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Ongaro L, Schang G, Zhou Z, Kumar TR, Treier M, Deng CX, Boehm U, Bernard DJ. Human Follicle-Stimulating Hormone ß Subunit Expression Depends on FOXL2 and SMAD4. Endocrinology 2020; 161:5805118. [PMID: 32191302 PMCID: PMC7182064 DOI: 10.1210/endocr/bqaa045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/09/2020] [Indexed: 12/11/2022]
Abstract
Follicle-stimulating hormone (FSH), an essential regulator of mammalian fertility, is synthesized by pituitary gonadotrope cells in response to activins. In mice, activins signal via SMAD3, SMAD4, and FOXL2 to regulate transcription of the FSHβ subunit (Fshb) gene. Gonadotrope-specific deletion of Foxl2, alone or in combination with Smad4, renders mice FSH-deficient. Whether human FSHB expression is similarly regulated is not known. Here, we used a combination of transgenic and conditional knockout mouse strains to assess the roles of activins, FOXL2, and SMAD4 in regulation of the human FSHB gene. First, we cultured pituitaries from mice harboring a human FSHB transgene (hFSHB mice) and measured both murine Fshb and human FSHB messenger ribonucleic acid (mRNA) expression in response to exogenous activins or two antagonists of endogenous activin-like signaling (follistatin-288 and SB431542). Both murine Fshb and human FSHB expression were stimulated by activins and reduced by the inhibitors. Next, we analyzed human FSHB expression in hFSHB mice carrying floxed Foxl2 and Smad4 alleles. Cre-mediated ablation of FOXL2 and SMAD4 strongly reduced basal and activin-stimulated murine Fshb and human FSHB expression in cultured pituitaries. Finally, the hFSHB transgene was previously shown to rescue FSH production and fertility in Fshb knockout mice. However, gonadotrope-specific Foxl2/Smad4 knockout females carrying the hFSHB transgene have significantly reduced murine Fshb and human FSHB pituitary mRNA levels and are hypogonadal. Collectively, these data suggest that similar to Fshb regulation in mice, FOXL2 and SMAD4 play essential roles in human FSHB expression.
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Affiliation(s)
- Luisina Ongaro
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Gauthier Schang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Ziyue Zhou
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - T Rajendra Kumar
- Department of Obstetrics and Gynecology, University of Colorado Denver-Anschutz Medical Campus, Aurora, CO, US
| | - Mathias Treier
- Max-Delbrück Center for Molecular Medicine (MDC), Genetics of Metabolic and Reproductive Disorders, Berlin, Germany
| | - Chu-Xia Deng
- Faculty of Health Sciences, University of Macau, China
| | - Ulrich Boehm
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), Saarland University School of Medicine, Homburg, Germany
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
- Correspondence: Daniel J. Bernard Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada. E-mail:
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McDonald R, Sadler C, Kumar TR. Gain-of-Function Genetic Models to Study FSH Action. Front Endocrinol (Lausanne) 2019; 10:28. [PMID: 30792692 PMCID: PMC6374295 DOI: 10.3389/fendo.2019.00028] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/15/2019] [Indexed: 12/15/2022] Open
Abstract
Follicle-stimulating hormone (FSH) is a pituitary-derived gonadotropin that plays key roles in male and female reproduction. The physiology and biochemistry of FSH have been extensively studied for many years. Beginning in the early 1990s, coincident with advances in the then emerging transgenic animal technology, and continuing till today, several gain-of-function (GOF) models have been developed to understand FSH homeostasis in a physiological context. Our group and others have generated a number of FSH ligand and receptor GOF mouse models. An FSH GOF model when combined with Fshb null mice provides a powerful genetic rescue platform. In this chapter, we discuss different GOF models for FSH synthesis, secretion and action and describe additional novel genetic models that could be developed in the future to further refine the existing models.
