CYCLOOXYGENASE AND PC12 CELLS

环氧合酶与PC12细胞 经NGF诱导分化后，PC-12细胞被显示为 表现出前列腺素水平升高。前列腺素产生于 环氧合酶(COX)活性对花生四烯酸代谢的影响 它以两种亚型存在。COX-1通常被发现是 在多种细胞类型中结构性表达，而COX-2 与其他直接早期基因的行为相似，因为它是快速的 并在瞬间被诱导。我们开始确定COX的哪一种亚型 在PC12细胞中被NGF诱导，并开始了解 这种诱导的机制。 我们发现，NGF诱导COX-1蛋白遍及细胞质，并 PCX细胞突起，亚克隆的PC12细胞系。神经生长因子诱导的环氧合酶-1 以剂量依赖的方式，在24-48小时和 在长达10d的时间内保持高位。这种诱导作用被抑制了 NGF中和抗体。此外，碱性成纤维细胞生长因子而不是表皮生长因子引起了 COX-1蛋白的类似诱导，提示了一种潜在的机制 这种表型变化。同样，COX-1的mRNA水平在 6小时和12小时，并在反应中保持高于基础水平至少48小时 致NGF。环己胺可抑制这一信息的增加。环氧合酶-1活性 在2天内达到顶峰，比未处理的细胞诱导15倍 这种增加被吲哚美辛抑制，其IC50与 此前报道的COX-1的值。 目前，我们的目标是确定NGF对PCX中COX-1的诱导 细胞是通过RAS激活或通过某种其他机制。一秒钟 感兴趣的领域是前列腺素在PC12中扮演的功能角色 神经生长因子诱导分化。 关键词：COX-I，NSAIDs，PC12细胞，RAS，感觉神经元

Cyclooxygenase and PC12 Cells Following differentiation with NGF, PC 12 cells have been shown to express elevated levels of prostaglandins. Prostaglandins arise from arachadonic acid metabolism through the activity of cyclooxygenase (COX) which exists as two isoforms. COX-1 is typically found to be constituitively expressed in a variety of cell types, whereas COX-2 behaves similarly to other immediate early genes in that it is rapidly and transiently induced. We set out to determine which isoform of COX is induced by NGF in PC 12 cells and to begin to understand the mechanism of this induction. We found that NGF induces COX-1 protein throughout the cytoplasm and neurites of PCX cells, a subcloned PC12 line. COX-1 was induced by NGF in a dose-dependent fashion, reaching peak levels between 24-48h and remaining elevated for as long as 1Od. This induction was inhibited by neutralizing antibodies to NGF. Moreover, bFGF but not EGF caused a similar Induction of COX-1 protein, suggesting a potential mechanism for this phenotypic change. Similarly, mRNA levels for COX-1 peaked between 6 and 12h and remained above basal levels for at least 48h in response to NGF. Cyclohexamide inhibited this message increase. COX-1 activity peaked at 2 days with a 15-fold induction over non-treated cells and this increase was inhibited by indomethicin with an IC50 similar to previously reported values for COX-1. Currently, our aim is to determine whether NGF induction of COX-1 in PCX cells is via Ras activation or through some other mechanism. A second area of interest is the functional role that prostanoids play in PC12 differentiation by NGF. Keywords: COX-I, NSAIDs, PC12 cells, Ras, sensory neurons