NS1 Protein of 2009 Pandemic Influenza A Virus Inhibits Porcine NLRP3 Inflammasome-Mediated Interleukin-1 Beta Production by Suppressing ASC Ubiquitination
| Autor: | Qiang Liu, Hong-Su Park, GuanQun Liu, Shelby Landreth, Yan Zhou, Sathya N. Thulasi Raman |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Inflammasomes Swine Interleukin-1beta Immunology Viral Nonstructural Proteins Biology medicine.disease_cause Microbiology Virus Proinflammatory cytokine 03 medical and health sciences 0302 clinical medicine Orthomyxoviridae Infections Interleukin-1 beta production Virology NLR Family Pyrin Domain-Containing 3 Protein Influenza A virus medicine Animals Secretion Pandemics Swine Diseases Innate immune system integumentary system Ubiquitination Signal transducing adaptor protein Inflammasome Virus-Cell Interactions 3. Good health Cell biology CARD Signaling Adaptor Proteins 030104 developmental biology Insect Science 030215 immunology medicine.drug |
| Zdroj: | Journal of Virology. 92 |
| ISSN: | 1098-5514 0022-538X |
| Popis: | The inflammasome represents a molecular platform for innate immune regulation and controls proinflammatory cytokine production. The NLRP3 inflammasome is comprised of NLRP3, ASC, and procaspase-1. When the NLRP3 inflammasome is activated, it causes ASC speck formation and caspase-1 activation, resulting in the maturation of interleukin-1β (IL-1β). The NLRP3 inflammasome is regulated at multiple levels, with one level being posttranslational modification. Interestingly, ubiquitination of ASC has been reported to be indispensable for the activation of the NLRP3 inflammasome. Influenza A virus (IAV) infection induces NLRP3 inflammasome-dependent IL-1β secretion, which contributes to the host antiviral defense. However, IAVs have evolved multiple antagonizing mechanisms, one of which is executed by viral NS1 protein to suppress the NLRP3 inflammasome. In this study, we compared IL-1β production in porcine alveolar macrophages in response to IAV infection and found that the 2009 pandemic H1N1 induced less IL-1β than swine influenza viruses (SIVs). Further study revealed that the NS1 C terminus of pandemic H1N1 but not that of SIV was able to significantly inhibit NLRP3 inflammasome-mediated IL-1β production. This inhibitory function was attributed to impaired ASC speck formation and suppression of ASC ubiquitination. Moreover, we identified two target lysine residues, K110 and K140, which are essential for both porcine ASC ubiquitination and NLRP3 inflammasome-mediated IL-1β production. These results revealed a novel mechanism by which the NS1 protein of the 2009 pandemic H1N1 suppresses NLRP3 inflammasome activation. IMPORTANCE Influenza A virus (IAV) infection activates the NLRP3 inflammasome, resulting in the production of IL-1β, which contributes to the host innate immune response. ASC, an adaptor protein of NLRP3, forms specks that are critical for inflammasome activation. Here, we report that the NS1 C terminus of the 2009 pandemic H1N1 has functions to suppress porcine IL-1β production by inhibiting ASC speck formation and ASC ubiquitination. Furthermore, the ubiquitination sites on porcine ASC were identified. The information gained here may contribute to an in-depth understanding of porcine inflammasome activation and regulation in response to different IAVs, helping to further enhance our knowledge of innate immune responses to influenza virus infection in pigs. |
| Databáze: | OpenAIRE |
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