CHANGES IN SKELETAL MUSCLE SATELLITE CELLS DURING AGING

Senile muscle atrophy represents one of the major problems associated with
aging and is characterized by loss of strength and muscle mass. These
changes restrict the mobility and independence of a growing segment of our
society. This project will probe the cellular and molecular changes that occur
during muscle aging. In particular, the function of skeletal muscle
satellite cells will be evaluated. Satellite cells are the myogenic
precursor cells that persist in muscle throughout life and function by
adding new nuclei to existing muscle fibers during muscle hypertrophy and
by regenerating new fibers following injury. Their ability to proliferate
and differentiate in response to three important regulatory protein growth
factors, or hormones, is being studied. These hormones are the two
insulin-like growth factors (somatomedins) and fibroblast growth factor.
In vitro techniques have been devised for monitoring the effects of growth
factors on the proliferation and differentiation of cultured satellite
cells, and these techniques will be employed to study the normal control of
satellite cell activity. In addition, age-related changes in the ability
of satellite cells to respond to these growth factors and changes in their
growth factor receptor characteristics during aging will be examined. This
research program is designed to provide fundamental insights into the
cellular and molecular mechanisms of muscle aging with the ultimate goal of
contributing toward the alleviation of problems associated with senile
muscle atrophy.