Inhibition of pig granulosa cell adhesion and growth in vitro by immunoneutralization of epithelial cadherin.
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.
Kirkup
K M
KM
Department of Animal Sciences, Rutgers, The State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA.
Mallin
A M
AM
Bagnell
C A
CA
D000704:Analysis of Variance; D000818:Animals; D015820:Cadherins / Q000276:immunology / Q000502:physiology*; D002448:Cell Adhesion; D002455:Cell Division; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D005260:Female; D006107:Granulosa Cells / Q000166:cytology / Q000502:physiology*; D007106:Immune Sera / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D013552:Swine
D015820:Cadherins; D007106:Immune Sera; D004247:DNA