Figure 3

Matrix rigidity promotes epithelial-myofibroblast transition. (A) Immunofluorescence staining for actin, E-cadherin, and αSMA for primary alveolar type II cells cultured on fibronectin-coated polyacrylamide gels of varying rigidity or on fibronectin (Fn) or laminin (Ln) coated glass. The alveolar epithelial cells undergo EMT on rigid substrata. Panel (A) is from Brown et al, 2013 [147]. (B) Schematic depicting the activation of TGFβ from the latent complex. Adapted from Wells, 2013 [151]. Epithelial cells cultured on stiff matrices exhibit increased contractility thus enabling release of TGFβ from its latent complex thereby increasing the amount of active TGFβ accessible to bind to cell surface receptors.