Four New Targets For Breast Cancer Identified By Researchers

Four suspects often found at the scene of the crime in cancer are guilty of the initiation and progression of breast cancer in mice that are resistant to the disease, a team led by scientists at The University of Texas M. D. Anderson Cancer Center reports in the June edition of Cancer Cell.



"We have a smoking gun" that shows it's no coincidence the three protein receptors and the enzyme that makes them are abnormally expressed in many types of cancer, said Gordon Mills, M.D., Ph.D., professor and chair of M. D. Anderson's Department of Systems Biology and senior author of the paper.



"We've compiled lots of evidence that they are associated with cancer, what's been missing is proof that they could cause cancer," Mills said. "There are no questions left, they should be targeted."



The four are three lysophosphatidic acid (LPA) receptors (LPA1, LPA2, and LPA3) and the LPA-producing enzyme, autotaxin. "Lysophosphatidic acid", Mills said, "is the single most potent known cellular survival factor." LPA binds to a series of G protein-coupled receptors to spark normal cell proliferation, viability, production of growth factors and survival. The Cancer Cell paper shows this powerful network is hijacked to initiate breast cancer and fuel tumor growth, invasion and metastasis.



The team took a strain of mice that is highly resistant to breast cancer and then created four transgenic strains, each strain expressing one of the receptors or autotaxin.



At 24 months, none of the 44 original cancer-resistant mice developed mammary gland cancer. Only one case of inflammation and two cases of a potentially precancerous accumulation of cells known as hyperplasia were noted.



Cancer incidence ranged from 32 percent to 52.8 percent in the four strains of mice with one of the culprit receptors or autotaxin. Invasive and/or metastatic tumors were present to varying degrees, with 45.5 percent of the tumors in the LPA3 strain metastasizing.



A number of drugs are in preclinical development that target the receptors and autotaxin, Mills said. "Now we have transgenic mouse models to test drugs to go forward against these targets."



The four transgenic strains of mice have three unusual characteristics that the team believes make them particularly well-suited as a model of human breast cancer. Unlike most other mouse models, these produce breast cancer that is invasive and metastatic, and some tumors that are estrogen-receptor positive. ER-positive disease is the most common type of breast cancer.



The research was funded by grants from the National Cancer Institute, the U.S. Department of Defense Breast Cancer Research Program, the Breast Cancer Research Foundation, the M. D. Anderson NCI core grant, and sponsored research by LPATH Biotechnologies.



Co-authors are first author Shuying Liu, M.D., Ph.D., Makiko Umezu-Goto, Ph.D., Mandi Murph, Ph.D., Yiling Lu, M.D., Fan Zhang, M.S. and Shuangxing Yu, M.D., all of M. D. Anderson's Department of Systems Biology; Wenbin Liu, Ph.D. and Kevin Coombes, Ph.D., of the Department of Bioinformatics and Computational Biology; L. Clifton Stephens, Ph.D., D.V.M, of the Department of Veterinary Medicine and Surgery; and Mien-Chie Hung, Ph.D., Department of Molecular and Cellular Oncology; Adrian Lee, Ph.D., and Xiaojiang Cui, Ph.D., of the Lester and Sue Smith Breast Center at the Baylor College of Medicine, Cui is now with John Wayne Cancer Institute of Saint John's Health Center in Santa Monica, CA ; George Murrow and Charles Perou, Ph.D., of the Lineberger Comprehensive Cancer Center, University of North Carolina; William Muller, Ph.D., of McGill Cancer Centre in Montreal; and Xianjun Fang, Ph.D., of the Department of Biochemistry and Molecular Biology at Virginia Commonwealth University.



Source:
Scott Merville


University of Texas M. D. Anderson Cancer Center

Award Lectures For ASBMB's 2007 Annual Meeting

The 2007 annual meeting of the American Society for Biochemistry and Molecular Biology (ASBMB) will feature the latest news about cell biology, signaling pathways, and genome dynamics, with 156 presentations in over 50 sessions. The meeting will also include award lectures and sessions on educational and professional development, minority affairs studies, and the interplay between the biomedical sciences and public policy. The meeting will take place at the Washington Convention Center, 801 Mt. Vernon Place, NW, Washington, D.C., from April 28 to May 2.



The ASBMB meeting is part of a multi-society meeting called Experimental Biology 2007 (EB 2007), which also includes the annual meetings of the American Association of Anatomists, the American Physiological Society, the American Society for Investigative Pathology, the American Society for Nutrition, and the American Society for Pharmacology and Experimental Therapeutics.



Brief descriptions of the Award Lectures follow. The times indicated below may vary depending on the time taken by preceding presentations.



SATURDAY, APRIL 28



ASBMB Opening Lecture and Herbert Tabor/Journal of Biological Chemistry Lectureship
6:05 p.m.-6:50 p.m., Ballroom C


"Tyrosine Phosphorylation: From Discovery to the Kinome and Beyond"


TONY HUNTER, American Cancer Society Professor of Molecular and Cell Biology at the Salk Institute for Biological Studies, La Jolla, Calif., will discuss the latest results on studies of the human kinome - a catalogue of genes that express key cellular proteins called protein kinases. Mutations in these genes have been found to cause various diseases, including cancer, which explains the current high interest in this topic.



ASBMB Opening Lecture and Herbert Tabor/Journal of Biological Chemistry Lectureship
6:50 p.m.-7:30 p.m., Ballroom C


"Phosphotyrosine Signaling: A Prototype for Modular Protein-Protein Interactions"


TONY PAWSON, Senior Investigator at the Samuel Lunenfeld Research Institute of Mount Sinai Hospital in Toronto, Canada, will discuss how proteins "talk" to each other. He will argue that such protein interactions allow biological functions to evolve and that when these interactions go awry, they can cause diseases.



SUNDAY, APRIL 29



Avanti Award in Lipids - 8:30 a.m.-9:30 a.m., Ballroom C


"Phosphoinositide Lipid Signaling in the Regulation of Membrane Trafficking and Organelle Identity"
SCOTT D. EMR, Investigator with the Howard Hughes Medical Institute and Professor of Cellular and Molecular Medicine in the School of Medicine at the University of California, San Diego, will present recent research on phosphoinositide lipids, which are molecules in cell membranes that regulate cell growth; the transport of molecules between or within cells; and the arrangement of the cell's cytoskeleton, a network of fibers throughout the cell's cytoplasm that helps the cell maintain its shape and gives it support.
















ASBMB Award for Exemplary Contributions to Education - 12:30 p.m.-1:30 p.m., Room 201
"The Importance of Research in the Undergraduate Curriculum: Explorations in Genomics"
SARAH C. ELGIN, Professor of Biology, Genetics and Education at Washington University, St. Louis, Mo., will explain how students and scientists are working together on a research project that annotates and analyzes fruit fly chromosomes. Future projects will take advantage of the increasing amount of data on genomes, large and small, now available in public databases.



ASBMB-Merck Award - 2:15 p.m.-3:15 p.m., Ballroom C


"Quinoproteins and Cofactors: Expecting the Unexpected"


JUDITH P. KLINMAN, Professor of Chemistry at the University of California, Berkeley, will describe a new family of proteins called quino-enzymes. Most enzymes can interact with each other through small molecules called coenzymes that attach to the enzymes' surfaces, but quino-enzymes display coenzymes inside their structure. Klinman will describe some of the unexpected features of these quino-enzymes.



MONDAY, APRIL 30



Fritz Lipmann Lectureship - 8:30 a.m.-9:30 a.m., Ballroom C


"PPARs: Running Around Obesity"


RONALD M. EVANS, Professor of Biology at the Salk Institute for Biological Studies, San Diego, Calif. will present the latest findings on the potential anti-obesity effects of a receptor located on cell nuclei called peroxisome proliferator-activated receptor delta (PPAR-delta). The receptor is already known to regulate inflammation, suggesting it may be an effective drug against heart disease. Evans and his team have shown that PPAR-delta helps the liver resume its normal function in obese mice. Evans will discuss how PPAR-delta activation in muscle can dramatically enhance running endurance, producing a strain of marathon mice.



TUESDAY, MAY 1



Schering-Plough Research Institute Award - 8:30 a.m.-9:30 a.m., Ballroom C


"Towards an RNA Splicing Code"


CHRISTOPHER B. BURGE, Associate Professor of Biology at MIT, will discuss the latest results on how a messenger RNA is modified - by removing its non-coding portions - before being used to produce proteins. He will present some of the key players (proteins and RNA) that induce these changes and how they interact with each other.



Howard K. Schachman Public Service Award - 12:30 p.m.-1:30 p.m., Room 201


"Public Policy and Biomedical Research"


MARY WOOLLEY, President and CEO of Research!America, the nation's largest not-for-profit public education and advocacy alliance, will comment on the current public and political climate for medical research and discuss why and how researchers can become more involved in making research a much higher national priority.



ASBMB - Amgen Award - 2:15 p.m.-3:15 p.m., Ballroom C


"Causes and Consequences of Aneuploidy"


ANGELIKA AMON, Associate Professor of Biology at MIT, will present the latest research on what can go wrong during cell division and the consequences thereof. When cell division goes wrong, cells can either become cancerous or end up with an abnormal number of chromosomes - a condition called aneuploidy and involved in causing cancer. Amon will describe her work on how cells become aneuploid and how her findings may provide new hints into the genetic origins of cancer.



WEDNESDAY, MAY 2



William C. Rose Award - 8:30 a.m.-9:30 a.m., Ballroom C


"Dynamics of Signaling by Protein Kinase A"


SUSAN S. TAYLOR, Professor of Chemistry and Biochemistry at the University of California, San Diego, will describe new findings on the structure of protein kinase A, a key enzyme that has several functions in mammalian cell, including regulation of glucose and lipid metabolism. She will explain the dynamic changes that are necessary to allow protein kinase A to become active. These changes have relevance for all members of the protein kinase superfamily.







