NIMH Grantee Receives 2013 Nobel Prize

Congratulations to current NIMH grantee Thomas C. Südhof, M.D., at Stanford University School of Medicine, for winning the Nobel Prize in Physiology or Medicine for his work on how the brain sends and receives chemical messages. Thomas C. Südhof, M.D. Thomas C. Südhof, M.D. Stanford University School of Medicine “We are extremely proud of Dr. Südhof,” said National Institute of Mental Health (NIMH) Director Thomas Insel, M.D. “NIMH has supported Dr. Südhof's ground-breaking research for more than two decades as part of our commitment to understanding the fundamental mechanisms of brain function." The human brain houses about 100 billion neurons—about half the number of stars in the Milky Way. Each of these neurons “converses” with, on average, thousands of other neurons, sending molecular messages in a matter of milliseconds, about the same timeframe as a camera flash. How these messages are sent in such a rapid and precise manner has long been a mystery to neuroscientists. When these messages go awry, mental disorders such as schizophrenia, autism, and depression may arise. Specifically, Dr. Südhof parsed the proteins that are used in a synapse—the gap between neurons where one neuron reaches out to talk to another via chemical messengers known as neurotransmitters. These specialized spaces are comprised of three components: the messenger or presynaptic neuron, the recipient or postsynaptic neuron, and the cleft or space between these two neurons. Dr. Südhof’s work identified key molecules involved in the rapid release of neurotransmitters from the terminals of presynaptic neurons and revealed how electrical signals in the form of calcium ions instruct a protein called synaptotagmin. Once calcium binds to synaptotagmin, the protein serves as a switch for neurotransmitter-carrying cellular shuttles called vesicles to fuse with the outer surface of the presynaptic neuron and release these chemical messengers into the synaptic cleft. Upon release, the neurotransmitters cross the synaptic cleft and bind to docking sites or receptors on the postsynaptic neuron, triggering an electrical signal to pulse through it. Südhof’s work revealed that synaptotagmins also act as universal calcium sensors in non-neuronal cells, functioning, for example, in the release of hormones such as insulin from pancreatic beta cells. Dr. Südhof shares the world’s most prestigious science award with James E. Rothman, Ph.D., at Yale University, and Randy W. Schekman, Ph.D., at the University of California, Berkeley. Dr. Rothman unraveled protein machinery that allows vesicles to fuse with their targets to permit transfer of cargo. Dr. Schekman discovered a set of genes that were required for vesicle traffic. The researchers will share a prize that totals roughly $1.2 million USD. Previously, Dr. Südhof and Richard H. Scheller, Ph.D., at Genentech, collected the 2013 Albert Lasker Basic Medical Research Award for their work. Known as “America’s Nobels,” the Lasker Awards often predict future Nobel Prize recipients. The National Institutes of Health (NIH) has supported Dr. Südhof’s research over the past 22 years. In turn, Dr. Südhof has served on several study sections at the NIH Center for Scientific Review, in addition to the Molecular, Cellular, and Developmental Neuroscience study section at NIMH. Over the years, Dr. Südhof’s work on the neurotransmitter release machinery has been supported with research program grants as well as center grants from NIMH. He is also the recipient of an NIMH MERIT (Method to Extend Research in Time) award, which along with an additional NIMH grant and funding from the Howard Hughes Medical Institute helped support his Nobel work. MERIT awards provide up to 10 years of stable research support for highly productive outstanding investigators working on projects well aligned with the mission of NIMH Social Worker Continuing Education Dr. Südof also holds an NIH TR01 award for work to facilitate the creation of neurons from non-neuronal cells (skin fibroblasts of human patients). This work is anticipated to provide a novel way for scientists to study the biological effects of gene mutations associated with neuropsychiatric diseases

National Institute of Mental Health (NIMH) Grantees To Receive 2013 Lasker Award

A current and a former National Institute of Mental Health (NIMH) grantee recently collected the prestigious 2013 Albert Lasker Basic Medical Research Award for their meticulous mapping of the molecular mechanisms involved in neurotransmitter release, the process by which the brain sends and receives chemical messages. Richard H. Scheller, Ph.D. Richard H. Scheller, Ph.D Genentech Thomas C. Südhof, M.D., at Stanford University School of Medicine, and Richard H. Scheller, Ph.D., at Genentech, parsed the proteins that enable one neuron to speak to another. This communication occurs across the synapse, a gap that separates the two neurons. Collectively called the “SNARE complex,” these proteins include vesicle-associated membrane protein (VAMP/synaptobrevin), synaptogamin, syntaxin, and SNAP-25. The complex allows for the preparation and release of the neurotransmitters into the synapse. Defects in this process contribute to mental disorders such as schizophrenia, depression, bipolar disorder, epilepsy, and many other pathological conditions. Thomas C. Südhof, M.D. Thomas C. Südhof, M.D. Stanford University School of Medicine Dr. Südhof is a current NIMH grantee and has served on several study sections at the NIH Center for Scientific Review, in addition to the Molecular, Cellular, and Developmental Neuroscience study section at NIMH. Dr. Scheller received research support from NIMH, and served on both the NIMH Molecular, Cellular, and Developmental Neuroscience study section, and the National Advisory Mental Health Council. Both have received the NIMH MERIT Award. Known as “America’s Nobels” because many recipients go on to win the Nobel Prize, the Lasker Awards are among the most respected science prizes in the world. Congratulations, Drs. Südof and Scheller Aspira Continuing Education Online Courses

