Skeletal muscle contains a complex array of cell types. Among its principal components are multi-nucleated muscle fibers and muscle satellite cells -- cells located in close association with muscle fibers and containing precursors capable of giving rise to new muscle fibers.
"Our studies show that only the satellite cells, located near muscle fibers, can give rise to new muscle cells. Contrary to previous studies, precursor cells from bone marrow or other blood-forming tissues did not change their destiny to become muscle cells," said Amy J. Wagers, Ph.D., Investigator in the Developmental and Stem Cell Biology Research Section at Joslin Diabetes Center and Assistant Professor of Pathology at Harvard Medical School, the principal investigator of a study published in the Nov. 12 edition of Cell. The research, which originated in the laboratory of Irving L. Weissman, M.D., at Stanford University, now continues at Joslin Diabetes Center in Boston. Over the past few years, several research groups have reported that stem cells found in the bone marrow could repair damaged muscle cells. This had raised hopes that the well-characterized blood-forming stem cells could be used therapeutically to treat muscular diseases. Dr. Wagers' work disputes these past results, showing that bone marrow stem cells do move to the muscle but don't regularly participate in repairing muscle damage.
In the first part of the Dr. Wagers' latest study, the researchers isolated muscle satellite cells from mice and marked them with a substance that glows in fluorescent light. They also generated adult bone-marrow cells and blood-forming stem cells that carried the fluorescent markers. They then examined the capacity of these three different cell
Contact: Marjorie Dwyer
Joslin Diabetes Center