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Hsueh YW, Huang CC, Hung SW, Chang CW, Hsu HC, Yang TC, Lin WC, Su SY, Chang HM. Finding of the optimal preparation and timing of endometrium in frozen-thawed embryo transfer: a literature review of clinical evidence. Front Endocrinol (Lausanne) 2023; 14:1250847. [PMID: 37711892 PMCID: PMC10497870 DOI: 10.3389/fendo.2023.1250847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/08/2023] [Indexed: 09/16/2023] Open
Abstract
Frozen-thawed embryo transfer (FET) has been a viable alternative to fresh embryo transfer in recent years because of the improvement in vitrification methods. Laboratory-based studies indicate that complex molecular and morphological changes in endometrium during the window of implantation after exogenous hormones with controlled ovarian stimulation may alter the interaction between the embryo and endometrium, leading to a decreased implantation potential. Based on the results obtained from randomized controlled studies, increased pregnancy rates and better perinatal outcomes have been reported following FET. Compared to fresh embryo transfer, fewer preterm deliveries, and reduced incidence of ovarian hyperstimulation syndrome were found after FETs, yet there is a trend of increased pregnancy-related hypertensive diseases in women receiving FET. Despite the increased application of FET, the search for the most optimal priming protocol for the endometrium is still undergoing. Three available FET protocols have been proposed to prepare the endometrium: i) natural cycle (true natural cycle and modified natural cycle) ii) artificial cycle (AC) or hormone replacement treatment cycle iii) mild ovarian stimulation (mild-OS) cycle. Emerging evidence suggests that the optimal timing for FET using warmed blastocyst transfer is the LH surge+6 day, hCG administration+7 day, and the progesterone administration+6 day in the true natural cycle, modified natural cycle, and AC protocol, respectively. Although still controversial, better clinical pregnancy rates and live birth rates have been reported using the natural cycle (true natural cycle/modified natural cycle) compared with the AC protocol. Additionally, a higher early pregnancy loss rate and an increased incidence of gestational hypertension have been found in FETs using the AC protocol because of the lack of a corpus luteum. Although the common clinical practice is to employ luteal phase support (LPS) in natural cycles and mild-OS cycles for FET, the requirement for LPS in these protocols remains equivocal. Recent findings obtained from RCTs do not support the routine application of endometrial receptivity testing to optimize the timing of FET. More RCTs with rigorous methodology are needed to compare different protocols to prime the endometrium for FET, focusing not only on live birth rate, but also on maternal, obstetrical, and neonatal outcomes.
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Affiliation(s)
- Ya-Wen Hsueh
- Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan
| | - Chien-Chu Huang
- Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan
| | - Shuo-Wen Hung
- Department of Chinese Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Chia-Wei Chang
- Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan
| | - Hsi-Chen Hsu
- Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan
| | - Tung-Chuan Yang
- Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan
| | - Wu-Chou Lin
- Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan
| | - Shan-Yu Su
- Department of Chinese Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Hsun-Ming Chang
- Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan
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Casati L, Ciceri S, Maggi R, Bottai D. Physiological and Pharmacological overview of the Gonadotropin Releasing Hormone. Biochem Pharmacol 2023; 212:115553. [PMID: 37075816 DOI: 10.1016/j.bcp.2023.115553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/07/2023] [Accepted: 04/10/2023] [Indexed: 04/21/2023]
Abstract
Gonadotropin-releasing Hormone (GnRH) is a decapeptide responsible for the control of the reproductive functions. It shows C- and N-terminal aminoacid modifications and two other distinct isoforms have been so far identified. The biological effects of GnRH are mediated by binding to high-affinity G-protein couple receptors (GnRHR), showing characteristic very short C tail. In mammals, including humans, GnRH-producing neurons originate in the embryonic nasal compartment and during early embryogenesis they undergo rapid migration towards the hypothalamus; the increasing knowledge of such mechanisms improved diagnostic and therapeutic approaches to infertility. The pharmacological use of GnRH, or its synthetic peptide and non-peptide agonists or antagonists, provides a valid tool for reproductive disorders and assisted reproduction technology (ART). The presence of GnRHR in several organs and tissues indicates additional functions of the peptide. The identification of a GnRH/GnRHR system in the human endometrium, ovary, and prostate has extended the functions of the peptide to the physiology and tumor transformation of such tissues. Likely, the activity of a GnRH/GnRHR system at the level of the hippocampus, as well as its decreased expression in mice brain aging, raised interest in its possible involvement in neurogenesis and neuronal functions. In conclusion, GnRH/GnRHR appears to be a fascinating biological system that exerts several possibly integrated pleiotropic actions in the complex control of reproductive functions, tumor growth, neurogenesis, and neuroprotection. This review aims to provide an overview of the physiology of GnRH and the pharmacological applications of its synthetic analogs in the management of reproductive and non-reproductive diseases.
