A20 in hepatic stellate cells suppresses chronic hepatitis by inhibiting DCLK1-JNK pathway-dependent chemokines.

Hepatic stellate cells (HSCs) are responsible for liver fibrosis accompanied by its activation into myofibroblasts and the abundant production of extracellular matrix. However, the HSC contribution to progression of liver inflammation has been less known. We aimed to elucidate the mechanism in HSCs underlying the inflammatory response and the function of tumor necrosis factor α-related protein A20 (TNFAIP3). We established A20 conditional knockout (KO) mice crossing Twist2-Cre and A20 floxed mice. Using these mice, the effect of A20 was analyzed in mouse liver and HSCs. The human HSC line LX-2 was also used to examine the role and underlying molecular mechanism of A20. In this KO model, A20 was deficient in >80% of HSCs. Spontaneous inflammation with mild fibrosis was found in the liver of the mouse model without any exogenous agents, suggesting that A20 in HSCs suppresses chronic hepatitis. Comprehensive RNA sequence analysis revealed that A20-deficient HSCs exhibited an inflammatory phenotype and abnormally expressed chemokines. A20 suppressed JNK pathway activation in HSCs. Loss of A20 function in LX-2 cells also induced excessive chemokine expression, mimicking A20-deficient HSCs. A20 overexpression suppressed chemokine expression in LX-2. In addition, we identified DCLK1 in the genes regulated by A20. DCLK1 activated the JNK pathway and upregulates chemokine expression. DCLK1 inhibition significantly decreased chemokine induction by A20-silencing, suggesting that A20 controlled chemokine expression in HSCs via the DCLK1-JNK pathway. In conclusion, A20 suppresses chemokine induction dependent on the DCLK1-JNK signaling pathway. These findings demonstrate the therapeutic potential of A20 and the DCLK1-JNK pathway for the regulation of inflammation in chronic hepatitis.

Analysis of prognosis and background liver disease in non-advanced hepatocellular carcinoma in two decades.

BACKGROUND/AIM: Antiviral hepatitis and systemic therapies for hepatocellular carcinoma (HCC) remarkably progressed in the recent 10 years. This study aimed to reveal the actual transition and changes in the prognosis and background liver disease in non-advanced HCC in the past 20 years. METHODS: This retrospectively recruited 566 patients who were diagnosed with non-advanced HCC from February 2002 to February 2022. The prognosis was analyzed by subdividing according to the diagnosis date (period I: February 2002-April 2009 and period Ⅱ: May 2009-February 2022). RESULTS: Patients in period II (n = 351) were significantly older, with lower albumin-bilirubin (ALBI) scores and alpha-fetoprotein (AFP) and more anti-viral therapy, systemic therapy, and hepatic arterial infusion chemotherapy as compared with those in period I (n = 215). The etiology ratio of the background liver disease revealed decreased hepatitis C virus from 70.6% to 49.0% and increased non-B, non-C from 17.7% to 39.9% from periods I to Ⅱ. The multivariate analysis revealed older age and higher ALBI score in Barcelona Clinic Liver Cancer (BCLC) 0/A stage, AFP of >20 ng/mL, and higher ALBI score in BCLC B stage as independent prognosis factors. Fine-Gray competing risk model analysis revealed that liver-related deaths significantly decreased in period II as compared to period I, especially for BCLC stage 0/A (HR: 0.656; 95%CI: 0.442-0.972, P = 0.036). CONCLUSION: The characteristics of patients with non-advanced HCC have changed over time. Appropriate background liver management led to better liver-related prognoses in BCLC 0/A.

Prognostic significance of C-reactive protein in unresectable hepatocellular carcinoma treated with atezolizumab and bevacizumab.

