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Stamou MI, Chiu CJ, Jadhav SV, Lopes VF, Salnikov KB, Plummer L, Lippincott MF, Lee H, Seminara SB, Balasubramanian R. Defective FGFR1 Signaling Disrupts Glucose Regulation: Evidence From Humans With FGFR1 Mutations. J Endocr Soc 2024; 8:bvae118. [PMID: 38957656 PMCID: PMC11216325 DOI: 10.1210/jendso/bvae118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Indexed: 07/04/2024] Open
Abstract
Context Activation of fibroblast growth factor receptor 1 (FGFR1) signaling improves the metabolic health of animals and humans, while inactivation leads to diabetes in mice. Direct human genetic evidence for the role of FGFR1 signaling in human metabolic health has not been fully established. Objective We hypothesized that individuals with naturally occurring FGFR1 variants ("experiments of nature") will display glucose dysregulation. Methods Participants with rare FGFR1 variants and noncarrier controls. Using a recall-by-genotype approach, we examined the β-cell function and insulin sensitivity of 9 individuals with rare FGFR1 deleterious variants compared to 27 noncarrier controls, during a frequently sampled intravenous glucose tolerance test at the Reproductive Endocrine Unit and the Harvard Center for Reproductive Medicine, Massachusetts General Hospital. FGFR1-mutation carriers displayed higher β-cell function in the face of lower insulin sensitivity compared to controls. Conclusion These findings suggest that impaired FGFR1 signaling may contribute to an early insulin resistance phase of diabetes pathogenesis and support the candidacy of the FGFR1 signaling pathway as a therapeutic target for improving the human metabolic health.
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Affiliation(s)
- Maria I Stamou
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Crystal J Chiu
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Shreya V Jadhav
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Vanessa Ferreira Lopes
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Kathryn B Salnikov
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Lacey Plummer
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Margaret F Lippincott
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Hang Lee
- MGH Biostatistics Center and MGH Division of Clinical Research (DCR) Biostatistics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Stephanie B Seminara
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Ravikumar Balasubramanian
- Reproductive Endocrine Unit and Harvard Center for Reproductive Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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2
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Chung WCJ, Tsai PS. The initiation and maintenance of gonadotropin-releasing hormone neuron identity in congenital hypogonadotropic hypogonadism. Front Endocrinol (Lausanne) 2023; 14:1166132. [PMID: 37181038 PMCID: PMC10173152 DOI: 10.3389/fendo.2023.1166132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/12/2023] [Indexed: 05/16/2023] Open
Abstract
Neurons that secrete gonadotropin-releasing hormone (GnRH) drive vertebrate reproduction. Genetic lesions that disrupt these neurons in humans lead to congenital hypogonadotropic hypogonadism (CHH) and reproductive failure. Studies on CHH have largely focused on the disruption of prenatal GnRH neuronal migration and postnatal GnRH secretory activity. However, recent evidence suggests a need to also focus on how GnRH neurons initiate and maintain their identity during prenatal and postnatal periods. This review will provide a brief overview of what is known about these processes and several gaps in our knowledge, with an emphasis on how disruption of GnRH neuronal identity can lead to CHH phenotypes.
