The Mechanical and Biochemical Environment Controls Cellular Differentiation During Muscle Regeneration

Abstract

Urodele amphibians like the newt, are able to completely regenerate lost organs and appendages without scarring. Differentiated tissues are considered a reservoir for uncommitted blastema cells that participate in the regeneration of the lost structure. To determine the influence of the extracellular matrix (ECM) on the recruitment of progenitor cells from the skeletal muscle, we immunohistochemically mapped the limb in 3D and found that a transitional ECM rich in hyaluronic acid (HA), tenascin-C (TN) and fibronectin (FN) is dynamically expressed during the early stages of regeneration [1]. Functional in vitro testing of different ECM components on primary muscle cells revealed that HA and TN support myoblast migration, inhibit differentiation and enhance the fragmentation of multinucleate myotubes and production of viable mononucleate myoblasts, cellular behaviors necessary for blastema formation [1]. In contrast, myoblasts plated on matrices that mimic ECM around differentiated muscle (FN, Matrigel and laminin) induced both proliferation and fusion.