Archive for the ‘Microbiology’ Category

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


Food is digested by bathing in enzymes that break down its molecules. Those molecular fragments then pass through the gut wall and are absorbed in our intestines. But our bodies make a limited range of enzymes, so that we cannot break down many of the tough compounds in plants. The term “dietary fiber” refers to those indigestible molecules. These dietary fibers are indigestible only to us. The gut is coated with a layer of mucus, on which sits a carpet of hundreds of species of bacteria, part of the human microbiome. Some of these microbes carry the enzymes needed to break down various kinds of dietary fibers.


Scientists at the University of Gothenburg in Sweden are running experiments that are yielding some important new clues about fiber’s role in human health. Their research indicates that fiber doesn’t deliver many of its benefits directly to our bodies. Instead, the fiber we eat feeds billions of bacteria in our guts. Keeping them happy means our intestines and immune systems remain in good working order. The scientists have recently reported that the microbes are involved in the benefits obtained from the fruits-and-vegetables diet. Research proved that low fiber diet decreases the gut bacteria population by tenfold.


Along with changes to the microbiome there were also rapid changes observed in the experimental mice. Their intestines got smaller, and its mucus layer thinner. As a result, bacteria wound up much closer to the intestinal wall, and that encroachment triggered an immune reaction. After a few days on the low-fiber diet, mouse intestines developed chronic inflammation. After a few weeks, they started putting on fat and developing higher blood sugar levels. Inflammation can help fight infections, but if it becomes chronic, it can harm our bodies. Among other things, chronic inflammation may interfere with how the body uses the calories in food, storing more of it as fat rather than burning it for energy.


In a way fiber benefits human health is by giving, indirectly, another source of food. When bacteria finished harvesting the energy in the dietary fiber, they cast off the fragments as waste. That waste — in the form of short-chain fatty acids — is absorbed by intestinal cells, which use it as fuel. But the gut’s microbes do more than just make energy. They also send messages. Intestinal cells rely on chemical signals from the bacteria to work properly. The cells respond to the signals by multiplying and making a healthy supply of mucus. They also release bacteria-killing molecules. By generating these responses, gut bacteria help to maintain a peaceful coexistence with the immune system. They rest on the gut’s mucus layer at a safe distance from the intestinal wall. Any bacteria that wind up too close get wiped out by antimicrobial poisons.


A diet of fiber-rich foods, such as fruits and vegetables, reduces the risk of developing diabetes, heart disease and arthritis. Eating more fiber seems to lower people’s mortality rate, whatever be the cause. Researchers hope that they will learn more about how fiber influences the microbiome to use it as a way to treat disorders. Lowering inflammation with fiber may also help in the treatment of immune disorders such as inflammatory bowel disease. Fiber may also help reverse obesity. They found that fiber supplements helped obese people to lose weight. It’s possible that each type of fiber feeds a particular set of bacteria, which send their own important signals to our bodies.





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


Hepatitis B virus can cause serious, long-term health problems, such as liver disease and cancer, and can spread from mother-to-child during delivery. According to the latest estimates from the World Health Organization (WHO), approximately 257 million people in 2015 were living with the virus. Countries in Asia have a high burden of hepatitis B. There is no cure, and antiviral drugs used to treat the infection usually need to be taken for life.


To prevent infection, WHO recommends that all newborns receive their first dose of hepatitis B vaccine within 24 hours of delivery. Infants born to hepatitis B-infected mothers are also given protective antibodies called hepatitis B immune globulin (HBIG). However, mother-to-child transmission can still occur in women with high levels of virus in their blood, as well as those with mutated versions of the virus.


Tenofovir disoproxil fumarate (TDF), an antiviral drug commonly prescribed to treat hepatitis B infection, does not significantly reduce mother-to-child transmission of hepatitis B virus when taken during pregnancy and after delivery, according to a phase III clinical trial in Thailand funded by the National Institutes of Health. The study tested TDF therapy in addition to the standard preventative regimen — administration of hepatitis B vaccine and protective antibodies at birth — to explore the drug’s potential effects on mother-to-child transmission rates. The results appear in the New England Journal of Medicine.


The present study was conducted at 17 hospitals of the Ministry of Public Health in Thailand. It screened more than 2,500 women for eligibility and enrolled 331 pregnant women with hepatitis B. The women received placebo (163) or TDF (168) at intervals from 28 weeks of pregnancy to two months after delivery. All infants received standard hepatitis B preventatives given in Thailand, which include HBIG at birth and five doses of the hepatitis B vaccine by age 6 months (which differs from the three doses given in the United States). A total of 294 infants (147 in each group) were followed through age 6 months.


