- Findings May Someday Inform Treatments for Spinal Cord, Other Nerve
Injuries -
PHILADELPHIA, Oct. 8 /PRNewswire-USNewswire/ -- A protein that enables
nerve cells to communicate with each other plays a key role in controlling
the developing nervous system. Research into how that protein helps precise
connections to form among nerve cells may provide a basis for eventual
treatments for patients who suffer injuries to their nervous system,
including spinal cord injury.
"This expands our basic knowledge of how the nervous system develops in
animals and humans," said study leader Robert Kalb, M.D., a neurologist at
The Children's Hospital of Philadelphia. Kalb and colleagues published two
studies in the Journal of Neuroscience.
The first study, published Oct. 1, showed that the protein GluR1, which
is a receptor for the neurotransmitter glutamate, promotes the growth of
dendrites, both in nerve cell cultures and in the nervous system of mice.
Dendrites are branching extensions of nerve cells that carry signals into
the cell. The most vigorous dendrite growth occurs shortly after birth,
when GluR1 is present on the surface of the cell. As neurons mature, GluR1
is lost from the cell surface of some neurons, and dendrites stop growing.
Kalb and colleagues showed that suppressing GluR1 activity reduced
dendrite growth, and led to poor development of connections between
neurons. As a result of these defects, mice displayed less strength and
less endurance on treadmill tests. On the other hand, using genetic
manipulation that led to cell surface expression of GluR1 protein in adult
mice led to supernormal motor performance, as shown by longer duration on
treadmills.
"Our observations could be relevant to helping patients recover motor
function after they suffer an injury to the spinal cord or other parts of
the nervous system," said Kalb. "Often neural circuits remain intact after
an injury, and are capable of reorganizing themselves, given the proper
stimulation. If we can eventually manipulate this protein's activity in
neurons, we might enhance communication among those neurons, and allow
patients to receiver greater benefit from therapeutic exercises."
The second study by Kalb and colleagues, published Oct. 8, described
the molecular pathways by which GluR1 binds with another protein, SAP97, to
control dendrite growth during the early postnatal period. "Our work
suggests that GluR1 brings the scaffolding protein SAP97 to the membrane of
nerve cells, where it can receive pro-growth signals to build dendrites."
Although both studies were performed in mice, the neurodevelopmental
process is considered to be similar for all mammals. "The first few weeks
of postnatal life are a critical period for sculpting the architecture of
the nervous system," added Kalb. "Greater understanding of how neural
architecture develops normally may give us insight into how to intervene
when things go wrong."
Both studies received grant support from the U.S. Public Health
Service, part of the National Institutes of Health. The Pennsylvania
Department of Health also provided funding. Dr. Kalb's co-authors included
collaborators from the United States (from The Children's Hospital of
Philadelphia, Johns Hopkins University and the State University of New
York, Buffalo) and abroad, in Germany and Japan.
About The Children's Hospital of Philadelphia: The Children's Hospital
of Philadelphia was founded in 1855 as the nation's first pediatric
hospital. Through its long-standing commitment to providing exceptional
patient care, training new generations of pediatric healthcare
professionals and pioneering major research initiatives, Children's
Hospital has fostered many discoveries that have benefited children
worldwide. Its pediatric research program is among the largest in the
country, ranking third in National Institutes of Health funding. In
addition, its unique family-centered care and public service programs have
brought the 430-bed hospital recognition as a leading advocate for children
and adolescents. For more information, visit http://www.chop.edu.
Contact: Rachel Salis-Silverman
Phone: (267) 426-6063
Salis@email.chop.edu
SOURCE The Children's Hospital of Philadelphia
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Related links:
http://www.chop.edu
CONTACT:
Rachel Salis-Silverman of The Children's
Hospital of Philadelphia, +1-267-426-6063, salis@email.chop.edu
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