Contact: Pat Pages


American Society for Biochemistry and Molecular Biology

New Test To Detect Rare Proteins In Blood

Researchers at the University of Pennsylvania School of Medicine have developed a paradigm-shifting method for detecting small amounts of proteins in the blood. Applications of this method will make discerning low-abundance molecules associated with cancers (such as breast cancer), Alzheimer's disease, prion diseases, and possibly psychiatric diseases relatively easy and more accurate compared with the current methodology, including the widely used ELISA (enzyme-linked immunoadsorbent assay).


ELISA is a common immune-system-based assay that uses enzymes linked to an antibody or antigen as a marker for picking out specific proteins. For example, it is used as a diagnostic test to determine exposure to infectious agents, such as HIV, by identifying antibodies present in a blood sample.


The sensitivity of detecting molecules by the new method, called FACTT, short for Florescent Amplification Catalyzed by T7-polymerase Technique, is five orders of magnitude (100,000 times) greater than that of ELISA, the Penn researchers found.


Senior author Mark I. Greene MD, PhD, the John Eckman Professor of Medical Science, Hongtao Zhang, PhD research specialist; Xin Cheng, PhD, research investigator, and Mark Richter, a research technician in Greene's lab, report their findings in the advanced online publication of Nature Medicine.


"The current ELISA tests can only detect proteins when they are in high abundance," says Zhang. "But the problem is that many of the functional proteins - those that have a role in determining your health - exist in very low amounts until diseases are apparent and cannot be detected or measured at early stages of medical pathology. It was important to develop a technique that can detect these rare molecules to detect abnormalities at an early stage."


The FACTT technology uses a different enzyme amplification system so quantitative signals can be obtained from even a few protein molecules compared to ELISA. "The technology is remarkably adaptable to any protein and can be performed in an automated format," notes Greene. He states that the technology will soon be robotized so as to be able to screen for many rare disease-causing proteins using tiny amounts of blood. "It is even possible that one could screen for multiple diseases at the same time and produce a precise accounting of whether disease-causing molecules are present at an early time when disease can be readily treated," adds Greene.


Greene also noted that the FACTT technology represents the further evolution of an earlier approach that was developed in collaboration with Professor of Pharmacology James Eberwine, PhD, also from Penn. The earlier technique employed radioisotopes.















Development of a test for the cancer marker Her2/neu


The researchers compared detection of Her2/neu in the blood between ELISA and FACTT. Her2/neu proteins were in fact first identified by the Greene laboratory in the early 1980s, and the Her2/neu gene was found by other scientists to be overexpressed in breast cancer. Her2/neu is normally a low-abundance molecule that becomes overexpressed in more than 30 percent of primary breast, ovarian, and pancreatic tumors. Part of the Her2/neu molecule is shed from the surface of tumor cells and has been detected in the blood of breast-cancer patients. Higher blood concentrations of Her2/neu correlate with a lower response rate to chemotherapy and shorter survival time after relapse.


The Greene lab developed mouse models that carry cancer cells overexpressing Her2/neu. When these cells are implanted into animals they form tumors exactly like breast tumors in humans. Using ELISA, the researchers could not detect Her2/neu from mouse blood until the tumors reached an inoperable size, but with the new FACTT technology they could detect Her2/Neu in some mice when tumors were barely visible and within two days of implantation. These results indicate that it is possible to detect tumors at very early stages so that tumor emergence or reoccurrence can be rapidly treated or even prevented.


Greene's laboratory established many of the principles of targeted therapy for Her2/neu tumors and the prototype antibodies that led to the development of Herceptin, a similar antibody molecule that was created by Genentech. The Greene laboratory also previously showed that early treatment of Her2/neu tumors with targeted monoclonal antibodies in animal models led to far more significant prevention of tumor growth as well as tumor emergence and reoccurrence.


Greene stresses that early treatment is far more effective than treating advanced tumors with the same antibodies. Recent clinical trials support the notion that early treatment prevents tumor reoccurrence in women with breast tumors. FACTT technology represents a way to couple early diagnosis with early treatment to prevent tumor emergence.


Detecting Her2/neu in humans for breast cancer


The most widely used clinical Her2/neu tests are IHC (immunohistochemistry) and FISH (fluorescence in situ hybridization). However, both FISH and IHC are complex, time-consuming tests.


Patients who test positive for Her2/neu using FISH or IHC have responsive rates of about 35 percent to the cancer drug Herceptin. Monitoring Her2/neu status from the blood with a powerful technology such as FACTT represents an alternative approach compared to IHC or FISH, say the researchers.


Pre-treatment Her2/neu levels correlate with tumor size and the extent of disease. Post-treatment Her2/neu levels predict disease-specific survival. A more sensitive assay could more accurately allow treatment of humans with breast cancer and allow treatment more quickly if the tumor reoccurs.


The researchers collected blood samples from healthy women and breast cancer patients who did or did not overexpress Her2/neu, as detected by IHC and FISH. When using the new FACTT method her2/neu positive cancer patients showed dramatically elevated Her2/neu levels (average: 384 ng/ml), while the level in Her2/neu-negative breast cancer patients (19.5 ng/ml) were close to the levels of the healthy control participants (16.6 ng/ml).


Using FACTT, nine out of 10 of the Her2/neu positive patients had elevated Her2/neu levels and one out of four in the Her2/neu negative group had elevated Her2/neu levels. Using ELISA only two out of 10 in the Her2/neu positive group showed elevated Her2/neu levels.


"Clearly the sensitivity of the ELISA assay does not satisfy the current need for the clinical detection of marker proteins that determine whether a patient has breast cancer or not," says Greene.


The researchers have also tried the FACTT method on other rare, but medically important molecules, such as the prion protein (for mad cow disease with Mansun Sy at Case Western University) and TNF-alpha (for autoimmune diseases), and will be developing tests for other cancer markers including lung cancer and colon cancer. All proteins tested so far with FACTT have been detected with an over 1000-fold higher sensitivity compared to current technologies.


The researchers say this points to FACTT's broad applicability and compatibility with current high-throughput testing technology. This, in turn, will facilitate the detection of rare markers and not-so-rare targets from much smaller sample volumes, as well as aid in monitoring marker levels at much earlier stages of disease.


"The importance of FACTT is that we can still get an accurate description of the number of molecules that cause disease even when other assays cannot," says Greene. The researchers surmise that FACTT could be used to monitor levels of Her2/neu in already-diagnosed breast cancer patients to monitor recurrence or treatment effectiveness.


"The critical issue arises when women are diagnosed with early breast cancer," adds Greene. "They often have a lumpectomy and are sometimes treated with radiation or chemotherapy, but despite this conventional therapy the cancer still can occasionally reoccur," says Greene. Detection of very early recurrence is important and Greene feels the power of this technology will facilitate recognizing early phases of tumor emergence.


Rational targeted therapy has shown in animal models - over 10 years ago - and more recently in clinical trials that treatment of small or incipient tumors is a way to prevent tumor emergence or reoccurrence. "Prevention of the consequences of recurrence is critical since treating advanced tumors is very complex and difficult," concludes Greene.


This research was funded in part by The Abramson Family Cancer Research Institute. This release can also be seen at: uphs.upenn/news.


The Abramson Cancer Center of the University of Pennsylvania was established in 1973 as a center of excellence in cancer research, patient care, education and outreach. Today, the Abramson Cancer Center ranks as one of the nation's best in cancer care, according to U.S. News & World Report, and is one of the top five in National Cancer Institute (NCI) funding. It is one of only 39 NCI-designated comprehensive cancer centers in the United States. Home to one of the largest clinical and research programs in the world, the Abramson Cancer Center of the University of Pennsylvania has 275 active cancer researchers and 250 Penn physicians involved in cancer prevention, diagnosis and treatment.


PENN Medicine is a $2.7 billion enterprise dedicated to the related missions of medical education, biomedical research, and high-quality patient care. PENN Medicine consists of the University of Pennsylvania School of Medicine (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System.


Penn's School of Medicine is ranked #2 in the nation for receipt of NIH research funds; and ranked #4 in the nation in U.S. News & World Report's most recent ranking of top research-oriented medical schools. Supporting 1,400 fulltime faculty and 700 students, the School of Medicine is recognized worldwide for its superior education and training of the next generation of physician-scientists and leaders of academic medicine.


Penn Health System comprises: its flagship hospital, the Hospital of the University of Pennsylvania, consistently rated one of the nation's "Honor Roll" hospitals by U.S. News & World Report; Pennsylvania Hospital, the nation's first hospital; Presbyterian Medical Center; a faculty practice plan; a primary-care provider network; two multispecialty satellite facilities; and home health care and hospice.


University of Pennsylvania School of Medicine

3600 Market Street, Suite 240

Philadelphia, PA 19104

United States
med.upenn


View drug information on Herceptin.

Protein Critical For Insulin Secretion May Be Contributor To Diabetes

A cellular protein from a family involved in several human diseases is crucial for the proper production and release of insulin, new research has found, suggesting that the protein might play a role in diabetes.



Mice lacking the ClC-3 channel, a passageway that allows negatively-charged chloride ions to pass through cell membranes, have only one-fifth the circulating insulin of normal mice, according to research published this month in the journal Cell Metabolism.



Researchers Deborah Nelson and Louis Philipson of the University of Chicago, senior authors on the paper, argue that the finding may explain a portion of what goes wrong in Type 2 diabetes and could help doctors find rare patients whose diabetes has a previously-undetected genetic origin.



"Chloride regulation is not really well understood, but it's at the heart of cystic fibrosis, and it is related to the regulation of how insulin gets made," said Philipson, professor of medicine and medical director of the Kovler Diabetes Center at the University of Chicago. "Now we see that it's a critical feature of how insulin gets converted from a precursor form to its most active form."



Insulin is made and released by specialized pancreas cells called Beta-cells. The cell first synthesizes a protein called pro-insulin, discovered forty years ago at the University of Chicago by Donald Steiner, which is then put inside structures called secretory granules.



Inside the secretory granule, proinsulin is chemically converted into insulin, and the granule moves to the cell surface where it can release insulin into the blood. Steiner discovered that the conversion of proinsulin to insulin must happen in an acidic environment, but how the granules make themselves acidic was unknown.



