INTRODUCTION Muscle stem cells termed satellite cells are essential for muscle regeneration. A central question in many neuromuscular disorders is why satellite cells are unable to prevent progressive muscle wasting. We have analyzed muscle fiber pathology and the satellite cell response in Pompe disease, a metabolic myopathy caused by acid alpha-glucosidase deficiency and lysosomal glycogen ac...

Previously, in an attempt to isolate stem cells that would be capable of regenerating injured skeletal muscle, we cultured cells derived from muscle, non-adherently, in serum-free media. As a result of the culture conditions used, these cells formed spheres, and thus were referred to as myospheres. It was found that myosphere-derived cells expressed Sca-1, a marker that is not typically associa...

Some patients with soft-tissue sarcoma (STS) report a history of injury at the site of their tumor. Although this phenomenon is widely reported, there are relatively few experimental systems that have directly assessed the role of injury in sarcoma formation. We recently described a mouse model of STS whereby p53 is deleted and oncogenic Kras is activated in muscle satellite cells via a Pax7(Cr...

We investigated the cellular and molecular bases for the promotion of muscle development and growth by temperature manipulations (TMs) during late-term chick embryogenesis. We show that incubation at 39.5 degrees C (increase of 1.7 degrees C from normal conditions) from embryonic days 16 to 18 (E16 to E18) for 3 or 6 h daily increased diameter of myofibers as of day 13 of age and enhanced absol...

Satellite cells (SC) are essential for skeletal muscle growth and repair. Because sarcopenia is associated with type II muscle fiber atrophy, we hypothesized that SC content is specifically reduced in the type II fibers in the elderly. A total of eight elderly (E; 76 +/- 1 yr) and eight young (Y; 20 +/- 1 yr) healthy males were selected. Muscle biopsies were collected from the vastus lateralis ...

We show that muscle satellite cells, traditionally considered as committed myogenic precursors, are comprised of Pax7-expressing progenitors that preserve a mesenchymal repertoire extending beyond a mere myogenic potential. Mouse satellite cells from freshly isolated single myofibers, cultured individually in serum-rich growth medium, produced myogenic and non-myogenic clones. Only the myogenic...