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Affiliation(s)
- Rosemary McDonald
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, IL, United States
- Integrated Physiology Graduate Program, University of Colorado Anschutz Medical CampusAurora, IL, United States
| | - Carolyn Sadler
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, IL, United States
| | - T. Rajendra Kumar
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, IL, United States
- Integrated Physiology Graduate Program, University of Colorado Anschutz Medical CampusAurora, IL, United States
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical CampusAurora, IL, United States
- *Correspondence: T. Rajendra Kumar
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Gilbert SB, Roof AK, Rajendra Kumar T. Mouse models for the analysis of gonadotropin secretion and action. Best Pract Res Clin Endocrinol Metab 2018; 32:219-239. [PMID: 29779578 PMCID: PMC5973545 DOI: 10.1016/j.beem.2018.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Gonadotropins are pituitary gonadotrope-derived glycoprotein hormones. They act by binding to G-protein coupled receptors on gonads. Gonadotropins play critical roles in reproduction by regulating both gametogenesis and steroidogenesis. Although biochemical and physiological studies provided a wealth of knowledge, gene manipulation techniques using novel mouse models gave new insights into gonadotropin synthesis, secretion and action. Both gain of function and loss of function mouse models for understanding gonadotropin action in a whole animal context have already been generated. Moreover, recent studies on gonadotropin actions in non-gonadal tissues challenged the central dogma of classical gonadotropin actions in gonads and revealed new signaling pathways in these non-gonadal tissues. In this Chapter, we have discussed our current understanding of gonadotropin synthesis, secretion and action using a variety of genetically engineered mouse models.
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Affiliation(s)
- Sara Babcock Gilbert
- Division of Reproductive Endocrinology and Infertility, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA; Division of Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA; Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Allyson K Roof
- Division of Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA; Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - T Rajendra Kumar
- Division of Reproductive Endocrinology and Infertility, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA; Division of Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA; Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Das N, Kumar TR. Molecular regulation of follicle-stimulating hormone synthesis, secretion and action. J Mol Endocrinol 2018; 60:R131-R155. [PMID: 29437880 PMCID: PMC5851872 DOI: 10.1530/jme-17-0308] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 02/07/2018] [Indexed: 12/11/2022]
Abstract
Follicle-stimulating hormone (FSH) plays fundamental roles in male and female fertility. FSH is a heterodimeric glycoprotein expressed by gonadotrophs in the anterior pituitary. The hormone-specific FSHβ-subunit is non-covalently associated with the common α-subunit that is also present in the luteinizing hormone (LH), another gonadotrophic hormone secreted by gonadotrophs and thyroid-stimulating hormone (TSH) secreted by thyrotrophs. Several decades of research led to the purification, structural characterization and physiological regulation of FSH in a variety of species including humans. With the advent of molecular tools, availability of immortalized gonadotroph cell lines and genetically modified mouse models, our knowledge on molecular mechanisms of FSH regulation has tremendously expanded. Several key players that regulate FSH synthesis, sorting, secretion and action in gonads and extragonadal tissues have been identified in a physiological setting. Novel post-transcriptional and post-translational regulatory mechanisms have also been identified that provide additional layers of regulation mediating FSH homeostasis. Recombinant human FSH analogs hold promise for a variety of clinical applications, whereas blocking antibodies against FSH may prove efficacious for preventing age-dependent bone loss and adiposity. It is anticipated that several exciting new discoveries uncovering all aspects of FSH biology will soon be forthcoming.