A team lead by Ludmila Deriy, a research assistant professor in Nelson's laboratory, studied genetic knockout mice missing the ClC-3 chloride channel. The blood of those mice contained lower levels of insulin and cellular measurements discovered that fewer granules were released by Beta-cells from ClC-3 knockouts and that the granules of ClC-3 knockout mice were less acidic than those from normal mice.



High-powered electron microscope images allowed researchers to observe that the granules of ClC-3 knockout mice contained higher amounts of proinsulin than granules from normal mice. Missing ClC-3 therefore appears to cause a dramatic slowdown of the conversion of proinsulin to insulin inside the granules, said Nelson, professor of neurobiology at the University of Chicago.



"Not only is release down, but what is released is not as efficacious a molecule," Nelson said. "It's pro-insulin rather insulin, if anything's released at all."



A mutation in the function of ClC-3 in humans could very well be the cause of a select few cases of juvenile diabetes, Nelson and Philipson said. However, while other ClC proteins have been linked to bone, muscle and kidney disease, no human case of diabetes has yet been linked to the function of this specific protein. Because ClC-3 knockout mice also experience epileptic seizures, a patient diagnosed with both epilepsy and diabetes could potentially have an undetected defect in their ClC-3 channel.
















"If it happens that there's epilepsy and diabetes, it's not currently recognized as a syndrome," Philipson said. "We would be extremely interested in cases like that."



Finding a patient with this rare form of genetically-caused diabetes could be aided by efforts such as Lilly's Law, an Illinois legislation signed in August that created a statewide diabetes registry. The law requires that doctors report all diagnoses of children younger than 12 months to the state Department of Public Health. Scientists can then test those children to see if their disease is caused by a genetic mutation, knowledge that can improve the child's treatment.



The law is named for Lilly Jaffe, a girl diagnosed with Type 1 diabetes that was treated by Philipson and University of Chicago Medical Center colleagues in 2006. Lilly was found to have a rare genetic mutation in a different cellular protein, meaning her disease was treatable with oral medication rather than insulin injections.



A mutation of the ClC-3 channel would probably still be treated with insulin rather than an oral medication. But observing ClC-3 function in humans may provide insight into Type 2 diabetes as well, Philipson said, as the disruption of insulin production and secretion resembles cellular effects seen in adult-onset diabetes.



"We know that Type 2 diabetes is a progressive illness where insulin secretion is high and then goes down over time, but why does it do that? This ties some connection between chloride channels and granular function to the ability of insulin to come out of the cell," Philipson said. "This could be an important pathway in Type 2 diabetes, so it's not just the rare patient that's affected, it's 25 million people in the United States."



The study, "The Granular Chloride Channel ClC-3 Is Permissive for Insulin Secretion," was published in the journal Cell Metabolism on October 7. Alongside Deriy, Philipson, and Nelson, Erwin Gomez, David Jacobson, XueQing Wang, Jessika Hopson, Xiang Liu, Guangping Zhang, and Vytautas Bindokas are listed as authors. All authors come from the University of Chicago.



Funding for the research was provided by the National Institutes of Health and by the University of Chicago Diabetes Research and Training Center.



Source:
Rob Mitchum


University of Chicago Medical Center

Proteomics Yields New Drug Targets For Treating Cardiogenic Shock

When it comes to cell signaling and bioregulation, it's tough to find a more important molecule than nitric oxide (NO). Dysfunction of NO-mediated signaling is thought to be a culprit in lethal cardiovascular conditions such as angina, and septic, cardiogenic and hemorrhagic shock; it may play a role in many other illnesses as well.



NO is a very unusual cell signaling molecule in that its actions result from chemical bonds made with proteins, rather than simple lock-and-key binding. A predominant reaction of NO with proteins is addition to sulfur in the amino acid cysteine -- a process called "S-nitrosylation."



But because these S-NO bonds are so fragile -- it's been notoriously difficult to spot exactly where, among the thousands of cellular proteins, NO is reacting and having its effects. A comprehensive way of identifying protein S-nitrosylation sites should greatly improve our understanding of how NO acts and hasten new drug discovery.



That "comprehensive way" is now here.



Reporting recently in the Proceedings of the National Academy of Sciences, scientists at the Weill Medical College of Cornell University, New York City, say they've devised the first-ever method of combing through the body's tens of thousands of proteins to inventory sites of S-nitrosylation.


"It's a real breakthrough for both basic science and drug research -- a tool that should significantly accelerate our understanding of nitric oxide signaling," says senior researcher Dr. Steven S. Gross, Professor of Pharmacology at Weill Cornell Medical College.



About 18 years ago, scientists made the remarkable discovery that NO is a product of mammalian cells and not merely an environmental toxin.



"It was surprising because nitric oxide is a reactive 'free radical' molecule -- the kind that's usually thought of as harmful or toxic," Dr. Gross said. "But it turns out that nature has invented a way to use it for physiological signaling via its chemistry with proteins. And this signaling can have broad and important downstream effects -- things like fighting infections, communicating between nerve cells, determining the diameter of blood vessels and the force of a heart's contraction."



In fact, one of the first heart drugs, nitroglycerin, substitutes for nitric oxide to trigger vasodilation (widening of blood vessels), although just how it does so is incompletely understood.



"That's why a better means of spotting S-nitrosylation sites is so important. It will help us better understand how many existing drugs work, and point the way to new targets for drug development," explains study lead author Gang Hao, a postdoctoral researcher in Dr. Gross' lab.



But the instability of the S-NO bond has, in the past, posed a problem for researchers. "You can know that this signaling is going on in tissues, but once you try to define the exact molecular sites, the ease of NO rearrangement can leave you guessing as to which protein sites are real," Dr. Gross says.
















The new technique, called SNO Site IDentification (SNOSID), quickly screens the proteome -- the body's thousands of gene-expressed proteins -- to find S-nitrosylation sites. The method relies on state-of-the-art mass spectrometry for sequencing amino acids from hundreds of peptides in protein digests obtained from cells and organs.


SNOSID builds on a technology called "biotin-switch," originally described by Dr. Samie Jaffrey while a postdoc in the lab of Solomon Snyder at Johns Hopkins. (Dr. Jaffrey has since become Assistant Professor of Pharmacology at Weill Cornell.)



Dr. Gross explains: "We know that we can't capture the S-nitrosylated bond itself, but this method uses a kind of surrogate, biotin, to stably replace NO at sites of S-nitrosylation. So the site of biotinylation in a protein becomes a kind of chemical flag showing us where NO used to be and providing us with a chemical strategy to enrich these sites for analysis."



According to the researchers, SNOSID should speed research toward a fuller understanding of the role of NO signaling in healthy cellular functions.



"It should also point the way to protein sites that could be important drug targets in the fight against disease," Hao says.


Phase III Clinical Trial Underway



Dr. Gross and other Weill Cornell scientists anticipate the benefits of new drugs that inhibit NO synthesis. Already, a Phase III clinical trial, based on Weill Cornell technology, is testing whether such a drug can save the lives of patients with cardiogenic shock, an emergency condition that kills more than half of its victims and occurs in 8 to 10 percent of patients with severe heart attacks.



"It's thought that cardiogenic-shock patients suffer from an excess of NO," Dr. Gross explains. "The ongoing study is blinded, so results are not yet available. But there's real hope the drug will be proven to save lives. If so, it would likely become the new standard-of-care for patients stricken by this highly lethal condition."



"This is really only the tip of the iceberg," Dr. Gross adds. "As SNOSID uncovers new and important sites of protein S-nitrosylation, novel drug targets are likely to be revealed. It should open the door to fertile new areas of research."



The study was supported by a grant from the National Institutes of Health.



Co-researchers included Dr. Lei Shi, Dr. Fabien Campagne, and Behrad Derakhshan -- all of the Weill Medical College of Cornell University, New York City.


Joan and Sanford I. Weill Medical College of Cornell University

525 East 68th Street, Box 144

New York, NY 10021

nyp

Improving Understanding Of Parkinson's Disease With The Help Of Yeast

Teams of scientists from Australia and the United States have used yeast and mammalian cells to discover a connection between genetic and environmental causes of Parkinson's disease.



Yeasts are single cell organisms, used widely in biological research because their structure resembles that of cells found in animals and humans. Yeasts share many genes, or their functional equivalents, with humans and offer the ability to screen or test thousands of genes and analysing their effects.



Two genes (alpha-synuclein and PARK9) had separately been associated with forms of Parkinson's disease, while manganese poisoning can cause PD-like symptoms in miners and welders exposed to high manganese levels. Findings connecting alpha-synuclein, PARK9 and sensitivity to manganese, made possible by yeast research, have been published online in the February issue of the prestigious international journal, Nature Genetics.



"This is the first time that we've been able to connect three pieces of the Parkinson's disease jigsaw puzzle and it tells us we're on the right track to understanding what goes wrong in this disease" said Dr Antony Cooper from Sydney's Garvan Institute of Medical Research and head of the project group in Australia.



Parkinson's disease involves the degeneration of neurons that produce the neurotransmitter dopamine. Autopsies show an abundance of the small protein alpha-synuclein in affected regions of the brain, so scientists have known for some time that over-expression of the protein is toxic.



When a European group discovered PARK9's involvement in an inherited form of Parkinson's disease they examined some of the surviving neurons from patients who had 'sporadic' Parkinson's, as opposed to inherited forms of the disease, and found they contained ten times the levels of PARK9 when compared with similar parts of the brain in patients without the disease.



"Its possible that the surviving neurons remained functional, unlike the degenerated neurons surrounding them, because high levels of PARK9 protected them in some way," said Cooper.



"Little was known of PARK9's function but as yeast contains an equivalent gene, we were able to analyse its function."



"We found that high levels of the PARK9 in a cell diminish the toxic effects of alpha-synuclein. We also found that it appears to be a manganese pump, capable in theory of removing excess levels of the metal from cells."



"We need to know what is happening at the critical early stages of the disease, so that we can stop it, but we only get to examine human brains after death, when the damage has been done. Using yeast allows us to examine the early damaging stages."



A key, and perplexing, question for researchers in the field has been whether or not there is a single cause, or related group of genetic determinants, that result in dopaminergic neuron loss, or 'Parkinson's disease'.
















