Hepatitis B virus (HBV) X gene mutations and their association with liver disease progression in HBV-infected patients

Characterization of mutations in hepatitis B virus DNA isolated from Japanese HBsAg-positive blood donors in 2021 and 2022

Missense mutations in certain small envelope proteins diminish the efficacy of antibodies. Consequently, tracking the incidence and types of vaccine-escape mutations (VEMs) was crucial both before and after the introduction of universal hepatitis B vaccination in Japan in 2016. In this study, we isolated hepatitis B virus (HBV) DNA from 58 of 169 hepatitis B surface antigen (HBsAg)-positive blood samples from Japanese blood donors and determined the nucleotide sequence encoding the small envelope protein. DNA from six (10%) of the samples had VEMs, but no missense mutations, such as G145R, were detected. Complete HBV genome sequences were obtained from 29 of the 58 samples; the viral genotype was A1 in one (3%), A2 in three (10%), B1 in nine (31%), B2 in five (17%), B4 in one (3%), and C2 in 10 (34%) samples. Tenofovir-resistance mutations were detected in two (7%) samples. In addition, several core promoter mutations, such as 1762A>T and 1764G>A, and a precore nonsense mutation, 1986G>A, which are risk factors for HBV-related chronic liver disease, were detected. These findings provide a baseline for future research and highlight the importance of ongoing monitoring of VEMs and drug resistance mutations in HBV DNA from HBsAg-positive blood donors without HBV antibodies.

Relevance of HBx for Hepatitis B Virus-Associated Pathogenesis

The hepatitis B virus (HBV) counts as a major global health problem, as it presents a significant causative factor for liver-related morbidity and mortality. The development of hepatocellular carcinomas (HCC) as a characteristic of a persistent, chronic infection could be caused, among others, by the pleiotropic function of the viral regulatory protein HBx. The latter is known to modulate an onset of cellular and viral signaling processes with emerging influence in liver pathogenesis. However, the flexible and multifunctional nature of HBx impedes the fundamental understanding of related mechanisms and the development of associated diseases, and has even led to partial controversial results in the past. Based on the cellular distribution of HBx-nuclear-, cytoplasmic- or mitochondria-associated-this review encompasses the current knowledge and previous investigations of HBx in context of cellular signaling pathways and HBV-associated pathogenesis. In addition, particular focus is set on the clinical relevance and potential novel therapeutic applications in the context of HBx.

Association of HLADQ-B1 polymorphisms in three generations of chronic hepatitis B patients

The presence of polymorphisms in the human leukocyte antigen (HLA)-DQB1 gene, along with its expression, has been demonstrated to be correlated with spontaneous clearance and susceptibility to HBV infection. The present study aimed to evaluate the possible role of genetic polymorphisms in HLA-DQB1 in three generations of patients with chronic hepatitis B (CHB). Based on the inclusion criteria, 90 CHB patients, 18 individuals recovered from HBV infection, and 40 healthy subjects were chosen. The DNA contents of the whole blood samples were extracted in order to perform HLA-DQB1 typing by the PCR technique. Besides whole blood samples, sera were applied to measure liver function tests (LFTs), as well as the titers of anti-HDV and anti-HCV. Also, in all CHB patients were measured liver stiffness (LSM) by Fibro Scan. The results of HLA-DQB1 polymorphisms (rs2856718 and rs7453920) demonstrated that the majority of polymorphisms in CHB patients were HLA-DQB1*03, HLA-DQB1*05, HLA-DQB1*04:01 and HLA-DQB1*03:01 that associated with HBV persistence and chronicity. Among the patients who showed these polymorphisms, the mean±SD, LSM was 4±1.57 KPa and most of them, F grade was reported as F2, which was a sign of disease progression towards chronicity. HLA polymorphisms imputation revealed that HLA-DQB1*06:04 (3.4%, P-Value= 0.2) was detected only in healthy subjects as protective polymorphism, while the allele HLA-DQB1*03:03 was reported in both healthy subjects (P-Value= 0.06) and recovered patients (P-Value= 0.1) as suppressor of CHB formation. The allele HLA-DQB1*05:02 was found in both healthy subjects (3.4%) and CHB patients (4.5%) which was associated with risk to liver cirrhosis (P-Value= 0, OR: 0.002 0.95CI: 0.000-0.15). HLA polymorphism analysis indicated that 17.39% of patients who were seropositive for anti-HCV carried the HLA-DQB1*03:01. HBV resistance or infection risk could be assessed by DBQ1 typing. The existence of polymorphisms in HLA gene could influence the clearance (HLA-DQB1*03:03) or susceptibility and persistence of infection (HLA-DQB1*03, HLA-DQB1*05, HLA-DQB1*04:01 and HLA-DQB1*03:01). These results have the potential to improve personalized therapy and prognosis for HBV infection.

