Adiponectin attenuates the osteoblastic differentiation of vascular smooth muscle cells through the AMPK/mTOR pathway

Vascular calcification is common in patients with peripheral artery diseases and coronary artery diseases. The osteoblastic differentiation of vascular smooth muscle cells (VSMCs) contributes significantly to vascular calcification. Adiponectin has been demonstrated to exert a protective effect in osteoblastic differentiation of VSMCs through regulating mTOR activity. However, the upstream and downstream signaling molecules of adiponectin-regulated mTOR signaling have not been identified in VSMCs with osteoblastic differentiation. In this study, the VSMC differentiation model was established by beta-glycerophosphate (beta-GP) induction. The mineralization was identified by Alizarin Red S staining. Protein expression and phosphorylation were detected by Western blot or immunofluorescence. Adiponectin attenuated osteoblastic differentiation and mineralization of beta-GP-treated VSMCs. Adiponectin inhibited osteoblastic differentiation of VSMCs through increasing the level of p-AMPK alpha. Pretreatment of VSMCs with AMPK inhibitor blocked while AMPK activator enhanced the effect of adiponectin on osteoblastic differentiation of VSMCs. Adiponectin upregulated TSC2 expression and downregulated mTOR and S6K1 phosphorylation in p-GP-treated VSMCs. Adiponectin treatment significantly attenuates the osteoblastic differentiation and calcification of VSMCs through modulation of AMPK TSC2 mTOR S6K1 signal pathway. (c) 2014 Elsevier Inc. All rights reserved.

血管钙化在周围动脉疾病和冠状动脉疾病患者中很常见。血管平滑肌细胞（VSMCs）的成骨分化对血管钙化有重要作用。脂联素已被证明可通过调节mTOR活性对VSMCs的成骨分化产生保护作用。然而，在发生成骨分化的VSMCs中，脂联素调节的mTOR信号的上下游信号分子尚未确定。在本研究中，通过β - 甘油磷酸酯（β - GP）诱导建立了VSMC分化模型。通过茜素红S染色鉴定矿化情况。通过蛋白质印迹法或免疫荧光检测蛋白质表达和磷酸化。脂联素减轻了β - GP处理的VSMCs的成骨分化和矿化。脂联素通过提高p - AMPKα水平抑制VSMCs的成骨分化。用AMPK抑制剂预处理VSMCs可阻断脂联素对VSMCs成骨分化的作用，而AMPK激活剂则增强该作用。脂联素上调β - GP处理的VSMCs中TSC2的表达，并下调mTOR和S6K1的磷酸化。脂联素治疗通过调节AMPK - TSC2 - mTOR - S6K1信号通路显著减轻VSMCs的成骨分化和钙化。（c）2014爱思唯尔公司。保留所有权利。