TM-TNF-α介导的反向信号协同增强sTNF-α对U937细胞的激活作用

Reverse signaling by TM-TNF-α augments the activation of U937 induced by sTNF-α

目的 用sTNFRⅠ预先激活TM TNF α介导的反向信号 ,观测其对sTNF α激活单核细胞系U937细胞的影响。方法 预先用sTNFRⅠ与U937细胞作用 30min ,洗涤后加入sTNF α作用不同时间 ,观测预激活反向信号对sTNF α刺激U937产生活性氧、胞内促炎细胞因子TNF α、IL 1 β、IL 8mRNA的转录及IκB α水平 (Westernblot)的影响。结果 单独用sTNFRⅠ激活的反向信号并不影响U937细胞的功能 ,而预激活反向信号能协同增强sTNF α刺激U937细胞产生活性氧 ,且呈sTNFRⅠ浓度、sTNF α浓度依赖关系 ;预激活反向信号协同增强sTNF α刺激U937炎性细胞因子mRNA(TNF α、IL 1 β、IL 8等 )的转录水平 ;并促进U937细胞IκB α的降解。结论 预先激活TM TNF α介导的反向信号协同增强sTNF α对U937的激活作用 ,提示反向信号可能参与机体对早期炎症反应的调节。

Objective To investigate the effect of reverse signaling by transmembrane TNF-α (TM-TNF-α) on the activation of U937 induced by sTNF. Methods U937 cells were pre-incubated with sTNFRⅠ for 30 min and then stimulated with sTNF-α for different time. The biological activities of U937 cells, including the production of active oxygen, the transcription of intracellular pro-inflammatory cytokines, such as TNF-α, IL-1β, IL-8 mRNA, and expression of cytoplasmic IκB-α were measured. Results sTNFRⅠ alone did not influence the biological activities of U937 cells. Reverse signaling through TM-TNF induced by sTNFRⅠ promoted sTNF-stimulated U937 produce more active oxygen, which is dose-dependant of sTNFRⅠ and sTNF-α. Reverse signaling also enhanced mRNA transcription of cytokines such as TNF-α, IL-1β and IL-8 and accelerated the degradation of IκB-α. Conclusion Reverse signaling by TM-TNF-α induced by sTNFRⅠ augment with activation of U937 stimulated with sTNF, suggesting that reverse signaling may be involved in the regulation of early inflammation.