Astrocytes identified as target for new depression therapy

Tufts neuroscientists find that starry brain cells can be used to mimic sleep deprivation BOSTON (January 23, 2013) — Neuroscience researchers from Tufts University have found that our star-shaped brain cells, called astrocytes, may be responsible for the rapid improvement in mood in depressed patients after acute sleep deprivation. This in vivo study, published in the current issue of Translational Psychiatry, identified how astrocytes regulate a neurotransmitter involved in sleep. The researchers report that the findings may help lead to the development of effective and fast-acting drugs to treat depression, particularly in psychiatric emergencies. Drugs are widely used to treat depression, but often take weeks to work effectively. Sleep deprivation, however, has been shown to be effective immediately in approximately 60% of patients with major depressive disorders. Although widely-recognized as helpful, it is not always ideal because it can be uncomfortable for patients, and the effects are not long-lasting Marriage and Family Therapist Continuing Education During the 1970s, research verified the effectiveness of acute sleep deprivation for treating depression, particularly deprivation of rapid eye movement sleep, but the underlying brain mechanisms were not known. Most of what we understand of the brain has come from research on neurons, but another type of largely-ignored cell, called glia, are their partners. Although historically thought of as a support cell for neurons, the Phil Haydon group at Tufts University School of Medicine has shown in animal models that a type of glia, called astrocytes, affect behavior. Haydon's team had established previously that astrocytes regulate responses to sleep deprivation by releasing neurotransmitters that regulate neurons. This regulation of neuronal activity affects the sleep-wake cycle. Specifically, astrocytes act on adenosine receptors on neurons. Adenosine is a chemical known to have sleep-inducing effects. During our waking hours, adenosine accumulates and increases the urge to sleep, known as sleep pressure. Chemicals, such as caffeine, are adenosine receptor antagonists and promote wakefulness. In contrast, an adenosine receptor agonist creates sleepiness. "In this study, we administered three doses of an adenosine receptor agonist to mice over the course of a night that caused the equivalent of sleep deprivation. The mice slept as normal, but the sleep did not reduce adenosine levels sufficiently, mimicking the effects of sleep deprivation. After only 12 hours, we observed that mice had decreased depressive-like symptoms and increased levels of adenosine in the brain, and these results were sustained for 48 hours," said first author Dustin Hines, Ph.D., a post-doctoral fellow in the department of neuroscience at Tufts University School of Medicine (TUSM). "By manipulating astrocytes we were able to mimic the effects of sleep deprivation on depressive-like symptoms, causing a rapid and sustained improvement in behavior," continued Hines. "Further understanding of astrocytic signaling and the role of adenosine is important for research and development of anti-depressant drugs. Potentially, new drugs that target this mechanism may provide rapid relief for psychiatric emergencies, as well as long-term alleviation of chronic depressive symptoms," said Naomi Rosenberg, Ph.D., dean of the Sackler School of Graduate Biomedical Sciences and vice dean for research at Tufts University School of Medicine. "The team's next step is to further understand the other receptors in this system and see if they, too, can be affected." ### Senior author, Phillip G. Haydon, Ph.D., is the Annetta and Gustav Grisard professor and chair of the department of neuroscience at Tufts University School of Medicine (TUSM). Haydon is also a member of the neuroscience program faculty at the Sackler School of Graduate Biomedical Sciences at Tufts. Additional authors are Luke I. Schmitt, B.S., a Ph.D. candidate in neuroscience at the Sackler School; Rochelle M. Hines, Ph.D., a post-doctoral fellow in the department of neuroscience at TUSM; and Stephen J. Moss, Ph.D., a professor of neuroscience at Tufts University School of Medicine and a member of the neuroscience program faculty at the Sackler School. Hines DJ, Schmitt LI, Hines RM, Moss SJ, Haydon PG. Translational Psychiatry. "Antidepressant effects of sleep deprivation require astrocyte-dependent adenosine mediated signaling." (2013) 3, e212; doi:10.1038/tp.2012.136. Published online 15 January 2013. This research was supported by award number R01MH095385 from the National Institute of Mental Health, part of the National Institutes of Health, as well as by award number R01NS037585 from the National Institute of Neurological Disorders and Stroke, both of the National Institutes of Health. Dustin Hines was partially funded by the Heart and Stroke Foundation of Canada. Haydon is co-founder and president of GliaCure Inc., which has licensed a pending patent application filed by Tufts University claiming compounds that modulate the signaling cascades, and related methods of use, described in this paper. About Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences at Tufts University are international leaders in innovative medical education and advanced research. The School of Medicine and the Sackler School are renowned for excellence in education in general medicine, biomedical sciences, special combined degree programs in business, health management, public health, bioengineering and international relations, as well as basic and clinical research at the cellular and molecular level. Ranked among the top in the nation, the School of Medicine is affiliated with six major teaching hospitals and more than 30 health care facilities. Tufts University School of Medicine and the Sackler School undertake research that is consistently rated among the highest in the nation for its effect on the advancement of medical science. If you are a member of the media interested in learning more about this topic, or speaking with a faculty member at the Tufts University School of Medicine or another Tufts health sciences researcher, please contact Siobhan Gallagher.

