LA JOLLA – Engineering Evil

‘Alien’ life form is grown in a lab: Scientists add unnatural DNA strands to the genetic code of bacteria to create a new strain

Researchers at the Scripps Research Institute in La Jolla, California, introduced DNA molecules not found in nature to a common bacterium
The E. coli bugs are able to grow and reproduce as normal despite containing two extra letters in their genetic code
Research involved overcoming a billion years of evolution to get the expanded genetic alphabet into living bacteria
In the future the research could lead to creation of microbes capable of manufacturing entirely new proteins that could be used in medicine
Some people are worried that the rapid advance of ‘synthetic biology’ could lead to the worrying prospect of new life-forms escaping from labs

Continue reading “‘Alien’ life form is grown in a lab: Scientists add unnatural DNA strands to the genetic code of bacteria to create a new strain”

‘Junk DNA’ drives embryonic development

Contact: Heather Buschman, Ph.D. hbuschman@sanfordburnham.org 858-795-5343 Sanford-Burnham Medical Research Institute

Sanford-Burnham researchers discover that microRNAs play an important role in germ layer formation—the process that determines which cells become which organs during embryonic development



		IMAGE: These are differentiating mouse embryonic stem cells (green = mesoderm progenitor cells, red = endoderm progenitor cells). The microRNAs identified in this study block endoderm formation, while enhancing mesoderm formation.Click here for more information.

LA JOLLA, Calif., December 3, 2012 – An embryo is an amazing thing. From just one initial cell, an entire living, breathing body emerges, full of working cells and organs. It comes as no surprise that embryonic development is a very carefully orchestrated process—everything has to fall into the right place at the right time. Developmental and cell biologists study this very thing, unraveling the molecular cues that determine how we become human.

“One of the first, and arguably most important, steps in development is the allocation of cells into three germ layers—ectoderm, mesoderm, and endoderm—that give rise to all tissues and organs in the body,” explains Mark Mercola, Ph.D., professor and director of Sanford-Burnham’s Muscle Development and Regeneration Program in the Sanford Children’s Health Research Center.

In a study published in the journal Genes & Development, Mercola and his team, including postdoctoral researcher Alexandre Colas, Ph.D., and Wesley McKeithan, discovered that microRNAs play an important role in this cell- and germ layer-directing process during development.

MicroRNA: one man’s junk is another’s treasure

MicroRNAs are small pieces of genetic material similar to the messenger RNA that carries protein-encoding recipes from a cell’s genome out to the protein-building machinery in the cytoplasm. Only microRNAs don’t encode proteins. So, for many years, scientists dismissed the regions of the genome that encode these small, non-protein coding RNAs as “junk.”

We now know that microRNAs are far from junk. They may not encode their own proteins, but they do bind messenger RNA, preventing their encoded proteins from being constructed. In this way, microRNAs play important roles in determining which proteins are produced (or not produced) at a given time.

MicroRNAs are increasingly recognized as an important part of both normal cellular function and the development of human disease.

So, why not embryonic development, too?

Directing cellular traffic

To pinpoint which—if any—microRNAs influence germ layer formation in early embryonic development, Mercola and his team individually studied most (about 900) of the microRNAs from the human genome. They tested each microRNA’s ability to direct formation of mesoderm and endoderm from embryonic stem cells. In doing so, they discovered that two microRNA families—called let-7 and miR-18—block endoderm formation, while enhancing mesoderm and ectoderm formation.

The researchers confirmed their finding by artificially blocking let-7 function and checking to see what happened. That move dramatically altered embryonic cell fate, diverting would-be mesoderm and ectoderm into endoderm and underscoring the microRNA’s crucial role in development.



		IMAGE: Mark Mercola, Ph.D., is a professor and program director at Sanford-Burnham Medical Research Institute.Click here for more information.

But they still wanted to know more…how do let-7 and miR-18 work? Mercola’s team went on to determine that these microRNAs direct mesoderm and ectoderm formation by dampening the TGFβ signaling pathway. TGFβ is a molecule that influences many cellular behaviors, including proliferation and differentiation. When these microRNAs tinker with TGFβ activity, they send cells on a certain course—some go on to become bone, others brain.

“We’ve now shown that microRNAs are powerful regulators of embryonic cell fate,” Mercola says. “But our study also demonstrates that screening techniques, combined with systems biology, provide a paradigm for whole-genome screening and its use in identifying molecular signals that control complex biological processes.”

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This research was funded by the California Institute for Regenerative Medicine, the U.S. National Institutes of Health (National Heart, Lung, and Blood Institute grants R33 HL088266 and R01 HL113601), and the American Heart Association.

