Encephalomyocarditis virus viroporin 2B activates NLRP3 inflammasome.
Encephalomyocarditis virus viroporin 2B activates NLRP3 inflammasome.
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DOI：
10.1371/journal.ppat.1002857
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发表时间：
2012
期刊：
影响因子：
6.7
通讯作者：
Ichinohe T
中科院分区：
文献类型：
--
作者：
Ito M;Yanagi Y;Ichinohe T
Nod-like receptor（NLR）包括细胞内模式识别受体的大家族。NLR家族的成员组装成大的多蛋白复合物，称为炎性小体。NLR家族，含有pyrin结构域的3（NLRP 3）由一组不同的分子和信号触发，并形成NLRP 3炎性体。最近的研究表明，DNA和RNA病毒都刺激NLRP 3炎性小体，导致在半胱天冬酶-1活化后分泌白细胞介素1 β（IL-1β）和IL-18。我们以前证明了流感病毒的质子选择性离子通道M2蛋白激活NLRP 3炎性小体。然而，NLRP 3识别病毒感染的确切机制仍有待确定。在这里，我们证明，脑心肌炎病毒（EMCV），家庭小RNA病毒科的正链RNA病毒，激活小鼠树突状细胞和巨噬细胞中的NLRP 3炎性小体。尽管用来自EMCV病毒粒子或EMCV感染的细胞的RNA转染诱导巨噬细胞中I型干扰素的稳健表达，但其不能刺激IL-1β的分泌。相反，EMCV病毒孔蛋白2B足以引起脂多糖引发的巨噬细胞中的炎性小体活化。虽然未转染或用编码EMCV非结构蛋白2A或2C的基因转染的细胞在整个细胞质中均匀表达NLRP 3，但在用编码EMCV 2B或流感病毒M2蛋白的基因转染的细胞中，NLRP 3被重新分布到核周空间。其他小RNA病毒、脊髓灰质炎病毒和肠道病毒71的2B蛋白也引起NLRP 3的再分布。EMCV诱导的NLRP 3炎性小体激活中，细胞内Ca 2+水平升高是重要的，但线粒体活性氧和溶酶体组织蛋白酶B无此作用。螯合细胞外Ca 2+并不减少病毒诱导的IL-1β分泌。这些结果表明，EMCV通过刺激Ca 2+从细胞内储存流到胞质溶胶来激活NLRP 3炎性小体，并突出了病毒孔蛋白（跨膜孔形成病毒蛋白）在病毒诱导的NLRP 3炎性小体激活中的重要性。先天免疫系统是抵御入侵病原体的第一道防线，不仅在感染的早期阶段限制微生物复制，而且在启动和协调抗原特异性适应性免疫应答中发挥关键作用。针对病毒的先天性免疫应答通常依赖于宿主模式识别受体如Toll样受体和胞质解旋酶对病毒核酸的识别。此外，最近的研究表明，某些病毒激活NLRP 3炎性体，一种含有细胞内模式识别受体NLRP 3的多蛋白复合物，其反过来诱导促炎细胞因子的分泌。我们先前已经揭示了NLRP 3炎性体在流感病毒的先天识别中的作用，其中需要流感病毒质子选择性离子通道M2蛋白，而不是病毒RNA。在这里，我们证明了另一种RNA病毒，脑心肌炎病毒（EMCV），也激活NLRP 3炎性小体在病毒RNAindependent方式。相反，EMCV病毒孔蛋白2B，其参与Ca 2+从细胞内储存流到细胞质中，激活NLRP 3炎性体。我们的研究结果突出了病毒孔蛋白，病毒编码的跨膜孔形成蛋白，在识别病毒感染的NLRP 3的重要性。
Nod-like receptors (NLRs) comprise a large family of intracellular pattern- recognition receptors. Members of the NLR family assemble into large multiprotein complexes, termed the inflammasomes. The NLR family, pyrin domain-containing 3 (NLRP3) is triggered by a diverse set of molecules and signals, and forms the NLRP3 inflammasome. Recent studies have indicated that both DNA and RNA viruses stimulate the NLRP3 inflammasome, leading to the secretion of interleukin 1 beta (IL-1β) and IL-18 following the activation of caspase-1. We previously demonstrated that the proton-selective ion channel M2 protein of influenza virus activates the NLRP3 inflammasome. However, the precise mechanism by which NLRP3 recognizes viral infections remains to be defined. Here, we demonstrate that encephalomyocarditis virus (EMCV), a positive strand RNA virus of the family Picornaviridae, activates the NLRP3 inflammasome in mouse dendritic cells and macrophages. Although transfection with RNA from EMCV virions or EMCV-infected cells induced robust expression of type I interferons in macrophages, it failed to stimulate secretion of IL-1β. Instead, the EMCV viroporin 2B was sufficient to cause inflammasome activation in lipopolysaccharide-primed macrophages. While cells untransfected or transfected with the gene encoding the EMCV non-structural protein 2A or 2C expressed NLRP3 uniformly throughout the cytoplasm, NLRP3 was redistributed to the perinuclear space in cells transfected with the gene encoding the EMCV 2B or influenza virus M2 protein. 