Long noncoding RNA protein-disulfide isomerase-associated 3 regulated high glucose-induced podocyte apoptosis in diabetic nephropathy through targeting miR-139-3p

BACKGROUND Podocyte apoptosis plays a vital role in proteinuria pathogenesis in diabetic nephropathy(DN).The regulatory relationship between long noncoding RNAs(lncRNAs)and podocyte apoptosis has recently become another research hot spot in the DN field.AIM To investigate whether lncRNA protein-disulfide isomerase-associated 3(Pdia3)could regulate podocyte apoptosis through miR-139-3p and revealed the underlying mechanism.METHODS Using normal glucose or high glucose(HG)-cultured podocytes,the cellular functions and exact mechanisms underlying the regulatory effects of lncRNA Pdia3 on podocyte apoptosis and endoplasmic reticulum stress(ERS)were explored.LncRNA Pdia3 and miR-139-3p expression were measured through quantitative real-time polymerase chain reaction.Relative cell viability was detected through the cell counting kit-8 colorimetric assay.The podocyte apoptosis rate in each group was measured through flow cytometry.The interaction between lncRNA Pdia3 and miR-139-3p was examined through the dual luciferase reporter assay.Finally,western blotting was performed to detect the effect of lncRNA Pdia3 on podocyte apoptosis and ERS via miR-139-3p.RESULTS The expression of lncRNA Pdia3 was significantly downregulated in HG-cultured podocytes.Next,lncRNA Pdia3 was involved in HG-induced podocyte apoptosis.Furthermore,the dual luciferase reporter assay confirmed the direct interaction between lncRNA Pdia3 and miR-139-3p.LncRNA Pdia3 overexpression attenuated podocyte apoptosis and ERS through miR-139-3p in HG-cultured podocytes.CONCLUSION Taken together,this study demonstrated that lncRNA Pdia3 overexpression could attenuate HG-induced podocyte apoptosis and ERS by acting as a competing endogenous RNA of miR-139-3p,which might provide a potential therapeutic target for DN.

Emodin Ameliorates High Glucose-Induced Podocyte Apoptosis via Regulating AMPK/mTOR-Mediated Autophagy Signaling Pathway

Objective To investigate the effect of emodin on high glucose(HG)-induced podocyte apoptosis and whether the potential anti-apoptotic mechanism of emodin is related to induction of adenosine-monophosphate-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR)-mediated autophagy in podocytes(MPC5 cells)in vitro.Methods MPC5 cells were treated with different concentrations of HG(2.5,5,10,20,40,80 and 160 mmol/L),emodin(2,4,8µmol/L),or HG(40 mmol/L)and emodin(4µmol/L)with or without rapamycin(Rap,100 nmol/L)and compound C(10µmol/L).The viability and apoptosis of MPC5 cells were detected using cell counting kit-8(CCK-8)assay and flow cytometry analysis,respectively.The expression levels of cleaved caspase-3,autophagy marker light chain 3(LC3)Ⅰ/Ⅱ,and AMPK/mTOR signaling pathway-related proteins were determined by Western blot.The changes of morphology and RFP-LC3 fluorescence were observed under microscopy.Results HG at 20,40,80 and 160 mmol/L dose-dependently induced cell apoptosis in MPC5 cells,whereas emodin(4µmol/L)significantly ameliorated HG-induced cell apoptosis and caspase-3 cleavage(P<0.01).Emodin(4µmol/L)significantly increased LC3-Ⅱ protein expression levels and induced RFP-LC3-containing punctate structures in MPC5 cells(P<0.01).Furthermore,the protective effects of emodin were mimicked by rapamycin(100 nmol/L).Moreover,emodin increased the phosphorylation of AMPK and suppressed the phosphorylation of mTOR.The AMPK inhibitor compound C(10µmol/L)reversed emodin-induced autophagy activation.Conclusion Emodin ameliorated HG-induced apoptosis of MPC5 cells in vitro that involved induction of autophagy through the AMPK/mTOR signaling pathway,which might provide a potential therapeutic option for diabetic nephropathy.