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Affiliation(s)
- Lavinia Casati
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | - Samuele Ciceri
- Dept. of Pharmaceutical Sciences (DISFARM), Università degli Studi di Milano, Milano Italy
| | - Roberto Maggi
- Dept. of Pharmaceutical Sciences (DISFARM), Università degli Studi di Milano, Milano Italy.
| | - Daniele Bottai
- Dept. of Pharmaceutical Sciences (DISFARM), Università degli Studi di Milano, Milano Italy
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PASSARELLI A, LETTIERI A, DEMIRCI TN, MAGNI P. Gonadotropin-releasing hormone-secreting neuron development and function: an update. Minerva Endocrinol (Torino) 2022; 47:58-69. [DOI: 10.23736/s2724-6507.22.03683-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wu HM, Chang HM, Leung PCK. Gonadotropin-releasing hormone analogs: Mechanisms of action and clinical applications in female reproduction. Front Neuroendocrinol 2021; 60:100876. [PMID: 33045257 DOI: 10.1016/j.yfrne.2020.100876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/23/2020] [Accepted: 10/04/2020] [Indexed: 12/15/2022]
Abstract
Extra-hypothalamic GnRH and extra-pituitary GnRH receptors exist in multiple human reproductive tissues, including the ovary, endometrium and myometrium. Recently, new analogs (agonists and antagonists) and modes of GnRH have been developed for clinical application during controlled ovarian hyperstimulation for assisted reproductive technology (ART). Additionally, the analogs and upstream regulators of GnRH suppress gonadotropin secretion and regulate the functions of the reproductive axis. GnRH signaling is primarily involved in the direct control of female reproduction. The cellular mechanisms and action of the GnRH/GnRH receptor system have been clinically applied for the treatment of reproductive disorders and have widely been introduced in ART. New GnRH analogs, such as long-acting GnRH analogs and oral nonpeptide GnRH antagonists, are being continuously developed for clinical application. The identification of the upstream regulators of GnRH, such as kisspeptin and neurokinin B, provides promising potential to develop these upstream regulator-related analogs to control the hypothalamus-pituitary-ovarian axis.
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Affiliation(s)
- Hsien-Ming Wu
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou Medical Center, Chang Gung University School of Medicine, Taoyuan 333, Taiwan, ROC
| | - Hsun-Ming Chang
- Department of Obstetrics and Gynaecology, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia V6H 3V5, Canada
| | - Peter C K Leung
- Department of Obstetrics and Gynaecology, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia V6H 3V5, Canada.
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Pillai VV, Siqueira LG, Das M, Kei TG, Tu LN, Herren AW, Phinney BS, Cheong SH, Hansen PJ, Selvaraj V. Physiological profile of undifferentiated bovine blastocyst-derived trophoblasts. Biol Open 2019; 8:bio037937. [PMID: 30952696 PMCID: PMC6550082 DOI: 10.1242/bio.037937] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 03/29/2019] [Indexed: 12/27/2022] Open
Abstract
Trophectoderm of blastocysts mediate early events in fetal-maternal communication, enabling implantation and establishment of a functional placenta. Inadequate or impaired developmental events linked to trophoblasts directly impact early embryo survival and successful implantation during a crucial period that corresponds with high incidence of pregnancy losses in dairy cows. As yet, the molecular basis of bovine trophectoderm development and signaling towards initiation of implantation remains poorly understood. In this study, we developed methods for culturing undifferentiated bovine blastocyst-derived trophoblasts and used both transcriptomics and proteomics in early colonies to categorize and elucidate their functional characteristics. A total of 9270 transcripts and 1418 proteins were identified and analyzed based on absolute abundance. We profiled an extensive list of growth factors, cytokines and other relevant factors that can effectively influence paracrine communication in the uterine microenvironment. Functional categorization and analysis revealed novel information on structural organization, extracellular matrix composition, cell junction and adhesion components, transcription networks, and metabolic preferences. Our data showcase the fundamental physiology of bovine trophectoderm and indicate hallmarks of the self-renewing undifferentiated state akin to trophoblast stem cells described in other species. Functional features uncovered are essential for understanding early events in bovine pregnancy towards initiation of implantation.
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Affiliation(s)
- Viju Vijayan Pillai
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Luiz G Siqueira
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA
- Brazilian Agricultural Research Corporation - Embrapa Gado de Leite, Juiz de Fora, Minas Gerais 36038-330, Brazil
| | - Moubani Das
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Tiffany G Kei
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Lan N Tu
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Anthony W Herren
- Genome Center, Proteomics Core Facility, University of California, Davis, CA 95616, USA
| | - Brett S Phinney
- Genome Center, Proteomics Core Facility, University of California, Davis, CA 95616, USA
| | - Soon Hon Cheong
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Peter J Hansen
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Vimal Selvaraj
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
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Kaprara A, Huhtaniemi IT. The hypothalamus-pituitary-gonad axis: Tales of mice and men. Metabolism 2018; 86:3-17. [PMID: 29223677 DOI: 10.1016/j.metabol.2017.11.018] [Citation(s) in RCA: 168] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 11/28/2017] [Accepted: 11/29/2017] [Indexed: 02/06/2023]
Abstract
Reproduction is controlled by the hypothalamic-pituitary-gonadal (HPG) axis. Gonadotropin-releasing hormone (GnRH) neurons play a central role in this axis through production of GnRH, which binds to a membrane receptor on pituitary gonadotrophs and stimulates the biosynthesis and secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Multiple factors affect GnRH neuron migration, GnRH gene expression, GnRH pulse generator, GnRH secretion, GnRH receptor expression, and gonadotropin synthesis and release. Among them anosmin is involved in the guidance of the GnRH neuron migration, and a loss-of-function mutation in its gene leads to a failure of their migration from the olfactory placode to the hypothalamus, with consequent anosmic hypogonadotropic hypogonadism (Kallmann syndrome). There are also cases of hypogonadotropic hypogonadim with normal sense of smell, due to mutations of other genes. Another protein, kisspeptin plays a crucial role in the regulation of GnRH pulse generator and the pubertal development. GnRH is the main hypothalamic regulator of the release of gonadotropins. Finally, FSH and LH are the essential hormonal regulators of testicular functions, acting through their receptors in Sertoli and Leydig cells, respectively. The main features of the male HPG axis will be described in this review.
