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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。
Objective To investigate the effect of dt2 cAMP, PMA and IFNγ on the expression of C5aR in U937 cells and the change of cytoplasmic Ca2 + concentration in U937 cells stimulated by rhC5a with dt2 cAMP, PMA and IFN γ. Methods The expression of cytosolic C5aR and cytoplasmic protein tyrosine kinases was analyzed by flow cytometry. The change of cytosolic Ca2 + concentration was determined by fluorescence spectrophotometry. Results dt2 cAMP, PMA and IFN γ up-regulated C5aR expression to some extent. Upregulation of C5aR in U937 cells was induced by 0.5 mmol / L dt2 cAMP. Up-regulation of C5aR was not observed in 10-20 nmol / L PMA. IFN-γ also up-regulated C5aR expression on U937 cells. In addition, rhC5a stimulated the U937 cells differentiated by dt2 cAMP, PMA and IFNγ, and increased the cytosolic Ca2 + concentration. Genistein, a protein tyrosine kinase (PTK) inhibitor, significantly inhibited the increase of cytosolic Ca2 + in U937 cells induced by rhC5a. Conclusions PTK may be involved in the signal transduction during the C5a C5aR interaction.