1. Adipocyte-derived factors impair insulin signaling in differentiated human vascular smooth muscle cells via the upregulation of miR-143.
- Author
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Blumensatt M, Wronkowitz N, Wiza C, Cramer A, Mueller H, Rabelink MJ, Hoeben RC, Eckel J, Sell H, and Ouwens DM
- Subjects
- Adipocytes cytology, Adult, Blotting, Western, Cell Differentiation drug effects, Cells, Cultured, Culture Media, Conditioned metabolism, Female, HEK293 Cells, Humans, Insulin metabolism, Middle Aged, Muscle, Smooth, Vascular cytology, Myocytes, Smooth Muscle cytology, Myocytes, Smooth Muscle metabolism, Phosphorylation drug effects, RNA Interference, Receptors, Steroid genetics, Receptors, Steroid metabolism, Reverse Transcriptase Polymerase Chain Reaction, Signal Transduction drug effects, Smad2 Protein genetics, Smad2 Protein metabolism, Up-Regulation drug effects, p38 Mitogen-Activated Protein Kinases genetics, p38 Mitogen-Activated Protein Kinases metabolism, Oxysterol Binding Proteins, Adipocytes metabolism, Culture Media, Conditioned pharmacology, Insulin pharmacology, MicroRNAs genetics, Myocytes, Smooth Muscle drug effects
- 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., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2014
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