The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Terence S. Dermody - One of the best experts on this subject based on the ideXlab platform.
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murine norovirus Infection induces th1 inflammatory responses to dietary antigens
Cell Host & Microbe, 2018Co-Authors: Romain Bouziat, Scott B Biering, Elaine Kouame, Kishan Sangani, Soowon Kang, Jordan D Ernest, Mukund Varma, Judy J Brown, Kelly Urbanek, Terence S. DermodyAbstract:Summary Intestinal Reovirus Infection can trigger T helper 1 (TH1) immunity to dietary antigen, raising the question of whether other viruses can have a similar impact. Here we show that the acute CW3 strain of murine norovirus, but not the persistent CR6 strain, induces TH1 immunity to dietary antigen. This property of CW3 is dependent on its major capsid protein, a virulence determinant. Transcriptional profiling of mesenteric lymph nodes following Infection reveals an immunopathological signature that does not segregate with protective immunity but with loss of oral tolerance, in which interferon regulatory factor 1 is critical. These data show that viral capacity to trigger specific inflammatory pathways at sites where T cell responses to dietary antigens take place interferes with the development of tolerance to an oral antigen. Collectively, these data provide a foundation for the development of therapeutic strategies to prevent TH1-mediated complex immune disorders triggered by viral Infections.
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Antagonism of the Sodium-Potassium ATPase Impairs Chikungunya Virus Infection
American Society for Microbiology, 2016Co-Authors: Alison W. Ashbrook, Anthony J. Lentscher, Paula F. Zamora, Laurie A. Silva, Nicholas A. May, Joshua A. Bauer, Thomas E. Morrison, Terence S. DermodyAbstract:Chikungunya virus (CHIKV) is a reemerging alphavirus that has caused epidemics of fever, arthralgia, and rash worldwide. There are currently no licensed vaccines or antiviral therapies available for the prevention or treatment of CHIKV disease. We conducted a high-throughput, chemical compound screen that identified digoxin, a cardiac glycoside that blocks the sodium-potassium ATPase, as a potent inhibitor of CHIKV Infection. Treatment of human cells with digoxin or a related cardiac glycoside, ouabain, resulted in a dose-dependent decrease in Infection by CHIKV. Inhibition by digoxin was cell type-specific, as digoxin treatment of either murine or mosquito cells did not diminish CHIKV Infection. Digoxin displayed antiviral activity against other alphaviruses, including Ross River virus and Sindbis virus, as well as mammalian Reovirus and vesicular stomatitis virus. The digoxin-mediated block to CHIKV and Reovirus Infection occurred at one or more postentry steps, as digoxin inhibition was not bypassed by fusion of CHIKV at the plasma membrane or Infection with cell surface-penetrating Reovirus entry intermediates. Selection of digoxin-resistant CHIKV variants identified multiple mutations in the nonstructural proteins required for replication complex formation and synthesis of viral RNA. These data suggest a role for the sodium-potassium ATPase in promoting postentry steps of CHIKV replication and provide rationale for modulation of this pathway as a broad-spectrum antiviral strategy
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Serotonin Receptor Agonist 5-Nonyloxytryptamine Alters the Kinetics of Reovirus Cell Entry
Journal of Virology, 2015Co-Authors: Bernardo A. Mainou, Alison W. Ashbrook, Everett Clinton Smith, Daniel C. Dorset, Mark R. Denison, Terence S. DermodyAbstract:ABSTRACT Mammalian orthoReoviruses (Reoviruses) are nonenveloped double-stranded RNA viruses that infect most mammalian species, including humans. Reovirus binds to cell surface glycans, junctional adhesion molecule A (JAM-A), and the Nogo-1 receptor (depending on the cell type) and enters cells by receptor-mediated endocytosis. Within the endocytic compartment, Reovirus undergoes stepwise disassembly, which is followed by release of the transcriptionally active viral core into the cytoplasm. In a small-molecule screen to identify host mediators of Reovirus Infection, we found that treatment of cells with 5-nonyloxytryptamine (5-NT), a prototype serotonin receptor agonist, diminished Reovirus cytotoxicity. 5-NT also blocked Reovirus Infection. In contrast, treatment of cells with methiothepin mesylate, a serotonin antagonist, enhanced Infection by Reovirus. 5-NT did not alter cell surface expression of JAM-A or attachment of Reovirus to cells. However, 5-NT altered the distribution of early endosomes with a concomitant impairment of Reovirus transit to late endosomes and a delay in Reovirus disassembly. Consistent with an inhibition of viral disassembly, 5-NT treatment did not alter Infection by in vitro -generated infectious subvirion particles, which bind to JAM-A but bypass a requirement for proteolytic uncoating in endosomes to infect cells. We also found that treatment of cells with 5-NT decreased the infectivity of alphavirus chikungunya virus and coronavirus mouse hepatitis virus. These data suggest that serotonin receptor signaling influences cellular activities that regulate entry of diverse virus families and provides a new, potentially broad-spectrum target for antiviral drug development. IMPORTANCE Identification of well-characterized small molecules that modulate viral Infection can accelerate development of antiviral therapeutics while also providing new tools to increase our understanding of the cellular processes that underlie virus-mediated cell injury. We conducted a small-molecule screen to identify compounds capable of inhibiting cytotoxicity caused by Reovirus, a prototype double-stranded RNA virus. We found that 5-nonyloxytryptamine (5-NT) impairs Reovirus Infection by altering viral transport during cell entry. Remarkably, 5-NT also inhibits Infection by an alphavirus and a coronavirus. The antiviral properties of 5-NT suggest that serotonin receptor signaling is an important regulator of Infection by diverse virus families and illuminate a potential new drug target.
