2003 First Cycle Research Grant Recipients
$1,975,950.10

William A. Barton, Ph.D., Sloan Kettering Institute, New York, New York
$74,250.00, 1-year Grant
Sturctural study of Nogo, NogoR, and p75NTR
Research category: Growth inhibition

Nogo is a powerful growth-inhibiting protein that occurs naturally in myelin, the insulating sheath that normally surrounds axons. Dr. Barton will use the sophisticated tools of x-ray crystallography, biochemistry, biophysics, and molecular biology, he plans to characterize the structure of the Nogo molecule. He also will study its receptors, the molecular partners on the cell membrane that enable Nogo to influence the behavior of a neuron. Dr. Barton also will try to pinpoint how Nogo interacts with those receptors to produce the signals that stop regenerating axons in their tracks. His long-term goal is to use what he learns about Nogo and its receptors to find molecules that could block the action of Nogo and permit injured nerve cells to regenerate.

Gerarld R. Crabtree, M.D., Stanford University School of Medicine, Stanford, California
$149,964.00, 2-year Grant
Understanding and recapturing patterns of embryonic neurite outgrowth
Research category: Growth inhibition

During embryonic development, more than 100 billion cells systematically fall into place, hook up with just the right target cells, and create the brain and spinal cord. Neurons in mature organisms seem unable to reprise this dramatic performance after disease, stroke, or injury destroys nerve pathways. Dr. Crabtree and his colleagues are trying to understand differences between the developing and mature nervous system. In the developing nervous system, they have found that a protein known as NFAT is plentiful in a critical communication pathway but NFAT virtually disappears in mature nerve cells. This signaling pathway relays crucial messages between the growing axons of new nerve cells and their nucleus and helps those axons to find their way to the correct destination. In this project, researchers will try to identify the mechanisms that cause NFAT to vanish and will use specially bred mice to test whether the reintroduction of NFAT promotes axon regeneration following spinal cord injury. These experiments could further the understanding of why the adult brain and spinal cord cannot repair themselves.

David D. Fuller, Ph.D., University of Wisconsin, Madison, Wisconsin
$150,000, 2-year Grant
Plasticity in spinal respiratory pathways following treadmill exercise
Research category: Concomitant function

For people whose spinal cord injuries severely impair their breathing, respiratory complications are the leading cause of illness and death. Exercise therapy, like locomotor training, appears not only to restore some walking and standing ability but also to stimulate the spinal nerves that activate the muscles that enable someone to inhale and exhale. In this study, Dr. Fuller will be the first researcher actually to test whether locomotor training reshapes circuits in the spinal cord and whether these changes improve the performance of surviving respiratory neurons following an incomplete spinal cord injury. Using rat models, Dr. Fuller and his team also hope to learn precisely how these improvements occur. They suspect that months of frequent exercise sessions enhance the activity of serotonin and glutamate, two important neurotransmitters that facilitate cell-to-cell communication and seem to aid breathing. Dr. Fuller will run experiments to see if the receptors for serotonin and glutamate need to be activated for breathing to improve. His results could help doctors ease breathing problems in people with high level spinal cord injuries.

Francis John Golder, DVM, Ph.D., DACVA, University of Wisconsin, Madison, Wisconsin
$149,600.00, 2-year Grant
Respiratory functional recovery after cervical spinal cord injury: strengthening existing synaptic pathways
Research category: Concomitant function

Breathing difficulty poses the greatest risk to patients with spinal cord injuries of the neck. Dr. Golder is trying to develop therapies that exploit the body's own reflexes and repair mechanisms to help people with these grave injuries to breathe better. He has been testing ways to increase the activity of the phrenic nerve, which controls the diaphragm, the main muscle used to breathe. Increased phrenic nerve activity leads to increased breath volume. The phrenic nerve naturally becomes more active if the supply of oxygen in the bloodstream falls, a condition called hypoxia. When the hypoxia ends, the phrenic nerves gradually return to normal. Dr. Golder has found that he can extend the period of heightened phrenic nerve activity by using intermittent hypoxia. This approach involves three cycles of breathing low concentrations of oxygen for five minutes, followed by a five-minute rest. He has observed that after the last cycle, the activity of the phrenic nerves gradually increases during the next hour and remains elevated, a conditioning effect called long-term facilitation. Hypoxia causes this effect by releasing the neurotransmitter serotonin into the spinal cord and ultimately increasing the amount of air delivered by each inhalation.  In this project, Dr. Golder first will use intermittent hypoxia to release serotonin, stimulate activity of the phrenic nerves, and improve breathing in animal models. In the second part of this study, he will consider how spinal serotonin decreases immediately after a spinal cord injury and then returns to normal concentrations. He hopes to learn how much time must elapse until serotonin levels are high enough for the hypoxia treatment to work. His results could help doctors to develop a fairly simple, cost-effective way to train spinal cord patients to breathe better.

