HBx-Induced Hepatic Steatosis and Apoptosis Are Regulated by TNFR1- and NF-κB-Dependent Pathways

Current therapeutic modalities and chemopreventive role of natural products in liver cancer: Progress and promise

Liver cancer is a severe concern for public health officials since the clinical cases are increasing each year, with an estimated 5-year survival rate of 30%–35% after diagnosis. Hepatocellular carcinoma (HCC) constitutes a significant subtype of liver cancer (approximate75%) and is considered primary liver cancer. Treatment for liver cancer mainly depends on the stage of its progression, where surgery including, hepatectomy and liver transplantation, and ablation and radiotherapy are the prime choice. For advanced liver cancer, various drugs and immunotherapy are used as first-line treatment, whereas second-line treatment includes chemotherapeutic drugs from natural and synthetic origins. Sorafenib and lenvatinib are first-line therapies, while regorafenib and ramucirumab are second-line therapy. Various metabolic and signaling pathways such as Notch, JAK/ STAT, Hippo, TGF-β, and Wnt have played a critical role during HCC progression. Dysbiosis has also been implicated in liver cancer. Drug-induced toxicity is a key obstacle in the treatment of liver cancer, necessitating the development of effective and safe medications, with natural compounds such as resveratrol, curcumin, diallyl sulfide, and others emerging as promising anticancer agents. This review highlights the current status of liver cancer research, signaling pathways, therapeutic targets, current treatment strategies and the chemopreventive role of various natural products in managing liver cancer.

Hepatitis B virus infection combined with nonalcoholic fatty liver disease: Interaction and prognosis

Hepatitis B virus (HBV) infection is still one kind of the infectious diseases that seriously threaten human health. Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide. HBV infection complicated with NAFLD is increasingly common. This review mainly describes the interaction between HBV infection and NAFLD, the interaction between steatosis and antiviral drugs, and the prognosis of HBV infection complicated with NAFLD. Most studies suggest that HBV infection may reduce the incidence of NAFLD. NAFLD can promote the spontaneous clearance of hepatitis B surface antigen (HBsAg), but whether it affects antiviral efficacy has been reported inconsistently. HBV infection combined with NAFLD can promote the progression of liver fibrosis, especially in patients with severe steatosis. The outcome of HBV infection combined with NAFLD predisposing to the progression of HCC remains controversial.

NAFLD and HBV interplay - related mechanisms underlying liver disease progression

Non-alcoholic fatty liver disease (NAFLD) and Hepatitis B virus infection (HBV) constitute common chronic liver diseases with worldwide distribution. NAFLD burden is expected to grow in the coming decade, especially in western countries, considering the increased incidence of diabetes and obesity. Despite the organized HBV vaccinations and use of anti-viral therapies globally, HBV infection remains endemic and challenging public health issue. As both NAFLD and HBV have been associated with the development of progressive fibrosis, cirrhosis and hepatocellular carcinoma (HCC), the co-occurrence of both diseases has gained great research and clinical interest. The causative relationship between NAFLD and HBV infection has not been elucidated so far. Dysregulated fatty acid metabolism and lipotoxicity in NAFLD disease seems to initiate activation of signaling pathways that enhance pro-inflammatory responses and disrupt hepatocyte cell homeostasis, promoting progression of NAFLD disease to NASH, fibrosis and HCC and can affect HBV replication and immune encountering of HBV virus, which may further have impact on liver disease progression. Chronic HBV infection is suggested to have an influence on metabolic changes, which could lead to NAFLD development and the HBV-induced inflammatory responses and molecular pathways may constitute an aggravating factor in hepatic steatosis development. The observed altered immune homeostasis in both HBV infection and NAFLD could be associated with progression to HCC development. Elucidation of the possible mechanisms beyond HBV chronic infection and NAFLD diseases, which could lead to advanced liver disease or increase the risk for severe complications, in the case of HBV-NAFLD co-existence is of high clinical significance in the context of designing effective therapeutic targets.

Interplay between Lipid Metabolism, Lipid Droplets, and DNA Virus Infections

Lipid droplets (LDs) are cellular organelles rich in neutral lipids such as triglycerides and cholesterol esters that are coated by a phospholipid monolayer and associated proteins. LDs are known to play important roles in the storage and availability of lipids in the cell and to serve as a source of energy reserve for the cell. However, these structures have also been related to oxidative stress, reticular stress responses, and reduced antigen presentation to T cells. Importantly, LDs are also known to modulate viral infection by participating in virus replication and assembly. Here, we review and discuss the interplay between neutral lipid metabolism and LDs in the replication cycle of different DNA viruses, identifying potentially new molecular targets for the treatment of viral infections.

Hepatitis B virus X protein promotes epithelial-mesenchymal transition of hepatocellular carcinoma cells by regulating SOCS1

Hepatocellular carcinoma (HCC), a primary type of liver cancer, is one of the leading causes of cancer related deaths worldwide. HCC patients have poor prognosis due to intrahepatic and extrahepatic metastasis. Hepatitis B virus (HBV) infection is one of the major causes of various liver diseases including HCC. Among HBV gene products, HBV X protein (HBx) plays an important role in the development and metastasis of HCC. However, the mechanism of HCC metastasis induced by HBx has not been elucidated yet. In this study, for the first time, we report that HBx interacts with the suppressor of cytokine signaling 1 (SOCS1) which negatively controls NF-κB by degrading p65, a subunit of NF-κB. NF-κB activates the transcription of factors associated with epithelial-mesenchymal transition (EMT), a crucial cellular process associated with invasiveness and migration of cancer cells. Here, we report that HBx physically binds to SOCS1, subsequently prevents the ubiquitination of p65, activates the transcription of EMT transcription factors and enhance cell migration and invasiveness, suggesting a new mechanism of HBV-associated HCC metastasis.

Hepatitis B virus X protein promotes epithelial-mesenchymal transition of hepatocellular carcinoma cells by regulating SOCS1

Hepatocellular carcinoma (HCC), a primary type of liver cancer, is one of the leading causes of cancer related deaths worldwide. HCC patients have poor prognosis due to intrahepatic and extrahepatic metastasis. Hepatitis B virus (HBV) infection is one of the major causes of various liver diseases including HCC. Among HBV gene products, HBV X protein (HBx) plays an important role in the development and metastasis of HCC. However, the mechanism of HCC metastasis induced by HBx has not been elucidated yet. In this study, for the first time, we report that HBx interacts with the suppressor of cytokine signaling 1 (SOCS1) which negatively controls NF-κB by degrading p65, a subunit of NF-κB. NF-κB activates the transcription of factors associated with epithelial-mesenchymal transition (EMT), a crucial cellular process associated with invasiveness and migration of cancer cells. Here, we report that HBx physically binds to SOCS1, subsequently prevents the ubiquitination of p65, activates the transcription of EMT transcription factors and enhance cell migration and invasiveness, suggesting a new mechanism of HBV-associated HCC metastasis. [BMB Reports 2022; 55(5): 220-225].

Hepatitis B x antigen (HBx) is an important therapeutic target in the pathogenesis of hepatocellular carcinoma

Hepatitis B virus (HBV) is a human pathogen that has infected an estimated two billion people worldwide. Despite the availability of highly efficacious vaccines, universal screening of the blood supply for virus, and potent direct acting anti-viral drugs, there are more than 250 million carriers of HBV who are at risk for the sequential development of hepatitis, fibrosis, cirrhosis and hepatocellular carcinoma (HCC). More than 800,000 deaths per year are attributed to chronic hepatitis B. Many different therapeutic approaches have been developed to block virus replication, and although effective, none are curative. These treatments have little or no impact upon the portions of integrated HBV DNA, which often encode the virus regulatory protein, HBx. Although given little attention, HBx is an important therapeutic target because it contributes importantly to (a) HBV replication, (b) in protecting infected cells from immune mediated destruction during chronic infection, and (c) in the development of HCC. Thus, the development of therapies targeting HBx, combined with other established therapies, will provide a functional cure that will target virus replication and further reduce or eliminate both the morbidity and mortality associated with chronic liver disease and HCC. Simultaneous targeting of all these characteristics underscores the importance of developing therapies against HBx.

