article: cerebellum

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Treatment of Down Syndrome In Mice Restores Nerve Growth In Cerebellum

From s Hopkins Medicine http://tinyurl.com/dymx3

Researchers at s Hopkins restored the normal growth of specific

nerve cells in the cerebellum of mouse models of Down syndrome (DS) that

were stunted by this genetic condition. The cerebellum is the rear, lower

part of the brain that controls signals from the muscles to coordinate

balance and motor learning.

The finding is important, investigators say, because the cells rescued

by this treatment represent potential targets for future therapy in human

babies with DS. And it suggests that similar success for other DS-related

disruptions of brain growth, such as occurs in the hippocampus, could lead

to additional treatments - perhaps prenatally - that restore memory and the

ability to orient oneself in space.

DS is caused by an extra chromosome 21, a condition called trisomy - a

third copy of a chromosome in addition to the normal two copies. Children

with DS have a variety of abnormalities, such as slowed growth, abnormal

facial features and mental retardation. The brain is always small and has a

greatly reduced number of neurons.

A report on the Hopkins work with trisomic mice, led by H.

Reeves, Ph.D., professor in the Department of Physiology and the

McKusick-s Institute for Genetic Medicine at Hopkins, appears in the

January 24 issue of the Proceedings of the National Academy of Sciences

(PNAS).

Reeves and his team used an animal model of DS called the Ts65Dn

trisomic mouse to show that pre-nerve cells called granule cell precursors

(GCP) fail to grow correctly in response to stimulation by a natural

growth-triggering protein. This protein, called Sonic hedgehog (Shh),

normally activates the so-called Hedgehog pathway of signals in these cells.

These signals stimulate mitosis (cell division) and multiplication of the

cells in the growing, newborn brain, according to the researchers.

+ Full article here: http://tinyurl.com/dymx3