First Molecular Characterization of Chronic Hepatitis B Carriers in Timbuktu, Mali

In Mali, hepatocellular carcinoma (HCC) is the third and sixth most common cancer in men and women, respectively. Mali comprises several distinct climato-ecological zones. Most studies to date have been conducted in the sub-Sahelian zone of southern Mali, including the capital city Bamako. In this part of the country, the main risk factors for HCC are chronic hepatitis B virus (HBV) carriage and dietary exposure to aflatoxins, a well-known hepatocarcinogen. Data are scarce for other ecological zones, but our preliminary data from 721 blood donors in the area of Timbuktu, presented in this study, suggest that chronic HBV carriage is also endemic in the northern Saharan zone of Mali. For further study, 29 healthy HBV chronic carrier volunteers were recruited from the blood transfusion center in Timbuktu. Successful viral genotyping in 20 volunteers revealed HBV genotype E in 13 cases and D in 7 cases, suggesting that this geographical and anthropological transition zone may also represent a transition zone between HBV genotypes that dominate sub-Saharan and northern Africa, respectively. Sequencing of circulating cell-free plasma DNA (cfDNA) from donors did not reveal the presence of the TP53 R249S mutation in these donors, a marker of dietary exposure to aflatoxins in sub-Saharan Africa. These results suggest that the geo-epidemiological distribution of the risk factors for HCC is not uniform across Mali, but is dependent upon climatic, socioeconomic and anthropological factors that might have an impact on patterns of chronic liver disease and cancer.

The introduction of Laboratory testing for anti-HBcore in blood donors

Introduction. The introduction of screening testing for antibodies to the hepatitis B virus nuclear antigen (anti-HBcore) is designed to prevent the procurement of donated blood from individuals with the latent (occult) form of viral hepatitis B, in which surface HBsAg is not identified.

Aim – to evaluate the frequency of anti-HBcore markers’ occurrence in donors under the current regulatory and legal framework.

Materials and methods. This retrospective observational study was conducted with a follow-up period of one year among blood donors of the Blood Center (BC) of the Federal Medical-Biological Agency. The screening study for anti-HBcore in blood donors and its components was selective in accordance with the requirements of Appendix № 4 of Order № 1166n of October 28, 2020 of the Ministry of Health of Russia.

Results. During the study period, the BC was visited by 17,180 donors who donated blood and its components 35,840 times. There were 181 anti-HBcore tests (0.5 % of all blood samples) in 178 unique donors of blood and blood components (1.03 % of all donors). There were 14 positive, 2 questionable and 166 negative results on anti-HBcore tests. The probability of finding a positive result depending on the conditions was 9 % (7.3–14.7 %). There were no statistically significant differences in the detection of anti-HBcore in primary versus regular donors (OR = 2.539; 95% CI: 0.7321–8; p = 0.13), as well as for male donors compared with female donors (OR = 2.448; 95% CI: 0.7141–11.11; p = 0.17). 86.7 % of donors with a positive test for anti-HBcore previously had no signs of viral hepatitis B disease, the presence of questionable HBsAg was not detected, i. e. these cases may be associated with an occult form. Donors who did not previously have questionable results for various bloodborne infections during their donor career had a slightly higher probability of detecting a positive anti-HBcore test compared to donors who previously had these questionable results (OR = 1.24; 95% CI”: 0.42–3.69; p = 0.69). During the period of the donor career, 233 donations of blood and its components were made by donors with a positive result for anti-HBcore, 468 units of donor components were received, of which 365 units were given to medical institutions.

