Mycobacterium tuberculosis protein ESAT-6 is a potent activator of the NLRP3/ASC inflammasome
Mycobacterium tuberculosis protein ESAT-6 is a potent activator of the NLRP3/ASC inflammasome
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DOI：
10.1111/j.1462-5822.2010.01450.x
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发表时间：
2010-08-01
影响因子：
3.4
通讯作者：
Anes, Elsa
中科院分区：
文献类型：
--
作者：
Mishra, Bibhuti B.;Moura-Alves, Pedro;Anes, Elsa
白细胞介素-1 β（IL-1 β）是炎症和宿主对感染反应的最重要介质之一。结核分枝杆菌（Mycobacterium tuberculosis，Mtb）是人类结核病的病原体，其在感染部位诱导IL-1 β分泌，但其潜在机制尚不清楚。在这项工作中，我们表明，结核分枝杆菌感染的巨噬细胞刺激caspase-1活性，促进IL-1 β的分泌。这种刺激需要表达功能性ESX-1分泌系统的活细胞内细菌。ESAT-6是一种与膜损伤有关的ESX-1底物，对于胱天蛋白酶-1活化和IL-1 β分泌是必要和充分的。ESAT-6促进其他免疫刺激剂如AG 85进入巨噬细胞胞质溶胶，表明这种蛋白质可能主要通过扰乱宿主细胞膜来促进胱天蛋白酶-1活化。使用基于shRNA的高通量筛选，我们发现许多NOD样受体（NLR）和含CARD结构域的蛋白（CARD）对于Mtb感染后的IL-1 β分泌是重要的。最重要的是，NLRP 3、ASC和半胱天冬酶-1形成感染诱导的炎性体复合物，其对于IL-1 β分泌是必需的。总之，我们发现NLRP 3炎性小体对Mtb感染的识别需要细菌毒力因子ESAT-6的活性，随后的IL-1 β应答受许多NLR/CARD蛋白的调节。
P>Interleukin-1 beta (IL-1 beta) represents one of the most important mediators of inflammation and host responses to infection. Mycobacterium tuberculosis (Mtb), the causative agent of human tuberculosis, induces IL-1 beta secretion at the site of infection, but the underlying mechanism(s) are poorly understood. In this work we show that Mtb infection of macrophages stimulates caspase-1 activity and promotes the secretion of IL-1 beta. This stimulation requires live intracellular bacteria expressing a functional ESX-1 secretion system. ESAT-6, an ESX-1 substrate implicated in membrane damage, is both necessary and sufficient for caspase-1 activation and IL-1 beta secretion. ESAT-6 promotes the access of other immunostimulatory agents such as AG85 into the macrophage cytosol, indicating that this protein may contribute to caspase-1 activation largely by perturbing host cell membranes. Using a high-throughput shRNA-based screen we found that numerous NOD-like receptors (NLRs) and CARD domain-containing proteins (CARDs) were important for IL-1 beta secretion upon Mtb infection. Most importantly, NLRP3, ASC and caspase-1 form an infection-inducible inflammasome complex that is essential for IL-1 beta secretion. In summary, we show that recognition of Mtb infection by the NLRP3 inflammasome requires the activity of the bacterial virulence factor ESAT-6, and the subsequent IL-1 beta response is regulated by a number of NLR/CARD proteins.