2B proteins of other picornaviruses, poliovirus and enterovirus 71, also caused the NLRP3 redistribution. Elevation of the intracellular Ca2+ level, but not mitochondrial reactive oxygen species and lysosomal cathepsin B, was important in EMCV-induced NLRP3 inflammasome activation. Chelation of extracellular Ca2+ did not reduce virus-induced IL-1β secretion. These results indicate that EMCV activates the NLRP3 inflammasome by stimulating Ca2+ flux from intracellular storages to the cytosol, and highlight the importance of viroporins, transmembrane pore-forming viral proteins, in virus-induced NLRP3 inflammasome activation. The innate immune system, the first line of defense against invading pathogens, plays a key role not only in limiting microbe replications at early stages of infection, but also in initiating and orchestrating antigen-specific adaptive immune responses. The innate immune responses against viruses usually rely on recognition of viral nucleic acids by host pattern-recognition receptors such as Toll-like receptors and cytosolic helicases. In addition, recent studies have indicated that certain viruses activate the NLRP3 inflammasome, a multiprotein complex containing the intracellular pattern-recognition receptor NLRP3, which in turn induces secretion of proinflammatory cytokines. We have previously revealed the role of the NLRP3 inflammasome in innate recognition of influenza virus, in which the influenza virus proton-selective ion channel M2 protein, but not viral RNA, is required. Here, we demonstrate that another RNA virus, encephalomyocarditis virus (EMCV), also activates the NLRP3 inflammasome in a viral RNAindependent manner. Instead, the EMCV viroporin 2B, which is involved in Ca2+ flux from intracellular storages into the cytosol, activates the NLRP3 inflammasome. Our results highlight the importance of viroporins, virusencoded transmembrane pore-forming proteins, in recognition of virus infections by NLRP3.
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DOI：
10.1038/nri2851
发表时间：
2010-10
期刊：
Nature reviews. Immunology
影响因子：
--
作者：
通讯作者：
--
影响因子：
64.5
作者：
Gurcel, Laure;Abrami, Laurence;van der Goot, F. Gisou
通讯作者：
van der Goot, F. Gisou
DOI：
10.1016/j.bbamcr.2006.09.025
发表时间：
2006-11-01
影响因子：
5.1
作者：
Chami, Mounia;Oules, Benedicte;Paterlini-Brechot, Patrizia
通讯作者：
Paterlini-Brechot, Patrizia
影响因子：
5.4
作者：
de Jong, Arjan S.;de Mattia, Fabrizio;van Kuppeveld, Frank J. M.
通讯作者：
van Kuppeveld, Frank J. M.
影响因子：
3.8
作者：
Brask, J;Owe-Larsson, B;Kristensson, K
通讯作者：
Kristensson, K