HoxA10 Represses Hepatitis B Virus Replication Through Recruiting SHP-1 To Attenuate The P38 Pathway And Down-Regulating Dephosphorylation Of STAT3

Hepatitis B virus(HBV)infection is still one of the most serious viral infections.More than 350 million people worldwide are chronically infected with HBV.Many of them develop liver cirrhosis and hepatocellular carcinoma(HCC).Hepatocellular carcinoma is the sixth most common cancer in the world and the third leading cause of cancer-related deaths worldwide,causing approximately 800,000 deaths each year.More than 85% of Hepatocellular carcinoma are caused by HBV or HCV infection,of which HBV is the main part.Three major modes of transmission prevail.In areas of high chronic HBV prevalence,HBV is transmitted mostly perinatally from infected mothers to neonates.In low chronic HBV prevalence areas,sexual transmission is predominant.The third major source of infection is blood transfusions.Roughly 75% of HBV-infected people are Asians and Africans and have a lower transmission rate in Western countries.But the overall incidence has still increased,especially in the United States and Western European countries.At present,although effective preventive vaccines already exist,vaccination is not well implemented and the vaccine is not 100% effective.Persistent Hepatitis B virus(HBV)infection remains a serious threat to global public health problem.The outcome of acute HBV infection is age dependent.Roughly 95% of neonates,20–30% of children(aged 1–5 years)and less than 5% of adults develop chronic infection.Once infected,HBV will establish the basis of persistent chronic infection to facilitate long-term carrying in the host and increase the threat of liver disease.We need a deep understanding of how HBV builds persistent infections and the mechanisms that cause cirrhosis and Hepatocellular carcinoma.Development of new effective therapies and drugs to control the progression of HBV.The human homeobox gene(Hox)belongs to the transcriptional regulatory gene of a multi-gene family.The homeobox protein is a highly conserved transcription factor that activates or inhibits the target gene by binding to DNA.In mammal,the genes encoding the class of transcription factors called homeobox genes are grouped into four clusters named A,B,C,and D,which are located on 7,17,12,2 chromosomes,respectively.Homeobox protein A10(HoxA10)is belongs to a large family of Homeobox protein,a DNA-binding transcription factor share sequence specific DNA binding activity,which may regulate gene expression,morphogenesis,and differentiation.More specifically,it may function in fertility,embryo viability,and regulation of hematopoietic lineage commitment.At present,a large number of studies have shown that HoxA10 plays an important role in embryonic development,differentiation,cancer,and hematopoietic diseases.However,the role of HoxA10 in viral infection and replication has not been reported.We are collected and tested the mRNA levels of HoxA10 in the blood leukocytes of patients with chronic hepatitis B and healthy dividuals,and found that the HoxA10 expression level of patients was significantly higher than that of healthy individuals.HBV infection also activates the expression level of HoxA10 in isolated healthy human peripheral blood mononuclear cells(PBMCs)and cells cultured in vitro.In overexpression and interference experiments,it was confirmed that HoxA10 can inhibit HBV replication.First,the HBV-infected cultured hepatic cells,HepG2-NTCP cells activated the expression of p38 MAPK and HoxA10,HBV stimulated the expression of HoxA10 in PBMCs and the expression level of leukocyte HoxA10 in patients with chronic hepatitis B was higher than that in healthy individuals.Further investigations revealed that HBV-infected hepatocytes(HepG2 and Huh7)and HepG2-NTCP cell lines can activate phosphorylation of p38 MAPK,thereby activation of downstream STAT3 phosphorylation,and phosphoryl-STAT3 bind HBV Ehn I/X promoter to promote HBV replication.However,HoxA10 can promote dephosphorylation of phosphorylated p38 MAPK by recruitment of phosphatase SHP-1 to inhibit activation of downstream STAT3,which can inhibit HBV replication.Using inhibitor of p38 MAPK pathway,we confirmed that HoxA10 attenuates HBV replication through repressing p38 MAPK/STAT3 pathway.In CHIP and the dual fluorescent reporter plasmid exprements,we found that HoxA10 can directly bind to the X promoter to inhibit its activity.Finally,it was confirmed that HoxA10 may exert its inhibition by the mechanism of competitive adsorption HBV EnhI/X promoter with STAT3.Here,we first found that HBV infection activates HoxA10 expression and confirms that HBV infection activates HoxA10 and p38 MAPK signaling pathways,and that HoxA10 inhibits HBV replication by negatively regulating the p38MAPK/STAT3 pathway.First,HBV infected cultured hepatic cells,HepG2-NTCP cells activated the expression of p38 MAPK and HoxA10,HBV stimulated the expression of HoxA10 in PBMCs and the expression level of leukocyte HoxA10 in patients with chronic hepatitis B was higher than that in healthyindividuals.Secondly,HoxA10 negatively regulates p38 MAPK signaling pathway by phosphatase SHP-1,which inhibits the activation of STAT3 downstream of the p38 MAPK pathway,thereby inhibiting the binding of activated STAT3 to HBV enhancer I,and finally inhibiting HBV transcription.On the other hand,HoxA10 is also can directly binding to the X promoter of HBV to inhibit the transcription activity of the X promoter,inhibit the replication of HBV.In addition,we also found that HoxA10 may compete with STAT3 for competitive binding to the X promoter.In conclusion,we reveal a negative feedback regulatory mechanism underlying the regulations of HBV replication and HoxA10 production.One hand,HBV activate HoxA10 expression;On the other hand,HoxA10 inhibits HBV replication through inhibiting the p38MAPK/STAT3 signaling pathway.In addition,HoxA10 can also directly bind HBV X promoter to inhibit HBV replication.