"We would love to be able to link all the genes that we know have something to do with Parkinson's disease," said Cooper. "If you discover there's a central pathway involved, it provides much better potential for finding a successful treatment"



"So far, we've linked PARK9, alpha-synuclein and manganese toxicity. These linkages are not coincidental. They're likely to be affecting a pathway and we suspect it's a central pathway. To confirm that would be very exciting indeed."



Dr Cooper has been collaborating for several years with Dr Susan Lindquist, from the Whitehead Institute for Biomedical Research and Dr Aaron Gitler, from the University of Pennsylvania School of Medicine, to find how alpha-synuclein can damage cells.



To confirm that their results were not specific to yeast alone, Gitler, Cooper and Lindquist collaborated with Associate Professor Guy Caldwell, from the University of Alabama, and Associate Professor Jean-Christophe Rochet from the University of Purdue in Indiana, who verified their results in other Parkinson model systems.



"We wanted to check our findings were relevant in other Parkinson's models, because the more models it fits into, the more you believe it's real," said Cooper.



Notes:



ABOUT GARVAN



The Garvan Institute of Medical Research was founded in 1963. Initially a research department of St Vincent's Hospital in Sydney, it is now one of Australia's largest medical research institutions with nearly 500 scientists, students and support staff. Garvan's main research programs are: Cancer, Diabetes & Obesity, Immunology and Inflammation, Osteoporosis and Bone Biology, and Neuroscience. The Garvan's mission is to make significant contributions to medical science that will change the directions of science and medicine and have major impacts on human health. The outcome of Garvan's discoveries is the development of better methods of diagnosis, treatment, and ultimately, prevention of disease.



Source: Alison Heather


Research Australia

Are Sex-Biased Genes More Dispensible?

Females and males of many animals look very different, and most of these differences are due to different expression levels of the same genes.



So-called sex-biased genes have several peculiar evolutionary properties suggesting they are less important to survival than other genes, and in this opinion we lay out the evidence to support this hypothesis.



Further testing will be needed to confirm whether sex-biased genes are more dispensable, but if the notion is true, it will be important in understanding how and why males and females differ from each other.



Journal of the Royal Society Interface


Journal of the Royal Society Interface is the Society's cross-disciplinary publication promoting research at the interface between the physical and life sciences. It offers rapidity, visibility and high-quality peer review and is ranked fifth in JCR's multidisciplinary category. The journal also incorporates Interface Focus, a peer-reviewed, themed supplement, each issue of which concentrates on a specific cross-disciplinary subject.


Journal of the Royal Society Interface

Cause For Severe Pediatric Epilepsy Disorder Identified

Researchers at the University of California, San Diego School of Medicine have discovered that convulsive seizures in a form of severe epilepsy are generated, not on the brain's surface as expected, but from within the memory-forming hippocampus. The scientists hope that their findings - based on a mouse model of severe epilepsy - may someday pave the way for improved treatments of childhood epilepsy, which affects more than two percent of children worldwide. Their study will be published online by the Proceedings of the National Academy of Science (PNAS) the week of March 16.



"A parent of an epileptic child will tell you that they think their child is going to die during their attacks," said senior author Joseph Gleeson, MD, director of the Neurogenetics Laboratory at the UC San Diego School of Medicine, professor in the department of neurosciences and Howard Hughes Medical Institute Investigator. "Parents of children with epilepsy, especially the most severe types of epilepsy, are desperate for a deeper understanding of the causes of the problems and for the development of new treatments."



One of the major causes of epilepsy in children is an alteration in the development of the cerebral cortex. The cerebral cortex is the main folded part of the brain, containing a large percentage of brain cells, and is integral to purposeful actions and thoughts. However, this complex structure is subject to all kinds of defects in development, many of them due to defective genes and many associated with epilepsy.



Cortical dysplasia, meaning disordered development of the cerebral cortex, is identified in 25 to 40 percent of children with the most severe and difficult-to-treat forms of epilepsy. These children often come to the attention of specialists due to stagnation in the acquisition of language and balance skills and accompanying epilepsy. The symptoms displayed by these children can range from very subtle - such as small muscle jerks or eyelid fluttering - to dramatic whole body, tonic-clonic spasms (a series of contractions and relaxations of the muscle) that can affect basic bodily function.



The Gleeson team, led by researchers Geraldine Kerjan, PhD and Hiroyuki Koizumi, PhD, has been studying a disorder called "lissencephaly." (In Greek, leios means smooth, and kephale means brain or head.) Children with lissencephaly have a smooth brain surface that lacks the normal hills and valleys that are characteristic of the human brain. The researchers were recently successful in developing a mouse model that showed some of the features of this disorder, usually the first step toward understanding the cause of a genetic disorder. But the severe epilepsy that is associated with lissencephaly was never displayed in any of the previous animals, so the team kept removing gene after gene until they hit upon a strain that showed epilepsy.



"We study the gene "doublecortin," which is defective in some forms of epilepsy and mental retardation in humans," said Kerjan, lead author of the study. "However, only after we removed a combination of two of the genes in the doublecortin family did we uncover epilepsy."



According to Gleeson, the findings were dramatic, as almost none of the mice in this strain survived to adulthood. Thinking that the deaths might be due to epilepsy, the scientists recorded electroencephalograms, which measure electrical activity produced by the firing of neurons in the brain, and found severe epilepsy in all of the mice tested. Even more surprising was the site of the epileptic focus - or site from which the seizures were generated - which was located beneath the surface of the brain, in the hippocampus.



"Researchers had thought that the cause of the seizures in this disease must be the brain surface, since this is the part that looks the most abnormal on brain MRI scans," said Gleeson. "However, we found that the epilepsy focus was actually deeper in the brain, within the hippocampus, the main memory-forming site."



The research team intends to continue studying in studying the mice, to explore potential mechanisms and utilize this model to test new treatments.



Notes:



Additional contributors to the study include Edward B. Han and Stephen F. Heinemann, the Salk Institute; Celine M. DubГ© and Tallie Z. Baram, UC Irvine; and Stevan N. Djakovic and Gentry N. Patrick, UC San Diego Department of Neurobiology.



The study was funded in part by the National Institutes of Health, the Burroughs Wellcome Fund, the Howard Hughes Medical Institute and the Epilepsy Foundation.



Source: Debra Kain


University of California - San Diego

Observing Protein Movement With Super-Resolution

Scientists in Southampton, UK, and Ulm and Karlsruhe in Germany have shown that a variant form of a fluorescent protein (FP) originally isolated from a reef coral has excellent properties as a marker protein for super-resolution microscopy in live cells. Their findings have been published online by Nature Methods and will appear in print in the upcoming August issue of that journal.



Fluorescent proteins produced by a range of marine animals glow with a rainbow of colours, adding to the visual spectacle of coral reefs. Over recent years, molecular biologists have isolated a number of FPs and their genes, and used them to create genetically engineered variant FPs with particular light-emission characteristics.



"Fluorescent pigments from corals and related animals have proved to be invaluable lead structures to produce advanced markers for biomedical research," said Dr Jörg Wiedenmann of the University of Southampton's School of Ocean and Earth Science (SOES) based at the National Oceanography Centre, Southampton: "They enable a plethora of exciting experiments, including non-invasive study of dynamical processes within live cells,"



Photoactivatable FPs (PA-FPs)can, as their name suggests, be switched on by light. When light of a particular wavelength is shone upon them they start to glow, emitting light of characteristic hue.



Wiedenmann and his collaborators previously described EosFP, a PA-FP from the reef-building coral Lobophyllia. Genetic engineering yielded the variant IrisFP with dual photoactivation capacity. In one mode it is irreversibly 'photo-converted' from a green- to a red-emitting form under violet light. In a second mode, these two light-emitting forms can be switched on and off more or less at will using light of different wavelengths ('photo-switching').



For use in cell biology experiments, PA-FPs are genetically fused to proteins of interest, and expressed in live cells. Small regions of the cell are then illuminated with laser light of specific wavelength, causing the marker proteins to emit light at another wavelength. This allows dynamical cell processes to be visualised and studied under the microscope.



In the native state, four molecules of IrisFP join together to form a tetramer, creating problems for fusion-protein applications. To get round this, the researchers have now modified the protein by introducing four mutations. This makes individual IrisFP molecules (monomers) more stable, reducing their tendency for form tetramers.



"The monomeric variant, mIrisFP, maintains dual photoactivation capacity and has excellent properties as a genetically encoded fluorescent marker protein," explained Wiedenmann.



To test the usefulness of mIrisFP, the researchers genetically fused it with a number of other proteins within cultured cells. These included transcription factors, which regulate the expression of genes within the cell nucleus, and constituent proteins of the cell skeleton ('cytoskeleton'). In all cases, the fusion proteins functioned normally.



Further experiments demonstrated that mIrisFP fusion proteins could, as hoped, be used to study dynamical processes within live cells with a spatial resolution beyond the limits of conventional light microscopy. Specifically, the researchers successfully combined so-called pulse-chase experiments with photoactivation localisation microscopy (PALM) imaging to follow the movement of fluorescently marked fusion proteins over time and at very high spatial resolution.



"The dual photoactivation capability and the monomeric nature of mIrisFP should allow cell biologists to perform a wider range of experiments than possible using only conventional PA-FPs," said Wiedenmann.



"Marine animals such as corals and anemones are not only beautiful and important for ecosystem functioning, but also as source of fluorescent proteins of enormous value to biomedical research," he added.



The research was supported by the Deutsche Forschungsgemeinschaft and the State of Baden-WГјrttemberg through the Center for Functional Nanostructures, by Deutsche Forschungsgemeinschaft grant NI 291/9, Landesstiftung Baden-WГјrttemberg and Fonds der Chemischen Industrie.



The researchers are Jochen Fuchs, Susan Boehme,Per Niklas Hedde and Ulrich Nienhaus(Karlsruhe Institute of Technology),Franz Oswald(University of Ulm), Maike Krause (Institute of Biophysics, Ulm), and Jörg Wiedenmann(SOES).