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Affiliation(s)
- Nandana Das
- Division of Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, U.S.A
| | - T. Rajendra Kumar
- Division of Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, U.S.A
- Division of Reproductive Endocrinology and Infertility, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, U.S.A
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, U.S.A
- Author for Correspondence: T. Rajendra Kumar, PhD, Edgar L. and Patricia M. Makowski Professor, Associate Vice-Chair of Research, Department of Obstetrics & Gynecology, University of Colorado Anschutz Medical Campus, Mail Stop 8613, Research Complex 2, Room # 15-3000B, 12700 E. 19th Avenue, Aurora, CO 80045, USA, Tel: 303-724-8689,
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The syndrome of central hypothyroidism and macroorchidism: IGSF1 controls TRHR and FSHB expression by differential modulation of pituitary TGFβ and Activin pathways. Sci Rep 2017; 7:42937. [PMID: 28262687 PMCID: PMC5338029 DOI: 10.1038/srep42937] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 01/18/2017] [Indexed: 12/22/2022] Open
Abstract
IGSF1 (Immunoglobulin Superfamily 1) gene defects cause central hypothyroidism and macroorchidism. However, the pathogenic mechanisms of the disease remain unclear. Based on a patient with a full deletion of IGSF1 clinically followed from neonate to adulthood, we investigated a common pituitary origin for hypothyroidism and macroorchidism, and the role of IGSF1 as regulator of pituitary hormone secretion. The patient showed congenital central hypothyroidism with reduced TSH biopotency, over-secretion of FSH at neonatal minipuberty and macroorchidism from 3 years of age. His markedly elevated inhibin B was unable to inhibit FSH secretion, indicating a status of pituitary inhibin B resistance. We show here that IGSF1 is expressed both in thyrotropes and gonadotropes of the pituitary and in Leydig and germ cells in the testes, but at very low levels in Sertoli cells. Furthermore, IGSF1 stimulates transcription of the thyrotropin-releasing hormone receptor (TRHR) by negative modulation of the TGFβ1-Smad signaling pathway, and enhances the synthesis and biopotency of TSH, the hormone secreted by thyrotropes. By contrast, IGSF1 strongly down-regulates the activin-Smad pathway, leading to reduced expression of FSHB, the hormone secreted by gonadotropes. In conclusion, two relevant molecular mechanisms linked to central hypothyroidism and macroorchidism in IGSF1 deficiency are identified, revealing IGSF1 as an important regulator of TGFβ/Activin pathways in the pituitary.
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Mouse Models for the Study of Synthesis, Secretion, and Action of Pituitary Gonadotropins. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 143:49-84. [PMID: 27697204 DOI: 10.1016/bs.pmbts.2016.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Gonadotropins play fundamental roles in reproduction. More than 30years ago, Cga transgenic mice were generated, and more than 20years ago, the phenotypes of Cga null mice were reported. Since then, numerous mouse strains have been generated and characterized to address several questions in reproductive biology involving gonadotropin synthesis, secretion, and action. More recently, extragonadal expression, and in some cases, functions of gonadotropins in nongonadal tissues have been identified. Several genomic and proteomic approaches including novel mouse genome editing tools are available now. It is anticipated that these and other emerging technologies will be useful to build an integrated network of gonadotropin signaling pathways in various tissues. Undoubtedly, research on gonadotropins will continue to provide new knowledge and allow us transcend from benchside to the bedside.
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Wang H, Hastings R, Miller WL, Kumar TR. Fshb-iCre mice are efficient and specific Cre deleters for the gonadotrope lineage. Mol Cell Endocrinol 2016; 419:124-38. [PMID: 26472536 PMCID: PMC4684453 DOI: 10.1016/j.mce.2015.10.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 10/06/2015] [Accepted: 10/07/2015] [Indexed: 02/06/2023]
Abstract
Genetic analysis of development and function of the gonadotrope cell lineage within mouse anterior pituitary has been greatly facilitated by at least three currently available Cre strains in which Cre was either knocked into the Gnrhr locus or expressed as a transgene from Cga and Lhb promoters. However, in each case there are some limitations including CRE expression in thyrotropes within pituitary or ectopic expression outside of pituitary, for example in some populations of neurons or gonads. Hence, these Cre strains often pose problems with regard to undesirable deletion of alleles in non-gonadotrope cells, fertility and germline transmission of mutant alleles. Here, we describe generation and characterization of a new Fshb-iCre deleter strain using 4.7 kb of ovine Fshb promoter regulatory sequences driving iCre expression exclusively in the gonadotrope lineage within anterior pituitary. Fshb-iCre mice develop normally, display no ectopic CRE expression in gonads and are fertile. When crossed onto a loxP recombination-mediated red to green color switch reporter mouse genetic background, in vivo CRE recombinase activity is detectable in gonadotropes at more than 95% efficiency and the GFP-tagged gonadotropes readily purified by fluorescence activated cell sorting. We demonstrate the applicability of this Fshb-iCre deleter strain in a mouse model in which Dicer is efficiently and selectively deleted in gonadotropes. We further show that loss of DICER-dependent miRNAs in gonadotropes leads to profound suppression of gonadotropins resulting in male and female infertility. Thus, Fshb-iCre mice serve as a new genetic tool to efficiently manipulate gonadotrope-specific gene expression in vivo.