Original paper:

Colas AR, McKeithan WL, Cunningham TJ, Bushway PJ, Garmire LX, Duester G, Subramaniam S, & Mercola M (2012). Whole-genome microRNA screening identifies let-7 and mir-18 as regulators of germ layer formation during early embryogenesis. Genes & development PMID: 23152446

About Sanford-Burnham Medical Research Institute

Sanford-Burnham Medical Research Institute is dedicated to discovering the fundamental molecular causes of disease and devising the innovative therapies of tomorrow. The Institute consistently ranks among the top five organizations worldwide for its scientific impact in the fields of biology and biochemistry (defined by citations per publication) and currently ranks third in the nation in NIH funding among all laboratory-based research institutes. Sanford-Burnham utilizes a unique, collaborative approach to medical research and has established major research programs in cancer, neurodegeneration, diabetes, and infectious, inflammatory, and childhood diseases. The Institute is especially known for its world-class capabilities in stem cell research and drug discovery technologies. Sanford-Burnham is a U.S.-based, non-profit public benefit corporation, with operations in San Diego (La Jolla), California and Orlando (Lake Nona), Florida. For more information, news, and events, please visit us at sanfordburnham.org.

Compound found in rosemary protects against macular degeneration in laboratory model

Contact: Heather Buschman, Ph.D. hbuschman@sanfordburnham.org 858-795-5343 Sanford-Burnham Medical Research Institute

Sanford-Burnham researchers discover that carnosic acid, a component of the herb rosemary, promotes eye health in rodents—providing a possible new approach for treating conditions such as age-related macular degeneration



		IMAGE: Left: This shows control cells exposed to hydrogen peroxide. Right: This shows cells treated with carnosic acid are protected from hydrogen peroxide. Live cells are stained green, dead cells are…Click here for more information.

LA JOLLA, Calif., November 27, 2012 – Herbs widely used throughout history in Asian and early European cultures have received renewed attention by Western medicine in recent years. Scientists are now isolating the active compounds in many medicinal herbs and documenting their antioxidant and anti-inflammatory activities. In a study published in the journal Investigative Ophthalmology & Visual Science, Stuart A. Lipton, M.D., Ph.D. and colleagues at Sanford-Burnham Medical Research Institute (Sanford-Burnham) report that carnosic acid, a component of the herb rosemary, promotes eye health.

Lipton’s team found that carnosic acid protects retinas from degeneration and toxicity in cell culture and in rodent models of light-induced retinal damage. Their findings suggest that carnosic acid may have clinical applications for diseases affecting the outer retina, including age-related macular degeneration, the most common eye disease in the U.S.

Age-related macular degeneration

Age-related macular degeneration likely has many underlying causes. Yet previous studies suggest that the disease might be slowed or improved by chemicals that fight free radicals—reactive compounds related to oxygen and nitrogen that damage membranes and other cell processes.

Lipton’s team first discovered a few years ago that carnosic acid fights off free radical damage in the brain. In their latest study, Lipton and colleagues, including Tayebeh Rezaie, Ph.D. and Takumi Satoh, Ph.D., initially investigated carnosic acid’s protective mechanism in laboratory cultures of retinal cells.

The researchers exposed the cells growing in the dish to hydrogen peroxide in order to induce oxidative stress, a factor thought to contribute to disease progression in eye conditions such as macular degeneration and retinitis pigmentosa. They found that cells treated with carnosic acid triggered antioxidant enzyme production in the cells, which in turn lowered levels of reactive oxygen and nitrogen species (cell-damaging free radicals and peroxides).

Rosemary’s therapeutic potential

Lipton, Rezaie, Satoh and colleagues next tested carnosic acid in an animal model of light-induced damage to photoreceptors—the part of the eye that converts light to electrical signals, enabling visual perception. As compared to the untreated group, rodents pre-treated with carnosic acid retained a thicker outer nuclear layer in the eye, indicating that their photoreceptors were protected. The carnosic acid-treated rodents also exhibited better electroretinogram activity, a measure of healthy photoreceptor function.

What’s next for carnosic acid? “We’re now developing improved derivatives of carnosic acid and related compounds to protect the retina and other brain areas from a number of degenerative conditions, including age-related macular degeneration and various forms of dementia,” said Lipton, director of Sanford-Burnham’s Del E. Webb Neuroscience, Aging, and Stem Cell Research Center and an active clinical neurologist.

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Note to members of the media: Please contact Heather Buschman at hbuschman@sanfordburnham.org to schedule on-site, phone, or Skype interviews with Stuart A. Lipton, M.D., Ph.D. Images are also available upon request.

