RNA dynamics deconstructed

Technique offers detailed view of how RNA levels change

RNA plays a critical role in directing the creation of proteins, but there is more to the life of an RNA molecule than simply carrying DNA's message. One can imagine that an RNA molecule is born, matures, and eventually, meets its demise. Researchers at the Broad have developed an approach that offers many windows into the lifecycle of these essential molecules and will enable other scientists to investigate what happens when something in a cell goes wrong. They describe their approach, which offers high resolution and a comprehensive scope, in a Nature Biotechnology article published online on April 24.

"People are discovering more and more how the RNA lifecycle is at the heart of problems we see in disease, but we actually understand a lot less about it than we understand about many other cellular processes," said Aviv Regev, a core faculty member of the Broad Institute and a co-senior author on the paper.

Regev and her colleagues have developed a method that allows them to tease apart the different stages of this lifecycle by measuring how much messenger RNA is produced and how much is degraded. The balance of these two processes contributes to the changes seen in RNA levels in a cell over time, much the way that birth and death rates contribute to a country's total population.

RNA levels are dynamic – they change in response to certain stimuli. For this study, the researchers examined dendritic cells, which are involved in the body's immune response, as a model. They exposed these cells to a stimulus that resembled a pathogen and then looked at RNA changes before and after exposure.

"We wanted to understand how cells regulate RNA levels, and if regulation happens at the step of producing the molecule, degrading the molecule, or processing it," said Michal Rabani, first author of the paper and an MIT graduate student at the Broad. "Each of these steps can affect the level of active RNA molecules in cells. If you want to understand what happens when things go wrong, you have to understand how things work when they work as they should."

The researchers' approach allows them to look at a specific cell type and see changes in the expression of all genes. This combination of breadth and specificity offers a systematic view of how RNA changes over time. "If we want to look at specific neurons in the brain or a specific cell that's lying between other kinds of cells in the lung, this technique allows us to zoom in on one process in one cell among a billion other cells. This is the case in many diseases, a short circuit in one specific cell type, and now we have a great tool to find it," said Ido Amit, a co-senior author of the paper and a scientist at the Broad.

The scientists harnessed an existing technique to trace the fate of newly produced RNA and paired it with a new sequencing-based technology that counts molecules of mRNA. The results also gave the researchers a view of some of the in-between steps, during which mRNA is edited or processed – an unexpected but serendipitous finding. "That's the beauty of sequencing: it has a very extensive view so it shows you things you didn't expect to see," said Regev.

A key aspect of the approach is that the researchers were able to take "snapshots" of RNA levels over very short time intervals. Strung together, these snapshots reveal not only how the amount of RNA changes, but also the short-lived, intermediate phases of the RNA lifecycle that are otherwise impossible to detect. "This allows us many windows into the world of RNA," said Amit.

One critical application of the new method is in following up on leads from disease studies, such as mutated genes in cancer or other diseases that impact the RNA lifecycle. "In the past, you would know that there's a mutation and there's even a suspicion of what the gene does, but it would have been extraordinarily hard to see the effect of the mutation on these types of processes in the cell," said Regev, who is also an assistant professor at MIT and an early career scientist at the Howard Hughes Medical Institute. The researchers hope that their newly developed technique will enable others to gain deep insights into how gene mutations disrupt RNA levels, and in turn, what proteins are made.

"We're decomposing these RNA levels, breaking them down into each separate step, so that we can understand what happens at each of these steps and how they interact with each other to produce the final read out," said Rabani. "It's a very complex system, but understanding it could eventually help us understand what goes wrong when things don't work."

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This work was supported by the Richard Merkin Foundation for Stem Cell Research at the Broad Institute through a gift that Regev describes as essential for the project's success.

Paper cited:

Rabani M et al. Metabolic labeling of RNA uncovers principles of RNA production and degradation dynamics in mammalian cells. Nature Biotechnology. April 24, 2011. DOI: 10.1038/nbt.1861

About the Broad Institute of Harvard and MIT

The Eli and Edythe L. Broad Institute of Harvard and MIT was launched in 2004 to empower this generation of creative scientists to transform medicine. The Broad Institute seeks to describe all the molecular components of life and their connections; discover the molecular basis of major human diseases; develop effective new approaches to diagnostics and therapeutics; and disseminate discoveries, tools, methods and data openly to the entire scientific community.

Founded by MIT, Harvard and its affiliated hospitals, and the visionary Los Angeles philanthropists Eli and Edythe L. Broad, the Broad Institute includes faculty, professional staff and students from throughout the MIT and Harvard biomedical research communities and beyond, with collaborations spanning over a hundred private and public institutions in more than 40 countries worldwide. For further information about the Broad Institute, go to http://www.broadinstitute.org.

About the Richard Merkin Foundation for Stem Cell Research at the Broad Institute

The Richard Merkin Foundation for Stem Cell Research at the Broad Institute seeks to fund Broad Institute-affiliated scientists to develop a novel and comprehensive "toolbox" of experimental methods and computational algorithms and to apply those tools to understand cellular circuitry in stem cells, with the goal of being able to manipulate those circuits for both biological knowledge and medical applications.

