2006 — 2009 |
Ko, Chemyong |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Endothelin-2 in Ovarian Follicle Rupture
[unreadable] DESCRIPTION (provided by applicant): 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. [unreadable] [unreadable] [unreadable]
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0.961 |
2014 — 2018 |
Ko, Chemyong Jay |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. |
Mechanism of Periovulatory Leukocyte Infiltration Into the Ovary
PROJECT SUMMARY (See instructions): Crosstalk between the immune and reproductive systems dramatically impacts fertility. In particular, studies have shown that a tight spatiotemporal control of leukocyte infiltration into the ovary is pivotal for successful ovulation. Once infiltrated, the leukocytes differentiate into a cohort of pro- or anti-infiammatory cells in the preovulatory ovary and play critical roles in ovulation and luteal formation. In this study, we will test the hypothesis that progesterone (P4) and prostaglandins (PG) play pivotal roles in recruiting leukocytes into the preovulatory ovary. Aim 1. To determine the mechanism(s) by which P4 and PG regulate WBC infiltration. We will first determine the roles of P4 and PG on WBC infiltration by treating cycling adult rats with RU486, indomethacin and vehicle, and measuring the effect on the numbers, populations and localization of infiltrating WBC by flow cytometry and immunohistochemistry together with a functional analysis of the expression of chemokines, cytokines, their receptors and cell adhesion molecules (CAMs) in serum, on ovarian cells and WBC by ELISA and qPCR. Aim 2. To determine whether P4 and PG regulate WBC infiltration in primate ovary. In this Aim, we will investigate P4 and PG regulated WBC infiltration in primates. Similar to rodents, primates, including humans also require P4 and PG for normal ovulation. Therefore, we hypothesize that P4 and PG will regulate WBC infiltration in the primate ovary. The actions of P4 and PG will be inhibited by treating primates (Cynomolgous monkeys) with trilostane (3|3HSD inhibitor; inhibits progesterone synthesis), celecoxib (selective COX-2 inhibitor) or vehicle under ovarian stimulation. The effects on the numbers, populations and localization of WBC together with the expression of infiammatory mediators will be determined. Upon the identification of the P4- and PG-regulated WBC subtypes and infiammatory mediators in the monkey, the localization and expression patterns of their homologs will be determined in the human ovary. Aim 3. To determine the regulatory mechanism of preovulatory splenic WBC release. We will identify the trigger(s) and the mechanism of action of splenic WBC release from spleen. We hypothesize that either LH, decreased concentration of circulating WBC or angiotensin-ll (the only known trigger of splenic leukocyte release) act as the trigger. To identify the trigger(s), ovariectomized rats will be treated with candidate triggers (LH and angiotensin-ll) or artificially reduce the concentration of circulating WBC by perfusing rats with plasma. The effects on splenic WBC release will be measured by counting WBC numbers in spleen and peripheral blood.
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0.919 |
2018 — 2019 |
Ko, Chemyong Jay |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Conversion of Eralpha Cells to Erbeta Cells in a Cell Lineage @ University of Illinois At Urbana-Champaign
PROJECT SUMMARY / ABSTRACT This study aims to test the hypothesis that an ESR1-expressing cell can be converted to an ESR2-expressing cell and investigate the molecular mechanism that controls the switch. 17??estradiol (E2) is the key sex hormone regulating development and function of reproductive organs. While two estrogen receptors, ESR1 and ESR2, are well known to be responsible for the classical actions of E2, recent investigations into the functional role of ESR2 show that E2 elicits physiological responses from ESR2-expressing cells that are often completely opposite to those from ESR1-expressing cells. Importantly, while ESR1- and ESR2-expressing cells are co-existent in most of estrogen-responsive organs or tissues, ESR1 and ESR2 are expressed in different cell types. For example, ESR1 is expressed in the surface epithelium and theca cells in the ovary, whereas ESR2 is expressed exclusively in the granulosa cells (GC). No ovarian cell expresses both receptors. We recently made an unexpected observation during a characterization of a transgenic mouse line (Esr1iCreEsr2flox/flox) in which the Esr2 gene was designed to be ablated by a Cre recombinase whose expression was regulated by the endogenous Esr1 gene promoter. In other words, in this transgenic mouse line, the Esr2 gene was deleted in the ESR1 lineage cells. Surprisingly, we found that these transgenic mice were completely deficient of ESR2 expression in the granulosa cells, which otherwise express ESR2 abundantly. This finding indicates that GC lineage cells express ESR1 for some period prior to beginning to express ESR2, evidence of a conversion of ESR1 to ESR2 in the GC lineage. In this study, we will determine exactly when the ESR1 to ESR2 conversion occurs and what underlying mechanism controls the ESR1 and ESR2 expression, using novel transgenic mouse lines that the PI's laboratory generated.
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0.958 |