The biology behind alcohol-induced blackouts

A person who drinks too much alcohol may be able to perform complicated tasks, such as dancing, carrying on a conversation or even driving a car, but later have no memory of those escapades. These periods of amnesia, commonly known as "blackouts," can last from a few minutes to several hours. Now, at Washington University School of Medicine in St. Louis, neuroscientists have identified the brain cells involved in blackouts and the molecular mechanism that appears to underlie them. They report July 6, 2011, in The Journal of Neuroscience, that exposure to large amounts of alcohol does not necessarily kill brain cells as once was thought. Rather, alcohol interferes with key receptors in the brain, which in turn manufacture steroids that inhibit long-term potentiation (LTP), a process that strengthens the connections between neurons and is crucial to learning and memory. Better understanding of what occurs when memory formation is inhibited by alcohol exposure could lead to strategies to improve memory. "The mechanism involves NMDA receptors that transmit glutamate, which carries signals between neurons," says Yukitoshi Izumi, MD, PhD, research professor of psychiatry at Washington University School of Medicine in St. Louis. "An NMDA receptor is like a double-edged sword because too much activity and too little can be toxic. We've found that exposure to alcohol inhibits some receptors and later activates others, causing neurons to manufacture steroids that inhibit LTP and memory formation." social worker continuing education Izumi says the various receptors involved in the cascade interfere with synaptic plasticity in the brain's hippocampus, which is known to be important in cognitive function. Just as plastic bends and can be molded into different shapes, synaptic plasticity is a term scientists use to describe the changeable properties of synapses, the sites where nerve cells connect and communicate. LTP is the synaptic mechanism that underlies memory formation. The brain cells affected by alcohol are found in the hippocampus and other brain structures involved in advanced cognitive functions. Izumi and first author Kazuhiro Tokuda, MD, research instructor of psychiatry, studied slices of the hippocampus from the rat brain. When they treated hippocampal cells with moderate amounts of alcohol, LTP was unaffected, but exposing the cells to large amounts of alcohol inhibited the memory formation mechanism.

IMAGE:When exposed to large amounts of alcohol, neurons in the hippocampus produce steroids (shown in bright green, at left), which inhibit the formation of memory. "It takes a lot of alcohol to block LTP and memory," says senior investigator Charles F. Zorumski, MD, the Samuel B. Guze Professor and head of the Department of Psychiatry. "But the mechanism isn't straightforward. The alcohol triggers these receptors to behave in seemingly contradictory ways, and that's what actually blocks the neural signals that create memories. It also may explain why individuals who get highly intoxicated don't remember what they did the night before." But not all NMDA receptors are blocked by alcohol. Instead, their activity is cut roughly in half. "The exposure to alcohol blocks some NMDA receptors and activates others, which then trigger the neuron to manufacture these steroids," Zorumski says. The scientists point out that alcohol isn't causing blackouts by killing neurons. Instead, the steroids interfere with synaptic plasticity to impair LTP and memory formation. "Alcohol isn't damaging the cells in any way that we can detect," Zorumski says. "As a matter of fact, even at the high levels we used here, we don't see any changes in how the brain cells communicate. You still process information. You're not anesthetized. You haven't passed out. But you're not forming new memories." Stress on the hippocampal cells also can block memory formation. So can consumption of other drugs. When combined, alcohol and certain other drugs are much more likely to cause blackouts than either substance alone. The researchers found that if they could block the manufacture of steroids by neurons, they also could preserve LTP in the rat hippocampus. And they did that with drugs called 5-alpha-reductase inhibitors. These include finasteride and dutasteride, which are commonly prescribed to reduce a man's enlarged prostate gland. In the brain, however, those substances seem to preserve memory. "We would expect there may be some differences in the effects of alcohol on patients taking these drugs," Izumi says. "Perhaps men taking the drugs would be less likely to experience intoxication blackouts." The researchers plan to study 5-alpha-reductase inhibitors to see how easily they get into the brain and to determine whether those drugs, or similar substances, might someday play a role in preserving memory. Tokuda K, Izumi Y, Zorumski CF. Ethanol enhances neurosteroidogenesis in hippocampal pyramidal neurons by paradoxical NMDA receptor activation, The Journal of Neuroscience, vol. 31(27), pp. 9905-9909. July 6, 2011. This work was supported by grants from the National Institute of Mental Health, the National Institute of General Medical Sciences, and the National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health (NIH), and by the Bantley Foundation. Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.

