Peking University, Beijing, China.
Acta Pharmacol Sin. 2010 Oct;31(10):1359-66. doi: 10.1038/aps.2010.89. Epub 2010 Aug 30.
To determine whether adrenomedullin (ADM) attenuates vascular calcification (VC) by inducing osteopontin (OPN) expression.
A VC model of rat aorta was induced with vitamin D3 plus nicotine (VDN), and vascular smooth muscle cell (VSMC) calcification was induced with beta-glycerophosphate. Von Kossa staining and alizarin red staining were assessed. Alkaline phosphatase (ALP) activity was measured. Immunohistochemical analysis was used to detect alpha-actin, while RT-PCR and Western blot analysis were used to quantify OPN expression.
Administration of ADM greatly reduced VC in VDN-treated aortas compared with controls, which was confirmed in calcified VSMCs. The decrease in alpha-actin expression was ameliorated by ADM both in vivo and in vitro. Moreover, mRNA and protein expression levels of OPN were significantly up-regulated in calcified aortas, and ADM increased OPN expression in calcified aortas. Furthermore, ADM up-regulated OPN expression in normal aortas and VSMCs. The ADM-mediated effects were similar to that of forskolin, which activates adenylyl cyclase; additionally, while the PKA inhibitor H89 and Ca²(+) chelator Fura-2 blocked the effect of ADM. However, the MEK/ERK inhibitor PD98509 had no effect on ADM induction of OPN mRNA expression. An OPN polyclonal antibody inhibited ADM-mediated attenuation of VC.
ADM up-regulates OPN expression and thus attenuates VC via PKA. ADM appears to be an endogenous cardiovascular protective peptide and may represent a new therapeutic target for VC treatment.
研究肾上腺髓质素(ADM)是否通过诱导骨桥蛋白(OPN)表达来抑制血管钙化(VC)。
用维生素 D3 加尼古丁(VDN)诱导大鼠主动脉 VC 模型,用β-甘油磷酸诱导血管平滑肌细胞(VSMC)钙化。通过 Von Kossa 染色和茜素红染色进行评估。测量碱性磷酸酶(ALP)活性。免疫组织化学分析检测α-肌动蛋白,同时通过 RT-PCR 和 Western blot 分析检测 OPN 表达。
与对照组相比,ADM 给药大大减少了 VDN 处理的主动脉中的 VC,这在钙化的 VSMC 中得到了证实。ADM 可改善体内和体外α-肌动蛋白表达的减少。此外,钙化主动脉中 OPN 的 mRNA 和蛋白表达水平显著上调,ADM 增加了钙化主动脉中的 OPN 表达。此外,ADM 上调了正常主动脉和 VSMC 中的 OPN 表达。ADM 的作用与激活腺苷酸环化酶的 forskolin 相似;此外,PKA 抑制剂 H89 和 Ca²(+)螯合剂 Fura-2 阻断了 ADM 的作用。然而,MEK/ERK 抑制剂 PD98509 对 ADM 诱导的 OPN mRNA 表达没有影响。OPN 多克隆抗体抑制了 ADM 介导的 VC 抑制作用。
ADM 通过 PKA 上调 OPN 表达,从而抑制 VC。ADM 似乎是一种内源性心血管保护肽,可能成为 VC 治疗的新靶点。