This research was funded by the U.S. National Institutes of Health: Eunice Kennedy Shriver National Institute of Child Health & Human Development grant P01 HD29587; National Institute of Environmental Health Sciences grant P01 ES016738; National Institute of Neurological Disorders and Stroke grant P30 NS076411; National Eye Institute grant R01 EY05477

The study was co-authored by Tayebeh Rezaie, Sanford-Burnham; Scott R. McKercher, Sanford-Burnham; Kunio Kosaka, Nagase & Co., Ltd.; Masaaki Seki, Sanford-Burnham; Larry Wheeler, Allergan, Inc.; Veena Viswanath, Allergan, Inc.; Teresa Chun, Allergan, Inc.; Rabina Joshi, Sanford-Burnham; Marcos Valencia, Sanford-Burnham; Shunsuke Sasaki, Iwate University; Terumasa Tozawa, Iwate University; Takumi Satoh, Sanford-Burnham and Iwate University; and Stuart A. Lipton, Sanford-Burnham.

About Sanford-Burnham Medical Research Institute

Scripps Research Institute scientists describe elusive replication machinery of flu viruses

Contact: Jann Coury
jcoury@scripps.edu
858-784-8245
Scripps Research Institute



		IMAGE:The new Scripps Research Institute study shows flu virus proteins in the act of self-replication. Shown here is the influenza virus, which encapsidates its RNA genome (green) with a viral… Click here for more information.

LA JOLLA, CA – November 22, 2012 – Scientists at The Scripps Research Institute (TSRI) have made a major advance in understanding how flu viruses replicate within infected cells. The researchers used cutting-edge molecular biology and electron-microscopy techniques to “see” one of influenza’s essential protein complexes in unprecedented detail. The images generated in the study show flu virus proteins in the act of self-replication, highlighting the virus’s vulnerabilities that are sure to be of interest to drug developers.

The report, which appears online in Science Express on November 22, 2012, focuses on influenza’s ribonucleoprotein (RNP). RNPs contain the virus’s genetic material plus the special enzyme that the virus needs to make copies of itself.

“Structural studies in this area had stalled because of the technical obstacles involved, and so this is a welcome advance,” said Ian A. Wilson, the Hansen Professor of Structural Biology at TSRI and senior author of the report with TSRI Professors of Cell Biology Bridget Carragher and Clint Potter. “The data from this study give us a much clearer picture of the flu virus replication machinery.”

Unveiling the Mystery of RNPs

At the core of any influenza virus lie eight RNPs, tiny molecular machines that are vital to the virus’s ability to survive and spread in its hosts. Each RNP contains a segment—usually a single protein-coding gene—of the RNA-based viral genome. This viral RNA segment is coated with protective viral nucleoproteins and has a structure that resembles a twisted loop of chain. The free ends of this twisted loop are held by a flu-virus polymerase enzyme, which handles the two central tasks of viral reproduction: making new viral genomic RNA, and making the RNA gene-transcripts that will become new viral proteins.

Aside from its importance in ordinary infections, the flu polymerase contains some of the key “species barriers” that keep, for example, avian flu viruses from infecting mammals. Mutations at key points on the enzyme have enabled the virus to infect new species in the past. Thus researchers are eager to know the precise details of how the flu polymerase and the rest of the RNP interact.

Getting those details has been a real challenge. One reason is that flu RNPs are complex assemblies that are hard to produce efficiently in the lab. Flu polymerase genes are particularly resistant to being expressed in test cells, and their protein products exist in three separate pieces, or subunits, that have to somehow self-assemble. Until now, the only flu RNPs that have been reproduced in the laboratory are shortened versions whose structures aren’t quite the same as those of native flu RNPs. Researchers also are limited in how much virus they can use for such studies.

The team nevertheless managed to develop a test-cell expression system that produced all of the protein and RNA components needed to make full-length flu RNPs. “We were able to get the cells to assemble these components properly so that we had working, self-replicating RNPs,” said Robert N. Kirchdoerfer, a first author of the study. Kirchdoerfer was a PhD candidate in the Wilson laboratory during the study, and is now a postdoctoral research associate in the laboratory of TSRI Professor Erica Ollmann Saphire.

Kirchdoerfer eventually purified enough of these flu RNPs for electron microscope analysis at TSRI’s Automated Molecular Imaging Group, which is run jointly by Carragher and Potter.

Never Seen Before

The imaging group’s innovations enable researchers to analyze molecular samples more easily, in less time, and often with less starting material. “We were able, for example, to automatically collect data for several days in a row, which is unusual in electron microscopy work,” said Arne Moeller, a postdoctoral research associate at the imaging group who was the other first author of the study.

Electron microscopes make high-resolution images of their tiny targets by hitting them with electrons rather than photons of light. The images revealed numerous well-defined RNP complexes. To Moeller and his colleagues’ surprise, many of these appeared to have new, partial RNPs growing out of them. “They were branching—this was very exciting,” he said.

“Essentially these were snapshots of flu RNPs being replicated, which had never been seen before,” said Kirchdoerfer. These and other data, built up from images of tens of thousands of individual RNPs, allowed the team to put together the most complete model yet for flu-RNP structure and functions. The model includes details of how the viral polymerase binds to its RNA, how it accomplishes the tricky task of viral gene transcription, and how a separate copy of the viral polymerase assists in carrying out RNP replication. “We’re now able to take a lot of what we knew before about flu virus RNP and map it onto specific parts of the RNP structure,” said Kirchdoerfer.

