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Wijeweera A, Haj M, Feldman A, Pnueli L, Luo Z, Melamed P. Gonadotropin gene transcription is activated by menin-mediated effects on the chromatin. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:328-41. [DOI: 10.1016/j.bbagrm.2015.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 12/08/2014] [Accepted: 01/03/2015] [Indexed: 12/12/2022]
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Jin JM, Yang WX. Molecular regulation of hypothalamus-pituitary-gonads axis in males. Gene 2014; 551:15-25. [PMID: 25168889 DOI: 10.1016/j.gene.2014.08.048] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 07/24/2014] [Accepted: 08/24/2014] [Indexed: 10/24/2022]
Abstract
The hypothalamic-pituitary-gonadal axis (HPG) plays vital roles in reproduction and steroid hormone production in both sexes. The focus of this review is upon gene structures, receptor structures and the signaling pathways of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The hormones' functions in reproduction as well as consequences resulting from mutations are also summarized. Specific characteristics of hormones such as the pulsatile secretions of GnRH are also covered. The different regulators of the HPG axis are introduced including kisspeptin, activin, inhibin, follistatin, androgens and estrogen. This review includes not only their basic information, but also their unique function in the HPG axis. Here we view the HPG axis as a whole, so relations between ligands and receptors are well described crossing different levels of the HPG axis. Hormone interactions and transformations are also considered. The major information of this article is depicted in three figures summarizing the current discoveries on the HPG axis. This article systematically introduces the basic knowledge of the HPG axis and provides information of the current advances relating to reproductive hormones.
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Affiliation(s)
- Jia-Min Jin
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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Perrett RM, McArdle CA. Molecular mechanisms of gonadotropin-releasing hormone signaling: integrating cyclic nucleotides into the network. Front Endocrinol (Lausanne) 2013; 4:180. [PMID: 24312080 PMCID: PMC3834291 DOI: 10.3389/fendo.2013.00180] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 11/06/2013] [Indexed: 01/21/2023] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is the primary regulator of mammalian reproductive function in both males and females. It acts via G-protein coupled receptors on gonadotropes to stimulate synthesis and secretion of the gonadotropin hormones luteinizing hormone and follicle-stimulating hormone. These receptors couple primarily via G-proteins of the Gq/ll family, driving activation of phospholipases C and mediating GnRH effects on gonadotropin synthesis and secretion. There is also good evidence that GnRH causes activation of other heterotrimeric G-proteins (Gs and Gi) with consequent effects on cyclic AMP production, as well as for effects on the soluble and particulate guanylyl cyclases that generate cGMP. Here we provide an overview of these pathways. We emphasize mechanisms underpinning pulsatile hormone signaling and the possible interplay of GnRH and autocrine or paracrine regulatory mechanisms in control of cyclic nucleotide signaling.
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Affiliation(s)
- Rebecca M. Perrett
- Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Craig A. McArdle
- Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, Bristol, UK
- *Correspondence: Craig A. McArdle, Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, 1 Whitson Street, Bristol BS1 3NY, UK e-mail:
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Melamed P, Savulescu D, Lim S, Wijeweera A, Luo Z, Luo M, Pnueli L. Gonadotrophin-releasing hormone signalling downstream of calmodulin. J Neuroendocrinol 2012; 24:1463-75. [PMID: 22775470 DOI: 10.1111/j.1365-2826.2012.02359.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/24/2012] [Accepted: 07/03/2012] [Indexed: 01/26/2023]
Abstract
Gonadotrophin-releasing hormone (GnRH) regulates reproduction via binding a G-protein coupled receptor on the surface of the gonadotroph, through which it transmits signals, mostly via the mitogen-activated protein (MAPK) cascade, to increase synthesis of the gonadotrophin hormones: luteinising hormone (LH) and follicle-stimulating hormone (FSH). Activation of the MAPK cascade requires an elevation in cytosolic Ca(2+) levels, which is a result of both calcium influx and mobilisation from intracellular stores. However, Ca(2+) also transmits signals via an MAPK-independent pathway, through binding calmodulin (CaM), which is then able to bind a number of proteins to impart diverse downstream effects. Although the ability of GnRH to activate CaM was recognised over 20 years ago, only recently have some of the downstream effects been elucidated. GnRH was shown to activate the CaM-dependent phosphatase, calcineurin, which targets gonadotrophin gene expression both directly and indirectly via transcription factors such as nuclear factor of activated T-cells and Nur77, the Transducer of Regulated CREB (TORC) co-activators and also the prolyl isomerase, Pin1. Gonadotrophin gene expression is also regulated by GnRH-induced CaM-dependent kinases (CaMKs); CaMKI is able to derepress the histone deacetylase-inhibition of β-subunit gene expression, whereas CaMKII appears to be essential for the GnRH-activation of all three subunit genes. Asides from activating gonadotrophin gene expression, GnRH also exerts additional effects on gonadotroph function, some of which clearly occur via CaM, including the proliferation of immature gonadotrophs, which is dependent on calcineurin. In this review, we summarise these pathways, and discuss the additional functions that have been proposed for CaM with respect to modifying GnRH-induced signalling pathways via the regulation of the small GTP-binding protein, Gem, and/or the regulator of G-protein signalling protein 2.
