Hirano T, Higuchi T, Ueda M, Inoue T, Kataoka N, Maeda M, Fujiwara H, Fujii S
Department of Gynecology and Obstetrics, Faculty of Medicine, Kyoto University, Japan.
Mol Hum Reprod. 1999 Feb;5(2):162-7. doi: 10.1093/molehr/5.2.162.
The CD9 molecule is a 24-27 kDa cell surface glycoprotein, which may be related to Schwann cell migration and adhesion. In this study, we examined the expression of CD9 in human extravillous trophoblasts, which invade into the endometrium during implantation and placentation. CD9 was detected immunohistochemically on the extravillous trophoblasts in the cell columns of first trimester placentae, but not on villous trophoblasts. In the second and third trimester, CD9 was highly expressed on the extravillous trophoblasts in the basal plate of placentae, and in the chorion laeve in the fetal membrane of term placentae. The molecular mass of CD9 in the chorion laeve was shown to be 27 kDa by Western blotting. The mRNA of CD9 was also detected in the chorion laeve by reverse transcription-polymerase chain reaction (RT-PCR). Proteins were purified from chorion laeve by affinity chromatography with anti-integrin alpha3 and alpha5 monoclonal antibodies and Western blotting, revealed that CD9 was associated with both integrins. These findings indicate that CD9 is a differentiation-related molecule present in the extravillous trophoblasts. Since it is associated with integrin alpha5 which has been proposed to regulate trophoblast invasion, CD9 may be implicated in trophoblast invasion at the feto-maternal interface.
CD9分子是一种24 - 27 kDa的细胞表面糖蛋白，可能与雪旺细胞迁移和黏附有关。在本研究中，我们检测了CD9在人绒毛外滋养层细胞中的表达，这些细胞在植入和胎盘形成过程中侵入子宫内膜。免疫组织化学检测发现，CD9在孕早期胎盘细胞柱中的绒毛外滋养层细胞上有表达，但在绒毛滋养层细胞上未检测到。在孕中期和孕晚期，CD9在胎盘基底板的绒毛外滋养层细胞以及足月胎盘胎膜的平滑绒毛膜中高表达。通过蛋白质印迹法显示，平滑绒毛膜中CD9的分子量为27 kDa。通过逆转录-聚合酶链反应（RT-PCR）也在平滑绒毛膜中检测到了CD9的mRNA。用抗整合素α3和α5单克隆抗体通过亲和层析从平滑绒毛膜中纯化蛋白质，蛋白质印迹法显示CD9与这两种整合素都有关联。这些发现表明，CD9是存在于绒毛外滋养层细胞中的一种与分化相关的分子。由于它与已被提出可调节滋养层细胞侵袭的整合素α5有关联，CD9可能在母胎界面的滋养层细胞侵袭中起作用。
