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Ongaro L, Zhou X, Cui Y, Boehm U, Bernard DJ. Gonadotrope-specific deletion of the BMP type 2 receptor does not affect reproductive physiology in mice†‡. Biol Reprod 2021; 102:639-646. [PMID: 31724029 DOI: 10.1093/biolre/ioz206] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 10/19/2019] [Accepted: 10/22/2019] [Indexed: 02/06/2023] Open
Abstract
Activins selectively stimulate follicle-stimulating hormone (FSH) secretion by pituitary gonadotrope cells. More recently, other members of the TGFbeta superfamily, the bone morphogenetic proteins (BMPs), were reported to regulate FSH synthesis. Activins and BMPs independently and synergistically stimulate transcription of the FSHbeta subunit (Fshb) gene in immortalized gonadotrope-like cells. Both ligands can signal via the activin receptor type IIA (ACVR2A) to regulate FSH synthesis in vitro. In vivo, global Acvr2a knockout mice exhibit a 60% reduction in circulating FSH relative to wild-type animals, suggesting that activins, BMPs, or related ligands might signal through additional type II receptors to regulate FSH in vivo. Although the leading candidates are ACVR2B and the BMP type II receptor (BMPR2), only the latter mediates activin or BMP2 induction of Fshb transcription in vitro. Here, we generated mice carrying a loss of function mutation in Bmpr2 specifically in gonadotropes. Puberty onset, estrous cyclicity, and reproductive organ weights were similar between control and conditional knockout females. Serum FSH and luteinizing hormone (LH) and pituitary expression of Fshb and the LHbeta subunit (Lhb) were similarly unaffected by the gene deletion in both sexes. These results suggest that BMPR2 might not play a necessary role in FSH synthesis or secretion in vivo or that another type II receptor, such as ACVR2A, can fully compensate for its absence. These data also further contribute to the emerging concept that BMPs may not be physiological regulators of FSH in vivo.
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Affiliation(s)
- Luisina Ongaro
- Department of Pharmacology and Therapeutics.,Centre for Research in Reproduction and Development, McGill University, Montreal, QC, Canada
| | - Xiang Zhou
- Department of Pharmacology and Therapeutics.,Centre for Research in Reproduction and Development, McGill University, Montreal, QC, Canada
| | - Yiming Cui
- Department of Pharmacology and Therapeutics.,Centre for Research in Reproduction and Development, McGill University, Montreal, QC, Canada
| | - Ulrich Boehm
- Department of Pharmacology and Toxicology, Saarland University School of Medicine, Homburg, Germany
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics.,Centre for Research in Reproduction and Development, McGill University, Montreal, QC, Canada
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2
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Li Y, Schang G, Wang Y, Zhou X, Levasseur A, Boyer A, Deng CX, Treier M, Boehm U, Boerboom D, Bernard DJ. Conditional Deletion of FOXL2 and SMAD4 in Gonadotropes of Adult Mice Causes Isolated FSH Deficiency. Endocrinology 2018; 159:2641-2655. [PMID: 29800110 PMCID: PMC6692885 DOI: 10.1210/en.2018-00100] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/15/2018] [Indexed: 12/24/2022]
Abstract
The glycoprotein FSH, a product of pituitary gonadotrope cells, regulates ovarian follicle development in females and spermatogenesis in males. FSH is a heterodimer of the common α gonadotropin subunit and the hormone-specific FSHβ subunit (a product of the Fshb gene). Using a conditional knockout approach (Cre-lox), we previously demonstrated that Fshb expression in mice depends on the transcription factors forkhead box L2 (FOXL2) and SMAD4. Deletion of Foxl2 or Smad4 alone led to FSH deficiency, female subfertility, and oligozoospermia in males. Simultaneous deletion of the two genes yielded a greater suppression of FSH and female sterility. The Cre-driver used previously was first active during embryonic development. Therefore, it is unclear whether FOXL2 and SMAD4 play important roles in the development or adult function of gonadotropes, or both. To address this question, we developed a tamoxifen-inducible Cre-driver line, which enabled Foxl2 and Smad4 gene deletions in gonadotropes of adult mice. After tamoxifen treatment, females with previously demonstrated fertility exhibited profound reductions in FSH levels, arrested ovarian follicle development, and sterility. FSH levels were comparably reduced in males 1 or 2 months after treatment; however, spermatogenesis was unaffected. These data indicate that (1) FOXL2 and SMAD4 are necessary to maintain FSH synthesis in gonadotrope cells of adult mice, (2) FSH is essential for female reproduction but appears to be unnecessary for the maintenance of spermatogenesis in adult male mice, and (3) the inducible Cre-driver line developed here provides a powerful tool to interrogate gene function in gonadotrope cells of adult mice.
