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In a GWAS, we identified the association between the SNP rs17047200, within the intron of TLL1, and development of HCC in patients who achieved an SVR to treatment for chronic HCV infection. We found levels of Tll1/TLL1 mRNA to be increased in rodent models of liver injury and liver tissues of patients with fibrosis, compared with controls. We propose that this SNP might affect splicing of TLL1 mRNA, yielding short variants with high catalytic activity that accelerates hepatic fibrogenesis and carcinogenesis. Further studies are needed to determine how rs17047200 affects TLL1 mRNA levels, splicing, and translation, as well as the prevalence of this variant among other patients with HCC. Tests for the TLL1 SNP might be used to identify patients at risk for HCC after an SVR to treatment of HCV infection.

It has been reported that hepatitis C virus (HCV) may infect and replicate in human T cells, particularly in perihepatic lymph nodes, but the extent and consequence of T-cell infection in patients is unclear. This study is conducted to characterize the parameters and functional consequences of HCV infection in T lymphocytes. By using a lymphotropic HCV strain, we showed that HCV could infect T cell lines (Molt-4 and Jurkat cells) in vitro. Both positive- and negative-strand HCV RNA were detected for several weeks after infection. Viral proteins could also be detected by immunofluorescence studies. Moreover, infectious HCV particles were produced from Molt-4 cell cultures, and could be used to infect naïve T cell lines. HCV could also infect human primary CD4+ T cells, particularly naïve (CD45RA+CD45RO-) CD4+ cells, in culture. The amounts of STAT-1 and phosphorylated STAT-1 proteins in the infected Molt-4 cells were significantly less than those in uninfected cultures, suggesting the possibility of defect in interferon-gamma signaling. Indeed, T-bet and STAT-1 mRNA levels after interferon-gamma stimulation in infected Molt-4 were suppressed. In conclusion, HCV could infect and transiently replicate in T cells and that HCV replication suppressed the IFN-gamma/STAT-1/T-bet signaling due to the reduction of STAT-1 and inhibition of its activation (phosphorylation).

The molecular mechanisms of assembly and budding of hepatitis C virus (HCV) remain poorly understood. The budding of several enveloped viruses requires an endosomal sorting complex required for transport (ESCRT), which is part of the cellular machinery used to form multivesicular bodies (MVBs). Here, we demonstrated that Hrs, an ESCRT-0 component, is critical for the budding of HCV through the exosomal secretion pathway. Hrs depletion caused reduced exosome production, which paralleled with the decrease of HCV replication in the host cell, and that in the culture supernatant. Sucrose-density gradient separation of the culture supernatant of HCV-infected cells revealed the co-existence of HCV core proteins and the exosome marker. Furthermore, both the core protein and an envelope protein of HCV were detected in the intraluminal vesicles of MVBs. These results suggested that HCV secretion from host cells requires Hrs-dependent exosomal pathway in which the viral assembly is also involved.

Various findings concerning the clinical significance of quantitative changes in hepatitis B surface antigen (HBsAg) during the acute and chronic phase of hepatitis B virus (HBV) infection have been reported. In addition to being a biomarker of HBV-replication activity, it has been reported that HBsAg could contribute to the immunopathogenesis of HBV persistent infection. Moreover, HBsAg could become an attractive target for immune therapy, since the cellular and humeral immune response against HBsAg might be able to control the HBV replication and life cycle. However, several reports have described the immune suppressive function of HBsAg. HBsAg might suppress monocytes, dendritic cells (DCs), natural killer (NK), and natural killer T (NK-T) cells by direct interaction. On the other hand, cytotoxic T lymphocytes (CTLs) and helper T (Th) cells were exhausted by high amounts of HBsAg. In this paper, we focused on the immunological aspects of HBsAg, since better understanding of the interaction between HBsAg and immune cells could contribute to the development of an immune therapy as well as a biomarker of the state of HBV persistent infection.

Background and Aims: Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. Nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD, and advanced fibrosis are associated with poor outcomes. We searched for their noninvasive biomarkers.Approach and Results: Global RNA sequencing of liver tissue from 98 patients with biopsy-proven NAFLD was performed. Unsupervised hierarchical clustering well distinguished NASH from nonalcoholic fatty liver (NAFL), and NASH patients exhibited molecular abnormalities reflecting their pathological features. Transcriptomic analysis identified proteins upregulated in NASH and/or advanced fibrosis (stage F3-4), including matricellular glycoprotein thrombospondin-2 (TSP-2), encoded by the thrombospondin 2 (THBS2) gene. The intrahepatic THBS2 expression level showed the highest areas under the receiver operating characteristic curves (AUROCs) of 0.915 and 0.957 for diagnosing NASH and advanced fibrosis, respectively. THBS2 positively correlated with inflammation and ballooning according to NAFLD activity score, serum aspartate aminotransferase and hyaluronic acid (HA) levels, and NAFLD Fibrosis Score (NFS). THBS2 was associated with extracellular matrix and collagen biosynthesis, platelet activation, caspase-mediated cleavage of cytoskeletal proteins, and immune cell infiltration. Serum TSP-2 expression was measured in 213 patients with biopsy-proven NAFLD, was significantly higher in NASH than in NAFL, and increased parallel to fibrosis stage. The AUROCs for predicting NASH and advanced fibrosis were 0.776 and 0.856, respectively, which were comparable to Fibrosis-4 index, serum HA level, and NFS in advanced fibrosis diagnosis. Serum TSP-2 level and platelet count were independent predictors of NASH and advanced Accepted ArticleThis article is protected by copyright. All rights reserved fibrosis. Serum TSP-2 levels could stratify NAFLD patients according to the risk of hepatic complications, including liver cancer and decompensated cirrhotic events.Conclusions: TSP-2 may be a useful biomarker for NASH and advanced fibrosis diagnosis in NAFLD patients.

Accumulating evidence suggests that cancer stem cells (CSC) play an important role in tumorigenicity. Epithelial cell adhesion molecule (EpCAM) is one of the markers that identifies tumor cells with high tumorigenicity. The expression of EpCAM in liver progenitor cells prompted us to investigate whether CSC could be identified in hepatocellular carcinoma (HCC) cell lines. The sorted EpCAM+ subpopulation from HCC cell lines showed a greater colony formation rate than the sorted EpCAM− subpopulation from the same cell lines, although cell proliferation was comparable between the two subpopulations. The in vivo evaluation of tumorigenicity, using supra‐immunodeficient NOD/scid/γcnull (NOG) mice, revealed that a smaller number of EpCAM+ cells (minimum 100) than EpCAM− cells was necessary for tumor formation. The bifurcated differentiation of EpCAM+ cell clones into both EpCAM+ and EpCAM− cells was obvious both in vitro and in vivo, but EpCAM− clones sustained their phenotype. These clonal analyses suggested that EpCAM+ cells may contain a multipotent cell population. Interestingly, the introduction of exogenous EpCAM into EpCAM+ clones, but not into EpCAM− clones, markedly enhanced their tumor‐forming ability, even though both transfectants expressed a similar level of EpCAM. Therefore, the difference in the tumor‐forming ability between EpCAM+ and EpCAM− cells is probably due to the intrinsic biological differences between them. Collectively, our results suggest that the EpCAM+ population is biologically quite different from the EpCAM− population in HCC cell lines, and preferentially contains a highly tumorigenic cell population with the characteristics of CSC. (Cancer Sci 2010)

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