Abated microRNA-21 attenuates high glucose-induced autophagy inhibition in rat mesangial cells by PTEN/Akt/mTOR pathway / 中华肾脏病杂志

ABSTRACT

Objective To investigate the effects of abated microRNA-21 (miRNA-21) on phosphatase and tensin homologue on chromosome ten protein (PTEN) and PI3K/Akt/mTOR pathway,as well as their further influence on the autophagy in high glucose (HG,25.0 mmol/L) induced rat glomerular mesangial cells.Methods MiRNA-21 inhibitor and negative control were transfected by liposome 2000 into rat glomerular mesangial cells (HBZY-1).The cells were divided into normal glucose (5.5 mmol/L) group,normal glucose + negative control group,normal glucose +miRNA-21 inhibitor group,HG group,HG+negative control group and HG+miRNA-21 inhibitor group.Cell proliferation and hypertrophy were assayed by MTT and the ratio of total protein to cell number respectively.The miRNA-21 expression was detected using real time PCR.The expressions of PTEN/ Akt/mTOR signaling signatures,autophagy-associated protein (p62 and LC3 Ⅱ) and collagen Ⅰ was detected by Western blotting and real time PCR.Autophagosomes were observed using electron microscopy.Results Compared with those in normal glucose group,in HG group cells had hypertrophy and proliferation,up-regulated miRNA-21 expression,and down-regulated PTEN protein and mRNA expressions (all P ＜ 0.01).Also there were and up-regulated p-Akt,p-mTOR,p62 and collagen Ⅰ expression,and lower LC3 Ⅱ expression and autophagosomes (all P ＜ 0.01).Further,compared with those in HG group,cells hypertrophy and proliferation in HG+miRNA-21 inhibitor group were reduced,expressions of p-Akt,p-mTOR,p62 and collagen Ⅰ were down-regulated,while expressions of PTEN and LC3 Ⅱ and autophagosomes were up-regulated (all P ＜ 0.01).Conclusions MiRNA-21 inhibitor up-regulates PTEN expression,which inhibits the activation of Akt/mTOR signaling pathway,ameliorates cell hypertrophy,proliferation and enhances autophagy to reduce extracellular matrix accumulation.