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Affiliation(s)
- Huizhen Wang
- Department of Molecular and Integrative Physiology
| | | | - William L Miller
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - T Rajendra Kumar
- Department of Molecular and Integrative Physiology; Center for Reproductive Sciences, Institute for Reproductive Health and Regenerative Medicine; Department of Pathology and Laboratory Medicine; Department of Neurosurgery, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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8
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Wang H, Graham I, Hastings R, Gunewardena S, Brinkmeier ML, Conn PM, Camper SA, Kumar TR. Gonadotrope-specific deletion of Dicer results in severely suppressed gonadotropins and fertility defects. J Biol Chem 2014; 290:2699-714. [PMID: 25525274 DOI: 10.1074/jbc.m114.621565] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pituitary gonadotropins follicle-stimulating hormone and luteinizing hormone are heterodimeric glycoproteins expressed in gonadotropes. They act on gonads and promote their development and functions including steroidogenesis and gametogenesis. Although transcriptional regulation of gonadotropin subunits has been well studied, the post-transcriptional regulation of gonadotropin subunits is not well understood. To test if microRNAs regulate the hormone-specific gonadotropin β subunits in vivo, we deleted Dicer in gonadotropes by a Cre-lox genetic approach. We found that many of the DICER-dependent microRNAs, predicted in silico to bind gonadotropin β subunit mRNAs, were suppressed in purified gonadotropes of mutant mice. Loss of DICER-dependent microRNAs in gonadotropes resulted in profound suppression of gonadotropin-β subunit proteins and, consequently, the heterodimeric hormone secretion. In addition to suppression of basal levels, interestingly, the post-gonadectomy-induced rise in pituitary gonadotropin synthesis and secretion were both abolished in mutants, indicating a defective gonadal negative feedback control. Furthermore, mutants lacking Dicer in gonadotropes displayed severely reduced fertility and were rescued with exogenous hormones confirming that the fertility defects were secondary to suppressed gonadotropins. Our studies reveal that DICER-dependent microRNAs are essential for gonadotropin homeostasis and fertility in mice. Our studies also implicate microRNAs in gonadal feedback control of gonadotropin synthesis and secretion. Thus, DICER-dependent microRNAs confer a new layer of transcriptional and post-transcriptional regulation in gonadotropes to orchestrate the hypothalamus-pituitary-gonadal axis physiology.
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Affiliation(s)
- Huizhen Wang
- From the Departments of Molecular and Integrative Physiology
| | - Ian Graham
- From the Departments of Molecular and Integrative Physiology
| | - Richard Hastings
- Flow Cytometry Core Laboratory, University of Kansas Medical Center, Kansas City, Kansas 66160
| | | | - Michelle L Brinkmeier
- Department of Molecular and Human Genetics, University of Michigan, Ann Arbor, Michigan 48109, and
| | - P Michael Conn
- Departments of Internal Medicine, Cell Biology, and Biochemistry, Texas Tech University, Lubbock, Texas 79430
| | - Sally A Camper
- Department of Molecular and Human Genetics, University of Michigan, Ann Arbor, Michigan 48109, and
| | - T Rajendra Kumar
- From the Departments of Molecular and Integrative Physiology, Center for Reproductive Sciences, Institute for Reproductive Health and Regenerative Medicine, and
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Redirecting intracellular trafficking and the secretion pattern of FSH dramatically enhances ovarian function in mice. Proc Natl Acad Sci U S A 2014; 111:5735-40. [PMID: 24706813 DOI: 10.1073/pnas.1321404111] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
FSH and luteinizing hormone (LH) are secreted constitutively or in pulses, respectively, from pituitary gonadotropes in many vertebrates, and regulate ovarian function. The molecular basis for this evolutionarily conserved gonadotropin-specific secretion pattern is not understood. Here, we show that the carboxyterminal heptapeptide in LH is a gonadotropin-sorting determinant in vivo that directs pulsatile secretion. FSH containing this heptapeptide enters the regulated pathway in gonadotropes of transgenic mice, and is released in response to gonadotropin-releasing hormone, similar to LH. FSH released from the LH secretory pathway rescued ovarian defects in Fshb-null mice as efficiently as constitutively secreted FSH. Interestingly, the rerouted FSH enhanced ovarian follicle survival, caused a dramatic increase in number of ovulations, and prolonged female reproductive lifespan. Furthermore, the rerouted FSH vastly improved the in vivo fertilization competency of eggs, their subsequent development in vitro and when transplanted, the ability to produce offspring. Our study demonstrates the feasibility to fine-tune the target tissue responses by modifying the intracellular trafficking and secretory fate of a pituitary trophic hormone. The approach to interconvert the secretory fate of proteins in vivo has pathophysiological significance, and could explain the etiology of several hormone hyperstimulation and resistance syndromes.
