Mir-217 promotes inflammation and fibrosis in high glucose cultured rat glomerular mesangial cells via Sirt1/HIF-1α signaling pathway.

BACKGROUND: Silent information regulator 1 (Sirt1) plays a protective role in kidney. Sirt1 suppresses activation of hypoxia-inducible factor-1 alpha (HIF-1α), with MircroRNA-217 (Mir-217) being closely related to Sirt1. The relationship of Sirt1, HIF-1α and Mir-217, however, has never been reported in high glucose cultured rat glomerular mesangial cells (RMCs). Thus, we explored the role of Mir-217 on inflammation and fibrosis in RMCs cultured with high glucose in vitro through Sirt1/HIF-1α signaling pathway.

METHODS: Rat glomerular mesangial cells were pre-incubated with Sirt1 activator Resveratrol prior to high glucose treatment. Furthermore the cells were transiently transfected with Sirt1 small interfering RNA (siRNA), HIF-1α siRNA and Mir-217 inhibitor using Lipofectamine 2000. Real-time PCR was used to analyse the expression of Mir-217, Sirt1 mRNA and HIF-1α mRNA; Western Blot was used to observe protein expression of Sirt1, HIF-1α, connective tissue growth factor, endothelin-1 and fibronectin; enzyme-linked immunosorbent assay was used to detect protein expression of transforming growth factor-β1 and vascular endothelial growth factor.

RESULTS: High glucose increased Mir-217 expression. High glucose decreased Sirt1 expression, accompanied by the increased HIF-1α expression and then promoted inflammation and fibrosis. In addition, Mir-217 gene silencing or Resveratrol could suppress the expression of HIF-1α, which in turn restrained inflammation and fibrosis in rat glomerular mesangial cells cultured with high glucose.

CONCLUSION: This study clarified the role of Mir-217 in high glucose cultured rat glomerular mesangial cells through Sirt1/HIF-1α signaling pathway and provided new therapeutic targets for diabetic nephropathy. Copyright © 2016 John Wiley & Sons, Ltd.