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.