Three infants in the placebo group had hepatitis B infection at age 6 months, compared to zero infants in the TDF treatment group. Given the unexpectedly low transmission rate in the placebo group, the researchers concluded that the addition of TDF to current recommendations did not significantly reduce mother-to-child transmission of the virus.


According to the study, the clinical trial had enough participants to detect statistical differences if the transmission rate in the placebo group reached at least 12 percent, a rate observed in previous studies. Though the reasons are unknown, the researchers speculate that the lower transmission rate seen in the study may relate to the number of doses of hepatitis B vaccine given to infants in Thailand, lower rates of amniocentesis and Cesarean section deliveries in this study, or the lower prevalence of mutated viruses that result in higher vaccine efficacy in Thailand compared to other countries.




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


The trillions of microbes in the human gut are known to aid the body in synthesizing key vitamins and other nutrients. But this new study suggests that things can sometimes be more adversarial.


Choline is a key nutrient in a range of metabolic processes, as well as the production of cell membranes. Researchers identified a strain of choline-metabolizing E. coli that, when transplanted into the guts of germ-free mice, consumed enough of the nutrient to create a choline deficiency in them, even when the animals consumed a choline-rich diet.


This new study indicate that choline-utilizing bacteria compete with the host for this nutrient, significantly impacting plasma and hepatic levels of methyl-donor metabolites and recapitulating biochemical signatures of choline deficiency. Mice harboring high levels of choline-consuming bacteria showed increased susceptibility to metabolic disease in the context of a high-fat diet.


DNA methylation is essential for normal development and has been linked to everything from aging to carcinogenesis. This study showed changes in DNA methylation across multiple tissues, not just in adult mice with a choline-consuming gut microbiota, but also in the pups of those animals while they developed in utero.


Bacterially induced reduction of methyl-donor availability influenced global DNA methylation patterns in both adult mice and their offspring and engendered behavioral alterations. This study reveal an underappreciated effect of bacterial choline metabolism on host metabolism, epigenetics, and behavior.


The choline-deficient mice with choline-consuming gut microbes also showed much higher rates of infanticide, and exhibited signs of anxiety, with some mice over-grooming themselves and their cage-mates, sometimes to the point of baldness.


Tests have also shown as many as 65 percent of healthy individuals carry genes that encode for the enzyme that metabolizes choline in their gut microbiomes. This work suggests that interpersonal differences in microbial metabolism should be considered when determining optimal nutrient intake requirements.




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Medical Scientific Discoveries for the 21st Century & Interviews with Scientific Leaders at – electronic Table of Contents 

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

Available on Kindle Store @ 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,,,, 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,, 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,,,,, 6.5.4, 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


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


Chapter 1: Physicians as Authors


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


Chapter 2: Professional Recognition


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


Chapter 3:  Medical and Allied Health Sciences Education


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


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


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



Medical Scientific Discoveries Interviews with Scientific Leaders

Chapter 5: Cardiovascular System


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


Chapter 6: Genomics

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  @ 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 2014 Breakthrough Prizes Awarded in Fundamental Physics and Life Sciences for a Total of $21 Million – MIT’s Robert Langer gets $3 Million National Medal of Science – 2006 Robert S. Langer  Confluence of Chemistry, Physics, and Biology

6.5.2 JENNIFER DOUDNA Jennifer Doudna, cosmology teams named 2015 Breakthrough Prize winners UPDATED – Medical Interpretation of the Genomics Frontier – CRISPR – Cas9: Gene Editing Technology for New Therapeutics

6.5.3 ERIC LANDER  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


Chapter 7: The RNAs


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


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

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 


Chapter 9:  Neuroscience


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


Chapter 10: Microbiology & Immunology


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


Chapter 11: Endocrine Hormones


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


Chapter 12. Stem Cells


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

Chapter 13: 3D Printing and Medical Application


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


Chapter 14: Synthetic Medicinal Chemistry


14.1 Insights in Biological and Synthetic Medicinal Chemistry

14.2 Breakthrough work in cancer

Summary to Part Two

Volume Summary and Conclusions




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

During pregnancy, the baby is mostly protected from harmful microorganisms by the amniotic sac, but recent research suggests the baby could be exposed to small quantities of microbes from the placenta, amniotic fluid, umbilical cord blood and fetal membranes. One theory is that any possible prenatal exposure could ‘pre-seed’ the infant microbiome. In other words, to set the right conditions for the ‘main seeding event’ for founding the infant microbiome.

When a mother gives birth vaginally and if she breastfeeds, she passes on colonies of essential microbes to her baby. This continues a chain of maternal heritage that stretches through female ancestry for thousands of generations, if all have been vaginally born and breastfed. This means a child’s microbiome, that is the trillions of microorganisms that live on and in him or her, will resemble the microbiome of his/her mother, the grandmother, the great-grandmother and so on, if all have been vaginally born and breastfed.