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Affiliation(s)
- Wilson CJ Chung
- Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Pei-San Tsai
- Department of Integrative Physiology, University of Colorado, Boulder, CO, United States
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3
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Han M, Liang C, Liu Y, He X, Chu M. Integrated Transcriptome Analysis Reveals the Crucial mRNAs and miRNAs Related to Fecundity in the Hypothalamus of Yunshang Black Goats during the Luteal Phase. Animals (Basel) 2022; 12:ani12233397. [PMID: 36496918 PMCID: PMC9738480 DOI: 10.3390/ani12233397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/27/2022] [Accepted: 11/30/2022] [Indexed: 12/07/2022] Open
Abstract
A normal estrus cycle is essential for the breeding of goats, and the luteal phase accounts for most of the estrus cycle. The corpus luteum (CL) formed during the luteal phase is a transient endocrine gland that is crucial for the reproductive cycle and pregnancy maintenance, and is controlled by many regulatory factors. However, the molecular mechanism of the hypothalamus effect on the reproductive performance of different litter sizes during the luteal phase of goats has not been elucidated. In this study, RNA-sequencing was used to analyze the mRNA and miRNA expression profiles of the hypothalamic tissues with the high-fecundity goats during the luteal phase (LP-HF) and low-fecundity goats during the luteal phase (LP-LF). The RNA-seq results found that there were 1963 differentially expressed genes (DEGs) (890 up-regulated and 1073 down-regulated). The miRNA-seq identified 57 differentially expressed miRNAs (DEMs), including 11 up-regulated and 46 down-regulated, of which 199 DEGs were predicted to be potential target genes of DEMs. Meanwhile, the functional enrichment analysis identified several mRNA-miRNA pairs involved in the regulation of the hypothalamic activity, such as the common target gene MEA1 of novel-miR-972, novel-miR-125 and novel-miR-403, which can play a certain role as a related gene of the reproductive development in the hypothalamic-pituitary-gonadal (HPG) axis and its regulated network, by regulating the androgen secretion. While another target gene ADIPOR2 of the novel-miR-403, is distributed in the hypothalamus and affects the reproductive system through a central role on the HPG axis and a peripheral role in the gonadal tissue. An annotation analysis of the DE miRNA-mRNA pairs identified targets related to biological processes, such as anion binding (GO:0043168) and small molecule binding (GO: 0036094). Subsequently, the KEGG(Kyoto Encyclopedia of Genes and Genomes) pathways were performed to analyze the miRNA-mRNA pairs with negatively correlated miRNAs. We found that the GnRH signaling pathway (ko04912), the estrogen signaling pathway (ko04915), the Fc gamma R-mediated phagocytosis (ko04666), and the IL-17 signaling pathway (ko04657), etc., were directly and indirectly associated with the reproductive process. These targeting interactions may be closely related to the reproductive performance of goats. The results of this study provide a reference for further research on the molecular regulation mechanism for the high fertility in goats.
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Affiliation(s)
- Miaoceng Han
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- College of Animal Science, Shanxi Agricultural University, Jinzhong 030801, China
| | - Chen Liang
- College of Animal Science, Shanxi Agricultural University, Jinzhong 030801, China
| | - Yufang Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaoyun He
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Mingxing Chu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Correspondence: ; Tel.: +86-010-62819850
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4
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Oleari R, Massa V, Cariboni A, Lettieri A. The Differential Roles for Neurodevelopmental and Neuroendocrine Genes in Shaping GnRH Neuron Physiology and Deficiency. Int J Mol Sci 2021; 22:9425. [PMID: 34502334 PMCID: PMC8431607 DOI: 10.3390/ijms22179425] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 01/19/2023] Open
Abstract
Gonadotropin releasing hormone (GnRH) neurons are hypothalamic neuroendocrine cells that control sexual reproduction. During embryonic development, GnRH neurons migrate from the nose to the hypothalamus, where they receive inputs from several afferent neurons, following the axonal scaffold patterned by nasal nerves. Each step of GnRH neuron development depends on the orchestrated action of several molecules exerting specific biological functions. Mutations in genes encoding for these essential molecules may cause Congenital Hypogonadotropic Hypogonadism (CHH), a rare disorder characterized by GnRH deficiency, delayed puberty and infertility. Depending on their action in the GnRH neuronal system, CHH causative genes can be divided into neurodevelopmental and neuroendocrine genes. The CHH genetic complexity, combined with multiple inheritance patterns, results in an extreme phenotypic variability of CHH patients. In this review, we aim at providing a comprehensive and updated description of the genes thus far associated with CHH, by dissecting their biological relevance in the GnRH system and their functional relevance underlying CHH pathogenesis.
