- Email: [email protected]
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Abstract / Cytokine 63 (2013) 243–314
correlates with high cytokine levels in Ebolavirus infection. Currently we are investigating which cellular signaling pathways are involved in the observed differential cytokine induction in EBOV versus RESTV infection. http://dx.doi.org/10.1016/j.cyto.2013.06.192
190 Group-2 innate lymphoid cell/T cell interactions in helminth expulsion Christopher J. Oliphant a, See Heng Wong a,1, Jennifer A. Walker a, You Yi Hwang a, Jillian L. Barlow a, Emily Hams d, Padraic G. Fallon b,c,d, Andrew N.J. McKenzie a, a MRC Laboratory of Molecular Biology, Cambridge, UK, b Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland, c National Children’s Research Centre, Dublin, Ireland, d Institute of Molecular Medicine, Trinity College Dublin, Dublin 2, Ireland Group-2 innate lymphoid cells (ILC2) are a recently discovered subset of innate lymphocytes that are essential for both the protective and detrimental type-2 immune responses associated with helminth infections and allergens, respectively. ILC2 arise rapidly in response to the epithelial cytokines interleukin (IL)-25 and IL33, and are typically characterised by the release of the type-2 associated cytokines, IL-13 and IL-5. Previous data from our laboratory have demonstrated that IL-13 expression by ILC2 is essential for the successful clearance of the helminth parasite, Nippostrongylus brasiliensis. Interestingly, we also noted that an impaired ability of Rag2-deficient mice to expel N.brasiliensis correlated with a failure to maintain ILC2 beyond the first few days of infection. This finding suggested that proliferation, migration and/or prolonged survival of ILC2 are highly dependent on a dialogue between ILC2 and either with T or B cells. However, previous studies have shown that B cells, unlike T cells, are dispensable for helminth clearance leading us to examine the mediators associated with ILC2 and T cells in N. brasiliensis infections. Using in vitro co-culture systems we demonstrate that interactions with T cells are highly important for the expansion of ILC2, and their expression of IL-13 and IL-5. Furthermore, we show how these molecular interactions between ILC2 and T cells are important for the efficient expulsion of N. brasiliensis in vivo. Together our data demonstrate that ILC2/T cell interactions are a previously unappreciated mechanism for the initiation and maintenance of type-2 immunity. http://dx.doi.org/10.1016/j.cyto.2013.06.193
191 Difference in the activation of IFN gene expression in response to influenza A and B virus entry Pamela Österlund, Sanna Mäkelä, Veera Arilahti, Ilkka Julkunen, Virology Unit, National Institute for Health and Welfare, Helsinki, Finland Activation of interferon (IFN) system, which is triggered largely by the recognition of viral nucleic acids, is one of the most important host defense reactions against viral infection. Both influenza A and B viruses have a negative strand RNA genome and they possess significant structural similarities. However, influenza A and B viruses are evolutionally diverged with complete genetic incompatibility. We analysed the mechanisms of activation of innate immunity during the infection with type A and B influenza viruses in human dendritic cells. We have previously shown that IFN responses are induced significantly faster in cells infected with influenza B virus than type A virus. We demonstrated that influenza A virus infection activates IFN responses only after the viral RNA (vRNA) synthesis, whereas influenza B virus induces IFN responses even if the infectivity of the virus is destroyed by UV treatment. Thus, initial viral transcription, replication and viral protein synthesis are not required for influenza B virus-induced antiviral responses. Furthermore, we observed that the early induction of IFN gene expression by influenza B virus is mediated by multiple signalling pathways with strong dependency on NF-jB transcription factor in addition to IRF3. The disturbance of endosomal acidification prevented IFN induction suggesting cytosolic recognition of incoming influenza B virus structures to be important in regulating IFN gene expression. Moreover, influenza B virus NP located in the nuclei already at 15 min postinfection whereas the NP from incoming type A virus was found in nuclear fractions at later time points of infection and in significantly lesser extent. Collectively, our data provides new evidence of the mechanisms of influenza B virus recognition by the host cell providing new insights in the understanding of the pathogenesis of different influenza virus types. http://dx.doi.org/10.1016/j.cyto.2013.06.194
1
Present address: MedImmune, Milstein Building, Cambridge, UK.
