Study On The Mechanism Of Histone H3K4 Methylation In The Process Of Apoptosis Of Hepatocyte ERS Pathway Induced By Arsenic

Objective:To investigate the changes of H3K4 methylation level in human normal hepatocyte apoptosis induced by arsenic poisoning,and its mechanism of regulating endoplasmic reticulum stress PERK signaling pathway to promote apoptosis.Methods:The cells were treated with different concentrations of arsenic for 24 h,and the arsenic poisoning hepatocyte injury model was replicated by treating the LO2 cells with 100?mol/L sodium arsenite for 24 h.Human liver cell LO2 was divided into control group,model group,SET7/9(SET domain containing 7/9)siRNA group,SET7/9 siRNA negative transfection group(Negative siRNA),LSD1(lysine specific demethylase 1)overexpression group,LSD1 overexpression negative transfection group(Negative shRNA),LSD1 inhibitor group(OG-L002).Real-time cellular analysis(RTCA)was used to detect the effects of cell proliferation in each group;The cell cycle and apoptosis of each group were detected by flow cytometry;Western blot was used to observe the expression levels of GRP78,PERK,p-PERK,p-eIF2?(Ser51),CHOP,H3K4 me and SET7/9 in control group,model group,Negative siRNA transfection group and SET7/9 siRNA transfection group;The expression levels of GRP78,CHOP,H3K4 me,H3K4me2 and LSD1 in the control group,model group,Negative shRNA transfection group,LSD1 group and OG-L002 group were observed by Western blot;Results:RTCA results showed that the proliferation of the model group was significantly inhibited compared with the control group,the inhibition of cell proliferation in SET7/9 siRNA transfection group was significantly reduced compared with Negative siRNA transfection group,the inhibition of cell proliferation was significantly reduced in the LSD1 group compared with the Negative shRNA transfection group and the OG-L002 group.The results of flow cytometry showed that the apoptosis rate of the model group was significantly higher than that of the control group,the apoptosis rate of SET7/9 siRNA transfection group was significantly lower than that of Negative siRNA transfection group,the apoptosis rate of LSD1 group was significantly lower than that of Negative shRNA transfection group,the apoptosis rate of OG-L002 group was significantly higher than that of Negative shRNA transfection group.Western Blotting showed that the expression levels of GRP78,p-PERK,p-eIF2?(Ser51),CHOP and H3K4 me were significantly higher in the model group than in the control group,the SET7/9 siRNA transfection group was significantly lower than the Negative siRNA transfection group;The expression levels of GRP78,CHOP,H3K4 me and H3K4me2 were significantly lower in the LSD1 group than in the Negative shRNA transfection group,the OG-L002 group was significantly higher than the LSD1 group and the Negative shRNA transfection group.Conclusion:Arsenic exposure can induce apoptosis in LO2 cells;The process of apoptosis induced by arsenic exposure in LO2 cells is related to the PERK signaling pathway that activates endoplasmic reticulum stress;Changes in H3K4 methylation levels can modulate arsenic-induced hepatocyte apoptosis by regulating the PERK signaling pathway.