炎症体
上睑下垂
粪肠球菌
分泌物
半胱氨酸蛋白酶1
促炎细胞因子
微生物学
细胞外
目标2
免疫印迹
THP1细胞系
白细胞介素8
生物
分子生物学
化学
细胞因子
受体
生物化学
免疫学
炎症
细胞培养
基因
大肠杆菌
遗传学
作者
Shujun Ran,Jing Huang,Bin Liu,Shensheng Gu,Wei Jiang,Liang Ji
标识
DOI:10.1016/j.micpath.2021.104761
摘要
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. 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. 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+. 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 P2X7R 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.
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