Conclusion. The probability of obtaining a positive test for anti-HBcore in the current regulatory environment is random and does not depend on the results of other infectious markers testing. It is recommended to perform anti-HBcore testing with each donation of blood and blood components.

Compartmentalisation of Hepatitis B virus X gene evolution in hepatocellular carcinoma microenvironment and the genotype-phenotype correlation of tumorigenicity in HBV-related patients with hepatocellular carcinoma

Hepatitis B virus (HBV) exists as quasispecies (QS). However, the evolutionary characteristics of haplotypes of HBV X gene in the hepatocellular carcinoma (HCC) microenvironment remain unclear. Mutations across X gene are essential for the tumorigenicity of HBV X protein (HBx). However, the functional phenotypes of many mutant HBx remain unknown. This study aims to compare the characteristics of X gene evolution between tumour and non-tumour tissues in HCC patients and investigate the tumorigenic phenotype of HBx harbouring mutation T81P/S101P/L123S. This study included 24 HCC patients. Molecular cloning of X gene was performed to analyse characteristics of haplotypes in liver tissues. HCC cell lines stably expressing wild-type or mutant HBx and subcutaneous tumour xenograft mouse model were used to assess HBx-T81P/S101P/L123S tumorigenicity. The mean heterogeneity of HBV QS across X gene in tumour tissues was lower than that in non-tumour tissues. A location bias was observed in X gene clones with genotype C or D in tumour tissues compared to those with genotype B. Mutations in genotype-C or - D clones were mainly clustered in the dimerization region and aa110-aa140 within the transactivation region. A novel mutation combination at residues 81, 101 and 123 was identified in tumour tissues. Further, HBx-T81P/S101P/L123S promotes cell proliferation and increases genomic instability, which was mediated by MYC. This study elucidates the compartmentalized evolution patterns of HBV X gene between intra tumour and non-tumour tissues in HCC patients and provides a new mechanism underlying HBV-driven hepatocarcinogenesis, suggesting a potential viral marker for monitoring HCC.

Whole genome analysis of hepatitis B virus before and during long-term therapy in chronic infected patients: Molecular characterization, impact on treatment and liver disease progression

Hepatitis B virus (HBV) infection remains a serious public health concern worldwide despite the availability of an efficient vaccine and the major improvements in antiviral treatments. The aim of the present study is to analyze the mutational profile of the HBV whole genome in ETV non-responder chronic HBV patients, in order to investigate antiviral drug resistance, immune escape, and liver disease progression to Liver Cirrhosis (LC) or Hepatocellular Carcinoma (HCC). Blood samples were collected from five chronic hepatitis B patients. For each patient, two plasma samples were collected, before and during the treatment. Whole genome sequencing was performed using Sanger technology. Phylogenetic analysis comparing the studied sequences with reference ones was used for genotyping. The mutational profile was analyzed by comparison with the reference sequence M32138. Genotyping showed that the studied strains belong to subgenotypes D1, D7, and D8. The mutational analysis showed high genetic variability. In the RT region of the polymerase gene, 28 amino acid (aa) mutations were detected. The most significant mutations were the pattern rtL180M + rtS202G + rtM204V, which confer treatment resistance. In the S gene, 35 mutations were detected namely sP120T, sT126S, sG130R, sY134F, sS193L, sI195M, and sL216stop were previously described to lead to vaccine, immunotherapy, and/or diagnosis escape. In the C gene, 34 mutations were found. In particular, cG1764A, cC1766G/T, cT1768A, and cC1773T in the BCP; cG1896A and cG1899A in the precore region and cT12S, cE64D, cA80T, and cP130Q in the core region were associated with disease progression to LC and/or HCC. Other mutations were associated with viral replication increase including cT1753V, cG1764A/T, cC1766G/T, cT1768A, and cC1788G in the BCP as well as cG1896A and cG1899A in the precore region. In the X gene, 30 aa substitutions were detected, of which substitutions xT36D, xP46S, xA47T, xI88F, xA102V, xI127T, xK130M, xV131I, and xF132Y were previously described to lead to LC and/or HCC disease progression. In conclusion, our results show high genetic variability in the long-term treatment of chronic HBV patients causing several effects. This could contribute to guiding national efforts to optimize relevant HBV treatment management in order to achieve the global hepatitis elimination goal by 2030.

