncbi.nlm.nih.gov/pubmed/30014861

 

https://www.ncbi.nlm.nih.gov/pubmed/18264117

 

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  1. Lungs can supply blood stem cells and also produce platelets: Lungs, known primarily for breathing, play a previously unrecognized role in blood production, with more than half of the platelets in a mouse’s circulation produced there. Furthermore, a previously unknown pool of blood stem cells has been identified that is capable of restoring blood production when bone marrow stem cells are depleted.

 

  1. A new drug for multiple sclerosis: A new multiple sclerosis (MS) drug, which grew out of the work of UCSF (University of California, San Francisco) neurologist was approved by the FDA. Ocrelizumab, the first drug to reflect current scientific understanding of MS, was approved to treat both relapsing-remitting MS and primary progressive MS.

 

  1. Marijuana legalized – research needed on therapeutic possibilities and negative effects: Recreational marijuana will be legal in California starting in January, and that has brought a renewed urgency to seek out more information on the drug’s health effects, both positive and negative. UCSF scientists recognize marijuana’s contradictory status: the drug has proven therapeutic uses, but it can also lead to tremendous public health problems.

 

  1. Source of autism discovered: In a finding that could help unlock the fundamental mysteries about how events early in brain development lead to autism, researchers traced how distinct sets of genetic defects in a single neuronal protein can lead to either epilepsy in infancy or to autism spectrum disorders in predictable ways.

 

  1. Protein found in diet responsible for inflammation in brain: Ketogenic diets, characterized by extreme low-carbohydrate, high-fat regimens are known to benefit people with epilepsy and other neurological illnesses by lowering inflammation in the brain. UCSF researchers discovered the previously undiscovered mechanism by which a low-carbohydrate diet reduces inflammation in the brain. Importantly, the team identified a pivotal protein that links the diet to inflammatory genes, which, if blocked, could mirror the anti-inflammatory effects of ketogenic diets.

 

  1. Learning and memory failure due to brain injury is now restorable by drug: In a finding that holds promise for treating people with traumatic brain injury, an experimental drug, ISRIB (integrated stress response inhibitor), completely reversed severe learning and memory impairments caused by traumatic brain injury in mice. The groundbreaking finding revealed that the drug fully restored the ability to learn and remember in the brain-injured mice even when the animals were initially treated as long as a month after injury.

 

  1. Regulatory T cells induce stem cells for promoting hair growth: In a finding that could impact baldness, researchers found that regulatory T cells, a type of immune cell generally associated with controlling inflammation, directly trigger stem cells in the skin to promote healthy hair growth. An experiment with mice revealed that without these immune cells as partners, stem cells cannot regenerate hair follicles, leading to baldness.

 

  1. More intake of good fat is also bad: Liberal consumption of good fat (monounsaturated fat) – found in olive oil and avocados – may lead to fatty liver disease, a risk factor for metabolic disorders like type 2 diabetes and hypertension. Eating the fat in combination with high starch content was found to cause the most severe fatty liver disease in mice.

 

  1. Chemical toxicity in almost every daily use products: Unregulated chemicals are increasingly prevalent in products people use every day, and that rise matches a concurrent rise in health conditions like cancers and childhood diseases, Thus, researcher in UCSF is working to understand the environment’s role – including exposure to chemicals – in health conditions.

 

  1. Cytomegalovirus found as common factor for diabetes and heart disease in young women: Cytomegalovirus is associated with risk factors for type 2 diabetes and heart disease in women younger than 50. Women of normal weight who were infected with the typically asymptomatic cytomegalovirus, or CMV, were more likely to have metabolic syndrome. Surprisingly, the reverse was found in those with extreme obesity.

 

References:

 

https://www.ucsf.edu/news/2017/12/409241/most-popular-science-stories-2017

 

https://www.ucsf.edu/news/2017/03/406111/surprising-new-role-lungs-making-blood

 

https://www.ucsf.edu/news/2017/03/406296/new-multiple-sclerosis-drug-ocrelizumab-could-halt-disease

 

https://www.ucsf.edu/news/2017/06/407351/dazed-and-confused-marijuana-legalization-raises-need-more-research

 

https://www.ucsf.edu/news/2017/01/405631/autism-researchers-discover-genetic-rosetta-stone

 

https://www.ucsf.edu/news/2017/09/408366/how-ketogenic-diets-curb-inflammation-brain

 

https://www.ucsf.edu/news/2017/07/407656/drug-reverses-memory-failure-caused-traumatic-brain-injury

 

https://www.ucsf.edu/news/2017/05/407121/new-hair-growth-mechanism-discovered

 

https://www.ucsf.edu/news/2017/06/407536/go-easy-avocado-toast-good-fat-can-still-be-bad-you-research-shows

 

https://www.ucsf.edu/news/2017/06/407416/toxic-exposure-chemicals-are-our-water-food-air-and-furniture

 

https://www.ucsf.edu/news/2017/02/405871/common-virus-tied-diabetes-heart-disease-women-under-50

 

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Medical Scientific Discoveries for the 21st Century & Interviews with Scientific Leaders at https://www.amazon.com/dp/B078313281 – electronic Table of Contents 

Author, Curator and Editor: Larry H Bernstein, MD, FCAP

Available on Kindle Store @ Amazon.com since 12/9/2017

List of Contributors & Contributors’ Biographies

Volume Author, Curator and Editor

Larry H Bernstein, MD, FCAP

Preface, all Introductions, all Summaries and Epilogue

Part One:

1.4, 1.5, 1.6, 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.2.1, 2.2.2, 2.2.3, 2.3, 2.4, 2.4.1, 2.4.2, 2.5, 2.6.1, 2.6.2, 2.6.3, 2.6.4, 2.7, 2.8, 2.9, 2.10, 3.1, 3.2, 3.3, 3.4, 4.1, 4.2, 4.3

Part Two:

5.2, 5.3, 5.6, 6.1.2, 6.1.4, 6.2.1, 6.2.2, 6.3.2, 6.3.4, 6.3.5, 6.3.6, 6.3.8, 6.3.10, 6.4.1, 6.4.2, 6.5.1.2, 6.5.1.3, 6.5.2.2, 7.1, 7.2, 7.3, 7.4, 7.5, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 8.9.1, 8.9.3, 8.9.4, 8.9.5, 8.9.6, 8.10.1, 8.10.2, 8.10.3, 8.10.4, 9.2, 9.3, 9.5, 9.6, 9.7, 9.8, 9.9, 9.10, 9.11, 9.12, 9.13, 9.14, 9.15, 9.16, 10.2, 10.5, 10.6, 10.7, 10.8, 10.10, 10.11, 11.1, 11.2, 11.3, 11.5, 11.6, 11.7, 12.1, 12.2, 12.3, 12.4, 12.5, 12.7, 12.8, 12.9, 12.10, 12.11, 12.12, 13.1, 13.2, 13.3, 13.6, 13.12, 13.13, 14.1, 14.2

Guest Authors:

Pnina Abir-Am, PhD Part Two: 6.1.1

Stephen J Williams, PhDPart Two: 6.2.6, 6.5.2.2, 10.4, 10.9, 13.4

Aviva Lev-Ari, PhD, RN:

Part One:

1.1, 1.2, 1.3, 1.4, 1.5, 1.7, 2.2.1, 2.3

Part Two:

5.1, 5.4, 5.5, 5.7, 5.8, 5.9, 5.10, 5.11, 6.1.3, 6.2.3, 6.2.4, 6.2.5, 6.3.1, 6.3.3, 6.3.7, 6.3.9, 6.4.3, 6.5.1.1, 6.5.2.1, 6.5.2.2, 6.5.3.1, 6.5.4, 6.5.5, 6,5,6, 8.9.2, 8.10.2, 9.1, 9.4, 10.1, 10.3, 11.4, 12.6, 13.5, 13.7, 13.8, 13.9, 13.10, 13.11

Adam Sonnenberg, BSC, MSc(c)Part Two: 13.9

 

electronic Table of Contents

PART ONE:

Physician as Authors, Writers in Medicine and Educator in Public Health

 

Chapter 1: Physicians as Authors

Introduction

1.1  The Young Surgeon and The Retired Pathologist: On Science, Medicine and HealthCare Policy – Best writers Among the WRITERS

1.2 Atul Gawande: Physician and Writer

1.3 Editorial & Publication of Articles in e-Books by  Leaders in Pharmaceutical Business Intelligence:  Contributions of Larry H Bernstein, MD, FCAP

1.4 Abraham Verghese, MD, Physician and Notable Author

1.5 Eric Topol, M.D.

1.6 Gregory House, MD

1.7 Peter Mueller, MD  Professor of Radiology @MGH & HMS – 2015 Synergy’s Honorary Award Recipient

Summary

Chapter 2: Professional Recognition

Introduction

2.1 Proceedings

2.1.1 Research Presentations

2.1.2 Proceedings of the NYAS

2.1.3 Cold Spring Harbor Conference Meetings

2.1.4 Young Scientist Seminars

2.2 Meet Great Minds

2.2.1 Meet the Laureates

2.2.2 Richard Feynman, Genius and Laureate

2.2.3 Fractals and Heat Energy

2.3 MacArthur Foundation Awards

2.4 Women’s Contributions went beyond Rosie the Riveter

2.4.1 Secret Maoist Chinese Operation Conquered Malaria

2.4.2 Antiparasite Drug Developers Win Nobel

2.5 Impact Factors and Achievement

2.6   RAPsodisiac Medicine

2.6.1 Outstanding-achievements-in-radiology-or-radiotherapy

2.6.2 Outstanding-achievement-in-anesthesiology

2.6.3 Outstanding-achievement-in-pathology

2.6.4 Topics in Pathology – Special Issues from Medscape Pathology

2.7 How to win the Nobel Prize

2.8 Conversations about Medicine

2.9 Current Advances in Medical Technology

2.10 Atul Butte, MD, PhD

Summary

Chapter 3:  Medical and Allied Health Sciences Education

Introduction

3.1 National Outstanding Medical Student Award Winners

3.2 Outstanding Awards in Medical Education

3.3 Promoting Excellence in Physicians and Nurses

3.4 Excellence in mentoring

Summary

Chapter 4: Science Teaching in Math and Technology (STEM)

