Takayama H, Gimbrone M A, Schafer A I
Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115.
Biochim Biophys Acta. 1987 Dec 14;922(3):314-22. doi: 10.1016/0005-2760(87)90054-3.
We have examined the preferential incorporation of specific fatty acids into phospholipid classes of cultured human umbilical vein endothelial cells. Pulse-labeling of human umbilical vein endothelial cell phospholipids with radiolabeled fatty acids and inhibition of radiolabeled fatty acid incorporation by competition with excess, unlabeled fatty acids in pair-wise combinations revealed two distinct classes of esterification systems into human umbilical vein endothelial cell phospholipids. The eicosanoid precursor fatty acids, including arachidonate, 8,11,14-eicosatrienoate (ETA) and 5,8,11,14,17-eicosapentaenoate (EPA), exhibited high affinity incorporation into total phospholipids, whereas other fatty acids, including docosahexaenoate and monohydroxy eicosatetraenoates, showed low affinity incorporation. The relative degree of incorporation of eicosanoid precursor fatty acids into phospholipid classes was phosphatidylcholine (PC) greater than phosphatidylethanolamine (PE) greater than phosphatidylinositol (PI) greater than phosphatidylserine (PS). The specific activity of [14C]arachidonic acid-labeled PI was two times higher than that of any other radiolabeled phospholipids. When competitive incorporation of eicosanoid precursor fatty acids into phospholipid classes was studied, they were found to be acylated into different phospholipid classes at different rates. Although eicosanoid precursor fatty acids were not preferentially incorporated into PC, arachidonic acid was preferentially incorporated into the other phospholipids and exhibited particular selectivity in comparison with the other eicosanoid precursor fatty acids for incorporation into PI. These results demonstrate that human umbilical vein endothelial cells possess selective incorporation mechanisms for specific fatty acids into various phospholipids via the deacylation-reacylation pathway.
我们研究了特定脂肪酸在培养的人脐静脉内皮细胞磷脂类中的优先掺入情况。用人脐静脉内皮细胞磷脂与放射性标记脂肪酸进行脉冲标记，并通过与过量未标记脂肪酸以两两组合的方式竞争来抑制放射性标记脂肪酸的掺入，结果揭示了人脐静脉内皮细胞磷脂中有两类不同的酯化系统。类花生酸前体脂肪酸，包括花生四烯酸、8,11,14-二十碳三烯酸（ETA）和5,8,11,14,17-二十碳五烯酸（EPA），在总磷脂中表现出高亲和力掺入，而其他脂肪酸，包括二十二碳六烯酸和单羟基二十碳四烯酸，则表现出低亲和力掺入。类花生酸前体脂肪酸掺入磷脂类的相对程度为磷脂酰胆碱（PC）大于磷脂酰乙醇胺（PE）大于磷脂酰肌醇（PI）大于磷脂酰丝氨酸（PS）。[14C]花生四烯酸标记的PI的比活性比任何其他放射性标记的磷脂高两倍。当研究类花生酸前体脂肪酸竞争性掺入磷脂类时，发现它们以不同速率酰化到不同的磷脂类中。尽管类花生酸前体脂肪酸并非优先掺入PC，但花生四烯酸优先掺入其他磷脂，并且与其他类花生酸前体脂肪酸相比，在掺入PI方面表现出特殊的选择性。这些结果表明，人脐静脉内皮细胞通过去酰化-再酰化途径具有将特定脂肪酸选择性掺入各种磷脂的机制。
