MicroRNA-148b influences high glucose-induced endoplasmic reticulum stress in rat mesangial cell by targeting AMPKα1

Abstract

Objective To observe the expression of microRNA-148b (miR-148b) induced by high glucose in rat mesangial cells, and to explore its effect on its target gene AMP-activated protein kinase α1 (AMPKα1) and extracellular matrix excretion. Methods Rat mesangial cells were divided into 3 groups: normal glucose (NG, 5.5 mmol/L glucose) group, hypertonic (MA, 5.5 mmol/L glucose+ 19.5 mmol/L mannitol) group and high-glucose (HG, 25.0 mmol/L glucose) group. MiR-148b expression was detected by real time PCR. Then miR-148b inhibitor was transfected to rat mesangial cells. Their protein expressions of AMPKα1, glucose regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), fibronectin (FN) and collagen Ⅳ were detected by Western blotting. The expression of AMPKα1 mRNA was detected by real time PCR. The expression of collagen Ⅳ was also detected by immunofluorescence. Results Compared with NG group, HG group showed up-regulated miR-148b expression, down-regulated AMPKα1 mRNA and protein expressions, and up-regulated CHOP, GRP78, collagen Ⅳ and FN expressions (all P<0.05). HG-induced mesangial cells with miR-148b inhibitor had up-regulated AMPKα1 mRNA and protein expressions, and down-regulated CHOP, GRP78, collagen Ⅳ, FN expressions as compared with HG-induced cells without miR-148b inhibitor (all P<0.05). Conclusions HG can up-regulate miR-148b expression and down-regulate AMPKα1 expression in rat mesangial cells, then activate endoplasmic reticulum stress to induce extracellular matrix excretion. MiR-148b inhibitor up-regulates AMPKα1 expression, inhibits endoplasmic reticulum stress and reduces extracellular matrix excretion. Key words: Diabetic nephropathies; Mesangial cells; MicroRNAs; Endoplasmic reticulum stress; AMP-activated protein kinases