人牙龈上皮细胞诱导分泌β-防御素的信号通路研究

Signaling pathways involved in the induced β-defensins in human gingival epithelial cells

目的研究牙龈上皮细胞在炎症因子IL-1β,TNF-α诱导下分泌β-防御素1,2,3的信号通路。方法取30岁以下因拔除第三磨牙或助萌需切除的牙龈,原代培养人牙龈上皮细胞,并用10μmol/L MAPK抑制剂SB203580或NF-κB抑制剂BAY 11-7082孵育2 h,而后用150 ng/ml IL-1β或TNF-α诱导抑制剂孵育过的细胞24 h,实时荧光定量PCR检测β-防御素1,2,3的基因表达水平。结果在MAPK或NF-κB抑制剂存在的情况下,人牙龈上皮细胞经炎症因子IL-1β,TNF-α诱导后,HBD-1的表达量无明显变化;但HBD-2的表达量明显降低,MAPK抑制剂使牙龈上皮细胞在IL-1β和TNF-α诱导下分泌HBD-2的量分别下降81%和76%,NF-κB抑制剂使牙龈上皮细胞在IL-1β和TNF-α诱导下分泌HBD-2的量分别下降93%和95%;两种抑制剂对HBD-3的表达量表现出不同效应,MAPK抑制剂使牙龈上皮细胞在IL-1β和TNF-α诱导下分泌HBD-3的量分别下降65%和66%,而NF-κB抑制剂对HBD-3的表达量无明显影响。结论人牙龈上皮细胞较稳定的分泌HBD-1,不受外界炎症因子及信号通路抑制剂的影响。MAPK和NF-κB信号通路在HBD-2的诱导分泌中起了非常重要的作用;本研究中MAPK信号通路与HBD-3的诱导表达密切相关。

Objective The purpose of this study is to investigate the signaling pathways involved in humanβ-defensins (HBD-1,2,3) induction in response to IL-1βand TNF-αin human gingival epithelial cells. Methods Healthy gingival samples were obtained from patients less than 30 years old undergoing the third-molar extraction or impacted teeth exposure. Primary human epithelial cells were cultured, then the cells were pretreated with 10μmol/L MAPK or NF-κB inhibitor for 2 hours and cultured further with 150 ng/ml IL-1β or TNF-α. Quantitative real-time PCR was utilized to quantify the HBD-1,2,3 mRNA expression. Results HBD-1 induction by IL-1βwas not blocked in the presence of MAPK or NF-κB inhibitor. The HBD-1 induction by TNF-αwas similar to that of IL-1β. In contrast, there was a notable decrease in HBD-2 induction by IL-1βand the reduction was 81%by MAPK inhibitor and 93%by NF-κB inhibitor. Similarly, the HBD-2 induction by TNF-α was inhibited by 76% by MAPK inhibitor and 95% by NF-κB inhibitor. HBD-3 induction was different from HBD-2. The HBD-3 expression level induced by IL-1βwas decreased by 65%in the presence of MAPK inhibitor and induced expression by TNF-α was decreased 66%. Whereas the NF-κB inhibitor showed no inhibition on HBD-3 induction both by IL-1β and TNF-α. Conclusion Our results suggested that different signaling pathways were involved in the induction of humanβ-defensins in human gingival epithelial cells stimulated by IL-1βand TNF-α. For induced HBD-1 expression by IL-1βand TNF-α, neither MAPK nor NF-κB was essential or sufficient. Both MAPK and NF-κB signaling pathways played an important role in the HBD-2 induction by IL-1βand TNF-α. Whereas the NF-κB inhibitor showed no inhibition on HBD-3 induction both by IL-1βand TNF-α.