American Physiological Society, Journal of Applied Physiology, 5(113), p. 707-713, 2012
DOI: 10.1152/japplphysiol.00300.2012
Full text: Unavailable
Sphingosine 1-phosphate is a bioactive lipid that modulates skeletal muscle growth through its interaction with specific receptors localized in the cell membrane of muscle fibers and satellite cells. This study analyzes the role of S1P2receptor during in vivo regeneration of soleus muscle in two models of S1P2deficiency: the S1P2-null mouse and wild-type mice systemically treated with the S1P2receptor antagonist JTE-013. To stimulate regeneration, muscle degeneration was induced by injecting into soleus muscle the myotoxic drug notexin. Both ablation of S1P2receptor and its functional inactivation delayed regeneration of soleus muscle. The exogenous supplementation of S1P or its removal, by a specific antibody, two conditions known to stimulate or inhibit, respectively, soleus muscle regeneration, were without effects when the S1P2receptor was absent or inactive. The delayed regeneration was associated with a lower level of myogenin, a muscle differentiation marker, and reduced phosphorylation of Akt, a key marker of muscle growth. Consistently, silencing of S1P2receptor abrogated the pro-myogenic action of S1P in satellite cells, paralleled by low levels of the myogenic transcription factor myogenin. The study indicates that S1P2receptor plays a key role in the early phases of muscle regeneration by sustaining differentiation and growth of new-forming myofibers.