Hepatitis B virus alters the antioxidant system in transgenic mice and sensitizes hepatocytes to Fas signaling

Influence of C107R mutation from hepatitis B virus genotype H on in vitro hepatitis B surface antigen detection and IFN-β-1a treatment

Aim: Assess the in vitro effect of hepatitis B virus (HBV) genotype H (HBV/H) with the small surface HBV protein (HBs) C107R mutation on hepatitis B surface antigen (HBsAg) detection, TGFB1, CAT and IFNB1A expression, and the response to IFN-β-1a treatment. Methods: HBV/H wild-type and HBs  C107R variant replicons were constructed and transfected into hepatic stellate cells and/or Huh7 that were later treated with IFN-β-1a. HBsAg, HBV-DNA, pgRNA, TGFB1, CAT and IFNB1A expression was analyzed. 3D HBs structure from wild-type and C107R were foreseen by AlphaFold protein predictor, and IFN-β-1a antiviral effect was evaluated. Results: C107R mutation did not impact viral replication, but HBsAg serologic detection was affected. Wild-type and C107R similarly modified gene expression and responded to IFN-β-1a. Conclusion: C107R disrupts the Cys107/Cys138 disulfide bond and impairs HBsAg detection. Independently of the mutation, there were changes in TGFB1, CAT and IFNB1A expression, and a medium response to IFN-β-1a treatment compared with genotype A and C.

Signaling Induced by Chronic Viral Hepatitis: Dependence and Consequences

Chronic viral hepatitis is a main cause of liver disease and hepatocellular carcinoma. There are striking similarities in the pathological impact of hepatitis B, C, and D, although these diseases are caused by very different viruses. Paired with the conventional study of protein-host interactions, the rapid technological development of -omics and bioinformatics has allowed highlighting the important role of signaling networks in viral pathogenesis. In this review, we provide an integrated look on the three major viruses associated with chronic viral hepatitis in patients, summarizing similarities and differences in virus-induced cellular signaling relevant to the viral life cycles and liver disease progression.

Changes in Glutathione Content in Liver Diseases: An Update

Glutathione (GSH), a tripeptide particularly concentrated in the liver, is the most important thiol reducing agent involved in the modulation of redox processes. It has also been demonstrated that GSH cannot be considered only as a mere free radical scavenger but that it takes part in the network governing the choice between survival, necrosis and apoptosis as well as in altering the function of signal transduction and transcription factor molecules. The purpose of the present review is to provide an overview on the molecular biology of the GSH system; therefore, GSH synthesis, metabolism and regulation will be reviewed. The multiple GSH functions will be described, as well as the importance of GSH compartmentalization into distinct subcellular pools and inter-organ transfer. Furthermore, we will highlight the close relationship existing between GSH content and the pathogenesis of liver disease, such as non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), chronic cholestatic injury, ischemia/reperfusion damage, hepatitis C virus (HCV), hepatitis B virus (HBV) and hepatocellular carcinoma. Finally, the potential therapeutic benefits of GSH and GSH-related medications, will be described for each liver disorder taken into account.

Oxidative Stress-Related Gene Polymorphisms Are Associated With Hepatitis B Virus-Induced Liver Disease in the Northern Chinese Han Population

Oxidative stress is closely related to the occurrence and development of various diseases such as cancer, diabetes, and cardiovascular and infectious diseases. We identified six critical genetic variants related to oxidative stress, and evaluated their main effects and their interaction effects on hepatitis B virus (HBV)-induced liver diseases. We enrolled 3,128 Han Chinese subjects into five groups: healthy controls, chronic hepatitis B (CHB), liver cirrhosis (LC), hepatocellular carcinoma (HCC), and natural clearance. We then determined the genotypes in each group for CYBA-rs4673, NCF4-rs1883112, NOX4-rs1836882, rs3017887, SOD2-rs4880, and GCLM-rs41303970, and evaluated the association between these variants and HBV-induced liver diseases. Gene-gene interactions were evaluated using generalized multifactor dimensionality reduction, logistic regression, and four-by-two tables. Significant associations were observed between healthy controls and the CIB group (CHB+LC+HCC). The CYBA-rs4673AG genotype was associated with a 1.356 rate of susceptibility of HBV-induced liver disease compared to the wild type GG genotype. The NCF4-rs1883112G allele occurred more frequently in healthy controls than in the CIB group in all three models (dominant, codominant, and recessive). Nox4-rs1836882 TC showed a protective association, being more frequent in healthy controls compared to the wild type TT genotype. GCLM-rs41303970A was associated with HBV-induced liver disease. The overall best model by multifactor dimensionality reduction was a five factor interaction model that had the highest cross validation consistency (10/10) and test accuracy (0.5669), P= 0.001. Oxidative stress-related gene polymorphisms are likely to be associated with HBV-induced liver disease, suggesting that information on these variations is useful for risk assessment of HBV-induced liver disease.