192 The functional analysis of RIG-I-inducible microRNA Ryota Ouda a, Koji Onomoto b, Kiyohiro Takahasi a, Hiroki Kato a, Mitstoshi Yoneyama b, Takashi Fujita a, a Laboratory of Molecular Genetics, Institute for Virus Research, Kyoto University, Japan, b Medical Mycology Research Center, Chiba University, Japan In mammals, viral infections are detected by innate immune receptors, including Toll-like receptor (TLR) and retinoic acid inducible gene I (RIG-I)-like receptor (RLR), which activate the type I interferon (IFN) system. IFN essentially activates genes encoding antiviral proteins that inhibit various steps of viral replication as well as facilitate the subsequent activation of acquired immune responses. In this study, we investigated the expression of non-coding RNA upon viral infection or RLR activation. Using a microarray, we identified several microRNAs (miRNAs) specifically induced by the activation of RLR signaling. According to miRNA microarray, miR423-3p was one of the RIG-I-inducible miRNAs. We found that overexpression of miR-423-3p augments expression level of IFN-b upon viral infection. Conversely, introduction of anti-miR-423-3p suppressed expression level of IFN-b upon viral infection. To explore the possible target genes of miR-423-3p, we used three different databases (Target Scan, Micro Cosm, microRNA.org). Among these database, only one gene, Poly(A)-binding protein 1 (PABP1), was overlapped. PABP1 is known as one of the components of stress granules (SGs). Previously we have reported that SGs are important loci to mediate RIG-I signaling. Knockdown and overexpression experiment of PABP1 revealed enhanced and suppressed production of IFN-b respectively. These results suggest that PABP1 acts as a negative regulator of RIG-I mediate signaling and the function of PABP1 is finely regulated by miR-423-3p. http://dx.doi.org/10.1016/j.cyto.2013.06.195
193 Type I interferon treatment inhibits the formation of RNA virus replicationassociated membrane structures Diede Oudshoorn a, Corrine Beugeling a, Ronald W.A.L. Limpens b, Jochem Pronk a, Jessica Ruinard a, Eric J. Snijder a, Montserrat Bárcena b, Marjolein Kikkert a, a Department of Medical Microbiology, Section Molecular Virology, Leiden University Medical Center, Leiden, The Netherlands, b Department of Molecular Cell Biology, Section Electron Microscopy, Leiden University Medical Center, Leiden, The Netherlands The antiviral innate immune response is built around the prompt recognition of pathogen-associated molecular patterns (PAMPs) and the subsequent inhibition of the replication of the associated virus until the adaptive immune response is activated for ultimate clearance of the virus. All plus-stranded RNA viruses hijack intracellular host membranes to form elaborate virus-induced membrane modifications, such as the network of interconnected ER-derived double membrane vesicles formed by corona- and arteriviruses. These membrane structures not only accommodate the viral replication machinery, but also devastate the interior of the cell during infection. We hypothesized that the innate immune system may have ways to directly counteract the formation of these virus-induced structures and/or recognize the virally modified membranes as PAMPs. Ectopic expression of several arterivirus non-structural proteins (nsps) results in the formation of membrane structures similar to those observed during infection, in the absence of replicating virus. Using large scale 2D electron microscopy mosaic maps of cells expressing arterivirus nsp2–3, we found that type I interferon pre-treatment significantly reduced the formation of virus-associated membrane modifications, while the expression level and subcellular localization of the nsps was not affected. This suggests a direct inhibitory effect of type I interferon and/or interferon-stimulated genes on the formation of virus-induced membrane modifications. The underlying mechanism and the innate immune factors involved remain to be elucidated and future work will also aim to determine whether virus-induced membrane modifications function as PAMPs. http://dx.doi.org/10.1016/j.cyto.2013.06.196
194 IRF8 regulates autophagy and activates microglia to exacerbate neuroinflammation Keiko Ozato a, Ryusuke Yoshimi a, Yuko Yoshida a, Monica Gupta a, Hiroaki Yoshii a, Jeeva Munasinghe b, Olga Maximova c, Huabao Xiong d, Hongsheng Wang e, Herbert C. Morse e, a Program in Genomics of Differentiation, NICHD, National Institutes of Health, Bethesda, MD, USA, b Laboratory of Molecular Imaging, NINDS, National Institutes of Health, Bethesda, MD, USA, c Laboratory of Infectious Diseases, National Institutes of
Abstract / Cytokine 63 (2013) 243–314