Contact: Nicole Davis
ndavis@broadinstitute.org
617-714-7152
Broad Institute of MIT and Harvard

Medical College of Georgia : Blood pressure response to daily stress provides clues for better hypertension treatment

How the body regulates blood pressure in response to daily stress is the focus of a study geared toward helping people whose pressure is out of control.

“Research shows that two-thirds of patients’ high blood pressure is not controlled despite the best efforts of their doctors. That is terrible,” says Dr. Gregory Harshfield, director of the Georgia Prevention Institute at the Medical College of Georgia.

“We are trying to identify the mechanisms through which blood pressure is regulated under normal everyday conditions – which is what stress is – and take that information back to the clinic to better determine what sort of therapy is going to be most effective at treating your blood pressure or your grandfather’s.”

More than a dozen researchers have teamed up to do parallel studies in animal models and young adults to learn more about what factors like genes, stress and obesity contribute, their synergy and novel ways to control them.

“This research will give us information that allows us to identify what treatment is going to be effective in what individual by genotype, by obesity and other factors. What kind of treatment is going to be effective at keeping an individual’s blood pressure down or maybe preventing it from ever getting high,” says Dr. Harshfield, principal investigator on the $10.6 million Program Project grant renewal from the National Institutes of Health’s National Heart, Lung and Blood Institute. 72 million Americans – 1 in 3 – are hypertensive, according to the NHLBI.

Studies will explore fundamentals such as why about 30 percent of young healthy blacks and 15 percent of whites can’t effectively excrete sodium, a problem that raises blood pressure by increasing the body’s fluid volume. “We think there is a defect in their kidneys, in the normal mechanisms that allow them to excrete salt,” said Dr. David Pollock, renal physiologist at MCG’s Vascular Biology Center and a program project leader. “When blood pressure goes up due to stress, their kidneys ought to get rid of more salt so their blood pressure will come down, and they don’t.”

Dr. Harshfield’s studies identified this impaired stress-induced sodium natriuresis. He believes it’s also a primary reason blood pressure remains elevated at night in some blacks, rather than dipping as it should, which keeps stressing the cardiovascular system.

Using a rat bred to be salt-sensitive, the researchers are working to identify more about the genetics of impaired sodium-handling. “We have animal model data that says the endothelin system normally functions to help your kidneys get rid of salt,” says Dr. Pollock. His studies have shown the kidney’s endothelin B receptor plays a critical role in promoting excretion of acute and chronic salt loads by activating the precursor to nitric oxide, a powerful dilator of blood vessels. In the new studies, he’ll control the rats’ diet and see whether stress slows down sodium excretion. Preliminary evidence suggests it does. He’ll also give the rats an endothelin antagonist, which blocks this hormone, and see if sodium excretion improves. He’ll also see how a high-fat diet and obesity alter the equation.

Meanwhile, for about a week, young study participants with impaired sodium excretion will take a drug to block the powerful blood vessel constrictor, angiotensin. “From our point of view, angiotensin promotes sodium retention directly and it also increases aldosterone, another hormone which promotes sodium retention,” Dr. Harshfield says. The researchers chose to study endothelin and angiotensin because they believe they work together. To explore the genetics, they’ll also look at young adults with a different version of the angiotensin receptor gene that they believe exacerbates sodium-handling problems. MCG researchers identified this genetic variation in people who retain sodium; blocking the receptor gene will provide more evidence about the importance of angiotensin, says Dr. Harshfield.

They’ll mimic the way many people work – an hour of stress, a few minutes of relief, then back to stress – by getting the young people to play competitive video games, then measuring how gene blockers affect sodium excretion. “Ultimately, you want to know how to treat people with this variation,” Dr. Harshfield says. “There is still a need to figure out why some people respond to some therapies and other don’t,” adds Dr. Pollock. “That is not our specific question but these studies will help address that. We have to identify what is it about different individuals that make them react more to stress, makes them retain more salt.”

Obesity, which is associated with increased blood pressure reactivity, is probably a differentiator, Dr. Pollock says. Fat cells actually secrete angiotensin, which gets into the bloodstream. “We are arguing in our study that you might want to treat patients differently depending on whether or not they are obese. The angiotensin receptor blocker may be more effective in obese individuals who have angiotensin falling out into their bloodstream,” says Dr. Harshfield. Consequently they’ll also compare the effectiveness of the blocker in obese and normal-weight individuals with impaired sodium excretion.

Another project is exploring the role of oxidative stress, or reactive oxygen species, in raising blood pressure. In an animal model genetically predisposed to salt-sensitive hypertension, Dr. Jennifer Pollock, biochemist in MCG’s Vascular Biology Center and a program project leader, has shown a prolonged recovery to normal blood pressure following stress. She’s also found oxidative stress levels go up with stress. Oxidative stress, or reactive oxygen species, helps make normal chemical reactions in the body but, in excess, can cause havoc. In fact, when she gives the rats an antioxidant before a stressor, blood pressure doesn’t rise as high and recovery is more normal. “We also found out that endothelin actually is the stimulus for increasing reactive oxygen species,” Dr. Jennifer Pollock says. “When we gave the rats a specific type of endothelin blocker, that also blocked the increase in oxidative stress, blocked the blood pressure increase and improved recovery.”

