Alpha-SMA assay as a key marker of differentiated myofibroblasts and tissue fibrosis
This cell-based assay is designed to measure the expression level of α-SMA (α-Smooth Muscle Actin, also known as ACTA2), a key marker of differentiated myofibroblasts and tissue fibrosis.
After tissue injury, TGF-β locally released by inflammatory cells activates resident fibroblasts or quiescent HSCs (hepatic stellate cells). This leads to their differentiation into contractile and secretory myofibroblasts, whose role is to migrate into the damaged tissue and synthetize ECM (extracellular matrix) components to repair the wound.
Myofibroblasts are characterized by de novo expression of α-SMA, which is incorporated into actin stress fibers and confers a high contractile activity to the cells.
Chronic tissue injury and inflammation lead to persistent de novo formation of myofibroblasts (α-SMA+) and excessive contraction and deposition of ECM, eventually leading to tissue fibrosis (hepatic, pulmonary, renal, cardiac or dermal). Inhibiting myofibroblast differentiation is therefore a promising therapeutic strategy to treat fibrotic disorders.