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Sharon AJ, Filyk HA, Fonseca NM, Simister RL, Filler RB, Yuen W, Hardman BK, Robinson HG, Seo JH, Rocha-Pereira J, Welch I, Neyts J, Wilen CB, Crowe SA, Osborne LC. Restriction of viral replication, rather than T cell immunopathology, drives lethality in MNV CR6-infected STAT1-deficient mice. The Journal of Immunology 2022. [DOI: 10.4049/jimmunol.208.supp.182.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abstract
Recent evidence indicates that viral components of the microbiota can contribute to intestinal homeostasis and protection from local inflammatory or infectious insults. However, host-derived mechanisms that regulate the virome remain largely unknown. Here, we used colonization of C57BL6/J mice with the model commensal murine norovirus (MNV CR6) to interrogate host-directed mechanisms of viral regulation, and show that STAT1 is a central coordinator of both viral replication and antiviral T cell responses. In STAT1-sufficient mice MNV CR6 is asymptomatic and restricted to the colon, despite the persistence of high viral loads. However, in the absence of STAT1 viral replication is disseminated and observed in key innate and adaptive immune populations.
STAT1-deficient mice develop dysregulated inflammatory CD8+ and CD4+ T cell responses, which coincide with weight loss and severe necrosis of the spleen and liver. Despite these altered T cell responses which resemble those that mediate lethal immunopathology following other model viral infections of STAT1-deficient mice, depletion of adaptive immune cells and their associated effector functions had no effect on CR6-induced disease. In contrast, therapeutic administration of an antiviral compound limited viral replication, preventing viral-induced tissue damage and death despite ongoing inflammatory antiviral T cell responses. Collectively, our data show that STAT1 restricts MNV CR6 replication within the intestinal mucosa. Unlike other model viral infections, CR6 induces disease in STAT1-deficient mice via uncontrolled viral replication rather than the concomitant development of dysregulated antiviral T cell responses.
Research in the Osborne lab is supported by the Natural Sciences and Engineering Research Council of Canada, the Canadian Institutes of Health Research, the Canada Research Chair program and scholarships from the University of British Columbia.
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Affiliation(s)
- Andrew J Sharon
- 1Microbiology and Immunology, Univ. of British Columbia, Canada
| | - Heather A Filyk
- 1Microbiology and Immunology, Univ. of British Columbia, Canada
| | | | | | | | - Wallace Yuen
- 1Microbiology and Immunology, Univ. of British Columbia, Canada
| | - Blair K Hardman
- 1Microbiology and Immunology, Univ. of British Columbia, Canada
| | | | - Jung Hee Seo
- 1Microbiology and Immunology, Univ. of British Columbia, Canada
| | | | - Ian Welch
- 4Pathology, Univ. of British Columbia, Canada
| | - Johan Neyts
- 3Microbiology and Immunology, Univ. of Leuven, Belgium
| | | | - Sean A Crowe
- 1Microbiology and Immunology, Univ. of British Columbia, Canada
| | - Lisa C Osborne
- 1Microbiology and Immunology, Univ. of British Columbia, Canada
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Sharon AJ, Filyk HA, Fonseca NM, Simister RL, Yuen W, Hardman BK, Robinson HG, Seo JH, Rocha-Pereira J, Welch I, Neyts J, Crowe SA, Osborne LC. STAT1-dependent tolerance of intestinal viral infection. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.249.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
The diverse commensal ecosystem present in the mammalian intestine requires the host immune system to maintain a tolerogenic environment. The virome is an understudied component of the microbiota which promotes intestinal homeostasis and protection from injury, but the host mechanisms that regulate tolerance to viral commensals are poorly described. The antiviral signal transducer STAT1 has previously been shown to mediate tolerance to systemic viral pathogens by suppressing adaptive immune responses and protecting the host from immunopathology, but we sought to characterize its role in the context of a commensal intestinal viral infection.
We used a persistent strain of murine norovirus (MNV CR6) to interrogate host mechanisms of viral tolerance and commensalism, as CR6 has previously been shown to promote intestinal homeostasis. While CR6 infections of wildtype mice were asymptomatic and limited to the colon, STAT1-deficient mice exhibited virus-induced weight loss and mortality accompanied by systemic viral spread, colonic bacterial dysbiosis, CD4+ T cell dysfunction and hyperaccumulation of CD8+ T cells. However, clinical manifestation of virus-induced disease in STAT1-deficient mice was independent of T cells and the bacterial microbiota. Instead, therapeutic control of viral replication was sufficient to prevent virus-induced disease despite ongoing T cell dysregulation. Collectively, our data indicate that STAT1 maintains tolerance to a viral component of the intestinal microbiota by control of viral replication rather than immunopathology, suggesting that STAT1 uses distinct strategies to tolerate pathogenic and commensal viruses.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Joana Rocha-Pereira
- 2Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium, Belgium
| | - Ian Welch
- 1University of British Columbia, Canada
| | - Johan Neyts
- 2Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium, Belgium
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Filyk HA, Osborne LC. The Multibiome: The Intestinal Ecosystem's Influence on Immune Homeostasis, Health, and Disease. EBioMedicine 2016; 13:46-54. [PMID: 27863931 PMCID: PMC5264270 DOI: 10.1016/j.ebiom.2016.10.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/05/2016] [Accepted: 10/05/2016] [Indexed: 12/13/2022] Open
Abstract
Mammalian evolution has occurred in the presence of mutualistic, commensal, and pathogenic micro- and macro-organisms for millennia. The presence of these organisms during mammalian evolution has allowed for intimate crosstalk between these colonizing species and the host immune system. In this review, we introduce the concept of the ‘multibiome’ to holistically refer to the biodiverse collection of bacteria, viruses, fungi and multicellular helminthic worms colonizing the mammalian intestine. Furthermore, we discuss new insights into multibiome-host interactions in the context of host-protective immunity and immune-mediated diseases, including inflammatory bowel disease and multiple sclerosis. Finally, we provide reasons to account for the multibiome in experimental design, analysis and in therapeutic applications. The intestinal multibiome is composed of bacteria, viruses, fungi, and eukaryotes. Mammals evolved alongside a complex and biodiverse multibiome. Cross-talk between the multibiome and the host regulates immunity and inflammation.
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Affiliation(s)
- Heather A Filyk
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Lisa C Osborne
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.
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