[Modern views on the role of X gene of the hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus) in the pathogenesis of the infection it causes]

The review presents information on the role of hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus) (HBV) X gene and the protein it encodes (X protein) in the pathogenesis of viral hepatitis B. The evolution of HBV from primordial to the modern version of hepadnaviruses (Hepadnaviridae), is outlined as a process that began about 407 million years ago and continues to the present. The results of scientific works of foreign researchers on the variety of the influence of X protein on the infectious process and its role in the mechanisms of carcinogenesis are summarized. The differences in the effect of the X protein on the course of the disease in patients of different ethnic groups with regard to HBV genotypes are described. The significance of determining the genetic variability of X gene as a fundamental characteristic of the virus that has significance for the assessment of risks of hepatocellular carcinoma (HCC) spread among the population of the Russian Federation is discussed.

Genetic diversity in enhancer II region of HBV genotype D and its association with advanced liver diseases

Background

Hepatitis B Virus (HBV) is one of the most common human infectious agents, and the mutations in its genome may cause chronic hepatitis (CH), liver cirrhosis (LC), and hepatocellular carcinoma (HCC). This study was designed to characterize the enhancer-II (Enh-II) region of X gene in HBV positive patients to assess the association of such mutations with CH, LC, and HCC.

Methods

HBV positive samples (N = 200) with patients’ demographic and clinical data were collected from different regions of Khyber Pakhtunkhwa (KP), Pakistan. The Enh-II region of the HBx gene was sequenced and zanalyzed for polymorphism associated with advanced liver disease. Univariate and logistic regression analyses were performed to evaluate potent mutations associated with a risk for LC and HCC.

Results

HBV Enh-II region sequences analysis revealed 25 different mutations. The highest frequency of mutations S101F (62.2%), A102V/R/G/I (56.25%), M103L/A (68.75%)were found in HCC, followed in LC and CH patients as 57.1%, 42.8%, 28.52% 16%, 15.2% and 18.4% respectively. H94 deletion in the α-box of the Enh-II region, associated with a high risk of HCC was found in half of the HCC patients. This deletion was present in 28.5% of LC and 6.5% of CH patients. Importantly, the high frequency of some notable mutations such as E109A/Y, A110S/K, Y111D/E, and F112L was first time reported in the entire study population. The frequencies of these mutations were high in HCC (43.75%, 37.5%, 50% and 43.75% respectively) as compared to LC (14.28%, 14.28%, 28.2% and 42.8%) and CH patients (12.8%, 15.2%, 16.8% and 16% respectively).

Conclusion

Mutations associated with LC and HCC are prevalent in the Enh-II region in Pakistani HBV isolates. The mutations found are alarming in CH patients as these may progress to LC and HCC in a large number of patients.

Blood-Based Biomarkers in Hepatitis B Virus-Related Hepatocellular Carcinoma, Including the Viral Genome and Glycosylated Proteins

Hepatitis B virus (HBV) infection is a major risk factor for hepatocellular carcinoma (HCC) development and is a global public health issue. High performance biomarkers can aid the early detection of HCC development in HBV-infected individuals. In addition, advances in the understanding of the pathogenesis of HBV infection and in clinical laboratory techniques have enabled the establishment of disease-specific tests, prediction of the progression of liver diseases, including HCC, and auxiliary diagnosis of HCC, using blood-based methods instead of biopsies of liver or HCC tissues. Viral factors such as the HBV genotype, HBV genetic mutations, HBV DNA, and HBV-related antigens, as well as host factors, such as tumor-associated proteins and post-translational modifications, especially glycosylated proteins, can be blood-based, disease-specific biomarkers for HCC development in HBV-infected patients. In this review, we describe the clinical applications of viral biomarkers, including the HBV genome and glycosylated proteins, for patients at a risk of HBV-related HCC, based on their molecular mechanisms. In addition, we introduce promising biomarker candidates for practical use, including colony stimulating factor 1 receptor (CSF1R), extracellular vesicles, and cell-free, circulating tumor DNA. The clinical use of such surrogate markers may lead to a better understanding of the risk of disease progression and early detection of HCC in HBV-infected patients, thereby improving their prognosis.