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Jia J, Shafiee-Kermani F, Miller WL. Gonadotrope-specific expression and regulation of ovine follicle stimulating hormone Beta: transgenic and adenoviral approaches using primary murine gonadotropes. PLoS One 2013; 8:e66852. [PMID: 23874399 PMCID: PMC3715487 DOI: 10.1371/journal.pone.0066852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 05/13/2013] [Indexed: 01/21/2023] Open
Abstract
The beta subunit of follicle stimulating hormone (FSHB) is expressed specifically in pituitary gonadotropes in vertebrates. Transgenic mouse studies have shown that enhancers in the proximal promoter between −172/−1 bp of the ovine FSHB gene are required for gonadotrope expression of ovine FSHB. These enhancers are associated with regulation by activins and gonadotropin releasing hormone (GnRH). Additional distal promoter sequence between −4741/−750 bp is also required for expression. New transgenic studies presented here focus on this distal region and narrow it to 1116 bp between −1866/−750 bp. In addition, adenoviral constructs were produced to identify these critical distal sequences using purified primary mouse gonadotropes as an in vitro model system. The adenoviral constructs contained −2871 bp, −750 bp or −232 bp of the ovine FSHB promoter. They all showed gonadotrope-specific regulation since they were induced only in purified primary gonadotropes by activin A (50 ng/ml) and inhibited by GnRH (100 nM) in the presence of activin (except −232FSHBLuc). However, basal expression of all three viral constructs (in the presence of follistatin to block cellular induction by activin) was relatively high in pituitary non-gonadotropes as well as gonadotropes. Thus, gonadotrope-specific regulation associated with the proximal promoter was observed as expected, but the model was blind to distal promoter elements between −2871/−750 necessary for gonadotrope-specific expression of ovine FSHB in vivo. The new adenoviral-based in vitro technique did detect, however, a novel GnRH response element between −750 bp and −232 bp of the ovine FSHB promoter. We conclude that adenoviral-based studies in primary gonadotropes can adequately recognize regulatory elements on the ovine FSHB promoter associated with gonadotrope-specific regulation/expression, but that more physiologically based techniques, such as transgenic studies, will be needed to identify sequences between −1866/−750 bp of the ovine FSHB promoter that are also required for tissue/cell specific expression in vivo.
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Affiliation(s)
- Jingjing Jia
- Mount Sinai School of Medicine, Department of Neurology, New York City, New York, United States of America
| | - Farideh Shafiee-Kermani
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, United States of America
| | - William L. Miller
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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Bernard DJ, Tran S. Mechanisms of activin-stimulated FSH synthesis: the story of a pig and a FOX. Biol Reprod 2013; 88:78. [PMID: 23426431 DOI: 10.1095/biolreprod.113.107797] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Activins were discovered and, in fact, named more than a quarter century ago based on their abilities to stimulate pituitary follicle-stimulating hormone (FSH) synthesis and secretion. However, it is only in the last decade that we have finally come to understand their underlying mechanisms of action in gonadotroph cells. In this minireview, we chronicle the research that led to the recent discovery of forkhead box L2 (FOXL2) as an essential mediator of activin-regulated FSH beta subunit (Fshb) transcription in vitro and in vivo.
