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Association of genetic variation of sodium taurocholate cotransporting polypeptide with chronic hepatitis B virus infection.

ABSTRACT: Sodium taurocholate cotransporting polypeptide (NTCP) plays an important role in the enterohepatic circulation of bile acids and hepatocyte function and was recently proposed to be a functional receptor for hepatitis B virus (HBV).This study investigated the association of the functional polymorphism c.800C>T (p.S267F) (rs2296651) of the NTCP gene with HBV infection.The study included 244 patients with chronic HBV infection, 76 HBV infection resolvers, and 113 healthy controls. The polymorphism was genotyped using the polymerase chain reaction-restriction fragment length polymorphism method.The distribution of the genotype and allele frequency of rs2296651 polymorphism was significantly different among the HBV patients, HBV infection resolvers, and healthy controls (p=0.034 and p=0.039, respectively). The frequency of genotype CT in HBV patients was significantly higher than that in healthy controls (11.9% vs. 4.4%, p=0.026, odds ratios [OR]=2.913, 95% confidence intervals [95% CI]=1.097-7.738). The frequency of allele T in HBV patients was also significantly higher than that in healthy controls (5.9% vs. 2.2%, p=0.029, OR=2.793, 95% CI=1.067-7.312). The frequency of genotype CT and allele T in HBV patients was higher than that in HBV infection resolvers although the difference was not significant. The genotype and allele frequency between infection resolvers and healthy controls and between HBV patients with different clinical diseases had no significant difference.These findings suggest that the rs2296651 polymorphism may predispose the susceptibility to and chronicity of HBV infection.

SUBMITTER: Li N

PROVIDER: S-EPMC4043369 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature

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Association of genetic variation of sodium taurocholate cotransporting polypeptide with chronic hepatitis B virus infection.

Li Na N Zhang Pingping P Yang Cuiling C Zhu Qianqian Q Li Zhu Z Li Fang F Han Qunying Q Wang Yawen Y Lv Yi Y Wei Ping P Liu Zhengwen Z

Genetic testing and molecular biomarkers 20140415 6

<h4>Background</h4>Sodium taurocholate cotransporting polypeptide (NTCP) plays an important role in the enterohepatic circulation of bile acids and hepatocyte function and was recently proposed to be a functional receptor for hepatitis B virus (HBV).<h4>Objective</h4>This study investigated the association of the functional polymorphism c.800C>T (p.S267F) (rs2296651) of the NTCP gene with HBV infection.<h4>Methods</h4>The study included 244 patients with chronic HBV infection, 76 HBV infection r ...[more]

PMID: 24735529

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Project description:Cell culture (cc)-derived hepatitis B virus (HBV) can infect differentiated HepaRG cells, but efficient infection requires addition of polyethylene glycol (PEG) during inoculation. Identification of sodium taurocholate cotransporting polypeptide (NTCP) as an HBV receptor enabled ccHBV infection of NTCP reconstituted HepG2 cells, although very little hepatitis B surface antigen (HBsAg) is produced. We found infection by patient serum-derived HBV (sHBV), which required purification of viral particles through ultracentrifugation or PEG precipitation, was PEG independent and much more efficient in HepaRG cells than in HepG2/NTCP cells. In contrast to hepatitis B e antigen (HBeAg), HBsAg was not a reliable marker of productive sHBV infection at early time points. A low HBsAg/HBeAg ratio by ccHBV-infected HepG2/NTCP cells was attributable to dimethyl sulfoxide (DMSO) in culture medium, NTCP overexpression, and HBV genotype D. HepG2/NTCP cells released more viral antigens than HepG2 cells after HBV genome delivery by adeno-associated virus, and stable expression of NTCP in a ccHBV producing cell line increased viral mRNAs, proteins, replicative DNA, and covalently closed circular DNA. NTCP protein expression in HepG2/NTCP cells, despite being driven by the cytomegalovirus promoter, was markedly increased by DMSO treatment. This at least partly explains ability of DMSO to promote ccHBV infection in such cell lines. In conclusion, NTCP appeared inefficient to mediate infection by serum-derived HBV. It could promote HBV RNA transcription while inhibiting HBsAg secretion. Efficient PEG-independent sHBV infection of HepaRG cells permits comparative studies of diverse clinical HBV isolates and will help identify additional factors on virion surface promoting attachment to hepatocytes.Currently in vitro infection with hepatitis B virus (HBV) depends on cell culture-derived HBV inoculated in the presence of polyethylene glycol. We found patient serum-derived HBV could efficiently infect differentiated HepaRG cells independent of polyethylene glycol, which represents a more physiological infection system. Serum-derived HBV has poor infectivity in HepG2 cells reconstituted with sodium taurocholate cotransporting polypeptide (NTCP), the currently accepted HBV receptor. Moreover, HepG2/NTCP cells secreted very little hepatitis B surface antigen after infection with cell culture-derived HBV, which was attributed to NTCP overexpression, genotype D virus, and dimethyl sulfoxide added to culture medium. NTCP could promote HBV RNA transcription, protein expression, and DNA replication in HepG2 cells stably transfected with HBV DNA, while dimethyl sulfoxide could increase NTCP protein level despite transcriptional control by a cytomegalovirus promoter. Therefore, this study revealed several unusual features of NTCP as an HBV receptor and established conditions for efficient serum virus infection in vitro.