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Affiliation(s)
- Roberto Oleari
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milano, Italy;
| | - Valentina Massa
- Department of Health Sciences, University of Milan, 20142 Milano, Italy;
- CRC Aldo Ravelli for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, 20142 Milano, Italy
| | - Anna Cariboni
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milano, Italy;
| | - Antonella Lettieri
- Department of Health Sciences, University of Milan, 20142 Milano, Italy;
- CRC Aldo Ravelli for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, 20142 Milano, Italy
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5
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Dela Cruz C, Horton CA, Sanders KN, Andersen ND, Tsai PS. Conditional Fgfr1 Deletion in GnRH Neurons Leads to Minor Disruptions in the Reproductive Axis of Male and Female Mice. Front Endocrinol (Lausanne) 2021; 11:588459. [PMID: 33679600 PMCID: PMC7933197 DOI: 10.3389/fendo.2020.588459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
In humans and mice, inactivating mutations in fibroblast growth factor receptor 1 (Fgfr1) lead to gonadotropin-releasing hormone (GnRH) deficiency and a host of downstream reproductive disorders. It was unclear if Fgfr1 signaling directly upon GnRH neurons critically drove the establishment of a functional GnRH system. To answer this question, we generated a mouse model with a conditional deletion of Fgfr1 in GnRH neurons using the Cre/loxP approach. These mice, called Fgfr1cKO mice, were examined along with control mice for their pubertal onset and a host of reproductive axis functions. Our results showed that Fgfr1cKO mice harbored no detectable defects in the GnRH system and pubertal onset, suffered only subtle changes in the pituitary function, but exhibited significantly disrupted testicular and ovarian morphology at 25 days of age, indicating impaired gametogenesis at a young age. However, these disruptions were transient and became undetectable in older mice. Our results suggest that Fgfr1 signaling directly on GnRH neurons supports, to some extent, the reproductive axis function in the period leading to the early phase of puberty, but is not critically required for pubertal onset or reproductive maintenance in sexually mature animals.
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Affiliation(s)
| | | | | | | | - Pei-San Tsai
- Department of Integrative Physiology, University of Colorado, Boulder, CO, United States
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6
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Erbaş İM, Paketçi A, Acar S, Kotan LD, Demir K, Abacı A, Böber E. A nonsense variant in FGFR1: a rare cause of combined pituitary hormone deficiency. J Pediatr Endocrinol Metab 2020; 33:1613-1615. [PMID: 32853167 DOI: 10.1515/jpem-2020-0029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/23/2020] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Variants in fibroblast growth factor receptor-1 (FGFR1) may either cause isolated hypogonadotropic hypogonadism (IHH) or Kallmann syndrome (KS). Although the relationship of genes classically involved in IHH with combined pituitary hormone deficiency (CPHD) is well established, variants in FGFR1 have been presented as a rare cause of this phenotype recently. CASE PRESENTATION Herein, we report an adopted 16-year-old male presented with delayed puberty and micropenis. He had undergone surgery for bilateral undescended testes in childhood. He was normosmic, and the pituitary imaging was normal. However, hypogonadotropic hypogonadism and growth hormone deficiency were detected, associated with a heterozygous nonsense variant (c.1864 C>T, p.R622X) in FGFR1. CONCLUSIONS FGFR1 variants are among the causes of IHH and KS, which are inherited in an autosomal dominant manner and can be associated with midline defects. It should also be kept in mind that CPHD may be associated with FGFR1 variants in a subject with normal olfactory function.