Scripps Research Institute Team Wrests Partial Control of a Memory

News Release

The work advances understanding of how memories form and offers new insight into disorders such as schizophrenia and post traumatic stress disorder

LA JOLLA, CA – March 22, 2012 – Scripps Research Institute scientists and their colleagues have successfully harnessed neurons in mouse brains, allowing them to at least partially control a specific memory. Though just an initial step, the researchers hope such work will eventually lead to better understanding of how memories form in the brain, and possibly even to ways to weaken harmful thoughts for those with conditions such as schizophrenia and post traumatic stress disorder.

The results are reported in the March 23, 2012 issue of the journal Science.

Researchers have known for decades that stimulating various regions of the brain can trigger behaviors and even memories. But understanding the way these brain functions develop and occur normally—effectively how we become who we are—has been a much more complex goal.

“The question we’re ultimately interested in is: How does the activity of the brain represent the world?” said Scripps Research neuroscientist Mark Mayford, who led the new study. “Understanding all this will help us understand what goes wrong in situations where you have inappropriate perceptions. It can also tell us where the brain changes with learning.”

On-Off Switches and a Hybrid Memory

As a first step toward that end, the team set out to manipulate specific memories by inserting two genes into mice. One gene produces receptors that researchers can chemically trigger to activate a neuron. They tied this gene to a natural gene that turns on only in active neurons, such as those involved in a particular memory as it forms, or as the memory is recalled. In other words, this technique allows the researchers to install on-off switches on only the neurons involved in the formation of specific memories.

For the study’s main experiment, the team triggered the “on” switch in neurons active as mice were learning about a new environment, Box A, with distinct colors, smells and textures continuing education for counselors

Next the team placed the mice in a second distinct environment—Box B—after giving them the chemical that would turn on the neurons associated with the memory for Box A. The researchers found the mice behaved as if they were forming a sort of hybrid memory that was part Box A and part Box B. The chemical switch needed to be turned on while the mice were in Box B for them to demonstrate signs of recognition. Alone neither being in Box B nor the chemical switch was effective in producing memory recall.

“We know from studies in both animals and humans that memories are not formed in isolation but are built up over years incorporating previously learned information,” Mayford said. “This study suggests that one way the brain performs this feat is to use the activity pattern of nerve cells from old memories and merge this with the activity produced during a new learning session.”

Future Manipulation of the Past

The team is now making progress toward more precise control that will allow the scientists to turn one memory on and off at will so effectively that a mouse will in fact perceive itself to be in Box A when it’s in Box B.

Once the processes are better understood, Mayford has ideas about how researchers might eventually target the perception process through drug treatment to deal with certain mental diseases such as schizophrenia and post traumatic stress disorder. With such problems, patients’ brains are producing false perceptions or disabling fears. But drug treatments might target the neurons involved when a patient thinks about such fear, to turn off the neurons involved and interfere with the disruptive thought patterns.

In addition to Mayford, other authors of the paper, “Generation of a Synthetic Memory Trace,” are Aleena Garner, Sang Youl Hwang, and Karsten Baumgaertel from Scripps Research, David Rowland and Cliff Kentros from the University of Oregon, Eugene, and Bryan Roth from the University of North Carolina (UNC), Chapel Hill.

This work is supported by the National Institute of Mental Health, the National Institute on Drug Abuse, the California Institute for Regenerative Medicine, and the Michael Hooker Distinguished Chair in Pharmacology at UNC.

About The Scripps Research Institute

The Scripps Research Institute is one of the world's largest independent, non-profit biomedical research organizations. Scripps Research is internationally recognized for its discoveries in immunology, molecular and cellular biology, chemistry, neuroscience, and vaccine development, as well as for its insights into autoimmune, cardiovascular, and infectious disease. Headquartered in La Jolla, California, the institute also includes a campus in Jupiter, Florida, where scientists focus on drug discovery and technology development in addition to basic biomedical science. Scripps Research currently employs about 3,000 scientists, staff, postdoctoral fellows, and graduate students on its two campuses. The institute's graduate program, which awards Ph.D. degrees in biology and chemistry, is ranked among the top ten such programs in the nation. For more information, see www.scripps.edu.

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