脂肪细胞衍生因子通过上调miR-143损害分化的人血管平滑肌细胞中的胰岛素信号传导。

Adipocyte-derived factors impair insulin signaling in differentiated human vascular smooth muscle cells via the upregulation of miR-143.

作者信息

Blumensatt Marcel, Wronkowitz Nina, Wiza Claudia, Cramer Andrea, Mueller Heidi, Rabelink Martijn J, Hoeben Rob C, Eckel Juergen, Sell Henrike, Ouwens D Margriet

机构信息

Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Duesseldorf, Germany.

Paul-Langerhans-Group for Integrative Physiology, German Diabetes Center, Duesseldorf, Germany.

出版信息

Biochim Biophys Acta. 2014 Feb;1842(2):275-83. doi: 10.1016/j.bbadis.2013.12.001. Epub 2013 Dec 9.

Abstract

Cardiovascular complications are common in patients with type 2 diabetes. Adipokines have been implicated in the induction of proliferative and pro-atherogenic alterations in human vascular smooth muscle cells (hVSMC). Other reports demonstrated the importance of the miRNA cluster miR-143/145 in the regulation of VSMC homeostasis and insulin sensitivity. Here we investigated whether the detrimental effects of adipokines on hVSMC function could be ascribed to alterations in miR-143/145 expression. The exposure of hVSMC to conditioned media (CM) from primary human subcutaneous adipocytes increased the expression of smooth muscle α-actin (SMA), and the miR-143/145 cluster, but markedly impaired the insulin-mediated phosphorylation of Akt and its substrate endothelial nitric oxide synthase (eNOS). Furthermore, CM promoted the phosphorylation of SMAD2 and p38, which have both been linked to miR-143/145 induction. Accordingly, the induction of miR-143/145 as well as the inhibition of insulin-mediated Akt- and eNOS-phosphorylation was prevented when hVSMC were treated with pharmacological inhibitors for Alk-4/5/7 and p38 before the addition of CM. The transfection of hVSMC with precursor miR-143, but not with precursor miR-145, resulted in impaired insulin-mediated phosphorylation of Akt and eNOS. This inhibition of insulin signaling by CM and miR-143 is associated with a reduction in the expression of the oxysterol-binding protein-related protein 8 (ORP8). Finally, the knock-down of ORP8 resulted in impaired insulin-mediated phosphorylation of Akt in hVSMC. Thus, the detrimental effects of adipocyte-derived conditioned media on insulin action in primary hVSMC can be ascribed to the Alk- and p38-dependent induction of miR-143 and subsequent downregulation of ORP8.

摘要

心血管并发症在2型糖尿病患者中很常见。脂肪因子与人类血管平滑肌细胞(hVSMC)的增殖和促动脉粥样硬化改变的诱导有关。其他报告证明了miRNA簇miR-143/145在调节VSMC稳态和胰岛素敏感性方面的重要性。在这里,我们研究了脂肪因子对hVSMC功能的有害影响是否可归因于miR-143/145表达的改变。将hVSMC暴露于原代人皮下脂肪细胞的条件培养基(CM)中,可增加平滑肌α-肌动蛋白(SMA)和miR-143/145簇的表达,但显著损害胰岛素介导的Akt及其底物内皮型一氧化氮合酶(eNOS)的磷酸化。此外,CM促进了SMAD2和p38的磷酸化,这两者都与miR-143/145的诱导有关。因此,在添加CM之前,用Alk-4/5/7和p38的药理抑制剂处理hVSMC,可防止miR-143/145的诱导以及胰岛素介导的Akt和eNOS磷酸化的抑制。用前体miR-143转染hVSMC,但不用前体miR-145转染,会导致胰岛素介导的Akt和eNOS磷酸化受损。CM和miR-143对胰岛素信号的这种抑制与氧化固醇结合蛋白相关蛋白8(ORP8)表达的降低有关。最后,敲低ORP8导致hVSMC中胰岛素介导的Akt磷酸化受损。因此,脂肪细胞衍生的条件培养基对原代hVSMC中胰岛素作用的有害影响可归因于Alk和p38依赖性的miR-143诱导以及随后ORP8的下调。

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