Submission Number: RAV-4-1-11

Abstract Number: 74

GLUCOCORTICOIDS ENHANCE STEROIDOGENESIS AND REDUCE APOPTOSIS IN HUMAN GRANULOSA CELLS.

Sasson Ravid ¹, Hosokawa Kumiko ^1,2, Ada Dantes ¹, Jung Young Sun ¹, Barash Amihai ³, Granot Irit ³ and Abraham Amsterdam ¹

Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel ¹
Dept of Obstetrics and Gynecology, Fukui Medical University, Fukui 910-1193, Japan ²
Dept of Obstetrics and Gynecology, Kaplan Hospital, Rehovot, Israel ³

Abstract:
The role of glucocorticoids on ovarian steroidogenesis and apoptosis was studied in a human granulosa cell (GC) line and in primary human preovulatory GC. The human GC line (HO-23) was established by triple transfection of cells obtained from IVF patients with SV40, Ha-Ras oncogene and a temperature sensitive mutant of the tumor suppressor gene p53 (p53 Val 135). Primary cultures and immortalized human and rat GC were stimulated with forskolin (20mM) in the presence and absence of 10-100 nM of dexamethasone (Dex) or hydrocortisone for 24-48h. Addition of Dex (30 nM) or hydrocortisone (30 nM) to HO-23 cells or to human preovulatory GC caused a synergistic effect on gonadotropin/cAMP induced progesterone production. Dex dramatically inhibited apoptosis in HO-23 and primary GC, exerted by serum deprivation, activation of p53 or by excess of cAMP stimulation. This effect was abolished by RU-486, indicating the presence of glucocorticoid receptor (GR) in GC. In Western blot analysis, following Dex stimulation, we observed a 2 time increase in total cadherin expression using anti Pan-cadherin antibodies and 4 fold increase in connexin (cx) synthesis using anti cx-43 antibodies. Dex treatment increased formation of adherence junction as revealed by electron microscop of ultrathin sections. Dex also increased formation of the anti apoptotic gene product BCL-2. In contrast to granulosa cells, i.e typical epithelial cells, Dex induced apoptosis in M1 myeloid leukemia cells, which are mesenchimal cells, and this effect involves marked reduction in expression of GR and BCL-2. We suggest that protection of granulosa cells from apoptosis by glucocorticoids is achieved by enhancement of cell contacts and intercellular communication, stabilization of actin cytoskeleton, by up regulation of BCL-2 expression and depends on the cell type. .

Keywords: dexamethasone , BCL-2 , apoptosis, granulosa

This abstract is being presented at: 8:00 AM in session:
Apoptosis