AIM: C-reactive protein (CRP) is both an inflammatory and prognostic marker in various cancers. This study aimed to elucidate the characteristics of CRP and the prognostic factors in patients who were administered with atezolizumab plus bevacizumab (ATZ + BEV) for unresectable hepatocellular carcinoma (HCC). METHODS: A total of 213 patients who received ATZ + BEV for HCC from November 2020 to March 2023 at 15 hospitals were enrolled in this retrospective study. The prognosis was analyzed by subdividing the patients based on baseline characteristics, radiologic response, and treatment lines. Accuracy of survival prediction was assessed using CRP, alpha fetoprotein (AFP), C-reactive protein and alpha fetoprotein in immunotherapy (CRAFITY), and Glasgow Prognostic Score. RESULTS: Compared with patients with baseline CRP <1 mg/dL, those with baseline CRP ≥1 mg/dL (n = 45) had a significantly higher baseline albumin-bilirubin score and AFP levels, significantly lower disease control rate (62.2%), and significantly shorter median overall survival (hazards ratios 2.292; 95% confidence interval 1.313-5.107; log-rank test, p < 0.001). Multivariate analysis identified CRP ≥1 mg/dL, AFP ≥100 ng/mL, and modified albumin-bilirubin grade as the significant prognostic factors. The baseline CRP, AFP, CRAFITY, and Glasgow Prognostic Score demonstrated higher discrimination for 1-year survival prediction after first-line ATZ + BEV administration, compared with beyond second line, with area under the receiver operating characteristic curves of 0.759, 0.761, 0.805, and 0.717, respectively. CONCLUSIONS: CRP was a significant biomarker in patients treated with ATZ + BEV for HCC. Elevated CRP levels may indicate aggressive cancer progression and potential resistance to ATZ + BEV therapy.

Factors associated with liver injury and prognosis in advanced cancer patients treated with immune checkpoint inhibitors.

AIM: The use of immune checkpoint inhibitors (ICIs) has increased remarkably, and immune-related adverse events (irAEs) have also increased. This study aimed to identify factors associated with immune-related liver injury (irLI), and the relationship between the grades of irLI and overall survival (OS) in patients treated with ICIs. METHODS: A total of 571 patients who had been treated for advanced malignancies with ICIs between January 2015 and March 2022 were retrospectively recruited. The presence of liver injury was determined by the aspartate aminotransferase and alanine aminotransferase elevation. The irLI grading was based on Common Terminology Criteria for Adverse Events version 5.0. RESULTS: A total of 50 (8.8%) patients had grade ≥2 irLI and 24 (4.2%) had grade ≥3 irLI. Treatment with anti-cytotoxic T-lymphocyte-associated protein-4 agents and baseline grade 1 aspartate aminotransferase/alanine aminotransferase elevation were independent predictive factors of grade ≥2 irLI. Treatment with anti-cytotoxic T-lymphocyte-associated protein-4 was the only independent predictive factor of grade ≥3 irLI. The median OS for patients who experienced any irAEs was significantly longer than of those without irAEs (hazard ratio 0.503, 95% CI 0.398-0.636, p < 0.001). The median OS in patients with grade ≥2 irLI was significantly longer (HR 0.570, 95% CI 0.387-0.838, p = 0.022). There was no significant difference between the median OS in patients with grade ≥3 irLI and the others (p = 0.11). CONCLUSION: The incidence of irLI was significantly higher in patients treated with anti-cytotoxic T-lymphocyte-associated protein-4 agents. Even in patients with pre-existing grade 1 aspartate aminotransferase/alanine aminotransferase elevation, appropriate follow-up and control of the irLI can improve the prognosis.

Impact of eradication of hepatitis C virus on liver-related and -unrelated diseases: morbidity and mortality of chronic hepatitis C after SVR.

Hepatitis C virus infection is characterized by chronic liver inflammation and fibrogenesis, leading to end-stage liver failure and hepatocellular carcinoma over the course of 20 to 30 years. It seems not only the chronicity of hepatitis C but also the presence of the virus in non-hepatic tissues creates a favorable environment for the potential development of pathogenic impacts on extrahepatic systems and organs. Numerous extra-hepatic manifestations have been reported in association with HCV infection, all of which can substantially affect morbidity, mortality, and quality of life. With the recent development of DAAs, antiviral treatment can cure almost all patients with HCV infection, even those intolerant of or unresponsive to IFN treatment, and several large multicenter studies have confirmed the association of DAA-induced SVR with reductions in liver-related and liver-unrelated complications, such as cardiovascular events, end stage renal disease, and so on. Because, in addition to liver-related diseases, extrahepatic lesions are threatening for patients, it is important to eradicate the virus before these progress and affect life prognosis; in other words, patients should be treated before reaching the point of no return. Tailored surveillance with biomarkers such as M2BPGi and Ang-2, which can be used to identify patients with an elevated risk of EHM, and early prevention or treatment for these patients could improve the morbidity, mortality and QOL. Advancement of both basic and clinical research in this field including the development of more precise biomarkers is highly anticipated.