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Affiliation(s)
- Yining Li
- Department of Pharmacology & Therapeutics, McGill University, Montréal, Québec, Canada
| | - Gauthier Schang
- Department of Pharmacology & Therapeutics, McGill University, Montréal, Québec, Canada
| | - Ying Wang
- Department of Pharmacology & Therapeutics, McGill University, Montréal, Québec, Canada
| | - Xiang Zhou
- Department of Pharmacology & Therapeutics, McGill University, Montréal, Québec, Canada
| | - Adrien Levasseur
- Département de Biomédecine Vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada
| | - Alexandre Boyer
- Département de Biomédecine Vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada
| | - Chu-Xia Deng
- Faculty of Health Sciences, University of Macau, Macau, China
| | - Mathias Treier
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin-Buch, Germany
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ulrich Boehm
- Department of Experimental Pharmacology, Center for Molecular Signaling, Saarland University School of Medicine, Homburg, Germany
| | - Derek Boerboom
- Département de Biomédecine Vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada
| | - Daniel J Bernard
- Department of Pharmacology & Therapeutics, McGill University, Montréal, Québec, Canada
- Correspondence: Daniel J. Bernard, PhD, Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Room 1315, Montréal, Quebec H3G 1Y6, Canada. E-mail:
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3
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Li Y, Schang G, Boehm U, Deng CX, Graff J, Bernard DJ. SMAD3 Regulates Follicle-stimulating Hormone Synthesis by Pituitary Gonadotrope Cells in Vivo. J Biol Chem 2016; 292:2301-2314. [PMID: 27994055 DOI: 10.1074/jbc.m116.759167] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/16/2016] [Indexed: 12/20/2022] Open
Abstract
Pituitary follicle-stimulating hormone (FSH) is an essential regulator of fertility in females and of quantitatively normal spermatogenesis in males. Pituitary-derived activins are thought to act as major stimulators of FSH synthesis by gonadotrope cells. In vitro, activins signal via SMAD3, SMAD4, and forkhead box L2 (FOXL2) to regulate transcription of the FSHβ subunit gene (Fshb). Consistent with this model, gonadotrope-specific Smad4 or Foxl2 knock-out mice have greatly reduced FSH and are subfertile. The role of SMAD3 in vivo is unresolved; however, residual FSH production in Smad4 conditional knock-out mice may derive from partial compensation by SMAD3 and its ability to bind DNA in the absence of SMAD4. To test this hypothesis and determine the role of SMAD3 in FSH biosynthesis, we generated mice lacking both the SMAD3 DNA binding domain and SMAD4 specifically in gonadotropes. Conditional knock-out females were hypogonadal, acyclic, and sterile and had thread-like uteri; their ovaries lacked antral follicles and corpora lutea. Knock-out males were fertile but had reduced testis weights and epididymal sperm counts. These phenotypes were consistent with those of Fshb knock-out mice. Indeed, pituitary Fshb mRNA levels were nearly undetectable in both male and female knock-outs. In contrast, gonadotropin-releasing hormone receptor mRNA levels were significantly elevated in knock-outs in both sexes. Interestingly, luteinizing hormone production was altered in a sex-specific fashion. Overall, our analyses demonstrate that SMAD3 is required for FSH synthesis in vivo.