A Novel AKT Activator, SC79, Prevents Acute Hepatic Failure Induced by Fas-Mediated Apoptosis of Hepatocytes

Acute liver failure is a serious clinical problem of which the underlying pathogenesis remains unclear and for which effective therapies are lacking. The Fas receptor/ligand system, which is negatively regulated by AKT, is known to play a prominent role in hepatocytic cell death. We hypothesized that AKT activation may represent a strategy to alleviate Fas-induced fulminant liver failure. We report here that a novel AKT activator, SC79, protects hepatocytes from apoptosis induced by agonistic anti-Fas antibody CH11 (for humans) or Jo2 (for mice) and significantly prolongs the survival of mice given a lethal dose of Jo2. Under Fas-signaling stimulation, SC79 inhibited Fas aggregation, prevented the recruitment of the adaptor molecule Fas-associated death domain (FADD) and procaspase-8 [or FADD-like IL-1β-converting enzyme (FLICE)] into the death-inducing signaling complex (DISC), but SC79 enhanced the recruitment of the long and short isoforms of cellular FLICE-inhibitory protein at the DISC. All of the SC79-induced hepatoprotective and DISC-interruptive effects were confirmed to have been reversed by the Akt inhibitor LY294002. These results strongly indicate that SC79 protects hepatocytes from Fas-induced fatal hepatic apoptosis. The potent alleviation of Fas-mediated hepatotoxicity by the relatively safe drug SC79 highlights the potential of our findings for immediate hepatoprotective translation.

The palladacycle complex AJ-5 induces apoptotic cell death while reducing autophagic flux in rhabdomyosarcoma cells

Rhabdomyosarcoma (RMS) forms in skeletal muscle and is the most common soft tissue sarcoma in children and adolescents. Current treatment is associated with debilitating side effects and treatment outcomes for patients with metastatic disease are dismal. Recently, a novel binuclear palladacycle, AJ-5, was shown to exert potent cytotoxicity in melanoma and breast cancer and to present with negligible adverse effects in mice. This study investigates the anti-cancer activity of AJ-5 in alveolar and embryonal RMS. IC50 values of ≤ 0.2 µM were determined for AJ-5 and it displayed a favourable selectivity index of >2. Clonogenic and migration assays showed that AJ-5 inhibited the ability of RMS cells to survive and migrate, respectively. Western blotting revealed that AJ-5 induced levels of key DNA damage response proteins (γH2AX, p-ATM and p-Chk2) and the p38/MAPK stress pathway. This correlated with an upregulation of p21 and a G1 cell cycle arrest. Annexin V-FITC/propidium iodide staining revealed that AJ-5 induced apoptosis and necrosis. Apoptosis was confirmed by the detection of cleaved PARP and increased levels and activity of cleaved caspases-3, -7, -8 and -9. Furthermore, AJ-5 reduced autophagic flux as shown by reduced LC3II accumulation in the presence of bafilomycin A1 and a significant reduction in autophagosome flux J. Finally, pharmacokinetic studies in mice show that AJ-5 has a promising half-life and that its volume of distribution is high, its clearance low and its intraperitoneal absorption is good. Together these findings suggest that AJ-5 may be an effective chemotherapeutic with a desirable mechanism of action for treating drug-resistant and advanced sarcomas.