The new flu RNP model highlights some viral weak points. One is a shape-change that a polymerase subunit—which grabs viral RNA and feeds it to the polymerase’s active site on a second subunit—has to undergo during viral gene transcription. Another is key interaction between the polymerase and viral nucleoproteins. Flu RNPs are long and flexible, curving and bending in electron microscope images; and thus the structural model remains only modestly fine-grained. “You wouldn’t be able to design drugs based on this model alone,” said Kirchdoerfer, “but we now have a much better idea of how flu RNPs work, and that does suggest some possibilities for better flu drugs.”

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The study, “Organization of the Influenza Virus Replication Machinery,” was funded in part by grants from the National Institutes of Health (AI058113, GM095573) and the Joint Center for Innovation in Membrane Protein Production for Structure Determination (P50GM073197). TSRI’s Automated Molecular Imaging Group includes the National Resource for Automated Molecular Microscopy, which is supported by the National Institutes of Health’s National Center for Research Resources (2P41RR017573-11) and the National Institute of General Medical Sciences Biomedical Technology Resource Centers (9 P41 GM103310-11).

Macular Degeneration drugs may do More harm than good ( anti-VEGF drugs )

Scripps Research Institute Study Suggests Caution and Further Studies on Drugs Used to Treat Macular Degeneration

LA JOLLA, CA – October 24, 2012 – Millions of people with “wet” macular degeneration are prescribed a class of medication known as anti-VEGF drugs. But now scientists at The Scripps Research Institute (TSRI) have found that a drastic reduction of VEGF activity may do more harm than good.

In the new study, the researchers deleted the gene for the blood-vessel growth factor VEGF, which has been implicated in stimulating abnormal blood vessel growth in a range of cancers and eye diseases, from cells in the retinas of adult mice. The results showed that without VEGF a large subset of light-sensing cells lost their main blood supply and shut down, causing severe vision loss.

“It’s becoming clear that VEGF has a critical function in maintaining the health of the retina, and we need to preserve that critical function when we treat VEGF-related conditions,” said TSRI Professor Martin Friedlander, MD, PhD, senior author of the new study, which appears in the November 2012 issue of the Journal of Clinical Investigation.

Major Target for Drug Developers

VEGF (vascular endothelial growth factor) has long been a major target for drug developers. Tumors often overproduce VEGF to stimulate local blood vessel growth and thus keep their fast-dividing cells well supplied with oxygen and nutrients. Low-oxygen conditions in the eyes of elderly or diabetic individuals also can trigger the overproduction of VEGF, resulting in a vision-destroying bloom of abnormal, leaky retinal blood vessels.

Several anti-VEGF drugs (such as Lucentis^® (ranibizumab), Macugen (pegaptanib), Eylea^® (aflibercept) and Avastin^® (bevacizumab)) are already in use, and dozens more are in clinical trials against cancers and common eye disorders such as wet macular degeneration.

However, to date there have not been extensive studies on the effects of such drugs on the normal role of VEGF, in part because it is hard to generate adult animals that lack the VEGF gene. When the gene is removed from the embryos of mice, in a standard“knockout” experiment, the mice fail to develop normally and die before birth.

New Insights

In the new study, Friedlander laboratory postdoctoral fellows Toshihide Kurihara, MD, PhD, and Peter D. Westenskow, PhD, found a way to delete the major VEGF gene from mice after the animals had grown to adulthood. To determine VEGF’s role in the retina, they confined the gene deletion to the animals’ retinal pigment epithelial cells, which nourish and repair the retina and are a major retinal source of VEGF. The result suggests that VEGF does have a crucial function in the adult retina.

“Only three days after we knocked down the gene, we observed the complete deterioration of the choriocapillaris, a layer of capillaries that is a major supplier of nutrients to the outer retina, the location of the rod and cone photoreceptors,”said Kurihara.

Nearby light-sensing cone cells, which are specialized for detecting color and fine detail in visual images, also rapidly lost their function, causing pronounced vision loss in the mice. Seven months after the knockdown of the VEGF gene, the retinal damage and vision loss were still evident. “The deterioration seems irreversible if VEGF is not present,” said Westenskow.

Rod cells, which support low-light and peripheral vision, were not affected by the VEGF-gene deletion. The researchers note that cone cells may be more vulnerable because they are unusually active metabolically and may be unable to withstand a significant decrease in blood supply. Cone cells also bear receptors for VEGF molecules and thus may require direct VEGF stimulation to remain healthy. In any case, even if only cone cells died and rod cells were spared, a patient would experience severe vision loss. “You’d be defeating your purpose if you dried up the abnormal blood vessel growth but at the same time killed off the cone cells,” said Friedlander.