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Affiliation(s)
- İbrahim Mert Erbaş
- Department of Pediatric Endocrinology, Dokuz Eylül University Faculty of Medicine, İzmir, Turkey
| | - Ahu Paketçi
- Department of Pediatric Endocrinology, Dokuz Eylül University Faculty of Medicine, İzmir, Turkey
| | - Sezer Acar
- Department of Pediatric Endocrinology, Dokuz Eylül University Faculty of Medicine, İzmir, Turkey
| | - Leman Damla Kotan
- Department of Pediatric Endocrinology, Çukurova University Faculty of Medicine, Adana, Turkey
| | - Korcan Demir
- Department of Pediatric Endocrinology, Dokuz Eylül University Faculty of Medicine, İzmir, Turkey
| | - Ayhan Abacı
- Department of Pediatric Endocrinology, Dokuz Eylül University Faculty of Medicine, İzmir, Turkey
| | - Ece Böber
- Department of Pediatric Endocrinology, Dokuz Eylül University Faculty of Medicine, İzmir, Turkey
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7
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Posttranslational Modification Defects in Fibroblast Growth Factor Receptor 1 as a Reason for Normosmic Isolated Hypogonadotropic Hypogonadism. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:2358719. [PMID: 33299522 PMCID: PMC7704206 DOI: 10.1155/2020/2358719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/07/2020] [Accepted: 11/06/2020] [Indexed: 12/24/2022]
Abstract
Some mutations in FGFR1 affect the sense of smell while others do not, resulting in Kallmann syndrome (KS) and normosmic isolated hypogonadotropic hypogonadism (nIHH), respectively. The underlying mechanism is still unclear. FGFR1 variants are found in less than 10% of patients with KS and nIHH, and among them, only some have undergone functional analysis. Thus, the correlation between the phenotype and genotype cannot be clearly verified. This study reports a case of nIHH and explores the potential mechanism of the FGFR1 gene in the pathogenesis of nIHH. A preschooler with cryptorchidism, micropenis, strabismus, and hypopsia is described. As he had a normal sense of smell, he was diagnosed with nIHH. A de novo mutation in FGFR1 (c.2008G>A) was detected in the patient along with a novel variant in CEP290 (c.964G>A) inherited from his mother. We present compelling in vitro evidence that this FGFR1 mutation-induced posttranslational modification defect, including defective glycosylation and impaired trans-autophosphorylation, along with the final reduction in expression, could lead to impairment of the receptor and abnormal signaling and eventually result in developmental abnormalities and inhibition of GnRH neuron release. The identification of an additional variant suggests that CEP290 might play a potential role in GnRH development.
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8
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Does the Act of Copulation per se, without Considering Seminal Deposition, Change the Expression of Genes in the Porcine Female Genital Tract? Int J Mol Sci 2020; 21:ijms21155477. [PMID: 32751869 PMCID: PMC7432858 DOI: 10.3390/ijms21155477] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 07/29/2020] [Indexed: 02/07/2023] Open
Abstract
Semen—through its specific sperm and seminal plasma (SP) constituents—induces changes of gene expression in the internal genital tract of pigs, particularly in the functional sperm reservoir at the utero-tubal junction (UTJ). Although seminal effects are similarly elicited by artificial insemination (AI), major changes in gene expression are registered after natural mating, a fact suggesting the act of copulation induces per se changes in genes that AI does not affect. The present study explored which pathways were solely influenced by copulation, affecting the differential expression of genes (DEGs) of the pre/peri-ovulatory genital tract (cervix, distal uterus, proximal uterus and UTJ) of estrus sows, 24 h after various procedures were performed to compare natural mating with AI of semen (control 1), sperm-free SP harvested from the sperm-peak fraction (control 2), sperm-free SP harvested from the whole ejaculate (control 3) or saline-extender BTS (control 4), using a microarray chip (GeneChip® porcine gene 1.0 st array). Genes related to neuroendocrine responses (ADRA1, ADRA2, GABRB2, CACNB2), smooth muscle contractility (WNT7A), angiogenesis and vascular remodeling (poFUT1, NTN4) were, among others, overrepresented with distal and proximal uterine segments exhibiting the highest number of DEGs. The findings provide novel evidence that relevant transcriptomic changes in the porcine female reproductive tract occur in direct response to the specific act of copulation, being semen-independent.