Now they want to know the specific sources of the reactive oxygen species. Earlier work by Dr. Frank Treiber, MCG vice president for research and principal investigator on the original Program Project grant in 2002, has shown increased blood pressure reactivity in children who are obese and/or have low socioeconomic status.

Looking at how obesity weighs in, Dr. Jennifer Pollock also is putting the rats on high-fat diets. It’s known these rats become hypertensive on a high-salt or high-fat diet and they’ve found that, as with people, fat also increases blood pressure reactivity. Now she is going to find out how.

Another animal model is providing insight into the impact of early life stressors or low socioeconomic status on cardiovascular disease. Research again found that, as with people, these animals have normal blood pressure as pups. But as stressed adult rats, they have higher pressure increases and a delayed recovery unless they are missing an endothelin receptor gene. “It cures it,” says Dr. Jennifer Pollock. “This early life stressor is being mediated through the endothelin pathway.” Her postdoctoral fellow, Dr. Analia Loria, found these early life stressor models also have more constrictive blood vessels because they are more sensitive to angiotensin. New studies will further test the endothelin connection and see if a high-fat diet makes things worse by increasing oxidative stress.

Wildlife biologists have found naturally occurring models. Rat pups whose mother builds a nest far from a food source and so must be gone foraging several hours each day, are more anxious. Neurobiologists have shown animals separated from their moms for long periods can’t run through mazes well and tend to back off in competition for food, Dr. Jennifer Pollock says. “We took that to mean their blood pressure could also be hyper reactive. Sure enough, that is what we found.”

“This has a lot of implications for earlier detection of risk-increasing environmental exposures and what you can do about it,” says Dr. Treiber, a clinical child psychologist and program project leader. “If you can’t alter the environment that quickly in life, you know now where they are headed and maybe you can preempt it pharmacogenetically.”

In the diverse group of some 600 young people he’s been following for 17 years, Dr. Treiber has found that, as with the general population, some already are obese and/or hypertensive at the average age of 25. He’ll continue to follow and annually assess them over the next five years in an effort to better understand how stress contributes to hypertension. “What we are doing is looking at chronic environmental stress in combination with some bad candidate genes that are stress activated,” says Dr. Treiber. He’s thinking that, as with rats, genetic predisposition and stress can doom people with normal pressures to hypertension. They’ll look at blood pressure reactivity, recovery, sodium secretion, measure the footprints left by oxidative stress and the levels of the stress hormone cortisol. They’ll look at early indicators of cardiovascular disease, such as enlargement of the pumping chamber of the heart and signs of carotid artery disease. “If you have a tendency to have high blood pressure or if you are obese, we can see the inner layer of the carotid getting thicker than normal people your age,” says Dr. Gaston Kapuku, cardiologist and cardiovascular researcher at the Georgia Prevention Institute and a project core leader.

America’s current obesity and type 2 diabetes epidemic also has them looking at insulin, glucose and cholesterol levels and whether fat exacerbates all the factors they are following, which they believe it does.

One reason the Georgia Prevention Institute was founded was to identify risk factors for cardiovascular disease, says Dr. Harshfield. In his 10 years at the institute, the agenda has shifted from looking at precursor development of adult hypertension to identifying mechanisms causing pediatric hypertension, a disease that didn’t exist when most hypertension textbooks were written, he says.

“Our ultimate goal, of course, is prevention,” he says. “But when we can’t do that, we want to give physicians ways to determine precisely the cause or causes of your hypertension and optimal ways to target your disease.”

The MCG Department of Biostatistics, chaired by Dr. Varghese George, is designing the studies for the Program Project grant to ensure scientifically validity and managing data for all the program projects.

Harvard Medical School Being a control freak aids dividing cells

Micromanagers may generate resentment in an office setting, but they get results in your body. New data indicate that a dividing cell takes micromanagement to the extreme, tagging more than 14,000 different sites on its proteins with phosphate, a molecule that typically serves as a signal for a variety of biological processes.

This preponderance of signals suggests that the cell may become a control freak during the division process, regulating each of its parts, no matter how obscure. It may take extreme measures to ensure that each "daughter" receives a full complement of cellular material. The new data—published online the week of July 28 in PNAS—open unexplored frontiers to developmental biologists, cancer researchers, and others who study cell growth and proliferation.

"There's a massive wave of phosphorylation in dividing cells, much bigger than anyone expected," says HMS associate professor of cell biology Steven Gygi, who is corresponding author on the study. "This discovery implies that we've severely underestimated the scope of regulation in cell division for decades, which has implications for our understanding of a wide-range of diseases and developmental defects linked to the cell cycle, from cancer to holes in the heart."

