Smooth muscle cell migration stimulated by interleukin 6 is associated with cytoskeletal reorganization

Abstract

Background. Interleukin 6 (IL-6) is elevated in the arterial wall in atherosclerosis and restenosis after angioplasty. An important contributor to these pathologies is migration of vascular smooth muscle cells (VSMC), which is often associated with cytoskeletal reorganization initiated by growth factors and chemokines. We recently reported that IL-6 stimulated migration of VSMC. Here, we examined the cytoskeleton of VSMC and cytoskeletal associated proteins to determine potential mechanisms associated with IL-6 induced migration. Materials and methods. Studies were performed in VSMC cultured from rat aortas. Results. IL-6 significantly stimulated VSMC migration. IL-6 induced actin polymerization, and tyrosine phosphorylation of focal adhesion-associated cytoskeletal proteins including focal adhesion kinase (FAK) and paxillin. Cytochalasin D, an inhibitor of actin polymerization, blocked phosphorylation of FAK and paxillin as well as cell motility induced by the cytokine. Conclusions. Collectively, these data demonstrate for the first time that IL-6 stimulates VSMC motility which correlated with induction of actin cytoskeletal reorganization and tyrosine phosphorylation of FAK and paxillin.