Publication:


Fuchs, J., Boehme, S., Oswald, F., Hedde, P. N., Krause, M., Wiedenmann, J. & Nienhaus, G. U. A photoactivatable marker protein for pulse-chase imaging with superresolution. Nature Methods (Published online: 4 July 2010). | doi:10.1038/nmeth.1477



Source:

Dr. Rory Howlett


National Oceanography Centre, Southampton (UK)

New Biological Find Gives Consequences For Doping Offence

Article from the University of Oslo to appear in Proceedings of the National Academy of Sciences USA (PNAS) this week.


Exercise induces the incorporation of nuclei in muscle fibers that may help the fibers regain size upon retraining after a period of atrophy brought on by muscle disuse, according to a study.


Exercise enthusiasts know all too well that strength training of muscles leads to an increase in muscle size that is lost when the training is discontinued; the muscle fibers atrophy because of inactivity. But the mechanism by which previous episodes of training help atrophied fibers regain size relatively soon after retraining has long remained a mystery.


Professor Kristian Gundersen and colleagues at the Department of Molecular Biosciences, University of Oslo conducted imaging experiments on rodent muscles to find the cellular substrate for such 'muscle memory.' After an episode of overload exercise that resembled strength training, new nuclei were added to muscle fibers before the fibers grew in size, the authors found. The fibers retained the nuclei for a considerable time of the mouse life span after the overload was discontinued, the authors report. In addition, the nuclei helped delay muscle atrophy. Because the ability to create new muscle nuclei wanes with age, people may benefit from strength training at an early age, the authors suggest. Further, the relatively long-lasting muscle memory, likely encoded by the nuclei, implies that the length of time for which athletes are banned for a doping offense may need to be reevaluated, according to the authors.


Source: Oslo University

In Silico Cell For TB Drug Discovery, University Of Surrey, UK

A team of researchers from the University of Surrey have completed the
first genome-scale model of the microbe that causes tuberculosis. The
model may be a highly useful tool to identify new drug targets and
design new vaccines.


Tuberculosis remains one of the biggest killers in the world today being
responsible for nearly ten million cases and one and a half million
deaths each year. New strains are emerging that are resistant to all
current front-line anti-tuberculous drugs so new drugs are urgently
needed. However, little is known about the metabolism of the TB bacillus
and, because of its slow growth, experiments take a very long time.


The Surrey group hopes to speed up the drug discovery process by
building an in silico model of the agent that causes TB: a virtual TB
bacillus. This model was constructed using information from the entire
genome sequence of the pathogen and uses mathematical equations to model
the flow of nutrients through the cell. The model is extremely complex,
handling 848 different biochemical reactions and 726 genes. The Surrey
team showed that the model successfully simulates many of the peculiar
properties of the TB bacillus and identifies the drug targets of known
anti-tuberculous drugs. But unlike the biological organisms, the in
silico TB bacillus grows in nanoseconds so experiments that would
normally take months can be performed in minutes. The group hope that
the in silico model may be used to identify new drug targets,
particularly those capable of killing persistent bacilli.


The work is published in the high-profile journal Genome Biology and
describes not only the model but, for the first time, makes an in silico
model available to other researchers via an interactive website.
Researchers will be able to perform experiments on the virtual TB
bacillus from a beach in Bombay or a mountaintop in Malawi. It is hoped
that the availability of this novel research tool will stimulate new
approaches to control of this deadly pathogen.


The University of Surrey is one of the UK's leading professional,
scientific and technological universities with a world class research
profile and a reputation for excellence in teaching and research.
Ground-breaking research at the University is bringing direct benefit to
all spheres of life - helping industry to maintain its competitive edge
and creating improvements in the areas of health, medicine, space
science, the environment, communications, defence and social policy.
Programmes in science and technology have gained widespread recognition
and it also boasts flourishing programmes in dance and music, social
sciences, management and languages and law. In addition to the campus on
150 hectares just outside Guildford, Surrey, the University also owns
and runs the Surrey Research Park, which provides facilities for 140
companies employing 2,700 staff.


The Sunday Times names Surrey as 'The University for Jobs' which
underlines the university's growing reputation for providing high
quality, relevant degrees.


surrey.ac.uk

News From Journal Of Clinical Investigation Online Early: April 6, 2009

ONCOLOGY: Harnessing immune cells to target skin cancer



One subset of immune cells known to contribute to the immune response that targets tumors is the NK cell subset. Although this suggests that NK cell-based therapeutics have anticancer potential, more information is needed about the interactions between NK cells and human tumor cells if this promise is to be realized. A team of researchers, at The Babraham Institute, United Kingdom, and the University of Catanzaro "Magna Graecia", Italy, has now provided insight into this issue by studying both human metastatic melanomas (aggressive forms of skin cancer that have spread to other sites) and spontaneous mouse melanomas.



The team, led by Francesco Colucci and Ennio Carbone, found that human melanoma cell lines derived from lymph node metastases expressed proteins that interacted with the NK cell protein DNAM-1 and with a group of NK cell proteins known as NCRs. These cell lines were particularly susceptible to being killed by NK cells both in vitro and after being transplanted into mice. Consistent with these data from human cell lines, mouse spontaneous melanomas and melanoma cell lines both expressed proteins that bound DNAM-1 and NCRs. Further, interfering with the interaction of DNAM-1 and NCRs with proteins on melanoma cells reduced NK cell-mediated killing of human and mouse melanoma cells lines in vitro and in vivo. The authors therefore conclude that DNAM-1 and NCRs are critical for NK cell-mediated killing of melanoma cells and suggest that NK cells could be harnessed to prevent melanoma metastasis.



TITLE: NCRs and DNAM-1 mediate NK cell recognition and lysis of human and mouse melanoma cell lines in vitro and in vivo



AUTHOR CONTACT:

Francesco Colucci

The Babraham Institute, Cambridge, United Kingdom.

Ennio Carbone

University of Catanzaro "Magna Graecia", Catanzaro, Italy.



View the PDF of this article at: https://the-jci/article.php?id=36022



GASTROENTEROLOGY: The protein Cd1d controls intestinal colonization with bacteria



The intestines of all mammals, including humans, are home to a large number of species of bacteria. The identity of these bacteria affects both the normal functioning of the intestines and the occurrence of immune-mediated intestinal diseases, such as inflammatory bowel disease. Despite the importance of these bacteria, little is known about the host factors that control their colonization of the intestines. However, Edward Nieuwenhuis and colleagues, at Erasmus Medical Center, The Netherlands, have now identified a role for the protein Cd1d in regulating intestinal colonization by bacteria in mice.



In the study, when analyzed under specific pathogen-free or germ-free conditions and compared with Cd1d-sufficient mice, Cd1d-deficient mice exhibited increased colonization of the small intestine following administration of a number of species of bacteria (Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, or Lactobacillus gasseri) into their stomachs. By contrast, activation of immune cells that bind Cd1d prevented intestinal colonization of specific pathogen-free Cd1d-sufficient mice with P. aeruginosa and E. coli. Further analysis revealed a role for Paneth cells, which are found only in the small intestine, in the process. The authors therefore conclude that Cd1d controls colonization of the intestines with bacteria via a mechanism that involves Paneth cells and suggest that manipulating Cd1d might provide a way to modulate the identity of the bacteria in the intestines.
















TITLE: Cd1d-dependent regulation of bacterial colonization in the intestine of mice



AUTHOR CONTACT:

Edward E.S. Nieuwenhuis

Erasmus Medical Center, Rotterdam, The Netherlands.


View the PDF of this article at: https://the-jci/article.php?id=36509



PHYSIOLOGY: A link between low oxygen levels and intestinal iron absorption



The only way for iron, which is an essential nutrient, to be taken up by the body is for it to be absorbed by the intestine. Low iron levels can lead to anemia, which is characterized by weakness and fatigue and, in severe cases, heart failure. In a new study, Carole Peyssonnaux and her colleagues at UniversitГ© Paris Descartes, France, have identified a link between one of the HIF proteins that help cells adapt to low oxygen levels (hypoxia) and iron absorption in the small intestine, which they found was hypoxic. Using transgenic mice, they showed that HIF-2-alpha (but not HIF-1-alpha) helped maintain iron levels in the intestine by regulating expression of the primary iron transporter gene. Furthermore, mice lacking HIF-2-alpha displayed low levels of iron in the blood and liver. The authors therefore conclude that strategies targeting HIF-2-alpha may be useful in treating patients with iron disorders.



TITLE: HIF-2-alpha, but not HIF-1-alpha, promotes iron absorption in mice



AUTHOR CONTACT:

Carole Peyssonnaux

UniversitГ© Paris Descartes, CNRS (UMR 8104), Paris, France.



View the PDF of this article at: https://the-jci/article.php?id=38499



NEPHROLOGY: Fragmenting mitochondria underlie acute kidney failure



Damage to kidney cells known as renal tubular cells is a major cause of acute kidney failure, which is increasing in prevalence. In particular, damage to the energy generating compartments of the cell, which are known as mitochondria, is central to renal tubular cell death. Zheng Dong and colleagues, at the Medical College of Georgia, Augusta, have now provided new insight into the mitochondrial changes that occur in acute rodent kidney injury, information that they hope might provide new avenues of research for those developing drugs to combat this condition.



In the study, analysis of rat renal tubular cells in vitro following exposure to conditions that induce acute kidney injury in vivo, revealed that mitochondria fragmented before the cells died. Furthermore, both knocking down expression of the protein Drp1, which is known to be involved in mitochondrial fission, and blocking its function substantially reduced mitochondrial fragmentation and apoptotic cell death. Consistent with these data, mitochondrial fragmentation was observed in two mouse models of acute kidney injury and treatment with a newly identified pharmacological inhibitor of Drp1 reduced renal tubular cell apoptosis and acute kidney injury.



TITLE: Regulation of mitochondrial dynamics in acute kidney injury in cell culture and rodent models



AUTHOR CONTACT:

Zheng Dong

Medical College of Georgia, Augusta, Georgia, USA.