Suspension culture in a rotating bioreactor for efficient generation of human intestinal organoids.

Human intestinal organoids (HIOs) derived from human pluripotent stem cells (hPSCs) hold great promise for translational medical applications. A common method to obtain HIOs has been to harvest floating hindgut spheroids arising from hPSCs. As this technique is elegant but burdensome due to the complex protocol and line-to-line variability, a more feasible method is desired. Here, we establish a robust differentiation method into suspension-cultured HIOs (s-HIOs) by seeding dissociated cells on a spheroid-forming plate. This protocol realizes the reliable generation of size-controllable spheroids. Under optimized conditions in a rotating bioreactor, the generated spheroids quickly grow and mature into large s-HIOs with supporting mesenchyme. Upon mesenteric transplantation, s-HIOs further mature and develop complex tissue architecture in vivo. This method demonstrates that intestinal tissue can be generated from iPSC-derived HIOs via suspension induction and bioreactor maturation, establishing a reliable culture platform with wide applications in regenerative medicine.

Mac-2 binding protein glycosylation isomer as a novel predictive biomarker for patient survival after hepatitis C virus eradication by DAAs.

BACKGROUND: It is crucial to identify risk factors for life prognosis after hepatitis C virus (HCV) eradication among patients with or without a high risk of liver cancer or complications. METHODS: This is a prospective, multicenter and observational study using the database of 1031 patients after HCV eradication by direct-acting antiviral agents (DAAs) to evaluate the development of hepatocellular carcinoma (HCC) and patients' survival after a sustained virological response (SVR). The Cox proportional hazards regression model was used to estimate hazard ratios associated with HCC development and survival. RESULTS: AFP at SVR was significantly associated with HCC recurrence in the adjusted model. Liver fibrosis, Mac-2 binding protein glycosylation isomer (M2BPGi) at SVR and smoking status before treatment were positively associated with the development of HCC and M2BPGi was positively associated with HCC recurrence, although not reaching statistical significance. Among patients without a history of HCC, M2BPGi and estimated glomerular filtration rate (eGFR) at SVR were significantly associated with death after viral eradication [M2BPGi (HR 4.07, 95% CI 1.22, 13.57), eGFR (HR 0.97, 95% CI 0.94, 0.99)]. Strikingly, of 16 patients who died, among participants without a history of HCC, only two died of liver cancer associated with HCV, whereas 11 died of non-HCV- related cancer or cardiovascular diseases. CONCLUSION: M2BPGi at SVR is a potential predictor for patients' survival and a candidate biomarker for detecting individuals who are at greater risk of death due to cancer-related and unrelated to HCV, as well as cardiovascular diseases, after viral eradication.

Vasoactive Intestinal Peptide Derived From Liver Mesenchymal Cells Mediates Tight Junction Assembly in Mouse Intrahepatic Bile Ducts.

