Kurusu Shiro, Matsui Kohtaro, Watanabe Toshimichi, Tsunou Toshinobu, Kawaminami Mitsumori
Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan.
Cell Mol Neurobiol. 2008 Dec;28(8):1109-18. doi: 10.1007/s10571-008-9287-9. Epub 2008 Jun 5.
This study characterized the phospholipase A(2) (PLA(2)) activity in cerebral cortex of fetal rat brain and investigated effects of chemical inhibition of Ca(2+)-independent PLA(2) (iPLA(2)) on neurite outgrowth and cell development of cortical neurons in vitro. The PLA(2) activity in fetal brain was insensitive to a Ca(2+)-chelator EGTA and was significantly impaired by an iPLA(2) inhibitor, bromoenol lactone (BEL). Following treatment with BEL, cortical neurons showed acute loss of neurites and impaired cell body, which were clearly dose- and time-dependent. Nuclear staining revealed nuclear regression (shrinkage), but not fragmentation, in BEL-treated cells. The cytotoxic effect of BEL was additive with arachidonic acid (AA) and AA alone also induced neurite demise. BEL treatment resulted in increased production of prostaglandin E(2). Overall data suggest that iPLA(2), a primary PLA(2) isoform in cerebral cortex, displays a housekeeping role in development and neurite outgrowth in cortical neurons in vitro probably via maintaining phospholipid membrane remodeling rather than generating free fatty acids and lysophospholipids.
本研究对胎鼠大脑皮质中的磷脂酶A(2)（PLA(2)）活性进行了表征，并研究了化学抑制非钙依赖性磷脂酶A(2)（iPLA(2)）对体外培养的皮质神经元神经突生长和细胞发育的影响。胎脑内的PLA(2)活性对钙螯合剂乙二醇双四乙酸（EGTA）不敏感，但可被iPLA(2)抑制剂溴代依诺内酯（BEL）显著抑制。用BEL处理后，皮质神经元出现神经突急性丢失和细胞体受损，且具有明显的剂量和时间依赖性。细胞核染色显示，经BEL处理的细胞出现核皱缩（收缩），但无核碎裂。BEL的细胞毒性作用与花生四烯酸（AA）具有相加性，单独使用AA也可诱导神经突消亡。BEL处理导致前列腺素E(2)生成增加。总体数据表明，iPLA(2)作为大脑皮质中的主要PLA(2)亚型，可能通过维持磷脂膜重塑而非产生游离脂肪酸和溶血磷脂，在体外培养的皮质神经元发育和神经突生长中发挥看家作用。