Paths for Future Research

Whether such side effects are happening with existing anti-VEGF treatments is unclear. While these assessments are possible, but they have been considered prohibitively expensive and invasive.

Friedlander, however, now believes such studies are necessary and plans to conduct such assessments in eye-disorder patients—who typically receive direct injections of anti-VEGF drugs to their eyes—to determine whether the drugs are causing these adverse side effects. He notes that the evaluations may be particularly necessary for a new class of anti-VEGF drugs recently approved for use in the treatment of age-related macular degeneration—drugs that are much more potent and persistent than previous anti-VEGF agents.

Fortunately, anti-VEGF drugs are not the only possible strategy for treating pathological blood vessel growth, as the new study makes clear. VEGF-related tumors and eye conditions also involve the overproduction of low-oxygen signaling proteins known as HIFs. The team found that deleting the genes for these HIFs in retinal cells largely prevents blood vessel overgrowth in a standard mouse model—without affecting the normal-level production of retinal VEGF or causing eye damage.

“In light of the present findings, other strategies for treating these eye conditions could be a possibility,” Friedlander said. “Conceivably, an anti-HIF treatment could also be combined with an anti-VEGF treatment, allowing the dose of the latter to be lowered significantly.”

The Friedlander lab, in collaboration with the laboratories of David Cheresh, PhD, and Michael Sailor, PhD, of the University of California, San Diego, has also been exploring the potential utility of inhibiting microRNAs that regulate angiogenic genes further upstream to VEGF. This work is being supported by a $10 million grant from the National Eye Institute and could lead to the development of antagonists that avoid the off-target effects of VEGF inhibitors.

In addition to Friedlander, Kurihara and Westenskow, other contributors to the study, “Targeted deletion of Vegfa in adult mice induces vision loss,” were Stephen Bravo and Edith Aguilar, both of TSRI. For more information on the paper, see http://www.jci.org/articles/view/65157.

The study was supported in part by grants from the National Eye Institute of the National Institutes of Health (EY-11254, EY-021416), the Lowy Medical Research Institute, the Manpei Suzuki Diabetes Foundation and The Japan Society for the Promotion of Science.

About The Scripps Research Institute

The Scripps Research Institute is one of the world’s largest independent, not-for-profit organizations focusing on research in the biomedical sciences. Over the past decades, Scripps Research has developed a lengthy track record of major contributions to science and health, including laying the foundation for new treatments for cancer, rheumatoid arthritis, hemophilia, and other diseases. The institute employs about 3,000 people on its campuses in La Jolla, CA, and Jupiter, FL, where its renowned scientists—including three Nobel laureates—work toward their next discoveries. The institute’s graduate program, which awards Ph.D. degrees in biology and chemistry, ranks among the top ten of its kind in the nation. For more information, see www.scripps.edu.

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For information: Office of Communications Tel: 858-784-8134 Fax: 858-784-8136 press@scripps.edu

http://www.scripps.edu/news/press/2012/20121024friedlander.html

TIM and TAM: 2 paths used by the Dengue virus to penetrate cells

Contact: Press presse@inserm.fr INSERM (Institut national de la santé et de la recherche médicale)

By demonstrating that it is possible to inhibit the viral infection in vitro by blocking the bonding between the virus and these receptors, the researchers have opened the way to a new antiviral strategy. These works were published on line in the review “Cell Host & Microbe” of October 18, 2012.

The Dengue virus circulates in four different forms (four serotypes). It is transmitted to humans by mosquitoes. It is a major public health problem. Two billion people throughout the world are exposed to the risk of infection and 50 million cases of Dengue fever are recorded by the WHO every year. The infection is often asymptomatic, or resembles influenza symptoms, but its most serious forms can lead to fatal haemorrhagic fevers. At present, there is no preventive vaccine or efficient antiviral treatment for these four Dengue serotypes. So it is of vital importance that we develop new therapeutic strategies.

Ali Amara’s team performed genetic screening in order to identify cell receptors used by the virus to penetrate target cells . The researchers have determined the important function played by the TIM receptors (TIM-1, 3, 4) and TAM receptors (AXL and TYRO-3) in the penetration process of the four Dengue serotypes. Mr. Amara’s team has succeeded in demonstrating that the expression of these 2 receptor families makes cells easier to infect. In addition, the researchers observed that interfering RNA or antibodies that target the TIM and TAM molecules considerably reduced the infection of the cells targeted by the Dengue virus. The TIM and TAM molecules belong to two distinct families of transmembrane receptors that interact either directly (TIM) or indirectly (TAM) with phosphatidylserine, an “eat-me” signal that allows the phagocytosis and the elimination of these apoptopic cells. Unexpectedly, the work of the Inserm researchers discovered that phosphatidylserine is abundantly expressed at the surface of virions and that it was essential that the TIM and TAM receptors recognize the phosphatidylserine to allow infection of target cells.