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the nogo receptor ngr1 mediates Infection by mammalian Reovirus
Cell Host & Microbe, 2014Co-Authors: Jennifer L Konopkaanstadt, Bernardo A. Mainou, Danica M Sutherland, Yuichi Sekine, Stephen M Strittmatter, Terence S. DermodyAbstract:Neurotropic viruses, including mammalian Reovirus, must disseminate from an initial site of replication to the central nervous system (CNS), often binding multiple receptors to facilitate systemic spread. Reovirus engages junctional adhesion molecule A (JAM-A) to disseminate hematogenously. However, JAM-A is dispensable for Reovirus replication in the CNS. We demonstrate that Reovirus binds Nogo receptor NgR1, a leucine-rich repeat protein expressed in the CNS, to infect neurons. Expression of NgR1 confers Reovirus binding and Infection of nonsusceptible cells. Incubating Reovirus virions with soluble NgR1 neutralizes infectivity. Blocking NgR1 on transfected cells or primary cortical neurons abrogates Reovirus Infection. Concordantly, Reovirus Infection is ablated in primary cortical neurons derived from NgR1 null mice. Reovirus virions bind to soluble JAM-A and NgR1, while infectious disassembly intermediates (ISVPs) bind only to JAM-A. These results suggest that Reovirus uses different capsid components to bind distinct cell-surface molecules, engaging independent receptors to facilitate spread and tropism.
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optimum length and flexibility of Reovirus attachment protein σ1 are required for efficient viral Infection
Journal of Virology, 2012Co-Authors: Magdalena Bokiej, Kristen M Ogden, Mine R Ikizler, Dirk M Reiter, Thilo Stehle, Terence S. DermodyAbstract:Reovirus attachment protein σ1 is an elongated trimer with head-and-tail morphology that engages cell-surface carbohydrate and junctional adhesion molecule A (JAM-A). The σ1 protein is comprised of three domains partitioned by two flexible linkers termed interdomain regions (IDRs). To determine the importance of σ1 length and flexibility at different stages of Reovirus Infection, we generated viruses with mutant σ1 molecules of altered length and flexibility and tested these viruses for the capacity to bind the cell surface, internalize, uncoat, induce protein synthesis, assemble, and replicate. We reduced the length of the α-helical σ1 tail to engineer mutants L1 and L2 and deleted midpoint and head-proximal σ1 IDRs to generate ΔIDR1 and ΔIDR2 mutant viruses, respectively. Decreasing length or flexibility of σ1 resulted in delayed Reovirus Infection and reduced viral titers. L1, L2, and ΔIDR1 viruses but not ΔIDR2 virus displayed reduced cell attachment, but altering σ1 length or flexibility did not diminish the efficiency of virion internalization. Replication of ΔIDR2 virus was hindered at a postdisassembly step. Differences between wild-type and σ1 mutant viruses were not attributable to alterations in σ1 folding, as determined by experiments assessing engagement of cell-surface carbohydrate and JAM-A by the length and IDR mutant viruses. However, ΔIDR1 virus harbored substantially less σ1 on the outer capsid. Taken together, these data suggest that σ1 length is required for Reovirus binding to cells. In contrast, IDR1 is required for stable σ1 encapsidation, and IDR2 is required for a postuncoating replication step. Thus, the structural architecture of σ1 is required for efficient Reovirus Infection of host cells.
Kenneth L Tyler - One of the best experts on this subject based on the ideXlab platform.