Traditionally, researchers probed cell division by zooming in on a particular gene or protein and tracing its interactions. But Gygi took a different approach. A leader in the emerging field of "proteomics," which involves looking at thousands of proteins at once, his team used an instrument called a mass spectrometer to essentially take a wide-angle shot of dividing cells, capturing information that narrow studies missed. The panoramic view revealed a surprising level of signaling activity throughout the cell.

"An enormous number of proteins—more than 1,000—became highly phosphorylated during cell division, some more than 10 times," says postdoctoral researcher Noah Dephoure, who ran the experiment.

In collaboration with Chunshui Zhou, a researcher in HMS professor of genetics Stephen Elledge's lab, Dephoure worked with human cells, dividing them into two dishes. (The cells used are HeLa cells, which, while derived from a tumor, are used for many experiments because they thrive in culture. It's possible that some of the signaling events reported here are unique to these cells.) The first dish received nutrients with "heavy" carbon atoms—more massive than their "light" counterparts, which are abundant in nature. The second dish received normal nutrients, plus a toxic chemical to freeze the cells mid-division.

Dephoure and Zhou mixed all the cells together, killed them, chopped their constituent proteins—which were preserved—into small pieces called peptides, and fed these into a mass spectrometer. The instrument distinguished between otherwise identical peptides, based on the presence of "heavy" or "light" atoms, generating a ratio for each peptide. Dephoure paid particular attention to the ratios for peptides containing phosphate groups and uncovered major differences between the two populations of cells.

The dividing cells harbored a staggering number of regulated phosphate groups in unexpected places.

Gygi hypothesizes that the cell uses phosphorylation to break down every last protein complex before dividing. "Maybe the cell does something akin to putting Humpty Dumpty back together again at the end," he says.

"The massive number of phosphorylation changes in cell division strongly suggests that it involves a massive reorganization of the cell," adds HMS Department of Systems Biology chair Marc Kirschner, who was not involved in the study.

"Or the cell might phosphorylate everything to ensure that it hits a few key targets critical for proper division," says Dephoure. Under this scenario, extraneous phosphorylation may cloud the picture.

Armed with the team's list of proteins and phosphorylation sites, labs can conduct additional experiments to resolve this debate. They can investigate particular phosphorylation events and determine which ones contribute to successful regulation of cell division. Some may present therapeutic targets for patients with cell cycle diseases such as cancer.

"This study demonstrates how much a broad systematic approach to protein modification can facilitate experiments in the cell cycle field," says Kirschner. "We will be reaping results from this study for years ahead."

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This research is funded by the National Institutes of Health, the Spanish Ministry of Education and Science, and Howard Hughes Medical Institute.

Fred Hutchinson Cancer Research Center : A new biomarker for early cancer detection? Research reveals that 'microRNA' may fit the bill

Scientists at Fred Hutchinson Cancer Research Center have discovered that microRNAs – molecular workhorses that regulate gene expression – are released by cancer cells and circulate in the blood, which gives them the potential to become a new class of biomarkers to detect cancer at its earliest stages. Muneesh Tewari, M.D., Ph.D., and colleagues describe their findings in the July 28 issue of the Proceedings of the National Academy of Sciences.

MicroRNAs, which act as brakes on different parts of a cell, keeping genes in check, have some advantages over protein-based early-detection systems, including that they can be detected potentially in smaller quantities and that the technology exists to rapidly develop microRNA-based early-detection tests, said Tewari, an assistant member in the Hutchinson Center's Human Biology and Clinical Research divisions. His work is focused on understanding why the brakes fail – allowing unchecked cell growth – in prostate and ovarian cancer.

"Current technology for developing tests to measure microRNAs in clinical samples is quite advanced, whereas the bottleneck for developing protein-based biomarkers is the slow process of generating assays for measuring specific proteins," he said.

The next steps, now that a proof of principle has been established, are to identify specific microRNAs that can signal the presence of a variety of solid-tumor cancers at an early stage, and to further develop the technology to detect the microRNAs in minute quantities.

For the study, Tewari and colleagues tested blood from mice and humans with advanced prostate cancers, as well as that from healthy controls. They measured microRNAs made by the tumors in both cases and controls, and they could distinguish which individuals had cancer based on blood microRNA measurement.

"This research shows that microRNAs, which weren't previously thought of as markers of cancer in the blood, are a worthwhile class of molecules to study for the purpose of early cancer detection," Tewari said.

The research that led to the surprising finding of microRNAs in plasma and serum resulted from a combination of observations and a hunch, he said.

MicroRNAs play a key role in a wide range of normal cell processes, including embryonic development and cell differentiation. The tiny regulatory molecules modulate the activity of specific messenger-RNA targets, which in turn give rise to proteins. Humans have 30,000 genes that can make messenger RNAs. There are more than 500 known microRNAs encoded by the human genome and each is thought to target up to hundreds of messenger RNAs.

