神经节苷脂GM_3对人白血病J6－2细胞磷脂酰胆碱代谢的影响

The Effect of Ganglioside GM_3 on the Metabolism of Phosphatidylcholine in Human Monocytoid Leukemia J6-2 Cells

神经节苷脂ＧＭ３诱导人单核样白血病Ｊ６－２细胞沿单核／巨噬细胞途径分化．在ＧＭ３诱导分化同时，Ｊ６－２细胞磷脂代谢发生了显著变化．采用（（３２）Ｐ）Ｐｉ、［ＧＨ３－３Ｈ］胆碱和［ＣＨ３－３Ｈ］ＳＡＭ参入实验对ＧＭ３影响Ｊ６－２细胞ＰＣ代谢的机制进行了初步的探讨．ＧＭ３促进［（３２）Ｐ］Ｐｉ参入Ｊ６－２细胞ＰＣ；抑制［ＣＨ３－３Ｈ］胆碱参入ＰＣ及ＰＣ合成的前体磷酸胆碱及ＣＤＰ－胆碱；ＧＭ３促进［ＣＨ３－３Ｈ］ＳＡＭ参入ＰＣ，但抑制［ＣＨ３－３Ｈ］ＳＡＭ参入ＰＣ合成的前体胆碱、磷酸胆碱和ＣＤＰ－胆碱．上述结果提示，ＧＭ３抑制Ｊ６－２细胞ＰＣ合成的ＣＤＰ－胆碱途径，促进ＰＣ合成的ＰＥ甲基化途径．

Ganglioside GM_3,a physiological cell differentiation inducer, can markedly influence the phospholipid metabolism in human leukemia J6-2 cells. In the present paper,the effect of short term treatment with GM_3 on the metabolism of PC in J6-2 cells had been studied by the incorporation of [32￣P]Pi, [CH_3-3￣H]choline and [CH_3-￣3H] SAM. The results show that GM_3 enhanced the incorporation of [32￣P]Pi into PC,inhibited the incorporation of [CH_3-￣3H]choline into PC, phosphorylcholine and CDP-choline. GM_3 stimulated the incorporation of [￣3H]CH_3-in [CH_3￣3H] SAM into PC,but inhibited the incorporation of [￣3H]CH_3-in [CH_3-￣3H]SAM into choline,phosphorylcholine,and CDP-choline. The results suggest that GM_3 inhibits the PC biosynthesisvia the CDP-choline pathway,stimulates the PC biosynthesis by the methylation of PE.