Project description:Small, non-coding RNAs control gene expression post-transcriptionally and play important roles in virus-host interactions. Within the liver, the microRNA (miRNA) miR-122 is essential for replication of hepatitis C virus (HCV), while repression of miR-148a by hepatitis B virus (HBV) may enhance tumorigenesis. Despite their importance to the outcome of these infections, few previous studies have described unbiased profiling of small RNAs in the liver during chronic viral hepatitis. Here, we sequenced small (14-40 nts) RNAs in liver from subjects with chronic hepatitis B and C. We found that small RNAs derived from tRNAs, specifically 5’ tRNA-halves (“5’ tRHs”, ~31-34 nts), are abundant in liver and significantly increased during chronic viral infection in humans and also chimpanzees. In most infected livers, 5’ tRH abundance exceeded that of miRNAs. In contrast, in hepatocellular carcinoma (HCC) tissue from these subjects, tRH abundance was reduced concomitant with decreased expression of the tRNA-cleaving ribonuclease, angiogenin. Although tRHs have been identified in mice, our results show they are abundantly expressed in human tissue, increased in chronic viral infection, and decreased in liver cancer. Our findings highlight the potential biological and clinical relevance of these small non-coding RNAs. Small RNA-seq of liver samples from control subjects (n=4), subjects with chronic hepatitis B (n=4) and hepatitis B associated hepatocellular carcinoma (n=4, 3 out of 4 matched with non-tumor tissue) and subjects with chronic hepatitis C (n=4) and tissue from hepatocellular carcinoma of the same patients. Also, small RNA-seq of AGO2 and IgG pulldown in FT3-7 cells. Sequenced AGO2 pulldown (n=3), IgG pulldown (n=2) and total small RNA from FT3-7 cells (n=3). This dataset is part of the TransQST collection.
Project description:Small, non-coding RNAs control gene expression post-transcriptionally and play important roles in virus-host interactions. Within the liver, the microRNA (miRNA) miR-122 is essential for replication of hepatitis C virus (HCV), while repression of miR-148a by hepatitis B virus (HBV) may enhance tumorigenesis. Despite their importance to the outcome of these infections, few previous studies have described unbiased profiling of small RNAs in the liver during chronic viral hepatitis. Here, we sequenced small (14-40 nts) RNAs in liver from subjects with chronic hepatitis B and C. We found that small RNAs derived from tRNAs, specifically 5’ tRNA-halves (“5’ tRHs”, ~31-34 nts), are abundant in liver and significantly increased during chronic viral infection in humans and also chimpanzees. In most infected livers, 5’ tRH abundance exceeded that of miRNAs. In contrast, in hepatocellular carcinoma (HCC) tissue from these subjects, tRH abundance was reduced concomitant with decreased expression of the tRNA-cleaving ribonuclease, angiogenin. Although tRHs have been identified in mice, our results show they are abundantly expressed in human tissue, increased in chronic viral infection, and decreased in liver cancer. Our findings highlight the potential biological and clinical relevance of these small non-coding RNAs.
Project description:Hepatitis A virus (HAV) is a hepatotropic human picornavirus that has been associated only with acute infection. Its pathogenesis is not well understood since there have been few recent studies in animal models using modern methodologies. We characterized HAV infections in three chimpanzees, quantifying viral RNA by qRT-PCR and examining critical aspects of the innate immune response including intrahepatic interferon-stimulated gene expression. We compared these infection profiles with similar studies of chimpanzees infected with hepatitis C virus (HCV), a hepatotropic flavivirus that frequently causes persistent infection. Surprisingly, HAV-infected animals exhibited very limited induction of type I interferon-stimulated genes in the liver compared to chimpanzees with acute resolving HCV infection, despite similar levels of viremia and 100-fold greater quantities of viral RNA in the liver. Minimal ISG15 and IFIT1 responses peaked 1-2 weeks after HAV challenge, then subsided despite continuing high hepatic viral loads. An acute inflammatory response at 3-4 weeks correlated with the appearance of virus-specific antibodies, and both apoptosis and proliferation of hepatocytes. Despite this, HAV RNA persisted in the liver for months, remaining present long after its clearance from serum and feces and revealing dramatic differences in the kinetics of clearance in the three compartments. Viral RNA was detected in the liver for significantly longer (35 to >48 weeks) than HCV RNA in animals with acute resolving HCV infection (10-20 weeks). Collectively, these findings suggest that early HAV infection is far stealthier than HCV infection and represents a distinctly different paradigm in viral-host interactions within the liver. Chimpanzee liver was biopsied during an acute HAV infection. Chimp 1 and 2 had two baseline samples. Chimp 3 used the baselines from chimps 1 and 2. Chimp 1 had 8 samples during the HAV acute infection. Chimp 2 had 9 samples during the HAV acute infection. Chimp 3 had 4 samples during the HAV acute infection.