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Affiliation(s)
- Athina Kaprara
- Unit of Reproductive Endocrinology, Medical School, Aristotle University of Thessaloniki, Greece.
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Abstract
Gonadotropin-releasing hormone (GnRH) is recognized as the central regulator of the functions of the pituitary-gonadal axis. The increasing knowledge on the mechanisms controlling the development and the function of GnRH-producing neurons is leading to a better diagnostic and therapeutic approach for hypogonadotropic hypogonadisms and for alterations of the puberty onset. During female life span, the function of the GnRH pulse generator may be affected by a number of inputs from other neuronal systems, offering alternative strategies for diagnostic and therapeutic interventions. Moreover, the identification of a GnRH/GnRH receptor system in both human ovary and endometrium has widened the spectrum of action of the peptide outside its hypothalamic functions. The pharmacological use of GnRH itself or its synthetic analogs (agonists and antagonists) provides a valid tool to either stimulate or block gonadotropin secretion and to modulate the female fertility in several reproductive disorders and in assisted reproduction technology. The use of GnRH agonists in young female patients undergoing chemotherapy is also considered a promising therapeutic approach to counteract iatrogenic ovarian failure.
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Siler-Khodr TM, Grayson M. Salmon GnRH and Its Analogues Bind the Human Placental Receptor. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/107155760100800408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Theresa M. Siler-Khodr
- Department of Obstetrics & Gynecology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Room 416E, San Antonio, TX 78284
| | - Marcia Grayson
- Department of Obstetrics & Gynecology, The University of Texas Health Science Centre at San Antomio, San Antonio, Texas
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Peng B, Zhu H, Klausen C, Ma L, Wang YL, Leung PCK. GnRH regulates trophoblast invasion via RUNX2-mediated MMP2/9 expression. Mol Hum Reprod 2015; 22:119-29. [PMID: 26660506 DOI: 10.1093/molehr/gav070] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 11/09/2015] [Indexed: 01/01/2023] Open
Abstract
STUDY HYPOTHESIS We hypothesized that Runt-related transcription factor 2 (RUNX2), matrix metalloproteinase (MMP)2 and MMP9 are involved in basal and gonadotrophin-releasing hormone (GnRH)-induced human extravillous trophoblast (EVT) cell invasion. STUDY FINDING Our finding indicates that GnRH-induced RUNX2 expression enhances the invasive capacity of EVT cells by modulating the expression of MMP2 and MMP9. WHAT IS KNOWN ALREADY GnRH is expressed in first-trimester placenta and exerts pro-invasive effects on EVT cells in vitro. RUNX2 regulates MMP2 and MMP9 expression and is often associated with invasive phenotypes. STUDY DESIGN, SAMPLES/MATERIALS, METHODS First-trimester human placenta (n = 9) was obtained from women undergoing elective termination of pregnancy. The localization of RUNX2, MMP2 and MMP9 in first-trimester human placenta was examined by immunohistochemistry. Primary or immortalized (HTR-8/SVneo) EVT cells were treated alone or in combination with GnRH, GnRH antagonist Antide, MAPK kinase inhibitor PD98095, phosphatidylinositol 3-kinase inhibitor LY294002, MMP2/9 inhibitor or small interfering RNAs (siRNAs) targeting RUNX2, MMP2 and/or MMP9. Protein and mRNA levels were measured by western blot and RT-PCR, respectively. Cell invasiveness was evaluated by transwell Matrigel or collagen I invasion assays. MAIN RESULTS AND THE ROLE OF CHANCE RUNX2, MMP2 and MMP9 were detected in the cell column regions of human first-trimester placental villi. GnRH treatment increased RUNX2 mRNA and protein levels in HTR-8/SVneo cells and primary EVTs, and these effects were attenuated by co-treatment with Antide, PD98095 or LY294002. Down-regulation of RUNX2 by siRNA reduced basal and GnRH-induced MMP2/9 expression and cell invasion. Moreover, pharmacological inhibition or siRNA-mediated knockdown of MMP2/9 reduced basal and GnRH-induced cell invasion. LIMITATIONS, REASONS FOR CAUTION The lack of an in vivo model is the major limitation of our in vitro study. WIDER IMPLICATIONS OF THE FINDINGS Our findings provide important insight into the functions of the GnRH - GnRH receptor system in early implantation and placentation. LARGE SCALE DATA Not applicable. STUDY FUNDING AND COMPETING INTERESTS This research was supported by Canadian Institutes of Health Research (Grant #143317) to P.C.K.L. The authors have nothing to disclose.
