Hepatitis B virus (HBV) infection is a major factor in development of various liver diseases such as hepatocellular carcinoma (HCC). Among HBV encoded proteins, HBV X protein (HBx) is known to play key role in development of HCC. Hepatocyte nuclear factor 4α (HNF4α) is a nuclear transcription factor which is critical for hepatocyte differentiation. However, the expression level as well as its regulatory mechanism in HBV infection have yet to be clarified. Here, we observed the suppression of HNF4α in cells which stably express HBV whole genome or HBx protein alone, while transient transfection of HBV replicon or HBx plasmid had no effect on the HNF4α level. Importantly, in the stable HBV- or HBx-expressing hepatocytes, the downregulated level of HNF4α was restored by inhibiting ERK signaling pathway. Our data showed that HNF4α was suppressed during long-term HBV infection in cultured HepG2-NTCP cells as well as in mouse model following hydrodynamic injection of pAAV-HBV or in mice intravenously infected with rAAV-HBV. Importantly, HNF4α downregulation increased cell proliferation which contributed to the formation and development of tumor in xenograft nude mice. The data presented here provided several proofs for the effect of HBV infection in manipulating HNF4α regulatory pathway in HCC development.

Abstract: Non-alcoholic fatty liver disease (NAFLD) begins with lipid accumulation within hepatocytes, but the relative contributions of different macronutrients is still unclear. We inves-tigated the impact of fatty acids, glucose and fructose on lipid accumulation in primary human hepatocytes (PHH) and three different hepatoma cell lines: HepG2, Huh7 and McA-RH7777 (McA). Cells were treated for 48 hours with fatty acids (0 or 200μM), glucose (5mM or 11mM) and fructose (0mM, 2mM or 8mM). Lipid accumulation was measured via Nile Red staining. All cell types accumulated lipid in response to fatty acids (P<0.001). PHH and McA, but not HepG2 or Huh7 cells, accumulated more lipid with 11mM glucose plus fatty acids (P=0.004, fatty acid x glucose interaction, for both), but only PHH increased lipid accumulation in response to fructose (P<0.001). Considerable variation was observed between PHH cells from different individuals. Lipid accumulation in PHH was increased by insulin (P=0.003) with inter-individual variability. Similarly, insulin increased lipid accumulation in both HepG2 and McA cells, with a bigger response in McA in the presence of fatty acids (P<0.001 for fatty acid x insulin). McA were more insulin sensitive than either HepG2 or Huh7 cells in terms of AKT phosphorylation (P<0.001 insulin x cell type interaction). Hence glucose and fructose can contribute to the accumulation of lipid in PHH with considerable inter-individual variation, but hepatoma cell lines are not good models of PHH.

We aimed to evaluate the magnesium content in human cirrhotic liver and its correlation with serum AST levels, expression of hepatocellular injury, and MELDNa prognostic score. In liver biopsies obtained at liver transplantation we measured the magnesium content in liver tissue in 27 cirrhotic patients (CIRs) and 16 deceased donors with healthy liver (CTRLs) by atomic absorption spectrometry and within hepatocytes in 15 CIRs using synchrotron-based X-ray Fluorescence Microscopy. In 31 CIRs and 10 CTRLs we evaluated the immunohistochemical expression in hepatocytes of the transient receptor potential melastatin 7 (TRPM7), a magnesium influx chanzyme also involved in inflammation. CIRs showed a lower hepatic magnesium content [117.2 (IQR 110.5-132.9) vs 162.8 (IQR 155.9-169.8) μg/g; p&lt;0.001] and a higher percentage of TRPM7 positive hepatocytes [53.0 (IQR 36.8-62.0) vs 20.7 (10.7-32.8) %; p&lt;0.001) than CTRLs. In CIRs, MELDNa and serum AST at transplant correlated: a) inversely with the magnesium content both in liver tissue and hepatocytes; b) directly with the percentage of hepatocytes stained intensely for TRPM7. The latter also directly correlated with worsening of MELDNa at transplant compared to waitlisting. Magnesium depletion and overexpression of its influx chanzyme TRPM7 in hepatocytes are associated with severity of hepatocyte injury and prognosis in cirrhosis. These data represent the pathophysiological basis for a possible beneficial effect of magnesium supplementation in cirrhotic patients.

Theaflavins, the characteristic and bioactive polyphenols in black tea, possess the potential improvement effects on insulin resistance-associated metabolic abnormalities including obesity and type 2 diebetes. However, the molecular mechanisms of theaflavins improving insulin sensitivity are still not clear. In this study, we investigated the protective effects and mechanisms of theaflavins on palmitic acid-induced insulin resistance in HepG2 cells. Theaflavins could significantly increase glucose uptake of insulin-resistant cells at noncytotoxic doses. This activity was mediated by upregulating the glucose transporter 4 protein expression, increasing the phosphorylation of IRS-1 at Ser307, and reduced the phosphor-Akt (Ser473) level. Moreover, theaflavins were found to enhance mitochondrial DNA copy number through down-regulate the PGC-1β mRNA level and up-regulate PRC mRNA expression in insulin-resistant HepG2 cells. These results indicated that theaflavins could improve free fatty acid-induced hepatic insulin resistance by promoting mitochondrial biogenesis, and were promising functional food and medicines for insulin resistance-related disorders.

Non-alcoholic fatty liver disease (NAFLD) has emerged as a significant liver ailment attributed to factors like obesity and diabetes. While ongoing research explores treatments for NAFLD, further investigation is imperative to address this escalating health concern. NAFLD manifests as hepatic steatosis, precipitating insulin resistance and metabolic syndrome. This study aims to validate the regenerative potential of chimeric fibroblast growth factor 21 (FGF21)-Hepatocyte Growth Factor Receptor (HGFR) in NAFLD-afflicted liver cells. AML12, a murine hepatocyte cell line, was utilized to gauge the regenerative effects of chimeric FGF21/HGFR expression. Polysaccharide accumulation was affirmed through periodic acid-Schiff (PAS) staining, while LDL uptake was microscopically observed with labeled LDL. mRNA analysis via RT-PCR revealed reduced expression of key NAFLD markers, including acetyl-CoA carboxylase 1 (ACC1) and sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP), alongside elevated levels of hepatocyte growth factor (HGF), hepatocyte nuclear factor 4 alpha (HNF4A), and albumin (ALB). These findings affirm the hepatoregenerative properties of chimeric FGF21/HGFR within AML12 cells, opening novel avenues for NAFLD therapeutic exploration.