Study On FOSL2 And Related Cytokines In Patients With Chronic Hepatitis B

BackgroundHepatitis B virus(HBV)infection is a global public health challenge,Globally,more than 250 million people are still chronically infected with HBV.China is one of the countries with high incidence of hepatitis B.It is estimated that China has more than 1/3 of the world’s HBV infections,which is the key to achieving the global goal of eliminating HBV by 2030.Therefore,in China with a relatively high HBV infection rate,HBV-related research is attracting more and more attention.Although the existing antiviral treatment regimen can significantly reduce the HBV load in serum and liver tissues,chronic hepatitis B is difficult to treat and difficult to stop the drug and easy to relapse after stopping the drug.One of the reasons was due to the presence of transcriptional covalently closed circular DNA(cccDNA)in the liver nucleus,which cannot be cleared.So we are committed to studying chronic hepatitis B from the perspective of genes and cytokines,with the goal of exploring the pathogenesis of CHB and finding new therapeutic targets.Research has confirmed that in the process of HBV infection,HBV itself is not directly cytopathic,but the autoimmune reactions and host responses to the hepatocytes infected by it damage the liver cells directly or mediate antibody-dependent cytotoxicity that causes liver damage.T helper(Th)17 are CD4+T cells that are independent of Thl and Th2.There is extensive evidence that Th17 and its secreted interleukin 17(IL-17)play a key role in the development of the disease.IL-17(IL-17A)can mobilize,recruit and activate neutrophils,leading to massive tissue inflammation and promoting the progression of autoimmune disease,such asrheumatoid arthritis and multiple sclerosis.Interleukin-23(IL-23),a member of the IL-12 cytokine family,is expressed principally by the macrophages and DCs.It is considered essential for Th17 proliferation and differentiation.IL-23 receptor(IL-23R),expressed by both T cells and NK cells,was specific receptors of IL-23 and played key roles in pathogenesis of immune inflammatory diseases through combining with it.Overwhelming evidence has pointed to a pro-inflammatory role of the IL-23/IL-23R signaling pathway in inflammatory bowel disease(IBD),psoriasis and other immune diseases.Fos-like antigen 2(FOSL2/Fra2)is a member of the transcription factor family of activator protein-1(AP-1),and FOSL2 is the core component of Th17 action program.Previous studies have shown that FOSL2 can affect the immune status of the body by regulating the biological behavior and function of T cells 14.There are also some studies indicating down-regulation of FOSL2 during the occurrence of inflammation.The current understanding of FOSL2 is not comprehensive,and its role in liver disease,especially hepatitis B,has not been studied yet.Based on the results of previous studies,we speculated that FOSL2 may be involved in the development of CHB.The purpose of this study was to preliminarily explore the role of FOSL2 in the development and progression of CHB by studying the expression level of FOSL2 and some cytokines,such as IL-17,IL-23 and IL-23R,in patients with CHB and the possible regulatory mechanism.ObjectiveStudies have confirmed that FOSL2 may influence disease progression by participating in Th17 differentiation and regulating downstream genes,but its specific role in patients with chronic hepatitis B is unclear.The purpose of this study was to investigate the role of FOSL2,IL-17,IL-23 and IL-23R mRNA expressions in the occurrence and development of CHB,and to lay a foundation for the search for new therapeutic targets.MethodsIn this study,150 subjects were selected,including 111 patients with chronic hepatitis B(CHB)and 39 healthy volunteers as controls.According to Guidelines for the prevention and treatment of chronic hepatitis B(2019 edition),the presence of positive hepatitis B surface antigen(HBsAg)of CHB patients enrolled was for over 6 months.Among them,a total of 11 patients were excluded for the following reasons:7 patients with hepatocellular carcinoma,2 patients with alcoholic liver disease,1 patient with hepatitis E virus infection,1 patient with autoimmune liver disease,and 100 CHB patients were eventually included.HCs came from 39 healthy volunteers.The serum immunological examination and liver function examination were negative,excluding liver diseases and tumors,and there were no other respiratory,cardio-cerebrovascular,urinary and other system diseases.Fasting peripheral venous blood of all subjects were collected,mononuclear cells in peripheral blood(PBMCs)were extracted,RNA was extracted from PBMCs,and RNA was reversely transcribed.Real-time quantitative polymerase chain reaction(RT-qPCR)was used to detect the relative expression levels of FOSL2,IL-17,IL-23 and IL-23R mRNA in PBMCs.Statistical methods:In this study,continuous variables are represented by median or quartile.Classification variables are represented by relative frequencies.Kolmogorov-smirnov test was used to verify whether the data is normally distributed.Chi-square test was used to compare classification variables and Mann-Whitney U test was used to compare quantitative variables.The Spearman’s rank correlation test was used for correlation analysis.P value<0.05 was considered statistically significant.Results1.The expression of FOSL2 mRNA in patients with CHB were significantly lower than those in the HCs(P<0.001),while the expression of IL-17(P=0.005),IL-23(P=0.007),and IL-23R(P=0.001)mRNA were significantly higher than those in the HCs.2.we analyzed the correlations between FOSL2 and IL-17,IL-23 and IL-23R mRNA in CHB patients.We found that although the low expression level of FOSL2 was not significantly correlated with IL-23(p=0.935,r=-0.008),it was significantly negatively correlated with IL-17(p<0.001,r=-0.349)and IL-23R(p<0.001,r=-0.366).3.FOSL2 mRNA level in PBMCs of patients was negatively correlated with ALT level(r=-0.326,p=0.001),AST level(r=-0.287,p=0.004)and HBV DNA load(r=-0.229,p=0.022).But the correlation between it and patient gender(r=0.143,p=0.155),age(r=0.086,p=0.396),HBsAg(r=0.179,p=0.080),HBeAg(r=-0.146,p=0.150;Fig.4F),GGT(r=-0.069,p=0.495),AKP(r=-0.088,p=0.388),TBIL(r=-0.029,p=0.777),ALB(r=0.028,p=0.783);BUN(r=-0.021,p=0.838),Cr(r=-0.082,p=0.432),PT(r=0.037,p=0.713)and PTA(r=-0.016,p=0.855)was not statistically significant.Conclusion1.In CHB patients,the expression levels of FOSL2 mRNA were down-regulated,and the expression levels of IL-17,IL-23 and IL-23R mRNA were increased,and the down-regulated expression of FOSL2 was negatively correlated with IL-17 and IL-23R.This suggests that the downregulation of FOSL2 expression may induce overactivation of the inflammatory cytokine IL-23 signaling pathway by upregulating the expression of IL-17 and IL-23R.2.FOSL2 mRNA level was negatively correlated with ALT,AST and HBV DNA load.These indicators reflect the current situation of CHB infection and the severity of the disease,which may suggest that FOSL2 expression downregulation is involved in the development of CHB,and provide us with ideas for further research on the pathogenesis of CHB and the search for new therapeutic targets.