Barbara Grimpe, Ph.D., Case Western Reserve University, Cleveland, Ohio
$133,684.10, 2-year Grant
Down-regulation of the xylosyltransferase 1, the GAG-chain initiating enzyme, and the use of bridge-building Schwann cells to stimulate regeneration in the spinal cord
Research category: Promotion of axon growth and remyelination

Chondroitin sulfate proteoglycans are protein molecules with many side chains of carbohydrates. These hefty molecules normally comprise part of the extracellur matrix that surrounds and supports every cell. But after a spinal cord injury, their concentration increases around the lesion, and they become a major component of the scar that forms, making the area inhospitable to regenerating axons. Researchers have tested an enzyme called Chondroitinase ABC that breaks up these molecules, increasing the likelihood that regenerating axons could bypass the lesion and restore partial function. However, this approach leaves parts of the carbohydrate side chains undigested, and these remnants still inhibit axon outgrowth. To eliminate all traces of proteoglycans, Dr. Grimpe is testing a DNA enzyme, which can be tailored to cleave messenger RNA (mRNA) at a specific site. mRNA transmits the instructions for protein production from DNA in a cell's nucleus to the cytoplasm, where proteins are made. Dr. Grimpe has designed a DNA enzyme that blocks the synthesis of the carbohydrate side chains attached to proteoglycans, alleviating the need to dice them up later. When she combined this treatment with the transplantation of sensory neurons, which readily regenerate their axons after an injury, axons from the transplants easily bypassed a spinal cord lesion. In subsequent in vitro studies, she cultured combinations of astrocytes, which support and nourish neurons; and Schwann cells, which produce myelin insulation for axons in the peripheral nervous system. Naturally occurring polyglycans usually keep these two cell types apart. But after Dr. Grimpe added the new DNA enzyme to the cell cultures, the Schwann cells developed the unusual ability to invade astrocyte territory. In this study, Dr. Grimpe will continue to analyze the action of the DNA enzyme. She also will test it in conjunction with transplanted Schwann cells to learn whether the enzyme will enable the Schwann cells to integrate into the host tissue and promote axon regeneration in animals with spinal cord injuries.

Bryan C Hains, Ph.D., Yale University School of Medicine, New Haven, Connecticut
$136,259.00, 2-year Grant
Sodium channels and pain after spinal cord injury
Research category: Concomitant function

Chronic pain plagues many people living with spinal cord injuries. Sensations that usually are not painful ¾ heat and cold or clothing brushing the skin ¾ may cause severe discomfort. The reasons for this difficult-to-treat problem are poorly understood and the underlying mechanisms to this hypersensitivity have received little attention. Scientists have noticed that spinal cord injuries seem to alter electrical activity in dorsal horn sensory neurons, and these changes may be responsible for the inappropriate pain messages.  Dorsal horn sensory neurons are the nerve cells that normally transmit pain signals from the periphery of the body to the brain. Using a rodent model, Dr. Hains will investigate how these important cells become over-excited following a spinal cord injury.  He suspects that changes in the way the cells process sodium causes them to misfire. Dr. Hains will use a combination of techniques, including molecular biology, electrophysiology, and behavioral assessments to pinpoint the origins of the abnormal activity of these cells and to explain why they remain permanently overactive. These insights could lead to treatments that either would prevent the pain-signaling cells from becoming hyperactive in the first place or would return them to their normal state.

