Kirkup K M, Mallin A M, Bagnell C A
Department of Animal Sciences, Rutgers, The State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA.
J Reprod Fertil. 2000 Nov;120(2):275-81.
Epithelial cadherin (E-cadherin) is a member of the cadherin family of calcium-dependent cell adhesion molecules and is present in the ovary. Although expression of E-cadherin is high in healthy pig granulosa cells and low in granulosa cells of atretic follicles, the importance of E-cadherin-mediated adhesion in granulosa cell function is unclear. The aim of the present study was to determine the impact of immunoneutralization of E-cadherin on granulosa cell adhesion, DNA synthesis and cell proliferation in vitro. Before attachment, pig granulosa cells were exposed to a monoclonal E-cadherin antibody (DECMA-1) which blocks E-cadherin function. Controls included substitution of the antibody with either mouse ascites fluid or another E-cadherin antibody directed against the cytoplasmic domain and which was therefore inaccessible in intact cells. Both granulosa cell proliferation and insulin-like growth factor I-induced DNA synthesis were inhibited significantly in the presence of DECMA-1 compared with controls (P < 0.05). Control granulosa cells in culture formed large clusters with many cells packed tightly together. However, after 48 h exposure to the function-perturbing E-cadherin antibody, there was a significant decrease in the size of the granulosa cell clusters (P < 0.05) and the degree of cell-cell contact was reduced compared with control cultures. No effects on DNA synthesis, cell proliferation or cell adhesion were observed when DECMA-1 was substituted with either mouse ascites fluid or the antibody specific for the cytoplasmic domain of E-cadherin. In conclusion, these data provide evidence to support the hypothesis that E-cadherin is important for maintaining granulosa cell contact, DNA synthesis and cell proliferation in vitro. These results indicate that E-cadherin plays a fundamental role in maintaining both the structure and function of ovarian follicles.
上皮钙黏蛋白（E-钙黏蛋白）是钙依赖性细胞黏附分子钙黏蛋白家族的成员，存在于卵巢中。虽然E-钙黏蛋白在健康猪颗粒细胞中表达较高，而在闭锁卵泡的颗粒细胞中表达较低，但E-钙黏蛋白介导的黏附在颗粒细胞功能中的重要性尚不清楚。本研究的目的是确定E-钙黏蛋白免疫中和对体外颗粒细胞黏附、DNA合成和细胞增殖的影响。在贴壁前，将猪颗粒细胞暴露于阻断E-钙黏蛋白功能的单克隆E-钙黏蛋白抗体（DECMA-1）。对照组包括用小鼠腹水或另一种针对细胞质结构域的E-钙黏蛋白抗体替代该抗体，因此在完整细胞中该抗体无法发挥作用。与对照组相比，在DECMA-1存在的情况下，颗粒细胞增殖和胰岛素样生长因子I诱导的DNA合成均受到显著抑制（P<0.05）。培养中的对照颗粒细胞形成大的细胞簇，许多细胞紧密聚集在一起。然而，在暴露于功能干扰性E-钙黏蛋白抗体48小时后，颗粒细胞簇的大小显著减小（P<0.05），与对照培养物相比，细胞间接触程度降低。当用小鼠腹水或E-钙黏蛋白细胞质结构域特异性抗体替代DECMA-1时，未观察到对DNA合成细胞增殖或细胞黏附的影响。总之，这些数据提供了证据支持以下假设：E-钙黏蛋白对于维持体外颗粒细胞接触、DNA合成和细胞增殖很重要。这些结果表明，E-钙黏蛋白在维持卵巢卵泡的结构和功能方面起着重要作用。