Oxidative stress, a trigger of hepatitis C and B virus-induced liver carcinogenesis

Virally induced liver cancer usually evolves over long periods of time in the context of a strongly oxidative microenvironment, characterized by chronic liver inflammation and regeneration processes. They ultimately lead to oncogenic mutations in many cellular signaling cascades that drive cell growth and proliferation. Oxidative stress, induced by hepatitis viruses, therefore is one of the factors that drives the neoplastic transformation process in the liver. This review summarizes current knowledge on oxidative stress and oxidative stress responses induced by human hepatitis B and C viruses. It focuses on the molecular mechanisms by which these viruses activate cellular enzymes/systems that generate or scavenge reactive oxygen species (ROS) and control cellular redox homeostasis. The impact of an altered cellular redox homeostasis on the initiation and establishment of chronic viral infection, as well as on the course and outcome of liver fibrosis and hepatocarcinogenesis will be discussed The review neither discusses reactive nitrogen species, although their metabolism is interferes with that of ROS, nor antioxidants as potential therapeutic remedies against viral infections, both subjects meriting an independent review.

Protective Effects of Moringa oleifera on HBV Genotypes C and H Transiently Transfected Huh7 Cells

Chronic hepatitis B infection treatment implicates a long-lasting treatment. M. oleifera extracts contain compounds with antiviral, antioxidant, and antifibrotic properties. In this study, the effect of M. oleifera was evaluated in Huh7 cells expressing either HBV genotypes C or H for the antiviral, antifibrotic, anti-inflammatory, and antioxidative responses. Huh7 cells were treated with an aqueous extract of M. oleifera (leaves) at doses of 0, 30, 45, or 60 μg/mL. The replicative virus and TGF-β1, CTGF, CAT, IFN-β1, and pgRNA expressions were measured by real time. HBsAg and IL-6 titers were determined by ELISA. CTGF, TGF-β1, IFN-β1, and pgRNA expressions decreased with M. oleifera treatment irrespective of the HBV genotype. HBsAg secretion in the supernatant of transfected Huh7 cells with both HBV genotypes was decreased regardless of the dose of M. oleifera. Similar effect was observed in proinflammatory cytokine IL-6, which had a tendency to decrease at 24 hours of treatment. Transfection with both HBV genotypes strongly decreased CAT expression, which is retrieved with M. oleifera treatment. M. oleifera treatment reduced fibrosis markers, IL-6, and HBsAg secretion in HBV genotypes C and H. However, at the level of replication, only HBV-DNA genotype C was slightly reduced with this treatment.

Inverse Association of Plasma Level of Glutathione Peroxidase with Liver Fibrosis in Chronic Hepatitis B: Potential Role of Iron

BACKGROUND

Oxidative stress has a major pathogenic role for liver damage following chronic hepatitis B. Glutathione peroxidase (Gpx) is necessary in oxidative state mechanism that is generally down-regulated by Hepatitis B virus (HBV) infection. On the other hand, disorders of iron homeostasis have been found out in HBV infected patients. Therefore, the objective of this study was to assess the interplay of Gpx and serum iron on clinical and virological features of patients with chronic HBV infection.

METHODS

One hundred and fifty adult, treatment-naïve, patients with chronic hepatitis B were randomly designated from an ongoing cohort of patients with HBV. Plasma Gpx1 concentration and HBV DNA quantity were measured. Liver stiffness was measured by transient elastography.

RESULTS

Serum iron had a positive association with HBV DNA count in the total population. Serum iron was not associated with liver stiffness. However, HBV DNA was significantly associated with liver stiffness only in male patients. Serum Gpx was inversely associated with liver stiffness. Serum iron and Gpx had indirect effects on liver stiffness via HBV DNA count. We observed dissimilar effects of serum iron on HBV DNA and Gpx on liver stiffness in male and female patients.

CONCLUSION

We identified interplay of serum iron and Gpx1 in relation to level of liver fibrosis in patients with chronic hepatitis B. Our results propose that oxidative stress and serum iron are differentially implicated in the progression of chronic hepatitis B in male and female patients.