The Hepatitis B Virus Interactome: A Comprehensive Overview

Despite the availability of a prophylactic vaccine, chronic hepatitis B (CHB) caused by the hepatitis B virus (HBV) is a major health problem affecting an estimated 292 million people globally. Current therapeutic goals are to achieve functional cure characterized by HBsAg seroclearance and the absence of HBV-DNA after treatment cessation. However, at present, functional cure is thought to be complicated due to the presence of covalently closed circular DNA (cccDNA) and integrated HBV-DNA. Even if the episomal cccDNA is silenced or eliminated, it remains unclear how important the high level of HBsAg that is expressed from integrated HBV DNA is for the pathology. To identify therapies that could bring about high rates of functional cure, in-depth knowledge of the virus' biology is imperative to pinpoint mechanisms for novel therapeutic targets. The viral proteins and the episomal cccDNA are considered integral for the control and maintenance of the HBV life cycle and through direct interaction with the host proteome they help create the most optimal environment for the virus whilst avoiding immune detection. New HBV-host protein interactions are continuously being identified. Unfortunately, a compendium of the most recent information is lacking and an interactome is unavailable. This article provides a comprehensive review of the virus-host relationship from viral entry to release, as well as an interactome of cccDNA, HBc, and HBx.

Metabolic dysfunction-associated fatty liver disease increases risk of adverse outcomes in patients with chronic hepatitis B

Background & Aims

A recent consensus document has defined metabolic dysfunction-associated fatty liver disease (MAFLD) as hepatic steatosis together with overweight, diabetes, and/or a combination of other metabolic risk factors. The clinical relevance of this novel diagnosis is unknown among patients with chronic hepatitis B (CHB). We studied the association between MAFLD (with or without steatohepatitis) and adverse clinical outcomes in patients with CHB.

Methods

We performed a retrospective long-term follow-up cohort study at 2 tertiary hospitals in patients with CHB who underwent liver biopsy. Biopsies were reassessed for steatosis, degree of fibrosis, and presence of steatohepatitis. Associations with event-free hepatocellular carcinoma (HCC)-free and transplant-free survival were explored.

Results

In our cohort, 1076 patients were included, median follow-up was 9.8 years (25th-75th percentile: 6.6-14.0), and 107 events occurred in 78 patients, comprising death (n = 43), HCC (n = 36), liver decompensation (n = 21), and/or liver transplantation (n = 7). MAFLD was present in 296 (27.5%) patients and was associated with reduced event-free (adjusted hazard ratio [aHR] 2.00, 95% CI 1.26-3.19), HCC-free (aHR 1.93, 95% CI 1.17-3.21), and transplant-free survival (aHR 1.80, 95% CI 0.98-3.29) in multivariable analysis. Among patients with MAFLD, the presence of steatohepatitis (p = 0.95, log-rank test) was not associated with adverse outcomes.

Conclusions

The presence of MAFLD in patients with CHB was associated with an increased risk for liver-related clinical events and death. Among patients with MAFLD, steatohepatitis did not increase the risk of adverse outcomes. Our findings highlight the importance of metabolic dysfunction in patients with CHB.

Lay summary

Recently, metabolic dysfunction-associated fatty liver disease (MAFLD) has been defined as fatty liver disease with signs of metabolic dysfunction. Among patients with chronic hepatitis B, MAFLD was associated with liver-related events and death. Metabolic health assessment should be encouraged among patients with chronic hepatitis B, especially in those with fatty liver disease.

Comparing hepatic steatosis distribution patterns between non-alcoholic fatty liver disease and fatty liver disease with chronic hepatitis B by second-harmonic generation/two-photon excited fluorescence method

INTRODUCTION AND OBJECTIVES

Hepatitis B virus (HBV) might be an etiological factor modulating fat distribution in steatotic livers. We aim to compare hepatic steatosis distribution patterns between NAFLD and FL&CHB patients with second-harmonic generation (SHG)/two-photon excited fluorescence (TPEF) method.

PATIENTS AND METHODS

42 patients with NAFLD, 46 with FL&CHB and 55 without steatosis were enrolled in the study. Overall and regional steatosis in liver sections were quantified by SHG/TPEF method. The accuracy of which was validated by pathologist evaluation and magnetic resonance spectroscopy (MRS). Difference in degree of overall and regional steatosis between NAFLD and FL&CHB groups was analyzed by Mann-Whitney U test. Multivariable linear regression analysis was used to model factors contributing to steatosis distribution.

RESULTS

The hepatic steatosis measured by SHG/TPEF method was highly correlated with pathologist grading (r=0.83, p<0.001) and MRS measurement (r=0.82, p<0.001). The level of overall steatosis in FL&CHB group is significantly lower than that in NAFLD group (p<0.001). In NAFLD group, periportal region has significantly lower steatosis percentage than lobule region and overall region (p<0.001); while in FL&CHB group there is no difference among regions. The ratio of steatosis at periportal region to lobule region is significantly higher in FL&CHB group than that in NAFLD group (p<0.05). Multivariable linear regression analysis shows that HBV infection is the major contributing factor (β=0.322, p<0.01).

CONCLUSIONS

SHG/TPEF method is an accurate and objective method in hepatic steatosis quantification. By quantifying steatosis in different histological regions, we found steatosis distribution patterns are different between FL&CHB and NAFLD patients.

NFKB1-mediated downregulation of microRNA-106a promotes oxidative stress injury and insulin resistance in mice with gestational hypertension

This study intended to investigate the role of NFKB1 in oxidative stress injury and insulin resistance in gestational hypertension (GH) mice. Following establishment of a GH mouse model by high-fat diet, NFKB1, miR-106a, and FLOT2 expression was detected in liver of mice. After NFKB1, miR-106a, and FLOT2 were altered in GH mice by lentiviral vector, oxidative stress markers in liver tissues were examined by colorimetry, and insulin resistance was assessed by fasting blood glucose and fasting insulin levels. Next, hepatocytes were isolated from GH mice and treated with miR-106a mimic, inhibitor or siRNA, followed by determination of hepatocyte apoptosis and the expression of inflammation- and apoptosis-related factors. Evaluation of the correlations among NFKB1, miR-106a, and FLOT2 were conducted. Liver of GH mice harbored NFKB1 and FLOT2 upregulation and miR-106a downregulation. miR-106a was transcriptionally inhibited by NFKB1, and negatively targeted FLOT2. Oxidative stress injury and insulin resistance in GH mice and apoptosis and inflammation of hepatocytes from GH mice were decreased after silencing NFKB1 or FLOT2 or overexpressing miR-106a. These findings provided evidence demonstrating the inhibitory effect of NFKB1 silencing on oxidative stress injury and insulin resistance in GH mice via miR-106a upregulation and FLOT2 downregulation.

Giardia duodenalis induces extrinsic pathway of apoptosis in intestinal epithelial cells through activation of TNFR1 and K63 de-ubiquitination of RIP1 in vitro

Giardia duodenalis is one of main causative agents of diarrhea that affects the health of millions of people on a global scale per year. It has been clear that attachment of G. duodenalis trophozoites to intestinal epithelium cells (IECs) can induce cell death, while the underlying cellular and molecular mechanisms remain to be explored. It was shown in this study that treatment of Caco-2 cells with Giardia trophozoites could result in reduced cell viability. RNA sequencing analysis demonstrated that expressions of many apoptosis-related genes and some deubiquitinase genes displayed marked changes in trophozoite-treated cells. Trophozoites activated the death-signaling receptor TNFR1 on the IEC surface and caspase-3/8 (CASP3/8) signaling pathways in Caco-2 cells. K63 ubiquitination level of RIP1 was reduced upon stimulation with trophozoites, in parallel, the expressions of deubiquitinases CYLD and A20 were increased. The caspase inhibitor Q-VD-OPH could rescue trophozoite-induced cell apoptosis. Likewise, TNFR1, CYLD, and A20 silencing decreased the levels of cleaved CASP3/8 in trophozoite-treated cells and reversed the pro-apoptosis induction effect of trophozoites. These data suggest that Giardia trophozoite stimulation can activate CASP3/8 signaling pathways via activation of TNFR1 and K63 de-ubiquitination of RIP1 caused by up-regulated expressions of CYLD and A20, and promote Caco-2 cell apoptosis. The present study deepens our understanding of the mechanism of interaction between Giardia and IECs.

