Abstract:

Objective Explore the role and status of tumor necrosis factor receptor-associated factor 6 (TRAF6) in the inflammatory response of human osteoblast-like cells MG63 which was triggered by Enterococcus faecalis (E. faecalis) and its lipoteichoic acid (LTA). Methods SiRNA technology was applied to silence the TRAF6 gene of MG63 cells, Using E.faecelis and its LTA to stimulate the silence MG63 cells with different hours. After that, using real-time PCR technology to detect toll-like receptor 2 (TLR2) and TRAF6 gene expression and using ELISA assay to detect proinflammatory cytokines interleukin-1β and TNF-alpha expression levels.Results When MG63 cells was infected by E. faecalis, its LTA, TLR2 and TRAF6 gene level has increased to varying degrees (P< 0.05); interleukin-1β and TNF-alpha expression was significantly higher (P< 0.05). When TRAF6 gene of MG63 cells was silenced by siRNA, pro-inflammatory cytokines interleukin-1β, interleukin-6, interleukin -8 and TNF-alpha expression decreased significantly (P< 0.05). Conclusion E. faecalis and its toxic components is identified by MG63 cells mainly through TLR2 receptors. The major virulence factor in periapical infections caused by E. faecalis is LTA.

Key words: E. faecalis, LTA, TLR2, Human osteoblast-like cells, TRAF6

摘要：

目的 探讨肿瘤坏死因子受体相关因子6（tumor necrosis factor receptor-associated factor 6,TRAF6）在粪肠球菌引发的人成骨样细胞MG63炎症反应中的作用。方法 采用siRNA瞬时干扰沉默MG63细胞的TRAF6基因,用粪肠球菌灭活全菌及其脂磷壁酸（lipoteichoic acid,LTA）刺激MG63细胞不同时间,定量PCR检测细胞中Toll样受体2（toll-like receptor 2,TLR2）和TRAF6的表达量;ELISA法检测MG63细胞产生的致炎因子白细胞介素1β（interleukin 1β,IL-1β）和肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）表达量。结果 粪肠球菌及其LTA感染MG63细胞,TLR2受体和TRAF6的基因水平都有不同程度的上升（P< 0.05）。IL-1β和TNF-α的表达量都显著增高（P< 0.05）。用siRNA抑制MG63细胞TRAF6表达后,促炎因子IL-1β和TNF-α的表达量显著下降（P< 0.05）。结论 MG63细胞主要通过TLR2受体来识别粪肠球菌及其毒性成分。粪肠球菌引起的根尖周感染中,其主要毒力因子是其细胞壁上的LTA。

关键词: 粪肠球菌, 脂磷壁酸, Toll样受体2, 人成骨样细胞, 肿瘤坏死因子受体相关因子6