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interferon beta contributes to astrocyte activation in the brain following Reovirus Infection
Journal of Virology, 2019Co-Authors: Penny Clarke, Smith J Leser, Yonghua Zhuang, Heather M Berens, Kenneth L TylerAbstract:Reovirus encephalitis in mice was used as a model system to investigate astrocyte activation (astrogliosis) following viral Infection of the brain. Reovirus Infection resulted in astrogliosis, as evidenced by increased expression of glial fibrillary acidic protein (GFAP), and the upregulation of genes that have been previously associated with astrocyte activation. Astrocyte activation occurred in regions of the brain that are targeted by Reovirus but extended beyond areas of active Infection. Astrogliosis also occurred following Reovirus Infection of ex vivo brain slice cultures (BSCs), demonstrating that factors intrinsic to the brain are sufficient to activate astrocytes and that this process can occur in the absence of any contribution from the peripheral immune response. In agreement with previous reports, Reovirus antigen did not colocalize with GFAP in infected brains, suggesting that Reovirus does not infect astrocytes. Reovirus-infected neurons produce interferon beta (IFN-β). IFN-β treatment of primary astrocytes resulted in both the upregulation of GFAP and cytokines that are associated with astrocyte activation. In addition, the ability of media from Reovirus-infected BSCs to activate primary astrocytes was blocked by anti-IFN-β antibodies. These results suggest that IFN-β, likely released from Reovirus-infected neurons, results in the activation of astrocytes during Reovirus encephalitis. In areas where Infection and injury were pronounced, an absence of GFAP staining was consistent with activation-induced cell death as a mechanism of inflammation control. In support of this, activated Bak and cleaved caspase 3 were detected in astrocytes within Reovirus-infected brains, indicating that activated astrocytes undergo apoptosis.IMPORTANCE Viral encephalitis is a significant cause of worldwide morbidity and mortality, and specific treatments are extremely limited. Virus Infection of the brain triggers neuroinflammation; however, the role of neuroinflammation in the pathogenesis of viral encephalitis is unclear. Initial neuroinflammatory responses likely contribute to viral clearance, but prolonged exposure to proinflammatory cytokines released during neuroinflammation may be deleterious and contribute to neuronal death and tissue injury. Activation of astrocytes is a hallmark of neuroinflammation. Here, we show that Reovirus Infection of the brain results in the activation of astrocytes via an IFN-β-mediated process and that these astrocytes later die by Bak-mediated apoptosis. A better understanding of neuroinflammatory responses during viral encephalitis may facilitate the development of new treatment strategies for these diseases.
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a brain slice culture model of viral encephalitis reveals an innate cns cytokine response profile and the therapeutic potential of caspase inhibition
Experimental Neurology, 2011Co-Authors: Kalen R Dionne, Smith J Leser, Kristi A Lorenzen, David J Beckham, Kenneth L TylerAbstract:Viral encephalitis is a significant cause of human morbidity and mortality in large part due to suboptimal diagnosis and treatment. Murine Reovirus Infection serves as a classic experimental model of viral encephalitis. Infection of neonatal mice with T3 Reoviruses results in lethal encephalitis associated with neuronal Infection, apoptosis, and CNS tissue injury. We have developed an ex vivo brain slice culture (BSC) system that recapitulates the basic pathological features and kinetics of viral replication seen in vivo. We utilize the BSC model to identify an innate, brain-tissue specific inflammatory cytokine response to reoviral Infection, which is characterized by the release of IL6, CXCL10, RANTES, and murine IL8 analog (KC). Additionally, we demonstrate the potential utility of this system as a pharmaceutical screening platform by inhibiting Reovirus-induced apoptosis and CNS tissue injury with the pan-caspase inhibitor, Q-VD-OPh. Cultured brain slices not only serve to model events occurring during viral encephalitis, but can also be utilized to investigate aspects of pathogenesis and therapy that are not experimentally accessible in vivo.
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cardiac cell specific apoptotic and cytokine responses to Reovirus Infection determinants of myocarditic phenotype
Journal of Cardiac Failure, 2009Co-Authors: Shelley D Miyamoto, Kenneth L Tyler, Roberta L Debiasi, R D Brown, Bridget A Robinson, Carlin S LongAbstract:Background The pathophysiologic mechanisms underlying viral myocarditis are not well defined. As a result, effective treatments do not exist and viral myocarditis remains a potentially lethal Infection of the heart.