Introduction

4.1 Science Teaching in Math and Technology

4.2 Television as a Medium for Science Education

4.2.1 Science Discovery TV

4.3 From Turing to Watson

Summary

PART TWO:

Medical Scientific Discoveries Interviews with Scientific Leaders

Chapter 5: Cardiovascular System

Introduction

5.1 Physiologist, Professor Lichtstein, Chair in Heart Studies at The Hebrew University elected Dean of the Faculty of Medicine at The Hebrew University of Jerusalem

5.2 Mitochondrial Dysfunction and Cardiac Disorders

5.3 Notable Contributions to Regenerative Cardiology

5.4 For Accomplishments in Cardiology and Cardiovascular Diseases: The Arrigo Recordati International Prize for Scientific Research

5.5 Becoming a Cardiothoracic Surgeon: An Emerging Profile in the Surgery Theater and through Scientific Publications

5.6 Diagnostics and Biomarkers: Novel Genomics Industry Trends vs Present Market Conditions and Historical Scientific Leaders Memoirs

5.7 CVD Prevention and Evaluation of Cardiovascular Imaging Modalities: Coronary Calcium Score by CT Scan Screening to justify or not the Use of Statin

5.8 2013 as A Year of Revolutionizing Medicine and Top 11 Cardiology Stories

5.9 Bridging the Gap in Medical Innovations – Elazer Edelman @ TEDMED 2013

5.10 Development of a Pancreatobiliary Chemotherapy Eluting Stent for Pancreatic Ductal Adenocarcinoma PIs: Jeffrey Clark (MGH), Robert Langer (Koch), Elazer Edelman (Harvard:MIT HST Program)

5.11 Publications on Heart Failure by Prof. William Gregory Stevenson, M.D., BWH

Summary

Chapter 6: Genomics

Introduction
6.1 Genetics before the Human Genome Project

6.1.1 Why did Pauling Lose the “Race” to James Watson and Francis Crick? How Crick Describes his Discovery in a Letter to his Son

6.1.2 John Randall’s MRC Research Unit and Rosalind Franklin’s role at Kings College

6.1.3 Interview with the co-discoverer of the structure of DNA: Watson on The Double Helix and his changing view of Rosalind Franklin

6.1.4 The Initiation and Growth of Molecular Biology and Genomics, Part I

6.2 The Human Genome Project: Articles of Note  @ pharmaceuticalintelligence.com by multiple authors

6.2.1 CRACKING THE CODE OF HUMAN LIFE: The Birth of BioInformatics & Computational Genomics

6.2.2 What comes after finishing the Euchromatic Sequence of the Human Genome?

6.2.3 Human Genome Project – 10th Anniversary: Interview with Kevin Davies, PhD – The $1000 Genome

6.2.4 University of California Santa Cruz’s Genomics Institute will create a Map of Human Genetic Variations

6.2.5 Exceptional Genomes: The Process to find them

6.2.6 Multiple Lung Cancer Genomic Projects Suggest New Targets, Research Directions for Non-Small Cell Lung Cancer

6.3 The Impact of Genome Sequencing on Biology and Medicine

6.3.1 Genomics in Medicine – Establishing a Patient-Centric View of Genomic Data

6.3.2 Modification of genes by homologous recombination – Mario Capecchi, Martin Evans, Oliver Smithies

6.3.3 AAAS February 14-18, 2013, Boston: Symposia – The Science of Uncertainty in Genomic Medicine

6.3.4 The Metabolic View of Epigenetic Expression

6.3.5  Pharmacogenomics

6.3.6 Neonatal Pathophysiology

6.3.7 Genetics of Conduction Disease: Atrioventricular (AV) Conduction Disease (block): Gene Mutations – Transcription, Excitability, and Energy Homeostasis

6.3.8 3D mapping of genome in combine FISH and RNAi

6.3.9 Human Variome Project: encyclopedic catalog of sequence variants indexed to the human genome sequence

6.3.10 DNA mutagenesis and DNA repair

6.4 Scientific Leadership Recognition for Contributions to Genomics

6.4.1 Interview with Elizabeth H. Blackburn, Carol W. Greider and Jack W. Szostak (44 minutes)

6.4.2 DNA Repair Pioneers Win Nobel – Tomas Lindahl, Paul Modrich, and Aziz Sancar 2015 Nobel Prize in Chemistry for the mechanisms of DNA repair

6.4.3  Richard Lifton, MD, PhD of Yale University and Howard Hughes Medical Institute: Recipient of 2014 Breakthrough Prizes Awarded in Life Sciences for the Discovery of Genes and Biochemical Mechanisms that cause Hypertension

6.5 Contemporary Field Leaders in Genomics

6.5.1 ROBERT LANGER

6.5.1.1 2014 Breakthrough Prizes Awarded in Fundamental Physics and Life Sciences for a Total of $21 Million – MIT’s Robert Langer gets $3 Million

6.5.1.2 National Medal of Science – 2006 Robert S. Langer

6.5.1.3  Confluence of Chemistry, Physics, and Biology

6.5.2 JENNIFER DOUDNA

6.5.2.1 Jennifer Doudna, cosmology teams named 2015 Breakthrough Prize winners

6.5.2.2 UPDATED – Medical Interpretation of the Genomics Frontier – CRISPR – Cas9: Gene Editing Technology for New Therapeutics

6.5.3 ERIC LANDER

6.5.3.1  2012 Harvey Prize in April 30: at the Technion-Israel Institute of Technology to Eric S. Lander @MIT & Eli Yablonovitch @UC, Berkeley

6.5.4 2013 Genomics: The Era Beyond the Sequencing of the Human Genome: Francis Collins, Craig Venter, Eric Lander, et al.

6.5.5 Recognitions for Contributions in Genomics by Dan David Prize Awards

6.5.6   65 Nobel Laureates meet 650 young scientists covering the fields of physiology and medicine, physics, and chemistry, 28 June – 3 July, 2015, Lindau & Mainau Island, Germany

Summary

Chapter 7: The RNAs

Introduction

7.1 RNA polymerase – molecular basis for DNA transcription – Roger Kornberg, MD

7.2  One gene, one protein – Charles Yanofsky

7.3 Turning genetic information into working proteins – James E. Darnell Jr.

7.4 Small but mighty RNAs – Victor Ambros, David Baulcombe, and Gary Ruvkun, Phillip A. Sharp

7.5 Stress-response gene networks – Nina V. Fedoroff

Summary

Chapter 8: Proteomics, Protein-folding, and Cell Regulation
Introduction.

8.1 The Life and Work of Allan Wilson

8.2 Proteomics

8.3 More Complexity in Protein Evolution

8.4 Proteins: An evolutionary record of diversity and adaptation

8.5 Heroes in Basic Medical Research – Leroy Hood

8.6 Ubiquitin researchers win Nobel – Ciechanover, Hershko, and Rose awarded for discovery of ubiquitin-mediated proteolysis

8.7 Buffering of genetic modules involved in tricarboxylic acid cycle metabolism provides homeostatic regulation

8.8 Dynamic Protein Profiling

8.9 Protein folding

8.9.1 Protein misfolding and prions – Susan L. Lindquist, Stanley B. Prusiner

8.9.2 A Curated Census of Autophagy-Modulating Proteins and Small Molecules Candidate Targets for Cancer Therapy

8.9.3 Voluntary and Involuntary S-Insufficiency

8.9.4 Transthyretin and Lean Body Mass in Stable and Stressed State

8.9.5 The matter of stunting in the Ganges Plains

8.9.6 Proteins, Imaging and Therapeutics

8.10 Protein Folding and Vesicle Cargo

8.10.1 Heat Shock Proteins (HSP) and Molecular Chaperones

8.10.2 Collagen-binding Molecular Chaperone HSP47: Role in Intestinal Fibrosis – colonic epithelial cells and sub epithelial myofibroblasts

8.10.3 Biology, Physiology and Pathophysiology of Heat Shock Proteins

8.10.4 The Role of Exosomes in Metabolic Regulation 


Summary

Chapter 9:  Neuroscience

Introduction

9.1 Nobel Prize in Physiology or Medicine 2013 for Cell Transport: James E. Rothman of Yale University; Randy W. Schekman of the University of California, Berkeley; and Dr. Thomas C. Südhof of Stanford University