Mark Henkemeyer, Ph.D., University of Texas Southwestern Medical Center, Dallas, Texas
$150,000.00, 2-year Grant
Eph-Ephrin signaling in the growth cone
Research category: Axon guidance, synapse formation and neurotransmission

New axons have a complex built-in guidance system. Their leading edge, or growth cone, is lined with receptor molecules that sniff out guidance cues, or ligands, in their environment. When a ligand and its partner receptor meet up, the receptor launches a chain of messages that order the growth cone either to continue full speed ahead, stop in its tracks, or turn and run. The Henkemeyer laboratory has focused on a key group of the turn-and-run, or repulsive, receptors known as Eph receptors and their partners, the Ephrin ligands. These pairs are active following a spinal cord injury and may prevent the regeneration of replacement axons. In earlier studies, Dr. Henkemeyer used genetically-altered mice to prove that Eph-Ephrin interactions are crucial to the original wiring of the corticospinal tract. This tract is the main bundle of nerve fibers that connect the brain with the spinal cord and control voluntary movements like walking. The Henkemeyer laboratory also developed an in vitro technique for studying how Eph and Ephrin affect axon pathfinding. In this project, Dr. Henkemeyer will continue to use both animal models and in vitro studies to develop chemical agents that can disrupt Eph-Ephrin signaling. If Eph-Ephrin interactions do interfere with axon regeneration, then these blocking agents would be valuable therapeutic tools.

Carole Ho, M.D., Stanford University School of Medicine, Stanford, California
$136,180.00, 2-year Grant
Identification and characterization of neuronal regeneration associated genes induced by cAMP and laminin by expression profiling
Research category: Promotion of axon growth and remyelination

Dr. Ho, a physician researcher, wants to learn more about the mechanisms that, under the right circumstances, enable injured neurons to regrow their axons. In this study, she will try to identify the genes that are critical to axonal growth in the injured brain and spinal cord. She will apply several techniques known to elicit axon regeneration to dorsal root ganglion neurons, the nerve cells that carry sensory information to the spinal cord.  Her experiments will involve both laboratory cultures and animal models. Then, using a sophisticated gene profiling system called microarray technology, she will analyze tissue samples from the neurons. This technology will enable her to identify which genes are active during regeneration in each experiment and single out those that are activated, or expressed, in all the scenarios. Knowing the identity of these common genes  will be an important step in restarting the growth process in the injured spinal cord.

John H. Martin, Ph.D., Research Foundation for Mental Hygiene, Inc., New York, New York
$148,616.00, 2-year Grant
Engineering spinal connections to bypass spinal injury
Research category: Promotion of axon growth and remyelination

Dr. Martin and his colleagues have devised a novel transplant technique that uses a peripheral nerve to bridge the gap created by a spinal cord injury. This approach exploits the capacity of peripheral nerves to regenerate after an injury and the ability of motor control centers in the brain to assume new roles. The technique involves disconnecting a redundant spinal nerve that exits the cord above the level of injury from its target muscle. The disconnected end then is inserted into the spinal cord below the injury. Motor axons from the repositioned nerve then grow into the cord and form synapses with the spinal neurons that activate muscles. Dr. Martin has shown that these new synapses function because muscles contract when the transplanted nerve causes is stimulated. This relatively easy transplant technique has great promise for treating both new and old injuries for several key reasons. The body does not reject the transplanted nerve, working synapses form rapidly, and the procedure can be done long after an injury. Most important, Dr. Martin expects that the brain will adapt to the newly formed circuitry and assume management of groups of nerve cells in the spinal cord, like those that control the bladder or generate the muscle contractions for walking. This new control pattern would then restore function. In this study, Dr. Martin plans to confirm that axons from the inserted nerve do conduct signals from the brain to the spinal cord below the injury that then controll  movements.. He also will investigate how best to promote the long-term survival of the regenerated axons and their synapses. If these experiments are successful, clinical trials might soon follow.

