Adipocyte-Derived Plasma Protein Adiponectin Acts as a Platelet-Derived Growth Factor-BB–Binding Protein and Regulates Growth Factor–Induced Common Postreceptor Signal in Vascular Smooth Muscle Cell

Background— Vascular smooth muscle cell proliferation plays an important role in the development of atherosclerosis. We previously reported that adiponectin, an adipocyte-specific plasma protein, accumulated in the human injured artery and suppressed endothelial inflammatory response as well as macrophage-to-foam cell transformation. The present study investigated the effects of adiponectin on proliferation and migration of human aortic smooth muscle cells (HASMCs). Methods and Results— HASMC proliferation was estimated by [3H] thymidine uptake and cell number. Cell migration assay was performed using a Boyden chamber. Physiological concentrations of adiponectin significantly suppressed both proliferation and migration of HASMCs stimulated with platelet-derived growth factor (PDGF)-BB. Adiponectin specifically bound to 125I-PDGF-BB and significantly inhibited the association of 125I-PDGF-BB with HASMCs, but no effects were observed on the binding of 125I-PDGF-AA or 125I-heparin–binding epidermal growth fa...