View the PDF of this article at: https://the-jci/article.php?id=37829



Source:
Karen Honey


Journal of Clinical Investigation

Re-awakening Old Genes To Help In The Fight Against Viruses

A paper published in this week's issue of PLoS Biology describes a study
that has reactivated a dormant gene found in humans and coaxed it - in
tissue culture - to produce an antiviral peptide. Lead scientist Alexander
Cole used aminoglycosides - drugs commonly used to fight bacterial
infections - to trigger the production of the protein, which is encoded by
the dormant human defensin gene that he calls 'retrocyclin'. The
authors hope that this research might ultimately lead to the development
of a treatment that would activate the gene in a person's own cells, for
example, and thereby prevent infection with viruses in the treated tissue.



This research "could make a difference in the fight against viruses such
as HIV," said corresponding author Dr. Cole. "Much more work would be
needed to demonstrate the safety and effectiveness of this approach. We
would certainly have to have human trials, but these findings represent a
promising step in that direction."



Dozens of scientists around the world are looking for ways to prevent the
transmission of viruses such as HIV. Cole and colleagues have previously
discovered that retrocyclin proteins found in some primates appeared to
prevent HIV infections in cell cultures. The same gene exists in humans,
but
because of a mutation that interrupts the gene sequence, it no longer
produces protein.



Now, a collaboration between researchers at UCLA, the Centers for Disease
Control, and Cole's team at the University of Central Florida has found
that restoring the production of retrocyclins prevents HIV entry into
human cells. The scientists have found a way to get the gene to produce
the
retrocyclin and then showed that the retrocyclin appears to prevent the
transmission of HIV in cells cultured in the laboratory. They applied
aminoglycoside antibiotics to vaginal tissues and cervical cells in the
lab and found the antibiotic appears to stimulate those cells and tissues
to
produce retrocyclins on their own.



Cole said he believed there is a possibility the aminoglycoside
antibiotics will be used in a cream or gel format that could someday be a
simple way
to prevent the transmission of HIV. Much more work would be required
before this would be possible, including taking the result in tissue
culture and
showing the same effect in whole organisms.



Funding - This work was supported by grants AI052017 and AI065430 (to
A.M.C) from the National Institutes of Health. The funders had no role in
study
design, data collection and analysis, decision to publish, or preparation
of the manuscript.



Competing interests statement - The authors declare that no competing
interests exist.



Citation:

"Reawakening retrocyclins: ancestral human defensins active against HIV-1."
Venkataraman N, Cole AL, Ruchala P, Waring AJ, Lehrer RI, et al. (2009)

PLoS Biol 7(4):e1000095. doi:10.1371/journal.pbio.1000095


Source
Plos Biology

Blocking Signaling Protein Prevents Prostate Cancer Spread, Jefferson Scientists Find

Researchers at the Kimmel Cancer Center at Jefferson in Philadelphia have shown that by blocking a signaling protein, they can prevent prostate cancer cells from metastatic dissemination. The work opens the door to future studies examining the protein as a target for therapies aimed at keeping prostate cancer at bay.



In a series of experiments in both the laboratory and animal models, Marja Nevalainen, M.D., Ph.D., associate professor of Cancer Biology at Jefferson Medical College of Thomas Jefferson University and her co-workers found that the protein, Stat3, is key to the metastatic progression of prostate cancer. Dr. Nevalainen's group reports its findings in the June 2008 issue of the American Journal of Pathology.



According to Dr. Nevalainen, previous studies have shown that Stat3 is very active in metastatic prostate cancer, and the protein has been linked to cancer metastasis in several different cancer types. Because metastatic prostate cancer lacks effective therapies, understanding the molecular changes involved is critical.



To clarify Stat3's role in prostate cancer progression, she and her co-workers performed several studies. In one case, the scientists used an antibody for Stat3, for example, to show that it is activated in 77 percent of lymph nodes and 66 percent of bone metastases in human prostate cancer. In another experiment, the scientists prompted mouse prostate cancer cells to overproduce the normal Stat3 protein by delivering it through a virus vehicle. They saw a dramatic increase in prostate cancer metastases compared to controls.



Specifically, in mice lacking a working immune system, they showed that Stat3 caused a 33-fold increase in metastases.



"This is the first proof that Stat3 may have a major effect on metastatic dissemination of prostate cancer," Dr. Nevalainen says. "Stat3 now becomes a potential drug target to interfere with the metastatic progression of prostate cancer."



While her team's results "open up other opportunities to study the mechanism of prostate cancer metastases," Dr. Nevalainen notes that Stat3 might have possible use in the prevention of primary prostate cancer from progressing to metastatic disease as well.



She suggests that studies testing newly developed Stat3 inhibitors in prostate cancer should include testing their effectiveness in blocking prostate cancer metastases in experimental animal models.






Source: Steve Benowitz


Thomas Jefferson University

MRI Reveals Secrets Of Animal Anatomy

Danish scientists have used Computer Tomography (CT) and Magnetic Resonance Imaging (MRI) to investigate internal organs in animals including alligators, snakes and tarantulas.



Images revealed, for the first time non-invasively, how a snake adapts its internal organs in preparation for a big meal and during digestion, until it has disappeared completely.



The scientists think MRI and CT images of animal anatomy could be valuable supplements to traditional textbook sketches, diminishing the need for invasive research and dissections.



The new research, presented on Wednesday 30th June 2010 at the Society for Experimental Biology Annual Meeting in Prague, is the first time the complete digestion cycle of a Burmese Python has been visualised with modern MRI and CT imaging techniques.



'Pythons are renowned for their ability to fast for many months and ingest very large meals', explained Kasper Hansen, from the Aarhus University in Denmark. Modern scanning techniques have shown how extreme adaptations of the internal organs allow the snake to accommodate this 'feast and famine' lifestyle.



Fasting Burmese pythons (Python molurus) were scanned before and at 2, 16, 24, 40, 48, 72 and 132 hours after ingestion of one rat. The succession of images revealed a gradual disappearance of the body of the rat, accompanied by an overall expansion of the intestine, shrinking of the gallbladder, and a 25% increase in heart volume.



The scientists think the technique may be useful in showing the ability of organs to show extreme anatomical adaptations, known as phenotypic flexibility, in other species.



The team used a combination of Computer Tomography (CT), which is suited to hard tissue (bones, teeth, shell etc) and MRI, more suitable for soft tissue, to visualise the entire internal organ structures and vascular systems of their subjects.



"Because of the changes induced by dissection, ordinary illustrations tend to be a bit subjective and sometimes misleading", explained Kasper Hansen. "For example, after opening the dense bone of a turtle shell, the lungs will collapse due to a change in interthoracic pressure".



"Instead, we were able to produce high resolution 3D digital models of animal soft and hard tissue anatomy within hours", explained Henrik Lauridsen, a student in the research team.



The images produced by the techniques could be a valuable tool in future studies of animal anatomy for research and education purposes, according to the scientists.



By choosing the right settings for contrast and light intensity during the scanning process, the scientists were able to highlight specific organs and make them appear in different colours.



Some species such as turtles, swamp eels and bearded dragons were also injected contrasting agents, which allowed the scientists to investigate their vasculature (blood vessels).



Source:

Roz Pidcock


Society for Experimental Biology

Tumor Immunologist Jose R. Conejo-Garcia Joins The Wistar Institute

The Wistar Institute has appointed ovarian cancer researcher JosГ© R. Conejo-Garcia, M.D., Ph.D., as associate professor in the Institute's Immunology Program. Conejo-Garcia comes to Wistar from Dartmouth Medical School.


Conejo-Garcia's laboratory program explores an innovative approach to fighting ovarian cancer by exploiting the tumor's reliance on its "microenvironment," the collection of neighboring, healthy cells that nourish the tumor and enable it to thrive. In particular, he has developed a "Trojan Horse" method that reprograms white blood cells within the microenvironment which otherwise have the effect of preventing the spontaneous anti-tumor activity of the immune system so that they activate immune cells to attack the ovarian tumor.


"Dr. Conejo-Garcia has established himself as an important thinker in the study of the tumor microenvironment, an emerging field of cancer biology that is of particular interest to our scientists," said Wistar President and CEO Russel E. Kaufman, M.D. "His expertise bridges our Immunology and Molecular and Cellular Oncogenesis programs and will strengthen collaborations across The Wistar Institute Cancer Center."


Born and educated in Spain, Conejo-Garcia received his medical degree from the University of Zaragoza in 1990. After completing a residency in Clinical Chemistry at the University Hospital of Guadalajara, he began to work toward a Ph.D. in Molecular Oncology at the University of Alcala. In 1998, Conejo-Garcia began post-doctoral work at the University of Bern in Switzerland, where he delved deeper into the study of tumor biology.


After two years working in a biotechnological company in Germany, Conejo-Garcia took a second post-doctoral fellowship in 2001, this time at the University of Pennsylvania, where he applied his interest in tumor biology to the study of ovarian cancer. It was then he began to focus on the tumor microenvironment, a theme that he carried with him to Dartmouth, where he became an assistant professor in 2005.


Conejo-Garcia's current research explores the biology of a subset of immune cells known as dendritic cells, which are co-opted by ovarian tumors to protect them from the immune system as a whole, rather than boosting protective immune responses. His laboratory has discovered that eliminating these immune cells from the tumor microenvironment kills ovarian tumor cells and may slow aggressive forms of the cancer.


These dendritic cells may also form the basis of a drug delivery system, a means of sneaking cancer-killing particles into ovarian tumors. This Trojan Horse approach, Conejo-Garcia says, may lead to better complementary or individual therapies to treat ovarian cancer, a disease that kills about 15,000 American women each year.


Source: Wistar Institute

Worm Genome Offers Clues To Evolution Of Parasitism

The genome of a humble worm that dines on the microbial organisms covering the carcasses of dead beetles may provide clues to the evolution of parasitic worms, including those that infect humans, say scientists at Washington University School of Medicine in St. Louis and the Max-Planck Institute for Developmental Biology in Germany.



In a paper published in the current issue of Nature Genetics, the researchers reported finding some surprises as they have decoded the genome of the worm, a tiny nematode called Pristionchus pacificus.