9.2 Proteins that control neurotransmitter release – Richard H. Scheller

9.3 Heroes in Basic Medical Research – Robert J. Lefkowitz

9.4 MIND AND MEMORY: BIOLOGICAL AND DIGITAL – 2014 Dan David Prize Symposium

9.5 A new way of moving – Michael Sheetz, James Spudich, Ronald Vale

9.6 Role the basal ganglia

9.7 The Neurogenetics of Language – Patricia Kuhl – 2015 George A. Miller Award

9.8 The structure of our visual system

9.9 Outstanding Achievement in Schizophrenia Research

9.10 George A. Miller, a Pioneer in Cognitive Psychology, Is Dead at 92

9.11 – To understand what happens in the brain to cause mental illness

9.12 Brain and Cognition

9.13 – To reduce symptoms of mental illness and retrain the brain

9.14 Behavior

9.15 Notable Papers in Neurosciences

9.16 Pyrroloquinoline quinone (PQQ) – an unproved supplement

Summary

Chapter 10: Microbiology & Immunology

Introduction

10.1 Reference Genes in the Human Gut Microbiome: The BGI Catalogue

10.2 Malnutrition in India, high newborn death rate and stunting of children age under five years

10.3 In His Own Words: Leonard Herzenberg, The Immunologist Who Revolutionized Research, Dies at 81

10.4 Heroes in Medical Research: Dr. Robert Ting, Ph.D. and Retrovirus in AIDS and Cancer

10.5 Tang Prize for 2014: Immunity and Cancer

10.6 Halstedian model of cancer progression

10.7 The History of Hematology and Related Sciences

10.8 Pathology Emergence in the 21st Century

10.9 Heroes in Medical Research: Barnett Rosenberg and the Discovery of Cisplatin

10.10  T cell-mediated immune responses & signaling pathways activated by TLRs – Bruce A. Beutler, Jules A. Hoffmann, Ralph M. Steinman

10.11 Roeder – the coactivator OCA-B, the first cell-specific coactivator, discovered by Roeder in 1992, is unique to immune system B cells

Summary

Chapter 11: Endocrine Hormones

Introduction

11.1 Obesity – 2010 Douglas L. ColemanJeffrey M. Friedman

11.2 Lonely Receptors: RXR – Jensen, Chambon, and Evans – Nuclear receptors provoke RNA production in response to steroid hormones

11.3 The Fred Conrad Koch Lifetime Achievement Award—the Society’s highest honor—recognizes the lifetime achievements and exceptional contributions of an individual to the field of endocrinology

11.4 Gerald D Aurbach Award for Outstanding Translational Research

11.5 Roy O. Greep Award for Outstanding Research in Endocrinology – Martin M. Matzuk

11.6 American Physiology Society Awards

11.7 Solomon Berson and Rosalyn Yalow

Summary

Chapter 12. Stem Cells

Introduction

12.1 Mature cells can be reprogrammed to become pluripotent – John Gurdon and Shinya Yamanaka

12.2 Observing the spleen colonies in mice and proving the existence of stem cells – Till and McCulloch

12.3 McEwen Award for Innovation: Irving Weissman, M.D., Stanford School of Medicine, and Hans Clevers, M.D., Ph.D., Hubrecht Institute

12.4 Developmental biology

12.5  CRISPR/Cas-mediated genome engineering – Rudolf Jaenisch

12.6 Ribozymes and RNA Machines –  Work of Jennifer A. Doudna

12.7 Ralph Brinster, ‘Father of Transgenesis’

12.8 Targeted gene modification

12.9 Stem Cells and Cancer

12.10 ALPSP Awards

12.11 Eppendorf Award for Young European Investigators

12.12 Breaking news about genomic engineering, T2DM and cancer treatments

Summary
Chapter 13: 3D Printing and Medical Application

Introduction

13.1 3D Printing

13.2 What is 3D printing?

13.3 The Scientist Who Is Making 3D Printing More Human

13.4 Join These Medical 3D Printing Groups on Twitter and LinkedIn for great up to date news

13.5 Neri Oxman and her Mediated Matter group @MIT Media Lab have developed a technique for 3D-printing Molten Glass

13.6 The ‘chemputer’ that could print out any drug

13.7 3-D-Bioprinting in use to Create Cardiac Living Tissue: Print your Heart out

13.8 LPBI’s Perspective on Medical and Life Sciences Applications – 3D Printing: BioInks, BioMaterials-BioPolymer

13.9 Medical MEMS, Sensors and 3D Printing: Frontier in Process Control of BioMaterials

13.10 NIH and FDA on 3D Printing in Medical Applications: Views for On-demand Drug Printing, in-Situ direct Tissue Repair and Printed Organs for Live Implants

13.11 ‘Pop-up’ fabrication technique trumps 3D printing

13.12 Augmentation of the ONTOLOGY of the 3D Printing Research

13.13 Superresolution Microscopy

Summary

Chapter 14: Synthetic Medicinal Chemistry

Introduction

14.1 Insights in Biological and Synthetic Medicinal Chemistry

14.2 Breakthrough work in cancer

Summary to Part Two

Volume Summary and Conclusions

EPILOGUE

 

 

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Familial transthyretin amyloid polyneuropathy

Curator: Larry H. Bernstein, MD, FCAP

 

UPDATED on 6/3/2020

Treatment of Cardiac Transthyretin Amyloidosis

Authors:
Emdin M, Aimo A, Rapezzi C, et al.
Citation:
Treatment of Cardiac Transthyretin Amyloidosis: An Update. Eur Heart J 2019;40:3699-3706.

The following are key points to remember from this update on the treatment of cardiac transthyretin amyloidosis:

  1. Transthyretin (TTR) is a highly conserved protein involved in transportation of thyroxine (T4) and retinol-binding protein. TTR is synthesized mostly by the liver and is rich in beta strands with an intrinsic propensity to aggregate into insoluble amyloid fibers, which deposit within tissue leading to the development of TTR-related amyloidosis (ATTR). ATTR can follow the deposition of either variant TTR (ATTRv, previously known as mutant ATTR) or wild type TTR (ATTRwt).
  2. Cardiac ATTR has a favorable survival rate compared to light chain (AL) amyloidosis, with a median survival of 75 versus 11 months. However, ATTR cardiomyopathy is a progressive disorder but newer therapeutic options include tafamidis (positive phase 3 clinical trial), and possibly patisiran and inotersen.

Inhibition of the Synthesis of Mutated Transthyretin

  1. Liver transplantation removes the source of mutated TTR molecules and prolongs survival, with a 20-year survival of 55.3%. However, tissue accumulation of TTR can continue after liver transplantation because TTR amyloid fibers promote subsequent deposition of ATTRwt. Combined liver–heart transplantation is feasible in younger patients with ATTRv cardiomyopathy and a small series suggests better prognosis than cardiac transplantation.
  2. Inhibition of TTR gene expression: Patisiran is a small interfering RNA blocking the expression of both variant and wt TTR. On the basis of the APOLLO trial, it was approved for therapy of adults with ATTRv-related polyneuropathy both in the United States and European Union. In this trial, patisiran promoted favorable myocardial remodeling based on echocardiographic and N-terminal B-type natriuretic peptide (NT-BNP) changes (this effect was not demonstrated for inotersen) and is still under investigation for tafamidis.
  3. Antisense oligonucleotides inotersen inhibits the production of both variant and wt TTR. Based on the findings of the NEURO-TTR trial, the Food and Drug Administration (FDA) approved this agent for patients with ATTRv-related polyneuropathy. In the NEURO-TTR trial, cardiomyopathy was present in 63%, but the study was not powered to measure effects of inotersen on heart disease. Inotersen can cause thrombocytopenia and must be used cautiously with bleeding risk.

Tetramer Stabilization

  1. Selective stabilizers include tafamidis and AG10. Tafamidis is a benzoxazole and a small molecule that inhibits the dissociation of TTR tetramers by binding the T4-binding sites. The phase ATTR-ACT study showed that when comparing the pooled tafamidis arms (80 and 20 mg) with the placebo arm, tafamidis was associated with lower all-cause mortality than placebo (78 of 264 [29.5%] vs. 76 of 177 [42.9%]; hazard ratio, 0.70; 95% confidence interval, 0.51-0.96) and a lower rate of cardiovascular hospitalizations. Based on the results of the ATTR-ACT trial, it has received Breakthrough Therapy designation from the FDA for treatment of ATTR cardiomyopathy.
  2. Nonselective agents: Diflunisal, a nonsteroidal anti-inflammatory drug, is reported to stabilize TTR tetramers. More studies are needed to confirm its clinical efficacy.

Inhibition of Oligomer Aggregation and Oligomer Disruption

  1. Epigallocatechin gallate is the most abundant catechin in green tea. One single-center open-label 12-month study did not show survival benefits or any change in echocardiographic parameters or NT-BNP compared to baseline.

Degradation and Reabsorption of Amyloid Fibers

  1. Doxycycline-taurosodeoxycholic acid (TUDCA) has been evaluated in two small studies and the results appear to be modest. More data are needed to confirm its efficacy.
  2. Antibodies targeting serum amyloid P protein or amyloid fibrils: Patient enrollment for miridesap followed by anti-SAP antibodies was suspended, and this approach is not being evaluated currently. However, a monoclonal antibody designed to specifically target TTR amyloid deposits (PRX004) has entered clinical evaluation, with an ongoing phase 1 study on ATTRv.