Formation of intrahepatic bile ducts (IHBDs) proceeds in accordance with their microenvironment. Particularly, mesenchymal cells around portal veins regulate the differentiation and ductular morphogenesis of cholangiocytes in the developing liver; however, further studies are needed to fully understand the arrangement of IHBDs into a continuous hierarchical network. This study aims to clarify the interaction between biliary and liver mesenchymal cells during IHBD formation. To identify candidate factors contributing to this cell-cell interaction, mesenchymal cells were isolated from embryonic day 16.5 matrix metalloproteinase 14 (MMP14)-deficient (knockout [KO]) mice livers, in which IHBD formation is retarded, and compared with those of the wild type (WT). WT mesenchymal cells significantly facilitated the formation of luminal structures comprised of hepatoblast-derived cholangiocytes (cholangiocytic cysts), whereas MMP14-KO mesenchymal cells failed to promote cyst formation. Comprehensive analysis revealed that expression of vasoactive intestinal peptide (VIP) was significantly suppressed in MMP14-KO mesenchymal cells. VIP and VIP receptor 1 (VIPR1) were mainly expressed in periportal mesenchymal cells and cholangiocytic progenitors during IHBD development, respectively, in vivo. VIP/VIPR1 signaling significantly encouraged cholangiocytic cyst formation and up-regulated tight junction protein 1, cystic fibrosis transmembrane conductance regulator, and aquaporin 1, in vitro. VIP antagonist significantly suppressed the tight junction assembly and the up-regulation of ion/water transporters during IHBD development in vivo. In a cholestatic injury model of adult mice, exogenous VIP administration promoted the restoration of damaged tight junctions in bile ducts and improved hyperbilirubinemia. Conclusion: VIP is produced by periportal mesenchymal cells during the perinatal stage. It supports bile duct development by establishing tight junctions and up-regulating ion/water transporters in cholangiocytes. VIP contributes to prompt recovery from cholestatic damage through the establishment of tight junctions in the bile ducts.

Analysis of the mechanism underlying liver diseases using human induced pluripotent stem cells.

Results of recent studies have shown that disease models using human induced pluripotent stem (iPS) cells have recapitulated the pathophysiology of genetic liver diseases, viral hepatitis and hepatic fibrosis. The utilization of human iPS cells as a model of liver diseases has several substantial advantages compared with primary hepatocytes and cancer cell lines, such as the potential for unlimited expansion and similarity of biological characteristics to normal liver cells. In this review, we have focused on modeling liver diseases using human iPS cells and discussed the experimental evidence that supports the utility of such disease models, including that in our recent studies. Genetically modified or patient-derived human iPS cells can mimic congenital liver disease phenotypes. Human iPS-derived hepatic cells can be infected with the hepatitis viruses. The co-culture of human iPS-derived hepatocytes and mesenchyme partially mimics the process of liver fibrosis. Human iPS cell-derived hepatic cells and the co-culture system of such cells will contribute to the progress of studies on the pathophysiology of genetic and non-genetic liver diseases and development of novel therapeutic strategies for treating liver diseases.

Comprehensive genetic analysis of cholangiolocellular carcinoma with a coexistent hepatocellular carcinoma-like area and metachronous hepatocellular carcinoma.

AIM: The genetic profile of cholangiolocellular carcinoma (CLC) and its origin in relation to hepatocellular carcinoma (HCC) remain unclear. To elucidate the genetic profile of CLC, a comprehensive analysis of genetic mutations was carried out in a case of CLC with an HCC-like focal area and metachronous HCC. METHOD: Liver tissue was obtained from CLC, a co-existent HCC-like area, and metachronously developed HCC by laser capture microdissection of formalin-fixed paraffin-embedded specimens obtained by hepatectomy. Gene mutational profiles were analyzed comprehensively by next-generation sequencing and digital PCR. Relationships among gene profiles, immunohistochemistry, and clinicopathological findings were investigated. RESULTS: Mutations in EGFR, PTEN, RB1, TP53, and ERBB2 were found in CLC, whereas mutations in KIT, BRAF, PTEN, TP53, and SMAD4 were found in the coexistent HCC-like area. Only the mutation in PTEN has a common Catalogue of Somatic Mutations in Cancer ID in the CLC and coexistent HCC-like area, and is related to the kinase-RAS module. In contrast, no cancer-related mutations were found in the metachronous HCC. No TERT mutations were found in any of the regions by digital PCR. Immunohistochemical staining for p53 was negative in CLC, although ≤10% positive in the coexistent HCC-like area. Immunostaining of C-kit, HER2, PTEN, and SMAD4 were negative. CONCLUSION: The genomic features of CLC and the focal area of an HCC-like region differ, but are related to the kinase-RAS module. The development of carcinogenesis in the CLC and HCC-like areas in this case might differ, following a common PTEN mutation, although alteration of the kinase-RAS module is the most common molecular event in CLC.

Loss of fibrocystin promotes interleukin-8-dependent proliferation and CTGF production of biliary epithelium.