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fas mediated apoptotic signaling in the mouse brain following Reovirus Infection
Journal of Virology, 2009Co-Authors: Penny Clarke, David J Beckham, Smith J Leser, Cristen C Hoyt, Kenneth L TylerAbstract:Type 3 (T3) Reovirus strains induce apoptotic neuronal cell death and lethal encephalitis in infected mice. T3 strain Dearing (T3D)-induced apoptosis in primary neuronal cultures occurs by a Fas-mediated mechanism and requires the activation of caspase 8. We now show that Fas mRNA is upregulated in the brains of mice infected with encephalitic Reovirus T3D and T3 strain Abney (T3A) but not following Infection with nonencephalitic Reovirus type 1 strain Lang. Fas is upregulated in regions of the brain that are injured during Infection with T3 Reovirus strains and colocalizes with virus antigen in individual neurons. In contrast, levels of FasL mRNA induced by encephalitic and nonencephalitic Reovirus strains do not differ significantly. Caspase 8, the initiator caspase associated with Fas-mediated apoptosis, is activated in the cortex and hippocampal regions of both T3D- and T3A-infected mice. Furthermore, Bid cleavage and the activation of caspase 9 in the brains of T3D-infected mice suggest that the caspase 8-dependent activation of mitochondrial apoptotic signaling contributes to virus-induced apoptosis. We have previously shown that the inhibition of c-Jun N-terminal kinase (JNK) signaling blocks T3D-induced apoptosis and improves the outcome of virus-induced encephalitis. We now show that the Reovirus-induced upregulation of Fas requires JNK signaling, thereby providing a link between Reovirus-induced death receptor signaling and mitogen-activated protein kinase pathways and a potential mechanism for the therapeutic action of JNK inhibition.
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Reovirus activates transforming growth factor β and bone morphogenetic protein signaling pathways in the central nervous system that contribute to neuronal survival following Infection
Journal of Virology, 2009Co-Authors: David J Beckham, Kenneth L Tyler, Kathryn D TuttleAbstract:Viral Infections of the central nervous system (CNS) are important causes of worldwide morbidity and mortality, and understanding how viruses perturb host cell signaling pathways will facilitate identification of novel antiviral therapies. We now show that Reovirus Infection activates transforming growth factor beta (TGF-beta) and bone morphogenetic protein (BMP) signaling in a murine model of encephalitis in vivo. TGF-beta receptor I (TGF-beta RI) expression is increased and its downstream signaling factor, SMAD3, is activated in the brains of Reovirus-infected mice. TGF-beta signaling is neuroprotective, as inhibition with a TGF-beta RI inhibitor increases death of infected neurons. Similarly, BMP receptor I expression is increased and its downstream signaling factor, SMAD1, is activated in Reovirus-infected neurons in the brains of infected mice in vivo. Activated SMAD1 and SMAD3 were both detected in regions of brain infected by Reovirus, but activated SMAD1 was found predominantly in uninfected neurons in close proximity to infected neurons. Treatment of Reovirus-infected primary mouse cortical neurons with a BMP agonist reduced apoptosis. These data provide the first evidence for the activation of TGF-beta and BMP signaling pathways following neurotropic viral Infection and suggest that these signaling pathways normally function as part of the host's protective innate immune response against CNS viral Infection.
Pavithra Aravamudhan - One of the best experts on this subject based on the ideXlab platform.
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cytidine monophosphate n acetylneuraminic acid synthetase and solute carrier family 35 member a1 are required for Reovirus binding and Infection
Journal of Virology, 2020Co-Authors: Kelly Urbanek, Danica M Sutherland, Robert C Orchard, Craig B Wilen, Jonathan J Knowlton, Pavithra AravamudhanAbstract:Engagement of cell-surface receptors by viruses is a critical determinant of viral tropism and disease. The Reovirus attachment protein, σ1, binds sialylated glycans and proteinaceous receptors to mediate Infection, but the specific requirements on different cell types are not entirely known. To identify host factors required for Reovirus-induced cell death, we conducted a CRISPR-knockout screen targeting over 20,000 genes in murine microglial BV2 cells. Candidate genes required for Reovirus to cause cell death were highly enriched for sialic acid synthesis and transport. Two of the top candidates identified, cytidine monophosphate N-acetylneuraminic acid synthetase (Cmas) and solute carrier family 35 member A1 (Slc35a1), promote sialic acid expression on the cell surface. Two Reovirus strains that differ in the capacity to bind sialic acid, T3SA+ and T3SA-, were used to evaluate Cmas and Slc35a1 as potential host genes required for Reovirus Infection. Following CRISPR-Cas9 disruption of either gene, cell-surface expression of sialic acid was diminished. These results correlated with decreased binding of strain T3SA+, which is capable of engaging sialic acid. Disruption of either gene did not alter the low-level binding of T3SA-, which does not engage sialic acid. Furthermore, infectivity of T3SA+ was diminished to levels of T3SA- in cells lacking Cmas and Slc35a1 by CRISPR ablation. However, exogenous expression of Cmas and Slc35a1 into the respective null cells restored sialic acid expression and T3SA+ binding and infectivity. These results demonstrate that Cmas and Slc35a1, which mediate cell-surface expression of sialic acid, are required in murine microglial cells for efficient Reovirus binding and Infection.IMPORTANCE Attachment factors and receptors are important determinants of dissemination and tropism during Reovirus-induced disease. In a CRISPR cell-survival screen, we discovered two genes, Cmas and Slc35a1, which encode proteins required for sialic acid expression on the cell surface, that mediate Reovirus Infection of microglial cells. This work elucidates host genes that render microglial cells susceptible to Reovirus Infection and expands current understanding of the receptors on microglial cells that are engaged by Reovirus. Such knowledge may lead to new strategies to selectively target microglial cells for oncolytic applications.
