title: Human group IIA secretory phospholipase A2 induces neuronal cell death via apoptosis.
abstract: Expression of group IIA secretory phospholipase A2 (sPLA2-IIA) is documented in the cerebral cortex (CTX) after ischemia, suggesting that sPLA2-IIA is associated with neurodegeneration. However, how sPLA2-IIA is involved in the neurodegeneration remains obscure. To clarify the pathologic role of sPLA2-IIA, we examined its neurotoxicity in rats that had the middle cerebral artery occluded and in primary cultures of cortical neurons. After occlusion, sPLA2 activity was increased in the CTX. An sPLA2 inhibitor, indoxam, significantly ameliorated not only the elevated activity of the sPLA2 but also the neurodegeneration in the CTX. The neuroprotective effect of indoxam was observed even when it was administered after occlusion. In primary cultures, sPLA2-IIA caused marked neuronal cell death. Morphologic and ultrastructural characteristics of neuronal cell death by sPLA2-IIA were apoptotic, as evidenced by condensed chromatin and fragmented DNA. Before apoptosis, sPLA2-IIA liberated arachidonic acid (AA) and generated prostaglandin D2 (PGD2), an AA metabolite, from neurons. Indoxam significantly suppressed not only AA release, but also PGD2 generation. Indoxam prevented neurons from sPLA2-IIA-induced neuronal cell death. The neuroprotective effect of indoxam was observed even when it was administered after sPLA2-IIA treatment. Furthermore, a cyclooxygenase-2 inhibitor significantly prevented neurons from sPLA2-IIA-induced PGD2 generation and neuronal cell death. In conclusion, sPLA2-IIA induces neuronal cell death via apoptosis, which might be associated with AA metabolites, especially PGD2. Furthermore, sPLA2 contributes to neurodegeneration in the ischemic brain, highlighting the therapeutic potential of sPLA2-IIA inhibitors for stroke.
authors.affiliation: Discovery Research Laboratories, Shionogi and Co., Ltd., Osaka, Japan. tatsurou.yagami@shionogi.co.jp
authors.forename: Tatsurou
authors.initials: T
authors.lastname: Yagami
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ueda
authors.forename: Kenji
authors.initials: K
authors.lastname: Asakura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hata
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kuroda
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sakaeda
authors.forename: Nobuo
authors.initials: N
authors.lastname: Takasu
authors.forename: Kazushige
authors.initials: K
authors.lastname: Tanaka
authors.forename: Takefumi
authors.initials: T
authors.lastname: Gemba
authors.forename: Yozo
authors.initials: Y
authors.lastname: Hori
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001095:Arachidonic Acids / Q000378:metabolism; D001921:Brain / Q000473:pathology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002544:Cerebral Infarction / Q000201:enzymology / Q000378:metabolism; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015777:Eicosanoids / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D054501:Group II Phospholipases A2; D006801:Humans; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000502:physiology*; D054467:Phospholipases A2; D015230:Prostaglandin D2 / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar
chemical_list: D001095:Arachidonic Acids; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D015777:Eicosanoids; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D010741:Phospholipases A; D054501:Group II Phospholipases A2; D054467:Phospholipases A2; D015230:Prostaglandin D2