BACKGROUND & AIMS: Congenital hepatic fibrosis (CHF) is a genetic liver disease resulting in abnormal proliferation of cholangiocytes and progressive hepatic fibrosis. CHF is caused by mutations in the PKHD1 gene and the subsequent dysfunction of the protein it encodes, fibrocystin. However, the underlying molecular mechanism of CHF, which is quite different from liver cirrhosis, remains unclear. This study investigated the molecular mechanism of CHF pathophysiology using a genetically engineered human induced pluripotent stem (iPS) cell model to aid the discovery of novel therapeutic agents for CHF. METHODS: PKHD1-knockout (PKHD1-KO) and heterozygously mutated PKHD1 iPS clones were established by RNA-guided genome editing using the CRISPR/Cas9 system. The iPS clones were differentiated into cholangiocyte-like cells in cysts (cholangiocytic cysts [CCs]) in a 3D-culture system. RESULTS: The CCs were composed of a monolayer of cholangiocyte-like cells. The proliferation of PKHD1-KO CCs was significantly increased by interleukin-8 (IL-8) secreted in an autocrine manner. IL-8 production was significantly elevated in PKHD1-KO CCs due to mitogen-activated protein kinase pathway activation caused by fibrocystin deficiency. The production of connective tissue growth factor (CTGF) was also increased in PKHD1-KO CCs in an IL-8-dependent manner. Furthermore, validation analysis demonstrated that both the serum IL-8 level and the expression of IL-8 and CTGF in the liver samples were significantly increased in patients with CHF, consistent with our in vitro human iPS-disease model of CHF. CONCLUSIONS: Loss of fibrocystin function promotes IL-8-dependent proliferation of, and CTGF production by, human cholangiocytes, suggesting that IL-8 and CTGF are essential for the pathogenesis of CHF. IL-8 and CTGF are candidate molecular targets for the treatment of CHF. LAY SUMMARY: Congenital hepatic fibrosis (CHF) is a genetic liver disease caused by mutations of the PKHD1 gene. Dysfunction of the protein it encodes, fibrocystin, is closely associated with CHF pathogenesis. Using an in vitro human induced pluripotent stem cell model and patient samples, we showed that the loss of fibrocystin function promotes proliferation of cholangiocytes and the production of connective tissue growth factor (CTGF) in an interleukin 8 (IL-8)-dependent manner. These results suggest that IL-8 and CTGF are essential for the pathogenesis of CHF.

Diabetic Retinopathy as a Risk Factor Associated with the Development of Hepatocellular Carcinoma in Nonalcoholic Fatty Liver Disease.

BACKGROUND: The risk factors associated with the development of hepatocellular carcinoma (HCC) in nonalcoholic fatty liver disease (NAFLD) are still unclear. The aim of the present study was to identify such risk factors in NAFLD patients who developed HCC. METHODS: Between April 2000 and -December 2016, a total of 182 patients with NAFLD were enrolled in this study; of these, only 22 patients had HCC. To identify risk factors, univariate and multivariate analyses were performed. To identify risk factors other than the degree of fibrosis, propensity matched analysis adjusted by the NAFLD fibrosis score (NFS) was carried out on 44 patients. Multivariate and survival analyses were also performed in HCC patients. RESULTS: In 182 patients, multivariate analysis highlighted the NFS (OR 2.275; p < 0.001) and hypertension (OR 5.868; p = 0.037) as independent factors that were significantly associated with the development of HCC. After adjustment for the NFS, multivariate analysis identified diabetic retinopathy (OR 8.654; p = 0.017) as an independent factor that was significantly associated with the development of HCC. For predicting the development of HCC, the area under the receiver operating characteristic curve of diabetic retinopathy was significantly higher than that of diabetes (0.731 vs. 0.615; p < 0.001). In patients with HCC, multivariate analysis indicated that the NFS were significantly associated with diabetic retinopathy. CONCLUSIONS: Diabetic retinopathy as well as liver fibrosis is a risk factor that associates with the development of HCC in NAFLD patients. Therefore, NAFLD patients with diabetic retinopathy should undergo careful screening for HCC.

Association of serum interferon-λ3 levels with hepatocarcinogenesis in chronic hepatitis C patients treated with direct-acting antiviral agents.