Supportive Treatment of Cardiac Involvement

  1. Drug therapies: Although angiotensin-converting enzyme (ACE) inhibitors/angiotensin-receptor blockers (ARBs) and beta-blockers may have been poorly tolerated in the ATTR-ACT trial, 30% of the patients were on ACE inhibitors/ARBs. There are no data with digoxin in TTR amyloid, and non-dihydropyridine calcium channel blockers are contraindicated due to negative inotropy.
  2. Implantable cardioverter-defibrillators (ICDs): In one study, which included 53 patients with amyloid, ICD shocks occurred exclusively in the AL amyloid group and none in the TTR amyloid patients. Higher defibrillation thresholds and complication rates are of concern.
  3. Cardiac pacing: In a large series of ATTRv-related polyneuropathy (n = 262), a pacemaker was implanted in 110 patients with His ventricular interval >700 ms. The authors recommend that any conduction disturbance on 12-lead electrocardiogram (ECG) warrants further investigation with Holter monitoring to determine candidacy for a pacemaker.
  4. Left ventricular assist device (LVAD): Although an LVAD is technically feasible, it is associated with high short-term mortality and worse outcomes than in dilated cardiomyopathy.
  5. Cardiac transplantation: This is a valuable option for patients with end-stage heart failure when significant extracardiac disease is excluded. In one study with 10 patients, only episodes of amyloid recurrence occurred.

This is an outstanding overview of this topic and recommended reading for anyone who cares for patients with cardiac transthyretin amyloid.

 

First-Ever Evidence that Patisiran Reduces Pathogenic, Misfolded TTR Monomers and Oligomers in FAP Patients

We reported data from our ongoing Phase 2 open-label extension (OLE) study of patisiran, an investigational RNAi therapeutic targeting transthyretin (TTR) for the treatment of TTR-mediated amyloidosis (ATTR amyloidosis) patients with familial amyloidotic polyneuropathy (FAP). Alnylam scientists and collaborators from The Scripps Research Institute and Misfolding Diagnostics, Inc. were able to measure the effects of patisiran on pathogenic, misfolded TTR monomers and oligomers in FAP patients. Results showed a rapid and sustained reduction in serum non-native conformations of TTR (NNTTR) of approximately 90%. Since NNTTR is pathogenic in ATTR amyloidosis and the level of NNTTR reduction correlated with total TTR knockdown, these results provide direct mechanistic evidence supporting the therapeutic hypothesis that TTR knockdown has the potential to result in clinical benefit. Furthermore, complete 12-month data from all 27 patients that enrolled in the patisiran Phase 2 OLE study showed sustained mean maximum reductions in total serum TTR of 91% for over 18 months and a mean 3.1-point decrease in mNIS+7 at 12 months, which compares favorably to an estimated increase in mNIS+7 of 13 to 18 points at 12 months based upon analysis of historical data sets in untreated FAP patients with similar baseline characteristics. Importantly, patisiran administration continues to be generally well tolerated out to 21 months of treatment.

Read our press release

View the non-native TTR poster (480 KB PDF)

View the complete 12-month patisiran Phase 2 OLE data presentation (620 KB PDF)

We are encouraged by these new data that provide continued support for our hypothesis that patisiran has the potential to halt neuropathy progression in patients with FAP. If these results are replicated in a randomized, double-blind, placebo-controlled study, we believe that patisiran could emerge as an important treatment option for patients suffering from this debilitating, progressive and life-threatening disease.

 

Hereditary ATTR Amyloidosis with Polyneuropathy (hATTR-PN)

ATTR amyloidosis is a progressive, life-threatening disease caused by misfolded transthyretin (TTR) proteins that accumulate as amyloid fibrils in multiple organs, but primarily in the peripheral nerves and heart. ATTR amyloidosis can lead to significant morbidity, disability, and mortality. The TTR protein is produced primarily in the liver and is normally a carrier for retinol binding protein – one of the vehicles used to transport vitamin A around the body.  Mutations in the TTR gene cause misfolding of the protein and the formation of amyloid fibrils that typically contain both mutant and wild-type TTR that deposit in tissues such as the peripheral nerves and heart, resulting in intractable peripheral sensory neuropathy, autonomic neuropathy, and/or cardiomyopathy.

Click to Enlarge

 

ATTR represents a major unmet medical need with significant morbidity and mortality. There are over 100 reported TTR mutations; the particular TTR mutation and the site of amyloid deposition determine the clinical manifestations of the disease whether it is predominantly symptoms of neuropathy or cardiomyopathy.

Specifically, hereditary ATTR amyloidosis with polyneuropathy (hATTR-PN), also known as familial amyloidotic polyneuropathy (FAP), is an inherited, progressive disease leading to death within 5 to 15 years. It is due to a mutation in the transthyretin (TTR) gene, which causes misfolded TTR proteins to accumulate as amyloid fibrils predominantly in peripheral nerves and other organs. hATTR-PN can cause sensory, motor, and autonomic dysfunction, resulting in significant disability and death.

It is estimated that hATTR-PN, also known as FAP, affects approximately 10,000 people worldwide.  Patients have a life expectancy of 5 to 15 years from symptom onset, and the only treatment options for early stage disease are liver transplantation and TTR stabilizers such as tafamidis (approved in Europe) and diflunisal.  Unfortunately liver transplantation has limitations, including limited organ availability as well as substantial morbidity and mortality. Furthermore, transplantation eliminates the production of mutant TTR but does not affect wild-type TTR, which can further deposit after transplantation, leading to cardiomyopathy and worsening of neuropathy. There is a significant need for novel therapeutics to treat patients who have inherited mutations in the TTR gene.

Our ATTR program is the lead effort in our Genetic Medicine Strategic Therapeutic Area (STAr) product development and commercialization strategy, which is focused on advancing innovative RNAi therapeutics toward genetically defined targets for the treatment of rare diseases with high unmet medical need.  We are developing patisiran (ALN-TTR02), an intravenously administered RNAi therapeutic, to treat the hATTR-PN form of the disease.

Patisiran for the Treatment hATTR-PN

APOLLO Phase 3 Trial

In 2012, Alnylam entered into an exclusive alliance with Genzyme, a Sanofi company, to develop and commercialize RNAi therapeutics, including patisiran and revusiran, for the treatment of ATTR amyloidosis in Japan and the broader Asian-Pacific region. In early 2014, this relationship was extended as a significantly broader alliance to advance RNAi therapeutics as genetic medicines. Under this new agreement, Alnylam will lead development and commercialization of patisiran in North America and Europe while Genzyme will develop and commercialize the product in the rest of world.

 

Hereditary ATTR Amyloidosis with Cardiomyopathy (hATTR-CM)

ATTR amyloidosis is a progressive, life-threatening disease caused by misfolded transthyretin (TTR) proteins that accumulate as amyloid fibrils in multiple organs, but primarily in the peripheral nerves and heart. ATTR amyloidosis can lead to significant morbidity, disability, and mortality. The TTR protein is produced primarily in the liver and is normally a carrier for retinol binding protein – one of the vehicles used to transport vitamin A around the body.  Mutations in the TTR gene cause misfolding of the protein and the formation of amyloid fibrils that typically contain both mutant and wild-type TTR that deposit in tissues such as the peripheral nerves and heart, resulting in intractable peripheral sensory neuropathy, autonomic neuropathy, and/or cardiomyopathy.

Click to Enlarge                            http://www.alnylam.com/web/assets/tetramer.jpg

ATTR represents a major unmet medical need with significant morbidity and mortality. There are over 100 reported TTR mutations; the particular TTR mutation and the site of amyloid deposition determine the clinical manifestations of the disease, whether it is predominantly symptoms of neuropathy or cardiomyopathy.

Specifically, hereditary ATTR amyloidosis with cardiomyopathy (hATTR-CM), also known as familial amyloidotic cardiomyopathy (FAC), is an inherited, progressive disease leading to death within 2 to 5 years. It is due to a mutation in the transthyretin (TTR) gene, which causes misfolded TTR proteins to accumulate as amyloid fibrils primarily in the heart. Hereditary ATTR amyloidosis with cardiomyopathy can result in heart failure and death.

While the exact numbers are not known, it is estimated hATTR-CM, also known as FAC affects at least 40,000 people worldwide.  hATTR-CM is fatal within 2 to 5 years of diagnosis and treatment is currently limited to supportive care.  Wild-type ATTR amyloidosis (wtATTR amyloidosis), also known as senile systemic amyloidosis, is a nonhereditary, progressive disease leading to death within 2 to 5 years. It is caused by misfolded transthyretin (TTR) proteins that accumulate as amyloid fibrils in the heart. Wild-type ATTR amyloidosis can cause cardiomyopathy and result in heart failure and death. There are no approved therapies for the treatment of hATTR-CM or SSA; hence there is a significant unmet need for novel therapeutics to treat these patients.

Our ATTR program is the lead effort in our Genetic Medicine Strategic Therapeutic Area (STAr) product development and commercialization strategy, which is focused on advancing innovative RNAi therapeutics toward genetically defined targets for the treatment of rare diseases with high unmet medical need.  We are developing revusiran (ALN-TTRsc), a subcutaneously administered RNAi therapeutic for the treatment of hATTR-CM.

Revusiran for the Treatment of hATTR-CM

ENDEAVOUR Phase 3 Trial

In 2012, Alnylam entered into an exclusive alliance with Genzyme, a Sanofi company, to develop and commercialize RNAi therapeutics, including patisiran and revusiran, for the treatment of ATTR amyloidosis in Japan and the broader Asian-Pacific region. In early 2014, this relationship was extended as a broader alliance to advance RNAi therapeutics as genetic medicines. Under this new agreement, Alnylam and Genzyme have agreed to co-develop and co-commercialize revusiran in North America and Europe, with Genzyme developing and commercializing the product in the rest of world. This broadened relationship on revusiran is aimed at expanding and accelerating the product’s global value.