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Affiliation(s)
- P Melamed
- Technion-Israel Institute of Technology, Haifa, Israel.
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Yu H, Li Z, Ghosh D, Lim TK, He Y, Lin Q. α-Actinin4 nuclear translocation mediates gonadotropin-releasing hormone stimulation of follicle-stimulating hormone β-subunit gene transcription in LβT2 cells. FEBS Lett 2012; 586:1466-71. [PMID: 22673512 DOI: 10.1016/j.febslet.2012.03.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 02/17/2012] [Accepted: 03/30/2012] [Indexed: 11/19/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) regulates the synthesis and secretion of follicle-stimulating hormone (FSH) by stimulating the transcription of Fshβ gene. Our iTRAQ quantitative proteomics result showed that the abundance of α-actinin4 (ACTN4) increased in the nuclei of LβT2 cells upon GnRH induction. Using RNA interference, reverse transcription and real-time PCR, luciferase and transient transfection assays, we proved that ACTN4 is involved in the regulation of mouse Fshβ gene (mFshβ) transcription and its C-terminal calmodulin (CaM)-like domain is crucial for this process. Our study suggests that ACTN4 nuclear translocation mediates GnRH stimulation of mFshβ gene transcription.
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Affiliation(s)
- Han Yu
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
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Lau MT, Lin SW, Ge W. Identification of Smad Response Elements in the Promoter of Goldfish FSHβ Gene and Evidence for Their Mediation of Activin and GnRH Stimulation of FSHβ Expression. Front Endocrinol (Lausanne) 2012; 3:47. [PMID: 22645522 PMCID: PMC3355844 DOI: 10.3389/fendo.2012.00047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 03/11/2012] [Indexed: 12/28/2022] Open
Abstract
As an essential hormone regulating gonads in vertebrates, the biosynthesis and secretion of follicle-stimulating hormone (FSH) is controlled by a variety of endocrine and paracrine factors in both mammalian and non-mammalian vertebrates. Activin was initially discovered in the ovary for its specific stimulation of FSH secretion by the pituitary cells. Our earlier studies in fish have shown that activin stimulates FSHβ but suppresses LHβ expression in both the goldfish and zebrafish. Further experiments showed that the regulation of FSHβ in fish occurred at the promoter level involving Smads, in particular Smad3. To further understand the mechanisms by which activin/Smad regulates FSHβ transcription, the present study was undertaken to analyze the promoter of goldfish FSHβ gene (fshb) with the aim to identify potential cis-regulatory elements responsible for activin/Smad stimulation. Both serial deletion and site-directed mutagenesis were used, and the promoter activity was tested in the LβT-2 cells, a murine gonadotroph cell line. The reporter constructs of goldfish FSHβ promoter-SEAP (secreted alkaline phosphatase) were co-transfected with an expression plasmid for Smads (2 or 3) followed by measurement of SEAP activity in the medium. Two putative Smad responsive elements were identified in the promoter at distal and proximal regions, respectively. The distal site contained a consensus Smad binding element (AGAC, -1675/-1672) whereas the proximal site (GACCTTGA, -212/-205) was identical to an SF-1 binding site reported in humans, which was preceded by a sequence (AACACTGA) highly conserved between fish and mammals. The proximal site also seemed to be involved in mediating stimulation of FSHβ expression by gonadotropin-releasing hormone and its potential interaction with activin. In conclusion, we have identified two potential cis-regulatory elements in the promoter of goldfish FSHβ that are responsible for activin-induced expression of the gene. Since activin stimulation of FSHβ expression is functionally conserved in fish and mammals, our findings contribute to the understanding of the fundamental mechanisms of this regulation across vertebrates.
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Affiliation(s)
- Man-Tat Lau
- School of Life Sciences and Centre for Cell and Developmental Biology, The Chinese University of Hong KongHong Kong, China
| | - Sze-Wah Lin
- School of Life Sciences and Centre for Cell and Developmental Biology, The Chinese University of Hong KongHong Kong, China
| | - Wei Ge
- School of Life Sciences and Centre for Cell and Developmental Biology, The Chinese University of Hong KongHong Kong, China
- *Correspondence: Wei Ge, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China. e-mail:
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Calcineurin mediates the gonadotropin-releasing hormone effect on expression of both subunits of the follicle-stimulating hormone through distinct mechanisms. Mol Cell Biol 2011; 31:5023-36. [PMID: 21986493 DOI: 10.1128/mcb.06083-11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Gonadotropin-releasing hormone (GnRH) regulates the expression of all three gonadotropin genes, encoding the common α subunit (αGSU) and hormone-specific β subunits, through the activation of several signal transduction pathways. We have shown that GnRH also upregulates calcineurin, and we hypothesized that calcineurin mediates the effects of GnRH on the transcription of the αGSU and follicle-stimulating hormone β (FSHβ) genes through two of its targets: nuclear factor of activated T cells (NFAT) and CREB-regulated transcription coactivator (TORC). We show that calcineurin is essential for GnRH-induced expression of both genes but that NFAT and TORC1 play quite distinct roles in activating each gene. GnRH induces calcineurin-dependent nuclear import of NFAT3, which activates the αGSU promoter, while TORC1 also mediates GnRH activation of this promoter, but not through CREB. GnRH initially stimulates the degradation of TORC1 but protects the N terminus of the newly synthesized protein to enhance its activity. Calcineurin induces Nur77 expression, likely via NFAT3, and Nur77 interacts synergistically with TORC1 and CREB to increase FSHβ promoter activity. Although TORC plays a role in the basal activity of the FSHβ promoter, it does not interact with phosphorylated CREB and probably does not play a major role in direct GnRH signaling to this gene. TORC may be part of an alternatively regulated pathway, possibly involving cross talk with other stimulatory hormones.
