Coukos G, Makrigiannakis A, Amin K, Albelda S M, Coutifaris C
Department of Obstetrics and Gynecology, University of Pennsylvania Medical Center, Philadelphia 19104-4283, USA.
Mol Hum Reprod. 1998 Apr;4(4):357-67. doi: 10.1093/molehr/4.4.357.
The terminal event in the establishment of the haemochorial placenta in the human is the invasion of trophoblasts into the maternal vessels, a process in which trophoblasts interact directly with the vascular endothelium and degrade the vascular basement membrane and the tunica elastica of the vessels. To further understand this heterotypic cellular interaction, we investigated the expression by human trophoblasts of the vascular cell adhesion molecule platelet-endothelial cell adhesion molecule-1 (PECAM-1) as a possible mediator of the adhesive interaction between trophoblasts and endothelium. In vitro, human trophoblasts were found to express PECAM-1 mRNA and protein. Indirect immunofluorescence indicated a diffuse staining pattern, which was most intense in a subpopulation of trophoblast cells. Co-incubation of trophoblasts with endothelial cells showed interaction between these two cell types with strong expression of PECAM-1 at points of trophoblast-endothelial cell contact, suggesting that this cell adhesion molecule participates in this heterotypic cell interaction. Immunohistochemical localization of PECAM-1 in chorionic villi and first trimester implantation sites showed that, in vivo, only extravillous interstitial and endovascular trophoblasts were positive. In first trimester placentae, villous trophoblast and extravillous trophoblast in other locations than around or within the decidual vessels did not express this molecule. In term placentae, villous trophoblast did not express these adhesion molecules except for two specimens examined. This study demonstrates that PECAM-1 is expressed by a subset of human trophoblasts in vitro and in vivo. Its tissue localization suggests that PECAM-1 is important in mediating the adhesive interaction between trophoblasts and maternal vascular endothelium during the process of haemochorial placentation. Regulation of PECAM-1 expression by human trophoblasts may play a critical role in normal and abnormal vascular invasion during implantation and placentation.
人类血绒毛膜胎盘形成过程中的终末事件是滋养层细胞侵入母体血管，在此过程中，滋养层细胞直接与血管内皮相互作用，降解血管基底膜和血管的弹性膜。为了进一步了解这种异型细胞间相互作用，我们研究了人类滋养层细胞对血管细胞黏附分子血小板内皮细胞黏附分子-1（PECAM-1）的表达情况，其可能作为滋养层细胞与内皮细胞间黏附相互作用的介质。在体外，发现人类滋养层细胞表达PECAM-1 mRNA和蛋白。间接免疫荧光显示出弥漫性染色模式，在一部分滋养层细胞中最为强烈。滋养层细胞与内皮细胞共同孵育显示这两种细胞类型之间存在相互作用，在滋养层细胞与内皮细胞接触点处PECAM-1表达强烈，表明这种细胞黏附分子参与了这种异型细胞间相互作用。PECAM-1在绒毛膜绒毛和孕早期着床部位的免疫组织化学定位显示，在体内，只有绒毛外间质和血管内滋养层细胞呈阳性。在孕早期胎盘，除了蜕膜血管周围或血管内的其他部位的绒毛滋养层和绒毛外滋养层不表达该分子。在足月胎盘中，除了检测的两个标本外，绒毛滋养层不表达这些黏附分子。本研究表明，PECAM-1在体外和体内均由一部分人类滋养层细胞表达。其组织定位表明，PECAM-1在血绒毛膜胎盘形成过程中介导滋养层细胞与母体血管内皮之间的黏附相互作用中起重要作用。人类滋养层细胞对PECAM-1表达的调节可能在着床和胎盘形成过程中的正常和异常血管侵入中起关键作用。