Pre-Clinical Data and Advancement of ALN-TTRsc02 for Transthyretin-Mediated Amyloidosis

We presented pre-clinical data with ALN-TTRsc02, an investigational RNAi therapeutic targeting transthyretin (TTR) for the treatment of TTR-mediated amyloidosis (ATTR amyloidosis).  In pre-clinical studies, including those in non-human primates (NHPs), ALN-TTRsc02 achieved potent and highly durable knockdown of serum TTR of up to 99% with multi-month durability achieved after just a single dose, supportive of a potentially once quarterly dose regimen. Results from studies comparing TTR knockdown activity of ALN-TTRsc02 to that of revusiran showed that ALN-TTRsc02 has a markedly superior TTR knockdown profile.  Further, in initial rat toxicology studies, ALN-TTRsc02 was found to be generally well tolerated with no significant adverse events at doses as high as 100 mg/kg.

Read our press release

View the presentation

http://www.alnylam.com/product-pipeline/hereditary-attr-amyloidosis-with-cardiomyopathy/

 

Emerging Therapies for Transthyretin Cardiac Amyloidosis Could Herald a New Era for the Treatment of HFPEF

Oct 14, 2015   |  Adam Castano, MDDavid Narotsky, MDMathew S. Maurer, MD, FACC

http://www.acc.org/latest-in-cardiology/articles/2015/10/13/08/35/emerging-therapies-for-transthyretin-cardiac-amyloidosis#sthash.9xzc0rIe.dpuf

Heart failure with a preserved ejection fraction (HFPEF) is a clinical syndrome that has no pharmacologic therapies approved for this use to date. In light of failed medicines, cardiologists have refocused treatment strategies based on the theory that HFPEF is a heterogeneous clinical syndrome with different etiologies. Classification of HFPEF according to etiologic subtype may, therefore, identify cohorts with treatable pathophysiologic mechanisms and may ultimately pave the way forward for developing meaningful HFPEF therapies.1

A wealth of data now indicates that amyloid infiltration is an important mechanism underlying HFPEF. Inherited mutations in transthyretin cardiac amyloidosis (ATTRm) or the aging process in wild-type disease (ATTRwt) cause destabilization of the transthyretin (TTR) protein into monomers or oligomers, which aggregate into amyloid fibrils. These insoluble fibrils accumulate in the myocardium and result in diastolic dysfunction, restrictive cardiomyopathy, and eventual congestive heart failure (Figure 1). In an autopsy study of HFPEF patients, almost 20% without antemortem suspicion of amyloid had left ventricular (LV) TTR amyloid deposition.2 Even more resounding evidence for the contribution of TTR amyloid to HFPEF was a study in which 120 hospitalized HFPEF patients with LV wall thickness ≥12 mm underwent technetium-99m 3,3-diphosphono-1,2-propranodicarboxylic acid (99mTc-DPD) cardiac imaging,3,4 a bone isotope known to have high sensitivity and specificity for diagnosing TTR cardiac amyloidosis.5,6 Moderate-to-severe myocardial uptake indicative of TTR cardiac amyloid deposition was detected in 13.3% of HFPEF patients who did not have TTR gene mutations. Therefore, TTR cardiac amyloid deposition, especially in older adults, is not rare, can be easily identified, and may contribute to the underlying pathophysiology of HFPEF.

Figure 1

As no U.S. Food and Drug Administration-approved drugs are currently available for the treatment of HFPEF or TTR cardiac amyloidosis, the development of medications that attenuate or prevent TTR-mediated organ toxicity has emerged as an important therapeutic goal. Over the past decade, a host of therapies and therapeutic drug classes have emerged in clinical trials (Table 1), and these may herald a new direction for treating HFPEF secondary to TTR amyloid.

Table 1

TTR Silencers (siRNA and Antisense Oligonucleotides)

siRNA

Ribonucleic acid interference (RNAi) has surfaced as an endogenous cellular mechanism for controlling gene expression. Small interfering RNAs (siRNAs) delivered into cells can disrupt the production of target proteins.7,8 A formulation of lipid nanoparticle and triantennary N-acetylgalactosamine (GalNAc) conjugate that delivers siRNAs to hepatocytes is currently in clinical trials.9 Prior research demonstrated these GalNAc-siRNA conjugates result in robust and durable knockdown of a variety of hepatocyte targets across multiple species and appear to be well suited for suppression of TTR gene expression and subsequent TTR protein production.

The TTR siRNA conjugated to GalNAc, ALN-TTRSc, is now under active investigation as a subcutaneous injection in phase 3 clinical trials in patients with TTR cardiac amyloidosis.10 Prior phase 2 results demonstrated that ALN-TTRSc was generally well tolerated in patients with significant TTR disease burden and that it reduced both wild-type and mutant TTR gene expression by a mean of 87%. Harnessing RNAi technology appears to hold great promise for treating patients with TTR cardiac amyloidosis. The ability of ALN-TTRSc to lower both wild-type and mutant proteins may provide a major advantage over liver transplantation, which affects the production of only mutant protein and is further limited by donor shortage, cost, and need for immunosuppression.

Antisense Oligonucleotides

Antisense oligonucleotides (ASOs) are under clinical investigation for their ability to inhibit hepatic expression of amyloidogenic TTR protein. Currently, the ASO compound, ISIS-TTRRx, is under investigation in a phase 3 multicenter, randomized, double-blind, placebo-controlled clinical trial in patients with familial amyloid polyneuropathy (FAP).11 The primary objective is to evaluate its efficacy as measured by change in neuropathy from baseline relative to placebo. Secondary measures will evaluate quality of life (QOL), modified body mass index (mBMI) by albumin, and pharmacodynamic effects on retinol binding protein. Exploratory objectives in a subset of patients with LV wall thickness ≥13 mm without a history of persistent hypertension will examine echocardiographic parameters, N-terminal pro–B-type natriuretic peptide (NT-proBNP), and polyneuropathy disability score relative to placebo. These data will facilitate analysis of the effect of antisense oligonucleotide-mediated TTR suppression on the TTR cardiac phenotype with a phase 3 trial anticipated to begin enrollment in 2016.

TTR Stabilizers (Diflunisal, Tafamidis)

Diflunisal

Several TTR-stabilizing agents are in various stages of clinical trials. Diflunisal, a traditionally used and generically available nonsteroidal anti-inflammatory drug (NSAID), binds and stabilizes familial TTR variants against acid-mediated fibril formation in vitro and is now in human clinical trials.12,13 The use of diflunisal in patients with TTR cardiac amyloidosis is controversial given complication of chronic inhibition of cyclooxygenase (COX) enzymes, including gastrointestinal bleeding, renal dysfunction, fluid retention, and hypertension that may precipitate or exacerbate heart failure in vulnerable individuals.14-17 In TTR cardiac amyloidosis, an open-label cohort study suggested that low-dose diflunisal with careful monitoring along with a prophylactic proton pump inhibitor could be safely administered to compensated patients.18 An association was observed, however, between chronic diflunisal use and adverse changes in renal function suggesting that advanced kidney disease may be prohibitive in diflunisal therapy.In FAP patients with peripheral or autonomic neuropathy randomized to diflunisal or placebo, diflunisal slowed progression of neurologic impairment and preserved QOL over two years of follow-up.19 Echocardiography demonstrated cardiac involvement in approximately 50% of patients.20 Longer-term safety and efficacy data over an average 38 ± 31 months in 40 Japanese patients with hereditary ATTR amyloidosis who were not candidates for liver transplantation showed that diflunisal was mostly well tolerated.12 The authors cautioned the need for attentive monitoring of renal function and blood cell counts. Larger multicenter collaborations are needed to determine diflunisal’s true efficacy in HFPEF patients with TTR cardiac amyloidosis.

Tafamidis

Tafamidis is under active investigation as a novel compound that binds to the thyroxine-binding sites of the TTR tetramer, inhibiting its dissociation into monomers and blocking the rate-limiting step in the TTR amyloidogenesis cascade.21 The TTR compound was shown in an 18-month double-blind, placebo-controlled trial to slow progression of neurologic symptoms in patients with early-stage ATTRm due to the V30M mutation.22 When focusing on cardiomyopathy in a phase 2, open-label trial, tafamidis also appeared to effectively stabilize TTR tetramers in non-V30M variants, wild-type and V122I, as well as biochemical and echocardiographic parameters.23,24 Preliminary data suggests that clinically stabilized patients had shorter disease duration, lower cardiac biomarkers, less myocardial thickening, and higher EF than those who were not stabilized, suggesting early institution of therapy may be beneficial. A phase 3 trial has completed enrollment and will evaluate the efficacy, safety, and tolerability of tafamidis 20 or 80 mg orally vs. placebo.25 This will contribute to long-term safety and efficacy data needed to determine the therapeutic effects of tafamidis among ATTRm variants.