These results have helped to understand the first key stage in the Dengue virus infectious cycle, by discovering a new method of virus entry that works by mimicking the biological functions involved in the elimination of the apoptotic cells. The discovery of these new receptors has also opened the way for new antiviral strategies aimed at blocking bonding of the Dengue virus with the TIM and TAM molecules.

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This research has been patent-protected by Inserrm Transfert.

For more information

Source

“The TIM and TAM Families of Phosphatidylserine Receptors Mediate Dengue Virus Entry” Laurent Meertens,1,2,3,6 Xavier Carnec,1,2,3,6 Manuel Perera Lecoin,1,2,3,6 Rasika Ramdasi,1,2,3 Florence Guivel-Benhassine,4 Erin Lew,5 Greg Lemke,5 Olivier Schwartz,4 and Ali Amara1,2,3,

1 Unité Inserm 944, Laboratoire de Pathologie et Virologie Moléculaire

2Institut Universitaire d’Hématologie Hôpital Saint-Louis, 1 Avenue Claude Vellefaux. 75010 Paris, France

3University Paris Diderot, Sorbonne Paris Cité, Hôpital St. Louis, 1 Avenue Claude Vellefaux, 75475 Paris, Cedex 10, France

4Unité Virus et Immunité , Institut Pasteur, 28 Rue du Dr. Roux, 75724 Paris, France

5Molecular Neurobiology Laboratory, Immunobiology and Microbial Pathogenesis Laboratory, The Salk Institute, La Jolla, CA 92037, USA

Cell Host and Microbe, 12, issue 4, October 18, 2012 http://www.sciencedirect.com/science/article/pii/S1931312812003046

Stem Cells Not Needed for Cancer

Fully developed neurons can revert to stem cell-like states and give rise to brain tumors.

By Ruth Williams |October 18, 2012

The prevailing view that stem cells are the principle originators of brain cancer may be incorrect, according to a report out today (October 18) in Science.The new study suggests that terminally differentiated brain cells, including neurons, can be reprogrammed by oncogenic factors to become progenitor-like cells that then develop into brain tumors, or gliomas.

“What’s provocative about these experiments is that they challenge the notion that only stem cells can give rise to cancers of the brain,” said David Gutmann, a professor of neurology at Washington University in St Louis, Missouri, who did not participate in the study. “While we were all very excited 10 years ago when the cancer stem cell hypothesis came out, I think it was perhaps wishful thinking for us to believe that that was the only path to cancer.” The researchers were “able to demonstrate that you can get gliomas from these terminally differentiated neurons,” agreed Ronald DePinho, president of the MD Anderson Cancer Center at the University of Texas, Houston. “[The finding] is very exciting and basically teaches us that cells maintain an extraordinary level of plasticity.”

The potential for multiple cell types to give rise to brain cancer may also account for the variety of glioma subclasses observed, Gutmann added.

Inder Verma, a geneticist at the Salk Institute in La Jolla, California made the discovery as part of a larger effort to create mouse models of glioma. The team had injected lentiviral vectors that activated Ras signaling—a pathway that promotes cell growth and division—into the brains of mice that were deficient in the cell cycle protein p53 to induce gliomas.

The cellular origin of these gliomas was unknown, but the researchers assumed the most likely candidates were neural progenitor cells, because such cells are more easily reprogrammable and share many features with cancer cells. In the latest study, however, Verma’s team used an approach to specifically target mature neurons and astrocytes, and found both cell types were able to produce gliomas.

The neuron and astrocyte-derived gliomas expressed high levels of stem and progenitor cell marker proteins. And in vitro studies confirmed that the lentiviral vectors induced differentiated adult brain cells to adopt progenitor like features—similar to those found in neural and induced pluripotent stem cells. Transplanting these reprogrammed cells into receptive mice resulted in tumor growth, confirming the cells were cancerous.

“What we’re saying is, any cell in the brain that gets an oncogenic insult has the ability to dedifferentiate [and form tumors],” said Verma. This might seem a rather bleak outlook, but “by knowing the mechanism, we at least have a handle to start thinking about [treatments],” Verma said.

Of course, just because differentiated neurons can be induced to give rise to tumors experimentally doesn’t mean the process occurs in human patients, Gutmann pointed out. But Verma and colleagues found evidence to suggest that it might. An analysis of the molecular profiles of the tumors derived from adult neurons revealed a striking similarity to that of a particularly aggressive subtype of human glioma. “It is possible that these human tumors might also have originated from neurons,” said Verma.

The finding also suggested that different cells-of-origin give rise to different types of glioma. “It’s like German Americans and Italian Americans,” said Gutmann. “They’re both American citizens but still retain their heritage.” Importantly, he added, those subtle ancestral differences “may make a huge difference in terms of response to therapy and outcome.”

