CYCLOOXYGENASE AND PC12 CELLS

环氧合酶与PC 12细胞 在用NGF分化后，已经显示PC 12细胞 表达高水平的胰高血糖素。 前列腺素产生于 花生四烯酸通过环氧合酶（考克斯）的活性代谢 其以两种同种型存在。 通常发现考克斯-1是 组成型COX-2在多种细胞类型中表达，而考克斯-2在多种细胞类型中表达。 与其他直接早期基因的行为相似， 和瞬时诱导。 我们着手确定哪种考克斯亚型 在PC 12细胞中由NGF诱导，并开始了解 这种诱导机制。 我们发现NGF诱导考克斯-1蛋白在整个细胞质中表达， PCX细胞的神经突，亚克隆的PC 12系。 神经生长因子对考克斯-1有诱导作用 以剂量依赖性方式，在24- 48小时之间达到峰值水平， 保持升高长达10天。 这种诱导被抑制， 中和神经生长因子的抗体。 bFGF，而不是EGF， 考克斯-1蛋白的类似诱导，提示了 这种表型变化。 类似地，考克斯-1的mRNA水平在20 - 30岁之间达到峰值。 6和12小时，并保持高于基础水平至少48小时的反应 关于NGF 环己脲抑制这种信息增加。 考克斯-1活性 在第2天达到峰值，其诱导作用是未处理细胞的15倍， 吲哚美辛抑制了这种增加，其IC 50与 先前报道的考克斯-1值。 目前，我们的目的是确定NGF是否诱导PCX中的考克斯-1， 细胞是通过Ras激活或通过一些其他机制。 第二 感兴趣的领域是前列腺素类在PC 12中发挥的功能作用 NGF的分化。 关键词：COX-1，NSAIDs，PC 12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