By Merritt McKinney
NEW YORK, Feb 18 (Reuters Health) -- Abnormal accumulation of a protein
normally found in the human brain may be responsible for neurodegenerative
disorders like Parkinson's disease, according to a new study in this week's
Science.
The protein, alpha-synuclein, "is normally produced in the brain but when
overexpressed, it may accumulate in the brain and lead to Alzheimer's and
Parkinson's," lead study author Dr. Eliezer Masliah of the University of
California San Diego in La Jolla told Reuters Health. In normal amounts, the
protein appears to play a role in communication between nerve cells, but in high
amounts, it "disrupts the function of (brain cells) and eventually kills them,"
he explained.
In order to study the role of the protein in neurodegenerative diseases,
Masliah and colleagues created mice that produced the human version of the
protein in their brains. The researchers noted several changes in the brains of
these mice that are similar to changes seen in human subjects with diseases that
affect the function of the brain. One of these was the formation of particles in
cells that resembled Lewy bodies, which are abnormal cell particles found in
parts of the brain affected by Alzheimer's and Parkinson's disease in humans.
Along with these changes, Masliah's team found that the mice also
developed weak muscles and tremors. "The movements of the mice decreased... limb
strength is decreased and we see tremors in their body," Masliah said. He noted
that these activities are controlled by areas of brain that appear to be damaged
by the accumulated protein, and that people with Parkinson's display similar
characteristics.
This research may lead to treatments for Parkinson's and Alzheimer's
disease, Masliah commented. But he noted that because the protein is normally
found in human brains and presumably plays a role in important functions, a drug
that blocks the protein entirely would not be useful. "We need something that
blocks the (accumulation) of the protein, but not something that blocks the
function of the protein," he said.