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Affiliation(s)
- Bo Peng
- Department of Obstetrics & Gynaecology, Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Hua Zhu
- Department of Obstetrics & Gynaecology, Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Christian Klausen
- Department of Obstetrics & Gynaecology, Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Liyang Ma
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Yan-Ling Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Peter C K Leung
- Department of Obstetrics & Gynaecology, Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada
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Schäfer-Somi S, Kowalewski M, Kanca H, Bozkurt M, Gram A, Sabitzer S, Kucukaslan I, Ay S, Aslan S. GnRH and its receptor (GnRH-R) are expressed in the canine placenta and uterus. Theriogenology 2015; 84:1482-9. [DOI: 10.1016/j.theriogenology.2015.07.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/15/2015] [Accepted: 07/17/2015] [Indexed: 11/15/2022]
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Oride A, Kanasaki H, Mijiddorj T, Sukhbaatar U, Ishihara T, Kyo S. Regulation of kisspeptin and gonadotropin-releasing hormone expression in rat placenta: study using primary cultures of rat placental cells. Reprod Biol Endocrinol 2015; 13:90. [PMID: 26268437 PMCID: PMC4533763 DOI: 10.1186/s12958-015-0083-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 07/28/2015] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Gonadotropin-releasing hormone (GnRH) and kisspeptin in the hypothalamus are thought to be crucial components of the hypothalamic-pituitary-gonadal (HPG) axis and maintain reproductive function. These neuropeptides are also expressed in the placenta, where they may contribute to placental physiology. In this study, we examined how these peptides are regulated within the placenta. METHODS We used primary cultures of placental tissue from rats of 16-18 days gestation. After stimulation with estradiol, GnRH, kisspeptin, and neurokinin B (NKB), changes in placental GnRH, kisspeptin, and human chorionic gonadotropin (hCG) mRNA expression were evaluated by real-time quantitative RT-PCR analysis. RESULTS Immunocytochemical analysis showed that rat placental cells contained cells expressing kisspeptin or GnRH. GnRH and kisspeptin mRNA expression was significantly increased in placental cells in the presence of estradiol; NKB mRNA expression was also stimulated by estradiol. Stimulation of the cells with kisspeptin failed to stimulate GnRH mRNA expression. Conversely, both GnRH itself and NKB increased GnRH mRNA expression. Kisspeptin mRNA expression was not increased by kisspeptin itself; however, GnRH and NKB significantly increased kisspeptin mRNA expression. hCG expression was increased in the presence of estradiol. In addition, kisspeptin, GnRH, and NKB could stimulate the expression of hCG mRNA in placental cells. CONCLUSIONS Our experiments using primary cultures of rat placental cells showed that GnRH, kisspeptin, and NKB expression was enhanced by estradiol, and unlike in the hypothalamus, kisspeptin did not control the expression of GnRH in placental cells. NKB might be located upstream of kisspeptin and GnRH, and these neuropeptides might be involved in the induction of hCG expression in placental cells.
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Affiliation(s)
- Aki Oride
- Department of Obstetrics and Gynecology, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan.
| | - Haruhiko Kanasaki
- Department of Obstetrics and Gynecology, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan.
| | - Tselmeg Mijiddorj
- Department of Obstetrics and Gynecology, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan.
| | - Unurjargal Sukhbaatar
- Department of Obstetrics and Gynecology, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan.
| | - Tomoko Ishihara
- Department of Obstetrics and Gynecology, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan.
| | - Satoru Kyo
- Department of Obstetrics and Gynecology, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan.
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Peng B, Zhu H, Ma L, Wang YL, Klausen C, Leung PCK. AP-1 Transcription Factors c-FOS and c-JUN Mediate GnRH-Induced Cadherin-11 Expression and Trophoblast Cell Invasion. Endocrinology 2015; 156:2269-77. [PMID: 25794160 DOI: 10.1210/en.2014-1871] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
GnRH is expressed in first-trimester human placenta and increases cell invasion in extravillous cytotrophoblasts (EVTs). Invasive phenotypes have been reported to be regulated by transcription factor activator protein 1 (AP-1) and mesenchymal cadherin-11. The aim of our study was to investigate the roles of AP-1 components (c-FOS/c-JUN) and cadherin-11 in GnRH-induced cell invasion in human EVT cells. Phosphorylated c-FOS and phosphorylated c-JUN were detected in the cell column regions of human first-trimester placental villi by immunohistochemistry. GnRH treatment increased c-FOS, c-JUN, and cadherin-11 mRNA and protein levels in immortalized EVT (HTR-8/SVneo) cells. Moreover, GnRH treatment induced c-FOS and c-JUN protein phosphorylation and nuclear accumulation. Pretreatment with antide, a GnRH antagonist, attenuated GnRH-induced cadherin-11 expression. Importantly, basal and GnRH-induced cadherin-11 expression and cell invasion were reduced by small interfering RNA-mediated knockdown of c-FOS, c-JUN, and cadherin-11 in HTR-8/SVneo cells. Our results suggest that GnRH induces the expression and phosphorylation of the AP-1 transcription factors c-FOS and c-JUN in trophoblast cells, which contributes to GnRH-induced elevation of cadherin-11 expression and cell invasion.
