Division of experimental Virology ([TC]EVIR)
http://hdl.handle.net/10033/620589
2024-03-28T10:56:28Z
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Absence of cGAS-mediated type I IFN responses in HIV-1-infected T cells.
http://hdl.handle.net/10033/623245
Absence of cGAS-mediated type I IFN responses in HIV-1-infected T cells.
Elsner, Carina; Ponnurangam, Aparna; Kazmierski, Julia; Zillinger, Thomas; Jansen, Jenny; Todt, Daniel; Döhner, Katinka; Xu, Shuting; Ducroux, Aurélie; Kriedemann, Nils; Malassa, Angelina; Larsen, Pia-Katharina; Hartmann, Gunther; Barchet, Winfried; Steinmann, Eike; Kalinke, Ulrich; Sodeik, Beate; Goffinet, Christine
The DNA sensor cGAS catalyzes the production of the cyclic dinucleotide cGAMP, resulting in type I interferon responses. We addressed the functionality of cGAS-mediated DNA sensing in human and murine T cells. Activated primary CD4+ T cells expressed cGAS and responded to plasmid DNA by upregulation of ISGs and release of bioactive interferon. In mouse T cells, cGAS KO ablated sensing of plasmid DNA, and TREX1 KO enabled cells to sense short immunostimulatory DNA. Expression of IFIT1 and MX2 was downregulated and upregulated in cGAS KO and TREX1 KO T cell lines, respectively, compared to parental cells. Despite their intact cGAS sensing pathway, human CD4+ T cells failed to mount a reverse transcriptase (RT) inhibitor-sensitive immune response following HIV-1 infection. In contrast, infection of human T cells with HSV-1 that is functionally deficient for the cGAS antagonist pUL41 (HSV-1ΔUL41N) resulted in a cGAS-dependent type I interferon response. In accordance with our results in primary CD4+ T cells, plasmid challenge or HSV-1ΔUL41N inoculation of T cell lines provoked an entirely cGAS-dependent type I interferon response, including IRF3 phosphorylation and expression of ISGs. In contrast, no RT-dependent interferon response was detected following transduction of T cell lines with VSV-G-pseudotyped lentiviral or gammaretroviral particles. Together, T cells are capable to raise a cGAS-dependent cell-intrinsic response to both plasmid DNA challenge or inoculation with HSV-1ΔUL41N. However, HIV-1 infection does not appear to trigger cGAS-mediated sensing of viral DNA in T cells, possibly by revealing viral DNA of insufficient quantity, length, and/or accessibility to cGAS.
2020-07-24T00:00:00Z
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C19orf66 is an interferon-induced inhibitor of HCV replication that restricts formation of the viral replication organelle
http://hdl.handle.net/10033/623237
C19orf66 is an interferon-induced inhibitor of HCV replication that restricts formation of the viral replication organelle
Kinast, Volker; Plociennikowska, Agnieszka; Anggakusuma; Bracht, Thilo; Todt, Daniel; Brown, Richard J.P.; Boldanova, Tujana; Zhang, Yudi; Brüggemann, Yannick; Friesland, Martina; Engelmann, Michael; Vieyres, Gabrielle; Broering, Ruth; Vondran, Florian W.R.; Heim, Markus H.; Sitek, Barbara; Bartenschlager, Ralf; Pietschmann, Thomas; Steinmann, Eike
Background & Aims
HCV is a positive-strand RNA virus that primarily infects human hepatocytes. Recent studies have reported that C19orf66 is expressed as an interferon (IFN)-stimulated gene; however, the intrinsic regulation of this gene within the liver as well as its antiviral effects against HCV remain elusive.
Methods
Expression of C19orf66 was quantified in both liver biopsies and primary human hepatocytes, with or without HCV infection. Mechanistic studies of the potent anti-HCV phenotype mediated by C19orf66 were conducted using state-of-the-art virological, biochemical and genetic approaches, as well as correlative light and electron microscopy and transcriptome and proteome analysis.
Results
Upregulation of C19orf66 mRNA was observed in both primary human hepatocytes upon HCV infection and in the livers of patients with chronic hepatitis C (CHC). In addition, pegIFNα/ribavirin therapy induced C19orf66 expression in patients with CHC. Transcriptomic profiling and whole cell proteomics of hepatoma cells ectopically expressing C19orf66 revealed no induction of other antiviral genes. Expression of C19orf66 restricted HCV infection, whereas CRIPSPR/Cas9 mediated knockout of C19orf66 attenuated IFN-mediated suppression of HCV replication. Co-immunoprecipitation followed by mass spectrometry identified a stress granule protein-dominated interactome of C19orf66. Studies with subgenomic HCV replicons and an expression system revealed that C19orf66 expression impairs HCV-induced elevation of phosphatidylinositol-4-phosphate, alters the morphology of the viral replication organelle (termed the membranous web) and thereby targets viral RNA replication.