Project description:Philip Aston. A New Model for the Dynamics of Hepatitis C Infection: Derivation, Analysis and Implications. Viruses 10, 4 (2018).
We review various existing models of hepatitis C virus (HCV) infection and show that there are inconsistencies between the models and known behaviour of the infection. A new model for HCV infection is proposed, based on various dynamical processes that occur during the infection that are described in the literature. This new model is analysed, and three steady state branches of solutions are found when there is no stem cell generation of hepatocytes. Unusually, the branch of infected solutions that connects the uninfected branch and the pure infection branch can be found analytically and always includes a limit point, subject to a few conditions on the parameters. When the action of stem cells is included, the bifurcation between the pure infection and infected branches unfolds, leaving a single branch of infected solutions. It is shown that this model can generate various viral load profiles that have been described in the literature, which is confirmed by fitting the model to four viral load datasets. Suggestions for possible changes in treatment are made based on the model.
Project description:Hepatitis B virus (HBV) is an enveloped, coated, non-cytopathic and hepatotropic partially double-stranded DNA virus in the family Hepadnaviridae genus Orthohepadnavirus. Despite significant progress in the availability of safe vaccines and antiviral therapies against HBV, it still affects approximately 257 million people worldwide and is responsible for about 887,000 deaths per year around the world [4]. HBV infection, which are associated with acute and chronic liver failure responses to viruses attacked the liver, can result in inactive carrier state, chronic hepatitis, or fulminant hepatitis and put them at high risk to develop advanced liver fibrosis and cirrhosis, and even hepatocellular cancer. Many viral factors, which could affect the disparity of clinical outcomes or disease prognosis during chronic HBV infection, have been reported in previous studies; among them, the viral genotype, as well as HBV mutations ascribing the virus to a certain phenotype, was reported to be the most important factor influencing viral pathogenesis, including the change of host immune recognition, the enhanced virulence with increased HBV replication and the facilitation of cell attachment or penetration.
Project description:Chronic viral hepatitis after infection with hepatotropic viruses like hepatitis B virus (HBV) affects 300 million persons worldwide, which as the result of chronic immune-mediated hepatic inflammation cause liver cirrhosis and cancer being responsible for 800.000 deaths per year3. Chronic viral hepatitis is maintained by failure of the host´s immune response to control viral infection, but the mechanisms for this inability of virus-specific CD8 T cells to eliminate HBV-infected hepatocytes remain unclear. Here, we demonstrate that during persistent experimental infection with hepatotropic viruses and HBV replication in hepatocytes all virus-specific CD8 T cells present in the liver expressed the tissue-residency markers CXCR6 and CD69. However, RNAseq analysis revealed that CXCR6+CD8 T cells during persistent hepatotropic infection were retained in the liver because of antigen-recognition rather than a transcriptional tissue-residency program, in contrast to canonical liver-resident memory CXCR6+CD8 T cells emerging after resolved infection. Whereas during persistent infection with a model virus like lymphocytic choriomeningitis virus with broad tissue and cell tropism exhausted CD8 T cells show graded loss of effector functions, hepatic virus-specific CXCR6+CD8 T cells during persistent infection with hepatotropic viruses were blinded and completely non-responsive to stimulation in absence of a canonical tox exhaustion signature. Rather, in blinded liver CXCR6+CD8 T cells, transcription factor network analysis revealed Crem, the cAMP-responsive-element-modulator, as the only transcription factor discreetly active in CD8 T cells with complete loss of effector function during persistent hepatotropic infection. Similarly, single cell RNA-sequencing of peripheral blood HBcore-specific CD8 T cells from chronic hepatitis B patients also revealed enhanced CREM activity. Notably, knock-out of the inhibitory CREM/ICER gene in T cells failed to rescue protective T cell immunity during persistent infection with hepatotropic viruses pointing towards post-translational mechanisms relevant for enhanced Crem activity and loss of effector function. Indeed, T cell receptor-associated signalling was blocked in blinded antigen-specific CXCR6+CD8 T cells, that in situ during persistent hepatotropic infection were in close proximity to liver sinusoidal endothelial cells producing high amounts of cAMP-inducing prostanoids. Inhibitory cAMP/PKA/CSK activity increased CREM activity and disconnected CXCR6+CD8 T cells from activation signalling through the T cell receptor. Thus, enhanced CREM expression identifies blinded liver CXCR6+CD8 T cells, but loss of effector functions is caused by post-translational prevention of signalling, which identifies novel molecular targets for immune monitoring and immune therapy of chronic hepatitis B.
