Fig. 6.

Summary of proposed functional roles of small EVs from human tendon and muscle cells in tissue homeostasis. In tendon, tendon fibroblasts produce EVs (TenX), which act through autocrine or paracrine signalling to induce type I collagen expression, synthesis and assembly into the ECM. In skeletal muscle, EVs produced by myoblast progenitors (satellite cells, activated satellite cells) and myofibers (MyoX) regulate myoblast differentiation and myofibrillogenesis. There are EVs that are produced by muscle fibroblasts (FibX), which also help regulate myoblast differentiation but they also regulate the homeostasis of the basement membrane enveloping the myofibers and the fine collagen network of the endomysium