Human mesenchymal stem cells express a myofibroblastic phenotype in vitro

Abstract

There is emerging evidence to suggest that cardiac myofibroblasts (CMyfbs) participating in cardiac fibrosis represent a heterogeneous population in origin. We hypothesized that bone marrow derived mesenchymal stem cells (MSCs) readily adopt a myofibroblastic phenotype in culture. We assessed and compared human primary MSCs and human CMyfbs with respect to their phenotypic and functional characteristics by examining their gene expression profile, ability to contract collagen gels, and ability to synthesize collagen. We also examined the role of non-muscle myosin II (NMMII) in modulating the myofibroblast function using siRNA and blebbistatin to inhibit NMMII activity. The data revealed that MSCs adopt a myofibroblastic phenotype in culture and demonstrate the capability to contract collagen gels and synthesize collagen similar to human CMyfbs. Inhibition of NMMII activity with blebbistatin completely inhibits gel contractility without affecting cell viability. Thus, MSCs exhibit similar physiological and functional characteristics as CMyfbs, and may contribute to cardiac fibrosis.