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Affiliation(s)
- Bo Peng
- Department of Obstetrics and Gynaecology (B.P., H.Z., C.K., P.C.K.L.), Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada V5Z 4H4; and State Key Laboratory of Reproductive Biology (L.M., Y.W.), Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
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Tan W, Huang H, Wang Y, Wong TY, Wang C, Leung LK. Bisphenol A differentially activates protein kinase C isoforms in murine placental tissue. Toxicol Appl Pharmacol 2013; 269:163-8. [DOI: 10.1016/j.taap.2013.03.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 03/20/2013] [Accepted: 03/21/2013] [Indexed: 01/21/2023]
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Gianetti E, Hall JE, Au MG, Kaiser UB, Quinton R, Stewart JA, Metzger DL, Pitteloud N, Mericq V, Merino PM, Levitsky LL, Izatt L, Lang-Muritano M, Fujimoto VY, Dluhy RG, Chase ML, Crowley WF, Plummer L, Seminara SB. When genetic load does not correlate with phenotypic spectrum: lessons from the GnRH receptor (GNRHR). J Clin Endocrinol Metab 2012; 97:E1798-807. [PMID: 22745237 PMCID: PMC3431570 DOI: 10.1210/jc.2012-1264] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
CONTEXT A broad spectrum of GnRH-deficient phenotypes has been identified in individuals with both mono- and biallelic GNRHR mutations. OBJECTIVE The objective of the study was to determine the correlation between the severity of the reproductive phenotype(s) and the number and functional severity of rare sequence variants in GNRHR. SUBJECTS Eight hundred sixty-three probands with different forms of GnRH deficiency, 46 family members and 422 controls were screened for GNRHR mutations. The 70 subjects (32 patients and 38 family members) harboring mutations were divided into four groups (G1-G4) based on the functional severity of the mutations (complete or partial loss of function) and the number of affected alleles (monoallelic or biallelic) with mutations, and these classes were mapped on their clinical phenotypes. RESULTS The prevalence of heterozygous rare sequence variants in GNRHR was significantly higher in probands vs. controls (P < 0.01). Among the G1-G3 groups (homozygous subjects with successively decreasing severity and number of mutations), the hypogonadotropic phenotype related to their genetic load. In contrast, subjects in G4, with only monoallelic mutations, demonstrated a greater diversity of clinical phenotypes. CONCLUSIONS In patients with GnRH deficiency and biallelic mutations in GNRHR, genetic burden defined by severity and dose is associated with clinical phenotype. In contrast, for patients with monoallelic GNRHR mutations this correlation does not hold. Taken together, these data indicate that as-yet-unidentified genetic and/or environmental factors may combine with singly mutated GNRHR alleles to produce reproductive phenotypes.
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Affiliation(s)
- Elena Gianetti
- Harvard Center for Reproductive Sciences and Reproductive Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, BHX 504, Boston, Massachusetts 02114, USA
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Sasaki K, Norwitz ER. Gonadotropin-releasing hormone/gonadotropin-releasing hormone receptor signaling in the placenta. Curr Opin Endocrinol Diabetes Obes 2011; 18:401-8. [PMID: 22024993 DOI: 10.1097/med.0b013e32834cd3b0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review summarizes our current understanding of the role of gonadotropin-releasing hormone (GnRH)/GnRH receptor (GnRHR) signaling at the maternal-fetal interface. RECENT FINDINGS Several isoforms of GnRH and GnRHR are described. The hypothalamic decapeptide, GnRH-I, binds to the anterior pituitary and induces the synthesis and secretion of luteinizing hormone and follicle-stimulating hormone. It is also found in extrahypothalamic sites. A second isoform, GnRH-II, acts both in the hypothalamus and other organ systems, including placenta, breast, endometrium, and ovary. Although several putative isoforms of GnRHR have been identified, it is clear that, in humans, both GnRH-I and GnRH-II signal through a single receptor, GnRHR-I. GnRH-I, GnRH-II, and GnRHR-I mRNA and protein have been identified in placenta and regulate the β-subunit of human chorionic gonadotropin production, which is essential for the maintenance of early pregnancy. They may also play a role in the autocrine/paracrine regulation of trophoblast invasion through extracellular matrix remodeling. SUMMARY GnRH-I and GnRH-II have multiple extrapituitary roles. In placenta, they bind to GnRHR-I to stimulate the production of β-subunit of human chorionic gonadotropin. They may also play a role in trophoblast invasion. A better understanding of the molecular mechanisms involved in GnRH/GnRHR signaling at the maternal-fetal interface may identify novel roles for GnRH agonists/antagonists in the prevention or treatment of hormonally mediated diseases.
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Affiliation(s)
- Kirsten Sasaki
- Department of Obstetrics & Gynecology, Tufts Medical Center, Boston, Massachusetts 02111, USA
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Escobar JC, Carr BR. The protein kinase a pathway regulates CYP17 expression and androgen production in the human placenta. J Clin Endocrinol Metab 2011; 96:2869-73. [PMID: 21733996 DOI: 10.1210/jc.2011-0542] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Our previous work demonstrated that the human placenta expresses CYP17 and is capable of de novo production of C-19 steroids; thus, it has intrinsic capacity to generate estrogens without fetal or maternal steroid precursors. OBJECTIVE Our objective was to elucidate the regulation of CYP17 expression and androgen production in the human trophoblasts. METHODS Fresh placentas and JEG-3 cells were used for all experiments. CYP17 mRNA analysis was performed via RT-PCR, and steroid products were quantified using RIA. To assess protein kinase A (PKA) pathway involvement, a pharmacological approach was used with forskolin (FSK) (10 μM), an activator, and H89 (10 μM), an inhibitor of the PKA pathway. RESULTS FSK treatment amplified CYP17 mRNA levels in both cell types when compared with basal, with levels increasing over time, peaking at 72 h, and appearing more robust in primary cells; this difference ranged from 2- to 10-fold and was statistically significant at all time points. Meanwhile, H89 reduced CYP17 levels and blunted the effect of FSK when the treatments were combined. Similarly, FSK treatment significantly increased 17α-hydroxyprogesterone concentration in both cell cultures, and H89 blunted that effect as well. CONCLUSIONS We confirm again that the human trophoblast expresses CYP17 and is able to generate estrogen precursors. We demonstrate that this process is regulated, at least in part, by the cAMP/PKA pathway.
