Effect Of CGAS,a Key Protein In CGAS-STING Signaling Pathway,On Autophagy And Apoptosis Of Human Bronchial Epithelial Cells

Objective: The aim of this study was to investigate the effects of cyclic guanosine adenosine phosphate synthase（cGAS）on autophagy and apoptosis of human bronchial epithelial cells,to further understand the mechanism of autophagy and apoptosis,and to provide new ideas for the prevention and treatment of chronic obstructive pulmonary disease.Method:（1）Human bronchial epithelial BEAS-2B cells were treated with adenovirus,and the expression of cGAS protein was detected by Western Blot.（2）BEAS-2B cells were treated with adenovirus（Ad V）,si RNA（si-cGAS）silencing cGAS gene and adenovirus respectively.The expression of cGAS m RNA and IFN-beta m RNA was detected by q RT-PCR.the expression levels of cGAS,LC3-I,LC3-II,p62 and cleaved-caspase-3 were detected by Western Blot.BEAS-2B cells were treated with cigarette smoke extract（CSE）,adenovirus alone and in combination.After treated with si-cGAS,BEAS-2B cells were treated with cigarette smoke extract,adenovirus alone and in combination,The expression of IFN-beta in cell supernatant was detected by ELISA.The expression of LC3-II,p62,cleaved-caspase-3 protein was detected by Western Blot.Results:（1）The expression of cGAS protein in BEAS-2B cells treated with adenovirus was higher than that in the control group.（2）After adenovirus（Ad V）treatment of BEAS-2B cells,the expression of cGAS m RNA,IFN-beta m RNA and IFN-beta in cell supernatant was higher than that of control group;after treatment with si-cGAS,the expression of cGAS m RNA,IFN-beta m RNA and IFN-beta in cell supernatant of si-cGAS+Ad V group was weaker than that of control group.（3）After adenovirus（Ad V）treatment of BEAS-2B cells,the expression of cGAS,LC3-II and cleaved-caspase-3 protein was enhanced compared with the control group,and the expression of p62 protein was weaker than that of the control group.After cigarette smoke extract（CSE）,adenovirus alone and combined treatment of BEAS-2B cells,the expression of LC3-II and cleaved-caspase-3 protein in the CSE group was enhanced than that in the control group,and the expression of p62 protein was weakened.After si-cGAS treatment,the expression of cGAS,LC3-II,cleaved-caspase-3protein was weakened and the expression of p62 protein was enhanced in si-cGAS+Ad V group compared with the corresponding control group.The expression of LC3-II and cleaved-caspase-3 was enhanced in CSE+Ad V group compared with CSE group,and the expression of p62 protein was weakened.After treatment with si-cGAS,the expression of LC3-II,cleaved-caspase-3 protein in si-cGAS+CSE+Ad V group were lower than those in corresponding control group,and the expression of p62 protein was enhanced.Conclusions:（1）cGAS was expressed in BEAS-2B cells.（2）In BEAS-2B cells,cGAS mediated adenoviral DNA induced IFN-beta expression.（3）In BEAS-2B cells,cGAS mediates adenovirus DNA-induced autophagy and apoptosis,adenovirus and cigarette smoke extracts have a combined effect on autophagy and apoptosis.（4）cGAS may be involved in the regulation of autophagy and apoptosis of BEAS-2B cells through cGAS-STING signaling pathway,and may be involved in the occurrence and development of COPD.