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Makanji Y, Harrison CA, Robertson DM. Feedback Regulation by Inhibins A and B of the Pituitary Secretion of Follicle-Stimulating Hormone. VITAMINS AND HORMONES 2011; 85:299-321. [DOI: 10.1016/b978-0-12-385961-7.00014-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Bliss SP, Navratil AM, Xie J, Roberson MS. GnRH signaling, the gonadotrope and endocrine control of fertility. Front Neuroendocrinol 2010; 31:322-40. [PMID: 20451543 PMCID: PMC2923852 DOI: 10.1016/j.yfrne.2010.04.002] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2010] [Revised: 04/26/2010] [Accepted: 04/30/2010] [Indexed: 11/28/2022]
Abstract
Mammalian reproductive cycles are controlled by an intricate interplay between the hypothalamus, pituitary and gonads. Central to the function of this axis is the ability of the pituitary gonadotrope to appropriately respond to stimulation by gonadotropin-releasing hormone (GnRH). This review focuses on the role of cell signaling and in particular, mitogen-activated protein kinase (MAPK) activities regulated by GnRH that are necessary for normal fertility. Recently, new mouse models making use of conditional gene deletion have shed new light on the relationships between GnRH signaling and fertility in both male and female mice. Within the reproductive axis, GnRH signaling is initiated through discrete membrane compartments in which the receptor resides leading to the activation of the extracellular signal-regulated kinases (ERKs 1/2). As defined by gonadotrope-derived cellular models, the ERKs appear to play a central role in the regulation of a cohort of immediate early genes that regulate the expression of late genes that, in part, define the differentiated character of the gonadotrope. Recent data would suggest that in vivo, conditional, pituitary-specific disruption of ERK signaling by GnRH leads to a gender-specific perturbation of fertility. Double ERK knockout in the anterior pituitary leads to female infertility due to LH biosynthesis deficiency and a failure in ovulation. In contrast, male mice are modestly LH deficient; however, this does not have an appreciable impact on fertility.
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Affiliation(s)
- Stuart P Bliss
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, United States
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Luo Z, Wijeweera A, Oh Y, Liou YC, Melamed P. Pin1 facilitates the phosphorylation-dependent ubiquitination of SF-1 to regulate gonadotropin beta-subunit gene transcription. Mol Cell Biol 2010; 30:745-63. [PMID: 19995909 PMCID: PMC2812243 DOI: 10.1128/mcb.00807-09] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 09/10/2009] [Accepted: 11/23/2009] [Indexed: 11/20/2022] Open
Abstract
Pin1 is a peptidyl-prolyl cis-trans isomerase which catalyzes the isomerization of phosphorylated Ser/Thr-Pro peptide bonds. Pin1 knockout mice have marked abnormalities in their reproductive development and function. However, the molecular mechanisms underlying their reproductive defects are poorly understood. Herein, we demonstrate that Pin1 is required for both basal and GnRH-induced gonadotropin beta-subunit gene transcription, through interactions with the transcription factors SF-1, Pitx1, and Egr-1. Pin1 activates transcription of the gonadotropin beta-subunit genes synergistically with these transcription factors, either by modulating their stability or by increasing their protein-protein interactions. Notably, we provide evidence that Pin1 is required for the Ser203 phosphorylation-dependent ubiquitination of SF-1, which facilitates SF-1-Pitx1 interactions and therefore results in an enhancement of SF-1 transcriptional activity. Furthermore, we demonstrate that in gonadotrope cells, sufficient levels of activated Pin1 are maintained through transcriptional and posttranslational regulation by GnRH-induced signaling cascades. Our results suggest that Pin1 functions as a novel player in GnRH-induced signal pathways and is involved in gonadotropin beta-subunit gene transcription by modulating the activity of various specific transcription factors.
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Affiliation(s)
- Zhuojuan Luo
- Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543, Singapore, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Andrea Wijeweera
- Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543, Singapore, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Yingzi Oh
- Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543, Singapore, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Yih-Cherng Liou
- Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543, Singapore, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Philippa Melamed
- Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543, Singapore, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 32000, Israel
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