"We found a larger number of genes than we expected," says Sandra Clifton, Ph.D., research assistant professor of genetics and a co-author of the paper. "These include genes that help the worms live in a hostile environment, the result of living in and being exposed to the byproducts of decaying beetle carcasses, and others that also have been found in plant parasitic nematodes. The genome supports the theory that P. pacificus might be a precursor to parasitic worms."



Scientists estimate there are tens of thousands of nematode species. The worms are typically just one millimeter long and can be found in every ecosystem on Earth. Parasitic nematodes can infect humans as well as animals and plants.



One nematode in particular is well known in scientific circles: Caenorhabditis elegans has long been used as a model organism in research laboratories. Its genome sequence was completed in 1998 by Washington University genome scientists working as part of an international research collaboration.



Unlike C. elegans, which lives in the dirt, P. pacificus makes its home in an unusual ecological niche: it lives together with oriental beetles in the United States and Japan in order to devour the bacteria, fungi and other small roundworms that grow on beetle carcasses after they have died. While the beetles are alive and the nematodes' food source is scarce, the worms live in a "resting" stage in which they don't eat or reproduce.



This suspended state, called dauer diapause, is thought to be the infective state of parasitic nematodes. According to the World Health Organization, parasitic nematodes infect about 2 billion people worldwide and severely sicken some 300 million.



The genome of P. pacificus is substantially larger and more complex than C. elegans. It has nearly 170,000 chemical bases and contains 23,500 protein-coding genes. By comparison, C. elegans and the human parasitic nematode Brugia malayi, whose genome was sequenced in 2007, only have about 20,000 and 12,000 protein-coding genes, respectively. Infection with B. malayi causes lymphatic filariasis, which can lead to elephantiasis, a grotesque enlargement of the arms, legs and genitals.



Interestingly, the P. pacificus genome contains a number of genes for cellulases - enzymes that are required to break down cell walls of plants and microorganisms. These genes are nonexistent in C. elegans, although they have been found in plant parasitic nematodes. "Using genetic tools, we can analyze the development, behavior and ecology of this highly unusual worm to aid in understanding the evolutionary changes that allowed parasitism to occur," says co-author Richard K. Wilson, Ph.D., director of Washington University's Genome Sequencing Center.







The P. pacificus genome was sequenced at Washington University; Ralf Sommer, Ph.D., and colleagues at the Max-Planck Institute supplied the DNA for sequencing and analyzed the sequence data.



The research was funded by the National Human Genome Research Institute and the Max-Planck Society.



Dieterich C, Clifton S, Schuster L, Chinwalla A, Delehaunty K, Dinkelacker I, Fulton L, Fulton R, Godfrey J, Minx P, Mitreva M, Roeseler W, Tian H, Witte H, Yang S-P, Wilson R, Sommer RJ



The genome sequence of Pristionchus pacificus provides a unique perspective on nematode life-style and the evolution toward parasitism.



Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.



Source: Caroline Arbanas


Washington University School of Medicine

Research Team Wins Funds To Unravel A DNA Mystery

An international research team headed by two University of Adelaide researchers has been awarded a US$900,000 grant to help unravel the phenomenon of "DNA looping".



DNA looping is responsible for controlling the expression of genes in cells. It is believed to play a key role in a number of diseases, including many cancers.



The looping occurs due to the binding of proteins to different regions of the DNA. These proteins interact with each other so that the DNA loops in between them.



The funding, from the Human Frontier Science Program based in France, has been awarded to Dr Keith Shearwin and Dr Ian Dodd in the University's School of Molecular and Biomedical Science.



Their research aims to discover how the correct DNA loops are formed to ensure that the right gene is turned on at the right time and place.



This will be done by comparing DNA looping inside the cell with looping in the test tube and with predictions obtained through computer simulation.



Dr Shearwin and Dr Dodd will be designing the DNA sequences that will be used for the project and will be testing DNA looping inside the cell.



"It is basic research which underpins applied science. Understanding how genes are controlled has huge implications for health and for anything that depends on biology, not only for humans but also all sorts of organisms," Dr Dodd said.



"There are some diseases known which seem to be caused by incorrect looping interactions and improper control of gene interactions - including some cancers," Dr Shearwin said.



"Anything we can do to help explain the processes involved could go some way towards helping future research into cancer and other diseases, which is why this basic research has attracted international interest and funding."



Dr Shearwin is a lecturer in biochemistry, with his main research areas being the control of gene expression and the processes involved in genetic development.



Dr Dodd, who has been awarded the William Elliott Biochemistry Research Fellowship, carries out research in molecular biology with a strong interest in using mathematical models to understand complex systems.



Dr Shearwin and Dr Dodd will be working with two teams from Atlanta and Pittsburgh over the next three years.



Source:
Dr. Keith Shearwin


University of Adelaide

Total Nutraceutical Solutions Mushroom Study Reveals Increased Biologic Survival

Total Nutraceutical Solutions, Inc. (TNS) (OTCBB:TNUS), announced today that a proprietary grown mushroom, Agaricus blazei Murill (AbM) by Sylvan Bio, Inc. and Creekside Mushrooms Limited, has shown a significant increase in survival of a live biologic model, Drosophila melanogaster (Drosophila).


This study revealed that ingestion of a natural organic edible whole food could increase biologic survival. Unaltered and Vitamin D2 enriched AbM dried powders significantly increased survival above controls, 4% and 15% respectively. The study was performed under contract by Model BioSystems Inc, using a proprietary Drosophila biologic model developed in the laboratory of Dr. Krishna Bhat, University of Texas, Galveston, Texas. This unique live model system can evaluate the effect of a given compound/ingredient for survival on a nutritionally deficient diet. The fruit fly, now a standard model in genetic research, is an ideal research tool since it develops from fertilized egg to embryo within nine days. A special proprietary preparation of AbM was prepared and enriched with Vitamin D2 by exposure to short bursts of pulsed UV light and complete natural dried powders of AbM, unexposed and exposed, were studied in a blinded investigator protocol; the total study involved over 1,000 Drosophila with 120 organisms in each group.


Vitamin D, called the 'sunshine vitamin,' has recently received much attention as a needed nutritional supplement to improve human health. Decreased levels of Vitamin D have been associated with a range of diseases, such as osteoporosis, osteoarthritis, cancer of the breast, diabetes, cardiovascular disease, and many others.


TNS has filed a "Use Patent Application" on these breakthrough nutritional findings with the United States Patent Office.


"The ability of a natural organic whole food, such as Agaricus blazei Murill, to increase biologic survival, is a welcome development in healthcare as more and more people demand natural alternatives to prevent disease and potentially slow down the aging process," stated Marvin S. Hausman MD, CEO, Total Nutraceutical Solutions, Inc. "These new and exciting results have the potential to empower people worldwide with a key wellness tool."


"We believe that the unique, proprietary technology used to produce these mushrooms, contributes significantly to the success of the TNS study," commented Dr. Mark Wach, Sylvan's Vice President and Director of Research. "We are excited about the use of live biologic models in helping to quantify the healthcare potential of our mushroom products."


Sylvan Bio, Inc. is an emerging leader in providing innovative fungal products to a variety of industries. Based in Kittanning, Pennsylvania, it is a wholly owned subsidiary of Sylvan Inc., also based in Kittanning. Sylvan Inc. serves mushroom, agricultural and nutraceutical markets through its prominence in fungal technology and solid-substrate fermentation.


Creekside Mushrooms Limited is the largest single site fully integrated and highly technological "underground" mushroom growing farm in the world. Creekside's unique underground farm is scientifically monitored to provide ideal year-round growing conditions to consistently produce the highest quality mushrooms, which are 100% organic.


Source

Total Nutraceutical Solutions, Inc.

What Does Swine Flu Do To Pigs?

The effects of H1N1 swine flu have been investigated in a group of piglets. Scientists writing in BioMed Central's open access Virology Journal studied the pathology of the virus, finding that all infected animals showed flu-like symptoms between one and four days after infection and were shedding virus two days after infection.



Roongroje Thanawongnuwech led a team of researchers from Chulalongkorn University, Bangkok, who infected 22-day old pigs with both the H1N1 strain of swine flu and the less dangerous H3N2 subtype. He said, "The results demonstrated that both swine flu subtypes were able to induce flu-like symptoms and lung lesions in weanling pigs. However the severity of the disease with regard to both gross and microscopic lung lesions was greater in the H1N1-infected pigs".



All infected pigs developed respiratory symptoms such as nasal discharge, coughing, sneezing and conjunctivitis. Upon pathological examination, lung lesions large enough to be seen by the naked eye were observed. According to Thanawongnuwech, "These lesions were characterized by dark plum-colored, consolidated areas on lung lobes and were most severe two days after infection, especially in the H1N1-infected pigs, where approximately a third of the lung was covered". The course of infection was limited to less than a week and none of the animals died.



Pathogenesis of swine influenza virus (Thai isolates) in weanling pigs: an experimental trial

Donruethai Sreta, Roongtham Kedkovid, Sophon Tuamsang, Pravina Kitikoon and Roongroje Thanawongnuwech

Virology Journal 2009, 6:34 doi:10.1186/1743-422X-6-34

virologyj/content/6/1/34



Source:
Graeme Baldwin


BioMed Central

Viable Target For Drugs Holds Promise In The Treatment Of Cancers

By bypassing a well-known gene implicated in almost one-third of all cancers and instead focusing on the protein activated by the gene, Duke University Medical Center researchers believe they may have found a new target for anti-cancer drugs.



In experiments with human cells and animal models, the researchers studied the gene known as 'Ras,' which is integral in normal cell growth. When this gene is mutated and becomes overactive, it can lead to the unregulated proliferation of cells that is the hallmark of tumor formation.



The ras gene, known as an oncogene when it is in this mutated state, has been implicated in several different cancers, including those of the pancreas and lungs. To date, efforts at blocking or turning off ras have proven ineffective. Pancreatic cancer has been shown to have the strongest link to the ras oncogene, and it is also one of the hardest cancers to treat, with few patients alive five years after diagnosis, researchers said.