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cytidine monophosphate n acetylneuraminic acid synthetase and solute carrier family 35 member a1 are required for Reovirus binding and Infection
Journal of Virology, 2020Co-Authors: Kelly Urbanek, Danica M Sutherland, Robert C Orchard, Craig B Wilen, Jonathan J Knowlton, Pavithra AravamudhanAbstract:Engagement of cell surface receptors by viruses is a critical determinant of viral tropism and disease. The Reovirus attachment protein σ1 binds sialylated glycans and proteinaceous receptors to mediate Infection, but the specific requirements for different cell types are not entirely known. To identify host factors required for Reovirus-induced cell death, we conducted a CRISPR-knockout screen targeting over 20,000 genes in murine microglial BV2 cells. Candidate genes required for Reovirus to cause cell death were highly enriched for sialic acid synthesis and transport. Two of the top candidates identified, CMP N-acetylneuraminic acid synthetase (Cmas) and solute carrier family 35 member A1 (Slc35a1), promote sialic acid expression on the cell surface. Two Reovirus strains that differ in the capacity to bind sialic acid, T3SA+ and T3SA-, were used to evaluate Cmas and Slc35a1 as potential host genes required for Reovirus Infection. Following CRISPR-Cas9 disruption of either gene, cell surface expression of sialic acid was diminished. These results correlated with decreased binding of strain T3SA+, which is capable of engaging sialic acid. Disruption of either gene did not alter the low-level binding of T3SA-, which does not engage sialic acid. Furthermore, infectivity of T3SA+ was diminished to levels similar to those of T3SA- in cells lacking Cmas and Slc35a1 by CRISPR ablation. However, exogenous expression of Cmas and Slc35a1 into the respective null cells restored sialic acid expression and T3SA+ binding and infectivity. These results demonstrate that Cmas and Slc35a1, which mediate cell surface expression of sialic acid, are required in murine microglial cells for efficient Reovirus binding and Infection.IMPORTANCE Attachment factors and receptors are important determinants of dissemination and tropism during Reovirus-induced disease. In a CRISPR cell survival screen, we discovered two genes, Cmas and Slc35a1, which encode proteins required for sialic acid expression on the cell surface and mediate Reovirus Infection of microglial cells. This work elucidates host genes that render microglial cells susceptible to Reovirus Infection and expands current understanding of the receptors on microglial cells that are engaged by Reovirus. Such knowledge may lead to new strategies to selectively target microglial cells for oncolytic applications.
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cytidine monophosphate n acetylneuraminic acid synthetase and solute carrier family 35 member a1 are required for Reovirus binding and Infection
bioRxiv, 2020Co-Authors: Kelly Urbanek, Danica M Sutherland, Robert C Orchard, Craig B Wilen, Jonathan J Knowlton, Pavithra AravamudhanAbstract:ABSTRACT Engagement of cell-surface receptors by viruses is a critical determinant of viral tropism and disease. The Reovirus attachment protein, σ1, binds sialylated glycans and proteinaceous receptors to mediate Infection, but the specific requirements on different cell types are unknown. To identify host factors required for Reovirus-induced cell death, we conducted a CRISPR-knockout screen targeting over 20,000 genes in murine microglial BV2 cells. Candidate genes identified as required for Reovirus to cause cell death were highly enriched for sialic acid synthesis and transport. Two of the top candidates identified, cytidine monophosphate N-acetylneuraminic acid synthetase (Cmas) and solute carrier family 35 member A1 (Slc35a1), promote sialic acid expression on the cell surface. Two Reovirus strains differing in the capacity to bind sialic acid, T3SA+ and T3SA-, were used to evaluate Cmas and Slc35a1 as potential host genes required for Infection. Following CRISPR-Cas9 disruption of either gene, cell-surface expression of sialic acid was diminished. These results correlated with decreased binding of strain T3SA+, which is capable of engaging sialic acid. Disruption of either gene did not alter the low-level binding of T3SA-, which does not engage sialic acid. Infectivity of T3SA+ was diminished to levels of T3SA-in cells lacking Cmas and Slc35a1 by CRISPR ablation. However, exogenous expression of Cmas and Slc35a1 into the respective null cells restored sialic acid expression and T3SA+ binding and infectivity. These results demonstrate that Cmas and Slc35a1, which mediate cell-surface expression of sialic acid, are required in murine microglial cells for efficient Reovirus binding and Infection. IMPORTANCE Attachment factors and receptors are important determinants of dissemination and tropism during Reovirus-induced disease. In a CRISPR cell-survival screen, we discovered two genes, Cmas and Slc35a1, which encode proteins required for sialic acid expression on the cell surface, that mediate Reovirus Infection of microglial cells. This work elucidates host genes that render microglial cells susceptible to Reovirus Infection and expands current understanding of the receptors on microglial cells that are engaged by Reovirus. Such knowledge may lead to new strategies to selectively target microglial cells for oncolytic applications.
