ABSTRACT
BACKGROUND: Little is known about molecular characteristics of HBV strains circulating in Algeria and there are few data regarding HDV infection. OBJECTIVES: The aim of this study is to describe the genetic diversity of HBV and HDV strains existing in Algeria and to determine the seroprevalence of HDV infection. STUDY DESIGN: Plasma samples from 134 patients were analyzed by enzyme immunoassay method for HBV and HDV serological markers. Genotyping of HBV and HDV strains were performed using direct sequencing followed by phylogenetic analyses of the PreS1 and R0 region of the HBV and HDV genome respectively. RESULTS: The PreS1 gene was successfully amplified in 119 patients (82 males and 37 females). Phylogenetic analysis of HBV strains revealed the presence of genotypes D (86.5%) and A2 (11.76%). The subgenotypes D are distributed as follows: HBV/D7 (43.5%), HBV/D3 (24.75%), HBV/D1 (16.8%) and HBV/D2 (14.85%). A recombinant between genotypes A, E and D was found. The seroprevalence of HDV infection among HBV carriers was less than 5.35%. Only one isolate of HDV genotype 1 was identified. CONCLUSIONS: Our data indicate the predominance of HBV subgenotype D7 and a low prevalence of HDV infection.
Subject(s)
Genotype , Hepatitis B virus/classification , Hepatitis B/virology , Hepatitis D/epidemiology , Hepatitis D/virology , Hepatitis Delta Virus/classification , Adolescent , Adult , Aged , Algeria/epidemiology , Child , Enzyme-Linked Immunosorbent Assay , Female , Genotyping Techniques , Hepatitis Antibodies/blood , Hepatitis B virus/genetics , Hepatitis B virus/isolation & purification , Hepatitis Delta Virus/genetics , Hepatitis Delta Virus/isolation & purification , Humans , Male , Middle Aged , Molecular Epidemiology , Sequence Analysis, DNA , Seroepidemiologic Studies , Young AdultABSTRACT
BACKGROUND & AIMS: Hepatitis B virus (HBV) RNA can undergo alternative splicing, but the relevance of this post-transcriptional regulation remains elusive. The mechanism of HBV alternative splicing regulation and its impact on liver pathogenesis were investigated. METHODS: HBV RNA-interacting proteins were identified by RNA pull-down, combined with mass spectrometry analysis. HBV splicing regulation was investigated in chemically and surgically induced liver damage, in whole HBV genome transgenic mice and in hepatoma cells. Viral and endogenous gene expression were quantified by quantitative reverse transcription polymerase chain reaction, Western blot and enzyme-linked immunosorbent assay. Resident liver immune cells were studied by fluorescence-activated cell sorting. RESULTS: HBV pregenomic RNA-interacting proteins were identified and 15% were directly related to the splicing machinery. Expression of these splicing factors was modulated in HBV transgenic mice with liver injuries and contributed to an increase of the HBV spliced RNA encoding for HBV splicing-generated protein (HBSP). HBSP transgenic mice with chemically induced liver fibrosis exhibited attenuated hepatic damage. The protective effect of HBSP resulted from a decrease of inflammatory monocyte/macrophage recruitment through downregulation of C-C motif chemokine ligand 2 (CCL2) expression in hepatocytes. In human hepatoma cells, the ability of HBSP to control CCL2 expression was confirmed and maintained in a whole HBV context. Finally, viral spliced RNA detection related to a decrease of CCL2 expression in the livers of HBV chronic carriers underscored this mechanism. CONCLUSION: The microenvironment, modified by liver injury, increased HBSP RNA expression through splicing factor regulation, which in turn controlled hepatocyte chemokine synthesis. This feedback mechanism provides a novel insight into liver immunopathogenesis during HBV infection. Lay summary: Hepatitis B virus persists for decades in the liver of chronically infected patients. Immune escape is one of the main mechanisms developed by this virus to survive. Our study highlights how the crosstalk between virus and liver infected cells may contribute to this immune escape.
Subject(s)
Alternative Splicing , Hepatitis B virus/genetics , Hepatitis B virus/immunology , Host-Pathogen Interactions/genetics , Host-Pathogen Interactions/immunology , Alternative Splicing/immunology , Animals , Chemokine CCL2/metabolism , Hepatitis B virus/pathogenicity , Hepatitis B, Chronic/immunology , Hepatitis B, Chronic/virology , Humans , Immune Evasion/genetics , Liver/immunology , Liver/injuries , Liver/virology , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , RNA Splicing Factors/metabolism , RNA, Viral/genetics , RNA, Viral/metabolismABSTRACT
The epidemic history of HCV genotype 5a is poorly documented in France, where its prevalence is very low, except in a small central area, where it accounts for 14.2% of chronic hepatitis C cases. A Bayesian coalescent phylogenetic investigation based on the E1 envelope gene and a non-structural genomic segment (NS3/4) was carried out to trace the origin of this epidemic using a large sample of genotype 5a isolates collected throughout France. The dates of documented transmissions by blood transfusion were used to calibrate five nodes in the phylogeny. The results of the E1 gene analysis showed that the best-fitting population dynamic model was the expansion growth model under a relaxed molecular clock. The rate of nucleotide substitutions and time to the most recent common ancestors (tMRCA) of genotype 5a isolates were estimated. The divergence of all the French HCV genotype 5a strains included in this study was dated to 1939 [95% HPD: 1921-1956], and the tMRCA of isolates from central France was dated to 1954 [1942-1967], which is in agreement with epidemiological data. NS3/4 analysis provided similar estimates with strongly overlapping HPD values. Phylodynamic analyses give a plausible reconstruction of the evolutionary history of HCV genotype 5a in France, suggesting the concomitant roles of transfusion, iatrogenic route and intra-familial transmission in viral diffusion.