Serum anti-EIF3A autoantibody as a potential diagnostic marker for hepatocellular carcinoma

Tumor-associated autoantibodies are promising diagnostic biomarkers for early detection of tumors. We have screened a novel tumor-associated autoantibody in hepatocellular carcinoma (HCC) model mice. Its target antigen was identified as eukaryotic translation initiation factor 3 subunit A (EIF3A) by proteomic analysis, and the elevated expression of EIF3A in HCC tissues of tumor model mice as well as human patients was shown. Also, its existence in tumor-derived exosomes was revealed, which seem to be the cause of tumor-associated autoantibody production. To use serum anti-EIF3A autoantibody as biomarker, ELISA detecting anti-EIF3A autoantibody in human serum was performed using autoantibody-specific epitope. For the sensitive detection of serum autoantibodies its specific conformational epitopes were screened from the random cyclic peptide library, and a streptavidin antigen displaying anti-EIF3A autoantibody-specific epitope, XC90p2(-CPVRSGFPC-), was used as capture antigen. It distinguished patients with HCC (n = 102) from healthy controls (n = 0285) with a sensitivity of 79.4% and specificity of 83.5% (AUC = 0.87). Also, by simultaneously detecting with other HCC biomarkers, including alpha-fetoprotein, HCC diagnostic sensitivity improved from 79.4% to 85%. Collectively, we suggest that serum anti-EIF3A autoantibody is a useful biomarker for the diagnosis of HCC and the combinational detection of related biomarkers can enhance the accuracy of the cancer diagnosis.

Protective effect of dihydromyricetin revents fatty liver through nuclear factor‑κB/p53/B‑cell lymphoma 2‑associated X protein signaling pathways in a rat model

Dihydromyricetin is the major flavonoid in vine tea, whose pharmacological action has attracted increasing attention in recent years. The triglyceride, albumin (ALB), alanine aminotransferase, aspartate aminotransferase, malondialdehyde, superoxide dismutase, glutathione (GSH), GSH peroxidase, tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and IL-18 expression levels were measured using enzyme-linked immunosorbent assay kits. The protein levels of ALB and collagen I, PPARα, NF-κB, p53 and Bax were used to measure using western blotting. The results revealed that dihydromyricetin prevented the development of fatty liver, and inhibited oxidative stress, inflammation and apoptosis in a fatty liver rat model. In addition, treatment with dihydromyricetin inhibited the levels of ALB and collagen I, while it induced peroxisome proliferator-activated receptor α protein expression. Dihydromyricetin also suppressed the protein expression levels of nuclear factor (NF)-κB, p53 and B-cell lymphoma 2-associated X protein (Bax) in the rat model. Collectively, it is concluded that dihydromyricetin exerted a protective effect on fatty liver through NF-κB/p53/Bax signaling pathways in a rat model.

A systematic review of the present and future of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the Western world. Ongoing research has furthered our understanding of NAFLD, the nature of progression of this disease, and its impact on morbidity and mortality. An active form of NAFLD is non-alcoholic steatohepatitis (NASH); it is the most severe subtype, without any current recommended therapies, according to the European Medicines Agency. The development of new therapies presents challenges, notably due to the slow progression of NASH and the clinically relevant endpoints.

Correlating new data with effective treatment regimens is an emerging challenge, which will increase our understanding of the factors affecting the NAFLD course. This can enable more appropriate non-invasive prognostic assessments, which can focus on specifically at-risk NAFLD populations for tailored individual treatment. This review article aims to highlight the current developments in the field of NAFLD: pathogenesis, epidemiology, diagnosis, clinical features, and available treatment, including novel targets and therapies.

Identification of anti-SF3B1 autoantibody as a diagnostic marker in patients with hepatocellular carcinoma

BACKGROUND

Tumor-associated (TA) autoantibodies, which are generated by the immune system upon the recognition of abnormal TA antigens, are promising biomarkers for the early detection of tumors. In order to detect autoantibody biomarkers effectively, antibody-specific epitopes in the diagnostic test should maintain the specific conformations that are as close as possible to those presenting in the body. However, when using patients' serum as a source of TA autoantibodies the characterization of the autoantibody-specific epitope is not easy due to the limited amount of patient-derived serum.

METHODS

To overcome these limits, we constructed a B cell hybridoma pool derived from a hepatocellular carcinoma (HCC) model HBx-transgenic mouse and characterized autoantibodies derived from them as tumor biomarkers. Their target antigens were identified by mass spectrometry and the correlations with HCC were examined. With the assumption that TA autoantibodies generated in the tumor mouse model are induced in human cancer patients, the enzyme-linked immunosorbent assays (ELISA) based on the characteristics of mouse TA autoantibodies were developed for the detection of autoantibody biomarkers in human serum. To mimic natural antigenic structures, the specific epitopes against autoantibodies were screened from the phage display cyclic random heptapeptide library, and the streptavidin antigens fused with the specific epitopes were used as coating antigens.

RESULTS

In this study, one of HCC-associated autoantibodies derived from HBx-transgenic mouse, XC24, was characterized. Its target antigen was identified as splicing factor 3b subunit 1 (SF3B1) and the high expression of SF3B1 was confirmed in HCC tissues. The specific peptide epitopes against XC24 were selected and, among them, XC24p11 cyclic peptide (-CDATPPRLC-) was used as an epitope of anti-SF3B1 autoantibody ELISA. With this epitope, we could effectively distinguish between serum samples from HCC patients (n = 102) and healthy subjects (n = 85) with 73.53% sensitivity and 91.76% specificity (AUC = 0.8731). Moreover, the simultaneous detection of anti-XC24p11 epitope autoantibody and AFP enhanced the efficiency of HCC diagnosis with 87.25% sensitivity and 90.59% specificity (AUC = 0.9081).

CONCLUSIONS

ELISA using XC24p11 peptide epitope that reacts against anti-SF3B1 autoantibody can be used as a novel test to enhance the diagnostic efficiency of HCC.

Interferon-α inhibits cell migration and invasion and induces the expression of antiviral proteins in Huh-7 cells transfected with hepatitis B virus X gene-expressing lentivirus

Hepatitis B virus (HBV) X protein (HBx) serves an important role in HBV infection and the development of HBV-related liver cancer. Interferon-α (IFN-α) is used to treat patients with HBV; however, the role of IFN-α in the development of HBV-related liver cancer remains unclear. The present study established a new HBV-related liver cancer model (Huh-7-HBx) by transfecting the hepatoma cell line Huh-7, with HBx-expressing lentivirus. Following IFN-α treatment, cell viability, migration and invasion, as well as the expression of antiviral proteins in Huh-7-HBx, were subsequently determined. The results demonstrated that HBx-expressing lentivirus had no significant effect on cell viability but promoted the migration and invasion of Huh-7 cells. The expression of the antiviral genes IFN α and β receptor subunit 1 (IFNAR1), IFNAR2, IFN-stimulated gene factor 3, double-stranded RNA-activated protein kinase and ribonuclease L, was also increased. Following treatment of Huh-7-HBx cells with IFN-α, the expression of antiviral genes was increased at the level of transcription and translation, whereas cell migration and invasion was decreased. The present study suggests that IFN-α may attenuate the development of HBV-related liver cancer by reducing cell migration and invasion and promoting the expression of antiviral proteins.