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Affiliation(s)
- Julian C Escobar
- Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75235-9032, USA
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da Conceição AO, Takser L, Lafond J. Effect of St. John's Wort Standardized Extract and Hypericin on In Vitro Placental Calcium Transport. J Med Food 2010; 13:934-42. [DOI: 10.1089/jmf.2009.0161] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Aline Oliveira da Conceição
- Laboratory of Maternal-Fetal Physiology, Department of Biological Sciences, University of Quebec in Montreal, Montreal, Canada
- BioMedical Research Center, University of Quebec in Montreal, Montreal, Canada
- Institute of Society Health, University of Quebec in Montreal, Montreal, Canada
| | - Larissa Takser
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Julie Lafond
- Laboratory of Maternal-Fetal Physiology, Department of Biological Sciences, University of Quebec in Montreal, Montreal, Canada
- BioMedical Research Center, University of Quebec in Montreal, Montreal, Canada
- Institute of Society Health, University of Quebec in Montreal, Montreal, Canada
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Re M, Pampillo M, Savard M, Dubuc C, McArdle CA, Millar RP, Conn PM, Gobeil F, Bhattacharya M, Babwah AV. The human gonadotropin releasing hormone type I receptor is a functional intracellular GPCR expressed on the nuclear membrane. PLoS One 2010; 5:e11489. [PMID: 20628612 PMCID: PMC2900216 DOI: 10.1371/journal.pone.0011489] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 06/11/2010] [Indexed: 12/02/2022] Open
Abstract
The mammalian type I gonadotropin releasing hormone receptor (GnRH-R) is a structurally unique G protein-coupled receptor (GPCR) that lacks cytoplasmic tail sequences and displays inefficient plasma membrane expression (PME). Compared to its murine counterparts, the primate type I receptor is inefficiently folded and retained in the endoplasmic reticulum (ER) leading to a further reduction in PME. The decrease in PME and concomitant increase in intracellular localization of the mammalian GnRH-RI led us to characterize the spatial distribution of the human and mouse GnRH receptors in two human cell lines, HEK 293 and HTR-8/SVneo. In both human cell lines we found the receptors were expressed in the cytoplasm and were associated with the ER and nuclear membrane. A molecular analysis of the receptor protein sequence led us to identify a putative monopartite nuclear localization sequence (NLS) in the first intracellular loop of GnRH-RI. Surprisingly, however, neither the deletion of the NLS nor the addition of the Xenopus GnRH-R cytoplasmic tail sequences to the human receptor altered its spatial distribution. Finally, we demonstrate that GnRH treatment of nuclei isolated from HEK 293 cells expressing exogenous GnRH-RI triggers a significant increase in the acetylation and phosphorylation of histone H3, thereby revealing that the nuclear-localized receptor is functional. Based on our findings, we conclude that the mammalian GnRH-RI is an intracellular GPCR that is expressed on the nuclear membrane. This major and novel discovery causes us to reassess the signaling potential of this physiologically and clinically important receptor.
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Affiliation(s)
- Michelle Re
- The Children's Health Research Institute, London, Canada
- Lawson Health Research Institute, London, Canada
- Department of Obstetrics and Gynaecology, The University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Canada
| | - Macarena Pampillo
- The Children's Health Research Institute, London, Canada
- Lawson Health Research Institute, London, Canada
- Department of Obstetrics and Gynaecology, The University of Western Ontario, London, Canada
| | - Martin Savard
- Department of Pharmacology, Université de Sherbrooke, Sherbrooke, Canada
| | - Céléna Dubuc
- Department of Pharmacology, Université de Sherbrooke, Sherbrooke, Canada
| | - Craig A. McArdle
- Laboratories for Integrated Neuroscience and Endocrinology, Department of Clinical Sciences at South Bristol, University of Bristol, Bristol, United Kingdom
| | - Robert P. Millar
- MRC Human Reproductive Sciences Unit, The Queen's Medical Research Institute, Edinburgh, United Kingdom
| | - P. Michael Conn
- Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Fernand Gobeil
- Department of Pharmacology, Université de Sherbrooke, Sherbrooke, Canada
| | - Moshmi Bhattacharya
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Canada
| | - Andy V. Babwah
- The Children's Health Research Institute, London, Canada
- Lawson Health Research Institute, London, Canada
- Department of Obstetrics and Gynaecology, The University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Canada
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Liu J, Cao B, Li YX, Wu XQ, Wang YL. GnRH I and II up-regulate MMP-26 expression through the JNK pathway in human cytotrophoblasts. Reprod Biol Endocrinol 2010; 8:5. [PMID: 20074375 PMCID: PMC2819245 DOI: 10.1186/1477-7827-8-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 01/15/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Matrix metalloproteinase-26 (MMP-26), one of the main mediators of extracellular matrix (ECM) degradation, has been shown to exist in trophoblasts of human placenta and to play a role in trophoblast cell invasion. However, little is known about the regulation of MMP-26 expression in human trophoblasts. Recently, gonadotropin-releasing hormone I (GnRH I) and GnRH II have been shown to regulate the expression of MMP-2, MMP-9/tissue inhibitor of metalloproteinases 1 (TIMP-1), and urokinase plasminogen activator (uPA)/plasminogen activator inhibitor (PAI) in human trophoblasts, suggesting that these two hormones may work as paracrine and/or autocrine regulators in modulating the activities of various protease systems at the feto-maternal interface. In this study, we determined the regulatory effects of GnRH I and GnRH II on the expression of MMP-26 in human immortalized cytotrophoblast-like cell line, B6Tert-1. METHODS Real-time PCR was used to quantify mRNA levels of MMP-26 in human trophoblast-like cell line, B6Tert-1 and primary cultured cytotrophoblasts. Western blotting was used to characterize the expression of MMP-26 and the phosphorylation of c-Jun NH2-terminal kinase (JNK) and extracellular signal-regulated kinase 1/2 (ERK1/2) in B6Tert-1 cells after treatment with GnRH I and GnRH II. RESULTS We found that GnRH I increased MMP-26 expression in B6Tert-1 cells after 12 h of treatment at both the mRNA and protein level, while GnRH II increased MMP-26 expression beginning at 3 h of treatment. Treatment of GnRH I at 1 nM resulted in maximal increase of MMP-26 mRNA and protein levels, whereas GnRH II treatment at a concentration of 100 nM was required to induce maximal increase in MMP-26 expression. In addition, we demonstrated that the activation of JNK, but not ERK1/2, was required for GnRH I and II-stimulated MMP-26 production in B6Tert-1 cells and primary cytotrophoblasts. CONCLUSIONS These novel findings indicated that GnRH I and II could up-regulate MMP-26 expression through the JNK signaling pathway in human trophoblast-like/trophoblast cells.
