Taylor R N, Newman E D, Chen S A
Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco 94143-0132.
Am J Obstet Gynecol. 1991 Jan;164(1 Pt 1):204-10. doi: 10.1016/0002-9378(91)90654-a.
The human placenta and its associated membranes are vital to the maintenance, nutrition, and protection of the developing fetus. During placental development some cytotrophoblasts give rise to the chorionic membrane whereas others fuse to form a differentiated syncytium of cells that are responsible for placental protein and steroid hormone production. The mechanisms involved in the differentiation of the trophoblasts are unknown; however, an intermediate stage with a characteristic phenotype has been documented in vivo. We have observed that chemically dissimilar xenobiotic agents induced BeWo choriocarcinoma cells to change their usual cytotrophoblastic phenotype and acquire morphologic and functional characteristics typical of intermediate trophoblast. Incubation of BeWo cell cultures in the presence of 1 mumol/L methotrexate for 48 hours stimulated human chorionic gonadotropin secretion (2.3-fold) and aromatase activity (4.9-fold). Morphologic findings associated with these hormonal changes, including increased nuclear size and cytoplasmic expansion, were also observed. With the use of a computer-interfaced image analyzer, planimetric morphometry of the nuclear area of the cells revealed a 1.8-fold increase after incubation with methotrexate. The effect of forskolin, a direct activator of adenylyl cyclase, was also evaluated by means of this model of cytotrophoblast differentiation. The addition of 10 mumol/L forskolin to BeWo cultures also resulted in dramatic changes in trophoblast cell phenotype. Increases in human chorionic gonadotropin synthesis (7.3-fold), aromatase activity (13.5-fold), and nuclear area (3.0-fold) were induced over those of untreated cells. In addition, increases in [3H]thymidine incorporation (1.7-fold) were afforded by both treatments. These results suggest that biochemical and cytologic changes associated with human trophoblast differentiation can be induced in vitro via activation of the adenylyl cyclase pathway by forskolin and through unknown and apparently independent signals by methotrexate.
人类胎盘及其相关膜对于发育中胎儿的维持、营养供应和保护至关重要。在胎盘发育过程中，一些细胞滋养层细胞形成绒毛膜，而另一些则融合形成一种分化的细胞合体，负责胎盘蛋白质和甾体激素的产生。滋养层细胞分化所涉及的机制尚不清楚；然而，体内已记录到具有特征性表型的中间阶段。我们观察到，化学性质不同的外源性物质可诱导BeWo绒毛膜癌细胞改变其通常的细胞滋养层表型，并获得中间滋养层典型的形态和功能特征。在1 μmol/L甲氨蝶呤存在下将BeWo细胞培养物孵育48小时，可刺激人绒毛膜促性腺激素分泌（2.3倍）和芳香化酶活性（4.9倍）。还观察到与这些激素变化相关的形态学改变，包括核尺寸增大和细胞质扩张。使用计算机接口图像分析仪对细胞的核面积进行平面形态测量，结果显示与甲氨蝶呤孵育后核面积增加了1.8倍。通过这种细胞滋养层分化模型，还评估了腺苷酸环化酶直接激活剂福斯高林的作用。向BeWo培养物中添加10 μmol/L福斯高林也导致滋养层细胞表型发生显著变化。与未处理细胞相比，人绒毛膜促性腺激素合成增加（7.3倍）、芳香化酶活性增加（13.5倍）以及核面积增加（3.0倍）。此外，两种处理均使[3H]胸腺嘧啶核苷掺入增加（1.7倍）。这些结果表明，与人类滋养层细胞分化相关的生化和细胞学变化可在体外通过福斯高林激活腺苷酸环化酶途径以及通过甲氨蝶呤未知且明显独立的信号诱导产生。