As soon as the mother’s waters break, suddenly the baby is exposed to a wave of the mother’s vaginal microbes that wash over the baby in the birth canal. They coat the baby’s skin, and enter the baby’s eyes, ears, nose and some are swallowed to be sent down into the gut. More microbes form of the mother’s gut microbes join the colonization through contact with the mother’s faecal matter. Many more microbes come from every breath, from every touch including skin-to-skin contact with the mother and of course, from breastfeeding.

With formula feeding, the baby won’t receive the 700 species of microbes found in breast milk. Inside breast milk, there are special sugars called human milk oligosaccharides (HMO’s) that are indigestible by the baby. These sugars are designed to feed the mother’s microbes newly arrived in the baby’s gut. By multiplying quickly, the ‘good’ bacteria crowd out any potentially harmful pathogens. These ‘good’ bacteria help train the baby’s naive immune system, teaching it to identify what is to be tolerated and what is pathogen to be attacked. This leads to the optimal training of the infant immune system resulting in a child’s best possible lifelong health.

With C-section birth and formula feeding, the baby is not likely to acquire the full complement of the mother’s vaginal, gut and breast milk microbes. Therefore, the baby’s microbiome is not likely to closely resemble the mother’s microbiome. A baby born by C-section is likely to have a different microbiome from its mother, its grandmother, its great-grandmother and so on. C-section breaks the chain of maternal heritage and this break can never be restored.

The long term effect of an altered microbiome for a child’s lifelong health is still to be proven, but many studies link C-section with a significantly increased risk for developing asthma, Type 1 diabetes, celiac disease and obesity. Scientists might not yet have all the answers, but the picture that is forming is that C-section and formula feeding could be significantly impacting the health of the next generation. Through the transgenerational aspect to birth, it could even be impacting the health of future generations.


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Milestones in Physiology & Discoveries in Medicine and Genomics: Request for Book Review Writing on


Milestones in Physiology

Discoveries in Medicine, Genomics and Therapeutics

Patient-centric Perspective 




Author, Curator and Editor

Larry H Bernstein, MD, FCAP

Chief Scientific Officer

Leaders in Pharmaceutical Business Intelligence



Chapter 1: Evolution of the Foundation for Diagnostics and Pharmaceuticals Industries

1.1  Outline of Medical Discoveries between 1880 and 1980

1.2 The History of Infectious Diseases and Epidemiology in the late 19th and 20th Century

1.3 The Classification of Microbiota

1.4 Selected Contributions to Chemistry from 1880 to 1980

1.5 The Evolution of Clinical Chemistry in the 20th Century

1.6 Milestones in the Evolution of Diagnostics in the US HealthCare System: 1920s to Pre-Genomics


Chapter 2. The search for the evolution of function of proteins, enzymes and metal catalysts in life processes

2.1 The life and work of Allan Wilson
2.2  The  evolution of myoglobin and hemoglobin
2.3  More complexity in proteins evolution
2.4  Life on earth is traced to oxygen binding
2.5  The colors of life function
2.6  The colors of respiration and electron transport
2.7  Highlights of a green evolution


Chapter 3. Evolution of New Relationships in Neuroendocrine States
3.1 Pituitary endocrine axis
3.2 Thyroid function
3.3 Sex hormones
3.4 Adrenal Cortex
3.5 Pancreatic Islets
3.6 Parathyroids
3.7 Gastointestinal hormones
3.8 Endocrine action on midbrain
3.9 Neural activity regulating endocrine response

3.10 Genomic Promise for Neurodegenerative Diseases, Dementias, Autism Spectrum, Schizophrenia, and Serious Depression


Chapter 4.  Problems of the Circulation, Altitude, and Immunity

4.1 Innervation of Heart and Heart Rate
4.2 Action of hormones on the circulation
4.3 Allogeneic Transfusion Reactions
4.4 Graft-versus Host reaction
4.5 Unique problems of perinatal period
4.6. High altitude sickness
4.7 Deep water adaptation
4.8 Heart-Lung-and Kidney
4.9 Acute Lung Injury

4.10 Reconstruction of Life Processes requires both Genomics and Metabolomics to explain Phenotypes and Phylogenetics


Chapter 5. Problems of Diets and Lifestyle Changes

5.1 Anorexia nervosa
5.2 Voluntary and Involuntary S-insufficiency
5.3 Diarrheas – bacterial and nonbacterial
5.4 Gluten-free diets
5.5 Diet and cholesterol
5.6 Diet and Type 2 diabetes mellitus
5.7 Diet and exercise
5.8 Anxiety and quality of Life
5.9 Nutritional Supplements