That microRNAs existed in humans is in itself a recent discovery. Tewari's group initially was studying their role in cancer development and maintenance because microRNAs are often dysregulated in cancer. During the course of those experiments, the scientists found that microRNAs circulate outside of cells and are remarkably stable.

"We were surprised to discover that there are microRNAs in plasma and serum that are not associated with cells and that are not being degraded by enzymes in the blood that would degrade regular RNA," Tewari said. It isn't fully known how the microRNAs are protected from degradation or how they get into the blood.

This in turn led the researchers into a new direction of determining whether cancer-associated microRNAs could be found. Earlier studies in model organisms such as worms and flies showed that some microRNAs have specific expression in certain kinds of cells and not anywhere else.

The paper details the step-by-step approach that led to discovering microRNAs in plasma and serum components of blood, that microRNAs remain stable even after incubation at room temperature for 24 hours and after eight freeze/thaw cycles, and finally that tumor-derived microRNAs enter the circulation at levels sufficient to be measured as biomarkers for cancer.

"The results presented here establish the foundation and rationale to motivate future global investigations of microRNAs as circulating cancer biomarkers for a variety of common cancers," the authors wrote.

The availability of existing, powerful tools to characterize and measure microRNAs, such as polymerase-chain reaction technology for DNA amplification, "suggests that the discovery-validation pipeline for microRNA biomarkers will be more efficient than traditional proteomic biomarker discovery-validation pipelines, which typically encounter bottlenecks at the point of antibody and quantitative assay development for validation of biomarker candidates," the authors wrote.

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In addition to those from the Hutchinson Center, scientists from the Institute for Systems Biology in Seattle, the Department of Urology at the University of Washington School of Medicine and the Department of Veterans Affairs Puget Sound Health Care System contributed to the research. The National Cancer Institute, the Pacific Ovarian Cancer Research Consortium Specialized Program of Research Excellence, the Pacific Northwest Prostate Specialized Program of Research Excellence, the Core Center of Excellence in Hematology and the Paul Allen Foundation for Medical Research funded the research.

Note to editors/reporters: Contact Dean Forbes at Fred Hutchinson Cancer Research Center to schedule interviews with Dr. Tewari and to obtain an embargoed proof copy of the paper "Circulating microRNAs as stable blood-based markers for cancer detection."

At Fred Hutchinson Cancer Research Center, our interdisciplinary teams of world-renowned scientists and humanitarians work together to prevent, diagnose and treat cancer, HIV/AIDS and other diseases. Our researchers, including three Nobel laureates, bring a relentless pursuit and passion for health, knowledge and hope to their work and to the world. For more information, please visit fhcrc.org.

Society for Experimental Biology and Medicine : Imiquimod, an immune response modifier, is dependent on the OGF-OGFr signaling pathway

Researchers at The Pennsylvania State University College of Medicine, Hershey, Pennsylvania have discovered that the efficacy of imiquimod, a clinically important immune response modifier with potent antiviral and antitumor activity, is dependent on the Opioid Growth Factor (OGF)-OGF receptor (OGFr) axis for its action. This discovery, reported in the August 08 issue of Experimental Biology and Medicine, provides new insights into a widely used drug that may lead to development of new agents that will enhance effectiveness and attenuate side-effects.

Imiquimod and resiquimod are imidazoquinoline compounds. Imiquimod (Aldara, R-837, S26308), the best characterized and most widely used, is highly efficacious in the treatment of external genital and anal warts, basal cell carcinoma, actinic keratoses, Kaposi's sarcoma, chronic hepatitis C infection, and intraepithelial carcinoma. Therefore, the underlying mechanism of imiquimod action is of clinical importance. Imiquimod has been reported to be a toll-like receptor-7 agonist, and its anti-tumor effect exerted by modification of the immune response and stimulation of apoptosis. The mechanism of imiquimod on cell proliferation is unclear.

The research team, led by Dr. Ian S. Zagon, Distinguished University Professor, and Dr. Patricia J. McLaughlin, Professor, along with a pre-doctoral student Renee N. Donahue, in the Department of Neural & Behavioral Sciences and collaborator Moshe Rogosnitzky of MedInsight explored mechanisms responsible for the remarkable clinical action of this class of drugs. Specifically, using tissue culture models, the investigators found that imidazoquinolines upregulate OGFr which in turn stimulates the interaction of the OGF-OGFr axis. This native, tonically active inhibitory pathway is known to regulate cell proliferation by modulating cyclin dependent kinase inhibitors, resulting in a retardation of cells at the G1-S interface of the cell cycle. Neutralization of OGF or knockdown of OGFr by siRNA technology eliminated the inhibitory effects of imidazoquinolines on cell replication. "Thus our data," Dr. Zagon said, "brings a paradigm shift to our thinking about a drug widely used in the clinics. Rather than imiquimod activity being mediated by induction of various cytokines, including interferon (IFN)-α, IFN-γ, tumor necrosis factor-α (TNFα) interleukin (IL)-1α, and IL-12 as currently thought, an entirely new pathway - native to body chemistry - has been discovered to regulate cell proliferation by imidazoquinolines." Co-author, Moshe Rogosnitzky adds: "The elucidation of imiquimod's immune-independent mechanism of action in cancer also creates exciting new therapeutic possibilities for a number of non-cancer conditions, and these are now being further explored. Such studies could lead to new off-label applications for imiquimod as well as development of imiquimod analogues and unique combination therapies." Dr. Steven R. Goodman, Editor-in-Chief of Experimental Biology and Medicine stated "Through decades of elegant and ground-breaking work, Zagon and colleagues have identified the role of met-enkephalin (the opioid growth factor –OGF) and the OGF receptor in regulating cell proliferation. The current study demonstrates that the mechanism of imidazoquinoline activity is via OGF and OGFr which will have a profound impact on its use as a therapeutic for cancer and many other non-cancerous disorders."

