屎肠球菌激活 NLRP3 炎性体，导致白细胞介素-1β分泌增加和 THP-1 巨噬细胞发生细胞焦亡。
Enterococcus Faecalis activates NLRP3 inflammasomes leading to increased interleukin-1 beta secretion and pyroptosis of THP-1 macrophages.
机构信息
Department of Endodontics and Operative Dentistry, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center of Stomatology, Shanghai, China.
Department of Endodontics and Operative Dentistry, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center of Stomatology, Shanghai, China.
出版信息
Microb Pathog. 2021 May;154:104761. doi: 10.1016/j.micpath.2021.104761. Epub 2021 Jan 29.
OBJECTIVES
Enterococcus faecalis is the bacterial species closely related to persistent infection in root canals. Interleukin-1 beta (IL-1β) is the most commonly detected proinflammatory cytokine in periapical granulation tissue and plays a critical role in host defenses against microbial infection. The synthesis and secretion of IL-1β are mediated mainly by Toll-like receptors and inflammasome activation. The previous study found that the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) and the absent in Melanoma 2 (AIM2) inflammasomes are positively expressed in periapical granulation tissue. The aim of this study was to investigate the pathogenicity of E. faecalis and the molecular mechanisms of IL-1β secretion by THP-1 macrophages infected with E. faecalis.
METHODS
The IL-1β and lactate dehydrogenase (LDH) levels induced by E. faecalis were investigated with enzyme-linked immunosorbent assay (ELISA) kit and cytotoxicity assay kit, caspase-1 and inflammasome expression levels were investigated using real time PCR and Western blot analysis. Then the effect of caspase-1, NLRP3, adenosine triphosphate (ATP), and extracellular K on IL-1β and LDH secretion, Gasdermin-D (GSDMD) cleavage induced by E. faecalis were analyzed.
RESULTS
E. faecalis significantly increased IL-1β and LDH release, caspase-1 and GSDMD cleavage, and NLRP3 inflammasome activation. It also showed that IL-1β and LDH release, GSDMD cleavage required caspase-1 and NLRP3 activation. Furthermore, the expression and activation of caspase-1 and NLRP3 were blocked by oxidized ATP and extracellular K.
CONCLUSION
E. faecalis infection activated caspase-1 and the NLRP3 inflammasome to induce IL-1β secretion and inflammatory cell death (pyroptosis). Furthermore, the activation and expression of NLRP3 induced by E. faecalis required P2XR and K efflux. This study furthers our understanding of the inflammatory response mechanism induced by E. faecalis indicates that NLRP3 may be a potential target for treatment and prevention of persistent periodontitis caused by E. faecalis.
目的
粪肠球菌是与根管内持续性感染关系最密切的细菌种类。白细胞介素-1β（IL-1β）是根尖肉芽组织中最常检测到的促炎细胞因子，在宿主抵御微生物感染的防御中起着关键作用。IL-1β的合成和分泌主要通过 Toll 样受体和炎性体激活来介导。先前的研究发现，核苷酸结合寡聚化结构域样受体蛋白 3（NLRP3）和黑素瘤缺失蛋白 2（AIM2）炎性体在根尖肉芽组织中呈阳性表达。本研究旨在探讨粪肠球菌的致病性及其诱导 THP-1 巨噬细胞分泌白细胞介素-1β的分子机制。
方法
通过酶联免疫吸附试验（ELISA）试剂盒和细胞毒性试验试剂盒检测粪肠球菌诱导的白细胞介素-1β和乳酸脱氢酶（LDH）水平，实时 PCR 和 Western blot 分析检测 caspase-1 和炎性体表达水平。然后分析 caspase-1、NLRP3、三磷酸腺苷（ATP）和细胞外 K 对粪肠球菌诱导的白细胞介素-1β和 LDH 分泌、Gasdermin-D（GSDMD）裂解的影响。
结果
粪肠球菌显著增加白细胞介素-1β和 LDH 的释放、caspase-1 和 GSDMD 的裂解以及 NLRP3 炎性体的激活。研究还表明，白细胞介素-1β和 LDH 的释放、GSDMD 裂解需要 caspase-1 和 NLRP3 的激活。此外，氧化的 ATP 和细胞外 K 可阻断 caspase-1 和 NLRP3 的表达和激活。
结论
粪肠球菌感染激活 caspase-1 和 NLRP3 炎性体诱导白细胞介素-1β分泌和炎症细胞死亡（细胞焦亡）。此外，粪肠球菌诱导的 NLRP3 的激活和表达需要 P2XR 和 K 外流。本研究加深了我们对粪肠球菌诱导的炎症反应机制的理解，表明 NLRP3 可能是治疗和预防粪肠球菌引起的持续性牙周炎的潜在靶点。
Zotero 插件