Chapter 6. Advances in Genomics, Therapeutics and Pharmacogenomics

6.1 Natural Products Chemistry

6.2 The Challenge of Antimicrobial Resistance

6.3 Viruses, Vaccines and immunotherapy

6.4 Genomics and Metabolomics Advances in Cancer

6.5 Proteomics – Protein Interaction

6.6 Pharmacogenomics

6.7 Biomarker Guided Therapy

6.8 The Emergence of a Pharmaceutical Industry in the 20th Century: Diagnostics Industry and Drug Development in the Genomics Era: Mid 80s to Present

6.09 The Union of Biomarkers and Drug Development

6.10 Proteomics and Biomarker Discovery

6.11 Epigenomics and Companion Diagnostics


Chapter  7

Integration of Physiology, Genomics and Pharmacotherapy

7.1 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

7.2 Calcium Cycling (ATPase Pump) in Cardiac Gene Therapy: Inhalable Gene Therapy for Pulmonary Arterial Hypertension and Percutaneous Intra-coronary Artery Infusion for Heart Failure: Contributions by Roger J. Hajjar, MD

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

7.4 Synthetic Biology: On Advanced Genome Interpretation for Gene Variants and Pathways: What is the Genetic Base of Atherosclerosis and Loss of Arterial Elasticity with Aging

7.5 Diagnosing Diseases & Gene Therapy: Precision Genome Editing and Cost-effective microRNA Profiling

7.6 Imaging Biomarker for Arterial Stiffness: Pathways in Pharmacotherapy for Hypertension and Hypercholesterolemia Management

7.7 Neuroprotective Therapies: Pharmacogenomics vs Psychotropic drugs and Cholinesterase Inhibitors

7.8 Metabolite Identification Combining Genetic and Metabolic Information: Genetic association links unknown metabolites to functionally related genes

7.9 Preserved vs Reduced Ejection Fraction: Available and Needed Therapies

7.10 Biosimilars: Intellectual Property Creation and Protection by Pioneer and by

7.11 Demonstrate Biosimilarity: New FDA Biosimilar Guidelines


Chapter 7.  Biopharma Today

8.1 A Great University engaged in Drug Discovery: University of Pittsburgh

8.2 Introduction – The Evolution of Cancer Therapy and Cancer Research: How We Got Here?

8.3 Predicting Tumor Response, Progression, and Time to Recurrence

8.4 Targeting Untargetable Proto-Oncogenes

8.5 Innovation: Drug Discovery, Medical Devices and Digital Health

8.6 Cardiotoxicity and Cardiomyopathy Related to Drugs Adverse Effects

8.7 Nanotechnology and Ocular Drug Delivery: Part I

8.8 Transdermal drug delivery (TDD) system and nanotechnology: Part II

8.9 The Delicate Connection: IDO (Indolamine 2, 3 dehydrogenase) and Cancer Immunology

8.10 Natural Drug Target Discovery and Translational Medicine in Human Microbiome

8.11 From Genomics of Microorganisms to Translational Medicine

8.12 Confined Indolamine 2, 3 dioxygenase (IDO) Controls the Homeostasis of Immune Responses for Good and Bad


Chapter 9. BioPharma – Future Trends

9.1 Artificial Intelligence Versus the Scientist: Who Will Win?

9.2 The Vibrant Philly Biotech Scene: Focus on KannaLife Sciences and the Discipline and Potential of Pharmacognosy

9.3 The Vibrant Philly Biotech Scene: Focus on Computer-Aided Drug Design and Gfree Bio, LLC

9.4 Heroes in Medical Research: The Postdoctoral Fellow

9.5 NIH Considers Guidelines for CAR-T therapy: Report from Recombinant DNA Advisory Committee

9.6 1st Pitch Life Science- Philadelphia- What VCs Really Think of your Pitch

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

9.8 Heroes in Medical Research: Green Fluorescent Protein and the Rough Road in Science

9.9 Issues in Personalized Medicine in Cancer: Intratumor Heterogeneity and Branched Evolution Revealed by Multiregion Sequencing

9.10 The SCID Pig II: Researchers Develop Another SCID Pig, And Another Great Model For Cancer Research


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Phosphorylation-dependent interaction between antigenic peptides and MHC class I

Curator: Larry H. Bernstein, MD, FCAP



Phosphorylation-dependent interaction between antigenic peptides and MHC class I: a molecular basis for the presentation of transformed self.