correlates with high cytokine levels in Ebolavirus infection. Currently we are investigating which cellular signaling pathways are involved in the observed differential cytokine induction in EBOV versus RESTV infection. http://dx.doi.org/10.1016/j.cyto.2013.06.192
190 Group-2 innate lymphoid cell/T cell interactions in helminth expulsion Christopher J. Oliphant a, See Heng Wong a,1, Jennifer A. Walker a, You Yi Hwang a, Jillian L. Barlow a, Emily Hams d, Padraic G. Fallon b,c,d, Andrew N.J. McKenzie a, a MRC Laboratory of Molecular Biology, Cambridge, UK, b Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland, c National Children’s Research Centre, Dublin, Ireland, d Institute of Molecular Medicine, Trinity College Dublin, Dublin 2, Ireland Group-2 innate lymphoid cells (ILC2) are a recently discovered subset of innate lymphocytes that are essential for both the protective and detrimental type-2 immune responses associated with helminth infections and allergens, respectively. ILC2 arise rapidly in response to the epithelial cytokines interleukin (IL)-25 and IL33, and are typically characterised by the release of the type-2 associated cytokines, IL-13 and IL-5. Previous data from our laboratory have demonstrated that IL-13 expression by ILC2 is essential for the successful clearance of the helminth parasite, Nippostrongylus brasiliensis. Interestingly, we also noted that an impaired ability of Rag2-deficient mice to expel N.brasiliensis correlated with a failure to maintain ILC2 beyond the first few days of infection. This finding suggested that proliferation, migration and/or prolonged survival of ILC2 are highly dependent on a dialogue between ILC2 and either with T or B cells. However, previous studies have shown that B cells, unlike T cells, are dispensable for helminth clearance leading us to examine the mediators associated with ILC2 and T cells in N. brasiliensis infections. Using in vitro co-culture systems we demonstrate that interactions with T cells are highly important for the expansion of ILC2, and their expression of IL-13 and IL-5. Furthermore, we show how these molecular interactions between ILC2 and T cells are important for the efficient expulsion of N. brasiliensis in vivo. Together our data demonstrate that ILC2/T cell interactions are a previously unappreciated mechanism for the initiation and maintenance of type-2 immunity. http://dx.doi.org/10.1016/j.cyto.2013.06.193
191 Difference in the activation of IFN gene expression in response to influenza A and B virus entry Pamela Österlund, Sanna Mäkelä, Veera Arilahti, Ilkka Julkunen, Virology Unit, National Institute for Health and Welfare, Helsinki, Finland Activation of interferon (IFN) system, which is triggered largely by the recognition of viral nucleic acids, is one of the most important host defense reactions against viral infection. Both influenza A and B viruses have a negative strand RNA genome and they possess significant structural similarities. However, influenza A and B viruses are evolutionally diverged with complete genetic incompatibility. We analysed the mechanisms of activation of innate immunity during the infection with type A and B influenza viruses in human dendritic cells. We have previously shown that IFN responses are induced significantly faster in cells infected with influenza B virus than type A virus. We demonstrated that influenza A virus infection activates IFN responses only after the viral RNA (vRNA) synthesis, whereas influenza B virus induces IFN responses even if the infectivity of the virus is destroyed by UV treatment. Thus, initial viral transcription, replication and viral protein synthesis are not required for influenza B virus-induced antiviral responses. Furthermore, we observed that the early induction of IFN gene expression by influenza B virus is mediated by multiple signalling pathways with strong dependency on NF-jB transcription factor in addition to IRF3. The disturbance of endosomal acidification prevented IFN induction suggesting cytosolic recognition of incoming influenza B virus structures to be important in regulating IFN gene expression. Moreover, influenza B virus NP located in the nuclei already at 15 min postinfection whereas the NP from incoming type A virus was found in nuclear fractions at later time points of infection and in significantly lesser extent. Collectively, our data provides new evidence of the mechanisms of influenza B virus recognition by the host cell providing new insights in the understanding of the pathogenesis of different influenza virus types. http://dx.doi.org/10.1016/j.cyto.2013.06.194
1
Present address: MedImmune, Milstein Building, Cambridge, UK.