Non-alcoholic fatty liver disease: An expanded review

Non-alcoholic fatty liver disease (NAFLD) encompasses the simple steatosis to more progressive steatosis with associated hepatitis, fibrosis, cirrhosis, and in some cases hepatocellular carcinoma. NAFLD is a growing epidemic, not only in the United States, but worldwide in part due to obesity and insulin resistance leading to liver accumulation of triglycerides and free fatty acids. Numerous risk factors for the development of NAFLD have been espoused with most having some form of metabolic derangement or insulin resistance at the core of its pathophysiology. NAFLD patients are at increased risk of liver-related as well as cardiovascular mortality, and NAFLD is rapidly becoming the leading indication for liver transplantation. Liver biopsy remains the gold standard for definitive diagnosis, but the development of noninvasive advanced imaging, biochemical and genetic tests will no doubt provide future clinicians with a great deal of information and opportunity for enhanced understanding of the pathogenesis and targeted treatment. As it currently stands several medications/supplements are being used in the treatment of NAFLD; however, none seem to be the "magic bullet" in curtailing this growing problem yet. In this review we summarized the current knowledge of NAFLD epidemiology, risk factors, diagnosis, pathogenesis, pathologic changes, natural history, and treatment in order to aid in further understanding this disease and better managing NAFLD patients.

Differentially expressed genes and gene networks involved in pig ovarian follicular atresia

Ovarian folliculogenesis corresponds to the development of follicles leading to either ovulation or degeneration, this latter process being called atresia. Even if atresia involves apoptosis, its mechanism is not well understood. The objective of this study was to analyze global gene expression in pig granulosa cells of ovarian follicles during atresia. The transcriptome analysis was performed on a 9,216 cDNA microarray to identify gene networks and candidate genes involved in pig ovarian follicular atresia. We found 1,684 significantly regulated genes to be differentially regulated between small healthy follicles and small atretic follicles. Among them, 287 genes had a fold-change higher than two between the two follicle groups. Eleven genes ( DKK3, GADD45A, CAMTA2, CCDC80, DAPK2, ECSIT, MSMB, NUPR1, RUNX2, SAMD4A, and ZNF628) having a fold-change higher than five between groups could likely serve as markers of follicular atresia. Moreover, automatic confrontation of deregulated genes with literature data highlighted 93 genes as regulatory candidates of pig granulosa cell atresia. Among these genes known to be inhibitors of apoptosis, stimulators of apoptosis, or tumor suppressors INHBB, HNF4, CLU, different interleukins ( IL5, IL24), TNF-associated receptor ( TNFR1), and cytochrome-c oxidase ( COX) were suggested as playing an important role in porcine atresia. The present study also enlists key upstream regulators in follicle atresia based on our results and on a literature review. The novel gene candidates and gene networks identified in the current study lead to a better understanding of the molecular regulation of ovarian follicular atresia.

HBx regulates fatty acid oxidation to promote hepatocellular carcinoma survival during metabolic stress

Due to a high rate of nutrient consumption and inadequate vascularization, hepatocellular carcinoma (HCC) cells constantly undergo metabolic stress during tumor development. Hepatitis B virus (HBV) X protein (HBx) has been implicated in the pathogenesis of HBV-induced HCC. In this study, we investigated the functional roles of HBx in HCC adaptation to metabolic stress. Up-regulation of HBx increased the intracellular ATP and NADPH generation, and induced the resistance to glucose deprivation, whereas depletion of HBx via siRNA abolished these effects and conferred HCC cells sensitive to glucose restriction. Though HBx did not affect the glycolysis and oxidative phosphorylation capacity of HCC cells under normal culture conditions, it facilitated fatty acid oxidation (FAO) in the absence of glucose, which maintained NADPH and ATP levels. Further investigation showed that HBx expression, under glucose deprivation, stimulated phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) via a calcium/CaMKK-dependent pathway, which was required for the activation of FAO. Conversely, inhibition of FAO by etomoxir (ETO) restored the sensitivity of HBx-expressing cells to glucose deficiency in vitro and retarded xenograft tumor formation in vivo. Finally, HBx-induced activation of the AMPK and FAO pathways were also observed in xenograft tumors and HBV-associated HCC specimens. Our data suggest that HBx plays a key role in the maintenance of redox and energy homeostasis by activating FAO, which is critical for HCC cell survival under conditions of metabolic stress and might be exploited for therapeutic benefit.

The embryonic stress response to in vitro culture: insight from genomic analysis

Recent genomic studies have shed light on the impact of in vitro culture (IVC) on embryonic homeostasis and the differential gene expression profiles associated with lower developmental competence. Consistently, the embryonic stress responses to IVC conditions correlate with transcriptomic changes in pathways related to energetic metabolism, extracellular matrix remodelling and inflammatory signalling. These changes appear to result from a developmental adaptation that enhances a Warburg-like effect known to occur naturally during blastulation. First discovered in cancer cells, the Warburg effect (increased glycolysis under aerobic conditions) is thought to result from mitochondrial dysfunction. In the case of IVC embryos, culture conditions may interfere with mitochondrial maturation and oxidative phosphorylation, forcing cells to rely on glycolysis in order to maintain energetic homeostasis. While beneficial in the short term, such adaptations may lead to epigenetic changes with potential long-term effects on implantation, foetal growth and post-natal health. We conclude that lessening the detrimental effects of IVC on mitochondrial activity would lead to significantly improved embryo quality.

X region mutations of hepatitis B virus related to clinical severity

Chronic hepatitis B virus (HBV) infection remains a major health problem, with more than 240 million people chronically infected worldwide and potentially 650000 deaths per year due to advanced liver diseases including liver cirrhosis and hepatocellular carcinoma (HCC). HBV-X protein (HBx) contributes to the biology and pathogenesis of HBV via stimulating virus replication or altering host gene expression related to HCC. The HBV X region contains only 465 bp encoding the 16.5 kDa HBx protein, which also contains several critical cis-elements such as enhancer II, the core promoter and the microRNA-binding region. Thus, mutations in this region may affect not only the HBx open reading frame but also the overlapped cis-elements. Recently, several types of HBx mutations significantly associated with clinical severity have been described, although the functional mechanism in most of these cases remains unsolved. This review article will mainly focus on the HBx mutations proven to be significantly related to clinical severity via epidemiological studies.

Cooperative effects of hepatitis B virus and TNF may play important roles in the activation of metabolic pathways through the activation of NF-κB

Elevated levels of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β are often observed in the sera of hepatitis B virus (HBV)-infected patients. It is well known that these cytokines activate nuclear factor-κB (NF-κB)-signaling, and are associated with endoplasmic reticulum (ER) stress. We investigated whether HBV or HBV X protein (HBx) enhanced the activation of NF-κB in the presence of TNF and/or IL-1β, and their effects on the expression of metabolic pathway-associated genes. We examined whether HBV or HBx enhanced cytokine-induced activation of NF-κB in hepatocytes, using a reporter assay, in the presence or absence of TNF and/or IL-1β. The expression of insulin-like growth factor binding protein 1 (IGFBP1), one of the NF-κB target genes was also examined. The expression of metabolic pathway-associated genes in HepG2 and HepG2.2.15 cells in the presence or absence of TNF was evaluated by RT-qPCR. Human hepatocytes expressed TNF receptors and IL-1 receptors. NF-κB was activated by cooperation between HBx and TNF in human hepatocytes. We observed IGFBP1 expression in HBV infection and that a number of metabolic pathway-associated genes were upregulated in HepG2.2.15 cells, compared with HepG2 cells with or without TNF treatment. We observed the cooperative effects of HBV and TNF which enhanced the activation of NF-κB as well as upregulated the expression of metabolic pathway-associated genes in hepatocytes. These effects may be important in the development of HBV-associated metabolic syndrome.

Nonalcoholic fatty liver disease and hepatic cirrhosis: Comparison with viral hepatitis-associated steatosis

Nonalcoholic fatty liver disease (NAFLD) including nonalcoholic steatohepatitis (NASH) is globally increasing and has become a world-wide health problem. Chronic infection with hepatitis B virus or hepatitis C virus (HCV) is associated with hepatic steatosis. Viral hepatitis-associated hepatic steatosis is often caused by metabolic syndrome including obesity, type 2 diabetes mellitus and/or dyslipidemia. It has been reported that HCV genotype 3 exerts direct metabolic effects that lead to hepatic steatosis. In this review, the differences between NAFLD/NASH and viral hepatitis-associated steatosis are discussed.