Microsomal prostaglandin E synthase-1 protects against Fas-induced liver injury

Microsomal prostaglandin E synthase-1 (mPGES-1) is the terminal enzyme for the synthesis of prostaglandin E2 (PGE2), a proproliferative and antiapoptotic lipid molecule important for tissue regeneration and injury repair. In this study, we developed transgenic (Tg) mice with targeted expression of mPGES-1 in the liver to assess Fas-induced hepatocyte apoptosis and acute liver injury. Compared with wild-type (WT) mice, the mPGES-1 Tg mice showed less liver hemorrhage, lower serum alanine transaminase (ALT) and aspartate transaminase (AST) levels, less hepatic necrosis/apoptosis, and lower level of caspase cascade activation after intraperitoneal injection of the anti-Fas antibody Jo2. Western blotting analysis revealed increased expression and activation of the serine/threonine kinase Akt and associated antiapoptotic molecules in the liver tissues of Jo2-treated mPGES-1 Tg mice. Pretreatment with the mPGES-1 inhibitor (MF63) or the Akt inhibitor (Akt inhibitor V) restored the susceptibility of the mPGES-1 Tg mice to Fas-induced liver injury. Our findings provide novel evidence that mPGES-1 prevents Fas-induced liver injury through activation of Akt and related signaling and suggest that induction of mPGES-1 or treatment with PGE2 may represent important therapeutic strategy for the prevention and treatment of Fas-associated liver injuries.

Superoxide Dismutase 2 Genetic Variation as a Susceptibility Risk Factor for Alcoholic Cirrhosis

AIMS

Superoxide dismutase 2 (SOD2) is an important antioxidant phase 2 enzyme. The associations of SOD2 genetic variation and the risk of advanced alcoholic liver diseases are still debatable. We aimed to investigate the association of the main SOD2 genetic variant (47T>C) and the susceptibility to alcoholic cirrhosis.

METHODS

A total of 80 patients with alcoholic cirrhosis (AC), 80 patients with alcoholic non-cirrhosis (ANC), 80 with viral hepatitis B-related cirrhosis (VC), and 165 healthy controls (HC) were enrolled into this study. A polymerase chain reaction was used to genotype their SOD2 47T>C (rs4880).

RESULTS

There was no statistical difference in the frequency distribution of the three SOD2 47T>C genotypes among groups. However, if individuals with C variant were grouped together, the AC group had higher frequency of SOD2 C/C or C/T genotype than ANC, VC and HC groups had (38.7% vs. 21.3%, 26.3% and 21.8%, respectively, P = 0.010). After adjustment for confounders, the SOD2 C/C and C/T genotypes remained associated with the risk of AC (adjusted OR: 2.79 and 3.50, respectively, P < 0.03, compared with ANC and HC groups). In contrast, there was no significant difference of SOD2 genetic variation between VC and HC groups.

CONCLUSIONS

Anti-oxidative enzyme SOD2 47T>C genetic variant may increase the susceptibility to AC. This suggests that oxidative stress plays a role in the development of AC.

miR-150 Deficiency Protects against FAS-Induced Acute Liver Injury in Mice through Regulation of AKT

Although miR-150 is implicated in the regulation of immune cell differentiation and activation, it remains unknown whether miR-150 is involved in liver biology and disease. This study was performed to explore the potential role of miR-150 in LPS/D-GalN and Fas-induced liver injuries by using wild type and miR-150 knockout (KO) mice. Whereas knockout of miR-150 did not significantly alter LPS/D-GalN-induced animal death and liver injury, it protected against Fas-induced liver injury and mortality. The Jo2-induced increase in serum transaminases, apoptotic hepatocytes, PARP cleavage, as well as caspase-3/7, caspase-8, and caspase-9 activities were significantly attenuated in miR-150 KO mice. The liver tissues from Jo2-treated miR-150 KO mice expressed higher levels of Akt1, Akt2, total Akt, as well as p-Akt(Ser473) compared to the wild type livers. Pretreatment with the Akt inhibitor V reversed Jo2-induced liver injury in miR-150 KO mice. The primary hepatocytes isolated from miR-150 KO mice also showed protection against Fas-induced apoptosis in vitro (characterized by less prominent PARP cleavage, less nuclear fragmentation and less caspase activation) in comparison to hepatocytes from wild type mice. Luciferase reporter assays in hepatocytes transfected with the Akt1 or Akt2 3’-UTR reporter constructs (with or without mutation of miR-150 binding site) established Akt1 and Akt2 as direct targets of miR-150. Tail vein injection of lentiviral particles containing pre-miR-150 enhanced Jo2-induced liver injury in miR-150 KO mice. These findings demonstrate that miR-150 deficiency prevents Fas-induced hepatocyte apoptosis and liver injury through regulation of the Akt pathway.

