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 vasoconstrice 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 interdisplinary approachs (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.
| Cacioppo, Joseph A; Lin, Po-Ching Patrick; Hannon, Patrick R et al. (2017) Granulosa cell endothelin-2 expression is fundamental for ovulatory follicle rupture. Sci Rep 7:817 |
| Cacioppo, Joseph A; Koo, Yongbum; Lin, Po-Ching Patrick et al. (2016) Generation of an estrogen receptor beta-iCre knock-in mouse. Genesis 54:38-52 |
| Cacioppo, Joseph A; Koo, Yongbum; Lin, Po-Ching Patrick et al. (2015) Generation and characterization of an endothelin-2 iCre mouse. Genesis 53:245-56 |
| Cacioppo, Joseph A; Oh, Sang Wook; Kim, Hey-young et al. (2014) Loss of function of endothelin-2 leads to reduced ovulation and CL formation. PLoS One 9:e96115 |
| Cho, Jongki; Kim, Heyyoung; Kang, Dong-Wook et al. (2012) Endothelin B receptor is not required but necessary for finite regulation of ovulation. Life Sci 91:613-7 |
| Bridges, Phillip J; Jeoung, Myoungkun; Kim, Heyoung et al. (2011) Methodology matters: IVF versus ICSI and embryonic gene expression. Reprod Biomed Online 23:234-44 |
| Oakley, Oliver R; Frazer, Michele L; Ko, CheMyong (2011) Pituitary-ovary-spleen axis in ovulation. Trends Endocrinol Metab 22:345-52 |
| Choi, Dong-Hee; Kim, Eun Kyung; Kim, Kyeoung-Hwa et al. (2011) Expression pattern of endothelin system components and localization of smooth muscle cells in the human pre-ovulatory follicle. Hum Reprod 26:1171-80 |
| Kim, Hyun Joon; Gieske, Mary C; Trudgen, Kourtney L et al. (2011) Identification of estradiol/ER?-regulated genes in the mouse pituitary. J Endocrinol 210:309-21 |
| Bridges, Phillip J; Cho, Jongki; Ko, CheMyong (2011) Endothelins in regulating ovarian and oviductal function. Front Biosci (Schol Ed) 3:145-55 |
Showing the most recent 10 out of 19 publications
