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WWW:     http://www.newswise.com/articles/2001/9/MASLIAH2.UCD.html
Source:    University of California, San Diego
Date:        25-Sep-2001

Alzheimer's and Parkinson's Proteins Create a Destructive Team

The proteins associated with Alzheimer's disease and Parkinson's disease
interact to enhance each other's distinct degenerative effects, indicating
that therapies blocking the production or accumulation of either protein may
have broader benefits than previously thought, researchers report in the
September 25 Proceedings of the National Academy of Sciences, published
electronically.

Alzheimer's disease and Parkinson's disease are distinct neurological
disorders, but up to one-third of Alzheimer's patient develop Parkinson's,
and some Parkinson's patient develop signs of Alzheimer's.

To explore possible connections between the two diseases, scientists from
UCSD's departments of neurosciences and pathology, and from the Gladstone
Institute of Neurological Diseases and the UCSF department of neurology,
developed strains of transgenic mice that produce two human proteins, human
amyloid precursor protein (hAPP) and human alpha-synuclein (hSYN), which are
known to accumulate in Alzheimer's and Parkinson's, respectively.

Mice that produced one of the proteins developed the symptoms of the
respective disease. But when both proteins were produced in the same mouse,
the Alzheimer's-like symptoms of the hAPP mice--degeneration of particular
classes of brain cells, impaired ablity to learn--were exacerbated by the
production of hSYN. The Parkinson-like motor deficits of the hSYN mice
developed sooner in the mice that also expressed hAPP.

In addition, a metabolic breakdown product of hAPP, called Abeta, enhanced
the accumulation of hSYN in brain cells, indicating a possible mechanism for
the synergistic effects that were observed. Results of the study also
clarify the underlying mechanisms that destroy the cognitive and motor
functions of Alzheimer's patients who also develop Parkinson's.

Because these proteins interact to accelerate and exacerbate the symptoms of
their respective diseases, drugs aimed at preventing the accumulation of
hAPP or hSYN could benefit a wider spectrum of neurodegenerative disorders
than previously thought, the scientists speculate.

This work was conducted by Eliezer Masliah of UCSD, Lennart Mucke of the
Gladstone Institute of Neurological Disease at UCSF, and Edward Rockenstein,
Isaac Veinbergs, Yutaka Sagara, Margaret Mallory and Makoto Hashimoto of
UCSD. The research was supported by the National Institutes of Health.

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