Paradoxical HBsAg and anti-HBs coexistence among Chronic HBV Infections: Causes and Consequences

Hepatitis B surface antigen (HBsAg) and Hepatitis B surface antibody (anti-HBs) were reported simultaneously among Hepatitis B virus (HBV) infections. HBsAg is a specific indicator of acute or chronic HBV infections, while anti-HBs is a protective antibody reflecting the recovery and immunity of hosts. HBsAg and anti-HBs coexist during seroconversion and then form immune complex, which is rare detected in clinical cases. However, with the promotion of vaccination and the application of various antiviral drugs, along with the rapid development of medical technology, the coexistence of HBsAg and anti-HBs has become more prevalent. Mutations in the viral genomes, immune status and genetic factors of hosts may contribute to the coexistence. Novel HBsAg assays, with higher sensitivity and ability to detect mutations or immune complexes, can also yield HBsAg/anti-HBs coexistence. The discovery of coexistence has shattered the idea of traditional serological patterns and raised questions about the effectiveness of vaccines. Worth noting is that HBsAg/anti-HBs double positivity is strongly associated with progressive liver diseases, especially hepatocellular carcinoma. In conclusion, viral mutations, host factors, and methodology impacts can all lead to the coexistence of HBsAg and anti-HBs. This coexistence is not an indicator of improvement, as an increased risk of adverse clinical outcomes still exists.

Sophisticated viral quasispecies with a genotype-related pattern of mutations in the hepatitis B X gene of HBeAg-ve chronically infected patients

Patients with HBeAg-negative chronic infection (CI) have not been extensively studied because of low viremia. The HBx protein, encoded by HBX, has a key role in viral replication. Here, we analyzed the viral quasispecies at the 5' end of HBX in CI patients and compared it with that of patients in other clinical stages. Fifty-eight HBeAg-negative patients were included: 16 CI, 19 chronic hepatitis B, 16 hepatocellular carcinoma and 6 liver cirrhosis. Quasispecies complexity and conservation were determined in the region between nucleotides 1255 and 1611. Amino acid changes detected were tested in vitro. CI patients showed higher complexity in terms of mutation frequency and nucleotide diversity and higher quasispecies conservation (p < 0.05). A genotype D-specific pattern of mutations (A12S/P33S/P46S/T36D-G) was identified in CI (median frequency, 81.7%), which determined a reduction in HBV DNA release of up to 1.5 log in vitro. CI patients showed a more complex and conserved viral quasispecies than the other groups. The genotype-specific pattern of mutations could partially explain the low viremia observed in these patients.

Molecular characterization of hepatitis B virus reveals circulation of multiple subgenotypes of genotype D with clinically important mutations in central India

PURPOSE

Hepatitis B virus (HBV) is one of the leading causes of morbidity and mortality across the globe. The pathogenesis, clinical outcomes, disease progression and response to antiviral treatment of HBV depend on infecting genotypes and mutations across HBV genome. There is a lack of such information from central India. The present study was planned to identify genotype/subgenotype and epidemiologically important mutation in HBV circulating in the area.

METHODS

Samples positive for HBsAg by ELISA from 2012 to 2016 were included and analysed in this retrospective study. The amplification of partial S gene (n = 25) and full genome (n = 10) was carried out to determine the genotype/subgenotype and genome wide mutations of HBV. The sequencing data was analysed using bioinformatics tools.