Project description:Sodium taurocholate cotransporting polypeptide (NTCP) has been identified as a hepatitis B virus (HBV) receptor, and its overexpression in HepG2 cell lines leads to efficient secretion of hepatitis B e antigen (HBeAg) following challenge with a large dose of cell culture-derived HBV (cHBV) particles. However, NTCP-reconstituted HepG2 cells are inefficiently infected by patient serum-derived HBV (sHBV) and release very little hepatitis B surface antigen (HBsAg) following cHBV infection, unlike differentiated HepaRG cells, which are naturally susceptible to both cHBV and sHBV particles. Here, we investigated whether NTCP could explain the different behaviors of the two cell types. Endogenous NTCP protein from differentiated HepaRG cells was unglycosylated despite wild-type coding sequence. HepaRG cells stably transfected with an epitope-tagged NTCP expression construct displayed higher sHBV but not cHBV susceptibility than cells transfected with the null mutant. Tagged NTCP introduced to both HepG2 and HepaRG cells was glycosylated, with N5 and N11 being sites of N-linked glycosylation. Mutating N5, N11, or both did not alter cell surface availability of NTCP or its subcellular localization, with both the singly glycosylated and nonglycosylated forms still capable of mediating cHBV infection in HepG2 cells. In conclusion, nonglycosylated NTCP is expressed by differentiated HepaRG cells and capable of mediating cHBV infection in HepG2 cells, but it cannot explain differential susceptibility of HepaRG and HepG2/NTCP cells to cHBV versus sHBV infection and different HBsAg/HBeAg ratios following cHBV infection. The responsible host factor(s) remains to be identified.IMPORTANCE HBV can infect differentiated HepaRG cells and also HepG2 cells overexpressing NTCP, the currently accepted HBV receptor. However, HepG2/NTCP cells remain poorly susceptible to patient serum-derived HBV particles and release very little hepatitis B surface antigen following infection by cell culture-derived HBV. We found differentiated HepaRG cells expressed nonglycosylated NTCP despite a wild-type coding sequence. NTCP introduced to HepG2 cells was glycosylated at two N-linked glycosylation sites, but mutating either or both sites failed to prevent infection by cell culture-derived HBV or to confer susceptibility to serum-derived HBV. Overexpressing NTCP in HepRG cells did not increase infection by cell culture-derived HBV or distort the ratio between the two viral antigens. These findings suggest that host factors unique to HepaRG cells are required for efficient infection by serum-derived HBV, and factors other than NTCP contribute to balanced viral antigen production following infection by cell culture-derived HBV.

Dataset Information

Association of genetic variation of sodium taurocholate cotransporting polypeptide with chronic hepatitis B virus infection.

Publications

Association of genetic variation of sodium taurocholate cotransporting polypeptide with chronic hepatitis B virus infection.

Similar Datasets

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