Project description:Equine hepacivirus (EqHV) is phylogenetically the closest relative of hepatitis C virus (HCV) and shares genome organization, hepatotropism, transient or persistent infection outcome, and the ability to cause hepatitis. Thus, EqHV studies are important to understand equine liver disease, and further as an outbred surrogate animal model for HCV pathogenesis and protective immune responses. Here, we aimed to characterize the course of EqHV infection and associated protective immune responses. Approach & Results: Seven horses were experimentally inoculated with EqHV, monitored for 6 months, and rechallenged with the same, and subsequently a heterologous EqHV. Clearance was the primary outcome (6 of 7) and was associated with subclinical hepatitis characterized by lymphocytic infiltrate and individual hepatocyte necrosis. Seroconversion was delayed and antibody titers waned slowly. Clearance of primary infection conferred non-sterilizing immunity resulting in shortened duration of viremia after rechallenge. Peripheral blood mononuclear cell responses in horses were minimal, although EqHV specific T cells were identified. Additionally, an interferon stimulated gene signature was detected in the liver during EqHV infection, similar to acute HCV in humans. EqHV, as HCV, is stimulated by direct binding of the liver-specific microRNA, miR-122. Interestingly, we found that EqHV infection sequesters enough miR-122 to functionally affect gene regulation in the liver. This RNA-based mechanism thus could have consequences for pathology. Conclusions: EqHV infection in horses typically has an acute resolving course, and the protective immune response lasts for at least a year and broadly attenuates subsequent infections. This could have important implications to achieve the primary goal of an HCV vaccine; to prevent chronicity while accepting acute resolving infection after virus exposure.
Project description:Equine hepacivirus (EqHV) is the closest genetic relative of hepatitis C virus (HCV) and shares features of genome organization, hepatotropism, persistent infection, and the ability to cause liver disease. As such, EqHV studies are important both in order to understand equine liver disease, and as an outbred animal model for HCV pathogenesis and immune responses. Here, we characterize the natural history and immune response to EqHV infection. Seven horses were experimentally inoculated with EqHV, monitored for 6 months, and challenge inoculated with the same, and subsequently a divergent EqHV inoculum. Clearance was the primary outcome (6 of 7) and was associated with subclinical hepatitis characterized by lymphocytic infiltrate and individual hepatocyte necrosis. Seroconversion was delayed and antibody titers waned slowly. Resolving horses developed non-sterilizing immunity resulting in short duration of infection upon challenge. Unlike those observed in acutely HCV-infected patients, peripheral blood mononuclear cell responses in horses were minimal, although EqHV specific T-cells were identified. In contrast, an interferon stimulated gene signature was detected in the liver during EqHV infection, which is similar to acute HCV in humans. EqHV, similarly to HCV, is stimulated by direct binding of the liver-specific microRNA, miR-122. Surprisingly, we found that EqHV infection sequesters enough miR-122 to functionally affect gene regulation in the liver. This RNA-based mechanism thus could have consequences for pathology. Conclusion: EqHV infection in horses typically has an acute resolving course, and the immune response attenuates subsequent infections lasting for at least a year. This could have important implications to achieve the first goal of an HCV vaccine; to prevent chronicity while accepting acute resolving infection after challenge.
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 C virus uniquely requires the liver specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (Ago) during HCV infection showed robust Ago binding on the HCV 5’UTR, at known and predicted miR-122 sites. On the human transcriptome, we observed reduced Ago binding and functional mRNA de-repression of miR-122 targets during virus infection. This miR-122 “sponge” effect could be relieved and redirected to miR-15 targets by swapping the miRNA tropism of the virus. Single-cell expression data from reporters containing miR-122 sites showed significant de-repression during HCV infection depending on expression level and number of sites. We describe a quantitative mathematical model of HCV induced miR-122 sequestration and propose that such miR-122 inhibition by HCV RNA may result in global de-repression of host miR-122 targets, providing an environment fertile for the long-term oncogenic potential of HCV.