AIM: Although the efficacy of hepatitis C virus (HCV) treatment is improved dramatically by direct-acting antiviral agents (DAAs), the assessment of hepatocellular carcinoma (HCC) remains important. Interferon lambda 3 (IFN-λ3) is associated with liver fibrosis and inflammation in chronic hepatitis C (CHC) patients, but its impact on carcinogenesis remains controversial and little is known about its effects after viral clearance. To determine the contribution of IFN-λ3 to hepatocarcinogenesis after HCV clearance, we analyzed IFNL3 genotypes and serial serum IFN-λ3 levels in CHC patients who achieved sustained virologic responses (SVR). METHODS: This study comprised 201 CHC patients treated with DAAs. Serum samples were collected sequentially and IFN-λ3 levels were quantified by chemiluminescence enzyme immunoassay. The IFNL3 polymorphism (rs8099917) was genotyped in 195 patients. RESULTS: One hundred and twenty-five patients were rs8099917 T/T and 70 were non-T/T. Serum IFN-λ3 levels did not differ significantly with IFNL3 genotype, dropped markedly by 1 week and remained low up to 24 weeks after the end of treatment. Interferon-λ3 levels were significantly higher after viral clearance in patients who developed HCC and were associated with a higher potential for hepatocarcinogenesis, such as a higher frequency of non-hypervascular hypointensive nodules (P = 0.046), higher stages of liver fibrosis (P < 0.001), and higher post-treatment levels of Wisteria floribunda agglutinin positive Mac-2 binding protein (P < 0.001) and alanine aminotransferase (P < 0.001). CONCLUSIONS: Serum IFN-λ3 levels after HCV clearance are associated with the potential for HCC development. Interferon-λ3 could be helpful for elucidating the relationships among immunologic status, liver fibrosis, liver inflammation, and hepatocarcinogenesis, after achieving SVR.

A Rodent Model for Cell Transplantation of Hepatic Progenitor Cells.

Hepatic progenitor cells are defined as cells exhibiting potency for active proliferation and capacity for bipotential differentiation into hepatocytes and cholangiocytes. To prove the capacity of target cells for terminal differentiation and reconstitution of organs, cell transplantation models have been widely used in previous studies, including those involving the liver. Here we describe a protocol for transplantation of hepatic progenitor cells using retrorsine pretreatment and partial hepatectomy. This transplantation assay reveals the potential for reconstitution of hepatocytes in recipient livers by primary hepatic progenitor cells. Donor cells are detected as a colony composed of 5-10 mature hepatocytes.

Effect of interferon-based and -free therapy on early occurrence and recurrence of hepatocellular carcinoma in chronic hepatitis C.

BACKGROUND AND AIMS: Although treatment for hepatitis C virus has been dramatically improved by the development of direct-acting antiviral agents (DAAs), whether interferon (IFN)-free therapy reduces hepatocarcinogenesis in an equivalent manner to IFN-based therapy remains controversial. The aims of this study were to evaluate the occurrence and recurrence of hepatocellular carcinoma (HCC) in chronic hepatitis C (CHC) patients treated with DAAs and to identify biomarkers of HCC development after antiviral treatment. METHODS: A restrospective review of a prospective database of 1,897 CHC patients who were treated with IFN-based (1,145) or IFN-free therapies (752) was carried out. Cumulative HCC occurrence and recurrence rates were compared using propensity score-matched analysis. Predictors of HCC development after viral eradication were identified by multivariate analysis. RESULTS: Propensity score-matched analysis showed no significant difference in HCC occurrence (p=0.49) and recurrence rates (p=0.54) between groups treated with IFN-based or IFN-free therapies. In multivariate analysis, higher levels of post-treatment α-fetoprotein (AFP) or Wisteria floribunda agglutinin positive Mac-2 binding protein (WFA+M2BP) were independently associated with HCC occurrence and recurrence after viral eradication. Only post-treatment WFA+M2BP level was significantly associated with HCC occurrence and recurrence among patients without severe fibrosis. The area under the receiver operating characteristic (ROC) curve for WFA+M2BP levels was greater than that for AFP levels in ROC analysis. CONCLUSION: The risks of early HCC occurrence and recurrence after viral eradication were similar between IFN-based and IFN-free therapies. Post-treatment levels of WFA+M2BP may be helpful screening biomarkers for assessing the risk of HCC after IFN-free therapy. Patients with high WFA+M2BP levels after antiviral treatment, even without severe fibrosis, must be followed up carefully for HCC development. Lay summary: The risks of early HCC occurrence and recurrence after viral eradication were similar between IFN-based and IFN-free therapies. Post-treatment levels of WFA+M2BP may be helpful screening biomarkers for assessing the risk of HCC after IFN-free therapy.

