RESUMO
Interleukin 1 beta (IL-1 beta) is a potent proinflammatory factor during viral infection. Its production is tightly controlled by transcription of Il1b dependent on the transcription factor NF-kappaB and subsequent processing of pro-IL-1 beta by an inflammasome. However, the sensors and mechanisms that facilitate RNA virus-induced production of IL-1 beta are not well defined. Here we report a dual role for the RNA helicase RIG-I in RNA virus-induced proinflammatory responses. Whereas RIG-I-mediated activation of NF-kappaB required the signaling adaptor MAVS and a complex of the adaptors CARD9 and Bcl-10, RIG-I also bound to the adaptor ASC to trigger caspase-1-dependent inflammasome activation by a mechanism independent of MAVS, CARD9 and the Nod-like receptor protein NLRP3. Our results identify the CARD9-Bcl-10 module as an essential component of the RIG-I-dependent proinflammatory response and establish RIG-I as a sensor able to activate the inflammasome in response to certain RNA viruses.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , RNA Helicases DEAD-box/metabolismo , Inflamação/fisiopatologia , Interleucina-1beta/metabolismo , Vírus de RNA/fisiologia , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas Adaptadoras de Sinalização CARD , Caspase 1/metabolismo , Linhagem Celular , Células Cultivadas , Proteína DEAD-box 58 , RNA Helicases DEAD-box/genética , Vírus da Encefalomiocardite/imunologia , Vírus da Encefalomiocardite/fisiologia , Ativação Enzimática , Ensaio de Imunoadsorção Enzimática , Interações Hospedeiro-Patógeno , Humanos , Immunoblotting , Inflamação/imunologia , Inflamação/virologia , Helicase IFIH1 Induzida por Interferon , Camundongos , Camundongos Knockout , Modelos Biológicos , Infecções por Vírus de RNA/imunologia , Infecções por Vírus de RNA/fisiopatologia , Infecções por Vírus de RNA/virologia , Vírus de RNA/imunologia , Vírus da Estomatite Vesicular Indiana/imunologia , Vírus da Estomatite Vesicular Indiana/fisiologia , Proteína bcl-X/genética , Proteína bcl-X/metabolismoRESUMO
Novel vaccination strategies against Mycobacterium tuberculosis (MTB) are urgently needed. The use of recombinant MTB antigens as subunit vaccines is a promising approach, but requires adjuvants that activate antigen-presenting cells (APCs) for elicitation of protective immunity. The mycobacterial cord factor Trehalose-6,6-dimycolate (TDM) and its synthetic analogue Trehalose-6,6-dibehenate (TDB) are effective adjuvants in combination with MTB subunit vaccine candidates in mice. However, it is unknown which signaling pathways they engage in APCs and how these pathways are coupled to the adaptive immune response. Here, we demonstrate that these glycolipids activate macrophages and dendritic cells (DCs) via Syk-Card9-Bcl10-Malt1 signaling to induce a specific innate activation program distinct from the response to Toll-like receptor (TLR) ligands. APC activation by TDB and TDM was independent of the C-type lectin receptor Dectin-1, but required the immunoreceptor tyrosine-based activation motif-bearing adaptor protein Fc receptor gamma chain (FcRgamma). In vivo, TDB and TDM adjuvant activity induced robust combined T helper (Th)-1 and Th-17 T cell responses to a MTB subunit vaccine and partial protection against MTB challenge in a Card9-dependent manner. These data provide a molecular basis for the immunostimulatory activity of TDB and TDM and identify the Syk-Card9 pathway as a rational target for vaccine development against tuberculosis.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Imunidade Inata/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Tirosina Quinases/genética , Receptores de IgE/genética , Vacinas contra a Tuberculose/imunologia , Adjuvantes Imunológicos/farmacologia , Animais , Proteína 10 de Linfoma CCL de Células B , Proteínas Adaptadoras de Sinalização CARD , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Caspases/genética , Citocinas/genética , Citocinas/metabolismo , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Glicolipídeos/imunologia , Glicolipídeos/farmacologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Pulmão/imunologia , Pulmão/microbiologia , Linfonodos/imunologia , Linfonodos/microbiologia , Ativação de Macrófagos/efeitos dos fármacos , Ativação de Macrófagos/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa , Proteínas de Neoplasias/genética , Transdução de Sinais/imunologia , Quinase Syk , Linfócitos T Auxiliares-Indutores/efeitos dos fármacos , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Vacinas contra a Tuberculose/administração & dosagem , Vacinas contra a Tuberculose/genética , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/microbiologia , Tuberculose Pulmonar/prevenção & controle , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/imunologiaRESUMO
Fungal infections are increasing worldwide due to the marked rise in immunodeficiencies including AIDS; however, immune responses to fungi are poorly understood. Dectin-1 is the major mammalian pattern recognition receptor for the fungal component zymosan. Dectin-1 represents the prototype of innate non-Toll-like receptors (TLRs) containing immunoreceptor tyrosine-based activation motifs (ITAMs) related to those of adaptive antigen receptors. Here we identify Card9 as a key transducer of Dectin-1 signalling. Although being dispensable for TLR/MyD88-induced responses, Card9 controls Dectin-1-mediated myeloid cell activation, cytokine production and innate anti-fungal immunity. Card9 couples to Bcl10 and regulates Bcl10-Malt1-mediated NF-kappaB activation induced by zymosan. Yet, Card9 is dispensable for antigen receptor signalling that uses Carma1 as a link to Bcl10-Malt1. Thus, our results define a novel innate immune pathway and indicate that evolutionarily distinct ITAM receptors in innate and adaptive immune cells use diverse adaptor proteins to engage selectively the conserved Bcl10-Malt1 module.