p58(IPK) suppresses NLRP3 inflammasome activation and IL-1β production via inhibition of PKR in macrophages.
p58(IPK) suppresses NLRP3 inflammasome activation and IL-1β production via inhibition of PKR in macrophages.
复制标题
DOI：
10.1038/srep25013
复制
发表时间：
2016-04-26
影响因子：
4.6
通讯作者：
Zhang SX
中科院分区：
文献类型：
--
作者：
Boriushkin E;Wang JJ;Li J;Bhatta M;Zhang SX
NLRP 3炎性体活化是从巨噬细胞活化和分泌促炎细胞因子如IL-1β的关键信号传导事件。p58 IPK是一种分子伴侣，通过抑制包括双链RNA依赖性蛋白激酶（PKR）在内的eIF-2α激酶来调节蛋白质稳态，PKR最近被认为与炎性小体激活有关。在此，我们研究了p58 IPK在巨噬细胞中TLR 4信号传导和炎性小体激活中的作用。从p58 IPK敲除（KO）和野生型（WT）小鼠中分离原代骨髓衍生的巨噬细胞（BMDM），并用脂多糖（LPS）和ATP处理以激活TLR 4信号传导并刺激炎性小体激活。与WT巨噬细胞相比，p58 IPK缺陷型细胞表现出PKR、NF-κB和JNK的显著更强的活化以及促炎基因TNF-α和IL-1β的更高表达。巧合的是，p58 IPK缺失增强了NLRP 3-炎性体活化，这通过增强的半胱天冬酶1切割和增加的IL-1β成熟和分泌来指示。用特异性PKR抑制剂或p58 IPK过表达预处理可显著抑制p58 IPK无效巨噬细胞炎性小体活化和IL-1β分泌的变化。免疫沉淀实验证实p58 IPK与PKR结合，而与其它TLR 4下游信号分子不结合。总之，这些结果表明p58 IPK在调节巨噬细胞中炎性小体活化和IL-1β分泌中的新的和关键的作用。
The NLRP3 inflammasome activation is a key signaling event for activation and secretion of pro-inflammatory cytokines such as IL-1β from macrophages. p58IPK is a molecular chaperone that regulates protein homeostasis through inhibiting eIF-2α kinases including double-stranded RNA–dependent protein kinase (PKR), which has been recently implicated in inflammasome activation. Herein we investigate the role of p58IPK in TLR4 signaling and inflammasome activation in macrophages. Primary bone marrow-derived macrophages (BMDM) was isolated from p58IPK knockout (KO) and wildtype (WT) mice and treated with lipopolysaccharide (LPS) and ATP to activate TLR4 signaling and stimulate inflammasome activation. Compared to WT macrophages, p58IPK deficient cells demonstrated significantly stronger activation of PKR, NF-κB, and JNK and higher expression of pro-inflammatory genes TNF-α and IL-1β. Coincidently, p58IPK deletion intensified NLRP3-inflammasome activation indicated by enhanced caspase 1 cleavage and increased IL-1β maturation and secretion. Pretreatment with specific PKR inhibitor or overexpression of p58IPK largely abolished the changes in inflammasome activation and IL-1β secretion in p58IPK null macrophages. Furthermore, immunoprecipitation assay confirmed the binding of p58IPK with PKR, but not other TLR4 downstream signaling molecules. Collectively, these results suggest a novel and crucial role of p58IPK in regulation of inflammasome activation and IL-1β secretion in macrophages.