Down-regulated miR-145 rescues insulin resistance in endothelial cells

Abstract

Background: MiR-145 is involved in insulin resistance (IR) in liver cells, but its effects in human umbilical vein endothelial cells (HUVECs) induced by IR remains unclear. This study took this as the starting point, aiming to find a potential target for the treatment of related disease. Methods: HUVECs were respectively treated with glucose of 15, 30, 45 mmol/L, or insulin of 1, 2, 3, 4, 5 μmol/L on the basis of high-glucose (33.3 mmol/L). MiR-145 mimics and miR-145 inhibitor were severally transfected into HUVECs with or without IR (4 μmol/L insulin + high-glucose). Quantitative real-time polymerase chain reaction (qRT-PCR) assay determined the miR-145 expression in HUVECs after treatment and transfection. The glucose consumption and glycogen contents of cells were appraised by glucose oxidase-peroxidase and anthranone-sulfuric acid methods, respectively. The apoptotic rates were ascertained using the flow cytometry. The expressions of apoptosis-related indicators Bcl-2 and Bax were analyzed by western blot (WB) and qRT-PCR assays. Results: The expression of miR-145 was increased in IR models and incremental glucose concentrations. The glucose consumption and glycogen content were down-regulated in IR-induced HUVECs, which were enhanced by over-expressed miR-145 but reversed by down-regulation. Moreover, over-expression of miR-145 aggravated the apoptosis of IR-induced HUVECs, while the inhibition of miR-145 had a completely opposite effect. Accordingly, up-regulated miR-145 obviously reduced Bcl-2 level and enhanced Bax expression in IR models, which was contrary to the down-regulated miR-145. Conclusion: Down-regulated miR-145 rescued IR in endothelial cells, which might be a conceivable treatment for IR of endothelial cells.