Amyloid Degraders (Doxycycline/TUDCA and Anti-SAP Antibodies)

Doxycycline/TUDCA

While silencer and stabilizer drugs are aimed at lowering amyloidogenic precursor protein production, they cannot remove already deposited fibrils in an infiltrated heart. Removal of already deposited fibrils by amyloid degraders would be an important therapeutic strategy, particularly in older adults with heavily infiltrated hearts reflected by thick walls, HFPEF, systolic heart failure, and restrictive cardiomyopathy. Combined doxycycline and tauroursodeoxycholic acid (TUDCA) disrupt TTR amyloid fibrils and appeared to have an acceptable safety profile in a small phase 2 open-label study among 20 TTR patients. No serious adverse reactions or clinical progression of cardiac or neuropathic involvement was observed over one year.26 An active phase 2, single-center, open-label, 12-month study will assess primary outcome measures including mBMI, neurologic impairment score, and NT-proBNP.27 Another phase 2 study is examining the tolerability and efficacy of doxycycline/TUDCA over an 18-month period in patients with TTR amyloid cardiomyopathy.28 Additionally, a study in patients with TTR amyloidosis is ongoing to determine the effect of doxycycline alone on neurologic function, cardiac biomarkers, echocardiographic parameters, modified body mass index, and autonomic neuropathy.29

Anti-SAP Antibodies

In order to safely clear established amyloid deposits, the role of the normal, nonfibrillar plasma glycoprotein present in all human amyloid deposits, serum amyloid P component (SAP), needs to be more clearly understood.30 In mice with amyloid AA type deposits, administration of antihuman SAP antibody triggered a potent giant cell reaction that removed massive visceral amyloid deposits without adverse effects.31 In humans with TTR cardiac amyloidosis, anti-SAP antibody treatments could be feasible because the bis-D proline compound, CPHPC, is capable of clearing circulating human SAP, which allow anti-SAP antibodies to reach residual deposited SAP. In a small, open-label, single-dose-escalation, phase 1 trial involving 15 patients with systemic amyloidosis, none of whom had clinical evidence of cardiac amyloidosis, were treated with CPHPC followed by human monoclonal IgG1 anti-SAP antibody.32 No serious adverse events were reported and amyloid deposits were cleared from the liver, kidney, and lymph node. Anti-SAP antibodies hold promise as a potential amyloid therapy because of their potential to target all forms of amyloid deposits across multiple tissue types.

Mutant or wild-type TTR cardiac amyloidoses are increasingly recognized as a cause of HFPEF. Clinicians need to be aware of this important HFPEF etiology because the diverse array of emerging disease-modifying agents for TTR cardiac amyloidosis in human clinical trials has the potential to herald a new era for the treatment of HFPEF.

References

  1. Maurer MS, Mancini D. HFpEF: is splitting into distinct phenotypes by comorbidities the pathway forward? J Am Coll Cardiol 2014;64:550-2.
  2. Mohammed SF, Mirzoyev SA, Edwards WD, et al. Left ventricular amyloid deposition in patients with heart failure and preserved ejection fraction. JACC Heart Fail 2014;2:113-22.
  3. González-López E, Gallego-Delgado M, Guzzo-Merello G, et al. Wild-type transthyretin amyloidosis as a cause of heart failure with preserved ejection fraction. Eur Heart J 2015.
  4. Castano A, Bokhari S, Maurer MS. Unveiling wild-type transthyretin cardiac amyloidosis as a significant and potentially modifiable cause of heart failure with preserved ejection fraction. Eur Heart J 2015 Jul 28. [Epub ahead of print]
  5. Rapezzi C, Merlini G, Quarta CC, et al. Systemic cardiac amyloidoses: disease profiles and clinical courses of the 3 main types. Circulation 2009;120:1203-12.
  6. Bokhari S, Castano A, Pozniakoff T, Deslisle S, Latif F, Maurer MS. (99m)Tc-pyrophosphate scintigraphy for differentiating light-chain cardiac amyloidosis from the transthyretin-related familial and senile cardiac amyloidoses. Circ Cardiovasc Imaging 2013;6:195-201.
  7. Fire A, Xu S, Montgomery MK, Kostas SA, Driver SE, Mello CC. Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans. Nature 1998;391:806-11.
  8. Elbashir SM, Harborth J, Lendeckel W, Yalcin A, Weber K, Tuschl T. Duplexes of 21-nucleotide RNAs mediate RNA interference in cultured mammalian cells. Nature 2001;411:494-8.
  9. Kanasty R, Dorkin JR, Vegas A, Anderson D. Delivery materials for siRNA therapeutics. Nature Mater 2013;12:967-77.
  10. U.S. National Institutes of Health. Phase 2 Study to Evaluate ALN-TTRSC in Patients With Transthyretin (TTR) Cardiac Amyloidosis (ClinicalTrials.gov website). 2014. Available at: https://www.clinicaltrials.gov/ct2/show/NCT01981837. Accessed 8/19/2015.
  11. U.S. National Institutes of Health. Efficacy and Safety of ISIS-TTRRx in Familial Amyloid Polyneuropathy (Clinical Trials.gov Website. 2013. Available at: http://www.clinicaltrials.gov/ct2/show/NCT01737398. Accessed 8/19/2015.
  12. Sekijima Y, Dendle MA, Kelly JW. Orally administered diflunisal stabilizes transthyretin against dissociation required for amyloidogenesis. Amyloid 2006;13:236-49.
  13. Tojo K, Sekijima Y, Kelly JW, Ikeda S. Diflunisal stabilizes familial amyloid polyneuropathy-associated transthyretin variant tetramers in serum against dissociation required for amyloidogenesis. Neurosci Res 2006;56:441-9.
  14. Epstein M. Non-steroidal anti-inflammatory drugs and the continuum of renal dysfunction. J Hypertens Suppl 2002;20:S17-23.
  15. Wallace JL. Pathogenesis of NSAID-induced gastroduodenal mucosal injury. Best Pract Res Clin Gastroenterol 2001;15:691-703.
  16. Mukherjee D, Nissen SE, Topol EJ. Risk of cardiovascular events associated with selective COX-2 inhibitors. JAMA 2001;286:954-9.
  17. Page J, Henry D. Consumption of NSAIDs and the development of congestive heart failure in elderly patients: an underrecognized public health problem. Arch Intern Med 2000;160:777-84.
  18. Castano A, Helmke S, Alvarez J, Delisle S, Maurer MS. Diflunisal for ATTR cardiac amyloidosis. Congest Heart Fail 2012;18:315-9.
  19. Berk JL, Suhr OB, Obici L, et al. Repurposing diflunisal for familial amyloid polyneuropathy: a randomized clinical trial. JAMA 2013;310:2658-67.
  20. Quarta CCF, Solomon RH Suhr SD, et al. The prevalence of cardiac amyloidosis in familial amyloidotic polyneuropathy with predominant neuropathy: The Diflunisal Trial. International Symposium on Amyloidosis 2014:88-9.
  21. Hammarstrom P, Jiang X, Hurshman AR, Powers ET, Kelly JW. Sequence-dependent denaturation energetics: A major determinant in amyloid disease diversity. Proc Natl Acad Sci U S A 2002;99 Suppl 4:16427-32.
  22. Coelho T, Maia LF, Martins da Silva A, et al. Tafamidis for transthyretin familial amyloid polyneuropathy: a randomized, controlled trial. Neurology 2012;79:785-92.
  23. Merlini G, Plante-Bordeneuve V, Judge DP, et al. Effects of tafamidis on transthyretin stabilization and clinical outcomes in patients with non-Val30Met transthyretin amyloidosis. J Cardiovasc Transl Res 2013;6:1011-20.
  24. Maurer MS, Grogan DR, Judge DP, et al. Tafamidis in transthyretin amyloid cardiomyopathy: effects on transthyretin stabilization and clinical outcomes. Circ Heart Fail 2015;8:519-26.
  25. U.S. National Institutes of Health. Safety and Efficacy of Tafamidis in Patients With Transthyretin Cardiomyopathy (ATTR-ACT) (ClinicalTrials.gov website). 2014. Available at: http://www.clinicaltrials.gov/show/NCT01994889. Accessed 8/19/2015.
  26. Obici L, Cortese A, Lozza A, et al. Doxycycline plus tauroursodeoxycholic acid for transthyretin amyloidosis: a phase II study. Amyloid 2012;19 Suppl 1:34-6.
  27. U.S. National Institutes of Health. Safety, Efficacy and Pharmacokinetics of Doxycycline Plus Tauroursodeoxycholic Acid in Transthyretin Amyloidosis (ClinicalTrials.gov website). 2011. Available at: http://www.clinicaltrials.gov/ct2/show/NCT01171859. Accessed 8/19/2015.
  28. U.S. National Institutes of Health. Tolerability and Efficacy of a Combination of Doxycycline and TUDCA in Patients With Transthyretin Amyloid Cardiomyopathy (ClinicalTrials.gov website). 2013. Available at: http://www.clinicaltrials.gov/ct2/show/NCT01855360. Accessed 8/19/2015.
  29. U.S. National Institutes of Health. Safety and Effect of Doxycycline in Patients With Amyloidosis (ClinicalTrials.gov website).2015. Available at: https://clinicaltrials.gov/ct2/show/NCT01677286. Accessed 8/19/2015.
  30. Pepys MB, Dash AC. Isolation of amyloid P component (protein AP) from normal serum as a calcium-dependent binding protein. Lancet 1977;1:1029-31.
  31. Bodin K, Ellmerich S, Kahan MC, et al. Antibodies to human serum amyloid P component eliminate visceral amyloid deposits. Nature 2010;468:93-7.
  32. Richards DB, Cookson LM, Berges AC, et al. Therapeutic Clearance of Amyloid by Antibodies to Serum Amyloid P Component. N Engl J Med 2015;373:1106-14.