Bone morphogenetic protein-4 modulates proliferation and terminal differentiation of fetal hepatic stem/progenitor cells.

Fetal hepatic stem/progenitor cells, called hepatoblasts, play central roles in liver organogenesis; however, molecular mechanisms regulating proliferation and terminal differentiation of such cells have not been completely elucidated. Bone morphogenetic protein-4 (BMP-4) is essential for the development of stem cells in various tissues, but its function in regulating the phenotype of hepatoblasts after the mid-gestational fetal stage remains unclear. The aim of this study is to clarify a functional role for BMP-4 in proliferation and terminal differentiation of murine hepatoblasts in mid-gestational fetal livers. METHODS: A functional role for BMP-4 in proliferation and terminal differentiation of murine hepatoblasts was validated by assay of colony formation, biliary luminal formation, and hepatic maturation using primary hepatoblasts in vitro. Molecular mechanisms regulating such effects of BMP-4 on primary hepatoblasts were also analyzed. RESULTS: Stimulation of BMP-4 upregulated phosphorylation of Smad1/5 in hepatoblasts. Bone morphogenetic protein-4 significantly suppressed colony formation of primary hepatoblasts in a dose-dependent manner, significantly suppressed cholangiocytic luminal formation of hepatoblasts, and promoted hepatic maturation of primary hepatoblasts. Stimulation of BMP-4 regulated the activation of several mitogen-activated protein kinases, such as extracellular signal-regulated kinase, Akt, p38 mitogen-activated protein kinase, and calcium/calmodulin-dependent protein kinase IIα in primary hepatoblasts. Moreover, Wnt5a, a molecule regulating cholangiocytic luminal formation, and BMP-4 coordinately suppressed proliferation and cholangiocytic luminal formation of hepatoblasts. CONCLUSION: This study shows that BMP-4-mediated signaling controls proliferation and terminal differentiation of fetal hepatic stem/progenitor cells.

Chronic Hepatitis E Infection in a Persistently Immunosuppressed Patient Unable to Be Eliminated after Ribavirin Therapy.

Recent case reports have shown that hepatitis E virus (HEV) infection can cause chronic hepatitis in immunosuppressed or immunocompromised patients. A 37-year-old woman suffered from prolonged elevation of aminotransferases after chemotherapy for Burkitt's lymphoma and was diagnosed with chronic hepatitis E due to a transfusion during chemotherapy. After an 8-month administration of ribavirin, complete HEV clearance was not achieved, likely due to prolonged hypogammaglobulinemia. This case indicates that HEV infection should be ruled out during liver dysfunction in immunosuppressed or immunocompromised patients and suggests that an alternative therapeutic strategy for such patients will be needed.

Serial measurement of Wisteria floribunda agglutinin positive Mac-2-binding protein is useful for predicting liver fibrosis and the development of hepatocellular carcinoma in chronic hepatitis C patients treated with IFN-based and IFN-free therapy.

