A news release from the University of Houston

RESEARCH MAY LEAD TO JUMP-STARTING DAMAGED NERVE CELLS
Results Hold Possibilities For Treating Parkinson’s and Lou Gehrig’s
Disease

HOUSTON, Jan. 18, 2002 – New research from University of Houston
scientists may lead to techniques for jump-starting the faulty
"wiring" in damaged nerve cells, and suggests possible avenues for
treating spinal cord injuries, Parkinson’s disease and amyotrophic
lateral sclerosis, or ALS, also known as Lou Gehrig’s disease.

University of Houston scientists studying how spinal nerve cells in
chicken embryos develop and function have found that chemicals called
growth factors play a key role in regulating how embryonic nerve
cells acquire the ability to start processing information.

"In some cases, when nerves are damaged or succumb to
neurodegenerative diseases such as ALS and Parkinson’s, they don’t
die, but they quit working and may actually revert to an immature
embryonic-like state," says Stuart Dryer, a neuroscientist in the
department of biology and biochemistry at UH.

Embryonic nerve cells are able to fire electrical impulses shortly
after the cells have divided for the last time – after they are
"born." But these impulses are extremely generic, and not necessarily
specialized for the kind of information the cell is going to
eventually process, Dryer says.

"Initially, the cells are becoming connected, like the individual
circuit elements in a computer, and the message that gets through is
one that says ‘I’m hooking up’ rather than ‘I’m processing
information’," Dryer says. The developing embryonic cells must
somehow acquire the ability to discharge and route electrical
impulses in a coordinated, highly specialized fashion.

"If damaged cells have indeed entered a kind of immature state,
perhaps we can kick-start them back to their proper function using
the natural pathways embryonic cells take to become fully functioning
nerve cells," Dryer says.

Nerve cells, or neurons, connect to each other in complex networks,
carrying electrical and chemical signals through the body to other
cells, or "target" tissues, allowing muscles to move and the brain to
think.

Dryer’s research shows that chemicals – called growth factors – may
be the trigger that allows embryonic nerve cells to become
specialized. Growth factors secreted by the target tissue signal the
embryonic nerve cells to make their own set of chemicals, called ion
channel proteins. These ion channel proteins then attach to certain
places on the nerve cell’s membrane, where they "channel"
electrically charged particles called ions in and out of the neuron.
This results in the cells becoming able to conduct electrical
impulses.

In their most recent study, Dryer and post-doctoral fellow Miguel
Martin-Caraballo found that as the number of ion channels increases,
the electrical properties of the developing neuron change.

Dryer found that once a certain density of ion channels in the
embryonic nerve cell are in place, the cell exhibits mature
electrical behavior, functioning with the specialized electrical
patterns needed "to do what it’s supposed to do," he says. "It is the
growth factors associated with the target tissue that spur the ion
channel formation. This study is the first attempt to look at how
growth factors control the electrical properties of embryonic spinal
motoneurons."

Dryer’s study is published in the Jan. 1 issue of the Journal of
Neuroscience. It was funded by the Muscular Dystrophy Association and
the National Institutes of Health. More information on Dryer’s
research can be found at
http://www.bchs.uh.edu/People/Dryer/Dryer.html.

Since 1988, Dryer has been investigating what happens during the
development of embryonic neurons that allows these cells to become
functionally mature. Understanding these mechanisms may lead to
treatments for jump-starting, or rewiring, damaged nerve cells and
restoring their function, he says.

"The growth factor molecules secreted by muscle tissue and other
nerve cells seem to be the signal that says ‘change your electrical
properties to become mature’," Dryer says. His research also suggests
that the formation of spaces, or synapses, between neurons, and
between neurons and their target tissue, is crucial for neurons to
become functionally mature, and that growth factors are involved in
synapse formation as well.

"The very refined electrical impulses occur after the cells form
their synaptic connections, after they hook
up with other cells," he says.

Growth molecules have been used in clinical trials to treat ALS, with
mixed results, Dryer says. "In some of
these cases, they may have halted the progression of the disease, but
the patients’ symptoms didn’t get
better. Although the nerve cells lived, they may have reverted to an
immature state. Perhaps the cells need
some other growth factor to jump-start them back into electrical
action."

Similarly, some Parkinson’s patients have been treated by having
embryonic stem cells injected into their
brains. "When this approach works, the results can be dramatic, but
usually it doesn’t work. Why?" Dryer
asks. "One possibility is that because they are embryonic cells, they
may wire up OK, but perhaps they need
another switch that tells them to become not just functional, but
specialized with certain electrical
behavior. Just because they’re in the brain’s environment there’s no
reason to believe they will
automatically acquire the ability to become specialized."

About the University of Houston

The University of Houston, Texas’ premier metropolitan research and
teaching institution, is home to more than 40 research centers and
institutes and sponsors more than 300 partnerships with corporate,
civic and governmental entities. UH, the most diverse research
university in the country, stands at the forefront of education,
research and service with more than 32,000 students.

For more information about UH visit the university’s ‘Newsroom’ at
www.uh.edu/admin/media/newsroom.

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