October 24, 2001
Mice with Parkinson's Disease Reveal Therapy Clues
By Keith Mulvihill
NEW YORK (Reuters Health) - Scientists report that they have
discovered a protein that may prove useful in the fight against
Parkinson's disease.
Working with genetically altered mice, lead investigator Dr. Eliezer
Masliah and colleagues at the University of California, San Diego,
studied what happens when the balance between naturally occurring
brain proteins goes awry and produces effects similar to those that
occur in Parkinson's patients.
Alpha-synuclein, a naturally occurring protein in the brain and a key
player in Parkinson's disease, is found in deposits called Lewy bodies
that build up in the brains of all patients with the disease, Masliah
explained in an interview with Reuters Health.
Experiments with mice found that a second protein, called
beta-synuclein, somehow counteracts the effects of alpha-synuclein,
according to Masliah.
Mice that were genetically modified to overproduce both forms of
synuclein did not develop the Lewy bodies or symptoms of Parkinson's
disease. However, mice that only overproduced alpha-synuclein did
develop the telltale protein clumps associated with Parkinson's disease,
according to the report in the October 25th issue of the journal Neuron.
These latest findings ``emphasize the idea that there is a balance
between (these naturally occurring) proteins. If the balance is lost,
Parkinson's disease can develop,'' Masliah said.
Normally, the two proteins work in concert in the brain and protein
clumps of alpha-synuclein do not form. But if something goes wrong in
the relationship among these proteins, this could lay the groundwork for
the Lewy bodies seen in Parkinson's, he noted.
Masliah hopes that the discovery of beta-synuclein's role in thwarting
Parkinson's disease will help scientists to develop a drug that acts
like
the protein and stops the formation of the alpha-synuclein clumps.
Parkinson's disease is a progressive neurological disorder marked by
tremors, muscle rigidity, and balance and coordination problems. The
destruction of brain cells that produce the chemical dopamine underlies
these symptoms. These diseased cells are also marked by Lewy bodies.
But no one knows why the cells die or whether the Lewy bodies help
kill them.
Parkinson's--characterized by shaking and muscular rigidity--affects
from between 1 and 3 people per 1,000 worldwide, and is most
common in those over age 50.
SOURCE: Neuron 2001;32:213-223.
Copyright © 2001 Reuters Limited.
Copyright © 2001 Yahoo! Inc.
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Judith Richards, London, Ontario, Canada
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