Repairing skeletal muscle: regenerative potential of skeletal muscle stem cells

Abstract

Skeletal muscle damaged by injury or by degenerative diseases such as muscular dystrophy is able to regenerate new muscle fibers. Regeneration mainly depends upon satellite cells, myogenic progenitors localized between the basal lamina and the muscle fiber membrane. However, other cell types outside the basal lamina, such as pericytes, also have myogenic potency. Here, we discuss the main properties of satellite cells and other myogenic progenitors as well as recent efforts to obtain myogenic cells from pluripotent stem cells for patient-tailored cell therapy. Clinical trials utilizing these cells to treat muscular dystrophies, heart failure, and stress urinary incontinence are also briefly outlined.

Figure 1. Asymmetric cell division during activation of SCs.

This is a drawing representing the anatomy of a muscle fiber with adjacent small vessels. SCs and other myogenic cells (pericytes and hematopoietic, endothelial, and interstitial cells) are depicted. SC activation in vivo is followed by an asymmetric division, with Pax7, MyoD, and Myf5 being expressed in differentiating cells and Pax7 in cells returning to quiescence in order to maintain a pool of progenitors (25, 41).

Figure 2. Derivation of different stem cells for possible use in skeletal muscle regeneration.

The figure shows a flow chart with the sources of different myogenic stem cells. The possibility of deriving the same cells from a reprogrammed cell of the dermis is also outlined (blue boxes and arrows). Once obtained, the stem cells can be characterized, expanded, genetically corrected, and transplanted.