Project description:RNAseq analysis of liver tissue samples from uninfected (n=5) and HBV-infected (n=5) humanized chimeric liver (uPA/SCID) mice was performed to identify potential new host factors and pathways modulated by HBV infection
Project description:Hepatitis B virus (HBV) infection leads tdevelopment of fatal liver complications. Due to a lack of effective measure to cure HBV infection, complete eradication of HBV is difficult. Thus, novel HBV therapeutic strategies are needed. Host proteins involved in the HBV infection processes are known to be regulated through phosphorylation. System level changes in phospho-signaling pathway in host during infection remains unclear. To this end, phosphoproteome profiling on HBV infected HepG2-NTCP cells was performed.
Project description:HBV-specific CD8 cells are deeply exhausted in chronic hepatitis B and their function can only be partially corrected by modulation of up-regulated inhibitory pathways, suggesting a more complex molecular interplay. With the aim of identifying more suitable molecular targets to correct T cell dysfunction, we compared the transcriptome profile of HBV-specific CD8 cells of acute and chronic patients with the reference profile of HBV- and Flu-specific CD8 cells from patients able to resolve HBV infection spontaneously and from healthy subjects. The results indicate that exhausted HBV-specific CD8 cells are deeply impaired at a metabolic and energetic level with a prevalent down-regulation of different key cellular processes centered on an extensive alteration of mitocondrial functions. Mitochondrial modulation by antioxidant compounds could improve significantly the HBV-specific T cell function with minimal effect on T cells of different specificity. The results identify mitochondria as ideal targets for functional T cell reconstitution strategies to cure HBV infection
Project description:Liver-specific ten-eleven translocation methylcytosine dioxygenases 2 and 3 (Tet2 plus Tet3)-deficient hepatitis B virus (HBV) transgenic mice fail to support viral biosynthesis. The levels of viral transcription and replication intermediates are dramatically reduced. Hepatitis B core antigen (HBcAg) is only observed in a very limited number of pericentral hepatocytes in a pattern that is similar to glutamate-ammonia ligase (Glul), a -catenin target gene. HBV transcript abundance in Tet-deficient mice resembles that observed in wild-type neonatal mice. Furthermore, the RNA levels of several -catenin target genes including Glul, Lhpp, Notun, Oat, Slc1a2 and Tbx3, in Tet-deficient mice was also similar to that observed in wild-type neonatal mice. As HBV transcription is regulated by -catenin, these finding support the suggestion that neonatal Tet-deficiency might limit -catenin target gene expression, limiting viral biosynthesis. Additionally, HBV transgene DNA displays increased 5-methylcytosine (5mC) frequency at CpG sequences consistent with neonatal Tet-deficiency being responsible for decreased developmental viral DNA demethylation mediated by 5mC oxidation to 5-hydroxymethylcytosine (5hmC), a process that might be responsible for the reduction in cellular -catenin target gene expression and viral transcription and replication.
Project description:As IFNs do not directly act on the intracellular HBV viral genome, the intrahepatic microenvironment alteration is postulated to be vital for HBV functional cure, and its characteristics at the termination would be informative. We used scRNA-seq to analyze the intrahepatic immune cell population alliteration after 15-week PEG-IFNα2 treatment.
Project description:We used TraDIS-Xpress to determine the mechanism of action of a novel antimicrobial compound. We found that it inhibits lipid IVA biosynthesis in both Escherichia coli and Salmonella enterica serovar Typhimurium. We also were able to determine mechanisms of synergy with colistin, through ATP biosynthesis and the BasSR signalling system.
