Neurobiologist Marie T. Filbin, a Distinguished Professor in the Department of Biological Sciences of Hunter College of the City University of New York (CUNY), has made a research breakthrough that has important long-term therapeutic potential for victims of spinal cord injuries.
Filbin has found a way to block the inhibiting function of the molecule MAG (myelin-associated glycoprotein) and all other inhibitors present in the myelin sheath that prevent the spinal cord from regenerating after injury. Her findings are reported in the January issue of Neuron magazine, published on January 28.
Up to now, researchers have been focusing on how to block individual inhibitors that prevent axons, the long part of the nerve, to regrow after injury. Filbin's is the first known discovery of a mechanism that can generally overcome all the inhibitors in myelin at once.
"We've shown that if you prime a neuron by treating it with certain growth factors called neurotrophins before exposing the neuron to MAG or myelin, you completely reverse the inhibition of axonal regrowth," explains Filbin. "The neurotrophins are affecting a molecule inside the neuron called cyclicAMP, which causes a cascade of events that ultimately block the regrowth inhibition." However, Filbin has found that no blocking effect occurs if the neuron is exposed to neurotrophins and MAG or myelin at the same time. The neuron must be "primed" first.
Filbin co-authored the article, "Prior Exposure to Neurotrophins Blocks Inhibition of Axonal Regeneration by MAG and Myelin Via a cAMP-Dependent Mechanism," with four Ph.D. students in Biology: Dongming Cai, Yingjing Shen, MariaElena DeBellard and Song Tang. Although the doctorate is granted by the CUNY Graduate Center, the Biology program is based at Hunter College. "These students worked with me night and day," says Filbin with pride.
Now that Filbin has the molecular in vitro mechanism to regenerate regrowth, her next step, she says, is to test it in vivo after spinal cord injury. This is not Filbin's first appearance in Neuron. In September 1994, she co-authored an article in this prestigious monthly on another startling discovery: MAG's ability to inhibit the regeneration of nerve cells. She also found that applying MAG antibodies to the affected cells had the reverse effect and actually fostered nerve regeneration.
Marie T. Filbin, a resident of Manhattan's Upper West Side, has been on the faculty of Hunter College's Department of Biological Sciences since 1990. Named a CUNY Distinguished Professor last year, she is also a faculty member of CUNY's Institute for Biomolecular Structure and Function, a national center for gene research based at Hunter.
Filbin, who teaches both graduate and undergraduate courses, received more than $670,000 in research grants in the past fiscal year. Her primary funders were the National Institutes for Health/National Institute of Neurological Disorders and Stroke, The National Multiple Sclerosis Society and The American Heart Association, which awarded the grant through its "Established Scientist Award." Born in the town of Lurgan just outside Belfast in Northern Ireland, she received her B.S. in biochemistry in 1978 and her Ph.D. just four years later, both from the University of Bath. Before settling in New York, she conducted postdoctoral research at Johns Hopkins University.
Hunter College, the largest college in the City University of New York, has a national reputation for its strong liberal arts and sciences curriculum. The Hunter College Center for Study of Gene Structure and Function, established in 1985 with a grant from the National Institutes of Health (NIH), provides the advanced laboratories needed by Filbin and other faculty members for their cutting-edge research. The Center is one of a small number of "Research in Minority Institutions" in the U.S. designated by the NIH. Hunter is the only college in the nation with two female Nobel laureates in medicine: Rosalyn Yalow and Gertrude Elion.
Journal
Neuron