Xu F Y, Kardami E, Nemer M, Choy P C, Hatch G M
Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, R3E OW3, Canada.
Exp Cell Res. 2000 May 1;256(2):358-64. doi: 10.1006/excr.2000.4849.
The biosynthesis of phosphatidylethanolamine was examined during differentiation of P19 teratocarcinoma cells into cardiac myocytes. P19 cells were induced to undergo differentiation into cardiac myocytes by the addition of dimethyl sulfoxide to the medium. Immunofluorescence labeling confirmed the expression of striated myosin 10 days postinduction of differentiation. The content of phosphatidylethanolamine increased significantly within the first 2 days of differentiation. [1,3-(3)H]Glycerol incorporation into phosphatidylethanolamine was increased 7.2-fold during differentiation, indicating an elevation in de novo synthesis from 1, 2-diacyl-sn-glycerol. The mechanism for the increase in phosphatidylethanolamine levels during cardiac cell differentiation was a 2.8-fold increase in the activity of ethanolaminephosphotransferase, the 1,2-diacyl-sn-glycerol utilizing reaction of the cytidine 5'-diphosphate-ethanolamine pathway of phosphatidylethanolamine biosynthesis. Incubation of P19 cells with the phosphatidylethanolamine biosynthesis inhibitor 8-(4-chlorophenylthio)-cAMP inhibited the differentiation-induced elevation in phosphatidylethanolamine levels but did not affect the expression of striated myosin. The results suggest that elevation in phosphatidylethanolamine is an early event of P19 cell differentiation into cardiac myocytes, but is not essential for differentiation to proceed.
在P19畸胎瘤细胞分化为心肌细胞的过程中，对磷脂酰乙醇胺的生物合成进行了研究。通过向培养基中添加二甲基亚砜，诱导P19细胞分化为心肌细胞。免疫荧光标记证实了分化诱导后10天横纹肌肌球蛋白的表达。在分化的头2天内，磷脂酰乙醇胺的含量显著增加。在分化过程中，[1,3-(3)H]甘油掺入磷脂酰乙醇胺的量增加了7.2倍，表明从1,2-二酰基-sn-甘油的从头合成有所增加。心脏细胞分化过程中磷脂酰乙醇胺水平升高的机制是乙醇胺磷酸转移酶的活性增加了2.8倍，乙醇胺磷酸转移酶参与磷脂酰乙醇胺生物合成的胞苷5'-二磷酸-乙醇胺途径中利用1,2-二酰基-sn-甘油的反应。用磷脂酰乙醇胺生物合成抑制剂8-(4-氯苯硫基)-cAMP孵育P19细胞，可抑制分化诱导的磷脂酰乙醇胺水平升高，但不影响横纹肌肌球蛋白的表达。结果表明，磷脂酰乙醇胺水平升高是P19细胞分化为心肌细胞的早期事件，但对于分化的进行并非必不可少。