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Affiliation(s)
- Yining Li
- From the Centre for Research in Reproduction and Development, Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Gauthier Schang
- From the Centre for Research in Reproduction and Development, Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Ulrich Boehm
- the Department of Pharmacology and Toxicology, University of Saarland School of Medicine, D-66421 Homburg, Germany
| | - Chu-Xia Deng
- the Faculty of Health Sciences, University of Macau, Macau SAR 999078, China, and
| | - Jonathan Graff
- the Department of Developmental Biology, University of Texas Southwestern, Dallas, Texas 75390
| | - Daniel J Bernard
- From the Centre for Research in Reproduction and Development, Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada,
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Fortin J, Ongaro L, Li Y, Tran S, Lamba P, Wang Y, Zhou X, Bernard DJ. Minireview: Activin Signaling in Gonadotropes: What Does the FOX say… to the SMAD? Mol Endocrinol 2015; 29:963-77. [PMID: 25942106 DOI: 10.1210/me.2015-1004] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The activins were discovered and named based on their abilities to stimulate FSH secretion and FSHβ (Fshb) subunit expression by pituitary gonadotrope cells. According to subsequent in vitro observations, activins also stimulate the transcription of the GnRH receptor (Gnrhr) and the activin antagonist, follistatin (Fst). Thus, not only do activins stimulate FSH directly, they have the potential to regulate both FSH and LH indirectly by modulating gonadotrope sensitivity to hypothalamic GnRH. Moreover, activins may negatively regulate their own actions by stimulating the production of one of their principal antagonists. Here, we describe our current understanding of the mechanisms through which activins regulate Fshb, Gnrhr, and Fst transcription in vitro. The activin signaling molecules SMAD3 and SMAD4 appear to partner with the winged-helix/forkhead transcription factor, forkhead box L2 (FOXL2), to regulate expression of all 3 genes. However, in vivo data paint a different picture. Although conditional deletion of Foxl2 and/or Smad4 in murine gonadotropes produces impairments in FSH synthesis and secretion as well as in pituitary Fst expression, Gnrhr mRNA levels are either unperturbed or increased in these animals. Surprisingly, gonadotrope-specific deletion of Smad3 alone or with Smad2 does not impair FSH production or fertility; however, mice harboring these mutations may express a DNA binding-deficient, but otherwise functional, SMAD3 protein. Collectively, the available data firmly establish roles for FOXL2 and SMAD4 in Fshb and Fst expression in gonadotrope cells, whereas SMAD3's role requires further investigation. Gnrhr expression, in contrast, appears to be FOXL2, SMAD4, and, perhaps, activin independent in vivo.
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Affiliation(s)
- Jérôme Fortin
- Department of Pharmacology and Therapeutics (J.F., L.O., Y.L., S.T., P.L., Y.W., X.Z., D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6; The Campbell Family Cancer Research Institute (J.F.), Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2C1; Diabetes Center (S.T.), Department of Medicine, University of California-San Francisco, San Francisco, California 94143; and Psychiatry (P.L.), St Mary Mercy Hospital, Livonia, Michigan 48154
| | - Luisina Ongaro
- Department of Pharmacology and Therapeutics (J.F., L.O., Y.L., S.T., P.L., Y.W., X.Z., D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6; The Campbell Family Cancer Research Institute (J.F.), Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2C1; Diabetes Center (S.T.), Department of Medicine, University of California-San Francisco, San Francisco, California 94143; and Psychiatry (P.L.), St Mary Mercy Hospital, Livonia, Michigan 48154
| | - Yining Li
- Department of Pharmacology and Therapeutics (J.F., L.O., Y.L., S.T., P.L., Y.W., X.Z., D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6; The Campbell Family Cancer Research Institute (J.F.), Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2C1; Diabetes Center (S.T.), Department of Medicine, University of California-San Francisco, San Francisco, California 94143; and Psychiatry (P.L.), St Mary Mercy Hospital, Livonia, Michigan 48154
| | - Stella Tran
