两型TNF-α对单核细胞系U937细胞功能的影响

Effect of the two types of TNF-α on the biological functions of monocytic cell line U937

目的 :比较两型TNF α对单核细胞系U937细胞功能的影响 ,以探讨跨膜型TNF α在炎症中的作用。方法 :通过吞噬、RT PCR、Westernblot及FACS等方法 ,比较两型TNF α对U937细胞生物学功能 (包括吞噬、细胞因子mRNA、胞质IκB α及ICAM 1表达等 )的影响。结果 :分泌型TNF α可明显促进U937细胞吞噬功能 ,使TNF α、IL 1β及IL 8mRNA积累增加 ,促进胞质IκB α降解及提高黏附分子ICAM 1的表达 ;而跨膜型TNF α对上述U937细胞的生物学功能则无明显影响。当二者联用时 ,跨膜型TNF α与分泌型TNF α亦无协同作用。结论 :分泌型TNF α对U937细胞具有明显地激活作用 ;而跨膜型TNF α则无影响 ,提示两型TNF α在炎症过程中的作用不同。

AIM: To compare the effect of the two types of TNF α, transmembrane TNF α (TM TNF α) and secreted TNF α (sTNF α) on the biological functions of monocytic cell line U937 so as to explore the role of TM TNF α in inflammation. METHODS: Effect of the two types of TNF α on the functions of U937 cells, such as phagocytosis, accumulation of cytokines’ mRNA, the level of cytoplasmic IκB α and expression of ICAM 1, was compared by phagocytosis, RT PCR, Western blot and FACS. RESULTS: sTNF α was found to be able to promote markedly phagocytosis by monocytic U937 cells, enhance the mRNA accumulation of cytokines, such as TNF α, IL 1β and IL 8 mRNA, induce the degradation of IκB α and the expression of adhesion molecular ICAM 1; while TM TNF α was shown to have no effect on the functions above of U937 cells. Furthermore, it seemed TM TNF α did not have a synergic action with sTNF α when U937 cells was treated with both types of TNF α. CONCLUSION: The data above shows that sTNF α can activate U937 cells, while TM TNF α has no influence. It suggests that the two types of TNF α may play the different role in inflammation.