Evidence that hepatitis B virus replication in mouse cells is limited by the lack of a host cell dependency factor

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• 作者：Florian A. Lempp¹ ; Pascal Mutz¹ ; ² ; Christoph Lipps³ ; Dagmar Wirth³ ; Ralf Bartenschlager¹ ; ² ; ⁴ ; Stephan Urban¹ ; ⁴ ; ^{Stephan.Urban@med.uni-heidelberg.de" class="auth_mail" title="E-mail the corresponding author}
• 关键词：HBV ; hepatitis B virus ; HDV ; hepatitis delta virus ; NTCP ; sodium taurocholate cotransporting polypeptide ; hNTCP ; human sodium taurocholate cotransporting polypeptide ; PEG ; polyethylene glycol ; HBeAg ; hepatitis B virus e antigen ; HBsAg ; hepatitis B virus surface antigen ; HBcAg ; hepatitis B virus core antigen ; cccDNA ; covalently closed circular DNA ; HCC ; hepatocellular carcinoma ; mNTCP ; mouse sodium taurocholate cotransporting polypeptide ; aa ; amino acid ; DMSO ; dimethyl sulfoxide ; MyrB ; Myrcludex
• 刊名：Journal of Hepatology
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：64
• 期：3
• 页码：556-564
• 全文大小：3455 K

文摘

Hepatitis B virus (HBV) is a major human pathogen restricted to hepatocytes. Expression of the specific receptor human sodium taurocholate cotransporting polypeptide (hNTCP) in mouse hepatocytes renders them susceptible to hepatitis delta virus (HDV), a satellite of HBV; however, HBV remains restricted at an early stage of replication. This study aims at clarifying whether this restriction is caused by the lack of a dependency factor or the activity of a restriction factor.

Methods

Six hNTCP-expressing mouse and human cell lines were generated and functionally characterized. By fusion with replication-supporting but non-infectable HepG2 cells, we analysed the ability of these heterokaryonic cells to fully support HBV replication by HBcAg expression and HBsAg/HBeAg secretion.

Results

While hNTCP expression in three mouse cell lines and the non-hepatic human HeLa cells conferred susceptibility to HDV, HBV replication was still restricted. Upon fusion of refractive cells to HepG2 cells, all heterokaryonic cells supported receptor-mediated infection with HBV. hNTCP was provided by the mouse cells and replication competence came from the HepG2 cell line. Transfection of a covalently closed circular DNA (cccDNA)-like molecule into non-susceptible cells promoted gene expression, indicating that the limiting step is upstream of cccDNA formation.

Conclusions

In addition to the expression of hNTCP, establishment of HBV infection in mouse and non-hepatocytic human cell lines requires supplementation with a dependency factor and is not limited by a restriction factor. This result opens new avenues for the development of a fully permissive immunocompetent HBV mouse model.