前列环素类似物对调节性T细胞分化的调节作用及机制  

The regulatory effects of a epoprostenol analog on the differentiation of CD4＋ T cells to Treg cells and the possible mechanism

作　　者：刘文宣[1] 贾娴娴[2] 李慧[2] 刘文聪[3] 杨磊[1] 李涛[1] 胡洁[2] 

机构地区：[1]河北医科大学公共卫生学院,石家庄050017 [2]河北医科大学基础医学院,石家庄050017 [3]河北医科大学第一附属医院,石家庄050011

出　　处：《中华微生物学和免疫学杂志》2016年第1期27-33,共7页Chinese Journal of Microbiology and Immunology

基　　金：基金项目：河北省高等学校科学技术研究项目（QN2015006）;河北省医学科学研究重点课题计划指导项目（20150626）

摘　　要：目的探讨前列环素（PGI2）类似物伊洛前列素（Iloprost）对调节性T细胞（regulatory T cells，Treg）分化的调节作用及其信号机制。 方法采用免疫磁珠分选人外周血初始CD4＋ T细胞，体外诱导其向Treg细胞分化，使用流式细胞术、RT-PCR方法分别从Treg细胞频率和Foxp3 mRNA表达2个方面探讨Iloprost对Treg细胞分化的调节作用及其受体机制。之后，使用免疫荧光法测定胞内cAMP含量，流式细胞术检测胞内STAT5磷酸化水平，以探索Iloprost调节Treg细胞分化的信号通路。 结果Iloprost剂量依赖性地降低了Treg细胞频率和Foxp3 mRNA表达（P〈0.05），而IP受体被受体阻断剂（CAY10449）阻断之后，Iloprost的上述抑制作用大幅回升。Iloprost可上调Treg细胞胞内cAMP水平（P〈0.05），其对Treg细胞分化的调节作用能被cAMP激动剂db-cAMP模拟（P〉0.05），且被蛋白激酶A（PKA）抑制剂H-89所逆转。另外，Iloprost可下调IL-2诱导的STAT5磷酸化（P〈0.05）。同时，db-cAMP模拟了Iloprost对pSTAT5的调节作用（P〉0.05），而该作用被H-89抑制。 结论Iloprost通过与IP受体结合，活化cAMP-PKA信号通路，从而下调pSTAT5水平，进而抑制CD4＋ T细胞向Treg分化。ObjectiveTo investigate the roles of a epoprostenol（PGI2） analog （Iloprost） in regulating the differentiation of CD4＋ T cells to Treg cells and the possible mechanism. MethodsNa？ve CD4＋ T cells were isolated from human peripheral blood samples by using the magnetic-activated cell sorting （MACS） and then cultured under Treg-polarizing condition. The percentages of Treg cells and the expression of Foxp3 at mRNA level were respectively measured by using flow cytometry and RT-PCR for evaluation the effects of Iloprost on the differentiation of CD4＋ T cells to Treg cells. The cAMP accumulation assay was used to detect the level of intracellular cAMP. Flow cytometry analysis was performed to detect the phosphorylation of signal transducer and activator of transcription 5 （STAT5）. ResultsIloprost decreased the percentage of Treg cells and inhibited the expression of Foxp3 at mRNA level in a dose dependent manner （P〈0.05）. However, the inhibitory effects of Iloprost were weakened when IP receptors were blocked by IP antagonist （CAY10449）. A six-fold increase in the levels of intracellular cAMP in Treg cells was induced by Iloprost （P〈0.05） and a similar effect could be achieved by using a cAMP agonist, db-cAMP （P〉0.05）. H-89, a protein kinase A inhibitor, inhibited the Iloprost-induced expression of cAMP in Treg cells. Moreover, Iloprost inhibited the IL-2 mediated phosphorylation of STAT5 （P〈0.05） and a similar effect could be achieved by using db-cAMP （P〉0.05）. The Iloprost-mediated down-regulation of pSTAT5 was blocked by using H-89. ConclusionPGI2 could activate the cAMP-PKA signaling pathway by binding to the IP receptor, resulting in inhibited phosphorylation of STAT5 and suppressed differentiation of na？ve CD4＋ T cells to Treg cells.

关 键 词：PGI2 类似物 调节性T细胞 分化 信号通路 

分 类 号：R392[医药卫生—免疫学]