RESULTS

All 25 sequences belonged to genotype D; subgenotypes D1, D2, D3 and D5 with dominance of D1 were detected in the study subjects. Mutational profiling revealed the presence of nucleotide substitutions in promoter/regulatory/precore region associated with liver disease progressions. The amino acid (aa) changes associated with vaccine escape, immune escape, antiviral resistance and progression to liver cirrhosis (LC) or hepatocellular carcinoma (HCC) were detected.

CONCLUSIONS

This maiden molecular study on HBV from central India indicates that the genotype D with subgenotypes D1, D2, D3 and D5 harbouring mutations of clinical and epidemiological importance are in circulation. This study will serve as a baseline for future. Studies with larger sample size may aid in identifying the circulation of more genotypes.

Downregulation of GSK3β and Upregulation of URG7 in Hepatitis B-Related Hepatocellular Carcinoma

: Hepatitis B virus (HBV) is the leading cause of hepatocellular carcinoma (HCC). The exact molecular contributors to the development of HBV-related HCC are not yet completely understood. Recent studies demonstrated that the deregulation of the Wnt pathway is highly associated with the development of HCC. Besides, HBV is known to have roles in the deregulation of this pathway. The present study evaluated the molecular aspects of the Wnt pathway in HBV-related HCC in liver tissue samples. Viral characterization was done by identifying the HBx mutations and the assessment of intrahepatic viral load. The expression of Wnt pathway genes was assessed using real-time PCR and methylation-specific PCR. The intrahepatic viral load was significantly higher in tumor samples than in normal tissues (P = 0.0008). Aberrant expression was observed in Wnt-1, Wnt-7a, FZD2, FZD7, β-catenin, URG7, c-Myc, SFRP5, and GSK3β, among which Wnt1, FZD2, SFRP5, Gsk3β, and URG7 were associated with HBV. HBx mutations at positions I88, L116, and I127 + F132 were associated with the decreased expression of GSK3β and overexpression of URG7 and Wnt1. Alterations in the expression level of β-catenin, as well as some mutants of HBx, were correlated with the level of c-Myc. HBV-related HCC seems to be mostly coordinated with epigenetic behaviors of HBx, such a multi-functional peptide with suppressing/trans-activating functions.

A Systematic Review of the Current Hepatitis B Viral Infection and Hepatocellular Carcinoma Situation in Mediterranean Countries

Viral hepatitis B is a global public health problem affecting nearly two billion subjects; 3.3% of whom are from the WHO (World Health Organization) Eastern Mediterranean Region (EMRO). It induces both acute and chronic hepatic disorders with subsequent liver cirrhosis and hepatocellular carcinoma (HCC) in a considerable percentage of patients based on the age of exposure. In this review, hepatitis B virus (HBV) and HCC prevalence, distribution and prevalence of different genotypes, and male/female infection frequencies in relation to the vaccination status in the Mediterranean countries were reported. Study Design. This systematic review describes the prevalence of hepatitis B infection, genotype distribution of hepatitis B virus, and prevalence and incidence of hepatocellular carcinoma in Mediterranean countries belonging to three different continents: Southern Europe (Spain, France, Italy, Croatia, and Greece), North Africa (Morocco, Algeria, Tunisia, Libya, and Egypt), and the Near East region (Syria, Lebanon, Turkey, Israel, and Palestine). We tried to collect new data from electronic databases: PubMed, ScienceDirect, ResearchGate, Google Scholar, and public health reports between 1980 and 2019. For each publication, we recorded reference, publication year, study characteristics (date, locations, sample size, and study population), and participant characteristics (population group, year, age, and sex). No language limitation was imposed, and articles or reports from non-peer-reviewed sources were not considered for this analysis. The main keywords were HBV prevalence, hepatitis B infection, HBV genotype, and HCC. Inclusion and Exclusion Criteria. Healthy population-based studies included the following sample populations: (i) voluntary blood donors, (ii) pregnant women, (iii) community studies, (iv) hemodialysis patients, (v) hospitalized patients, (vi) healthcare workers, (vii) sex workers, (viii) drug abusers, and (ix) prisoners. We excluded studies from the following special groups who were assumed to be at a special high risk: patients from sexually transmitted disease clinics and thalassemia clinics and professional or paid blood donors.

