Department of Physiology, University of Siena, Via A. Moro, 53100 Siena, Italy.
Placenta. 2010 May;31(5):423-30. doi: 10.1016/j.placenta.2010.02.015. Epub 2010 Mar 24.
ATP binding cassette transporter A1 (ABCA1) is a membrane transporter which performs cellular efflux of cholesterol and phospholipid. ABCA1's cholesterol transporting role in human placenta appears to be crucial for normal fetal development. Despite the critical importance of cholesterol in fetal development, expression of ABCA1 in the human placenta throughout gestation and its specific cellular localization have not been known yet. We therefore investigated ABCA1 expression in human placenta at first trimester and term by western blot and quantitative real-time PCR (qRT-PCR) analysis. Furthermore, its localization was investigated by immunohistochemistry and confocal microscopy. Expression of ABCA1 did not differ significantly between first trimester and term placenta at both protein and mRNA levels. Immunohistochemical data demonstrated that ABCA1 was widely localized in the villous and extravillous cytotrophoblast as well as in some stromal and endothelial cells. Confocal microscopy imaging data showed that ABCA1 was localized largely at the basolateral and to some extent at the apical side of first trimester villous cytotrophoblast cell membranes. Placental expression of ABCA1 throughout the gestation and its specific cellular localization indicate that this transporter may play an important role in materno-fetal cholesterol transfer.
三磷酸腺苷结合盒转运体 A1（ABCA1）是一种膜转运蛋白，可将胆固醇和磷脂从细胞内排出。ABCA1 在人胎盘内的胆固醇转运作用对于正常胎儿发育似乎至关重要。尽管胆固醇对胎儿发育至关重要，但 ABCA1 在人胎盘内整个妊娠期的表达及其特定的细胞定位尚未可知。因此，我们通过 Western blot 和定量实时 PCR（qRT-PCR）分析研究了 ABCA1 在人胎盘的表达情况。此外，还通过免疫组织化学和共聚焦显微镜研究了其定位。在蛋白质和 mRNA 水平上，ABCA1 在早期妊娠和足月胎盘之间的表达无显著差异。免疫组织化学数据表明，ABCA1 在绒毛和绒毛外滋养细胞以及一些基质和内皮细胞中广泛存在。共聚焦显微镜成像数据表明，ABCA1 主要定位于早期妊娠绒毛滋养细胞的基底外侧，在一定程度上也定位于顶侧。ABCA1 在整个妊娠期的胎盘表达及其特定的细胞定位表明，该转运蛋白可能在母胎胆固醇转移中发挥重要作用。
