Enhanced antiviral and antifibrotic effects of short hairpin RNAs targeting HBV and TGF-β in HBV-persistent mice

From hepatitis B virus infection to acute-on-chronic liver failure: The dynamic role of hepatic macrophages

Acute-on-chronic liver failure (ACLF) is a progressive disease that is associated with rapid worsening of clinical symptoms and high mortality. A multicentre prospective study from China demonstrated that patients with hepatitis B virus-related ACLF (HBV-ACLF) exhibited worse clinical characteristics and higher mortality rates compared to non-HBV-ACLF patients. Immune dysregulation is closely linked to the potential mechanisms of initiation and progression of ACLF. Innate immune response, which is represented by monocytes/macrophages, is up-regulated across ACLF development. This suggests that monocytes/macrophages play an essential role in maintaining the immune homeostasis of ACLF. Information that has been published in recent years shows that the immune status and function of monocytes/macrophages vary in ACLF precipitated by different chronic liver diseases. Monocytes/macrophages have an immune activation effect in hepatitis B-precipitated-ACLF, but they exhibit an immune suppression in cirrhosis-precipitated-ACLF. Therefore, this review aims to explain whether this difference affects the clinical outcome in HBV-ACLF patients as well as the mechanisms involved. We summarize the novel findings that highlight the dynamic polarization phenotype and functional status of hepatic macrophages from the stage of HBV infection to ACLF development. Moreover, we discuss how different HBV-related liver disease tissue microenvironments affect the phenotype and function of hepatic macrophages. In summary, increasing developments in understanding the differences in immune phenotype and functional status of hepatic macrophages in ACLF patients will provide new perspectives towards the effective restoration of ACLF immune homeostasis.

AAV Immunotoxicity: Implications in Anti-HBV Gene Therapy

Hepatitis B virus (HBV) has afflicted humankind for decades and there is still no treatment that can clear the infection. The development of recombinant adeno-associated virus (rAAV)-based gene therapy for HBV infection has become important in recent years and research has made exciting leaps. Initial studies, mainly using mouse models, showed that rAAVs are non-toxic and induce minimal immune responses. However, several later studies demonstrated rAAV toxicity, which is inextricably associated with immunogenicity. This is a major setback for the progression of rAAV-based therapies toward clinical application. Research aimed at understanding the mechanisms behind rAAV immunity and toxicity has contributed significantly to the inception of approaches to overcoming these challenges. The target tissue, the features of the vector, and the vector dose are some of the determinants of AAV toxicity, with the latter being associated with the most severe adverse events. This review discusses our current understanding of rAAV immunogenicity, toxicity, and approaches to overcoming these hurdles. How this information and current knowledge about HBV biology and immunity can be harnessed in the efforts to design safe and effective anti-HBV rAAVs is discussed.

Diagnostic Role of Circulating miRNAs in the Grading of Chronic Hepatitis B-Related Liver Fibrosis: A Systematic Review and Meta-Analysis

OBJECTIVE

miRNAs are considered potential biomarkers that can be used for the grading of chronic hepatitis B (CHB)-related liver fibrosis. This meta-analysis aims to elucidate the diagnostic performance of miRNAs.

METHODS

Databases were used to search for meta-analyses. A bivariate model was used to calculate pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). In addition, the area under the summary receiver operating characteristic curve (AUC) and 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 9 studies with 1159 patients with CHB-related liver fibrosis were assessed. For diagnosis of significant liver fibrosis, the pooled sensitivity, specificity, PLR, NLR, DOR, and AUC were 0.73 (95% CI, 0.68-0.78), 0.78 (95% CI, 0.70-0.84), 3.32 (95% CI, 2.52-4.37), 0.34 (95% CI, 0.30-0.39), 9.70 (95% CI, 7.10-13.24), and 0.81 (95% CI, 0.77-0.84), respectively.

CONCLUSION

miRNAs are potential biomarkers of CHB-related liver fibrosis.

