弓形虫影响前列腺素E2合成的细胞内信号调节途径

目的　探讨弓形虫感染巨噬细胞过程中花生四烯酸 (AA)及前列腺素E₂ (PGE₂ )的产生及其相关的细胞内信号调节途径。　方法　构建刚地弓形虫 小鼠巨噬细胞侵染模型 ,应用气相色谱、酶联免疫吸附测定 (ELISA)、逆转录 聚合酶链反应 (RT-PCR)和蛋白质印迹法 (Westernblotting)检测钙离子调节剂乙二醇双 ( 2-氨基乙醚 )四乙酸 (EG-TA)、钙离子螯合剂 (BAPTA/AM )、钙调蛋白抑制剂三氟拉嗪 (TFP)及蛋白激酶C (PKC)抑制剂 1-( 5-磺酰基 ) 异喹啉-2-甲基-哌嗪盐酸盐 (H7)对弓形虫诱导的AA、PGE₂ 含量及促细胞分裂剂诱导性环加氧酶-2 (COX-2 )mRNA和蛋白质表达水平的影响。　结果　EGTA、BAPTA/AM及TFP均可抑制弓形虫诱导的巨噬细胞AA和PGE₂ 合成 ;PKC抑制剂H7可明显抑制弓形虫和脂多糖 (LPS)诱导的巨噬细胞PGE₂ 合成 ,并伴随着COX-2mRNA和蛋白质表达呈剂量依赖性减少。　结论　弓形虫侵染巨噬细胞过程可能通过钙信号转导途径调节COX-2底物AA的含量和PKC依赖的COX-2代谢途径调节PGE₂ 的合成。

Intra-cellular Signal Pathway and Synthesis of Prostaglandin E2 During Invasion of Macrophage by Toxoplasma gondii

Objective To investigate the signal transduction pathway of arachidonic acid(AA) and prostaglandin E-2(PGE-2) synthesis in macrophage invaded by Toxoplasma gondii. Methods Synthesis of AA and PGE-2, expression of COX_2 mRNA and protein following stimulation infection by Toxoplasma gondii were evaluated in RAW264^7 cells by ELISA, RT_PCR and Western blotting after treatment with calcium channel blocker verapamil, chelator of extracellular calcium EGTA and inhibitor of CaM trifluoperazine (TFP), selective PKC inhibitor H7. Results Production of AA and PGE-2 induced by tachyzoite was significantly inhibited by EGTA, TFP and BAPTA/AM, and the PGE-2 production was inhibited by H7, with a reduced expression of COX_2 mRNA and protein in a dose_dependent manner. Conclusion The parasite down_regulates macrophage functions by affecting PKC signaling pathways, and triggers a biochemical cascade whose signals ultimately conduct to the secretion of immunosuppressive molecules PGE-2.