Project description:Hepatitis C virus uniquely requires the liver specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (Ago) during HCV infection showed robust Ago binding on the HCV 5’UTR, at known and predicted miR-122 sites. On the human transcriptome, we observed reduced Ago binding and functional mRNA de-repression of miR-122 targets during virus infection. This miR-122 “sponge” effect could be relieved and redirected to miR-15 targets by swapping the miRNA tropism of the virus. Single-cell expression data from reporters containing miR-122 sites showed significant de-repression during HCV infection depending on expression level and number of sites. We describe a quantitative mathematical model of HCV induced miR-122 sequestration and propose that such miR-122 inhibition by HCV RNA may result in global de-repression of host miR-122 targets, providing an environment fertile for the long-term oncogenic potential of HCV.
Project description:Hepatitis C virus uniquely requires the liver specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (Ago) during HCV infection showed robust Ago binding on the HCV 5’UTR, at known and predicted miR-122 sites. On the human transcriptome, we observed reduced Ago binding and functional mRNA de-repression of miR-122 targets during virus infection. This miR-122 “sponge” effect could be relieved and redirected to miR-15 targets by swapping the miRNA tropism of the virus. Single-cell expression data from reporters containing miR-122 sites showed significant de-repression during HCV infection depending on expression level and number of sites. We describe a quantitative mathematical model of HCV induced miR-122 sequestration and propose that such miR-122 inhibition by HCV RNA may result in global de-repression of host miR-122 targets, providing an environment fertile for the long-term oncogenic potential of HCV.
Project description:Hepatitis C virus uniquely requires the liver specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (Ago) during HCV infection showed robust Ago binding on the HCV 5’UTR, at known and predicted miR-122 sites. On the human transcriptome, we observed reduced Ago binding and functional mRNA de-repression of miR-122 targets during virus infection. This miR-122 “sponge” effect could be relieved and redirected to miR-15 targets by swapping the miRNA tropism of the virus. Single-cell expression data from reporters containing miR-122 sites showed significant de-repression during HCV infection depending on expression level and number of sites. We describe a quantitative mathematical model of HCV induced miR-122 sequestration and propose that such miR-122 inhibition by HCV RNA may result in global de-repression of host miR-122 targets, providing an environment fertile for the long-term oncogenic potential of HCV.
Project description:Hepatitis C virus uniquely requires the liver specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (Ago) during HCV infection showed robust Ago binding on the HCV 5’UTR, at known and predicted miR-122 sites. On the human transcriptome, we observed reduced Ago binding and functional mRNA de-repression of miR-122 targets during virus infection. This miR-122 “sponge” effect could be relieved and redirected to miR-15 targets by swapping the miRNA tropism of the virus. Single-cell expression data from reporters containing miR-122 sites showed significant de-repression during HCV infection depending on expression level and number of sites. We describe a quantitative mathematical model of HCV induced miR-122 sequestration and propose that such miR-122 inhibition by HCV RNA may result in global de-repression of host miR-122 targets, providing an environment fertile for the long-term oncogenic potential of HCV.
Project description:Hepatitis C virus uniquely requires the liver specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (Ago) during HCV infection showed robust Ago binding on the HCV 5’UTR, at known and predicted miR-122 sites. On the human transcriptome, we observed reduced Ago binding and functional mRNA de-repression of miR-122 targets during virus infection. This miR-122 “sponge” effect could be relieved and redirected to miR-15 targets by swapping the miRNA tropism of the virus. Single-cell expression data from reporters containing miR-122 sites showed significant de-repression during HCV infection depending on expression level and number of sites. We describe a quantitative mathematical model of HCV induced miR-122 sequestration and propose that such miR-122 inhibition by HCV RNA may result in global de-repression of host miR-122 targets, providing an environment fertile for the long-term oncogenic potential of HCV. mRNA-seq libraries were generated from mock or J6/JFH1 Clone2 infected Huh7.5 cells. Cells were infected at an MOI of 1-2 and harvested at 72 hours and 96 hours post-infection for CLIP. Libraries were generated using Illumina Truseq technology.