Genetic and epigenetic alterations in hepatitis B virus-associated hepatocellular carcinoma

Hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC). Its chronic infection can lead to chronic liver inflammation and the accumulation of genetic alterations to result in the oncogenic transformation of hepatocytes. HBV can also sensitize hepatocytes to oncogenic transformation by causing genetic and epigenetic changes of the host chromosomes. HBV DNA can insert into host chromosomes and recent large-scale whole-genome sequencing studies revealed recurrent HBV DNA integrations sites that may play important roles in the initiation of hepatocellular carcinogenesis. HBV can also cause epigenetic changes by altering the methylation status of cellular DNA, the post-translational modification of histones, and the expression of microRNAs. These changes can also lead to the eventual hepatocellular transformation. These recent findings on the genetic and epigenetic alterations of the host chromosomes induced by HBV opened a new avenue for the development of novel diagnosis and treatments for HBV-induced HCC.

Dysplastic hepatocytes develop nuclear inclusions in a mouse model of viral hepatitis

Viral hepatitis resulting in chronic liver disease is an important clinical challenge and insight into the cellular processes that drive pathogenesis will be critical in order to develop new diagnostic and therapeutic options. Nuclear inclusions in viral and non-viral hepatitis are well documented and have diagnostic significance in some disease contexts. However, the origins and functional consequences of these nuclear inclusions remain elusive. To date the clinical observation of nuclear inclusions in viral and non-viral hepatitis has not been explored at depth in murine models of liver disease. Herein, we report that in a transgenic model of hepatitis B surface antigen mediated hepatitis, murine hepatocytes exhibit nuclear inclusions. Cells bearing nuclear inclusions were more likely to express markers of cell proliferation. We also established a correlation between these inclusions and oxidative stress. N-acetyl cysteine treatment effectively reduced oxidative stress levels, relieved endoplasmic reticulum (ER) stress, and the number of nuclear inclusions we observed in the transgenic mice. Our results suggest that the presence of nuclear inclusions in hepatocytes correlates with oxidative stress and cellular proliferation in a model of antigen mediated hepatitis.

Unraveling the complexity of hepatitis B virus: from molecular understanding to therapeutic strategy in 50 years

Hepatitis B virus (HBV) is a well-known hepadnavirus with a double-stranded circular DNA genome. Although HBV was first described approximately 50 years ago, the precise mechanisms of HBV infection and effective therapeutic strategies remain unclear. Here, we focus on summarizing the complicated mechanisms of HBV replication and infection, as well as genomic factors and epigenetic regulation. Additionally, we discuss in vivo models of HBV, as well as diagnosis, prevention and therapeutic drugs for HBV. Together, the data in this 50-year review may provide new clues to elucidate molecular mechanisms of HBV pathogenesis and shed new light on the future HBV therapies.

C1orf61 acts as a tumor activator in human hepatocellular carcinoma and is associated with tumorigenesis and metastasis

The genomic amplification of chromosome 1q long arm, the chromosomal region containing C1orf61, is a common event in human cancers. However, the expression pattern of chromosome 1 open reading frame 61 (C1orf61) in hepatocellular carcinoma (HCC) and its effects on HCC progression remain unclear. We have previously reported that C1orf61 is highly up-regulated during human embryogenesis. In this study, we report that C1orf61 expression is associated with the progression of liver disease. We found that C1orf61 is up-regulated in hepatic cirrhosis tissues and is further up-regulated in primary HCC tumors. Moreover, hepatitis B virus (HBV)-positive patients exhibited significantly higher levels of C1orf61 expression than HBV-negative patients. The evaluation of highly malignant HCC cell lines revealed high protein expression levels of C1orf61. Furthermore, the C1orf61 protein was found to be predominantly distributed within the cytoplasm. The ectopic expression of C1orf61 in the nonmalignant L02 cell line promoted cellular proliferation and colony formation in vitro, as well as cell cycle progression via the regulation of the expression of specific cell cycle-related proteins. In addition, the overexpression of C1orf61 in L02 cells facilitated cellular invasion and metastasis. The down-regulation of epithelial markers (E-cadherin and occludin) and the up-regulation of mesenchymal markers (N-cadherin, vimentin, and snail) suggested that the overexpression of C1orf61 induced the epithelial-mesenchymal transition (EMT) that is linked to metastasis. Taken together, our findings demonstrate, for the first time, the roles of C1orf61 in HCC tumorigenesis and metastasis.