Hepatitis B Virus Induces Autophagy To Promote Its Replication By The Axis Of MiR-192-3p-XIAP Through NF Kappa B Signaling

Chronic infection of Hepatitis B virus(HBV)is a major risk factor for the development and progression of Hepatocellular carcinoma(HCC).Although the popularity of HBV vaccines has significantly reduced the number of new infections,and the treatment of antiviral drugs,such as nucleoside analogues and interferon,has also dramatically decreased the mortality of infected patients.However,because cccDNA produced in the process of HBV infection can not be completely cleared by currently available drugs,there are still more than three hundred fifty million people worldwide are infected with HBV,and approximately eight hundred eighty-seven thousand people each year die from HBV-related liver cirrhosis,liver cancer and other complications.In order to provide a theoretical basis for exploring new therapeutic targets and developing new therapeutic drugs to prevent and treat hepatitis B and liver cancer,further study is require to clarify the mechanism of persistent replication and pathogenesis of HBV.Emerging evidence indicates that miRNAs are involved in HBV replication and HBV-related hepatocarcinogenesis.miRNAs are a class of short,endogenous,non-coding RNAs,which can regulate gene expression post-transcriptionally through binding to complementary sequences in the 3'-untranslated regions(3'-UTR)of the target transcripts.It also has been well documented that HBV can up-regulate or down-regulate the expression of a variety of intracellular miRNAs,and cellular miRNAs have been demonstrated to play an important role in HBV infection,for example,miRNA can eliminate viral infection in host cells by affecting processes such as those important for viral replication.Autophagy is a catabolic process used by eukaryotic cells to degrade and recycle unfold or misfolded proteins,damaged organelles and invading pathogens to maintain intracellular homeostasis.It has been shown that HBV infection can cause autophagy in the host cells and that X and S proteins are crucial regulation factors participated in mechanisms of HBV-induced autophagy.Moreover,the autophagic pathway is important for HBV amplification in host cells.Many autophagy-related genes such as Atg5,Beclin-1 and LC3 have been shown to be target genes for miRNAs and can be regulated by miRNAs.Based on Recent publications,the functional study of autophagy mediated by miRNA have become a rising concern in the field of virology research.However,how miRNAs become the link between HBV-induced autophagy and the enhancement of HBV replication remains largely unknown.At first,we selected 11 differentially expressed miRNA,such as miR-340-5p and miR-192-3p et al,from the reported miRNA expression profiles of normal and HBV patients,We verified the results of expression profile.Basing on the previous research and our experimental results,our study focus on miR-192-3p.In this study,we found that decreasing levels of the expression of the miR-192-3p is associated with rising levels of HBV DNA in the serum of HBV patients.Subsequently,molecular mechanism studies showed that HBV infection repressed the expression of miR-192-3p through hepatitis B x protein interaction with c-myc.In order to explore the function of HBV inhibiting miR-192-3p,we screened and identified XIAP as a new target gene of miR-192-3p.At the same time,we revealed that miR-192-3p,as an autophagy inhibitor,was repressed by HBV transfection in vitro and in a mouse model,leading to cellular autophagy.Importantly,we discovered that HBV promoted autophagy through miR-192-3p-XIAP axis and that this process was important for HBV replication in vitro and in vivo.We further demonstrated that miR-192-3p functioned through the nuclear factor kappa B signaling pathway to inhibit autophagy,thereby reducing HBV replication.Finally,we confirmed that HBV activates NF-?B signaling pathway through miR-192-3p targeting XIAP to upregulate the expression of Beclin-1,thus promoting autophagy and increasing HBV replication.In conclusion,our study found that HBV induced autophagy through miR-192-3p-XIAP-NF-?B axis to promotes HBV replication,which is a positive feedback loop pathway.The key point of the pathway may become a new target for the development of drugs for HBV-related diseases in the future.In addition,our findings indicate that miR-192-3p is a regulator of HBV infection and may play a potential role in hepatocellular carcinoma.It may also serve as a biomarker or therapeutic target for HBV patients.