Endothelin-2 In Ovarian Follicle Rupture
Chemyong Ko
University Of Kentucky 109 Kinkead Hall Lexington, Ky 405060057
Grant 1R01HD052694-01 from National Institute Of Child Health And Human Development IRG: CMIR
Abstract: The goal of the proposed studies is to elucidate the mechanism of endothelin-2 (EDN-2) action in follicle rupture. The program of ovulation is activated by a surge of luteinizing hormone, which initiates dramatic changes in molecular, biochemical, and physical aspects of the ovary, eventually leading to rupture of follicles. However, the factors involved in and the mechanism governing the process of follicle rupture are yet to be unveiled. Using a gene expression profiling approach, we have identified EDN-2, a potent smooth muscle constrictor, which is exclusively and transiently expressed in the granulosa cells of periovulatory follicles immediately prior to ovulation. We found that EDN-2 induces rapid and sustained contraction in the ovarian tissue, while tezosentan, an endothelin receptor antagonist, released the contraction. These novel findings led us to hypothesize that EDN-2 directly constricts periovulatory follicles leading to the rupture of the follicle. Supporting the hypothesis, immunohistochemical analysis identified a well-organized smooth muscle layer in the theca externa of each follicle, which forms a sponge-like smooth muscle network at the whole ovarian level. Furthermore, we found that intraovarian injection of tezosentan prior to ovulation completely blocked follicle rupture. In this study, we will elucidate the mechanism of EDN-2 action in follicle rupture. We will determine the target tissues of EDN-2 action, the endothelin receptor subtype(s) that mediates EDN-2 action, and the ovarian concentration of EDN-2. We will also determine the mechanism of endothelin-2 induced follicular constriction in relation to other ovary-produced vasoconstrictive molecules (VIPs, PACAPs, and prostaglandins). In addition, the functional link of progesterone, estrogen, and prostaglandin to the follicle rupture in relation to EDN-2 will be explored. The major strength of this proposal is in the identification of EDN-2 and the ovarian smooth muscle network as the key components of follicle rupture. The novelty of the proposed experiments is the interdisciplinary approaches (genome-wide gene expression profiling, intraovarian injection, and isometric tension measurement). The proposed studies are exceptionally important in order to further our understanding of the mechanism of follicle rupture. The proposed experiments will provide clinical direction in identifying the therapeutic target for the cure of annovulatory symptoms, one of the leading causes of female infertility.
Keywords: corpus luteum, disease /disorder etiology, endothelin, female reproductive system disorder, hormone regulation /control mechanism, ovulation, binding site, estrogen receptor, hormone metabolism, hormone receptor, muscle contraction, peptide, progesterone receptor, prostaglandin, protein structure function, receptor expression, smooth muscle, autoradiography, genetically modified animal, immature animal, immunocytochemistry, in situ hybridization, laboratory mouse, laboratory rat, mature animal, radioimmunoassay
Project start date: 2006-05-15
Project end date: 2011-02-28
1R01HD052694-01 (2006): $243135
Sponsored Links Excellgen http://Excellgen.com
Grants awarded to Chemyong Ko
Endothelin-2 In Ovarian Follicle Rupture
Chemyong Ko
University Of Kentucky 109 Kinkead Hall Lexington, Ky 405060057
Grant 5R01HD052694-02 from National Institute Of Child Health And Human Development IRG: CMIR
Abstract: The goal of the proposed studies is to elucidate the mechanism of endothelin-2 (EDN-2) action in follicle rupture. The program of ovulation is activated by a surge of luteinizing hormone, which initiates dramatic changes in molecular, biochemical, and physical aspects of the ovary, eventually leading to rupture of follicles. However, the factors involved in and the mechanism governing the process of follicle rupture are yet to be unveiled. Using a gene expression profiling approach, we have identified EDN-2, a potent smooth muscle constrictor, which is exclusively and transiently expressed in the granulosa cells of periovulatory follicles immediately prior to ovulation. We found that EDN-2 induces rapid and sustained contraction in the ovarian tissue, while tezosentan, an endothelin receptor antagonist, released the contraction. These novel findings led us to hypothesize that EDN-2 directly constricts periovulatory follicles leading to the rupture of the follicle. Supporting the hypothesis, immunohistochemical analysis identified a well-organized smooth muscle layer in the theca externa of each follicle, which forms a sponge-like smooth muscle network at the whole ovarian level. Furthermore, we found that intraovarian injection of tezosentan prior to ovulation completely blocked follicle rupture. In this study, we will elucidate the mechanism of EDN-2 action in follicle rupture. We will determine the target tissues of EDN-2 action, the endothelin receptor subtype(s) that mediates EDN-2 action, and the ovarian concentration of EDN-2. We will also determine the mechanism of endothelin-2 induced follicular constriction in relation to other ovary-produced vasoconstrictive molecules (VIPs, PACAPs, and prostaglandins). In addition, the functional link of progesterone, estrogen, and prostaglandin to the follicle rupture in relation to EDN-2 will be explored. The major strength of this proposal is in the identification of EDN-2 and the ovarian smooth muscle network as the key components of follicle rupture. The novelty of the proposed experiments is the interdisciplinary approaches (genome-wide gene expression profiling, intraovarian injection, and isometric tension measurement). The proposed studies are exceptionally important in order to further our understanding of the mechanism of follicle rupture. The proposed experiments will provide clinical direction in identifying the therapeutic target for the cure of annovulatory symptoms, one of the leading causes of female infertility.
Keywords: endothelin, injury, Porifera, binding site, egg /ovum, estrogen, estrogen receptor, fallopian tube, female, fertility, gene, gene expression, gene expression profiling, genetically modified animal, genome, gonadotropin, granulosa cell, immunocytochemistry, in situ hybridization, indomethacin, information system, laboratory mouse, lead, luteinizing hormone, measurement, model, muscle, ovary, ovary disorder, ovulation, peptide, progesterone, progesterone receptor, prostaglandin, radioimmunoassay, receptor, role, smooth muscle, success, syndrome, tissue
Project start date: 2006-05-15
Project end date: 2011-02-28
5R01HD052694-02 (2007): $236137
5R01HD052694-05 (2010): $229100