Interactions of Hepatitis B Virus Infection with Nonalcoholic Fatty Liver Disease: Possible Mechanisms and Clinical Impact

Hepatitis B virus (HBV) infection is a major etiology of chronic liver disease worldwide. In the past decade, nonalcoholic fatty liver disease (NAFLD) has emerged as a common liver disorder in general population. Accordingly, the patient number of chronic hepatitis B (CHB) concomitant with NAFLD grows rapidly. The present article reviewed the recent studies aiming to explore the relationship between CHB and NAFLD from different aspects, including the relevant pathogenesis of CHB and NAFLD, the intracellular molecular mechanisms overlaying HBV infection and hepatic steatosis, and the observational studies with animal models and clinical cohorts for analyzing the coincidence of the two diseases. It is concluded that although numerous cross-links have been suggested between the molecular pathways in HBV infection and NAFLD pathogenesis, regarding whether HBV infection can substantially interfere with the occurrence of NAFLD or vice versa in the patients, there is still far from a conclusive agreement.

Valproate-induced liver injury: modulation by the omega-3 fatty acid DHA proposes a novel anticonvulsant regimen

Background

The polyunsaturated, ω-3 fatty acid, docosahexaenoic acid (DHA), claims diverse cytoprotective potentials, although via largely undefined triggers. Thus, we currently first tested the ability of DHA to ameliorate valproate (VPA)-evoked hepatotoxicity, to modulate its anticonvulsant effects, then sought the cellular and molecular basis of such actions. Lastly, we also verified whether DHA may kinetically alter plasma levels/clearance rate of VPA.

Methods and Results

VPA (500 mg/kg orally for 14 days in rats) evoked prominent hepatotoxicity that appeared as a marked rise (2- to 4-fold) in serum hepatic enzymes (γ-glutamyl transferase [γ-GT], alanine aminotransferase [ALT], and alkaline phosphatase [ALP]), increased hepatic lipid peroxide (LPO) and tumor necrosis factor-alpha (TNFα) levels, as well as myeloperoxidase (MPO) activity (3- to 5-fold), lowering of serum albumin (40 %), and depletion of liver reduced-glutathione (GSH, 35 %). Likewise, histopathologic examination revealed hepatocellular degeneration, replacement by inflammatory cells, focal pericentral necrosis, and micro/macrovesicular steatosis. Concurrent treatment with DHA (250 mg/kg) markedly blunted the elevated levels of liver enzymes, lipid peroxides, TNFα, and MPO activity, while raising serum albumin and hepatic GSH levels. DHA also alleviated most of the cytologic insults linked to VPA. Besides, in a pentylenetetrazole (PTZ) mouse convulsion model, DHA (250 mg/kg) markedly increased the latency in convulsion evoked by VPA, beyond their individual responses. Lastly, pharmacokinetic studies revealed that joint DHA administration did not alter serum VPA concentrations.

Conclusions

DHA substantially ameliorated liver injury induced by VPA, while also markedly boosted its pharmacologic effects. DHA manipulated definite cellular machinery to curb liver oxidative stress and inflammation, without affecting VPA plasma levels. Collectively, these protective and synergy profiles for DHA propose a superior VPA-drug combination regimen.

Prevalence of steatosis and insulin resistance in patients with chronic hepatitis B compared with chronic hepatitis C and non-alcoholic fatty liver disease

The association of NAFLD with chronic hepatitis C (CHC) has been extensively studied but little is known about its coexistence with chronic hepatitis B (CHB).

AIMS

To investigate the prevalence and determinants of steatosis and insulin resistance (IR) in CHB and its consequences on liver injury compared with CHC and NAFLD.

METHODS

Patients with CHB (N=110), CHC (N=111) and NAFLD (N=136) were evaluated by biomarkers of steatosis (SteatoTest>0.38 as a surrogate for steatosis >5%), IR (HOMA-IR>2.7 as a surrogate for IR) and fibrosis (FibroTest>0.48 as a surrogate for significant fibrosis, ≥F2).

RESULTS

HOMA-IR gradually increased in CHB, CHC and NAFLD: 2.3±1.8; 3±2.6 and 3.8±2.7 (p<0.001). The prevalence of steatosis >5% was 21% (CHB), 43% (CHC) and 82% (NAFLD), (p<0.001). The prevalence of fibrosis≥F2 was 10% (CHB), 42% (CHC) and 21% (NAFLD), p<0.001. In CHB, IR was related to host and not viral factors. CHB patients with steatosis had higher BMI (29±5.7kg/m(2) vs. 24±4kg/m(2), p<0.001), waist circumference (96±14cm vs. 84±11cm, p=0.001) and HOMA-IR (3.9±2.6 vs. 1.8±1.2, p<0.001) than those without steatosis. HOMA-IR independently predicted steatosis in CHB (OR=1.9, 95% CI, 1.09-3.27, p<0.05) and CHC (OR=1.38; 95% CI, 1.07-1.78, p<0.02). In CHB, metabolic risk factors and HOMA-IR were not associated with significant fibrosis. HOMA-IR was an independent predictor of fibrosis in CHC.

CONCLUSIONS

Steatosis may co-exist in CHB patients but with a lower prevalence than in CHC and NAFLD. In CHB steatosis is related to host and not viral factors, and is not associated with the severity of fibrosis.

MTA1--a stress response protein: a master regulator of gene expression and cancer cell behavior

Gene mutation's role in initiating carcinogenesis has been controversial, but it is consensually accepted that both carcinogenesis and cancer metastasis are gene-regulated processes. MTA1, a metastasis-associated protein, has been extensively researched, especially regarding its role in cancer metastasis. In this review, I try to elucidate MTA1's role in both carcinogenesis and metastasis from a different angle. I propose that MTA1 is a stress response protein that is upregulated in various stress-related situations such as heat shock, hypoxia, and ironic radiation. Cancer cells are mostly living in a stressful environment of hypoxia, lack of nutrition, and immune reaction attacks. To cope with all these stresses, MTA1 expression is upregulated, plays a role of master regulator of gene expression, and helps cancer cells to survive and migrate out of their original dwelling.

Immunopathogenesis of chronic hepatitis B

Chronic hepatitis B (CHB) is a widespread infectious disease with unfavorable outcomes and life-threatening consequences for patients, in spite of modern vaccination and antiviral treatment modalities. Cutting-edge experimental approaches have demonstrated key pathways that involve cross-talk between viral particles and host immune cells. All events, including penetration of hepatitis B virus (HBV) particles into host cells, establishing persistence, and chronization of CHB infection, and possibility of complete elimination of HBV particles are controlled by the immune system. Researchers have paid special attention to the replication capacity of HBV in host cells, which is associated with cellular changes that reflect presentation of viral antigens and variability of HBV antigen features. In addition, specific HBV proteins have an immune-modulating ability to initiate molecular mechanisms that “avoid” control by the immune system. The relationship between immunological shifts and chronic infection stages has been intensively studied since it was recognized that the immune system is a direct participant in the recurrent (cyclic) nature of CHB. Understanding the wide diversity of molecular pathways and the crosstalk between innate and adaptive immune system components will provide fresh insight into CHB immune pathogenesis and the possibilities of developing new treatment strategies for this disease.