Project description:Hepatitis A virus (HAV) is a hepatotropic human picornavirus that has been associated only with acute infection. Its pathogenesis is not well understood since there have been few recent studies in animal models using modern methodologies. We characterized HAV infections in three chimpanzees, quantifying viral RNA by qRT-PCR and examining critical aspects of the innate immune response including intrahepatic interferon-stimulated gene expression. We compared these infection profiles with similar studies of chimpanzees infected with hepatitis C virus (HCV), a hepatotropic flavivirus that frequently causes persistent infection. Surprisingly, HAV-infected animals exhibited very limited induction of type I interferon-stimulated genes in the liver compared to chimpanzees with acute resolving HCV infection, despite similar levels of viremia and 100-fold greater quantities of viral RNA in the liver. Minimal ISG15 and IFIT1 responses peaked 1-2 weeks after HAV challenge, then subsided despite continuing high hepatic viral loads. An acute inflammatory response at 3-4 weeks correlated with the appearance of virus-specific antibodies, and both apoptosis and proliferation of hepatocytes. Despite this, HAV RNA persisted in the liver for months, remaining present long after its clearance from serum and feces and revealing dramatic differences in the kinetics of clearance in the three compartments. Viral RNA was detected in the liver for significantly longer (35 to >48 weeks) than HCV RNA in animals with acute resolving HCV infection (10-20 weeks). Collectively, these findings suggest that early HAV infection is far stealthier than HCV infection and represents a distinctly different paradigm in viral-host interactions within the liver.
Project description:Hepatitis C virus (HCV) infection has been successfully managed by anti-viral therapies, however, high prevalence to severe chronic liver disease state including non-alcoholic fatty liver disease (NAFLD) is a problem encountered even after the cure of hepatitis C. Moreover, there is currently no reliable in vitro model capable of investigating host-viral interactions and monitoring the progression of viral hepatitis to chronic liver diseases. Recent organoid technology has been reported for successful infection of HCV, but there is still lack of non-parenchymal cells, which play a crucial role in disease progression. Here, we provided a novel multicellular liver organoid model using co-culture system of macrophages and liver organoids differentiated from the same cell source, human embryonic stem cells. Surprisingly, HCV infection led potent lipid accumulation in liver organoids through regulation of host lipid metabolism, which was further promoted by macrophage co-culture. Lipid enriched condition provided by longterm-treatment with fatty acid accelerated potent HCV amplification and further promotion of inflammation and fibrosis progression. Therefore, our model may be a valuable novel platform recapitulating diverse phenotypes with host-virus intercommunication and inter-cellular interactions and further progressive features of hepatitis C-associated chronic NAFLD progression of patients with HCV.
Project description:Hepatitis C virus (HCV) infection has been successfully managed by anti-viral therapies, however, high prevalence to severe chronic liver disease state including non-alcoholic fatty liver disease (NAFLD) is a problem encountered even after the cure of hepatitis C. Moreover, there is currently no reliable in vitro model capable of investigating host-viral interactions and monitoring the progression of viral hepatitis to chronic liver diseases. Recent organoid technology has been reported for successful infection of HCV, but there is still lack of non-parenchymal cells, which play a crucial role in disease progression. Here, we provided a novel multicellular liver organoid model using co-culture system of macrophages and liver organoids differentiated from the same cell source, human embryonic stem cells. Surprisingly, HCV infection led potent lipid accumulation in liver organoids through regulation of host lipid metabolism, which was further promoted by macrophage co-culture. Lipid enriched condition provided by longterm-treatment with fatty acid accelerated potent HCV amplification and further promotion of inflammation and fibrosis progression. Therefore, our model may be a valuable novel platform recapitulating diverse phenotypes with host-virus intercommunication and inter-cellular interactions and further progressive features of hepatitis C-associated chronic NAFLD progression of patients with HCV.