脂多糖预致敏的人骨髓间充质干细胞促炎机制研究

The immunoregulatory mechanisms of the pro-inflammatory phenotype of LPS-primed MSC

目的探索脂多糖(LPS)预致敏的人骨髓间充质干细胞(MSC)产生促炎功能的免疫调节机制。方法采用Real-time PCR和免疫荧光法检测MSC被预致敏前后TLR4信号通路相关分子(如TLR4、MyD88、TRAF6等)的表达水平,以及NF-κB的入核情况。通过Real-time PCR比较MSC被致敏前后促炎因子(IL-1β、IL-6、MIP-2、TNF-α)和Th1/Th2型细胞因子及其受体的表达差异。结果与未致敏的MSC相比,LPS预致敏的MSC中TLR4表达升高,NF-κB入核增加,促炎性因子IL-1β、IL-6、MIP-2、TNF-α表达升高,提示LPS预致敏可以激活MSC中的TLR4信号通路,并且诱导MSC中Th1型细胞因子及其受体表达升高,而Th2型细胞因子及其受体表达无变化或减少。结论MSC被LPS预致敏后TLR4信号通路激活,Th1型细胞因子及受体表达上调,从而诱导MSC分化成促炎表型。

Objective Our study aims to investigate the immunoregulatory mechanism of the pro-inflammatory phenotype of lipopolysaccharide（LPS）-primed MSC. Methods Real-time PCR was applied to examine the mRNA expression of TLR signaling molecules（e.g.,TLR4,MyD88,TRAF6）,and immunofluorescence staining microscopy was performed to detect the nuclear entry of NF-κB. The mRNA levels of pro-inflammatory cytokines including IL-1β,IL-6,MIP-2 and TNF-α,as well as Th1 / Th2 cytokines and their receptors in LPS-primed and unprimed MSC were determined by realtime PCR. Results LPS priming activated TLR4 signaling in MSC,as indicated by the enhanced expression of TLR4,MyD88 and TRAF6,as well as the increased nuclear entry of NF-κB.Moreover,mRNA levels of pro-inflammatory cytokines including IL-1β,IL-6,MIP-2 and TNF-α,as well as Th1 cytokines and their receptors were increased in LPSprimed MSC,while expression of Th2 cytokines and their receptors was either decreased or unchanged after LPS priming.Conclusion LPS priming in MSC activated TLR4 signaling and enhanced a Th1-versus Th2-type response,thereby leading to a pro-inflammatory phenotype.