Abstract 3264: N-cadherin Mediated Mechanosensitivity and Its Role in Myocyte Cytoskeleton Remodeling
Cell-matrix and cell-cell adhesions are crucial in maintaining the structural integrity and contractile function of cardiac myocytes. Changes or disruptions to these adhesions can have adverse affects on myocyte shape and cytoskeletal architecture giving rise to mechanical and electrical dyssynchrony. Nearly all studies in mechanobiology have focused on attachment of sub confluent cells to ECM ligands. It has not been established whether N-Cadherin (N-Cad) is a mechanosensor in cardiac myocytes. To test the hypothesis that N-Cad is directly involved in the mechanotransduction process, neonatal ventricular myocytes were plated on a model gel system of varying stiffness, functionalized with N-Cad (Fig. 1B⇓) and as control Collagen Type I & Fibronectin (Fig. 1A⇓). Cells were fixed and stained for F-actin, sarcomeric α-actinin, vinculin and beta catenin. On soft (300 Pa) N-Cad gels myocytes did not develop F-actin fibers and were lacking in sarcomeric organization. At physiological tissue stiffness (15 kPa), cells showed striated F-actin and organized myofibrils, on stiff surfaces (60 kPa), cells displayed prominent F-actin filaments without striations and disorganized myofibrils. The changes in cellular spreading and myofibrillar architecture (Fig. 1 B&C⇓) as a function of stiffness suggests that N-Cad mediated adhesions are capable, at a global level, to remodel the cytoskeleton architecture. These studies show, for the first time, that changes in N-Cad mediated traction forces can remodel the cytoskeletal architecture and the results have broad implications for engineering tissue constructs and creating a conducive micro environment for regenerative therapies.