Effects Of HMGB1-Mediated Autophagy-Lysosome Pathway On Inflammation And Apoptosis In Retinal Pigment Epithelial Cells Induced By High Glucose

Objective: The purpose of this paper is to enhance our knowledge concerning the effects and the underlying mechanism of the high mobility group protein B1(HMGB1)mediated autophagy-lysosome pathway on inflammation and apoptosis in retinal pigment epithelial cells induced by high glucose.Methods: Human retinal pigment epithelial cells(ARPE-19)were divided into the normal group(NG)and the high glucose(HG)group.autophagy inhibitor 3-MA or HMGB1 transfected siRNA were added into the culture solution.A blank control group and a negative control group were set up,the autophagosome was examined by electron microscopy,the expression of autophagy related proteins was detected by immunofluorescence,the expression of autophagy related proteins and HMGB1 was detected by Western blotting,the apoptosis was detected by flow cytometry,the intracellular reactive oxygen species(ROS)weredetected by DCFH-DA test,the mitochondrial membrane potential was detected by JC-1 test,the expression of cytokines and VEGF was detected by ELISA.Results: Compared with the NG conditions,the ARPE-19 cells cultured under HG conditions showed significantly increased autophagy vesicles,autophagy related proteins expression,autophagy degradation substrate,lysosomal membrane permeability and HMGB1 expression.After treated with autophagy inhibitor 3-MA in the hyperglycemia group,compared with the control group,apoptosis of ARPE-19 cells were significantly increased,and the release of inflammatory cytokines IL-1?,IL-6,IL-8 and VEGF was significantly increased.After treated with HMGB1 siRNA,compared with control group,the HMGB1 siRNA group decreased the expression of HMGB1 protein in ARPE-19 cells,reduced the degradation of the substrate,decreased the lysosome membrane permeability(LMP)and increased the lysosomal enzyme activity,additionally,increased mitochondrial membrane potential(MMP),intracellular reactive oxygen content is reduced,the release of cytochrome C decreased significantly,apoptosis significantly suppressed,the release of inflammatory cytokines IL-1?,IL-6,IL-8 and VEGF decreased obviously.Conclusion: 1.HG activates autophagy,but increases LMP,lysosomal function was impaired,leading to function of autophagy-lysosomal degradation decreased.2.Inhibition of autophagy can lead to increase the apoptosis of cells induced by HG,and increase the release of inflammatory cytokines IL-1?,IL-6,IL-8,as well as VEGF further.3.HG leads to increase the expression of HMGB1.After down-regulated the HMGB1 expression,it may restore the degradation function of autophagy by rescuing the LMP,increase the MMP,reduce the release of cytochrome C,inhibit cell apoptosis,and reduce the release of inflammatory factors and VEGF.