Nat Immunol. 2008 Nov;9(11):1236-43.  Epub 2008 Oct 5.
Protein phosphorylation generates a source of phosphopeptides that are presented by major histocompatibility complex class I molecules and recognized by T cells. As deregulated phosphorylation is a hallmark of malignant transformation, the differential display of phosphopeptides on cancer cells provides an immunological signature of ‘transformed self’. Here we demonstrate that phosphorylation can considerably increase peptide binding affinity for HLA-A2. To understand this, we solved crystal structures of four phosphopeptide-HLA-A2 complexes. These identified a novel peptide-binding motif centered on a solvent-exposed phosphate anchor. Our findings indicate that deregulated phosphorylation can create neoantigens by promoting binding to major histocompatibility complex molecules or by affecting the antigenic identity of presented epitopes. These results highlight the potential of phosphopeptides as novel targets for cancer immunotherapy.
Figure 1
Bioinformatic characterization of the HLA-A2–restricted phosphopeptide repertoire. (a) Distribution of phosphorylated residues among naturally processed (A2 phosphopeptide) and predicted HLA-A2 binding phosphopeptides (Phosphosite, EMBL). The frequency of phosphorylated residues at each position is displayed for naturally processed HLA-A2 associated phosphopeptides, and for peptides in EMBL and Phosphosite datasets that contain phosphorylation sites and are predicted, according to criteria described in Methods, to bind HLA-A2. (b) Representation of positively charged residues (Arg or Lys) at P1 among naturally processed HLA-A2 associated phosphopeptides, phosphopeptides from the EMBL or Phosphosite datasets that are predicted to bind HLA-A2 and contain a p-Ser residue at the P4 position, and datasets of naturally processed non-phosphorylated peptides (B-LCL) and known HLA-A2 binding peptides (Immune Epitope). Selection criteria for the latter two datasets are described in Methods. * = P<0.001, NS= not significant. (c, d) Representation of subdominant residues at the P2 anchor position (c) and the PC (P9) position (d) in naturally processed HLA-A2 associated phosphopeptides and in datasets of naturally processed non-phosphorylated peptides and known HLA-A2 binding peptides.
Changes in protein expression or metabolism due to intracellular infection or cellular transformation modify the repertoire of peptides generated and therefore displayed by class I MHC molecules, resulting in presentation of “altered self” to the immune system. T cell receptor (TCR)-mediated recognition of specific MHC-bound peptides by CD8 T lymphocytes results in cytolytic activity and release of pro-inflammatory cytokines, which are key components of anti-viral and anti-tumor immunity. Evidence suggests that peptides containing post-translational modifications (PTM), including deamidation, cysteinylation, glycosylation, and phosphorylation, contribute to the pool of MHC-bound peptides presented at the cell surface and represent potential targets for T cell recognition2. Indeed, the majority of naturally occurring PTM-bearing peptides defined to date can be discriminated from their unmodified homologs specifically by T cells2-4.  …..
Recent studies have highlighted protein phosphorylation as a process with the capacity to generate unique peptides bound to class I MHC molecules. Significant numbers of different phosphorylated peptides are presented by several HLA-A and HLA-B alleles that are prevalent in humans3,4, demonstrating their widespread potential as antigens. Moreover, CD8+ T lymphocytes recognize these phosphopeptides in a manner that is both peptide sequence-specific and phosphate-dependent3, 4. Thus, phosphopeptides can be immunologically distinguished from their non-phosphorylated counterparts. Consistent with their presentation by class I MHC molecules, most phosphorylated peptides are derived from proteins that function intracellularly, and processing of both model and naturally occurring phosphopeptides is dependent on transport into the endoplasmic reticulum (ER) by transporter associated with antigen processing (TAP)3, 5. Furthermore, rapid degradation by the proteasome, a process that regulates the activity of many transcription factors, cell growth modulators, signal transducers and cell cycle proteins6-8, is frequently dependent on target protein phosphorylation9-11. ….
Phosphopeptide antigens are of significant therapeutic interest because deregulation of protein kinase activity, normally tightly controlled, is one of the hallmarks of malignant transformation and is thought to contribute directly to oncogenic signaling pathways involved in cell growth, differentiation and survival13-15. In addition, mutation-induced deregulation of a limited number of critical kinases can often lead to activation of several signaling cascades and increases in the extent of protein phosphorylation within the cell16-18. These considerations strongly suggest that alterations in protein phosphorylation during malignancy represent a distinctive immunological signature of “transformed self”. Consistent with this notion, the phosphopeptides presented by HLA-A*0201….

Nα-Terminal Acetylation for T Cell Recognition: Molecular Basis of MHC Class I–Restricted Nα-Acetylpeptide Presentation

As one of the most common posttranslational modifications (PTMs) of eukaryotic proteins, Nα-terminal acetylation (Nt-acetylation) generates a class of Nα-acetylpeptides that are known to be presented by MHC class I at the cell surface. Although such PTM plays a pivotal role in adjusting proteolysis, the molecular basis for the presentation and T cell recognition of Nα-acetylpeptides remains largely unknown. In this study, we determined a high-resolution crystallographic structure of HLA (HLA)-B*3901 complexed with an Nα-acetylpeptide derived from natural cellular processing, also in comparison with the unmodified-peptide complex. Unlike the α-amino–free P1 residues of unmodified peptide, of which the α-amino group inserts into pocket A of the Ag-binding groove, the Nα-linked acetyl of the acetylated P1-Ser protrudes out of the groove for T cell recognition. Moreover, the Nt-acetylation not only alters the conformation of the peptide but also switches the residues in the α1-helix of HLA-B*3901, which may impact the T cell engagement. The thermostability measurements of complexes between Nα-acetylpeptides and a series of MHC class I molecules derived from different species reveal reduced stability. Our findings provide the insight into the mode of Nα-acetylpeptide–specific presentation by classical MHC class I molecules and shed light on the potential of acetylepitope-based immune intervene and vaccine development.