Geoffrey H Holm - One of the best experts on this subject based on the ideXlab platform.
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25 hydroxycholesterol production by the cholesterol 25 hydroxylase interferon stimulated gene restricts mammalian Reovirus Infection
Journal of Virology, 2018Co-Authors: Alexandra Doms, Tatiana Sanabria, Jeanne N Hansen, Nihal Altanbonnet, Geoffrey H HolmAbstract:Following the initial detection of viral Infection, innate immune responses trigger the induction of numerous interferon-stimulated genes (ISGs) to inhibit virus replication and dissemination. One such ISG encodes cholesterol-25-hydroxylase (CH25H), an enzyme that catalyzes the oxidation of cholesterol to form a soluble product, 25-hydroxycholesterol (25HC). Recent studies have found that CH25H is broadly antiviral; it inhibits Infection by several viruses. For enveloped viruses, 25HC inhibits membrane fusion, likely by altering membrane characteristics such as hydrophobicity or cholesterol aggregation. However, the mechanisms by which 25HC restricts Infection of nonenveloped viruses are unknown. We examined whether 25HC restricts Infection by mammalian Reovirus. Treatment with 25HC restricted Infection by Reovirus prototype strains type 1 Lang and type 3 Dearing. In contrast to Reovirus virions, 25HC did not restrict Infection by Reovirus infectious subvirion particles (ISVPs), which can penetrate either directly at the cell surface or in early endosomal membranes. Treatment with 25HC altered trafficking of Reovirus particles to late endosomes and delayed the kinetics of Reovirus uncoating. These results suggest that 25HC inhibits the efficiency of cellular entry of Reovirus virions, which may require specific endosomal membrane dynamics for efficient membrane penetration. IMPORTANCE The innate immune system is crucial for effective responses to viral Infection. Type I interferons, central components of innate immunity, induce expression of hundreds of ISGs; however, the mechanisms of action of these antiviral proteins are not well understood. CH25H, encoded by an ISG, represents a significant constituent of these cellular antiviral strategies, as its metabolic product, 25HC, can act in both an autocrine and a paracrine fashion to protect cells from Infection and has been shown to limit viral Infection in animal models. Further investigation into the mechanism of action of 25HC may inform novel antiviral therapies and influence the use of mammalian Reovirus in clinical trials as an oncolytic agent.
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retinoic acid inducible gene i and interferon β promoter stimulator 1 augment proapoptotic responses following mammalian Reovirus Infection via interferon regulatory factor 3
Journal of Biological Chemistry, 2007Co-Authors: Geoffrey H Holm, Pranav Danthi, Jennifer Zurney, Vanessa Tumilasci, Simon Leveille, John Hiscott, Barbara Sherry, Terence S. DermodyAbstract:During viral Infection, cells initiate antiviral responses to contain replication and inhibit virus spread. One protective mechanism involves activation of transcription factors interferon regulatory factor-3 (IRF-3) and NF-kappaB, resulting in secretion of the antiviral cytokine, interferon-beta. Another is induction of apoptosis, killing the host cell before virus disseminates. Mammalian Reovirus induces both interferon-beta and apoptosis, raising the possibility that both pathways are initiated by a common cellular sensor. We show here that Reovirus activates IRF-3 with kinetics that parallel the activation of NF-kappaB, a known mediator of Reovirus-induced apoptosis. Activation of IRF-3 requires functional retinoic acid inducible gene-I and interferon-beta promoter stimulator-1, but these intracellular sensors are dispensable for activation of NF-kappaB. Interferon-beta promoter stimulator-1 and IRF-3 are required for efficient apoptosis following Reovirus Infection, suggesting a common mechanism of antiviral cytokine induction and activation of the cell death response.