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Experimental Biology and Medicine is a journal dedicated to the publication of multidisciplinary and interdisciplinary research in the biomedical sciences. The journal was first established in 1903.

Experimental Biology and Medicine is the journal of the Society of Experimental Biology and Medicine. To learn about the benefits of society membership visit www.sebm.org. If you are interested in publishing in the journal please visit www.ebmonline.org.

University of Washington : Scientists break record by finding northernmost hydrothermal vent field

The top three feet of a chimney nearly 40 feet tall are visible as the arm of a remotely operated vehicle reaches in to sample fluids. The vent is part...

Well inside the Arctic Circle, scientists have found black smoker vents farther north than anyone has ever seen before. The cluster of five vents – one towering nearly four stories in height – are venting water as hot as 570 F.

Dissolved sulfide minerals that solidify when vent water hits the icy cold of the deep sea have, over the years, accumulated around the vent field in what is one of the most massive hydrothermal sulfide deposits ever found on the seafloor, according to Marvin Lilley, a University of Washington oceanographer. He's a member of an expedition led by Rolf Pedersen, a geologist with the University of Bergen's Centre for Geobiology, aboard the research vessel G.O. Sars.

The vents are located at 73 degrees north on the Mid-Atlantic Ridge between Greenland and Norway. That's more than 120 miles from the previous northernmost vents found during a 2005 expedition, also led by Pedersen. Other scientists have detected plumes of water from hydrothermal vents even farther north but have been unable to find the vent fields on the seafloor to image and sample them.

In recent years scientists have been interested in knowing how far north vigorous venting extends. That's because the ridges where such fields form are so stable up north, usually subject only to what scientists term "ultra-slow" spreading. That's where tectonic forces are pulling the seafloor apart at a rate as little as 6/10th of an inch in a year. This compares to lower latitudes where spreading can be up to eight times that amount, and fields of hydrothermal vents are much more common.

"We hadn't expected a lot of active venting on ultra-slow spreading ridges," Lilley said.

The active chimneys in the new field are mostly black and covered with white mats of bacteria feasting on the minerals emitted by the vents. Older chimneys are mottled red as a result of iron oxidization. All are the result of seawater seeping into the seafloor, coming near fiery magma and picking up heat and minerals until the water vents back into the ocean. The same process created the huge mound of sulfide minerals on which the vents sit. That deposit is about 825 feet in diameter at its base and about 300 feet across on the top and might turn out to be the largest such deposit seen on the seafloor, Lilley said. Additional mapping is needed.

"Given the massive sulfide deposit, the vent field must surely have been active for many thousands of years," he said.

The field has been named Loki's Castle partly because the small chimneys at the site looked like a fantasy castle to the scientists. The Loki part refers to a Norwegian god renowned for trickery. A University of Bergen press release about the discovery said Loki "was an appropriate name for a field that was so difficult to locate."

Indeed this summer's expedition and the pinpointing of the location of the vents earlier this month follows nearly a decade of research. Finding the actual field involved extensive mapping. It also meant sampling to detect warm water and using optical sensors lowered in the ocean to determine the chemistry, both parts that involved Lilley. He said a key sensor was one developed by Ko-ichi Nakamura of the National Institute of Advanced Science and Technology, Japan, that detects reduced chemicals that are in the water as a result of having been processed through a hydrothermal vent.

A remotely operated vehicle was used to finally find the vents. The difficulties of the task are described in an expedition Web diary, see "Day 17: And then there were vents" at http://www.geobio.uib.no/View.aspx?mid=1062&itemid=90&pageid=1093&moduledefid=71.

The area around the vents was alive with microorganisms and animals. Preliminary observations suggest that the ecosystem around these Arctic vents is diverse and appears to be unique, unlike the vent communities observed elsewhere, the University of Bergen press release said. The expedition included 25 participants from five countries.

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For more information (note both contacts are at sea until July 27)

Lilley, lilley@u.washington.edu, arrives back in Seattle July 30
Pedersen, rolf.pedersen@geo.uib.no

United Nations University : Rising energy, food prices major threats to wetlands as farmers eye new areas for crops

700 leading experts meeting in Brazil urge policy makers to resist pressure to convert wetlands

Critical food shortages and growing demand for bio-fuels and hydro-electricity due to high fossil fuel prices rank among the greatest threats today to the preservation of precious wetlands worldwide as farmers and developers look for new areas for agriculture, energy crop plantations and hydro dams.

