7,8-DHF Protects Human Renal Proximal Tubular Cells From Hypoxia Injury Via Inhibiting ERS

Objective To observe the effects of 7,8-Dihydroxyflavone(7,8-DHF)on hypoxia induced endoplasmic reticulum stress(ERS)in human proximal tubular epithelial cells(HK-2).Methods The mRNA level of ERS associated biomarkers were evaluated by RT-PCR assay in cell hypoxia damaged model.And HK-2 cells were pretreated with different concentrations of 7,8-DHF through CCK-8 assay;and CCAAT/enhancer-binding protein homologous protein(CHOP),Cyr61,Akt and p-Akt were determined by western blotting assay.Moreover,HK-2 cells were pretreated by a kind of PI3K/Akt inhibitor,LY294002 to inhibit the PI3K/Akt signaling,and detect the effects on protein level induced by 7,8-DHF.Then HK-2 cells was over-expressed Cyr61 and exposed to hypoxia,and apoptosis rate and CHOP expression were determined.Results Hypoxia for 12 h was effective to induce ERS(P<0.01),while pretreatment with 7,8-DHF(100 ?mol/L)increased cell proliferation significantly vs hypoxia group(P<0.01).The protein expression of Cyr61 and p-Akt in H+7,8-DHF group was higher,but the level of CHOP was decreased(P<0.05).With LY294002 pretreated,the expression Cyr61,p-Akt was down-regulated(all P<0.05),the expression of CHOP was up-regulated(P<0.05).In comparison to empty plasmid group,when cells were transfected with over-expression of Cyr61 plasmid and exposed to hypoxia,the number of apoptotic tubular cells was decreased(P<0.01).And over-expression of Cyr61 significantly reduced CHOP expression compared with the empty plasmid group(P<0.01).Conclusions Pretreatment of 7,8-DHF could protect cells from hypoxia injury and inhibit ERS,which may involve the Akt-Cyr61 signaling pathway.