Protective role of macrophage migration inhibitory factor in nonalcoholic steatohepatitis

MIF is an inflammatory cytokine but is hepatoprotective in models of hepatotoxin-induced liver fibrosis. Hepatic fibrosis can also develop from metabolic liver disease, such as nonalcoholic fatty liver disease (NASH). We investigated the role of MIF in high-fat or methionine- and choline-deficient diet mouse models of NASH. Mif(-/-) mice showed elevated liver triglyceride levels (WT, 53±14 mg/g liver; Mif(-/-), 103±7 mg/g liver; P<0.05) and a 2-3-fold increased expression of lipogenic genes. Increased fatty degeneration in the livers of Mif(-/-) mice was associated with increased hepatic inflammatory cells (1.6-fold increase in F4/80(+) macrophages) and proinflammatory cytokines (e.g., 2.3-fold increase in Tnf-α and 2-fold increase in Il-6 expression). However, inflammatory cells and cytokines were decreased by 50-90% in white adipose tissue (WAT) of Mif(-/-) mice. Subset analysis showed that macrophage phenotypes in livers of Mif(-/-) mice were skewed toward M2 (e.g., 1.7-fold and 2.5-fold increase in Arg1 and Il-13, respectively, and 2.5-fold decrease in iNos), whereas macrophages were generally reduced in WAT of these mice (70% reduction in mRNA expression of F4/80(+) macrophages). The protective MIF effect was scrutinized in isolated hepatocytes. MIF reversed inflammation-induced triglyceride accumulation in Hepa1-6 cells and primary hepatocytes and also attenuated oleic acid-elicited triglyceride increase in 3T3-L1 adipocytes. Protection from fatty hepatocyte degeneration was paralleled by a 2- to 3-fold reduction by MIF of hepatocyte proinflammatory cytokine production. Blockade of MIF receptor cluster of differentiation 74 (CD74) but not of CXCR2 or CXCR4 fully reverted the protective effect of MIF, comparable to AMPK inhibition. In summary, we demonstrate that MIF mediates hepatoprotection through the CD74/AMPK pathway in hepatocytes in metabolic models of liver injury.

Chronic ethanol consumption inhibits glucokinase transcriptional activity by Atf3 and triggers metabolic syndrome in vivo

Chronic ethanol consumption induces pancreatic β-cell dysfunction through glucokinase (Gck) nitration and down-regulation, leading to impaired glucose tolerance and insulin resistance, but the underlying mechanism remains largely unknown. Here, we demonstrate that Gck gene expression and promoter activity in pancreatic β-cells were suppressed by chronic ethanol exposure in vivo and in vitro, whereas expression of activating transcription factor 3 (Atf3) and its binding to the putative Atf/Creb site (from −287 to −158 bp) on the Gck promoter were up-regulated. Furthermore, in vitro ethanol-induced Atf3 inhibited the positive effect of Pdx-1 on Gck transcriptional regulation, enhanced recruitment of Hdac1/2 and histone H3 deacetylation, and subsequently augmented the interaction of Hdac1/Pdx-1 on the Gck promoter, which were diminished by Atf3 siRNA. In vivo Atf3-silencing reversed ethanol-mediated Gck down-regulation and β-cell dysfunction, followed by the amelioration of impaired glucose tolerance and insulin resistance. Together, we identified that ethanol-induced Atf3 fosters β-cell dysfunction via Gck down-regulation and that its loss ameliorates metabolic syndrome and could be a potential therapeutic target in treating type 2 diabetes. The Atf3 gene is associated with the induction of type 2 diabetes and alcohol consumption-induced metabolic impairment and thus may be the major negative regulator for glucose homeostasis.

The roles of hepatitis B virus-encoded X protein in virus replication and the pathogenesis of chronic liver disease

INTRODUCTION

Hepatitis B virus (HBV) is a major cause of chronic liver disease (CLD) and hepatocellular carcinoma (HCC) worldwide. More than 350 million people are at risk for HCC, and with few treatment options available, therapeutic approaches to targets other than the virus polymerase will be needed. This review suggests that the HBV-encoded X protein, HBx, would be an outstanding target because it contributes to the biology and pathogenesis of HBV in three fundamental ways.

AREAS COVERED

First, HBx is a trans-activating protein that stimulates virus gene expression and replication, thereby promoting the development and persistence of the carrier state. Second, HBx partially blocks the development of immune responses that would otherwise clear the virus, and protects infected hepatocytes from immune-mediated destruction. Thus, HBx contributes to the development of CLD without virus clearance. Third, HBx alters patterns of host gene expression that make possible the emergence of HCC. The selected literature cited is from the National Library of Medicine (Pubmed and Medline).

EXPERT OPINION

Understanding the mechanisms, whereby HBx supports virus replication and promotes pathogenesis, suggests that HBx will be an important therapeutic target against both virus replication and CLD aimed at the chemoprevention of HCC.

Neuroendocrine and metabolic components of dopamine agonist amelioration of metabolic syndrome in SHR rats

BACKGROUND

The hypertensive, pro-inflammatory, obese state is strongly coupled to peripheral and hepatic insulin resistance (in composite termed metabolic syndrome [MS]). Hepatic pro-inflammatory pathways have been demonstrated to initiate or exacerbate hepatic insulin resistance and contribute to fatty liver, a correlate of MS. Previous studies in seasonally obese animals have implicated an important role for circadian phase-dependent increases in hypothalamic dopaminergic tone in the maintenance of the lean, insulin sensitive condition. However, mechanisms driving this dopaminergic effect have not been fully delineated and the impact of such dopaminergic function upon the above mentioned parameters of MS, particularly upon key intra-hepatic regulators of liver inflammation and lipid and glucose metabolism have never been investigated.

OBJECTIVE

This study therefore investigated the effects of timed daily administration of bromocriptine, a potent dopamine D2 receptor agonist, on a) ventromedial hypothalamic catecholamine activity, b) MS and c) hepatic protein levels of key regulators of liver inflammation and glucose and lipid metabolism in a non-seasonal model of MS - the hypertensive, obese SHR rat.

METHODS

Sixteen week old SHR rats maintained on 14 hour daily photoperiods were treated daily for 16 days with bromocriptine (10 mg/kg, i.p.) or vehicle at 1 hour before light offset and, subsequent to blood pressure recordings on day 14, were then utilized for in vivo microdialysis of ventromedial hypothalamic catecholamine activity or sacrificed for the analyses of MS factors and regulators of hepatic metabolism. Normal Wistar rats served as wild-type controls for hypothalamic activity, body fat levels, and insulin sensitivity.

RESULTS

Bromocriptine treatment significantly reduced ventromedial hypothalamic norepinephrine and serotonin levels to the normal range and systolic and diastolic blood pressures, retroperitoneal body fat level, plasma insulin and glucose levels and HOMA-IR relative to vehicle treated SHR controls. Such treatment also reduced plasma levels of C-reactive protein, leptin, and norepinephrine and increased that of plasma adiponectin significantly relative to SHR controls. Finally, bromocriptine treatment significantly reduced hepatic levels of several pro-inflammatory pathway proteins and of the master transcriptional activators of lipogenesis, gluconeogenesis, and free fatty acid oxidation versus control SHR rats.

CONCLUSION

These findings indicate that in SHR rats, timed daily dopamine agonist treatment improves hypothalamic and neuroendocrine pathologies associated with MS and such neuroendocrine events are coupled to a transformation of liver metabolism potentiating a reduction of elevated lipogenic and gluconeogenic capacity. This liver effect may be driven in part by concurrent reductions in hyperinsulinemia and sympathetic tone as well as by reductions in intra-hepatic inflammation.

Growth inhibition of hepatocellular carcinoma Huh7 cells by Lactobacillus casei extract

PURPOSE

Lactobacillus casei (L. casei) is known to exert anti-proliferation effects on many types of cancer cells. However, the effect of L. casei on liver cancer has not been reported. Accordingly, the aim of this study was to determine the anti-cancer effect of L. casei extract on Huh7 cells.

MATERIALS AND METHODS

L. casei ATCC393 extract was prepared and purified. After the treatment of L. casei extract on Huh7 cells, cell viability, cell cycle arrest and cell death were analyzed by flow cytometry. The expression levels of tumor necrosis factor-α receptor 1 (TNFR1) and death receptor 3 (DR3) mRNA related with extrinsic apoptosis were assessed by reverse transcription polymerase chain reaction. Additionally, P21 and P27 cell cycle proteins as well as Caspase-3, -8, -9, phospho-Bad and Bcl-2 apoptosis proteins were analyzed by western blot analysis. To determine the effect of L. casei extract on cancer stem-like cells, we analyzed changes in side population fraction through flow cytometry.

