Silencing of gelatinase expression delays myoblast differentiation in vitro.

ABSTRACT

Skeletal muscle growth and regeneration relies on the activation of muscle specific stem cells, that is, satellite cells. The activation and differentiation of satellite cells into myoblasts, as well as their migration, proliferation, and fusion of mononuclear myoblasts into a functional multi-nucleated muscle fiber, are associated with extracellular matrix (ECM) protein synthesis and degradation. The extracellular environment is dynamically adapting to the changes accompanying skeletal muscle growth or repair. Enzymes engaged in many biological processes that involve ECM remodeling are matrix metalloproteinases (MMPs). Among metalloproteinases crucial for skeletal muscles are two gelatinases-MMP-9 and MMP-2. In the current study we test the effect of silencing the MMP-9 and MMP-2 expression on the proliferation and differentiation of in vitro cultured skeletal muscle myoblasts. We show that downregulating gelatinase MMP-9 expression results in a delayed myoblast differentiation.