[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 E2 (PGE2) synthesis in macrophage invaded by Toxoplasma gondii.


METHODS
Synthesis of AA and PGE2, 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 PGE2 induced by tachyzoite was significantly inhibited by EGTA, TFP and BAPTA/AM, and the PGE2 production was inhibited by H7, with a reduced expression of COX-2 mRNA and protein in a dose-dependent manner.


CONCLUSIONS
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 PGE2.
Research Center of Molecular Medicine, Fujian Medical University, Fuzhou 350004, China.
Bi-wen
BW
Peng
Da-li
DL
Zheng
Xue-mei
XM
Jiang
Jian-yin
JY
Lin
Ming-sen
MS
Jiang
D000818:Animals; D016718:Arachidonic Acid / Q000096:biosynthesis; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis*; D015536:Down-Regulation; D008264:Macrophages / Q000378:metabolism / Q000469:parasitology*; D051379:Mice; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology*; D014122:Toxoplasma / Q000502:physiology*
D012333:RNA, Messenger; D016718:Arachidonic Acid; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D011493:Protein Kinase C; D015232:Dinoprostone