Modulation of Caspase Activity Regulates Skeletal Muscle Regeneration and Function in Response to Vasopressin and Tumor Necrosis Factor
Figure 9
Model for the proposed mechanism underlying the differential effects exerted by TNF and AVP on skeletal muscle regeneration and function.
A) TNF enhances caspase activation in regenerating muscle through PW1 and concomitant downregulation of Hsp70 expression. The latter binds to PW1 and diminishes caspase activation in myogenic cells. The reduced extent of regeneration and the delayed fiber growth result in poor muscle performance. B) When combined with TNF, AVP increases Hsp70 expression, thereby yielding a caspase activity level that is comparable to that of the control. This determines an abundant formation and growth of regenerating fibers, which in turn results in a recovered functional output of the injured muscle.