Conclusion
C19orf66 is an IFN-stimulated gene, which is upregulated in hepatocytes within the first hours post IFN treatment or HCV infection in vivo. The encoded protein possesses specific antiviral activity against HCV and targets the formation of the membranous web. Our study identifies C19orf66 as an IFN-inducible restriction factor with a novel antiviral mechanism that specifically targets HCV replication.
ackground & Aims: HCV is a positive-strand RNA virus that primarily infects human hepatocytes. Recent studies have reported that C19orf66 is expressed as an interferon (IFN)-stimulated gene; however, the intrinsic regulation of this gene within the liver as well as its antiviral effects against HCV remain elusive. Methods: Expression of C19orf66 was quantified in both liver biopsies and primary human hepatocytes, with or without HCV infection. Mechanistic studies of the potent anti-HCV phenotype mediated by C19orf66 were conducted using state-of-the-art virological, biochemical and genetic approaches, as well as correlative light and electron microscopy and transcriptome and proteome analysis. Results: Upregulation of C19orf66 mRNA was observed in both primary human hepatocytes upon HCV infection and in the livers of patients with chronic hepatitis C (CHC). In addition, pegIFNα/ribavirin therapy induced C19orf66 expression in patients with CHC. Transcriptomic profiling and whole cell proteomics of hepatoma cells ectopically expressing C19orf66 revealed no induction of other antiviral genes. Expression of C19orf66 restricted HCV infection, whereas CRIPSPR/Cas9 mediated knockout of C19orf66 attenuated IFN-mediated suppression of HCV replication. Co-immunoprecipitation followed by mass spectrometry identified a stress granule protein-dominated interactome of C19orf66. Studies with subgenomic HCV replicons and an expression system revealed that C19orf66 expression impairs HCV-induced elevation of phosphatidylinositol-4-phosphate, alters the morphology of the viral replication organelle (termed the membranous web) and thereby targets viral RNA replication. Conclusion: C19orf66 is an IFN-stimulated gene, which is upregulated in hepatocytes within the first hours post IFN treatment or HCV infection in vivo. The encoded protein possesses specific antiviral activity against HCV and targets the formation of the membranous web. Our study identifies C19orf66 as an IFN-inducible restriction factor with a novel antiviral mechanism that specifically targets HCV replication. Lay summary: Interferon-stimulated genes are thought to be important to for antiviral immune responses to HCV. Herein, we analysed C19orf66, an interferon-stimulated gene, which appears to inhibit HCV replication. It prevents the HCV-induced elevation of phosphatidylinositol-4-phosphate and alters the morphology of HCV's replication organelle. © 2020 European Association for the Study of the Liver
2020-04-12T00:00:00Z
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C19orf66 is an interferon-induced inhibitor of HCV replication that restricts formation of the viral replication organelle.
http://hdl.handle.net/10033/623222
C19orf66 is an interferon-induced inhibitor of HCV replication that restricts formation of the viral replication organelle.
Kinast, Volker; Plociennikowska, Agnieszka; Anggakusuma; Bracht, Thilo; Todt, Daniel; Brown, Richard J P; Boldanova, Tujana; Zhang, Yudi; Brüggemann, Yannick; Friesland, Martina; Engelmann, Michael; Vieyres, Gabrielle; Broering, Ruth; Vondran, Florian W R; Heim, Markus H; Sitek, Barbara; Bartenschlager, Ralf; Pietschmann, Thomas; Steinmann, Eike
2020-04-12T00:00:00Z
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Microbiota-Induced Type I Interferons Instruct a Poised Basal State of Dendritic Cells.
http://hdl.handle.net/10033/623220
Microbiota-Induced Type I Interferons Instruct a Poised Basal State of Dendritic Cells.
Schaupp, Laura; Muth, Sabine; Rogell, Leif; Kofoed-Branzk, Michael; Melchior, Felix; Lienenklaus, Stefan; Ganal-Vonarburg, Stephanie C; Klein, Matthias; Guendel, Fabian; Hain, Tobias; Schütze, Kristian; Grundmann, Ulrike; Schmitt, Vanessa; Dorsch, Martina; Spanier, Julia; Larsen, Pia-Katharina; Schwanz, Thomas; Jäckel, Sven; Reinhardt, Christoph; Bopp, Tobias; Danckwardt, Sven; Mahnke, Karsten; Heinz, Gitta Anne; Mashreghi, Mir-Farzin; Durek, Pawel; Kalinke, Ulrich; Kretz, Oliver; Huber, Tobias B; Weiss, Siegfried; Wilhelm, Christoph; Macpherson, Andrew J; Schild, Hansjörg; Diefenbach, Andreas; Probst, Hans Christian
Environmental signals shape host physiology and fitness. Microbiota-derived cues are required to program
conventional dendritic cells (cDCs) during the steady state so that they can promptly respond and initiate
adaptive immune responses when encountering pathogens. However, the molecular underpinnings of microbiota-
guided instructive programs are not well understood. Here, we report that the indigenous microbiota
controls constitutive production of type I interferons (IFN-I) by plasmacytoid DCs. Using genome-wide analysis
of transcriptional and epigenetic regulomes of cDCs from germ-free and IFN-I receptor (IFNAR)-deficient
mice, we found that tonic IFNAR signaling instructs a specific epigenomic and metabolic basal state that
poises cDCs for future pathogen combat. However, such beneficial biological function comes with a
trade-off. Instructed cDCs can prime T cell responses against harmless peripheral antigens when removing
roadblocks of peripheral tolerance. Our data provide fresh insights into the evolutionary trade-offs that come
with successful adaptation of vertebrates to their microbial environment.
2020-05-06T00:00:00Z