RESULTS

The cell viability of Huh7 cells treated with L. casei extract was decreased by 77%, potentially owing to increases in the rates of Huh7 cells arrested in the G2/M phase (3% increase) and that underwent apoptosis (6% increase). The expression levels of TNFR1 and DR3 mRNA, as well as P21 and P27 cell cycle proteins, were increased. Meanwhile, the expressions of caspase-8, -9, phospho-Bad and Bcl-2 proteins decreased. However, in the case of side population cells, no remarkable changes were observed.

CONCLUSION

L. casei extract exerts a potent anti-tumor effect on the viability of liver cancer cells, although not on cancer stem-like cells.

Hepatocystin/80K-H inhibits replication of hepatitis B virus through interaction with HBx protein in hepatoma cell

Hepatitis B virus (HBV) X protein (HBx) is a key player in HBV replication as well as HBV-induced hepatocellular carcinoma (HCC). However, the pathogenesis of HBV infection and the mechanisms of host-virus interactions are still elusive. In this study, a combination of affinity purification and mass spectrometry was applied to identify the host factors interacting with HBx in hepatoma cells. Thirteen proteins were identified as HBx binding partners. Among them, we first focused on determining the functional significance of the interaction between HBx and hepatocystin. A physical interaction between HBx and hepatocystin was confirmed by co-immunoprecipitation and Western blotting. Immunocytochemistry demonstrated that HBx and hepatocystin colocalized in the hepatoma cells. Domain mapping of both proteins revealed that the HBx C-terminus (amino acids 110-154) was responsible for binding to the mannose 6-phosphate receptor homology domain (amino acids, 419-525) of hepatocystin. Using translation and proteasome inhibitors, we found that hepatocystin overexpression accelerated HBx degradation via a ubiquitin-independent proteasome pathway. We demonstrated that this effect was mediated by an interaction between both proteins using a HBx deletion mutant. Hepatocystin overexpression significantly inhibited HBV DNA replication and expression of HBs antigen concomitant with HBx degradation. Using the hepatocystin mutant constructs that bind HBx, we also confirmed that hepatocystin inhibited HBx-dependent HBV replication. In conclusion, we demonstrated for the first time that hepatocystin functions as a chaperon-like molecule by accelerating HBx degradation, and thereby inhibits HBV replication. Our results suggest that inducing hepatocystin may provide a novel therapeutic approach to control HBV infection.

Transcriptomic signature to oxidative stress exposure at the time of embryonic genome activation in bovine blastocysts

In order to understand how in vitro culture affects embryonic quality, we analyzed survival and global gene expression in bovine blastocysts after exposure to increased oxidative stress conditions. Two pro-oxidant agents, one that acts extracellularly by promoting reactive oxygen species (ROS) production (0.01 mM 2,2'-azobis (2-amidinopropane) dihydrochloride [AAPH]) or another that acts intracellularly by inhibiting glutathione synthesis (0.4 mM buthionine sulfoximine [BSO]) were added separately to in vitro culture media from Day 3 (8-16-cell stage) onward. Transcriptomic analysis was then performed on resulting Day-7 blastocysts. In the literature, these two pro-oxidant conditions were shown to induce delayed degeneration in a proportion of Day-8 blastocysts. In our experiment, no morphological difference was visible, but AAPH tended to decrease the blastocyst rate while BSO significantly reduced it, indicating a differential impact on the surviving population. At the transcriptomic level, blastocysts that survived either pro-oxidant exposure showed oxidative stress and an inflammatory response (ARRB2), although AAPH induced higher disturbances in cellular homeostasis (SERPINE1). Functional genomics of the BSO profile, however, identified differential expression of genes related to glycine metabolism and energy metabolism (TPI1). These differential features might be indicative of pre-degenerative blastocysts (IGFBP7) in the AAPH population whereas BSO exposure would select the most viable individuals (TKDP1). Together, these results illustrate how oxidative disruption of pre-attachment development is associated with systematic up-regulation of several metabolic markers. Moreover, it indicates that a better capacity to survive anti-oxidant depletion may allow for the survival of blastocysts with a quieter metabolism after compaction.

Influence of block of NF-kappa B signaling pathway on oxidative stress in the liver homogenates

The aim of the present study was to assess whether BAY 11-7082, a nuclear factor-kappaB (NF-κB) inhibitor, influences the level of reactive oxygen species (ROS), tumor necrosis factor alpha (TNF-α), and NF-κB related signaling pathways in the liver. The animals were divided into 4 groups: I: saline; II: saline + endothelin-1 (ET-1) (1.25 μg/kg b.w., i.v.); III: saline + ET-1 (12.5 μg/kg b.w., i.v.); and IV: BAY 11-7082 (10 mg/kg b.w., i.v.) + ET-1 (12.5 μg/kg b.w., i.v.). Injection of ET-1 alone at a dose of 12.5 μg/kg b.w. showed a significant (P < 0.001) increase in thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H₂O₂) level and decrease (P < 0.01) in GSH level (vs. control). ET-1 administration slightly downregulated gene expression of p65 of NF-κB but potently and in a dose-dependent way downregulated p21-cip gene expression in the liver. BAY 11-7082 significantly decreased TBARS (P < 0.001), H₂O₂ (P < 0.01) and improved the redox status (P < 0.05), compared to ET-1 group. The concentration of TNF-α was increased in the presence of ET-1 (P < 0.05), while BAY 11-7082 decreased TNF-α concentration (P < 0.01). Inhibition of IkBα before ET-1 administration downregulated gene expression of p21-cip but had no effect on p65.

HBV-related hepatocellular carcinoma: the role of integration, viral proteins and miRNA

The development of hepatocellular carcinoma during chronic hepatitis B infection is a multifactorial process thought to be a consequence of several direct and indirect mechanisms. In this review we discuss how viral proteins and cycles of ongoing liver damage and regeneration, coupled with HBV DNA integration and aberrant miRNA expression may enhance the risk for the development of hepatocellular carcinoma.

Differential functions of C- and N-terminal hepatitis B x protein in liver cells treated with doxorubicin in normoxic or hypoxic condition

Hepatitis viral B x protein (HBx), a hepatocarcinogen, is frequently mutated. Hypoxia influences the growth of HCC and also the sensitivity of tumor cells to treatments. We aimed to test the role of HBx and acute hypoxia in the efficacy of chemotherapy. In this study, we established 4 Chang liver cell lines with the full-length HBx (HBx), the first 50 amino acids of N-terminal HBx (HBx/50), the last 104 amino acids of C-terminal HBx (HBx/51) and empty vector (CL), respectively. MTT and TNUEL assays were used to assess cell viability and apoptosis respectively. Western blot was used to determine the expression of relevant proteins. Results showed that among 4 cell lines, doxorubicin was most effective in decreasing the viability and enhancing apoptosis in HBx/51 cells, while HBx/50 cells were most resistant to the treatment. Cells in hypoxia were more susceptible to doxorubicin than cells in normoxia. Hypoxia facilitated the Bid cleavage especially in HBx/51 cells via phosphorylating p38 MAPK. p38 MAPK inhibitor significantly reduced the tBid level and increased cell viability. In conclusion, N-terminal HBx and C-terminal HBx function differentially in their ability to regulate cell growth, with the former being promotive but the latter being inhibitory. The acute hypoxia may overcome the HBx-induced resistance and facilitate the chemotherapy.