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Affiliation(s)
- Daniel J Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada.
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12
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Bi M, Tong J, Chang F, Wang J, Wei H, Dai Y, Chu M, Zhao Y, Li N. Pituitary-specific overexpression of porcine follicle-stimulating hormone leads to improvement of female fecundity in BAC transgenic mice. PLoS One 2012; 7:e42335. [PMID: 22860114 PMCID: PMC3409198 DOI: 10.1371/journal.pone.0042335] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/03/2012] [Indexed: 11/18/2022] Open
Abstract
Follicle-stimulating hormone (FSH) is a pituitary glycoprotein that, together with luteinizing hormone, plays a crucial role in ovarian folliculogenesis and female fertility. We previously found that FSH beta is a major gene controlling high prolificacy of Chinese Erhualian pigs. To directly study the biological effects on reproductive function of porcine FSH (pFSH) for polyovulatory species, we generated a novel gain-of-function mouse model using a bacterial artificial chromosome (BAC) system to jointly introduce 92 kb and 165 kb genomic fragments comprising the pFSH α- and β-subunit genes. These directed the physiological expression of pFSH with the same temporal and spatial pattern as endogenous FSH in female transgenic (TG) mice. Serum levels of biologically active pFSH heterodimers in independent TG lines ranged from 6.36 to 19.83 IU/L. High basal pFSH activity led to a significant reduction of serum LH and testosterone levels in TG females compared to wild-type (WT) littermates, yet endogenous FSH and estradiol levels were significantly elevated. Interestingly, ovarian histology showed that the number of corpora lutea was significantly higher at 14 and 28 weeks of age in TG females and breeding curves revealed that mean litter sizes of TG females were obviously larger than for WT littermates before 52 weeks of age. These findings indicate that pituitary-specific overexpression of pFSH within physiological boundaries can increase ovulation rate and litter size, but it does not cause reproductive defects. Therefore, our TG mouse model provides exciting insights for investigating the actions of pFSH in vivo.
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Affiliation(s)
- Mingjun Bi
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jia Tong
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Fei Chang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jing Wang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Hengxi Wei
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Sciences, South China Agricultural University, Guangzhou, China
| | - Yunping Dai
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Mingxing Chu
- Key Laboratory of Farm Animal Genetic Resources and Germplasm Innovation of Ministry of Agriculture Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yaofeng Zhao
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Ning Li
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
- * E-mail:
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Bernard DJ, Fortin J, Wang Y, Lamba P. Mechanisms of FSH synthesis: what we know, what we don't, and why you should care. Fertil Steril 2010; 93:2465-85. [DOI: 10.1016/j.fertnstert.2010.03.034] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 03/11/2010] [Indexed: 12/17/2022]
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Han SO, Miller WL. Activin A induces ovine follicle stimulating hormone beta using -169/-58 bp of its promoter and a simple TATA box. Reprod Biol Endocrinol 2009; 7:66. [PMID: 19552818 PMCID: PMC2714312 DOI: 10.1186/1477-7827-7-66] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 06/24/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Activin A increases production of follicle stimulating hormone (FSH) by inducing transcription of its beta subunit (FSHB). This induction has been studied here in LbetaT2 gonadotropes using transient expression of ovine FSHBLuc (-4741 bp of ovine FSHB promoter plus exon/intron 1 linked to Luc). Several sequences between -169/-58 bp of the ovine FSHB proximal promoter are necessary for induction by activin A in LbetaT2 cells, but deletions between -4741/-752 bp decrease induction > 70% suggesting the existence of other important 5' sequences. Induction disappears if a minimal T81 thymidine kinase promoter replaces the ovine FSHB TATA box and 3' exon/intron. The study reported here was designed to determine if sequences outside -169/-58 bp are important for induction of ovine FSHB by activin A. METHODS Progressively longer deletions of ovine FSHBLuc were created between -4741/-195 bp. Deletions internal to this region were created also, but replaced with substitute DNA. The ovine FSHB TATA box region (-40/+3 bp) was replaced by thymidine kinase and rat prolactin minimal promoters, and substitutions were made in 3' intron/exon sequences. All constructs were tested for basal and activin A-induced expression in LbetaT2 cells. RESULTS Successive 5' deletions progressively lowered fold-induction by activin A from 9.5 to zero, but progressively increased basal expression. Replacing deletions with substitute DNA showed no changes in basal expression or fold-induction. Induction by activin A was supported by the minimal rat prolactin promoter (TATA box) but not the thymidine kinase promoter (no TATA box). Replacement mutations in the 3' region did not decrease induction by activin A. CONCLUSION The data show that specific ovine FSHB sequences 5' to -175 bp or 3' of the transcription start site are not required for induction by activin A. A minimal TATA box promoter supports induction by activin A, but the sequence between the TATA box and transcription start site seems unimportant.