D. Friedmann-Morvinski et al., “Dedifferentiation of neurons and astrocytes by oncogenes can induce gliomas in mice,” Science, doi: 10.1126/science.1226929, 2012

http://www.the-scientist.com/?articles.view/articleNo/32899/title/Stem-Cells-Not-Needed-for-Cancer/

La Jolla Institute unlocks mystery of potentially fatal reaction to smallpox vaccine

Contact: Bonnie Ward contact@liai.org 619-303-3160 La Jolla Institute for Allergy and Immunology

Research team is part of NIH network working toward new smallpox vaccine for eczema sufferers

SAN DIEGO – (May 25, 2009) Researchers from the La Jolla Institute for Allergy & Immunology have pinpointed the cellular defect that increases the likelihood, among eczema sufferers, of developing eczema vaccinatum, a severe and potentially fatal reaction to the smallpox vaccine. The research, conducted in mouse models, was funded under a special research network created by the National Institutes of Health in 2004. The network is working toward the development of a new smallpox vaccine that could be administered to the millions of Americans who suffer from atopic dermatitis, a chronic, itchy skin condition commonly referred to as eczema.

The La Jolla Institute’s Toshiaki and Yuko Kawakami, M.D.s, Ph.D.s., a husband and wife scientific team, led the research group which found that activity levels of Natural Killer (NK) cells played a pivotal role in the development of eczema vaccinatum in the mice. The activity of the NK cells, which are disease fighting cells of the immune system, was significantly lower in the mice that developed eczema vaccinatum than in normal mice that also received the smallpox vaccine. This knowledge opens the door to one day developing therapies that could potentially boost NK cell activity in eczema sufferers.

“Since atopic dermatitis affects as many as 17 percent of children in the U. S. and since eczema vaccinatum carries a fatality rate of 5-10 percent, therapies that prevent or treat eczema vaccinatum successfully are crucial should the need for mass vaccination against smallpox arise in response to bioterrorism,” said Harvard pediatrics professor Raif S. Geha, M.D., chief of immunology at Boston Children’s Hospital and a principal investigator in the NIH funded network investigating eczema vaccinatum. “The discovery of the Kawakami team, who are participants in the NIH network, is an important step towards this goal.”

People with active atopic dermatitis (eczema), or who have outgrown atopic dermatitis, and the people they live with currently cannot receive smallpox vaccinations because of the risk of eczema vaccinatum. While uncommon, eczema vaccinatum can develop when atopic dermatitis patients are given the smallpox vaccine or come into close personal contact with people who recently received the vaccine. It is estimated that a significant portion of the U.S. population is currently not eligible for smallpox vaccination.

“This discovery answers an important question that has long eluded the scientific community, “why people with atopic dermatitis were susceptible to developing eczema vaccinatum upon receiving the smallpox vaccine, while the general population was not,” said Mitchell Kronenberg, the La Jolla Institute’s president & scientific director. “It marks a significant advance toward the goal of ensuring that everyone can one day be protected against the smallpox virus.”

The finding was published today in the online version of the Journal of Experimental Medicine in a paper entitled, “Inhibition of NK cell activity by IL-17 allows vaccinia virus to induce severe skin lesions in a mouse model of eczema vaccinatum.” La Jolla Institute scientist Shane Crotty, Ph.D., also contributed to the study.

Regarded as the deadliest disease ever known to man, smallpox was officially eradicated worldwide in 1980 and routine vaccinations against the disease ended in the U.S in 1972. However, bioterrorism concerns have arisen over recent years regarding the deliberate distribution of the smallpox virus, which might make smallpox vaccinations once again necessary. Such concerns led to the creation of the Atopic Dermatitis and Vaccinia Network (ADVN), a consortium of medical and research institutions nationwide developed by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. The network, which provided grant funding for the Kawakami’s studies under NIH contact N01-AI40030C, was launched in 2004 with the goal of developing a new smallpox vaccine that would be safe for atopic dermatitis sufferers. It includes three consortiums, involving data, clinical testing and animal studies, of which Drs. Kawakami and the La Jolla Institute are members.

The Animal Studies Consortium was created to establish animal models of atopic dermatitis and investigate their immune responses to vaccinia — the virus used in smallpox vaccine. Drs. Kawakami were invited to join the consortium due to their creation of a new, more effective atopic dermatitis mouse model in 2004.

In their study, Drs. Kawakami showed that eczema-infected mice had higher levels of IL-17 cells, which are known to inhibit NK cell activity. “This higher level of IL-17 cells slowed down the ability of the NK cells to kill the vaccinia virus,” said Yuko Kawakami, noting people with atopic dermatitis are also known to have higher numbers of IL-17 producing cells. “This led to the development of eczema vaccinatum when these mice received the smallpox vaccine.”