Association between host TNF-α, TGF-β1, p53 polymorphisms, HBV X gene mutation, HBV viral load and the progression of HBV-associated chronic liver disease in Indonesian patients

In developing countries, including Indonesia, there is a high mortality rate associated with the progression of hepatitis B virus (HBV)-associated chronic liver disease (CLD). The pathogenesis of HBV infection is influenced by viral and host factors. To determine potential associations between these factors, host single nucleotide polymorphisms (SNPs) on TNF-α, TGF-β1 and p53, HBV X gene mutation and HBV viral load were investigated in patients with HBV-associated CLD in Surabaya, Indonesia. Sera were collected from 87 CLD patients with HBV infection. TNF-α, TGF-β1 and p53 SNPs were genotyped by PCR restriction fragment length polymorphism. The HBV X gene was sequenced and compared with reference strains to determine mutations and the viral load was measured using reverse transcription-quantitative PCR. In Indonesian patients, no association between TNF-α, TGF-β1 and p53 SNPs and CLD or X gene mutation were identified. A total of 23% (20/87) of samples had HBV X gene mutations, including ten substitution types, one deletion and one insertion. Multinomial regression analysis revealed that the K130M/V131I mutations were correlated with CLD progression (OR, 7.629; 95% CI, 1.578-36.884). Significant differences in viral load were found in HBV-infected patients who had X gene mutations, such as R87W/G, I127L/T/N/S and K130M/V131I mutations (P<0.05). The presence of K130M and V131I mutations may be predictive for the progression of HBV-associated CLD in Indonesia.

Hepatitis B virus X protein: The X factor in chronic hepatitis B virus disease progression

Introduction

Hepatitis B virus (HBV) is the most common aetiological factor causing hepatocellular carcinoma (HCC). HBx gene plays an enigmatic role in HBV-related HCC. In this study we have analysed amino acid substitutions in HBx from HBV-infected individuals of different clinical stages.

Materials and Methods

HBV-infected individuals (n = 93) were recruited in the study. DNA was extracted from plasma, amplified, and DNA sequencing was performed using specific primers targeting HBx gene (540 bp).

Results

Among the study participants, 57% had chronic HBV infection, 30% had chronic liver disease (CLD) and 13% had HBV related HCC. Genotypes such as D1, D2, D3, A1, C2 and B2 were identified of which genotype D2 was predominant (78%). HBxC-terminal deletion was observed in four hepatitis B e antigen (HBeAg) negative participants with CLD. The frequency of aminoacid substitution in proapoptotic domain was higher in HBeAg negative participants including I127V (34%), K130M (34%), V131I (40%). The frequency of double mutation (K130M+V131I) and triple mutation (I127V+K130M+V131I) were found to be higher (32% and 36%) in HBeAg negative participants. Also, we identified L5M substitution (4.3%) in HBeAg positive participants with advanced liver disease.

Conclusion

In HBx gene, aminoacid substitutions at positions 127, 130, 131 are associated with poor expression of HBeAg. We suggest screening for HBx aminoacid substitutions especially in patients with HBeAg negative chronic HBV infection to predict the clinical outcome and enable early treatment to prevent disease progression.

Hepatitis B Virus Molecular Epidemiology, Host-Virus Interaction, Coinfection, and Laboratory Diagnosis in the MENA Region: An Update

Hepatitis B virus (HBV) is an enveloped partial double-stranded DNA virus that can cause acute and chronic hepatitis. According to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), 257 million people are living with HBV. Moreover, 20,900 acute hepatitis B cases were reported in 2016. Hepatitis B is highly prevalent in the African, Western Pacific, Eastern Mediterranean, South-East Asia, and European regions, respectively. Due to the high mutational rate of HBV and lack of reverse transcriptase proofreading activity, ten different genotypes with different geographical distributions have been identified. HBV pathogenesis and severity of infection depend on several host and viral factors, particularly, the genetic variability of both the host and virus. Although HBV infection is a global health concern, there is a lack of adequate studies and reports in the Middle East and North Africa (MENA) region. Here, we provide a review on HBV epidemiology, pathogenesis, host-pathogen interactions, coinfection with selected viruses, and laboratory diagnosis, focusing on studies conducted in the MENA region to determine the current situation of the HBV infection and outline the future study areas.