Produced by Ag processing and proteasomal degradation of intracellular proteins, polypeptides serve as CTL epitopes presented by MHC class I molecules, which play a critical role in cellular immunity (1). Eukaryotic proteins bearing various posttranslational modifications (PTMs) can generate a group of modified Ags, which contribute to a special repertoire of MHC-associated peptides presented at the cell surface as potential targets for TCR-mediated recognition. A modified peptide may become a new Ag because of the distinguished antigenicity compared with its unmodified homolog. A variety of natural peptide Ags containing modification have been observed that can be immunologically discriminated by T cells from their unmodified homologs as “altered self” (2). Thus, the significance of PTMs on epitopes and the application of modified peptides in vaccine development for immunotherapy against cancer and autoimmune diseases have been increasingly appreciated (3, 4).

The molecular bases of the presentation of peptides with several PTMs by MHC class I molecules have been successfully explicated. For instance, the formyl group on an Nt-formylated peptide binds to the bottom of the peptide-binding groove of H2-M3 (5); both the glycan and the phosphate moieties of the central region of the glycopeptides (6, 7) and the phosphopeptides (8, 9), respectively, are exposed to enable TCR binding, and the deimination (citrullination) of arginine on a peptide presented by two HLA-B27 subtypes induces distinct peptide conformations (10).

Nα-terminal acetylation (Nt-acetylation) is one of the most common PTMs, occurring on the vast majority of eukaryotic proteins. In humans, >80% of the different varieties of intracellular proteins are irreversibly Nt-acetylated by Nα-acetyltransferases, often after the removal of the initiator methionine. Only a subset of the penultimate residues (Ala, Ser, Thr, Cys, and Val) or the retained initiator methionine can be acetylated at the α-amino (NH2) groups (11). A recent study found that acetylated N-terminal residues of eukaryotic proteins act as specific degradation signals (Ac-N-degrons) that are recognized by specific ubiquitin ligases (12). A subsequent systematic analysis demonstrated that Nt-acetylation can also represent an early determining factor in the cellular sorting for prevention of protein targeting to the secretory pathway (13). These findings suggested that Nt-acetylation–mediated inhibition of secretion could contribute to the retention of proteins in the cytosol where they may subsequently be ubiquitinylated through the specific recognition of their Ac-N-degrons and thereby generating Nt-acetylated proteasomal digestion products (14). Hence, these Nt-acetylated polypeptides in the form of MHC-associated neoantigens stand a good chance to be recognized by T cells. This has indeed been illuminated in an Nt-acetylated MHC class II–restricted peptide derived from myelin basic protein, which stimulates murine T cells to elicit experimental autoimmune encephalomyelitis, whereas the nonacetylated form does not (15). A structural study subsequently suggested that the Nt-acetylation of this peptide is essential for MHC class II binding (16).

For MHC class I, the first Nt-acetylated natural ligand was identified more than a decade ago (17). However, the mode of interaction of this acetylated peptide with class I molecules remained largely enigmatic. To understand this, we determined the crystal structures of a naturally occurring Nt-acetylated self-peptide (NAc-SL9) and two nonmodified variants (SL9 and HL8), respectively, in complex with HLA-B*3901. Taken together with the thermostability analyses of Nα-acetylpeptides complexed with a series of class I molecules of human and murine origin, we elucidated that Nt-acetylation exerts a destabilizing effect on peptide–MHC (pMHC) complex, thereby influencing TCR recognition.


Our results here provide the structural and thermodynamic insights into the presentation of Nt-acetylated peptides by MHC class I molecules. The structure of the Nα-acetylpeptide in complex with HLA-B*3901 outlines a molecular interpretation of the reduced stability of MHC class I–bound Nt-acetylated peptides and also highlights a potential influence of Nt-acetylation on antigenic identity and T cell recognition. In addition, the structure elucidation of HLA-B*3901, the predominant B39 subtype, also is valuable in studying immune diseases associated with this MHC allele.