Advances in designing Adeno-associated viral vectors for development of anti-HBV gene therapeutics

Despite the five decades having passed since discovery of the hepatitis B virus (HBV), together with development of an effective anti-HBV vaccine, infection with the virus remains a serious public health problem and results in nearly 900,000 annual deaths worldwide. Current therapies do not eliminate the virus and viral replication typically reactivates after treatment withdrawal. Hence, current endeavours are aimed at developing novel therapies to achieve a functional cure. Nucleic acid-based therapeutic approaches are promising, with several candidates showing excellent potencies in preclinical and early stages of clinical development. However, this class of therapeutics is yet to become part of standard anti-HBV treatment regimens. Obstacles delaying development of gene-based therapies include lack of clinically relevant delivery methods and a paucity of good animal models for preclinical characterisation. Recent studies have demonstrated safety and efficiency of Adeno-associated viral vectors (AAVs) in gene therapy. However, AAVs do have flaws and this has prompted research aimed at improving design of novel and artificially synthesised AAVs. Main goals are to improve liver transduction efficiencies and avoiding immune clearance. Application of AAVs to model HBV replication in vivo is also useful for characterising anti-HBV gene therapeutics. This review summarises recent advances in AAV engineering and their contributions to progress with anti-HBV gene therapy development.

Advances with RNAi-Based Therapy for Hepatitis B Virus Infection

Infection with hepatitis B virus (HBV) remains a global health challenge. Approximately 292 million people worldwide are chronically infected with HBV and the annual mortality from the infection is approaching 900,000. Despite the availability of an effective prophylactic vaccine, millions of individuals are at risk of potentially fatal complicating cirrhosis and hepatocellular carcinoma. Current drug treatments can suppress viral replication, slow the progression of liver fibrosis, and reduce infectivity, but can rarely clear the viral covalently closed circular DNA (cccDNA) that is responsible for HBV persistence. Alternative therapeutic strategies, including those based on viral gene silencing by harnessing the RNA interference (RNAi) pathway, effectively suppress HBV replication and thus hold promise. RNAi-based silencing of certain viral genes may even lead to disabling of cccDNA during chronic infection. This review summarizes different RNAi activators that have been tested against HBV, the advances with vectors used to deliver artificial potentially therapeutic RNAi sequences to the liver, and the current status of preclinical and clinical investigation.

Applications of Virus Vector-Mediated Gene Therapy in China

Due to the increased safety and efficiency of virus vectors, virus vector-mediated gene therapy is now widely used for various diseases, including monogenic diseases, complex disorders, and infectious diseases. Recent gene therapy trials have shown significant therapeutic benefits, and Chinese researchers have contributed significantly to this progress. This review highlights disease applications and strategies for virus vector-mediated gene therapy in preclinical studies and clinical trials in China.

HBV and HIV/HBV Infected Patients Have Distinct Immune Exhaustion and Apoptotic Serum Biomarker Profiles

Background:

Hepatitis B virus (HBV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Due to their shared routes of transmission, approximately 10% of HIV-infected patients worldwide are chronically coinfected with HBV. Additionally, liver disease has become a major cause of morbidity and mortality in HBV/HIV coinfected patients due to prolonged survival with the success of antiretroviral therapy. The relationship between immune exhaustion markers (PD-1/PD-L1) and apoptotic markers such as Fas/FasL, TGFβ1, TNF-α, and Th1/Th2 cytokines are not clearly delineated in HBV/HIV coinfection.

Methods:

Levels of soluble Fas/FasL, TGFβ1, TNF-α, and sPD-1/sPD-L1 as well as Th1 and Th2 cytokines were evaluated in the sera of HBV-monoinfected (n = 30) and HBV/HIV-coinfected (n = 15) patients and compared to levels in healthy controls (n = 20).

Results:

HBV-monoinfected patients had significantly lower levels of the anti-inflammatory cytokine IL-4 (P < 0.05) and higher levels of apoptotic markers sFas, sFasL, and TGFβ-1 (P < 0.001) compared to healthy controls. Coinfection with HIV was associated with higher levels of sFas, TNF-α, and sPD-L1 (P < 0.005), and higher levels of the pro-inflammatory cytokines IL-6, IL-8, and IL-12p70 (P < 0.05) compared to healthy controls. Patients with HBV infection had a unique biomarker clustering profile comprised of IFN-γ, IL12p70, IL-10, IL-6, and TNF-α that was distinct from the profile of the healthy controls, and the unique HIV/HBV profile comprised GM-CSF, IL-4, IL-2, IFN-γ, IL12p70, IL-7, IL-10, and IL-1β. In HBV monoinfection a significant correlation between sFasL and PD1(r = 0.46, P = < 0.05) and between sFas and PDL1 (r = 0.48, P = <0.01) was observed.

Conclusion:

HBV-infected and HBV/HIV-coinfected patients have unique apoptosis and inflammatory biomarker profiles that distinguish them from each other and healthy controls. The utilization of those unique biomarker profiles for monitoring disease progression or identifying individuals who may benefit from novel immunotherapies such as anti-PD-L1 or anti-PD-1 checkpoint inhibitors appears promising and warrants further investigation.