- Department of Pharmacology and Therapeutics (J.F., L.O., Y.L., S.T., P.L., Y.W., X.Z., D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6; The Campbell Family Cancer Research Institute (J.F.), Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2C1; Diabetes Center (S.T.), Department of Medicine, University of California-San Francisco, San Francisco, California 94143; and Psychiatry (P.L.), St Mary Mercy Hospital, Livonia, Michigan 48154
| | - Pankaj Lamba
- Department of Pharmacology and Therapeutics (J.F., L.O., Y.L., S.T., P.L., Y.W., X.Z., D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6; The Campbell Family Cancer Research Institute (J.F.), Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2C1; Diabetes Center (S.T.), Department of Medicine, University of California-San Francisco, San Francisco, California 94143; and Psychiatry (P.L.), St Mary Mercy Hospital, Livonia, Michigan 48154
| | - Ying Wang
- Department of Pharmacology and Therapeutics (J.F., L.O., Y.L., S.T., P.L., Y.W., X.Z., D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6; The Campbell Family Cancer Research Institute (J.F.), Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2C1; Diabetes Center (S.T.), Department of Medicine, University of California-San Francisco, San Francisco, California 94143; and Psychiatry (P.L.), St Mary Mercy Hospital, Livonia, Michigan 48154
| | - Xiang Zhou
- Department of Pharmacology and Therapeutics (J.F., L.O., Y.L., S.T., P.L., Y.W., X.Z., D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6; The Campbell Family Cancer Research Institute (J.F.), Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2C1; Diabetes Center (S.T.), Department of Medicine, University of California-San Francisco, San Francisco, California 94143; and Psychiatry (P.L.), St Mary Mercy Hospital, Livonia, Michigan 48154
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics (J.F., L.O., Y.L., S.T., P.L., Y.W., X.Z., D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6; The Campbell Family Cancer Research Institute (J.F.), Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2C1; Diabetes Center (S.T.), Department of Medicine, University of California-San Francisco, San Francisco, California 94143; and Psychiatry (P.L.), St Mary Mercy Hospital, Livonia, Michigan 48154
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5
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Faucz FR, Horvath AD, Azevedo MF, Levy I, Bak B, Wang Y, Xekouki P, Szarek E, Gourgari E, Manning AD, de Alexandre RB, Saloustros E, Trivellin G, Lodish M, Hofman P, Anderson YC, Holdaway I, Oldfield E, Chittiboina P, Nesterova M, Biermasz NR, Wit JM, Bernard DJ, Stratakis CA. Is IGSF1 involved in human pituitary tumor formation? Endocr Relat Cancer 2015; 22:47-54. [PMID: 25527509 PMCID: PMC4272759 DOI: 10.1530/erc-14-0465] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
IGSF1 is a membrane glycoprotein highly expressed in the anterior pituitary. Pathogenic mutations in the IGSF1 gene (on Xq26.2) are associated with X-linked central hypothyroidism and testicular enlargement in males. In this study, we tested the hypothesis that IGSF1 is involved in the development of pituitary tumors, especially those that produce growth hormone (GH). IGSF1 was sequenced in 21 patients with gigantism or acromegaly and 92 healthy individuals. Expression studies with a candidate pathogenic IGSF1 variant were carried out in transfected cells and immunohistochemistry for IGSF1 was performed in the sections of GH-producing adenomas, familial somatomammotroph hyperplasia, and in normal pituitary. We identified the sequence variant p.N604T, which in silico analysis suggested could affect IGSF1 function, in two male patients and one female with somatomammotroph hyperplasia from the same family. Of 60 female controls, two carried the same variant and seven were heterozygous for other variants. Immunohistochemistry showed increased IGSF1 staining in the GH-producing tumor from the patient with the IGSF1 p.N604T variant compared with a GH-producing adenoma from a patient negative for any IGSF1 variants and with normal control pituitary tissue. The IGSF1 gene appears polymorphic in the general population. A potentially pathogenic variant identified in the germline of three patients with gigantism from the same family (segregating with the disease) was also detected in two healthy female controls. Variations in IGSF1 expression in pituitary tissue in patients with or without IGSF1 germline mutations point to the need for further studies of IGSF1 action in pituitary adenoma formation.