 

The Acid-Mediated Denaturation Pathway of Transthyretin Yields a Conformational Intermediate That Can Self-Assemble into Amyloid

Zhihong Lai , Wilfredo Colón , and Jeffery W. Kelly *
Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255
Biochemistry199635 (20), pp 6470–6482   http://dx.doi.org:/10.1021/bi952501g
Publication Date (Web): May 21, 1996  Copyright © 1996 American Chemical Society

Transthyretin (TTR) amyloid fibril formation is observed during partial acid denaturation and while refolding acid-denatured TTR, implying that amyloid fibril formation results from the self-assembly of a conformational intermediate. The acid denaturation pathway of TTR has been studied in detail herein employing a variety of biophysical methods to characterize the intermediate(s) capable of amyloid fibril formation. At physiological concentrations, tetrameric TTR remains associated from pH 7 to pH 5 and is incapable of amyloid fibril formation. Tetrameric TTR dissociates to a monomer in a process that is dependent on both pH and protein concentration below pH 5. The extent of amyloid fibril formation correlates with the concentration of the TTR monomer having an altered, but defined, tertiary structure over the pH range of 5.0−3.9. The inherent Trp fluorescence-monitored denaturation curve of TTR exhibits a plateau over the pH range where amyloid fibril formation is observed (albeit at a higher concentration), implying that a steady-state concentration of the amyloidogenic intermediate with an altered tertiary structure is being detected. Interestingly, 1-anilino-8-naphthalenesulfonate fluorescence is at a minimum at the pH associated with maximal amyloid fibril formation (pH 4.4), implying that the amyloidogenic intermediate does not have a high extent of hydrophobic surface area exposed, consistent with a defined tertiary structure. Transthyretin has two Trp residues in its primary structure, Trp-41 and Trp-79, which are conveniently located far apart in the tertiary structure of TTR. Replacement of each Trp with Phe affords two single Trp containing variants which were used to probe local pH-dependent tertiary structural changes proximal to these chromophores. The pH-dependent fluorescence behavior of the Trp-79-Phe mutant strongly suggests that Trp-41 is located near the site of the tertiary structural rearrangement that occurs in the formation of the monomeric amyloidogenic intermediate, likely involving the C-strand−loop−D-strand region. Upon further acidification of TTR (below pH 4.4), the structurally defined monomeric amyloidogenic intermediate begins to adopt alternative conformations that are not amyloidogenic, ultimately forming an A-state conformation below pH 3 which is also not amyloidogenic. In summary, analytical equilibrium ultracentrifugation, SDS−PAGE, far- and near-UV CD, fluorescence, and light scattering studies suggest that the amyloidogenic intermediate is a monomeric predominantly β-sheet structure having a well-defined tertiary structure.

 

Prevention of Transthyretin Amyloid Disease by Changing Protein Misfolding Energetics

Per Hammarström*, R. Luke Wiseman*, Evan T. Powers, Jeffery W. Kelly   + Author Affiliations

Science  31 Jan 2003; 299(5607):713-716   http://dx.doi.org:/10.1126/science.1079589

Genetic evidence suggests that inhibition of amyloid fibril formation by small molecules should be effective against amyloid diseases. Known amyloid inhibitors appear to function by shifting the aggregation equilibrium away from the amyloid state. Here, we describe a series of transthyretin amyloidosis inhibitors that functioned by increasing the kinetic barrier associated with misfolding, preventing amyloidogenesis by stabilizing the native state. The trans-suppressor mutation, threonine 119 → methionine 119, which is known to ameliorate familial amyloid disease, also functioned through kinetic stabilization, implying that this small-molecule strategy should be effective in treating amyloid diseases.

 

Rational design of potent human transthyretin amyloid disease inhibitors

Thomas Klabunde1,2, H. Michael Petrassi3, Vibha B. Oza3, Prakash Raman3, Jeffery W. Kelly3 & James C. Sacchettini1

Nature Structural & Molecular Biology 2000; 7: 312 – 321.                http://dx.doi.org:/10.1038/74082

The human amyloid disorders, familial amyloid polyneuropathy, familial amyloid cardiomyopathy and senile systemic amyloidosis, are caused by insoluble transthyretin (TTR) fibrils, which deposit in the peripheral nerves and heart tissue. Several nonsteroidal anti-inflammatory drugs and structurally similar compounds have been found to strongly inhibit the formation of TTR amyloid fibrils in vitro. These include flufenamic acid, diclofenac, flurbiprofen, and resveratrol. Crystal structures of the protein–drug complexes have been determined to allow detailed analyses of the protein–drug interactions that stabilize the native tetrameric conformation of TTR and inhibit the formation of amyloidogenic TTR. Using a structure-based drug design approach ortho-trifluormethylphenyl anthranilic acid and N-(meta-trifluoromethylphenyl) phenoxazine 4,6-dicarboxylic acid have been discovered to be very potent and specific TTR fibril formation inhibitors. This research provides a rationale for a chemotherapeutic approach for the treatment of TTR-associated amyloid diseases.

 

First European consensus for diagnosis, management, and treatment of transthyretin familial amyloid polyneuropathy

Adams, Davida; Suhr, Ole B.b; Hund, Ernstc; Obici, Laurad; Tournev, Ivailoe,f; Campistol, Josep M.g; Slama, Michel S.h; Hazenberg, Bouke P.i; Coelho, Teresaj; from the European Network for TTR-FAP (ATTReuNET)

Current Opin Neurol: Feb 2016; 29 – Issue – p S14–S26      http://dx.doi.org:/10.1097/WCO.0000000000000289

Purpose of review: Early and accurate diagnosis of transthyretin familial amyloid polyneuropathy (TTR-FAP) represents one of the major challenges faced by physicians when caring for patients with idiopathic progressive neuropathy. There is little consensus in diagnostic and management approaches across Europe.

Recent findings: The low prevalence of TTR-FAP across Europe and the high variation in both genotype and phenotypic expression of the disease means that recognizing symptoms can be difficult outside of a specialized diagnostic environment. The resulting delay in diagnosis and the possibility of misdiagnosis can misguide clinical decision-making and negatively impact subsequent treatment approaches and outcomes.

Summary: This review summarizes the findings from two meetings of the European Network for TTR-FAP (ATTReuNET). This is an emerging group comprising representatives from 10 European countries with expertise in the diagnosis and management of TTR-FAP, including nine National Reference Centres. The current review presents management strategies and a consensus on the gold standard for diagnosis of TTR-FAP as well as a structured approach to ongoing multidisciplinary care for the patient. Greater communication, not just between members of an individual patient’s treatment team, but also between regional and national centres of expertise, is the key to the effective management of TTR-FAP.

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Transthyretin familial amyloid polyneuropathy (TTR-FAP) is a highly debilitating and irreversible neurological disorder presenting symptoms of progressive sensorimotor and autonomic neuropathy [1▪,2▪,3]. TTR-FAP is caused by misfolding of the transthyretin (TTR) protein leading to protein aggregation and the formation of amyloid fibrils and, ultimately, to amyloidosis (commonly in the peripheral and autonomic nervous system and the heart) [4,5]. TTR-FAP usually proves fatal within 7–12 years from the onset of symptoms, most often due to cardiac dysfunction, infection, or cachexia [6,7▪▪].

The prevalence and disease presentation of TTR-FAP vary widely within Europe. In endemic regions (northern Portugal, Sweden, Cyprus, and Majorca), patients tend to present with a distinct genotype in large concentrations, predominantly a Val30Met substitution in the TTR gene [8–10]. In other areas of Europe, the genetic footprint of TTR-FAP is more varied, with less typical phenotypic expression [6,11]. For these sporadic or scattered cases, a lack of awareness among physicians of variable clinical features and limited access to diagnostic tools (i.e., pathological studies and genetic screening) can contribute to high rates of misdiagnosis and poorer patient outcomes [1▪,11]. In general, early and late-onset variants of TTR-FAP, found within endemic and nonendemic regions, present several additional diagnostic challenges [11,12,13▪,14].

Delay in the time to diagnosis is a major obstacle to the optimal management of TTR-FAP. With the exception of those with a clearly diagnosed familial history of FAP, patients still invariably wait several years between the emergence of first clinical signs and accurate diagnosis [6,11,14]. The timely initiation of appropriate treatment is particularly pertinent, given the rapidity and irreversibility with which TTR-FAP can progress if left unchecked, as well as the limited effectiveness of available treatments during the later stages of the disease [14]. This review aims to consolidate the existing literature and present an update of the best practices in the management of TTR-FAP in Europe. A summary of the methods used to achieve a TTR-FAP diagnosis is presented, as well as a review of available treatments and recommendations for treatment according to disease status.

Patients with TTR-FAP can present with a range of symptoms [11], and care should be taken to acquire a thorough clinical history of the patient as well as a family history of genetic disease. Delay in diagnosis is most pronounced in areas where TTR-FAP is not endemic or when there is no positive family history [1▪]. TTR-FAP and TTR-familial amyloid cardiomyopathy (TTR-FAC) are the two prototypic clinical disease manifestations of a broader disease spectrum caused by an underlying hereditary ATTR amyloidosis [19]. In TTR-FAP, the disease manifestation of neuropathy is most prominent and definitive for diagnosis, whereas cardiomyopathy often suggests TTR-FAC. However, this distinction is often superficial because cardiomyopathy, autonomic neuropathy, vitreous opacities, kidney disease, and meningeal involvement all may be present with varying severity for each patient with TTR-FAP.

