Knipp G T, Liu B, Audus K L, Fujii H, Ono T, Soares M J
Department of Molecular and Integrative Physiology, The University of Kansas Medical Center, 39 011 Rainbow Boulevard, Kansas City, Kansas, 66160, USA.
Placenta. 2000 May;21(4):367-75. doi: 10.1053/plac.1999.0484.
The placenta forms a selective barrier that is able to transport nutrients that are of critical use to the fetus. Delivery of essential fatty acids to the fetus is dependent upon transplacental transport and provides the backbone for the biosynthesis of biological membranes, myelin and various signalling molecules. The primary objective of this research was to elucidate the expression patterns of genes that regulate fatty acid transport across the placenta. Several fatty acid transport regulatory genes have been identified in the rat including; cytoplasmic heart fatty acid binding protein (hFABP), plasma membrane fatty acid binding protein (FABPpm), fatty acid translocase (FAT) and fatty acid transport protein (FATP). In this study, we have elucidated temporal and spatial expression patterns for these genes in the rat placenta and in cell culture models of the rat placenta by Northern blot, RT-PCR, Western blot and/or by in situ hybridization analyses. Expression of hFABP was specific to the labyrinth zone, the main barrier and site of transplacental transport in the rat placenta. In addition, the levels of hFABP expression increased with gestational age, suggesting a growing requirement for fatty acid transport with advancing stages of pregnancy. FABPpm, FAT and FATP are expressed in both the junctional and labyrinth zones of the rat placenta. FAT was predominantly localized to the labyrinth zone by in situ hybridization analysis. The placental cell expression patterns of the genes involved in fatty acid transport were supported by our observations of HRP-1 (labyrinth zone) and Rcho-1 (junctional zone) trophoblast cell culture models. Given their cell surface location, we predict that FABPpm, FAT and FATP potentially participate in placental fatty acid uptake. The predominant expression of hFABP and FAT in the labyrinth zone of the chorioallantoic placenta implicates hFABP and FAT in the transplacental movement of fatty acids from maternal to fetal compartments.
胎盘形成了一个选择性屏障，能够转运对胎儿至关重要的营养物质。必需脂肪酸向胎儿的输送依赖于经胎盘转运，并为生物膜、髓磷脂和各种信号分子的生物合成提供了基础。本研究的主要目的是阐明调节脂肪酸跨胎盘转运的基因的表达模式。在大鼠中已经鉴定出几种脂肪酸转运调节基因，包括细胞质心脏脂肪酸结合蛋白（hFABP）、质膜脂肪酸结合蛋白（FABPpm）、脂肪酸转位酶（FAT）和脂肪酸转运蛋白（FATP）。在本研究中，我们通过Northern印迹、RT-PCR、Western印迹和/或原位杂交分析，阐明了这些基因在大鼠胎盘以及大鼠胎盘细胞培养模型中的时空表达模式。hFABP的表达在大鼠胎盘的迷路区具有特异性，迷路区是大鼠胎盘经胎盘转运的主要屏障和部位。此外，hFABP的表达水平随着胎龄增加而升高，这表明随着妊娠进展，对脂肪酸转运的需求不断增加。FABPpm、FAT和FATP在大鼠胎盘的连接区和迷路区均有表达。原位杂交分析显示，FAT主要定位于迷路区。我们对HRP-1（迷路区）和Rcho-1（连接区）滋养层细胞培养模型的观察结果支持了参与脂肪酸转运的基因在胎盘细胞中的表达模式。鉴于它们在细胞表面的位置，我们预测FABPpm、FAT和FATP可能参与胎盘脂肪酸的摄取。绒毛膜尿囊胎盘迷路区中hFABP和FAT的主要表达表明hFABP和FAT参与了脂肪酸从母体向胎儿区室的经胎盘转运。
