MMP-14 in skeletal muscle repair.

MMP-14 (also known as MT1-MMP) is a membrane-bound collagenase and member of the Matrix Metalloprotease (MMP) family known to target a broad range of extracellular matrix (ECM) proteins. Remodelling of the ECM is of particular importance following skeletal muscle injury involving myofiber necrosis, when satellite cells are activated to facilitate myogenesis and regeneration. Myogenesis (broadly encompassed by the processes of satellite cell activation, proliferation, migration, differentiation and fusion) requires the myoblast to move either on or through a changing milieu of ECM components. The ECM composition, and especially the degree of fibrosis, influences ability of satellite cells to mediate a successful regenerative program. As a result, MMP activity is central to this regeneration; its activity increases following skeletal muscle injury, while inhibition of MMP reduces regeneration in this tissue. Besides its direct effect on matrix invasion, MMP-14 itself can affect this regeneration via activation of other MMPs (MMP-2, -9 and -13) as well as cytokines, chemokines and growth factors. Indeed recent research suggests that MMP-14 is necessary for the migration of human myoblasts into a collagen I matrix. Here we provide a current review on MMP-14 in the context of its role as a critical mediator of skeletal muscle regeneration.