Hepatitis B virus encoded X protein suppresses apoptosis by inhibition of the caspase-independent pathway

Hepatitis B virus (HBV) encoded X protein (HBx) has been implicated in apoptotic and related pathogenic events during hepatocellular carcinoma. However, the underlying molecular mechanism through which HBx acts is largely unclear. We used tandem affinity purification under mild conditions to gain insight into the HBx interactome in HBV-producing HepG2.2.15 cells and identified 49 proteins by mass spectrometry that are potentially associated with HBx. Two of the key proteins of the caspase-independent apoptosis pathway were newly identified, apoptosis-inducing factor (AIF) and the homologous AMID (AIF-homologue mitochondrion-associated inducer of death). We confirmed the interactions of HBx with AIF and with AMID by reciprocal coimmunoprecipitation experiments, respectively. We observed the expression of HBx-reduced AIF-mediated apoptosis and HBx colocalization with AIF and AMID, principally in the cytoplasm. Furthermore, the elevated cytoplasmic levels of HBx could inhibit mitochondrion-to-nucleus translocation of AIF. Here, we present the first detailed molecular evidence that HBx can repress apoptosis via inhibition of the caspase-independent apoptosis pathway. This inhibition of apoptosis involves the repression of the mitochondrion-to-nucleus translocation of AIF, although tests with AMID were not conclusive. These findings provide important insights into the new mechanism of the apoptosis inhibition by HBV.

HBx induces HepG-2 cells autophagy through PI3K/Akt-mTOR pathway

Chronic hepatitis B virus infection is the dominant global cause of hepatocellular carcinoma (HCC), especially hepatitis B virus-X (HBx) plays a major role in this process. HBx protein promotes cell cycle progression, inactivates negative growth regulators, and binds to and inhibits the expression of p53 tumor suppressor gene and other tumor suppressor genes and senescence-related factors. However, the relationship between HBx and autophagy during the HCC development is poorly known. Previous studies found that autophagy functions as a survival mechanism in liver cancer cells. We suggest that autophagy plays a possible role in the pathogenesis of HBx-induced HCC. The present study showed that HBx transfection brought about an increase in the formation of autophagosomes and autolysosomes. Microtubule-associated protein light chain 3, Beclin 1, and lysosome-associated membrane protein 2a were up-regulated after HBx transfection. HBx-induced increase in the autophagic level was increased by mTOR inhibitor rapamycin and was blocked by treatment with the PI3K-Akt inhibitor LY294002. The same results can also be found in HepG2.2.15 cells. These results suggest that HBx activates the autophagic lysosome pathway in HepG-2 cells through the PI3K-Akt-mTOR pathway.

Do hepatitis B virus and hepatitis C virus co-infections increase hepatocellular carcinoma occurrence through synergistically modulating lipogenic gene expression?

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections cause a wide range of liver diseases including hepatocellular carcinoma (HCC). Because of the similar modes of transmission, HBV HCV co-infections are found in approximately 7-20 million people globally. Compared with HBV or HCV mono-infections, co-infections are associated with more severe liver diseases and higher risk of HCC. Abnormal lipid biosynthesis and metabolism has been increasingly recognized as a cause for cancer. While HBV infection does not seem to significantly increase the risk of developing hepatic steatosis, steatosis is a prominent feature of chronic hepatitis C (CHC). In addition, steatosis in HBV or HCV mono-infections is a significant and independent risk factor for HCC. However, whether and how HBV HCV co-infections synergistically increase the risk of HCC development through modulating lipid metabolism is not well understood. Possible mechanisms by which steatosis causes HCC include: activation of sterol regulatory element-binding protein-mediated lipogenesis through the PI3K-Akt pathway, abnormal activation of peroxisome proliferator-activated receptors and endoplasmic reticulum stress. Here, we review the potential mechanisms by which HBV HCV co-infections may increase HCC risk through modulation of lipogenic gene expression. We begin with reviewing the impact of HBV and HCV on host lipogenic gene expression and carcinogenesis. We then discuss the potential mechanisms by which HBV and HCV can increase carcinogenesis through synergistically activating lipid biosynthesis and metabolism. We end by sharing our thoughts on future research directions in this emerging paradigm with an ultimate goal of developing effective therapeutics.

Hepatitis B virus infection and fatty liver in the general population

BACKGROUND & AIMS

In animal studies, expression of hepatitis B virus (HBV) proteins causes hepatic steatosis. We aimed to study the prevalence of fatty liver in people with and without HBV infection in the general population.

METHODS

We performed a cross-sectional population study in Hong Kong Chinese. Intrahepatic triglyceride content (IHTG) was measured by proton-magnetic resonance spectroscopy.

RESULTS

One thousand and thirteen subjects (91 HBV patients and 922 controls) were recruited. The median IHTG was 1.3% (0.2-33.3) in HBV patients and 2.1% (0-44.2) in controls (p <0.001). Excluding subjects with significant alcohol consumption, the prevalence of nonalcoholic fatty liver disease was 13.5% (95% confidence interval [CI] 6.4%, 20.6%) in HBV patients and 28.3% (95% CI 25.3%, 31.2%) in controls (p=0.003). The fatty liver prevalence differed in HBV patients and controls aged 40-59 years but was similar in those aged 60 years or above. After adjusting for demographic and metabolic factors, HBV infection remained an independent factor associated with lower risk of fatty liver (adjusted odds ratio 0.42; 95% CI 0.20, 0.88; p=0.022). HBV patients also had a lower prevalence of metabolic syndrome (11.0% vs. 20.2%; p=0.034), but the difference was mainly attributed to lower triglyceride levels. Among HBV patients, viral genotypes, HBV DNA level and hepatitis B e antigen status were not associated with fatty liver.

CONCLUSIONS

HBV infection is associated with a lower prevalence of fatty liver, hypertriglyceridemia and metabolic syndrome. Viral replication may affect lipid metabolism and this warrants further studies.

Differential gene expression profile in bovine blastocysts resulting from hyperglycemia exposure during early cleavage stages

To understand the compromised survival of embryos derived from assisted reproductive techniques, transcriptome survey of early embryonic development has shown the impact of in vitro culture environment on gene expression in bovine or other living species. However, how the differentially expressed genes translate into developmentally compromised embryos is unresolved. We therefore aimed to characterize transcriptomic markers expressed by bovine blastocysts cultured in conditions that are known to impair embryo development. As increasing glucose concentrations has been shown to be stressful for early cleavage stages of mammalian embryos and to decrease subsequent blastocyst survival, in vitro-matured/fertilized bovine zygotes were cultured in control (0.2 mM) or high-glucose (5 mM) conditions until the 8- to 16-cell stage, and then transferred to control media until they reached the blastocyst stage. The concentration of 5 mM glucose was chosen as a stress treatment because there was a significant effect on blastocyst rate without the treatment's being lethal as with 10 mM. Microarray analysis revealed gene expression differences unrelated to embryo sex or hatching. Overrepresented processes among differentially expressed genes in treated blastocysts were extracellular matrix signalling, calcium signaling, and energy metabolism. On a pathophysiological level, higher glucose treatment impacts pathways associated with diabetes and tumorigenesis through genes controlling the Warburg effect, i.e., emphasis on use of anaerobic glycolysis rather than oxidative phosphorylation. These results allowed us to conclude that disruption of in vitro preattachment development is concomitant with gene expression modifications involved in metabolic control.

An autoimmunized mouse model recapitulates key features in the pathogenesis of Sjögren's syndrome

The pathogenesis of Sjögren's syndrome (SS) is poorly understood. To evaluate an autoimmunization-induced experimental SS model, we firstly observed the phenotype of lymphocyte infiltration in the enlarged submandibular gland (SG). Furthermore, significant activation of caspase-3 and a high ratio of Bax-to-Bcl-2 were detected, indicating the inflammatory apoptosis associated with developmental foci. Meanwhile, the dysregulated cytokines, such as tumor necrosis factor α, IL-1β and IL-6 mRNA expression, were found to be over-expressed. A progressive decrease of aquaporin 5 and its subcellular translocation from apical to basal membrane in SG was found to be associated with the abnormally expressed M3 muscarinic acetylcholine receptor. This pattern was found to be similar to that seen in human SS and possibly contributed to the saliva secretion deficiency. Thus, this autoimmunization-induced model recapitulates the key features of human SS and may have potential for studying the pathogenesis of human SS.