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Affiliation(s)
- Fabio R. Faucz
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
- Group for Advanced Molecular Investigation, Graduate Program in Health Science, Medical School, Pontificia Universidade Catolica do Paraná, Curitiba, PR, 80215, Brazil
| | - Anelia D. Horvath
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Monalisa F. Azevedo
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Isaac Levy
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Beata Bak
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada, H3G 1Y6
| | - Ying Wang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada, H3G 1Y6
| | - Paraskevi Xekouki
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Eva Szarek
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Evgenia Gourgari
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
- Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD20892, USA
| | - Allison D. Manning
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Rodrigo Bertollo de Alexandre
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
- Group for Advanced Molecular Investigation, Graduate Program in Health Science, Medical School, Pontificia Universidade Catolica do Paraná, Curitiba, PR, 80215, Brazil
| | - Emmanouil Saloustros
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Giampaolo Trivellin
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Maya Lodish
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Paul Hofman
- The Liggins Institute, University of Auckland, Auckland, New Zealand, 1023
| | - Yvonne C Anderson
- The Liggins Institute, University of Auckland, Auckland, New Zealand, 1023
- Taranaki Base Hospital, New Plymouth, New Zealand, 4310
| | - Ian Holdaway
- Auckland City Hospital & Greenlane Clinical Centre, Auckland, New Zealand, 1142
| | - Edward Oldfield
- Department of Neurosurgery, University of Virginia Health Sciences Center, University of Virginia, Charlottesville, Virginia, 22904
| | - Prashant Chittiboina
- Surgical Neurology Branch, National Institute for Neurological Diseases and Stroke (NINDS), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Maria Nesterova
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Nienke R. Biermasz
- Department of Endocrinology & Metabolic Disorders, Leiden University Medical Center, Leiden, The Netherlands, 2333
| | - Jan M. Wit
- Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands, 2333
| | - Daniel J. Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada, H3G 1Y6
| | - Constantine A. Stratakis
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology & Genetics (PDEGEN) Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
- Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD20892, USA
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6
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Wang Y, Ho CC, Bang E, Rejon CA, Libasci V, Pertchenko P, Hébert TE, Bernard DJ. Bone morphogenetic protein 2 stimulates noncanonical SMAD2/3 signaling via the BMP type 1A receptor in gonadotrope-like cells: implications for FSH synthesis. Endocrinology 2014; 155:1970-81. [PMID: 24601881 DOI: 10.1210/en.2013-1741] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
FSH is an essential regulator of mammalian reproduction. Its synthesis by pituitary gonadotrope cells is regulated by multiple endocrine and paracrine factors, including TGFβ superfamily ligands, such as the activins and inhibins. Activins stimulate FSH synthesis via transcriptional regulation of its β-subunit gene (Fshb). More recently, bone morphogenetic proteins (BMPs) were shown to stimulate murine Fshb transcription alone and in synergy with activins. BMP2 signals via its canonical type I receptor, BMPR1A (or activin receptor-like kinase 3 [ALK3]), and SMAD1 and SMAD5 to stimulate transcription of inhibitor of DNA binding proteins. Inhibitor of DNA binding proteins then potentiate the actions of activin-stimulated SMAD3 to regulate the Fshb gene in the gonadotrope-like LβT2 cell line. Here, we report the unexpected observation that BMP2 also stimulates the SMAD2/3 pathway in these cells and that it does so directly via ALK3. Indeed, this novel, noncanonical ALK3 activity is completely independent of ALK4, ALK5, and ALK7, the type I receptors most often associated with SMAD2/3 pathway activation. Induction of the SMAD2/3 pathway by ALK3 is dependent upon its own previous activation by associated type II receptors, which phosphorylate conserved serine and threonine residues in the ALK3 juxtamembrane glycine-serine-rich domain. ALK3 signaling via SMAD3 is necessary for the receptor to stimulate Fshb transcription, whereas its activation of the SMAD1/5/8 pathway alone is insufficient. These data challenge current dogma that ALK3 and other BMP type I receptors signal via SMAD1, SMAD5, and SMAD8 and not SMAD2 or SMAD3. Moreover, they suggest that BMPs and activins may use similar intracellular signaling mechanisms to activate the murine Fshb promoter in immortalized gonadotrope-like cells.