Among early onset TTR-FAP with usually positive family history, symptoms of polyneuropathy present early in the disease process and usually predominate throughout the progression of the disease, making neurological testing an important diagnostic aid [14]. Careful clinical examination (e.g., electromyography with nerve conduction studies and sympathetic skin response, quantitative sensation test, quantitative autonomic test) can be used to detect, characterize, and scale the severity of neuropathic abnormalities involving small and large nerve fibres [10]. Although a patient cannot be diagnosed definitively with TTR-FAP on the basis of clinical presentation alone, symptoms suggesting the early signs of peripheral neuropathy, autonomic dysfunction, and cardiac conduction disorders or infiltrative cardiomyopathy are all indicators that further TTR-FAP diagnostic investigation is warranted. Late-onset TTR-FAP often presents as sporadic cases with distinct clinical features (e.g., milder autonomic dysfunction) and can be more difficult to diagnose than early-onset TTR-FAP (Table 2) [1▪,11,12,13▪,14,20].

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Genetic testing is carried out to allow detection of specific amyloidogenic TTR mutations (Table 1), using varied techniques depending on the expertise and facilities available in each country (Table S2, http://links.lww.com/CONR/A39). A targeted approach to detect a specific mutation can be used for cases belonging to families with previous diagnosis. In index cases of either endemic and nonendemic regions that do not have a family history of disease, are difficult to confirm, and have atypical symptoms, TTR gene sequencing is required for the detection of both predicted and new amyloidogenic mutations [26,27].

Following diagnosis, the neuropathy stage and systemic extension of the disease should be determined in order to guide the next course of treatment (Table 4) [3,30,31]. The three stages of TTR-FAP severity are graded according to a patient’s walking disability and degree of assistance required [30]. Systemic assessment, especially of the heart, eyes, and kidney, is also essential to ensure all aspects of potential impact of the disease can be detected [10].

Table 4

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The goals of cardiac investigations are to detect serious conduction disorders with the risk of sudden death and infiltrative cardiomyopathy. Electrocardiograms (ECG), Holter-ECG, and intracardiac electrophysiology study are helpful to detect conduction disorders. Echocardiograms, cardiac magnetic resonance imaging, scintigraphy with bone tracers, and biomarkers (e.g., brain natriuretic peptide, troponin) can all help to diagnose infiltrative cardiomyopathy[10]. An early detection of cardiac abnormalities has obvious benefits to the patient, given that the prophylactic implantation of pacemakers was found to prevent 25% of major cardiac events in TTR-FAP patients followed up over an average of 4 years [32▪▪]. Assessment of cardiac denervation with 123-iodine meta-iodobenzylguanidine is a powerful prognostic marker in patients diagnosed with FAP [33].

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Tafamidis

Tafamidis is a first-in-class therapy that slows the progression of TTR amyloidogenesis by stabilizing the mutant TTR tetramer, thereby preventing its dissociation into monomers and amyloidogenic and toxic intermediates [55,56]. Tafamidis is currently indicated in Europe for the treatment of TTR amyloidosis in adult patients with stage I symptomatic polyneuropathy to delay peripheral neurological impairment [57].

In an 18-month, double-blind, placebo-controlled study of patients with early-onset Val30Met TTR-FAP, tafamidis was associated with a 52% lower reduction in neurological deterioration (P = 0.027), a preservation of nerve function, and TTR stabilization versus placebo [58▪▪]. However, only numerical differences were found for the coprimary endpoints of neuropathy impairment [neuropathy impairment score in the lower limb (NIS-LL) responder rates of 45.3% tafamidis vs 29.5% placebo; P = 0.068] and quality of life scores [58▪▪]. A 12-month, open-label extension study showed that the reduced rates of neurological deterioration associated with tafamidis were sustained over 30 months, with earlier initiation of tafamidis linking to better patient outcomes (P = 0.0435) [59▪]. The disease-slowing effects of tafamidis may be dependent on the early initiation of treatment. In an open-label study with Val30Met TTR-FAP patients with late-onset and advanced disease (NIS-LL score >10, mean age 56.4 years), NIS-LL and disability scores showed disease progression despite 12 months of treatment with tafamidis, marked by a worsening of neuropathy stage in 20% and the onset of orthostatic hypotension in 22% of patients at follow-up [60▪].

Tafamidis is not only effective in patients exhibiting the Val30Met mutation; it also has proven efficacy, in terms of TTR stabilization, in non-Val30Met patients over 12 months [61]. Although tafamidis has demonstrated safe use in patients with TTR-FAP, care should be exercised when prescribing to those with existing digestive problems (e.g., diarrhoea, faecal incontinence) [60▪].

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Diflunisal

Diflunisal is a nonsteroidal anti-inflammatory drug (NSAID) that, similar to tafamidis, slows the rate of amyloidogenesis by preventing the dissociation, misfolding, and misassembly of the mutated TTR tetramer [62,63]. Off-label use has been reported for patients with stage I and II disease, although diflunisal is not currently licensed for the treatment of TTR-FAP.

Evidence for the clinical effectiveness of diflunisal in TTR-FAP derives from a placebo-controlled, double-blind, 24-month study in 130 patients with clinically detectable peripheral or autonomic neuropathy[64▪]. The deterioration in NIS scores was significantly more pronounced in patients receiving placebo compared with those taking diflunisal (P = 0.001), and physical quality of life measures showed significant improvement among diflunisal-treated patients (P = 0.001). Notable during this study was the high rate of attrition in the placebo group, with 50% more placebo-treated patients dropping out of this 2-year study as a result of disease progression, advanced stage of the disease, and varied mutations.

One retrospective analysis of off-label use of diflunisal in patients with TTR-FAP reported treatment discontinuation in 57% of patients because of adverse events that were largely gastrointestinal [65]. Conclusions on the safety of diflunisal in TTR-FAP will depend on further investigations on the impact of known cardiovascular and renal side-effects associated with the NSAID drug class [66,67].

 

 

 

 

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Signaling through the T Cell Receptor (TCR) Complex and the Co-stimulatory Receptor CD28

Curator: Larry H. Bernstein, MD, FCAP

 

 

New connections: T cell actin dynamics

Fluorescence microscopy is one of the most important tools in cell biology research because it provides spatial and temporal information to investigate regulatory systems inside cells. This technique can generate data in the form of signal intensities at thousands of positions resolved inside individual live cells. However, given extensive cell-to-cell variation, these data cannot be readily assembled into three- or four-dimensional maps of protein concentration that can be compared across different cells and conditions. We have developed a method to enable comparison of imaging data from many cells and applied it to investigate actin dynamics in T cell activation. Antigen recognition in T cells by the T cell receptor (TCR) is amplified by engagement of the costimulatory receptor CD28. We imaged actin and eight core actin regulators to generate over a thousand movies of T cells under conditions in which CD28 was either engaged or blocked in the context of a strong TCR signal. Our computational analysis showed that the primary effect of costimulation blockade was to decrease recruitment of the activator of actin nucleation WAVE2 (Wiskott-Aldrich syndrome protein family verprolin-homologous protein 2) and the actin-severing protein cofilin to F-actin. Reconstitution of WAVE2 and cofilin activity restored the defect in actin signaling dynamics caused by costimulation blockade. Thus, we have developed and validated an approach to quantify protein distributions in time and space for the analysis of complex regulatory systems.

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Triple-Color FRET Analysis Reveals Conformational Changes in the WIP-WASp Actin-Regulating Complex

 

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T cell activation by antigens involves the formation of a complex, highly dynamic, yet organized signaling complex at the site of the T cell receptors (TCRs). Srikanth et al. found that the lymphocyte-specific large guanosine triphosphatase of the Rab family CRACR2A-a associated with vesicles near the Golgi in unstimulated mouse and human CD4+ T cells. Upon TCR activation, these vesicles moved to the immunological synapse (the contact region between a T cell and an antigen-presenting cell). The guanine nucleotide exchange factor Vav1 at the TCR complex recruited CRACR2A-a to the complex. Without CRACR2A-a, T cell activation was compromised because of defective calcium and kinase signaling.

More than 60 members of the Rab family of guanosine triphosphatases (GTPases) exist in the human genome. Rab GTPases are small proteins that are primarily involved in the formation, trafficking, and fusion of vesicles. We showed that CRACR2A (Ca2+ release–activated Ca2+ channel regulator 2A) encodes a lymphocyte-specific large Rab GTPase that contains multiple functional domains, including EF-hand motifs, a proline-rich domain (PRD), and a Rab GTPase domain with an unconventional prenylation site. Through experiments involving gene silencing in cells and knockout mice, we demonstrated a role for CRACR2A in the activation of the Ca2+ and c-Jun N-terminal kinase signaling pathways in response to T cell receptor (TCR) stimulation. Vesicles containing this Rab GTPase translocated from near the Golgi to the immunological synapse formed between a T cell and a cognate antigen-presenting cell to activate these signaling pathways. The interaction between the PRD of CRACR2A and the guanidine nucleotide exchange factor Vav1 was required for the accumulation of these vesicles at the immunological synapse. Furthermore, we demonstrated that GTP binding and prenylation of CRACR2A were associated with its localization near the Golgi and its stability. Our findings reveal a previously uncharacterized function of a large Rab GTPase and vesicles near the Golgi in TCR signaling. Other GTPases with similar domain architectures may have similar functions in T cells.

 

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