Alarmin HNP-1 promotes pyroptosis and IL-1β release through different roles of NLRP3 inflammasome via P2X7 in LPS-primed macrophages
Alarmin HNP-1 promotes pyroptosis and IL-1β release through different roles of NLRP3 inflammasome via P2X7 in LPS-primed macrophages
复制标题
Alarmin HNP-1 通过 P2X7 在 LPS 引发的巨噬细胞中通过 NLRP3 炎性体的不同作用促进细胞焦亡和 IL-1β 释放
DOI：
10.1177/1753425913490575
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发表时间：
2014-04-01
期刊：
影响因子：
3.2
通讯作者：
Fang, Xiangming
中科院分区：
文献类型：
--
作者：
Chen, Qixing;Jin, Yue;Fang, Xiangming
防御素是最早发现的具有报警功能的内源性介质，在免疫应答中起着多功能的作用。以前的研究报道，人中性粒细胞肽（HNP）-1，α-防御素亚家族的成员，可以调节IL-1 β的翻译后过程，但其潜在的机制尚不清楚。使用LPS引发的THP-1巨噬细胞模型，我们发现抑制P2 X嘌呤受体7（P2 X7）抑制HNP-1启动的成熟IL-1 β释放。共聚焦显微镜和谷胱甘肽S-转移酶（GST）pull-down实验证明HNP-1与P2 X7直接结合。HNP-1处理增加了caspase-1的活化水平，并且caspase-1的抑制消除了IL-1 β的释放。用氯化钾孵育LPS引发的巨噬细胞也阻止了HNP-1诱导的成熟IL-1 β的输出。同样地，溴化乙锭摄取测试显示由HNP-1触发的P2 X7-K+流出-半胱天冬酶-1信号传导途径有助于焦萎孔形成。此外，敲除炎性小体衔接子Nod样受体家族pyrin结构域3（NLRP 3）降低了活化的半胱天冬酶-1水平并减少了巨噬细胞中的孔形成，而IL-1 β释放没有显著受损。这些发现不仅阐明了Alarmin HNP-1增强炎症反应的机制，而且为防御素在某些炎症性疾病中发挥重要作用提供了治疗靶点。
Defensins are the first endogenous mediators to be characterized as alarmins and play multifunctional roles in immune response. Previous studies reported that human neutrophil peptide (HNP)-1, a member of the alpha-defensin subfamily, could regulate the IL-1 beta post-translational process; however, the underlying mechanism remained unknown. Using an LPS-primed THP-1 macrophage model, we found that inhibition of P2X purinoceptor 7 (P2X7) suppressed HNP-1-initiated mature IL-1 beta release. Confocal microscopy and glutathione S-transferase (GST) pull-down assay demonstrated that HNP-1 bound to P2X7 directly. HNP-1 treatment increased the activated level of caspase-1, and inhibition of caspase-1 abolished IL-1 beta release. Incubation of LPS-primed macrophages with potassium chloride also prevented HNP-1-induced export of mature IL-1 beta. Likewise, an ethidium bromide uptake test showed that the P2X7-K+ efflux-caspase-1 signaling pathway triggered by HNP-1 contributed to pyroptotic pore formation. Furthermore, knock down of inflammasome adaptor Nod-like receptor family pyrin domain containing 3 (NLRP3) decreased activated caspase-1 level and reduced pore formation in macrophages, whereas IL-1 beta release was not significantly impaired. These findings not only illustrated the mechanism for alarmin HNP-1 in enhancing inflammatory response, but also provided therapeutic targets for certain inflammatory diseases in which defensins play important roles.