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MESH Headings
- Activins/antagonists & inhibitors
- Activins/metabolism
- Animals
- Bone Morphogenetic Protein 2/agonists
- Bone Morphogenetic Protein 2/antagonists & inhibitors
- Bone Morphogenetic Protein 2/genetics
- Bone Morphogenetic Protein 2/metabolism
- Bone Morphogenetic Protein Receptors, Type I/agonists
- Bone Morphogenetic Protein Receptors, Type I/antagonists & inhibitors
- Bone Morphogenetic Protein Receptors, Type I/genetics
- Bone Morphogenetic Protein Receptors, Type I/metabolism
- Cell Line
- Follicle Stimulating Hormone, beta Subunit/biosynthesis
- Follicle Stimulating Hormone, beta Subunit/genetics
- Follicle Stimulating Hormone, beta Subunit/metabolism
- Gene Silencing
- Genes, Reporter
- Gonadotrophs/metabolism
- Humans
- Mice
- Phosphorylation
- Protein Processing, Post-Translational
- RNA, Small Interfering
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Signal Transduction
- Smad2 Protein/antagonists & inhibitors
- Smad2 Protein/genetics
- Smad2 Protein/metabolism
- Smad3 Protein/antagonists & inhibitors
- Smad3 Protein/genetics
- Smad3 Protein/metabolism
- Transcription, Genetic
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Affiliation(s)
- Ying Wang
- Departments of Pharmacology and Therapeutics (Y.W., C.C.H., E.B., C.A.R., V.L., P.P., T.E.H., D.J.B.), Oncology (C.A.R.), Obstetrics and Gynecology (D.J.B.), and Anatomy and Cell Biology (D.J.B.), McGill University, Montréal, Québec, Canada H3G 1Y6
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7
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Fortin J, Boehm U, Deng CX, Treier M, Bernard DJ. Follicle-stimulating hormone synthesis and fertility depend on SMAD4 and FOXL2. FASEB J 2014; 28:3396-410. [PMID: 24739304 DOI: 10.1096/fj.14-249532] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Follicle-stimulating hormone (FSH) is an essential regulator of gonadal function and fertility. Loss-of-function mutations in the FSHB/Fshb gene cause hypogonadotropic hypogonadism in humans and mice. Both gonadotropin-releasing hormone (GnRH) and activins, members of the transforming growth factor β (TGFβ) superfamily, stimulate FSH synthesis; yet, their relative roles and mechanisms of action in vivo are unknown. Here, using conditional gene-targeting, we show that the canonical mediator of TGFβ superfamily signaling, SMAD4, is absolutely required for normal FSH synthesis in both male and female mice. Moreover, when the Smad4 gene is ablated in combination with its DNA binding cofactor Foxl2 in gonadotrope cells, mice make essentially no FSH and females are sterile. Indeed, the phenotype of these animals is remarkably similar to that of Fshb-knockout mice. Not only do these results establish SMAD4 and FOXL2 as essential master regulators of Fshb transcription in vivo, they also suggest that activins, or related ligands, could play more important roles in FSH synthesis than GnRH.