AIM: Wisteria floribunda agglutinin positive (WFA+) Mac-2-binding protein (M2BPGi) is a noninvasive glyco-marker for liver fibrosis. This study evaluated the utility of serial measurement of serum M2BPGi and total M2BP as a predictor of fibrosis and the development of hepatocellular carcinoma (HCC). METHODS: This study included 119 patients with chronic hepatitis C (CHC). Of these patients, 97 were treated with IFN-based therapy and 22 were treated with daclatasvir and asunaprevir. Serum M2BPGi values were measured prior to, at the end of, and at 24 weeks after the completion of treatment. As subanalysis, serum total M2BP levels were measured in patients treated with pegylated-interferon and ribavirin. RESULTS: In patients treated with IFN-based therapy, M2BPGi levels were elevated at the end of treatment but decreased afterwards. In contrast, M2BPGi levels in patients treated with IFN-free therapy decreased immediately after starting the treatment without transient elevation. Though pre-treatment M2BPGi levels significantly correlated with fibrosis in both patients with a sustained virological response (SVR) and non-SVR, post-treatment M2BPGi levels decreased regardless of the degree of fibrosis in patients with SVR. In multivariate analysis, non-SVR and HCC development were independent factors associated with M2BPGi level ≥2.2. In patients treated with pegylated-interferon and ribavirin, total M2BP levels were positively correlated with fibrosis and HCC development. CONCLUSION: Real-time monitoring of the serum M2BPGi level after antiviral therapy for CHC patients could be a helpful screening tool for assessing the risk of HCC. M2BP and its glycan structure could be associated together with hepatocarcinogenesis.

Human induced pluripotent stem cell-derived hepatic cell lines as a new model for host interaction with hepatitis B virus.

Hepatitis B virus (HBV) is not eradicated by current antiviral therapies due to persistence of HBV covalently closed circular DNA (cccDNA) in host cells, and thus development of novel culture models for productive HBV infection is urgently needed, which will allow the study of HBV cccDNA eradication. To meet this need, we developed culture models of HBV infection using human induced pluripotent stem cell-derived hepatocyte lineages, including immature proliferating hepatic progenitor-like cell lines (iPS-HPCs) and differentiated hepatocyte-like cells (iPS-Heps). These cells were susceptible to HBV infection, produced HBV particles, and maintained innate immune responses. The infection efficiency of HBV in iPS-HPCs predominantly depended on the expression levels of sodium taurocholate cotransporting polypeptide (NTCP), and was low relative to iPS-Heps: however, long-term culture of iPS-Heps was difficult. To provide a model for HBV persistence, iPS-HPCs overexpressing NTCP were established. The long-term persistence of HBV cccDNA was detected in iPS-HPCs overexpressing NTCP, and depended on the inhibition of the Janus-kinase signaling pathway. In conclusion, this study provides evidence that iPS-derived hepatic cell lines can be utilized for novel HBV culture models with genetic variation to investigate the interactions between HBV and host cells and the development of anti-HBV strategies.

Evaluation of Interferon Resistance in Newly Established Genotype 1b Hepatitis C Virus Cell Culture System.

BACKGROUND AND AIMS: The hepatitis C virus (HCV) genotype 1b is known to exhibit treatment resistance with respect to interferon (IFN) therapy. Substitution of amino acids 70 and 91 in the core region of the 1b genotype is a significant predictor of liver carcinogenesis and poor response to pegylated-IFN-α and ribavirin therapy. However, the molecular mechanism has not yet been clearly elucidated because of limitations of the HCV genotype 1b infectious model. Recently, the TPF1-M170T HCV genotype 1b cell culture system was established, in which the clone successfully replicates and infects Huh-7-derived Huh7-ALS32.50 cells. Therefore, the purpose of this study was to compare IFN resistance in various HCV clones using this system. METHODS: HCV core amino acid substitutions R70Q and L91M were introduced to the TPF1-M170T clone and then transfected into Huh7-ALS32.50 cells. To evaluate the production of each virus, intracellular HCV core antigens were measured. RESULTS were confirmed with Western blot analysis using anti-NS5A antibodies, and IFN sensitivity was subsequently measured. RESULTS: Each clone was transfected successfully compared with JFH-1, with a significant difference in intracellular HCV core antigen (p < 0.05), an indicator of continuous HCV replication. Among all clones, L91M showed the highest increase in the HCV core antigen and HCV protein. There was no significant resistance against IFN treatment in core substitutions; however, IFN sensitivity was significantly different between the wildtype core and JFH-1 (p < 0.05). CONCLUSIONS: A novel genotype 1b HCV cell culture was constructed with core amino acid substitutions, which demonstrated IFN resistance of genotype 1b. This system will be useful for future analyses into the mechanisms of HCV genotype 1b treatment.