Mehdi M. Mirbagheri, Ph.D., Rehabilitation Institute of Chicago, Chicago, Illinois
$147,397.00, 2-year Grant
Restoration of neuromuscular function in spinal cord injury
Research category: Rehabilitation

Nearly everyone with a spinal cord injury suffers from some form of spasticity, including exaggerated reflexes and involuntary muscle spasms. Spasticity disrupts routine activities and exacts a physical, emotional and social toll. Yet its causes are not well understood.  An effective treatment would greatly improve the quality of life for people with spinal cord injuries and their families. Dr. Mirbagheri and his team plan to use sophisticated electromechanical techniques to evaluate whether a muscle relaxant called Tizandine and exercise therapy, either alone or in combination, can treat spasticity and improve voluntary control of the muscles involved in walking. He will test these approaches in people with incomplete spinal cord injuries, which comprise half of all spinal cord injuries. In the first part of the study, researchers will test the combination of Tizandine and robotic locomotor training, in which a mechanical device propels someone's legs to make stepping motions on a moving treadmill. Dr. Mirbagheri expects that the dual therapy will result in greater and faster improvements in spasticity and muscle control than either intervention could on its own. Next, he will assess the effects of these treatments on muscle strength and walking by measuring voluntary contractions and walking speed. In theory, Tizandine may improve speed, and locomotor training will improve both strength and speed. Dr. Mirbagheri is hopeful that the combined treatments will improve strength and gait speed better than either intervention alone. These findings may offer scientists new insights into how these therapies work and give doctors better ways to alleviate spasticity and improve walking.

Sergei N. Prokopenko, Ph.D., Emory University, Atlanta, Georgia
$75,000.00, 1-year Grant
Signaling pathways of Derailed axon guidance receptor controlling a choice of commissures in the central nervous system
Research category: Axon guidance, synapse formation and neurotransmission

For an organism to work properly, be it a fruitfly or a human, the left side of the body must know what the right side does and vice versa. To accomplish bilateral coordination between sensory, locomotor, and cognitive functions, a significant number of neurons must send axons from one side of the body to the other during development. In a fruit fly, for example, as many as ninety per cent of its axons must execute this crucial maneuver.  Researchers have already found some signaling molecules that control whether axons travel from one side of the body to the other. Yet no one knows how axons choose among the major pathways that cross the midline. A key receptor called Derailed has been discovered that enables axons to choose between two of the pathways. Derailed appears to interact with an unknown repellent signal, or ligand, which activates a do-not-enter signaling cascade inside the axon tip, causing it to change direction.
In this two-part study, Dr. Prokopenko will try to clarify precisely how Derailed operates in the fruit fly Drosophila. First, he will analyze how Derailed works inside the axon to accomplish repulsion. Using genetic engineering, he will create modified versions of Derailed and reintroduce them into fruit flies. By process of elimination, Dr. Prokopenko will identify which intracellular signaling partners are required  to control the direction the axon heads. In the second part of this study, he will use both biochemical and genetic screens to search for the partners that Derailed recruits to signal the axon to stop. The eventual goal is to develop therapeutic drugs that would control this signaling mechanism.

Barbara Ranscht, Ph.D., The Burnham Institute, La Jolla, California
$150,000.00, 2-year Grant
Cadherins in establishing connectivity in the spinal cord
Research category: Axon guidance, synapse formation and neurotransmission

Dr. Ranscht has been studying how, during development, similar groups of neurons amass, forge the right connections, and form distinct parts of the central nervous system. Her research has focused on a group of sticky proteins called cadherins, which latch on to one another. She and other researchers have proved that matching cadherins on the surface of neurons ¾ what Dr. Ranscht calls the cadherin code ¾ help neurons to sort themselves into pools that become specific parts of the brain. Dr. Ranscht will now turn her attention to the assembling of the circuits that control muscles. Using chick embryos, she will test whether cadherin codes guide the formation of nerve pathways between the brain, spinal cord, and specific muscles. She predicts that the same codes that help build these original connections need to be reactivated so that severed axons can reconnect.