However, resisting pressures to convert wetlands is vital to avoid destroying ecosystems that provide a suite of services essential to humanity, including safe, steady local water supplies, preserving biodiversity and the large-scale capture and storage of climate warming greenhouse gases, according 700 leading world experts concluding a week-long meeting in Cuiaba, Brazil.

The experts issued the Cuiaba Declaration (appended) July 25, the final day of the 8th INTECOL International Wetlands Conference, convened on the northern edge of the world's largest tropical wetland, the Pantanal.

Wetlands include marshes, tidal marshes, peat bogs, swamps, river deltas, mangroves, tundra, lagoons and river floodplains. Among other services, they trap and store carbon in submerged organic matter, sustain biodiversity, and produce renewable natural resources, such as fish, natural pasture, timber, and wildlife. The statement stresses the rising value of wetlands in an increasingly urbanized world, especially such services as water storage and purification, and recreation.

Wetlands are under assault, however, due to agriculture, grazing, aquaculture, dams, waste disposal, invasive species and other problems caused by human activity.

"It is time to recognize the incalculable value of wetlands to all species – ours included," says conference co-chair Paulo Teixeira, Co-ordinator of the Cuiaba-based Pantanal Regional Environmental Programme, a joint effort of the United Nations University and Brazil's Federal University of Mato Grasso (UFMT), which hosted the event.

"If we don't plan and invest properly now, the cost to recreate artificially the services wetlands provide will dwarf the cost of preserving and protecting them in the first place."

In their statement, conference delegates from 28 nations lament "inadequate national development policies, lack of implementation of existing laws, and the lack of long-term land use planning that negatively affect wetlands on public and private property."

They also call for help establishing such basic information tools as a mapped inventory of wetlands based on universally-accepted definitions, which as yet do not exist. They call on the 158 nations that are party to the Ramsar Convention to help remedy these and other yawning information gaps.

They warn against creating energy and food croplands at the expense of natural vegetation and of carelessly allowing agriculture to encroach on wetlands, which causes damage through sediment, fertilizer and pesticide pollution.

Development in and around wetlands must be preceded by "sound cost-benefit analyses, including environmental and social parameters," the statement says, adding that "mitigation of many negative side-effects is not possible" once the damage is done.

A recent study shows a large wetland in arid northern Nigeria yielded an economic benefit in fish, firewood, cattle grazing lands and natural crop irrigation 30 times greater than the yield of water being diverted from the wetland into a costly irrigation project.

And, at US$15 000 per hectare per year, the economic value of flood mitigation and other services provided by wetlands is greater than any other ecosystem – seven times that of the next most valuable, tropical rainforests.

The statement notes accelerating rates of biodiversity loss, saying "freshwater biodiversity is declining faster than terrestrial or marine biodiversity, and wetland species are especially prone to decline and extinction."

The rich biodiversity of wetlands mitigates the spread of disease from animal to human. The statement says that with warmer world temperatures water-borne diseases will expand into new areas.

Of particular concern as well: the expected damage to wetlands due to climate change – and the exacerbation of climate change if wetlands continue to deteriorate and release potentially massive stores of greenhouse gases, both carbon and more potent methane.

In some parts of the world, the loss of wetlands could also displace huge populations that rely on wetlands for subsistence. According to South African research, an estimated 1 to 2 million rural poor in that country alone could be displaced as wetlands dry up, placing further strain on urban centres to create accommodation and employment.

"A modern wetland policy based on sound scientific knowledge and able to reconcile economic development with environmental protection and social welfare is required in all countries," the statement says.

"Some countries have high standards for wetland management, restoration, and protection; however, many others are far behind. Joint efforts across political boundaries are needed to combine all our efforts to stop and reverse the loss and degradation of wetlands. Sound policies and activities are needed now."

The Ramsar Convention, which regulates global wetland management and protection, requires nation signatories to establish and implement a specific wetland policy, to prepare a wetland inventory, and to maintain the ecological character of all wetlands.

"We call attention to the fact that many signatories have not yet fulfilled theses requirement and ask for immediate action from the respective governments," the statement says. "We encourage non-member states to join the convention and strengthen the global effort needed to sustainably manage wetlands."

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For additional conference information: www.cppantanal.org.br/intecol/eng/index.php

United Nations University

"Sustainable solutions for global problems of today and tomorrow."

Established by the U.N. General Assembly, UNU is an international community of scholars engaged in research, advanced training and the dissemination of knowledge related to pressing global problems. Activities focus mainly on peace and conflict resolution, sustainable development and the use of science and technology to advance human welfare. The University operates a worldwide network of research and post-graduate training centres, with headquarters in Tokyo.