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Affiliation(s)
- Sang-oh Han
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, 27695-7622, USA
| | - William L Miller
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, 27695-7622, USA
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Kumar TR, Larson M, Wang H, McDermott J, Bronshteyn I. Transgenic mouse technology: principles and methods. Methods Mol Biol 2009; 590:335-62. [PMID: 19763515 DOI: 10.1007/978-1-60327-378-7_22] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Introduction of foreign DNA into the mouse germ line is considered a major technical advancement in the fields of developmental biology and genetics. This technology now referred to as transgenic mouse technology has revolutionized virtually all fields of biology and provided new genetic approaches to model many human diseases in a whole animal context. Several hundreds of transgenic lines with expression of foreign genes specifically targeted to desired organelles/cells/tissues have been characterized. Further, the ability to spatio-temporally inactivate or activate gene expression in vivo using the "Cre-lox" technology has recently emerged as a powerful approach to understand various developmental processes including those relevant to molecular endocrinology. In this chapter, we will discuss the principles of transgenic mouse technology, and describe detailed methodology standardized at our institute.
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Affiliation(s)
- T Rajendra Kumar
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
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Wang Y, Fortin J, Lamba P, Bonomi M, Persani L, Roberson MS, Bernard DJ. Activator protein-1 and smad proteins synergistically regulate human follicle-stimulating hormone beta-promoter activity. Endocrinology 2008; 149:5577-91. [PMID: 18653705 PMCID: PMC2584589 DOI: 10.1210/en.2008-0220] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GnRH1 stimulates the synthesis and secretion of FSH and LH from the anterior pituitary gland. The molecular mechanisms through which GnRH1 produces these effects in humans have not been determined. Here, we examined transcriptional regulation of the human FSHbeta (FSHB) subunit using reporter assays in immortalized murine gonadotrope cells. GnRH1 dose and time dependently stimulated FSHB promoter activity, with peak stimulation occurring at 8 h. GnRH1 rapidly stimulated various MAPK cascades, though the ERK1/2 and p38 pathways appeared to be most critical for FSHB induction. Indeed, constitutively active forms of both Raf1 kinase and MAP2K6 (MKK6) were sufficient to stimulate reporter activity. GnRH1 stimulated activator protein-1 (AP-1) (FosB, c-fos, JunB, and cJun) synthesis and complex formation, the latter of which bound to a conserved cis-element within -120 bp of the transcription start site. A second, lower affinity, site was mapped more proximally. Mutations of both cis-elements diminished GnRH1-stimulated promoter activity, though disruption of the higher affinity site had a more dramatic effect. A dominant-negative Fos protein dose dependently inhibited GnRH1-stimulated FSHB transcription, confirming a role for endogenous AP-1 proteins. MAPK kinase 1 (MEK1) and p38 inhibitors significantly attenuated GnRH1-stimulated c-fos, FosB, and JunB synthesis, suggesting a mechanism whereby the ERK1/2 and p38 signaling pathways regulate FSHB transcription. Activins and inhibins potently regulate FSH synthesis in rodents, but their roles in FSH regulation in humans are less clear. Activin A, though weak on its own, synergized with GnRH1 to stimulate human FSHB promoter activity. In contrast, activin A partially inhibited GnRH1-stimulated LHbeta subunit (LHB) transcription. The GnRH1 and activin A signaling pathways appear to converge at the level of the high-affinity AP-1 site. Fos and Jun proteins synergistically regulate reporter activity through this element, and their effects are potentiated by coexpression of either Smad2 or Smad3, effectors in the activin signaling cascade. In summary, GnRH1 and activin A synergistically regulate human FSHB subunit transcription. The combined actions of AP-1 and Smad proteins acting through a conserved AP-1 element provide a candidate mechanism for this effect. The ability of activins to potentiate selectively the effects of GnRH1 on FSHB expression suggests a model for preferential increases in FSH secretion at the luteal-follicular transition of the menstrual cycle.