Project description:Chronic infection of Hepatitis B virus (HBV) remains a public health problem worldwide. HBV infection relies on the persistence of covalently closed circular DNA (cccDNA) in the nucleus and actively cccDNA transcription. To understand HBV cccDNA transcription regulation at single cell level, we isolated primary human hepatocytes from liver humanized FRG mice infected by one or more (two or three) HBV genotypes, and we quantified transcripts of HBV structural genes in single cells. HBV transcripts were ascribed to the transcription of individual HBV genes by 5’ end sequencing thus avoiding the ambiguity caused by the overlap of viral genome coding at the 3’ ends. Transcripts from different cccDNA in single cells were separated according to the single-nucleotide polymorphism (SNP) among different HBV genotypes. We found that the transcription of HBV follows “all-or-none” pattern in single cells: either all of the individual cccDNA molecules actively transcribe simultaneously, or, none of them generates transcripts of the structural genes. In vitro cell infection assays with recombinant HBV are consistent with the sequencing results of ex vivo samples from natural HBV infection, and also confirm that such a pattern is apparently controlled by the expression of HBx protein. These results strongly support a synchronized transcription model of HBV cccDNA molecules in single hepatocytes, and provide new insight helpful for developing HBV cure strategy.
Project description:HBV transcription and replication increases progressively throughout postnatal liver development with maximal viral biosynthesis occurring at around four weeks of age in the HBV transgenic mouse model of chronic infection. Increasing viral biosynthesis is associated with a corresponding progressive loss of DNA methylation. The loss of DNA methylation is associated with increasing levels of 5-hydroxymethylcytosine (5hmC) residues which correlates with increased liver-enriched pioneer transcription factor Forkhead box protein A (FoxA) RNA levels, a rapid decline in postnatal liver DNA methyltransferase (Dnmt) transcripts and a very modest reduction in Ten-eleven translocation (Tet) methylcytosine dioxygenase expression. These observations are consistent with the suggestion that the balance between active HBV DNA methylation and demethylation is regulated by FoxA recruitment of Tet in the presence of declining Dnmt activity. These changes lead to demethylation of the viral genome during hepatocyte maturation with associated increases in viral biosynthesis. Consequently, manipulation of the relative activities of these two counter-balancing processes might permit the specific silencing of HBV gene expression with the loss of viral biosynthesis and the resolution of chronic HBV infections.
Project description:Background and Aims: Recent identification of intracellular DNA sensing pathways and involvement in numerous diverse disease processes including viral pathogenesis and autoimmunity suggests a role for these processes in liver pathology. The presence of these pathways in the liver and their role in HBV infection is unknown. Methods: In order to characterize the role of DNA sensing pathways in the liver, we utilized in vitro models. Microarray was performed on DNA treated and HBV infected hepatoma primary human hepatocytes. Results: Here we show that HBV infection and foreign DNA results in a significant innate immune response characterized by the production of inflammatory chemokines. The goal of this study is to characterize the changes in gene expression triggered by HBV and foreign DNA in primary human hepatocytes. PHHs were infected with HBV (MO.I = 50) for 40 hours. PHHs were transfected with 1μg/mL of ISD/dsDNA90 for 12 or 24 hours. Three replicates were performed for each condition.
Project description:Macrophages are critical immune cells in inflammatory diseases and their differentiation and function are tightly regulated by epigenetic alterations. H3K79 methylation is an epigenetic modification associated with active gene expression and DOT1L is the only histone methyltransferase for H3K79. Here we determine the role of DOT1L in macrophages by applying a selective DOT1L inhibitor in mouse and human macrophages and using myeloid-specific Dot1l deficient mice. We found that DOT1L directly regulates macrophage function by controlling lipid biosynthesis gene programs including central lipid regulators like sterol regulatory element-binding proteins SREBP1 and SREBP2. DOT1L inhibition also leads to macrophage hyperactivation which is associated with disrupted SREBP pathways. In vivo, myeloid Dot1l deficiency reduces atherosclerotic plaque stability and increases the activation of inflammatory plaque macrophages. Our data show that DOT1L is a crucial regulator of macrophage inflammatory responses and lipid regulatory pathways and suggests a high relevance of H3K79 methylation in inflammatory disease.