Paliogianni F, Boumpas D T
Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892-1268, USA.
Cell Immunol. 1996 Jul 10;171(1):95-101. doi: 10.1006/cimm.1996.0178.
Prostaglandin E2 (PGE2) release from activated macrophages and/or stimulation of T cells is associated with cAMP formation and activation of protein kinase A (PKA). cAMP inhibits Th1- but not Th2-cytokine production and may influence the nature of the immune response to a given antigen. Using DNA transfection and electrophoretic mobility shift assays (EMSA), we have examined the mechanisms for the transcriptional regulation of human IL-2 and IL-4 genes by PGE2. Stimulation of Jurkat cells with ionomycin and PMA in the presence of PGE2 inhibited the IL-2- but not the IL-4-promoter activity. In EMSAs, nuclear extracts from primary human T cells stimulated with ionomycin and phorbol esters in the presence of PGE2 demonstrated decreased binding at the AP-1 and NF-AT sites of the human IL-2 promoter; binding to the OCT-1 and NF-kappa B sites was not affected. These results suggest that cAMP regulates IL-2 production in human T cells by a transcriptional mechanism which involves discrete transactivating pathways for IL-2-promoter activation.
活化巨噬细胞释放前列腺素E2（PGE2）和/或T细胞受到刺激与环磷酸腺苷（cAMP）的形成以及蛋白激酶A（PKA）的激活相关。cAMP抑制Th1细胞因子的产生，但不抑制Th2细胞因子的产生，并且可能影响对特定抗原的免疫反应性质。我们使用DNA转染和电泳迁移率变动分析（EMSA），研究了PGE2对人白细胞介素-2（IL-2）和白细胞介素-4（IL-4）基因转录调控的机制。在PGE2存在的情况下，用离子霉素和佛波酯刺激Jurkat细胞，抑制了IL-2启动子活性，但未抑制IL-4启动子活性。在EMSA中，在PGE2存在的情况下，用离子霉素和佛波酯刺激的原代人T细胞核提取物显示，人IL-2启动子的活化蛋白-1（AP-1）和活化T细胞核因子（NF-AT）位点的结合减少；与八聚体转录因子-1（OCT-1）和核因子κB（NF-κB）位点的结合未受影响。这些结果表明，cAMP通过一种转录机制调节人T细胞中IL-2的产生，该机制涉及IL-2启动子激活的离散反式激活途径。