The novel HBx mutation F30V correlates with hepatocellular carcinoma in vivo, reduces hepatitis B virus replicative efficiency and enhances anti-apoptotic activity of HBx N terminus in vitro

OBJECTIVE

We aimed to investigate HBx genetic elements correlated with hepatitis B virus (HBV) -related hepatocellular carcinoma (HCC) and their impact on (a) HBV replicative efficiency, (b) HBx binding to circular covalently closed DNA (cccDNA), (c) apoptosis and cell-cycle progression, and (d) HBx structural stability.

METHODS

This study included 123 individuals chronically infected with HBV: 27 with HCC (77.9% (21/27) genotype D; 22.1% (6/27) genotype A) and 96 without HCC (75% (72/96) genotype D; 25.0% (24/96) genotype A). HepG2 cells were transfected by wild-type or mutated linear HBV genome to assess pre-genomic RNA (pgRNA) and core-associated HBV-DNA levels, HBx-binding onto cccDNA by chromatin immunoprecipitation-based quantitative assay, and rate of apoptosis and cell-cycle progression by cytofluorimetry.

RESULTS

F30V was the only HBx mutation correlated with HCC (18.5% (5/27) in HCC patients versus 1.0% (1/96) in non-HCC patients, p 0.002); a result confirmed by multivariate analysis. In vitro, F30V determined a 40% and 60% reduction in pgRNA and core-associated HBV-DNA compared with wild-type (p <0.05), in parallel with a significant decrease of HBx binding to cccDNA and decreased HBx stability. F30V also decreased the percentage of apoptotic cells compared with wild-type (14.8 ± 6.8% versus 19.1 ± 10.1%, p <0.01, without affecting cell-cycle progression) and increased the probability of HBx-Ser-31 being phosphorylated by PI3K-Akt kinase (known to promote anti-apoptotic activity).

CONCLUSIONS

F30V was closely correlated with HBV-induced HCC in vivo, reduced HBV replicative efficiency by affecting HBx-binding to cccDNA and increased anti-apoptotic HBx activity in vitro. This suggests that F30V (although hampering HBV's replicative capacity) may promote hepatocyte survival, so potentially allowing persistent production of viral progeny and initiating HBV-driven hepatocarcinogenesis. Investigation of viral genetic markers associated with HCC is crucial to identify those patients at higher risk of HCC, who hence deserve intensive liver monitoring and/or early anti-HBV therapy.

Impact of wild-type and carboxyl-terminal truncated hepatitis B virus X on hepatocyte proliferation

AIM

To construct lentiviral vectors expressing human wild-type HBx (wt-HBx) and truncated HBx (tHBx^Δ35) and study the effect of wt-HBx and tHBx^Δ35 on the proliferation and apoptosis of normal liver cell lines.

METHODS

Lentiviral vectors TOPO3.1-wt-HBx and TOPO3.1-tHBx^Δ35 were constructed and transfected into 293T cells with three packaging plasmids. The supernatants were collected to infect LO2 and MIHA cells, respectively. The expression of wt-HBx and tHBx^Δ35 was detected by fluorescence microscopy and western blot analysis. The effect of HBx and tHBx^Δ35 on the proliferation, cell cycle, and apoptosis was analyzed by cell counting, MTS, and flow cytometry, respectively.

RESULTS

The recombinant lentiviral vectors were successfully constructed. The proliferation of liver cells infected with tHBx^Δ35 was significantly increased, compared with HBx or CTRL infected cells, while the proliferation of liver cells infected with HBx was decreased compared with tHBx^Δ35 or CTRL infected cells (P < 0.05). tHBx^Δ35 improved the number of cells in S phase, while HBx induced G0/G1-S cell cycle arrest. The effect of tHBx^Δ35 or HBx on apoptosis was mild.

CONCLUSION

HBx can inhibit the proliferation of hepatocytes, while tHBx^Δ35 can improve the proliferation of liver cells.