Campbell F M, Clohessy A M, Gordon M J, Page K R, Dutta-Roy A K
Rowett Research Institute, Aberdeen, Scotland, United Kingdom.
J Lipid Res. 1997 Dec;38(12):2558-68.
In order to understand the mechanisms by which fatty acids are taken up by the placenta, the uptake of oleic, linoleic, arachidonic, and docosahexaenoic acids by cultured human placental choriocarcinoma (BeWo) cells was examined. Fatty acid uptake by BeWo cells was temperature-dependent and exhibited saturable kinetics. Oleic acid was taken up least and docosahexaenoic acid most by these cells. Moreover, competitive studies of fatty acid uptake by BeWo cells also indicated preferential uptake compared with oleic acid in the order of docosahexaenoic acid, arachidonic acid, and linoleic acid. Western blot analysis demonstrated that BeWo cells express a protein immunoreactive with antibodies to the human placental plasma membrane fatty acid-binding protein (p-FABPpm). Furthermore, pre-treatment of BeWo cells with these antibodies inhibited most of the uptake of docosahexaenoic (64%) and arachidonic acids (68%) whereas oleic acid uptake was inhibited only 32% compared with the controls treated with preimmune serum. These results clearly demonstrate that the pFABPpm may be involved in the preferential uptake of essential fatty acids (EFA) and their long chain polyunsaturated fatty acids (LCPUFA) by these cells. Studies on the distribution of radiolabeled fatty acids in the cellular lipids of BeWo cells showed that docosahexaenoic acid was incorporated mainly in the triacylglycerol fraction, followed by the phospholipid fraction, whereas for arachidonic acid the reverse was true. The preferential incorporation of docosahexaenoic acid into triacylglycerol suggests that triacylglycerol may play an important role in the placental transport of docosahexaenoic acid to the fetal circulation. Together these results demonstrate the preferential uptake of EFA/LCPUFA by BeWo cells that is most probably mediated via the pFABPpm. We thus propose that the p-FABPpm may be involved in the sequestration of maternal plasma LCPUFA by the placenta.
为了了解脂肪酸被胎盘摄取的机制，研究了培养的人胎盘绒毛膜癌细胞（BeWo细胞）对油酸、亚油酸、花生四烯酸和二十二碳六烯酸的摄取情况。BeWo细胞对脂肪酸的摄取具有温度依赖性，并呈现出饱和动力学。这些细胞摄取油酸最少，摄取二十二碳六烯酸最多。此外，对BeWo细胞脂肪酸摄取的竞争性研究还表明，与油酸相比，二十二碳六烯酸、花生四烯酸和亚油酸依次优先摄取。蛋白质印迹分析表明，BeWo细胞表达一种与抗人胎盘质膜脂肪酸结合蛋白（p-FABPpm）抗体发生免疫反应的蛋白质。此外，用这些抗体预处理BeWo细胞可抑制大部分二十二碳六烯酸（64%）和花生四烯酸（68%）的摄取，而与用免疫前血清处理的对照相比，油酸摄取仅被抑制32%。这些结果清楚地表明，pFABPpm可能参与了这些细胞对必需脂肪酸（EFA）及其长链多不饱和脂肪酸（LCPUFA）的优先摄取。对BeWo细胞的细胞脂质中放射性标记脂肪酸分布的研究表明，二十二碳六烯酸主要掺入三酰甘油部分，其次是磷脂部分，而花生四烯酸的情况则相反。二十二碳六烯酸优先掺入三酰甘油表明，三酰甘油可能在胎盘将二十二碳六烯酸转运到胎儿循环中起重要作用。这些结果共同证明了BeWo细胞对EFA/LCPUFA的优先摄取，这很可能是通过pFABPpm介导的。因此，我们提出p-FABPpm可能参与胎盘对母体血浆LCPUFA的隔离。
