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.

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.

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.

Matrix metalloproteinase-14 mediates formation of bile ducts and hepatic maturation of fetal hepatic progenitor cells.

Fetal hepatic stem/progenitor cells, called hepatoblasts, play central roles in liver development; however, the molecular mechanisms regulating the phenotype of these cells have not been completely elucidated. Matrix metalloproteinase (MMP)-14 is a type I transmembrane proteinase regulating pericellular proteolysis of the extracellular matrix and is essential for the activation of several MMPs and cytokines. However, the physiological functions of MMP-14 in liver development are unknown. Here we describe a functional role for MMP-14 in hepatic and biliary differentiation of mouse hepatoblasts. MMP-14 was upregulated in cells around the portal vein in perinatal stage liver. Formation of bile duct-like structures in MMP-14-deficient livers was significantly delayed compared with wild-type livers in vivo. In vitro biliary differentiation assays showed that formation of cholangiocytic cysts derived from MMP-14-deficient hepatoblasts was completely impaired, and that overexpression of MMP-14 in hepatoblasts promoted the formation of bile duct-like cysts. In contrast, the expression of molecules associated with metabolic functions in hepatocytes, including hepatic nuclear factor 4α and tryptophan 2,3-dioxygenase, were significantly increased in MMP-14-deficient livers. Expression of the epidermal growth factor receptor and phosphorylation of mitogen-activated protein kinases were significantly upregulated in MMP-14-deficient livers. We demonstrate that MMP-14-mediated signaling in fetal hepatic progenitor cells promotes biliary luminal formation around the portal vein and negatively controls the maturation of hepatocytes.

Purification, characterization, and primary structure of a novel N-acyl-D-amino acid amidohydrolase from Microbacterium natoriense TNJL143-2.

A novel N-acyl-D-amino acid amidohydrolase (DAA) was purified from the cells of a novel species of the genus Microbacterium. The purified enzyme, termed AcyM, was a monomeric protein with an apparent molecular weight of 56,000. It acted on N-acylated hydrophobic D-amino acids with the highest preference for N-acetyl-D-phenylalanine (NADF). Optimum temperature and pH for the hydrolysis of NADF were 45°C and pH 8.5, respectively. The k(cat) and K(m) values for NADF were 41 s⁻¹ and 2.5 mM at 37°C and pH 8.0, although the enzyme activity was inhibited by high concentrations of NADF. Although many known DAAs are inhibited by 1 mM EDTA, AcyM displayed a 65% level of its full activity even in the presence of 20 mM EDTA. Based on partial amino acid sequences of the purified enzyme, the full-length AcyM gene was cloned and sequenced. It encoded a protein of 495 amino acids with a relatively low sequence similarity to a DAA from Alcaligenes faecalis DA1 (termed AFD), a binuclear zinc enzyme of the α/ß-barrel amidohydrolase superfamily. The unique cysteine residue that serves as a ligand to the active-site zinc ions in AFD and other DAAs was not conserved in AcyM and was replaced by alanine. AcyM was the most closely related to a DAA of Gluconobacter oxydans (termed Gox1177) and phylogenetically distant from AFD and all other DAAs that have been biochemically characterized thus far. AcyM, along with Gox1177, appears to represent a new phylogenetic subcluster of DAAs.