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Affiliation(s)
- Jérôme Fortin
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada;
| | - Ulrich Boehm
- Department of Pharmacology and Toxicology, University of Saarland School of Medicine, Homburg, Germany
| | - Chu-Xia Deng
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA; and
| | - Mathias Treier
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada;
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Fortin J, Boehm U, Weinstein MB, Graff JM, Bernard DJ. Follicle-stimulating hormone synthesis and fertility are intact in mice lacking SMAD3 DNA binding activity and SMAD2 in gonadotrope cells. FASEB J 2013; 28:1474-85. [PMID: 24308975 DOI: 10.1096/fj.13-237818] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The activin/inhibin system regulates follicle-stimulating hormone (FSH) synthesis and release by pituitary gonadotrope cells in mammals. In vitro cell line data suggest that activins stimulate FSH β-subunit (Fshb) transcription via complexes containing the receptor-regulated SMAD proteins SMAD2 and SMAD3. Here, we used a Cre-loxP approach to determine the necessity for SMAD2 and/or SMAD3 in FSH synthesis in vivo. Surprisingly, mice with conditional mutations in both Smad2 and Smad3 specifically in gonadotrope cells are fertile and produce FSH at quantitatively normal levels. Notably, however, we discovered that the recombined Smad3 allele produces a transcript that encodes the entirety of the SMAD3 C-terminal Mad homology 2 (MH2) domain. This protein behaves similarly to full-length SMAD3 in Fshb transcriptional assays. As the truncated protein lacks the N-terminal Mad homology 1 (MH1) domain, these results show that SMAD3 DNA-binding activity as well as SMAD2 are dispensable for normal FSH synthesis in vivo. Furthermore, the observation that deletion of proximal exons does not remove all SMAD3 function may facilitate interpretation of divergent phenotypes previously described in different Smad3 knockout mouse lines.
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Affiliation(s)
- Jérôme Fortin
- 1Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Rm. 1315, Montréal, QC, H3G 1Y6, Canada. J.F.,
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9
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Rejon CA, Hancock MA, Li YN, Thompson TB, Hébert TE, Bernard DJ. Activins bind and signal via bone morphogenetic protein receptor type II (BMPR2) in immortalized gonadotrope-like cells. Cell Signal 2013; 25:2717-26. [PMID: 24018044 DOI: 10.1016/j.cellsig.2013.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/15/2013] [Accepted: 09/01/2013] [Indexed: 11/25/2022]
Abstract
TGFβ superfamily ligands greatly outnumber their receptors. Thus, receptors are shared between ligands and individual ligands can bind multiple receptors. Bone morphogenetic proteins (BMPs) bind and signal via both BMP type II (BMPR2) and activin type II (ACVR2) receptors. We hypothesized that, in addition to its canonical receptor ACVR2, activin A might similarly bind and signal via BMPR2. First, using surface plasmon resonance, we showed that activin A binds to the BMPR2 extracellular domain (ECD), though with lower affinity compared to the ACVR2-ECD. We confirmed these results in cells, where radiolabeled activin A bound to ACVR2 and BMPR2, but not to other type II receptors (AMHR2 or TGFBR2). Using homology modeling and site-directed mutagenesis, we identified key residues in BMPR2 that mediate its interaction with activin A. The soluble ECDs of ACVR2 or BMPR2 dose-dependently inhibited activin A-, but not TGFβ-induced signaling in cells, suggesting that activin binding to BMPR2 could have functional consequences. To address this idea, we altered BMPR2 expression levels in immortalized murine gonadotrope-like cells, LβT2, in which activins potently stimulate follicle-stimulating hormone β (Fshb) subunit transcription. BMPR2 expression potentiated activin A responses whereas depletion of endogenous BMPR2 with short interfering RNAs attenuated activin A-stimulated Fshb transcription. Additional data suggest, for the first time, that BMPR2 may form functional complexes with the canonical activin type I receptor, activin receptor-like kinase 4. Collectively, our data show that BMPR2, along with ACVR2, functions as a bona fide activin type II receptor in gonadotrope-like cells, thereby broadening our understanding of mechanisms of activin action.
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Affiliation(s)
- Carlis A Rejon
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
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