Methylation Status Of The Stimulator Of Interferon Genes Promoter In Patients With Chronic Hepatitis B

Background and aimsPatients with chronic hepatitis B(CHB)show the persistent presence of hepatitis B virus(HBV)in their hepatocytes or sera,and it's diffcult for them to clear the virus thoroughly.The stimulator of interferon genes(STING)can inhibit the replication of HBV DNA.This study aimed to investigate the methylation status of the STING promoter and assess STING mRNA expressionin in peripheral blood mononuclear cells(PBMCs)of patients with CHB and healthy controls(HCs).Furthermore,the study was also performed to examine whether the methylation status of the STING promoter affected the regulation of STING mRNA expression and response to antiviral therapy,and whether it can be used to develop potential new prevention and treatment strategies for patients with CHB.MethodsThis study included 198 participants,of which 159 participants had CHB and 39 were HCs.Methylation-specific polymerase chain reaction(MSP)was performed to detect the methylation status of the STING promoter.Reverse transcription-quantitative polymerase chain reaction(RT-qPCR)was performed to determine STING mRNA level in PBMCs.In addition,we screened 63 patients with CHB for follow-ups,to explore the effect of antiviral treatments.All the data were analyzed using SPSS 21 software.Quantitative variables are expressed as median(centile 25;centile 75),and categorical variables are expressed as number(%).The baseline characteristics of the participants were assessed using Mann-Whitney U test and chi-square test.The relationship between the methylation status of the STING promoter and the clinical features of the patients with CHB was investigated using multivariate logistic regression analysis.Unvariate and multivariate logistic regression analyses were used to investigate the relationship of the virological response of the patients with CHB with clinical features,STING promoter methylation status,and drug treatment.Spearman correlation was used to analyze the association between the quantitative and categorical variables.Results1.The methylation frequency of the STING promoter was significantly higher in the patients with CHB((69.81%)than in the HCs(23.08%)(P<0.001).2.STING promoter methylation was significantly correlated with HBV DNA(P=0.035),alanine aminotransferase(ALT)(P=0.040),aspartate aminotransferase(AST)(P=0.043),?-glutamyl transferase(GGT)(P=0.035),and akaline phosphatase(AKP)(P=0.030)levels.HBV DNA positivity was higher in the patients with CHB having methylated STING promoters than in those having unmethylated STING promoters(P=0.035).Results of multivariate logistic regression analysis indicated that only HBV DNA was independently correlated with an increased risk of STING promoter methylation(P=0.035).3.The STING mRNA level was evidently lower in the patients with CHB than in the HCs(P<0.001).Meanwhile,STING mRNA level was significantly lower in both the patients with CHB(P=0.023)and HCs(P<0.001)having methylated STING promoters than in those having unmethylated STING promoters.Moreover,STING mRNA level was lower in the patients showing HBV DNA positivity than in those showing HBV DNA negativity(P=0.046).4.The STING mRNA level was negatively correlated with ALT level(r=-0.218,P=0.006)and HBV DNA(r=-0.159,P=0.046),and was positively correlated with BUN(r=0.214,P=0.017)and Cr level(r=0,191,P=0.033).5.The virological response frequency was higher in the entecavir-treated patients than in the adefovir-treated patients(P=0.023).Moreover,the virological response frequency was lower in the entecavir-treated patients with methylated STING promoters than in those with unmethylated STING promoters(P=0.046).The multivariate logistic regression analysis showed that only STING promoter methylation status(P=0.027)was associated with the virological response.Conslusions1.In the present study,we found that the methylation frequency of the STING promoter was higher but the mRNA level was lower in the patients with CHB than in the HCs.The results indicate that the hypermethylation of the STING promoter reduced STING mRNA expression by decreasing gene transcription in patients with CHB.2.HBV DNA positivity was evidently higher in the patients with CHB having methylated STING promoters than in those having unmethylated STING promoters.Therefore,we concluded that STING methylation suppressed the effect of STING in inhibiting HBV replication.3.Among the entecavir-treated patients,the virological response frequency was lower in the patients having methylated STING promoters than in those having unmethylated STING promoters.It suggests that the STING methylation is related to antiviral therapies in patients with CHB,and the hypermethylation of the STING promoter can be used to develop potential new prevention and treatment strategies for patients with CHB,especially for patients who are sensitive to entecavir therapy.