Preferential uptake of long chain polyunsaturated fatty acids by isolated human placental membranes
Preferential uptake of long chain polyunsaturated fatty acids by isolated human placental membranes
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DOI：
10.1007/bf00714336
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发表时间：
1996-02-09
影响因子：
4.3
通讯作者：
DuttaRoy, AK
中科院分区：
文献类型：
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作者：
Campbell, FM;Gordon, MJ;DuttaRoy, AK
胎盘对脂肪酸的摄取被认为是一个载体介导的过程，然而，长链多不饱和脂肪酸（LCPUFA）优先从母体循环累积到胎儿组织的机制尚不清楚。为了检查胎盘在该过程中的作用，研究了四种不同放射性标记的脂肪酸（[C-14]油酸酯、[C-14]亚油酸酯、[C-14] α-亚麻酸酯和[C-14]花生四烯酸酯）与人胎盘膜的结合。脂肪酸的结合被认为是时间和温度依赖性的。在平衡时，油酸酯的总结合最高（5.1 +/- 0.1纳摩尔/毫克蛋白质），其次是亚油酸酯（2.8 +/- 0.31纳摩尔/毫克蛋白质）和花生四烯酸酯（2.06 +/- 0.4纳摩尔/毫克蛋白质），α-亚麻酸酯结合最低（0.5 + 0.1纳摩尔/毫克蛋白质）。然而，油酸酯具有最低的特异性结合（总结合的37%），而花生四烯酸酯具有最高的特异性结合（类似于总结合的86%），其次是亚油酸酯和α-亚麻酸酯（分别为总结合的62%和69%）。还在20倍过量的其他未标记配体存在下评估了每种[C-14]脂肪酸的结合。结合位点似乎对[C-14]脂肪酸的结合具有以下顺序的偏好：花生四烯酸>亚油酸>> α-亚麻酸>油酸，而BSP和α-生育酚没有显示出与任何[C-14]脂肪酸的任何竞争。这些数据表明，胎盘膜中的脂肪酸结合位点对脂肪酸是特异性的，但它们具有异质性亲和力。反式脂肪酸（反油酸和亚油酸）也非常强烈地竞争[C-14]脂肪酸结合。针对胎盘FABP（pm）产生的多克隆抗血清抑制了这些[C-14]脂肪酸的结合，但抑制程度不同; EFA/LCPUFA的结合远高于油酸。我们的数据表明，结合到白蛋白的EFA/LCPUFA优先通过人胎盘膜转运，胎盘FABP（pm）可能参与胎盘对EFA/LCPUFA的隔离。
Fatty acid uptake by the placenta is thought to be a carrier-mediated process, however the mechanism by which long chain polyunsaturated fatty acids (LCPUFA) are preferentially accumulated from the maternal circulation to the fetal tissues is still unclear. To examine the role of the placenta in this process, binding of four different radiolabelled fatty acids ([C-14]oleate, [C-14]linoleate, [C-14]a-linolenate and [C-14]arachidonate) to human placental membranes was studied. Binding of fatty acid was found to be time- and temperature dependent. At equilibrium, the total binding of oleate was highest (5.1 +/- 0.1 nmoles/mg protein) followed by linoleate (2.8 +/- 0.31 nmoles/mg protein) and arachidonate (2.06 +/- 0.4 nmoles/mg protein) and alpha-linolenate binding was lowest (0.5 + 0.1 nmoles/mg protein). However, oleate had the lowest specific binding (37% of the total binding) whereas arachidonate had the highest specific binding (similar to 86% of the total binding) followed by linoleate and a-linolenate (62%, and 69% of the total binding, respectively). Binding of each [C-14] fatty acid was also assessed in the presence of 20-fold excess of other unlabelled ligands. Binding sites seem to have preference for the binding of [C-14] fatty acids in the following order: arachidonic acid >>> linoleic acid >> a-linolenic acid >>>>> oleic acid, whereas BSP and a-tocopherol did not show any competition with any of the [C-14] fatty acids. These data suggest that the fatty acid binding sites in placental membranes are specific for the fatty acids but that they have heterogeneous affinities. Trans fatty acids (elaidic and linoelaidic acids) also competed very strongly for the [C-14] fatty acid binding. Polyclonal antiserum raised against placental FABP(pm) inhibited binding of these [C-14]fatty acids but with variable degrees of inhibition; EFA/LCPUFA binding was much more than that of oleate. Our data suggest that EFA/LCPUFA bound to albumin are preferentially transported by human placental membranes and that the placental FABP(pm) may be involved in the sequestration of EFA/LCPUFA by the placenta.