Interferon-α suppresses hepatitis B virus enhancer II activity via the protein kinase C pathway

AbstractHBV has two enhancer (En) regions each of which promotes its own transcription. En II regulates production of pregenomic RNA, a key product of HBV replication, more strongly than En I. Although IFN-α has been found to suppress En I activity, its effect on En II activity has not been examined. Here we used luciferase assay to demonstrate that IFN-α suppresses En II activity. Analysis with several deletion/mutation constructs identified two major segments, nt 1703–1727 and nt 1746–1770, within the En II sequence as being responsible for the suppressive effects of IFN-α. Pre-treatment with protein kinase C (PKC) inhibitors blocked this effect regardless of the expression levels of phospho-STAT1 and Mx upon IFN-α stimulation. These results indicate that IFN-α suppresses En II activity via the PKC pathway, which may be an alternative suppressive pathway for HBV replication. (136 words)

Serum growth differentiation factor 15 is a novel biomarker with high predictive capability for liver cancer occurrence in patients with MASLD regardless of liver fibrosis

Kumazaki S., Hikita H., Tahata Y., et al. Serum growth differentiation factor 15 is a novel biomarker with high predictive capability for liver cancer occurrence in patients with MASLD regardless of liver fibrosis. Alimentary Pharmacology and Therapeutics , (2024); https://doi.org/10.1111/apt.18063.Background and Aims: Although metabolic dysfunction-associated steatotic liver disease (MASLD) patients with a Fib-4 index >1.3 are recommended for fibrosis evaluation via elastography or biopsy, a more convenient method identifying high-risk populations requiring follow-up is needed. We explored the utility of serum levels of growth differentiation factor-15 (GDF15), a cell stress-responsive cytokine related to metabolic syndrome, for stratifying the risk of clinical events in MASLD patients. Methods: Serum GDF15 levels were measured in 518 biopsy-performed MASLD patients, 216 MASLD patients for validation, and 361 health checkup recipients with MASLD. Results: In the biopsy-MASLD cohort, multivariate analysis indicated that the serum GDF15 level was a risk factor for liver cancer, independent of the fibrosis stage or Fib-4 index. Using a GDF15 cutoff of 1.75 ng/mL based on the Youden index, high-GDF15 patients, regardless of fibrosis status, had a higher liver cancer incidence rate. While patients with a Fib-4 index 1.3 developed liver cancer and decompensated liver events at significantly higher rates and had poorer prognoses. In the validation cohort, high-GDF15 patients had significantly higher incidences of liver cancer and decompensated liver events and poorer prognoses than low-GDF15 patients, whether limited to high-Fib-4 patients. Among health checkup recipients with MASLD, 23.0% had a Fib-4 index >1.3, 2.7% had a Fib-4 index >1.3 and >1.75 ng/mL GDF15. Conclusions: Serum GDF15 is a biomarker for liver cancer with high predictive capability and is useful for identifying MASLD patients requiring regular surveillance

High serum growth differentiation factor 15 is a risk factor for the occurrence of hepatocellular carcinoma in chronic hepatitis B patients treated with nucleos(t)ide analogs

Sometani E., Hikita H., Murai K., et al. High serum growth differentiation factor 15 is a risk factor for the occurrence of hepatocellular carcinoma in chronic hepatitis B patients treated with nucleos(t)ide analogs. Hepatology Research, (2024); https://doi.org/10.1111/hepr.14111.Aim: Patients with chronic hepatitis B (CHB) remain at risk for hepatocellular carcinoma (HCC) even with nucleos(t)ide analog therapy. We evaluated risk factors for HCC development, including serum hepatitis B virus (HBV) RNA, hepatitis B core-related antigen level, and growth differentiation factor 15 (GDF15) level, a predictor of HCC development in patients with chronic hepatitis C. Methods: We collected clinical data and stored serum from CHB patients without a history of HCC who were receiving nucleos(t)ide analog treatment for more than 1 year and whose HBV DNA level was less than 3.0 log IU/mL. We measured the serum levels of HBV RNA and GDF15. Results: Among 242 CHB patients, 57 had detectable HBV RNA, and GDF15 was quantified in all patients. The median GDF15 level was 0.86 ng/mL. Cox proportional hazards analysis revealed that male sex and higher GDF15, FIB-4 index, alpha-fetoprotein and gamma-glutamyl transpeptidase were independent risk factors for HCC. The presence of HBV RNA above the lower limit of quantification was not a risk factor. When we set cutoff values based on the Youden index, the cumulative incidence of HCC was significantly higher in the male, AFP ≥3.0 ng/mL, gamma-glutamyl transpeptidase ≥22 U/L, FIB-4 index ≥1.93, and GDF-15 ≥1.17 ng/mL groups. In patients with no or more than three of these five risk factors, the 10-year HCC cumulative incidence rates were 0% and 41.0%, respectively. Conclusions: High serum GDF15 is an independent risk factor for the occurrence of HCC in CHB patients treated with nucleos(t)ide analogs

