The Role And Mechanism Of Down-regulation Of SIRT1 By IRF9 In Acute Pancreatitis

Objective: To explore the role of negative regulation of histone deacetylase SIRT1 by interferon regulatory factor IRF9 in the development of acute pancreatitis(AP),and provide theoretical guidance for disease diagnosis and treatment.Methods: The AR42 J cells at logarithmic growth stage were divided into blank control group,negative control group and IRF9 silencing group.After successful transfection of si RNA,the model of acute pancreatitis in vitro was constructed by cerulean treated.The values of amylase,IL-1? and TNF-? were measured by ELISA after 24 hours treated with cerulean.The m RNA and protein expression levels of IRF9 and SIRT1 in AR42 J cells were determined by q RT-PCR and western blot.The expression levels of p53 and acetylated p53 were detected by western blot.The apoptosis rate of AR42 J cells in each group was checked by Annexin V-FITC/PI double staining assay.Cell migration and proliferation were detected by Transwell and MTT.Double luciferase reporter experiment validates the targeted regulation of SIRT1 by IRF9 in AP.Results:(1)The levels of amylase,IL-1? and TNF-? were increased after 24 hours treated with cerulean,indicating that the cell model of acute pancreatitis was successfully constructed in vitro.(2)Comparing with the blank control group and the negative control group,the m RNA and protein levels of IRF9 gene in IRF9 silencing group decreased,the differences were statistically significant(P<0.05).The m RNA and protein levels of IRF9 gene in the negative control group showed no significant difference.These results indicated that the silencing of IRF9 gene was successful.(3)The m RNA and protein levels of IRF9 gene in each group increased after 24 hours treated with cerulean.The m RNA and protein levels of SIRT1 gene in each group decreased after 24 hours treated with cerulean.The expression of p53 and acetylated p53 significantly increased.These results suggested that the expression levels of IRF9,p53 and acetylated p53 were up-regulated and the expression level of SIRT1was down-regulated when acute pancreatitis occurred.(4)Comparing with the blank control group and the negative control group,the m RNA and protein levels of SIRT1 gene in IRF9 silencing group increased,the differences were statistically significant(P<0.05).(5)Comparing with the blank control group,the apoptosis rate of AR42 J cells in IRF9 silencing group was significantly reduced after cerulean treated(P<0.05).(6)Comparing with the blank control group,the migration of AR42 J cells in IRF9 silencing group was significantly reduced after cerulean treated(P<0.05).(7)Comparing with the blank control group,the proliferation of AR42 J cells in IRF9 silencing group was significantly reduced after cerulean treated(P<0.05).(8)Double luciferase gene experiment results showed that the activity of SIRT1 promoter was repressed when IRF9 was overexpressed.Conclusion: IRF9 acted as a negative regulator of SIRT1 to down-regulate the expression of SIRT1,promoted the acetylation of p53,increased the apoptosis rate,enhanced the cell migration and proliferation when acute pancreatitis occurred.When IRF9 gene was silenced,the expression of SIRT1 increased.The acetylation level of p53,the apoptosis rate,the cell migration and proliferation decreased.The potential mechanism was that IRF9 bind the promoter of SIRT1 to repress its expression,thus to increase Ac-p53,elevate cell apoptosis,proliferation and migration.These results might provide theoretical guidance and experiment basis for the study of the pathogenesis and treatment of AP.