Repression of Death Receptor-Mediated Apoptosis of Hepatocytes by Hepatitis B Virus e Antigen

The outcomes and mechanisms of chronic hepatitis B complicated by metabolic dysfunction-associated steatotic liver disease

BACKGROUND

In recent years, the rising prevalence of obesity and metabolic syndrome has led to an increased number of individuals developing metabolic dysfunction-associated steatotic liver disease (MASLD). Furthermore, given the substantial global prevalence of chronic hepatitis B (CHB), instances of MASLD coexisting with CHB are becoming increasingly commonplace in clinical scenarios. Both conditions can lead to liver fibrosis, cirrhosis, and potentially hepatocellular carcinoma (HCC). However, the intricacies of the dual etiology, consequential outcomes, and associated risks of CHB concurrent with MASLD are still not fully understood.

DATA SOURCES

A literature search was conducted on PubMed for articles published up to March 2024. The search keywords included nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, chronic hepatitis B, liver fibrosis, hepatocellular carcinoma, nuclear factor erythroid 2-related factor 2, and oxidative stress.

RESULTS

This review examined recent studies on the interplay between MASLD and CHB. The coexistence of these conditions may facilitate the clearance of hepatitis B surface antigen from the serum and impede hepatitis B virus (HBV) replication. Conversely, individuals with coexisting CHB tend to exhibit a lower rate of hypertriglyceridemia and reduced serum triglyceride levels compared with those only having NAFLD. Nevertheless, these observations do not necessarily indicate universally positive outcomes. Indeed, MASLD and CHB may synergistically act as "co-conspirators" to exacerbate clinical manifestations, particularly liver fibrosis and HCC.

CONCLUSIONS

As our understanding of the interaction between steatosis and HBV infection becomes clearer, we can better assess the risk of advanced liver disease in patients with concurrent CHB and MASLD. These insights will support the exploration of potential underlying mechanisms and may provide recommendations for improving patient outcomes.

FAS mediates apoptosis, inflammation, and treatment of pathogen infection

The FAS cell surface death receptor, a member of the tumor necrosis factor receptor family, activates both apoptotic and non-apoptotic signaling upon interaction with its ligand FASL. It is critical in cell migration, invasion, immune responses, and carcinogenesis. Pathogen infection can influence host cells' behavior by modulating the FAS/FASL pathway, thereby influencing disease progression. Understanding the role of FAS signaling in the context of pathogen interactions is therefore crucial. This review examines FAS-mediated apoptotic and non-apoptotic signaling pathways, with particular emphasis on the mechanisms of apoptosis and inflammation induced by bacterial and viral infections. Additionally, it highlights therapeutic strategies, including drug, cytokine, antibody, and FASL recombinant protein therapies, providing new directions for treating pathogenic infections and cancers, as well as insights into developing novel therapeutic approaches.

A narrative review: exploring viral-induced malignancies through the lens of dysregulated cellular metabolism and glucose transporters

INTRODUCTION

In this narrative review, we unravel the complex interplay between oncogenic viruses, cellular metabolism, and glucose transporter (GLUT) dysregulation in viral-induced malignancies.

METHODS

By explaining the diverse mechanisms through which seven major oncoviruses manipulate metabolic pathways and GLUT expression, particularly GLUT1, we provide novel insights into the critical role of metabolic reprogramming in viral replication and oncogenesis.

RESULTS

Our exploration of the molecular pathways targeted by viral oncoproteins reveals a similarity between the metabolic alterations induced by viral infections and those observed in neoplastic transformation. A key finding of our review is the overexpression of GLUTs, particularly GLUT1, as a hallmark of both viral infections and many cancers.

CONCLUSIONS

By elucidating the complex interplay between viral oncoproteins, oncogene activation, tumor suppressor gene loss, and GLUT overexpression, we highlight the potential of GLUTs as novel targets for diagnosis, prognosis, and therapy of viral-induced malignancies.

Advancing prognostic understanding in hepatocellular carcinoma through the integration of genomic instability and lncRNA signatures: GILncSig model

The recently published study by Duan et al introduces a promising method that combines genomic instability and long non-coding RNAs to improve the prognostic evaluation of hepatocellular carcinoma (HCC), a deadly cancer associated with considerable morbidity and mortality. This editorial aims to analyze the methodology, key findings, and broader implications of the study within the fields of gastroenterology and oncological surgery, highlighting the shift towards precision medicine in the management of HCC.

A novel phthalazinone derivative as a capsid assembly modulator inhibits hepatitis B virus expression

Development of new anti-hepatitis B virus (HBV) drugs that target viral capsid assembly is a very active research field. We identify a novel phthalazinone derivative, compound 5832, as a potent HBV inhibitor. In this study, we intend to elaborate the antiviral effect and mechanism of 5832 against HBV in vitro and in vivo. Compound 5832 treatment induces the formation of genome-free empty capsid by interfering with the core protein assembly domain, which significantly decreases the extracellular and intracellular HBV DNA. In the AAV-HBV transduced mouse model, 5832 suppresses serum HBV DNA after 4-week treatment, and decreases HBsAg and HBeAg levels. 5832 treatment also reduces intrahepatic HBV RNA, DNA and HBcAg levels. During the follow-up period after treatment withdrawal, serum antigen levels demonstrated no increase. We demonstrate 5832 treatment could active apoptotic signaling by elevating the expression of death receptor 5 (DR5), which participated in corresponding HBcAg-positive hepatocyte eradication. Phthalazinone derivative 5832 may serve as a promising anti-HBV drug candidate to improve the treatment options for chronic HBV infection.