Stephen I. Ryu, M.D., Stanford University School of Medicine, Stanford, California
$150,000.00, 2-year Grant
Enhancing the performance of cortically controlled prosthetic arm systems
Research category: Rehabilitation

Spinal cord injuries, as well as neurological diseases, can rob people of the ability to reach out, whether for a teacup or a child. In some of these cases, however, the brain circuitry that controls a reach remains intact, but the pathway for voluntary commands to move the arm has been damaged. In recent experiments with both humans and primates, scientists have tapped directly into the brain to enable subjects to control prosthetic reaching devices. Yet researchers have only limited knowledge of how the brain encodes commands to the limbs, and they are only beginning to develop the mathematical tools called decode algorithms that translate electrical signals from the brain into a form that can be used to activate a prosthesis. In this study, Dr. Ryu first will train monkeys to reach out to touch targets on a computer screen. He will then implant electrode arrays into the animals to record their brain signals as they perform the maneuvers. These recordings will enable him to identify electrical patterns associated with both the animals' planning and executing of discreet motions. From those patterns, he will generate new decode algorithms, including the first ones that will combine data from the pre-reach planning phase with the data from the movement phase. These algorithms will be used to move a cursor on the computer screen to reproduce the desired monkey reach in response to the actual neuronal signals from the monkeys' brains. The monkeys eventually will learn to control the cursor to perform the tasks without actually using their arms. Finally, Dr. Ryu will attempt to improve the performance of these prosthetic systems by enhancing the decode algorithms. He predicts that the best algorithms will enable monkeys to complete a virtual reach as quickly and precisely as they would an actual one. These experiments promise to improve prosthetic technology, and one day might enable researchers to restore movement to someone's paralyzed limbs, a goal once thought possible only in the realm of science fiction.

Rajeev Sivasankaran, Ph.D., Children's Hospital Boston, Boston, Massachusetts
$150,000.00, 2-year Grant
Investigating the role of protein kinase C in axon regeneration
Research category: Promotion of axon growth and remyelination

Both the myelin that ensheaths axons and the scar tissue that forms around damaged spinal tissue prevent axons from regrowing after an injury. Researchers are beginning to identify these molecules and their partners, or receptors, on the cell surface. When activated, these receptors initiate an intracellular signaling cascade that changes what the cell does. Although scientists have found two key receptors involved in this process, the cascade itself is poorly understood. Dr. Sivasankaran has helped to identify what appears to be an important signaling molecule called protein kinase C (PKC), which is activated by both myelin and scar tissue inhibitors. Because PKC has also been shown to promote axon growth, Dr. Sivasankaran hypothesizes that signals from myelin and scar tissue cause PKC to turn on novel molecules that somehow command the growing tip of the axon to stop extending. In this two-part study, Dr. Sivasankaran hopes to identify these signaling molecules, which could be ideal targets for future treatments. Next, he will test drugs on rat models that are known to inhibit PKC at the site of a spinal cord injury. He expects that the drugs will transform the area around the injury into more fertile ground for nerve cells to regrow their axons. He will assess whether these experimental treatments lead not only to axon regeneration but also to recovery of function.

Ernest F. Terwilliger, Ph.D., Beth Israel Deaconess Medical Center, Boston, Massachusetts
$75,000, 1-year Grant
Targeting therapeutic gene transfer to spinal cord motor neurons
Research category: New tools for spinal cord research

Gene therapy promises to enable doctors to limit the severity of a spinal cord injury and induce the body to replace the lost connections that result in paralysis. In gene therapy, beneficial genes are administered to patients in hopes that the genes will trigger a therapeutic change. The new genes may, for example, spur the production of neurotrophins, substances that help axons grow and survive, or block the action of naturally occurring growth inhibitors that prevent regeneration. Dr. Terwilliger wants to improve the molecular vehicles, or vectors, that might one day ferry therapeutic genes to motor neurons, the nerve cells that carry messages from the brain to the muscles via the spinal cord. Most vectors are forms of highly purified viruses that no longer can make people ill but still can readily "infect" cells. In this study, Dr. Terwilliger will try to perfect a novel vector that combines a viral vector with a fragment of Tetanus neurotoxin. This fragment is incapable of causing the paralytic disease, but should enable this gene "bus" to head straight for motorneurons, the nerve cells that Tetanus normally attacks. Dr. Terwilliger's team first will test these vectors in healthy mice to make certain that the vectors do single out and incorporate into the rodents' motor neurons. He then will try using the vectors to deliver therapeutic genes to mouse models of a human genetic neurological disorder called Spinal Muscular Atrophy (SMA) that weakens and destroys motor neurons. If successful, this project could quickly advance to clinical trials of the vector and foster new approaches to gene therapy for the treatment of the diseased or damaged spinal cord.