Differential Utilization of the Ethanolamine Moiety of Phosphatidylethanolamine Derived from Serine and Ethanolamine during NGF-Induced Neuritogenesis of PC12 Cells
Differential Utilization of the Ethanolamine Moiety of Phosphatidylethanolamine Derived from Serine and Ethanolamine during NGF-Induced Neuritogenesis of PC12 Cells
复制标题
DOI：
10.1023/a:1007540023885
复制
发表时间：
2000-02
影响因子：
4.4
通讯作者：
A. Ikemoto;H. Okuyama
中科院分区：
文献类型：
--
作者：
A. Ikemoto;H. Okuyama
神经突延伸涉及质膜的扩张和磷脂的合成。我们研究了神经生长因子（NGF）诱导的PC 12细胞突起生长过程中膜磷脂酰乙醇胺（PE）的生物合成。用[~ 3 H]乙醇胺预标记PE，再用1 mM未标记乙醇胺孵育，[~ 3 H]PE的放射性逐渐下降，[~ 3 H]乙醇胺在神经突生长过程中释放到NGF处理的细胞培养基中;在不存在未标记的乙醇胺的情况下，[3 H]PE的放射性在至少24小时内保持相对恒定。在未分化的细胞中，而不是在NGF处理的细胞中，[3 H]磷酸乙醇胺在脉冲标记期间大量积累，并部分转化为PE，但大部分释放到培养基中，而与未标记的乙醇胺孵育无关。在未分化细胞中也观察到与未标记乙醇胺孵育后[3 H]PE放射性下降和[3 H]乙醇胺释放。因此，衍生自乙醇胺的PE的乙醇胺部分在分化的和未分化的细胞中被积极地再循环。当PE是通过磷脂酰丝氨酸（PS）脱羧衍生自[3 H]丝氨酸时，仅在经NGF处理的细胞中观察到[3 H]PE的放射性降低和与未标记乙醇胺孵育后[3 H]乙醇胺释放到培养基中，但未分化细胞中未观察到，表明衍生自PS的PE的乙醇胺部分仅在经历NGF诱导的轴突发生的细胞中积极再循环。因此，在PC 12细胞中，来自PS的PE的乙醇胺部分与来自乙醇胺的PE的乙醇胺部分受到不同的调节。
Neurite elongation involves the expansion of the plasma membrane and phospholipid synthesis. We investigated membrane phosphatidylethanolamine (PE) biosynthesis in PC12 cells during neurite outgrowth induced by nerve growth factor (NGF). When PE was prelabeled with [3H]ethanolamine and the radioactivity was chased by incubation with 1 mM unlabeled ethanolamine, the radioactivity of [3H]PE steadily declined and [3H]ethanolamine was released into the medium in NGF-treated cells during neurite outgrowth; in the absence of unlabeled ethanolamine, the radioactivity of [3H]PE remained relatively constant for at least 24 hr. In undifferentiated cells but not in NGF-treated cells, [3H]phosphoethanolamine accumulated in significant amounts during pulse labeling, and was converted partly to PE but largely released into the medium irrespective of incubation with unlabeled ethanolamine. The decline in the radioactivity of [3H]PE and release of [3H]ethanolamine following incubation with unlabeled ethanolamine were also observed in undifferentiated cells. Thus, the ethanolamine moiety of PE derived from ethanolamine is actively recycled in both differentiated and undifferentiated cells. When PE was derived from [3H]serine through phosphatidylserine (PS) decarboxylation, the decrease in radioactivity of [3H]PE and release of [3H]ethanolamine into the medium following incubation with unlabeled ethanolamine were observed only in NGF-treated cells, but not in undifferentiated cells, indicating that the ethanolamine moiety of PE derived from PS is actively recycled only in the cells undergoing NGF-induced neuritogenesis. Thus, in PC12 cells, the ethanolamine moiety of PE derived from PS is regulated differently from that of PE derived from ethanolamine.