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retinoic acid inducible gene i and interferon β promoter stimulator 1 augment proapoptotic responses following mammalian Reovirus Infection via interferon regulatory factor 3
Journal of Biological Chemistry, 2007Co-Authors: Geoffrey H Holm, Pranav Danthi, Jennifer Zurney, Vanessa Tumilasci, Simon Leveille, John Hiscott, Barbara Sherry, Terence S. DermodyAbstract:During viral Infection, cells initiate antiviral responses to contain replication and inhibit virus spread. One protective mechanism involves activation of transcription factors interferon regulatory factor-3 (IRF-3) and NF-κB, resulting in secretion of the antiviral cytokine, interferon-β. Another is induction of apoptosis, killing the host cell before virus disseminates. Mammalian Reovirus induces both interferon-β and apoptosis, raising the possibility that both pathways are initiated by a common cellular sensor. We show here that Reovirus activates IRF-3 with kinetics that parallel the activation of NF-κB, a known mediator of Reovirus-induced apoptosis. Activation of IRF-3 requires functional retinoic acid inducible gene-I and interferon-β promoter stimulator-1, but these intracellular sensors are dispensable for activation of NF-κB. Interferon-β promoter stimulator-1 and IRF-3 are required for efficient apoptosis following Reovirus Infection, suggesting a common mechanism of antiviral cytokine induction and activation of the cell death response.
Kelly Urbanek - One of the best experts on this subject based on the ideXlab platform.
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cytidine monophosphate n acetylneuraminic acid synthetase and solute carrier family 35 member a1 are required for Reovirus binding and Infection
Journal of Virology, 2020Co-Authors: Kelly Urbanek, Danica M Sutherland, Robert C Orchard, Craig B Wilen, Jonathan J Knowlton, Pavithra AravamudhanAbstract:Engagement of cell-surface receptors by viruses is a critical determinant of viral tropism and disease. The Reovirus attachment protein, σ1, binds sialylated glycans and proteinaceous receptors to mediate Infection, but the specific requirements on different cell types are not entirely known. To identify host factors required for Reovirus-induced cell death, we conducted a CRISPR-knockout screen targeting over 20,000 genes in murine microglial BV2 cells. Candidate genes required for Reovirus to cause cell death were highly enriched for sialic acid synthesis and transport. Two of the top candidates identified, cytidine monophosphate N-acetylneuraminic acid synthetase (Cmas) and solute carrier family 35 member A1 (Slc35a1), promote sialic acid expression on the cell surface. Two Reovirus strains that differ in the capacity to bind sialic acid, T3SA+ and T3SA-, were used to evaluate Cmas and Slc35a1 as potential host genes required for Reovirus Infection. Following CRISPR-Cas9 disruption of either gene, cell-surface expression of sialic acid was diminished. These results correlated with decreased binding of strain T3SA+, which is capable of engaging sialic acid. Disruption of either gene did not alter the low-level binding of T3SA-, which does not engage sialic acid. Furthermore, infectivity of T3SA+ was diminished to levels of T3SA- in cells lacking Cmas and Slc35a1 by CRISPR ablation. However, exogenous expression of Cmas and Slc35a1 into the respective null cells restored sialic acid expression and T3SA+ binding and infectivity. These results demonstrate that Cmas and Slc35a1, which mediate cell-surface expression of sialic acid, are required in murine microglial cells for efficient Reovirus binding and Infection.IMPORTANCE Attachment factors and receptors are important determinants of dissemination and tropism during Reovirus-induced disease. In a CRISPR cell-survival screen, we discovered two genes, Cmas and Slc35a1, which encode proteins required for sialic acid expression on the cell surface, that mediate Reovirus Infection of microglial cells. This work elucidates host genes that render microglial cells susceptible to Reovirus Infection and expands current understanding of the receptors on microglial cells that are engaged by Reovirus. Such knowledge may lead to new strategies to selectively target microglial cells for oncolytic applications.
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cytidine monophosphate n acetylneuraminic acid synthetase and solute carrier family 35 member a1 are required for Reovirus binding and Infection
Journal of Virology, 2020Co-Authors: Kelly Urbanek, Danica M Sutherland, Robert C Orchard, Craig B Wilen, Jonathan J Knowlton, Pavithra AravamudhanAbstract:Engagement of cell surface receptors by viruses is a critical determinant of viral tropism and disease. The Reovirus attachment protein σ1 binds sialylated glycans and proteinaceous receptors to mediate Infection, but the specific requirements for different cell types are not entirely known. To identify host factors required for Reovirus-induced cell death, we conducted a CRISPR-knockout screen targeting over 20,000 genes in murine microglial BV2 cells. Candidate genes required for Reovirus to cause cell death were highly enriched for sialic acid synthesis and transport. Two of the top candidates identified, CMP N-acetylneuraminic acid synthetase (Cmas) and solute carrier family 35 member A1 (Slc35a1), promote sialic acid expression on the cell surface. Two Reovirus strains that differ in the capacity to bind sialic acid, T3SA+ and T3SA-, were used to evaluate Cmas and Slc35a1 as potential host genes required for Reovirus Infection. Following CRISPR-Cas9 disruption of either gene, cell surface expression of sialic acid was diminished. These results correlated with decreased binding of strain T3SA+, which is capable of engaging sialic acid. Disruption of either gene did not alter the low-level binding of T3SA-, which does not engage sialic acid. Furthermore, infectivity of T3SA+ was diminished to levels similar to those of T3SA- in cells lacking Cmas and Slc35a1 by CRISPR ablation. However, exogenous expression of Cmas and Slc35a1 into the respective null cells restored sialic acid expression and T3SA+ binding and infectivity. These results demonstrate that Cmas and Slc35a1, which mediate cell surface expression of sialic acid, are required in murine microglial cells for efficient Reovirus binding and Infection.IMPORTANCE Attachment factors and receptors are important determinants of dissemination and tropism during Reovirus-induced disease. In a CRISPR cell survival screen, we discovered two genes, Cmas and Slc35a1, which encode proteins required for sialic acid expression on the cell surface and mediate Reovirus Infection of microglial cells. This work elucidates host genes that render microglial cells susceptible to Reovirus Infection and expands current understanding of the receptors on microglial cells that are engaged by Reovirus. Such knowledge may lead to new strategies to selectively target microglial cells for oncolytic applications.