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Affiliation(s)
- Ying Wang
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada. daniel
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Lamba P, Khivansara V, D'Alessio AC, Santos MM, Bernard DJ. Paired-like homeodomain transcription factors 1 and 2 regulate follicle-stimulating hormone beta-subunit transcription through a conserved cis-element. Endocrinology 2008; 149:3095-108. [PMID: 18339718 PMCID: PMC2408822 DOI: 10.1210/en.2007-0425] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Accepted: 03/03/2008] [Indexed: 11/19/2022]
Abstract
Paired-like homeodomain transcription factors (PITX) regulate the activity of pituitary hormone-encoding genes. Here, we examined mechanisms through which the family of PITX proteins control murine FSH beta-subunit (Fshb) transcription. We observed that endogenous PITX1 and PITX2 isoforms from murine LbetaT2 gonadotrope cells could bind a highly conserved proximal cis-element. Transfection of PITX1 or PITX2C in heterologous cells stimulated both murine and human Fshb/FSHB promoter-reporter activities, and in both cases, mutation of the critical cis-element abrogated these effects. In homologous LbetaT2 cells, the same mutation decreased basal reporter activity and greatly reduced activin A-stimulated transcription from murine and human promoter-reporters. Transfecting dominant-negative forms of PITX1 or PITX2C or knocking down PITX1 or -2 expression by RNA interference in LbetaT2 cells inhibited murine Fshb transcription, confirming roles for endogenous PITX proteins. Both PITX1 and PITX2C interacted with Smad3 (an effector of the activin signaling cascade in these cells) in coprecipitation experiments, and the PITX binding site mutation greatly inhibited Smad2/3/4-stimulated Fshb transcription. In summary, both PITX1 and PITX2C regulate murine and human Fshb/FSHB transcription through a conserved cis-element in the proximal promoter. Furthermore, the data indicate both common and distinct mechanisms of PITX1 and PITX2C action.
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Affiliation(s)
- Pankaj Lamba
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Sciences Building, Montreal, Quebec, Canada H3G 1Y6
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Kumar TR. Mouse models for gonadotropins: a 15-year saga. Mol Cell Endocrinol 2007; 260-262:249-54. [PMID: 17055639 DOI: 10.1016/j.mce.2006.09.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2006] [Accepted: 04/27/2006] [Indexed: 11/24/2022]
Abstract
Pituitary gonadotropins FSH and LH are heterodimeric glycoproteins consisting of a common alpha and a hormone-specific beta subunit that are non-covalently linked. Both these hormones bind G-protein coupled receptors and regulate multiple processes in the gonads. Advances in the past two decades in manipulating the mouse genome by random and site-specific mutagenesis have been invaluable to our understanding of the biology of gonadotropins. Using these transgenic and gene targeting approaches, both gain-of-function transgenic as well as knockout mice lacking the hormone-specific gonadotropin subunits, and hence functional dimeric hormones were generated. Furthermore, knockout mice lacking regulators of gonadotropin production have also been characterized. These mice are useful to delineate the distinct in vivo biological roles of FSH and LH, and provide valuable genetic tools to study the signaling mechanisms within the gonads. Here, I will discuss our work on different ways to manipulate gonadotropin ligand function in the mouse.
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Affiliation(s)
- T Rajendra Kumar
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas, KS 66160, USA.
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