Universidade Federal de Mato Grosso (UFMT)

Established in 1970, the UFMT is a public university, financed by the federal government of Brazil. Located initially in Cuiabá, the capital of Mato Grosso state, UFMT has now three more campuses, in Rondonópolis, Médio Araguaia and SINOP. The only federal university in Mato Grosso, UFMT offers courses in all fields of knowledge to more than 18,000 undergraduate and graduate students.

Cuiabá Declaration on Wetlands (draft for adoption by the final Plenary Session, 3 p.m. EDT, July 25)

The State of Wetlands and their Role in a World of Global Climate Change

This Declaration is directed to governments, international and national organizations, and decision makers, and calls attention to the ecological and legal state of wetlands and their importance for humans and biodiversity worldwide under the special consideration of global climate change scenarios.

Whereas:

1. Wetlands are situated at the interface between land on the one side and marine or fresh water ecosystems on the other. They cover a considerable part of the globe's surface and comprise different ecosystems that are permanently or periodically wet, such as mangroves, tidal marshes, peat bogs, swamps, river floodplains, riparian zones, salt lakes, and others. Some of them are highly productive systems that are widely used by humans. Wetlands support people and biodiversity and they are part of our common future under global climate change.

2. The current lack of basic knowledge regarding the global extent of wetlands is unacceptable. Effective techniques for achieving a global wetlands inventory have been demonstrated. Systematically acquired spaceborne optical and microwave remote sensing data sets are essential to identify and characterize wetlands within the framework of the Ramsar Convention and for various other purposes.

3. Wetlands suffer a number of impacts from human activities, mainly from agriculture, including grazing, aquaculture, water regulation and infrastructure, waste disposal and invasive species. Peat bogs suffer from large scale peat extraction, river floodplains are affected by the construction of dams for hydropower generation and by lateral dikes that modify the water regime and the flux of dissolved and solid materials, and also disrupt the linkages along rivers and between rivers and their floodplains.

4. Freshwater biodiversity is declining faster than terrestrial or marine biodiversity, and wetland species are especially prone to decline and extinction.

5. Rising energy prices are leading to the large-scale cultivation of plants for bio-fuels. In addition to the problems of rising food prices, the increasing demand for bio-fuels will stimulate an expansion of energy-crop plantations at the cost of areas covered by natural vegetation. We call attention to the danger of direct negative impacts on wetlands by land reclamation and drainage, and to the indirect impacts caused increased inputs of sediments, fertilizers, and pesticides from surrounding croplands. Rising energy prices also stimulate the use of hydroelectric power. We call attention to the heavy impact of large and small hydroelectric power plants on riverine wetlands and the loss of benefits for the local population. Wise social policy decisions require sound cost-benefit analyses that include environmental and social parameters in order to adapt these mega-projects to economically, ecologically and socially acceptable standards before construction is started, because mitigation of many negative side-effects is not possible.

6. Many wetlands also provide habitation and sustenance for many people. There are numerous wetland stressors that seriously affect the many important ecosystem services provided by wetlands, such as the storage and purification of water, recharge of subterranean aquifers, buffering of water discharge, maintenance of landscape heterogeneity and biodiversity, carbon storage, and production of renewable natural resources such as fishes, natural pasture, timber, wildlife, and others.

7. Global climate change scenarios for the next century project a global temperature increase of 2-6o C, a rise in sea level of 20-40 cm, and considerable changes in the total amount and/or seasonal distribution of rainfall. The change from snow fall to rain fall and accelerated melting of glaciers in parts of some continents will reduce the water retention capacity in winter and modify the discharge patterns of streams and rivers. There will be an increase of extreme climate events, such as large storms, severe droughts and floods. These changes will affect with varying strength the different eco-regions of the globe and will put at risk the important services which wetlands provide for humans and biodiversity. They also will increase the risk in some areas of spreading disease vectors affecting human health.

8. Intact wetlands can buffer the impacts of global climate change through the water cycle and maintenance of biodiversity, and reduce negative economic, social and ecological effects.

9. Wetland conservation and restoration is a necessary means to reduced greenhouse gas emission. The importance of wetlands in the global carbon cycle needs to be better assessed and integrated into global climate models and political efforts to negotiate carbon trading.

10. Large-scale wetland destruction is continuing as a consequence of inadequate national development policies, lack of implementation of existing laws, and the lack of long-term land use planning that negatively affect wetlands on public and private property. Future changes in global climate will seriously exacerbate the current situation.

11. Worldwide, human population is increasingly concentrated in urban areas. Local and regional wetlands have an exceptionally high value for water storage, water purification and recreation, but they are also under increased threat by land reclamation and pollution.

12. A modern wetland policy based on sound scientific knowledge and able to reconcile economic development with environmental protection and social welfare is required in all countries. This policy should acknowledge the value of wetlands and their ecosystem services, as well as their importance for global biodiversity. Some countries have high standards for wetland management, restoration, and protection; however, many others are far behind.

13. There are 158 countries that are signatories to the Ramsar Convention that regulates the worldwide management and protection of wetlands. The convention requires that the signatories establish and implement a specific wetland policy, to prepare a national wetland inventory, and to maintain the ecological character of all wetlands through wise use.