"Since it has been so difficult to target the ras gene itself with drugs, we tried to determine if something that ras activates could be a possible target for a drug or therapy," said Christopher Counter, Ph.D., associate professor of pharmacology and cancer biology and senior member of the research team. "We found a specific target that could be susceptible to drugs, and if these findings are proven true in human trials, we could have a new way of treating ras-dependent cancers."



The results of the Duke experiments were published July 15, 2007, in the journal Genes & Development. Brooke Ancrile, a graduate student in Counter's laboratory, was first author of the paper. The research was supported by the National Institutes of Health.



The researchers discovered that the overactive ras gene was responsible for above-normal secretion of a factor known as interleukin-6 (IL-6). Scientists know a great deal about IL-6 and its functions in the body, but its link to oncogenic ras was unknown.



In addition to finding that the ras oncogene spurred the production of IL-6, they also found that inhibiting IL-6 production reduced the creation of new blood vessels, which are crucial for the development and nourishment of tumors.



"IL-6 was like the gas pedal driving the growth of tumors," Counter said. "No gas, no growth, which is exactly what we saw when we inhibited IL-6 in tumors."



Counter is encouraged that even though these findings are in cell culture and animal models, therapies based on targeting IL-6 in cancers driven by the ras oncogene could be tested in humans in the near future. A biotechnology company has already developed a monoclonal antibody specific to IL-6 which could be used to neutralize IL-6.



A phase II trial is underway testing a monoclonal antibody against IL-6 for patients with multiple myeloma, a cancer that depends on IL-6 but is not known to have a connection to the ras oncogene. If the results of this trial are positive, studies might begin in ras-dependent cancers. Counter's group is actively pursuing the idea that such an antibody may inhibit pancreatic cancer growth in mouse models. If these results are positive, this will open the door for Duke oncologists to organize a clinical trial to test the agent in human cancer patients.



"Secreted proteins promoting the growth of blood vessels in tumors have been successfully neutralized in the past with antibodies," Ancrile said. "We believe that IL-6 is a viable target for drugs that holds promise in the treatment of cancers dependent on the ras oncogene."







Duke's Kian-Huat Lim was also a member of the research team.



Source: Richard Merritt


Duke University Medical Center

Promise For Exploring, Treating Alzheimer's Shown By Hybrid Molecules

One of the many mysteries of Alzheimer's disease is how protein-like snippets called amyloid-beta peptides, which clump together to form plaques in the brain, may cause cell death, leading to the disease's devastating symptoms of memory loss and other mental difficulties.



In order to answer that key question and develop new approaches to preventing the damage, scientists must first understand how amyloid-beta forms the telltale clumps.



University of Michigan researchers have developed new molecular tools that can be used to investigate the process. The molecules also hold promise in Alzheimer's disease treatment. The research, led by assistant professor Mi Hee Lim, was published online this week in the Journal of the American Chemical Society.



Though the exact mechanism for amyloid-beta clump formation isn't known, scientists do know that copper and zinc ions are somehow involved, not only in the aggregation process, but apparently also in the resulting injury. Copper, in particular, has been implicated in generating reactive oxygen species, which can cause cell damage.



One way of studying the role of metals in the process is by sopping up the metal ions with molecules called chelators and then seeing what happens when the metal ions are out of the picture. When other scientists have done this they've found that chelators, by removing metals, hamper both amyloid beta clumping and the production of those harmful reactive oxygen species, suggesting that chelators could be useful in treating Alzheimer's disease.



However, most known chelators can't cross the blood-brain barrier, the barricade of cells that separates brain tissue from circulating blood, protecting the brain from harmful substances in the bloodstream. What's more, most chelators aren't precise enough to target only the metal ions in amyloid-beta; they're just as likely to grab and disable metals performing vital roles in other biological systems.



Lim and coworkers used a new strategy to develop "bi-functional" small molecules that not only grab metal ions, but also interact with amyloid-beta.



"The idea is simple," said Lim, who has joint appointments in the Department of Chemistry and the Life Sciences Institute. "We found molecules known for amyloid-beta recognition and then attached metal binding sites to them." In collaboration with Ayyalusamy Ramamoorthy, professor of chemistry and associate professor of biophysics, Lim then used NMR spectroscopy to confirm that the new, hybrid molecules still interacted with amyloid-beta.



In experiments in solutions with or without living cells, the researchers showed that the bi-functional molecules were able to regulate copper-induced amyloid-beta aggregation, not only disrupting the formation of clumps, but also breaking up clumps that already had formed. In fact, their molecules performed better than clioquinol, a clinically-available metal chelator that showed promise in early trials with Alzheimer's patients, but has side effects that limit its long-term use.



"Based on their small size and other properties, we believe our compounds will be able to cross the blood-brain barrier, but we want to confirm that using mouse models," Lim said. The researchers also plan experiments to see if their new chelators are as good at preventing and breaking up amyloid-beta plaques in the brains of mice as they are in solutions and cultured cells.



In addition to Lim and Ramamoorthy, coauthors include postdoctoral fellow Sarmad Hindo, graduate students Allana Mancino and Joseph Braymer, lab technician Yihong Liu, and NMR specialist Subramanian Vivekanandan.



The research was supported by U-M and the National Institutes of Health.



Source: Nancy Ross-Flanigan


University of Michigan

News From The Journal Of Neuroscience, 13-Jan-2009

1. Glutamate Binding Is Required for AMPA Receptor Trafficking


Sarah K. Coleman, Tommi Möykkynen, Annukka Jouppila, Susanna Koskelainen, Claudio Rivera, Esa R. Korpi, and Kari Keinänen



Many quality-control mechanisms prevent expression of mutated or misfolded proteins in cells. For transmembrane proteins, regulation of folding and assembly occurs in the endoplasmic reticulum (ER), where chaperone proteins bind to misfolded proteins and prevent further transport along the secretory pathway. Chaperones are thought to recognize misfolded proteins by binding to domains that are hidden when the protein is properly folded. Conformationally unstable proteins that fluctuate between properly and improperly folded states are more likely to expose these domains, and thus are inefficiently trafficked through the ER. For some such proteins, binding of "pharmacological chaperones" increases stability and facilitates exit from the ER. This week, Coleman et al. report that point mutations that eliminate glutamate binding prevented delivery of AMPA receptors to the plasma membrane in neurons. Because previous studies showed that glutamate binding increases stability of AMPA receptors, these data suggest glutamate is a pharmacological chaperone required for trafficking of AMPA receptors.



2. Neurotrophins Differentially Affect Neuronal Firing


MarГ­a A. Davis-LГіpez de Carrizosa, Camilo J. Morado-DГ­az, Juan J. Tena, Beatriz BenГ­tez-TemiГ±o, MarГ­a L. Pecero, Sara R. Morcuende, Rosa. R. de la Cruz, and Angel M. Pastor



Neurotrophins act throughout life to promote cell survival, synaptogenesis, and synaptic maintenance. Muscle-derived neurotrophins not only affect innervating motor neurons, but also act transsynapitcally, influencing efferent inputs to motor neurons. Davis-LГіpez de Carrizosa et al. now show that individual neurotrophins can differentially affect efferent inputs to motor neurons in vivo. After the abducens nerve was detached from its target muscle, abducens motor neurons lost synaptic inputs and fired at lower rates. Both tonic spiking, triggered by prepositus hypoglossi nucleus (PHN) inputs and associated with fixed gaze, and burst firing, triggered by pontine reticular formation inputs and associated with saccades, were reduced. Brain-derived neurotrophic factor (BDNF) and/or neurotrophin-3 (NT-3) restored synaptic inputs but produced different effects on spiking. BDNF restored tonic firing, but not bursting, suggesting that it restored inputs from the PHN but not from the reticular formation. NT-3 had complementary effects, suggesting that it restored reticular inputs but not PHN inputs.



3. Reconsolidation and Extinction Activate CREB in Distinct Areas


Nori Mamiya, Hotaka Fukushima, Akinobu Suzuki, Zensai Matsuyama, Seiichi Homma, Paul W. Frankland, and Satoshi Kida



Contextual fear memory is produced in mice by administering a foot shock shortly after introducing a mouse to a new environment. If the mouse is returned to the feared environment for a brief period without shock, the initial fear memory is reconsolidated; but if the mouse is re-exposed for a longer period without shock, the fear is extinguished. According to Mamiya et al., reconsolidation and extinction depend on gene expression in distinct brain areas. With reconsolidation, cAMP-responsive element-binding protein (CREB) was activated in the hippocampus and amygdala, and expression of at least one CREB target, activity-regulated cytoskeleton-associated protein (Arc), increased in these areas. After extinction, CREB activity and Arc expression increased in amygdala and prefrontal cortex. Distinct roles of these brain regions were further demonstrated by blocking protein synthesis: blocking synthesis in hippocampus blocked reconsolidation, but not extinction, whereas blocking synthesis in prefrontal cortex had the opposite effect.
















4. Loss of Doublecortin Alters Cortical Network Activity


James B. Ackman, Laurent Aniksztejn, ValГ©rie CrГ©pel, HГ©lГЁne Becq, Christophe Pellegrino, Carlos Cardoso, Yehezkel Ben-Ari, and Alfonso Represa



Mutations in the microtubule-associated protein doublecortin disrupt migration of cortical neurons in humans, producing an ectopic layer of neurons beneath the normal cortex and resulting in mental retardation and epilepsy. To examine neuronal activity associated with such defects, Ackman et al. knocked down doublecortin expression in nascent layer 2/3 (L2/3) neurons of rats using in utero RNA interference. Neurons transfected with shRNAs targeting doublecortin formed ectopic clusters in white matter and deep cortical layers. Although the frequency of spontaneous EPSCs and IPSCs in these neurons was much lower than in normal L2/3, their spontaneous activity was higher. Interestingly, the presence of ectopic neurons had consequences for untransfected L2/3 neurons, which migrated to the appropriate layer, but had much higher spontaneous EPSC frequency than neurons in normal L2/3. Ectopic and overlying L2/3 neurons were interconnected and were frequently coactive, and perfusion with magnesium-free medium induced correlated epileptiform activity across the two populations.







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Source: Sara Harris


Society for Neuroscience