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Affiliation(s)
- Jing Liu
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 10029, PR China
| | - Bin Cao
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Yu-xia Li
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Xiao-qiu Wu
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Yan-ling Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
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Magnarelli G, Souza MS, D'Angelo AMPD. Heptachlor ando-p′DDT effects on protein kinase activities associated with human placenta particulate fractions. J Biochem Mol Toxicol 2009; 23:185-92. [DOI: 10.1002/jbt.20277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Liu J, Maccalman CD, Wang YL, Leung PCK. Promotion of human trophoblasts invasion by gonadotropin-releasing hormone (GnRH) I and GnRH II via distinct signaling pathways. Mol Endocrinol 2009; 23:1014-21. [PMID: 19372239 DOI: 10.1210/me.2008-0451] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The potential roles of GnRH I and GnRH II have been assigned in promoting the invasive capacity of human trophoblasts by regulating matrix metalloproteinases-2 and -9, type I tissue inhibitor of matrix metalloproteinase, and urokinase plasminogen activator/plasminogen activator inhibitor protease systems during human placentation, and GnRH II has been shown to be more potent than GnRH I. However, the mechanisms for the differential effects of these two hormones remain unclear. In this study, we examined the invasion-promoting effects and the signaling pathways of GnRH I and GnRH II in human trophoblasts. The data revealed that both GnRH I and GnRH II were key autocrine and/or paracrine regulators in facilitating trophoblast invasion. The GnRH receptor antagonist (Antide) and specific small interfering RNA for GnRH receptor inhibited the regulatory effects of GnRH I, but not GnRH II, on trophoblast invasion. Both GnRH I and II activated protein kinase C, ERK1/2, and c-Jun N-terminal kinase to mediate their effects on trophoblast invasion, whereas only GnRH II elicited invasion-promoting action through transactivating the tyrosine kinase activity of epidermal growth factor receptor in trophoblasts. Our observations elucidate a ligand-dependent selective cross-communication between GnRH receptor and epidermal growth factor receptor signaling systems in human trophoblastic cell, and this would further our understanding on the differentially biological significance of these two forms of GnRH in extrapituitary tissues.
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Affiliation(s)
- Jing Liu
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China
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Tian G, Singh U, Yu Y, Ellsworth BS, Hemberger M, Geyer R, Stewart MD, Behringer RR, Fundele R. Expression and function of the LIM homeobox containing genes Lhx3 and Lhx4 in the mouse placenta. Dev Dyn 2008; 237:1517-25. [PMID: 18425848 DOI: 10.1002/dvdy.21546] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The LIM homeobox containing genes of the LIM-3 group, Lhx3 and Lhx4, are critical for normal development. Both genes are involved in the formation of the pituitary and the motoneuron system and loss of either gene causes perinatal lethality. Previous studies had shown that Lhx3 is overexpressed in hyperplastic placentas of mouse interspecies hybrids. To determine the role of LHX3 in the mouse placenta, we performed expression and function analyses. Our results show that Lhx3 exhibits specific spatial and temporal expression in the mouse placenta. However, deletion of Lhx3 does not produce a placental phenotype. To test whether this is due to functional substitution by Lhx4, we performed a phenotype analysis of Lhx3-/-; Lhx4-/- double-mutant placentas. A subset of Lhx3-/-; Lhx4-/- placentas exhibited abnormal structure of the labyrinth. However, absence of both LIM-3 genes did not interfere with placental transport nor consistently with expression of target genes such as Gnrhr. Thus, LHX3 and LHX4 appear to be dispensable for placental development and function.
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Affiliation(s)
- Geng Tian
- Department of Animal Genetics and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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Cheng CK, Leung PCK. Molecular biology of gonadotropin-releasing hormone (GnRH)-I, GnRH-II, and their receptors in humans. Endocr Rev 2005; 26:283-306. [PMID: 15561800 DOI: 10.1210/er.2003-0039] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In human beings, two forms of GnRH, termed GnRH-I and GnRH-II, encoded by separate genes have been identified. Although these hormones share comparable cDNA and genomic structures, their tissue distribution and regulation of gene expression are significantly dissimilar. The actions of GnRH are mediated by the GnRH receptor, which belongs to a member of the rhodopsin-like G protein-coupled receptor superfamily. However, to date, only one conventional GnRH receptor subtype (type I GnRH receptor) uniquely lacking a carboxyl-terminal tail has been found in the human body. Studies on the transcriptional regulation of the human GnRH receptor gene have indicated that tissue-specific gene expression is mediated by differential promoter usage in various cell types. Functionally, there is growing evidence showing that both GnRH-I and GnRH-II are potentially important autocrine and/or paracrine regulators in some extrapituitary compartments. Recent cloning of a second GnRH receptor subtype (type II GnRH receptor) in nonhuman primates revealed that it is structurally and functionally distinct from the mammalian type I receptor. However, the human type II receptor gene homolog carries a frameshift and a premature stop codon, suggesting that a full-length type II receptor does not exist in humans.
