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Ed. Note: The following is a press
release from Rutgers University.
January 5, 2007 -- Uric acid is
commonly associated with the excruciatingly painful joint disease known as
gout, but it can also play a crucial role in the treatment of spinal cord
injury and other central nervous system disorders, such as stroke, multiple
sclerosis and Parkinson’s disease, according to Rutgers’ Bonnie Firestein.
Firestein, an associate professor of cell biology and neuroscience at
Rutgers, The State University of New Jersey, and her laboratory team have
reported their discovery in the Early View (online in advance of print)
version of the journal Glia.
"In spinal cord injury, as well as stroke, two kinds of damage can occur,"
Firestein explained. "First there is the physical damage, but this is
followed by secondary chemical damage to neurons [nerve cells] by compounds
released in response to the trauma. We have found that uric acid can promote
an early intervention step in combating this chemical damage through its
action on astroglial cells."
Astroglial cells or astrocytes are specialized cells that support neuron
function with nutrients and protective buffering.
In addition to the scientific achievement, the research study is a model for
student involvement and education. Among the co-authors, postdoctoral
associate Yangzhou Du is teaching Firestein more about astroglial cells,
while he is learning about neurons from her. Christopher Chen was a Henry
Rutgers Honors undergraduate student on the study, and Yuval Eisenberg, a
laboratory technician; both now attend medical school. Another student, Chia-Yi
Tseng is continuing her graduate studies in Firestein’s laboratory.
Uric acid’s effects on the health of neurons had been observed by other
researchers, but the mechanics of how it confers protection has remained a
mystery.
"It is interesting to note that people with gout never seem to develop
multiple sclerosis," Firestein said. "In animal models of multiple
sclerosis, the addition of uric acid reduces symptoms and improves
prognosis. The same is true for one type of Parkinson’s disease tested."
The Firestein team’s breakthrough studies revealed that uric acid can
stimulate astroglial cells to produce transporter proteins that carry
harmful compounds away from neurons in jeopardy of chemical damage. This
opens the door to identifying a unique drug target for new therapies.
Glutamate is a compound that under normal circumstances aids neurons in
transmitting signals for cognitive functions in the brain, such as learning
and memory. In the case of spinal cord injury or stroke where there is
physical cell damage, however, an excess of glutamate is released and it
accumulates around the remaining intact neurons, eventually choking them to
death.
When Firestein’s group added uric acid to a mixed culture of rat spinal cord
neurons and astroglial cells, the production of the glutamate transporter
EAAT-1 increased markedly. The challenge now is find the most effective
strategy for increasing the production of the transporter, using drug
therapies or other means.
Firestein said that a collaborative team of colleagues from Baylor College
of Medicine and the University of Rochester Medical Center has devised one
such strategy. With this team, Firestein will develop a line of stem cells
that has been modified to generate astrocytes that produce large quantities
of the EAAT-1 transporter. Adding these to an injury site, either alone or
in combination with uric acid, holds great potential, she said.
The study was supported by a grant from the New Jersey Commission on Spinal
Cord Research.
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