Drs. Kawakami tested their theory by stimulating more NK cell activity in the eczema-infected mice. The higher activity led to the elimination of the eczema vaccinatum infection. “We are very excited by these findings, ” said Toshiaki Kawakami. “Developing a safer smallpox vaccine is the most important thing in this field.”

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About La Jolla Institute

Founded in 1988, the La Jolla Institute for Allergy & Immunology is a nonprofit medical research center dedicated to increasing knowledge and improving human health through studies of the immune system. Scientists at the institute carry out research searching for cures for cancer, allergy and asthma, infectious diseases, and autoimmune diseases such as diabetes, inflammatory bowel disease and arthritis. La Jolla Institute’s research staff includes more than 100 Ph.Ds and M.D.s.

Reposted at request

How antipsychotic medications cause metabolic side effects such as obesity and diabetes

LA JOLLA, Calif. — In 2008, roughly 14.3 million Americans were taking antipsychotics—typically prescribed for bipolar disorder, schizophrenia, or a number of other behavioral disorders—making them among the most prescribed drugs in the U.S. Almost all of these medications are known to cause the metabolic side effects of obesity and diabetes, leaving patients with a difficult choice between improving their mental health and damaging their physical health. In a paper published January 31 in the journal Molecular Psychiatry, researchers at Sanford-Burnham Medical Research Institute (Sanford-Burnham) reveal how antipsychotic drugs interfere with normal metabolism by activating a protein called SMAD3, an important part of the transforming growth factor beta (TGFbeta) pathway.

The TGFbeta pathway is a cellular mechanism that regulates many biological processes, including cell growth, inflammation, and insulin signaling. In this study, all antipsychotics that cause metabolic side effects activated SMAD3, while antipsychotics free from these side effects did not. What’s more, SMAD3 activation by antipsychotics was completely independent from their neurological effects, raising the possibility that antipsychotics could be designed that retain beneficial therapeutic effects in the brain, but lack the negative metabolic side effects.

“We now believe that many antipsychotics cause obesity and diabetes because they trigger the TGFbeta pathway. Of all the drugs we tested, the only two that didn’t activate the pathway were the ones that are known not to cause metabolic side effects,” said Fred Levine, M.D., Ph.D., director of the Sanford Children’s Health Research Center at Sanford-Burnham and senior author of the study.

In a previous study aimed at developing new insights into diabetes, Dr. Levine and his team used Sanford-Burnham’s high-throughput screening capabilities to search a collection of known drugs for those that alter the body’s ability to generate insulin, the pancreatic hormone that helps regulate glucose. That’s when they first noticed that many antipsychotics alter the activity of the insulin gene. In this current study, the researchers set out to connect the dots between antipsychotics and insulin. In doing so, experiments in laboratory cell-lines showed that antipsychotics known to cause metabolic side effects also activated the TGFbeta pathway—a mechanism that controls many cellular functions, including the production of insulin—while the drugs without these side effects did not.

Wondering whether their initial laboratory observations were relevant to the human experience, the researchers reanalyzed previously published gene expression patterns in brain tissue from schizophrenic patients treated with antipsychotics. What they found supported their earlier findings—TGFbeta signaling was activated only in those patients receiving antipsychotic treatment. Looking further, they found that the extent to which each antipsychotic drug activated the TGFbeta pathway in human brains correlated very closely with the extent to which those same drugs activated SMAD3 and affected the insulin promoter in their cell culture experiments.

The TGFbeta pathway also plays an important role in metabolic disease in people who don’t take antipsychotic medications. “It’s known that people who have elevated TGFbeta levels are more prone to diabetes. So having a dysregulated TGFbeta pathway—whether caused by antipsychotics or through some other mechanism—is clearly a very bad thing,” said Dr. Levine. “The fact that antipsychotics activate this pathway should be a big concern to pharmaceutical companies. We hope this new information will lead to the development of improved drugs.”

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This study was funded by a gift from Mr. T. Denny Sanford to the Sanford Children’s Health Research Center at Sanford-Burnham. Co-authors include Thomas Cohen, Sanford-Burnham and University of California, San Diego; S. Sundaresh, NextBio; and Fred Levine, Sanford-Burnham.

About Sanford-Burnham Medical Research Institute

Sanford-Burnham utilizes a unique, collaborative approach to medical research and has established major research programs in cancer, neurodegeneration, diabetes, and infectious, inflammatory, and childhood diseases. The Institute is especially known for its world-class capabilities in stem cell research and drug discovery technologies. Sanford-Burnham is a U.S.-based, non-profit public benefit corporation, with operations in San Diego (La Jolla), Santa Barbara, and Orlando (Lake Nona). For more information, please visit our website (http://www.sanfordburnham.org) or blog (http://beaker.sanfordburnham.org). You can also receive updates by following us on Facebook and Twitter.