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Affiliation(s)
- Chi Keung Cheng
- Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada V6H 3V5
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Hoo RLC, Ngan ESW, Leung PCK, Chow BKC. Two Inr elements are important for mediating the activity of the proximal promoter of the human gonadotropin-releasing hormone receptor gene. Endocrinology 2003; 144:518-27. [PMID: 12538612 DOI: 10.1210/en.2002-220591] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Differential usage of several transcription start sites in the human GnRH receptor gene was evident in human brain and pituitary. To locate the promoter responsible for a cluster of the 3' CAP sites from -635 to -578 (relative to ATG) found in the pituitary, a proximal promoter element was identified at -677/-558 by 5' and 3' deletion mutant analysis. The promoter element drove a 13.1 +/- 0.6-fold increase in reporter gene activity in an orientation-dependent manner in the mouse gonadotrope-derived alphaT3-1 cells. Within the core promoter element, two functional AT-rich Inr motifs, interacting with the same protein factor with different affinities, were identified. By Southwestern blot analysis and competitive gel mobility shift assays, multiple nuclear factors (36-150 kDa) were found to interact specifically with the core promoter element. Interestingly, these nuclear proteins also interacted with a previously identified distal promoter of the human GnRH receptor gene. Taken together, our studies suggested that these two promoters share common protein factors to regulate transcription initiations at two different regions. Additional mechanisms are needed to modulate the efficiencies of individual promoters for developmental and/or tissue-specific regulations.
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Affiliation(s)
- Ruby L C Hoo
- Department of Zoology, the University of Hong Kong, Hong Kong, Hong Kong
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Abstract
Pulsatile gonadotropin-releasing hormone (GnRH) stimulates the pituitary secretion of both luteinising hormone (LH) and follicle-stimulating hormone (FSH) and thus controls the hormonal and reproductive function of the gonads. Blockade of GnRH effects may be wanted for a variety of reasons-eg, to prevent untimely luteinisation during assisted reproduction or in the treatment of sex-hormone-dependent disorders. Selective blockade of LH/FSH secretion and subsequent chemical castration have previously been achieved by desensitising the pituitary to continuously administered GnRH or by giving long-acting GnRH agonists. Only recently have GnRH-receptor antagonists, that immediately block GnRH's effects, been developed for clinical use with acceptable pharmacokinetic, safety, and commercial profiles. In assisted reproduction, these compounds seem to be as effective as established therapy but with shorter treatment times, less use of gonadotropic hormones, improved patient acceptance, and fewer follicles and oocytes. All current indications for GnRH-agonist desensitisation may prove to be indications for a GnRH antagonist, including endometriosis, leiomyoma, and breast cancer in women, benign prostatic hypertrophy and prostatic carcinoma in men, and central precocious puberty in children. However, the best clinical evidence so far has been in assisted reproduction and prostate cancer.
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Affiliation(s)
- J A Huirne
- Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, PO Box 7057, 1007MB, Amsterdam, Netherlands
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Cheng KW, Leung PCK. The expression, regulation and signal transduction pathways of the mammalian gonadotropin-releasing hormone receptor. Can J Physiol Pharmacol 2000. [DOI: 10.1139/y00-096] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Normal mammalian sexual maturation and reproductive functions require the integration and precise coordination of hormones at the hypothalamic, pituitary, and gonadal levels. Hypothalamic gonadotropin-releasing hormone (GnRH) is a key regulator in this system; after binding to its receptor (GnRHR), it stimulates de novo synthesis and release of gonadotropins in anterior pituitary gonadotropes. Since the isolation of the GnRHR cDNA, the expression of GnRHR mRNA has been detected not only in the pituitary, but also in extrapituitary tissues, including the ovary and placenta. It has been shown that change in GnRHR mRNA is one of the mechanisms for regulating the expression of the GnRHR. To help understand the molecular mechanism(s) involved in transcriptional regulation of the GnRHR gene, the 5' flanking region of the GnRHR gene has recently been isolated. Initial characterization studies have identified several DNA regions in the GnRHR 5' flanking region which are responsible for both basal expression and GnRH-mediated homologous regulation of this gene in pituitary cells. The mammalian GnRHR lacks a C-terminus and possesses a relatively short third intracellular loop; both features are important in desensitization of many others G-protein coupled receptors (GPCRs), Homologous desensitization of GnRHR has been shown to be regulated by various serine-threonine protein kinases including protein kinase A (PKA) and protein kinase C (PKC), as well as by G-protein coupled receptor kinases (GRKs). Furthermore, GnRHR was demonstrated to couple with multiple G proteins (Gq/11, Gs, and Gi), and to activate cascades that involved the PKC, PKA, and mitogen-activator protein kinases. These results suggest the diversity of GnRHR-G protein coupling and signal transduction systems. The identification of second form of GnRH (GnRH-II) in mammals adds to the complexity of the GnRH-GnRHR system. This review summaries our recent progress in understanding the regulation of GnRHR gene expression and the GnRHR signal transduction pathways.Key words: gonadotropin-releasing hormone receptor, transcriptional regulation, desensitization, signal transduction.
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