Mechanisms of the autophagosome-lysosome fusion step and its relation to non-alcoholic fatty liver disease

Macroautophagy (hereafter autophagy) is a catabolic process by which autophagosomes arising from an isolation membrane fuse with lysosomes to degrade components in the cytoplasm. Autophagosome-lysosome fusion step is one of the key steps during the process of macroautophagy. The step is extremely complicated and its detailed mechanisms remain unclear. It consists of two phases: first phase is autophagosome migration phase and second phase is fusion of autophagosomes and lysosomes phase. Recently, various molecules have been reported to be involved in each phase. In the first phase, microtubules and actin remodeling mechanism are involved. In the second phase, soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, Rab family proteins, phosphoinositide 3-kinase (PI3K) complex and Rubicon are involved. In the present review, we introduce recent findings related to autophagosome-lysosome fusion step and discuss liver diseases possibly associated with autophagosome-lysosome fusion dysfunction. Keywords: Autophagy, Autophagosome-lysosome fusion, Rubicon, Non-alcoholic fatty liver disease (NAFLD), Hepatitis B virus (HBV), Hepatitis C virus (HCV), Liver cance

Increased Bcl-xL Expression in Pancreatic Neoplasia Promotes Carcinogenesis by Inhibiting Senescence and ApoptosisSummary

Background & Aims: Bcl-xL, an anti-apoptotic Bcl-2 family protein, is overexpressed in 90% of pancreatic ductal adenocarcinoma (PDAC) cases. However, Bcl-xL expression in pancreatic intraepithelial neoplasias (PanINs) and its significance in PDAC carcinogenesis remain unclear. The aim of this study was to elucidate the significance of Bcl-xL expression in PanINs. Methods: We investigated the expression levels of Bcl-xL in pancreas-specific KrasG12D (P-KrasG12D) mice and human PanINs and PDAC. We examined the impact of Bcl-xL expression on Kras-mutated pancreatic neoplasia using Bcl-xLâoverexpressing P-KrasG12D mice and Bcl-xLâknockout P-KrasG12D mice. Results: In P-KrasG12D mice, the number of PanINs increased and their grades progressed with age. In total, 55.6% of these mice developed PDAC at 12â14 months. According to the immunohistochemistry of mouse pancreas and human resected specimens, Bcl-xL expression was increased significantly in PanIN-1 compared with that in normal pancreatic ducts, and augmented further with the progression of pancreatic neoplasia in PanIN-2/3 and PDAC. Oncogene-induced senescence was observed frequently in PanIN-1, but rarely was detected in PanIN-2/3 and PDAC. Bcl-xL overexpression significantly accelerated the progression to high-grade PanINs and PDAC and reduced the survival of P-KrasG12D mice. Bcl-xL overexpression in P-KrasG12D mice suppressed oncogene-induced senescence in PanIN-1 and inhibited apoptosis in PanIN-3. Bcl-xL deficiency in P-KrasG12D mice induced cellular senescence in PanIN-2/3. Conclusions: Bcl-xL expression increases with the progression from PanIN-1 to PDAC, whereas oncogene-induced senescence decreases. Bcl-xL overexpression increases PDAC incidence rates by inhibiting oncogene-induced senescence and apoptosis in PanINs. Conversely, Bcl-xL deficiency induced senescence in PanINs. AntiâBcl-xL treatments may have the potency to suppress the progression from PanINs to PDAC. Keywords: Kras, PanINs, Bcl-2 Family Protei