192 The functional analysis of RIG-I-inducible microRNA Ryota Ouda a, Koji Onomoto b, Kiyohiro Takahasi a, Hiroki Kato a, Mitstoshi Yoneyama b, Takashi Fujita a, a Laboratory of Molecular Genetics, Institute for Virus Research, Kyoto University, Japan, b Medical Mycology Research Center, Chiba University, Japan In mammals, viral infections are detected by innate immune receptors, including Toll-like receptor (TLR) and retinoic acid inducible gene I (RIG-I)-like receptor (RLR), which activate the type I interferon (IFN) system. IFN essentially activates genes encoding antiviral proteins that inhibit various steps of viral replication as well as facilitate the subsequent activation of acquired immune responses. In this study, we investigated the expression of non-coding RNA upon viral infection or RLR activation. Using a microarray, we identified several microRNAs (miRNAs) specifically induced by the activation of RLR signaling. According to miRNA microarray, miR423-3p was one of the RIG-I-inducible miRNAs. We found that overexpression of miR-423-3p augments expression level of IFN-b upon viral infection. Conversely, introduction of anti-miR-423-3p suppressed expression level of IFN-b upon viral infection. To explore the possible target genes of miR-423-3p, we used three different databases (Target Scan, Micro Cosm, microRNA.org). Among these database, only one gene, Poly(A)-binding protein 1 (PABP1), was overlapped. PABP1 is known as one of the components of stress granules (SGs). Previously we have reported that SGs are important loci to mediate RIG-I signaling. Knockdown and overexpression experiment of PABP1 revealed enhanced and suppressed production of IFN-b respectively. These results suggest that PABP1 acts as a negative regulator of RIG-I mediate signaling and the function of PABP1 is finely regulated by miR-423-3p. http://dx.doi.org/10.1016/j.cyto.2013.06.195
193 Type I interferon treatment inhibits the formation of RNA virus replicationassociated membrane structures Diede Oudshoorn a, Corrine Beugeling a, Ronald W.A.L. Limpens b, Jochem Pronk a, Jessica Ruinard a, Eric J. Snijder a, Montserrat Bárcena b, Marjolein Kikkert a, a Department of Medical Microbiology, Section Molecular Virology, Leiden University Medical Center, Leiden, The Netherlands, b Department of Molecular Cell Biology, Section Electron Microscopy, Leiden University Medical Center, Leiden, The Netherlands The antiviral innate immune response is built around the prompt recognition of pathogen-associated molecular patterns (PAMPs) and the subsequent inhibition of the replication of the associated virus until the adaptive immune response is activated for ultimate clearance of the virus. All plus-stranded RNA viruses hijack intracellular host membranes to form elaborate virus-induced membrane modifications, such as the network of interconnected ER-derived double membrane vesicles formed by corona- and arteriviruses. These membrane structures not only accommodate the viral replication machinery, but also devastate the interior of the cell during infection. We hypothesized that the innate immune system may have ways to directly counteract the formation of these virus-induced structures and/or recognize the virally modified membranes as PAMPs. Ectopic expression of several arterivirus non-structural proteins (nsps) results in the formation of membrane structures similar to those observed during infection, in the absence of replicating virus. Using large scale 2D electron microscopy mosaic maps of cells expressing arterivirus nsp2–3, we found that type I interferon pre-treatment significantly reduced the formation of virus-associated membrane modifications, while the expression level and subcellular localization of the nsps was not affected. This suggests a direct inhibitory effect of type I interferon and/or interferon-stimulated genes on the formation of virus-induced membrane modifications. The underlying mechanism and the innate immune factors involved remain to be elucidated and future work will also aim to determine whether virus-induced membrane modifications function as PAMPs. http://dx.doi.org/10.1016/j.cyto.2013.06.196
194 IRF8 regulates autophagy and activates microglia to exacerbate neuroinflammation Keiko Ozato a, Ryusuke Yoshimi a, Yuko Yoshida a, Monica Gupta a, Hiroaki Yoshii a, Jeeva Munasinghe b, Olga Maximova c, Huabao Xiong d, Hongsheng Wang e, Herbert C. Morse e, a Program in Genomics of Differentiation, NICHD, National Institutes of Health, Bethesda, MD, USA, b Laboratory of Molecular Imaging, NINDS, National Institutes of Health, Bethesda, MD, USA, c Laboratory of Infectious Diseases, National Institutes of