In a previous report, the Nt-formyl group on an Nt-formylated peptide binds to the bottom of the peptide-binding groove of the murine MHC class I H2-M3 playing an anchoring role for MHC class I binding (Supplemental Fig. 2A) (5). In our study, the methyl and carbonyl groups of the acetyl are rotated upwards like two arms that push the peptide-binding groove open (Fig. 2G, Supplemental Fig. 2B), thereby altering its immunogenicity at the expense of the pMHC stability. The thermostability we tested from seven human and one murine complexes indicates a general feature of Nα-acetylpeptide in weakening the binding affinity to MHC class I, which could be revealed by the gel-filtration chromatography of pMHC refolding assays as well (Supplemental Fig. 3). Their instability would partially explain why, as yet, such epitopes are rarely found. Within N-terminal residues of eukaryotic proteins, Ser is the most frequently acetylated in vivo (11). The Ala, Thr, Cys, and Val residues can also be Nt-acetylated and have small side chains like Ser. Thus, the rotation of P1 residues observed in the pHLA-B*3901 complex with an acetylated P1-Ser could very well be a general mode in Nα-acetylpeptide binding. In contrast, the long side chain of Met precludes it from being rotated into pocket A, but a certain reorientation is presumed to take place in the acetylated P1-Met based on the thermal instability (Fig. 6H). Besides the accommodation of the acetyl moiety, Nt-acetylation is presumed to decrease the stability of the pHLA-B*3901 complex as a result of the conformational switch of the Arg62. Arg62 in the α1-helix is largely conserved in almost all HLA-B and -C allotypes (Table V). For other HLA class I (Table V, Fig. 8), the long charged side chains of the residues in position 62 (Glu62 of A24 and Gln62 of A11 and so on) also may interact with the acetyl. Hence, the residue in position 62 plays a key role in the interaction between acetyl group and the H chain, which may influence not only the Nα-acetylpeptide binding to HLA molecules but also the TCR docking.

The discoveries that intracellular proteins with Ac-N-degrons are inhibited from being secreted (13) and then are degraded via ubiquitylation (12) raise many questions on the biological significance of acetylation-mediated proteolysis (14). The Nt-acetylated peptides with the size of MHC class I ligands (8–11 aa) as neoepitopes for CD8+ T cells, represent one of the possible roles of the Nt-acetylated digestion products. The vast armory of intracellular proteins that are frequently Nt-acetylated can create a large pool of Nα-acetylpeptides for Ag presentation and T cell surveying. The Nt-acetylation potentially impacts the TCR-MHC interaction in three different aspects: 1) the direct interaction of the solvent-exposed acetyl moiety; 2) the altered conformation of the central region of the peptide main chain; and 3) the conformational switches of the MHC residues. The Nt-acetylation creation of a distinctive pMHC landscape and participation in a potential binding element for TCR engagement described in our results highlights needs for further investigation into the Nα-acetylpeptide–specific TCR repertoires.  ……

see…J Immunol 2014; 192:5509-5519



The Cellular Redox Environment Alters Antigen Presentation*

Jonathan A. Trujillo,§12Nathan P. Croft,1Nadine L. Dudek,1Rudragouda ChannappanavarAlex TheodossisAndrew I. Webb,…., Jamie Rossjohn,‡‡,§§5Stanley Perlman,§6 and Anthony W. Purcell,7
The Journal of Biological Chemistry 289; 27979-27991.


Background: Modification of cysteine residues, including glutathionylation, commonly occurs in peptides bound to and presented by MHC molecules.

Results: Glutathionylation of a coronavirus-specific T cell epitope results in diminished CD8 T cell recognition.

Conclusion: Cysteine modification of a T cell epitope negatively impacts the host immune response.

Significance: Cross-talk between virus-induced oxidative stress and the T cell response probably occurs, diminishing host cell recognition of infected cells.

Cysteine-containing peptides represent an important class of T cell epitopes, yet their prevalence remains underestimated. We have established and interrogated a database of around 70,000 naturally processed MHC-bound peptides and demonstrate that cysteine-containing peptides are presented on the surface of cells in an MHC allomorph-dependent manner and comprise on average 5–10% of the immunopeptidome. A significant proportion of these peptides are oxidatively modified, most commonly through covalent linkage with the antioxidant glutathione. Unlike some of the previously reported cysteine-based modifications, this represents a true physiological alteration of cysteine residues. Furthermore, our results suggest that alterations in the cellular redox state induced by viral infection are communicated to the immune system through the presentation of S-glutathionylated viral peptides, resulting in altered T cell recognition. Our data provide a structural basis for how the glutathione modification alters recognition by virus-specific T cells. Collectively, these results suggest that oxidative stress represents a mechanism for modulating the virus-specific T cell response.

