Involvement of apoptosis in Periodontal diseases

目的：伴放线菌聚集杆菌感染诱导人单核细胞系THP-1凋亡。Toll样受体（TLR）是先天免疫系统的关键组分，识别病原体表面上的保守序列并触发宿主细胞功能。TLRs在A.放线菌共生体感染的细胞尚不清楚。本研究旨在探讨TLRs在A.方法：A。向悬浮在微管中的THP-1细胞中加入放线菌共生菌;随后，离心管（1000 × g，10分钟）。通过连续离心去除非粘附细菌。将感染的细胞转移到6孔培养板中，并在抗TLR 2或抗TLR 4抗体（10 μg/ ml）存在下孵育。RT-PCR检测TLR mRNA表达水平。采用APOPercentage（[○！R]）染料染色。结果：A组TLR 2 mRNA表达水平明显高于B组（P < 0. 05），A组TLR 2 mRNA表达水平明显高于B组（P < 0. 05）。放线菌共生体感染的细胞。TLR 4 mRNA水平无明显变化。感染后NFκB活性增加。结论：TLR 2在细胞凋亡信号通路中起重要作用，p38 MAPK和NF κ B均参与了细胞凋亡信号通路。感染的免疫细胞凋亡可能是牙周病进展的重要机制。

Objective: Aggregatibacter actinomycetemcomitans infection induces apoptosis in the human monocyte cell line THP-1. Toll-like receptors (TLRs), which are key components of the innate immune system, recognize conserved sequences on the surface of pathogens and trigger host cell function. However, roles of TLRs in the induction of apoptosis in A. actinomycetemcomitans-infected cells is unclear. The objective of this study was to examine the roles of TLRs in apoptosis of A. actinomycetemcornitans-infected THP-1 cells.Methods : A. actinomycetemcomitans was added to THP-1 cells suspended in microtubes ; subsequently, the tubes were centrifuged (1000 x g, 10 min). Non-adherent bacteria were removed via serial centrifugation. Infected cells were transferred to 6-well culture plates and incubated in the presence of either anti- TLR2 or -TLR4 antibody (10 μg/ ml). TLR mRNA level was confirmed by RT-PCR. Apoptotic cells were detected by APOPercentage ([○!R]) dye staining. Cellular p38 activity and NFκB activity were assessed with ELISA kitsResults: A significant increased in TLR2 mRNA level was observed in A. actinomycetemcomitans-infected cells. However, no meaningful change was detected in TLR4 mRNA level. NFκB activity increased following infection. Moreover, percentages of apoptotic cells as well as p38 MAPK and NFκB activities in infected cells decreased upon addition of anti-TLR2 antibody.Conclusion : These findings indicate that TLR2 play a key role in the apoptotic signal pathway and that both p38 MAPK and NFκB are involved in the pathway. Apoptosis of infected human immune cells may be an important mechanism in the progression of periodontal disease.