dt_2-cAMP,IFN-γ和PMA对U937胞浆Ca^(2+)和酪氨酸激酶的影响

Effects of dt_2-cAMP,IFN-γand PMA on cytosolici[Ca^(2)]i and protein tyrosine kinase-in U937 cells

目的探讨dt2 cAMP ,PMA和IFN γ对U937细胞C5aR表达的影响 ,以及rhC5a刺激受dt2 cAMP ,PMA和IFN γ分化的U937细胞后 ,其胞浆Ca2 +浓度的变化情况。方法用流式细胞仪分析胞膜C5aR和胞浆蛋白酪氨酸激酶的表达 ;荧光发光法测定胞浆Ca2 +浓度的变化。结果dt2 cAMP ,PMA和IFN γ等可不同程度地上调C5aR表达。用0.5mmol/L的dt2 cAMP就足以上调U937细胞C5aR分子 ,10～20nmol/L浓度范围的PMA对C5aR表达的上调没有明显差异 ,IFN γ也可上调U937细胞上C5aR的表达。此外 ,rhC5a刺激受dt2 cAMP ,PMA和IFN γ分化的U937细胞 ,可使其细胞浆Ca2 +浓度上升。蛋白酪氨酸激酶(PTK)抑制剂Genistein可明显抑制rhC5a所致U937细胞胞浆Ca2 +浓度升高。结论PTK可能参与了C5a C5aR相互作用过程中的信号转导。

Aim To investigate the effects of dt2 cAMP (a combination material of vitamin D3 metabolite 1,25(OH)2D3 with the cAMP agonist protaglandin,isoproterol and forskolin),IFN γand PMA on the expression of C5a receptor(CD88) ofthe U937 cells. To study the cytoplasmic calcium concentration in U937,which was differentiated by dt2 cAPM,IFN γand PMA, induced by rhC5a. Methods The C5aR expression and the level of protein tyrosine kinase(PTK) in U937 were determined by using flow cytometer. Cytosolici concentration was determined by using fluorescence spectrophometer. Results The C5aR expression could be upregulated by 0.5mmol/L dt2 cAMP. When U937 cells were differentiated by dt2 cAMP, IFN γand PMA respectively,they were stimulated by rhC5a.In addition, their cytoplasmic calcium concentration increased because rhC5a upregulated the level of the PTK in U937 cells. Genistein, an inhibitor of PTK, could inhibit the increase of cytosolic i concentration in U937 cells that were induced by rhC5a. Conclusion These results indicated that PTK might take part in the signal transduction of the interaction between C5a and C5aR in U937 cells.