Antigen Presentation     Antigen Processing     Glutathionylation     Mass Spectrometry (MS)     Oxidation-Reduction (Redox)     Redox Regulation     T-cell     Viral Immunology

Small fragments of proteins (peptides) derived from both intracellular and extracellular sources are displayed on the surface of cells by molecules encoded within the major histocompatibility complex (MHC). These peptides are recognized by T lymphocytes and provide the immune system with a surveillance mechanism for the detection of pathogens and cancer cells. The fidelity with which antigen presentation communicates changes in the intracellular proteome is critical for immune surveillance. Not only do antigens expressed at vastly different abundances need to be represented within the array of peptides selected and presented at the cell surface (collectively termed the immunopeptidome (1, 2)), but changes in their post-translational state also need to be conveyed within this complex mixture of peptides. For example, changes in antigen phosphorylation have been linked to cancer, and the presentation of phosphorylated peptides has been shown to communicate the cancerous state of cells to the immune system (36). Other types of post-translational modification play a central role in the pathogenesis of autoimmune diseases (7), such as arginine citrullination in arthritis (810), deamidation of glutamine residues in wheat proteins in celiac disease (1115), and cysteine oxidation in type 1 diabetes (16, 17). Cysteine is predicted to be present in up to 14% of potential T cell epitopes based on its prevalence in various pathogen and host proteomes (18). However, reports of cysteine-containing epitopes are much less frequent due to technical difficulties associated with synthesis and handling of cysteine-containing peptides and their subsequent avoidance in many epitope mapping studies (19). Cysteine can be modified in numerous ways, including cysteinylation (the disulfide linkage of free cysteine to peptide or protein cysteine residues), oxidation to cysteine sulfenic (oxidation), sulfinic (dioxidation) and sulfonic acids (trioxidation), S-nitrosylation, and S-glutathionylation. Such modifications may occur prior to or during antigen processing; however, the role of cysteine modification in T-cell-mediated immunity has not been systematically addressed.

In addition to constitutive presentation of a subset of oxidatively modified peptides, it is anticipated that changes in the proportion of these ligands will occur upon infection because oxidative stress, triggering of the unfolded protein response, and modulation of host cell synthesis by the virus are hallmarks of this process (2027). For example, host cell stress responses modulate expression, localization, and function of Toll-like receptors, a key event in the initiation of the immune response (28). Oxidative stress would also be predicted to affect protein function through post-translational modification of amino acids, such as cysteine. Indeed, because of the reactive nature of cysteine and the requirements for cells to regulate the redox state of proteins to maintain function, a number of scavenging systems for redox-reactive intermediates exist. The tripeptide glutathione (GSH) is one of the key intracellular antioxidants, acting as a scavenger for reactive oxygen species. Reduced GSH is equilibrated with its oxidized form, GSSG, with normal cytosolic conditions being that of the reduced state in a ratio of ∼50:1 (GSH/GSSG) (29). Modification of proteins and peptides with GSH (termed S-glutathionylation) occurs following reaction of GSSG with the thiol group of cysteine in a reaction catalyzed by the detoxifying enzyme, glutathione S-transferase (GST). A variety of cellular processes and signaling pathways, such as the induction of innate immunity, apoptosis, redox homeostasis, and cytokine production, are modulated by this GST-catalyzed post-translational modification (3032). S-Glutathionylation can eventuate via oxidative stress, whereby the intracellular levels of GSSG increase.

Given that viruses are known to induce oxidative stress (3335), the intracellular environment of viral infection may lead to an increase inS-glutathionylated cellular proteins and viral antigens. For instance, HSV infection induces an early burst of reactive oxygen species, resulting in S-glutathionylation of TRAF family members, which in turn is linked to downstream signaling and interferon production (36). The potential for modification of viral antigens subsequent to reactive oxygen species production is highlighted by S-glutathionylation of several retroviral proteases, leading to host modulation of protease function (37). Indeed large scale changes in protein S-glutathionylation are observed in HIV-infected T cell blasts (38), suggesting that functional modulation of both host and viral proteins occurs via this mechanism. Whether these S-glutathionylated proteins inhibit or enhance immune responses to the unmodified epitope or generate novel T-cell epitopes that are subsequently recognized by the adaptive immune system is unclear.

Here, we investigate the frequency of modification of cysteine-containing MHC-bound peptides by interrogating a large database of naturally processed self-peptides derived from B-lymphoblastoid cells, murine tissues, and cytokine-treated cells. In addition, the functional consequences of Cys modification of T cell epitopes was investigated using an established model of infection that involves an immunodominant cysteine-containing epitope derived from a neurotropic strain of mouse hepatitis virus, strain JHM (JHMV)8(3941). We describe S-glutathionylation of this viral T cell epitope and the functional and structural implications of redox-modulated antigen presentation. Collectively our studies suggest that S-glutathionylation plays a key, previously unappreciated role in adaptive immune recognition.



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