title: Induction of prostacyclin/PGI2 synthase expression after cerebral ischemia-reperfusion.
abstract: Prostacyclin (PGI2), a potent vasodilator and inhibitor of platelet aggregation and leukocyte activation, is crucial in vascular diseases such as stroke. Prostacyclin synthase (PGIS) is the key enzyme for PGI2 synthesis. Although expression of PGIS was noted in the brain, its role in ischemic insult remains unclear. Here we reported the temporal and spatial expression of PGIS mRNA and protein after 60-min transient ischemia. Northern blot and in situ hybridization revealed a delayed increase of PGIS mRNA in the ischemic cortex at 24- to 72-h after ischemia; PGIS was detected mainly in the ipsilateral penumbra area, pyriform cortex, hippocampus, and leptomeninges. Western blot and immunohistochemical analysis revealed that PGIS proteins were expressed temporally and spatially similar to PGIS mRNA. PGIS was heavily colocalized with PECAM-1 to endothelial cells at the leptomeninges, large and small vessels, and localized to neuronal cells, largely at the penumbra area. A substantial amount of PGIS was also detected in the macrophage and glial cells. To evaluate its role against ischemic infarct, we overexpressed PGIS by adenoviral gene transfer. When infused 72 h before ischemia (- 72 h), Adv-PGIS reduced infarct volume by approximately 50%. However, it had no effect on infarct volume when infused immediately after ischemia (0 h). Eicosanoid analysis revealed selective elevation of PGI2 at - 72 h while PGI2 and TXB2 were both elevated at 0 h, altering the PGI2/thromboxane A2 (TXA2) ratio from 10 to 4. These findings indicate that PGIS protects the brain by enhancing PGI2 synthesis and creating a favorable PGI2/TXA2 ratio.
authors.affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, ROC.
authors.forename: Yao-Ching
authors.initials: YC
authors.lastname: Fang
authors.forename: Jui-Sheng
authors.initials: JS
authors.lastname: Wu
authors.forename: Jean-Ju
authors.initials: JJ
authors.lastname: Chen
authors.forename: Wai-Mui
authors.initials: WM
authors.lastname: Cheung
authors.forename: Ping-Hui
authors.initials: PH
authors.lastname: Tseng
authors.forename: Ka-Bik
authors.initials: KB
authors.lastname: Tam
authors.forename: Song-Kun
authors.initials: SK
authors.lastname: Shyue
authors.forename: Jin-Jer
authors.initials: JJ
authors.lastname: Chen
authors.forename: Teng-Nan
authors.initials: TN
authors.lastname: Lin
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000201:enzymology; D002545:Brain Ischemia / Q000201:enzymology*; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis / Q000235:genetics*; D011464:Epoprostenol / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D019746:Intramolecular Oxidoreductases / Q000032:analysis / Q000235:genetics*; D007700:Kinetics; D012333:RNA, Messenger; D051381:Rats; D015427:Reperfusion Injury / Q000201:enzymology*; D013928:Thromboxane A2 / Q000032:analysis; D014018:Tissue Distribution
chemical_list: D012333:RNA, Messenger; D013928:Thromboxane A2; D003577:Cytochrome P-450 Enzyme System; D011464:Epoprostenol; D019746:Intramolecular Oxidoreductases; C022461:prostacyclin synthetase