The Complex Role of HBeAg and Its Precursors in the Pathway to Hepatocellular Carcinoma

Hepatitis B virus (HBV) is one of the seven known human oncogenic viruses and has adapted to coexist with a single host for prolonged periods, requiring continuous manipulation of immunity and cell fate decisions. The persistence of HBV infection is associated with the pathogenesis of hepatocellular carcinoma, and various HBV proteins have been implicated in promoting this persistence. The precursor of hepatitis e antigen (HBeAg), is translated from the precore/core region and is post-translationally modified to yield HBeAg, which is secreted in the serum. HBeAg is a non-particulate protein of HBV and can act as both a tolerogen and an immunogen. HBeAg can protect hepatocytes from apoptosis by interfering with host signalling pathways and acting as a decoy to the immune response. By evading the immune response and interfering with apoptosis, HBeAg has the potential to contribute to the hepatocarcinogenic potential of HBV. In particular, this review summarises the various signalling pathways through which HBeAg and its precursors can promote hepatocarcinogenesis via the various hallmarks of cancer.

TRAIL inhibition by soluble death receptor 5 protects against acute myocardial infarction in rats

Acute myocardial infarction (AMI) is associated with high morbidity and mortality. An effective therapeutic strategy is to rescue cardiomyocytes from death. Apoptosis is a key reason of cardiomyocyte death that can be prevented. In this study, we investigated the role of TNF-related apoptosis-inducing ligand (TRAIL) in initiating apoptosis by binding to death receptor 5 (DR5), and this procession is inhibited by soluble DR5 (sDR5) in rats after AMI. First, we found that the level of TRAIL in serum was down-regulated in AMI patients. Then, TRAIL and DR5 expression was analysed in the myocardium of rats after AMI, and their expression was up-regulated. sDR5 treatment reduced the myocardial infarct size and the levels of CK-MB and cTn-I in serum. The expression of caspase 3 and PARP is decreased, but the anti-apoptotic factor Bcl-2 was increased in sDR5 treatment rats after AMI. DR5 expression was also analysed after sDR5 treatment and it was down-regulated, and a low level of DR5 expression seemed to be beneficial for the myocardium. Overall, our findings indicated that sDR5 decreases myocardial damage by inhibiting apoptosis in rat after AMI. We expect to observe the potential therapeutic effects of sDR5 on AMI in the future.

Hepatitis B virus e antigen and viral persistence

Hepatitis B virus (HBV) e antigen (HBeAg) was discovered in the sera of HBV patients nearly 50 years ago. It is not essential for HBV to infect or replicate in hepatocytes. Earlier clinical studies suggested that this antigen might play an important role for HBV to establish persistence in babies after its mother-to-child transmission. Subsequent clinical studies also suggested that HBeAg might have immunomodulatory activities. In recent years, a large body of information on how HBeAg might modulate host immunity was published. In this review, we summarize recent research progresses on the immunomodulatory activities of HBeAg and discuss how these activities of HBeAg may promote HBV persistence.

The role of MDM2-p53 axis dysfunction in the hepatocellular carcinoma transformation

Liver cancer is the second most frequent cause of cancer-related death globally. The main histological subtype is hepatocellular carcinoma (HCC), which is derived from hepatocytes. According to the epidemiologic studies, the most important risk factors of HCC are chronic viral infections (HBV, HCV, and HIV) and metabolic disease (metabolic syndrome). Interestingly, these carcinogenic factors that contributed to HCC are associated with MDM2-p53 axis dysfunction, which presented with inactivation of p53 and overactivation of MDM2 (a transcriptional target and negative regulator of p53). Mechanically, the homeostasis of MDM2-p53 feedback loop plays an important role in controlling the initiation and progression of HCC, which has been found to be dysregulated in HCC tissues. To maintain long-term survival in hepatocytes, hepatitis viruses have lots of ways to destroy the defense strategies of hepatocytes by inducing TP53 mutation and silencing, promoting MDM2 overexpression, accelerating p53 degradation, and stabilizing MDM2. As a result, genetic instability, chronic ER stress, oxidative stress, energy metabolism switch, and abnormalities in antitumor genes can be induced, all of which might promote hepatocytes' transformation into hepatoma cells. In addition, abnormal proliferative hepatocytes and precancerous cells cannot be killed, because of hepatitis viruses-mediated exhaustion of Kupffer cells and hepatic stellate cells (HSCs) and CD4+T cells by disrupting their MDM2-p53 axis. Moreover, inefficiency of hepatic immune response can be further aggravated when hepatitis viruses co-infected with HIV. Unlike with chronic viral infections, MDM2-p53 axis might play a dual role in glucolipid metabolism of hepatocytes, which presented with enhancing glucolipid catabolism, but promoting hepatocyte injury at the early and late stages of glucolipid metabolism disorder. Oxidative stress, fatty degeneration, and abnormal cell growth can be detected in hepatocytes that were suffering from glucolipid metabolism disorder, and all of which could contribute to HCC initiation. In this review, we focus on the current studies of the MDM2-p53 axis in HCC, and specifically discuss the impact of MDM2-p53 axis dysfunction by viral infection and metabolic disease in the transformation of normal hepatocytes into hepatoma cells. We also discuss the therapeutic avenues and potential targets that are being developed to normalize the MDM2-p53 axis in HCC.