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cytidine monophosphate n acetylneuraminic acid synthetase and solute carrier family 35 member a1 are required for Reovirus binding and Infection
bioRxiv, 2020Co-Authors: Kelly Urbanek, Danica M Sutherland, Robert C Orchard, Craig B Wilen, Jonathan J Knowlton, Pavithra AravamudhanAbstract:ABSTRACT Engagement of cell-surface receptors by viruses is a critical determinant of viral tropism and disease. The Reovirus attachment protein, σ1, binds sialylated glycans and proteinaceous receptors to mediate Infection, but the specific requirements on different cell types are unknown. To identify host factors required for Reovirus-induced cell death, we conducted a CRISPR-knockout screen targeting over 20,000 genes in murine microglial BV2 cells. Candidate genes identified as required for Reovirus to cause cell death were highly enriched for sialic acid synthesis and transport. Two of the top candidates identified, cytidine monophosphate N-acetylneuraminic acid synthetase (Cmas) and solute carrier family 35 member A1 (Slc35a1), promote sialic acid expression on the cell surface. Two Reovirus strains differing in the capacity to bind sialic acid, T3SA+ and T3SA-, were used to evaluate Cmas and Slc35a1 as potential host genes required for Infection. Following CRISPR-Cas9 disruption of either gene, cell-surface expression of sialic acid was diminished. These results correlated with decreased binding of strain T3SA+, which is capable of engaging sialic acid. Disruption of either gene did not alter the low-level binding of T3SA-, which does not engage sialic acid. Infectivity of T3SA+ was diminished to levels of T3SA-in cells lacking Cmas and Slc35a1 by CRISPR ablation. However, exogenous expression of Cmas and Slc35a1 into the respective null cells restored sialic acid expression and T3SA+ binding and infectivity. These results demonstrate that Cmas and Slc35a1, which mediate cell-surface expression of sialic acid, are required in murine microglial cells for efficient Reovirus binding and Infection. IMPORTANCE Attachment factors and receptors are important determinants of dissemination and tropism during Reovirus-induced disease. In a CRISPR cell-survival screen, we discovered two genes, Cmas and Slc35a1, which encode proteins required for sialic acid expression on the cell surface, that mediate Reovirus Infection of microglial cells. This work elucidates host genes that render microglial cells susceptible to Reovirus Infection and expands current understanding of the receptors on microglial cells that are engaged by Reovirus. Such knowledge may lead to new strategies to selectively target microglial cells for oncolytic applications.
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murine norovirus Infection induces th1 inflammatory responses to dietary antigens
Cell Host & Microbe, 2018Co-Authors: Romain Bouziat, Scott B Biering, Elaine Kouame, Kishan Sangani, Soowon Kang, Jordan D Ernest, Mukund Varma, Judy J Brown, Kelly Urbanek, Terence S. DermodyAbstract:Summary Intestinal Reovirus Infection can trigger T helper 1 (TH1) immunity to dietary antigen, raising the question of whether other viruses can have a similar impact. Here we show that the acute CW3 strain of murine norovirus, but not the persistent CR6 strain, induces TH1 immunity to dietary antigen. This property of CW3 is dependent on its major capsid protein, a virulence determinant. Transcriptional profiling of mesenteric lymph nodes following Infection reveals an immunopathological signature that does not segregate with protective immunity but with loss of oral tolerance, in which interferon regulatory factor 1 is critical. These data show that viral capacity to trigger specific inflammatory pathways at sites where T cell responses to dietary antigens take place interferes with the development of tolerance to an oral antigen. Collectively, these data provide a foundation for the development of therapeutic strategies to prevent TH1-mediated complex immune disorders triggered by viral Infections.