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9
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Duan C, Allard J. Gonadotropin-releasing hormone neuron development in vertebrates. Gen Comp Endocrinol 2020; 292:113465. [PMID: 32184073 DOI: 10.1016/j.ygcen.2020.113465] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/26/2020] [Accepted: 03/12/2020] [Indexed: 11/21/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) neurons are master regulators of the reproductive axis in vertebrates. During early mammalian embryogenesis, GnRH1 neurons emerge in the nasal/olfactory placode. These neurons undertake a long-distance migration, moving from the nose to the preoptic area and hypothalamus. While significant advances have been made in understanding the functional importance of the GnRH1 neurons in reproduction, where GnRH1 neurons come from and how are they specified during early development is still under debate. In addition to the GnRH1 gene, most vertebrate species including humans have one or two additional GnRH genes. Compared to the GnRH1 neurons, much less is known about the development and regulation of GnRH2 neuron and GnRH3 neurons. The objective of this article is to review what is currently known about GnRH neuron development. We will survey various cell autonomous and non-autonomous factors implicated in the regulation of GnRH neuron development. Finally, we will discuss emerging tools and new approaches to resolve open questions pertaining to GnRH neuron development.
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Affiliation(s)
- Cunming Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States.
| | - John Allard
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States
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10
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Linscott ML, Chung WCJ. Epigenomic control of gonadotrophin-releasing hormone neurone development and hypogonadotrophic hypogonadism. J Neuroendocrinol 2020; 32:e12860. [PMID: 32452569 DOI: 10.1111/jne.12860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 04/24/2020] [Accepted: 05/01/2020] [Indexed: 11/30/2022]
Abstract
Mammalian reproductive success depends on gonadotrophin-releasing hormone (GnRH) neurones to stimulate gonadotrophin secretion from the anterior pituitary and activate gonadal steroidogenesis and gametogenesis. Genetic screening studies in patients diagnosed with Kallmann syndrome (KS), a congenital form of hypogonadotrophic hypogonadism (CHH), identified several causal mutations, including those in the fibroblast growth factor (FGF) system. This signalling pathway regulates neuroendocrine progenitor cell proliferation, fate specification and cell survival. Indeed, the GnRH neurone system was absent or abrogated in transgenic mice with reduced (ie, hypomorphic) Fgf8 and/or Fgf receptor (Fgfr) 1 expression, respectively. Moreover, we found that GnRH neurones were absent in the embryonic olfactory placode of Fgf8 hypomorphic mice, the putative birthplace of GnRH neurones. These observations, together with those made in human KS/CHH patients, indicate that the FGF8/FGFR1 signalling system is a requirement for the ontogenesis of the GnRH neuronal system and function. In this review, we discuss how epigenetic factors control the expression of genes such as Fgf8 that are known to be critical for GnRH neurone ontogenesis, fate specification, and the pathogenesis of KS/CHH.
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Affiliation(s)
- Megan L Linscott
- Department of Biological Sciences, Kent State University, Kent, OH, USA
- Brain Health Research Institute, Kent State University, Kent, OH, USA
| | - Wilson C J Chung
- Department of Biological Sciences, Kent State University, Kent, OH, USA
- Brain Health Research Institute, Kent State University, Kent, OH, USA
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
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11
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Li S, Zhao Y, Nie M, Ma W, Wang X, Ji W, Yang Y, Hao M, Yu B, Gao Y, Mao J, Wu X. Clinical Characteristics and Spermatogenesis in Patients with Congenital Hypogonadotropic Hypogonadism Caused by FGFR1 Mutations. Int J Endocrinol 2020; 2020:8873532. [PMID: 33354214 PMCID: PMC7737440 DOI: 10.1155/2020/8873532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/30/2020] [Accepted: 11/05/2020] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVE The aim of this study was to investigate the clinical characteristics of patients diagnosed with congenital hypogonadotropic hypogonadism (CHH) caused by FGFR1 (fibroblast growth factor receptor 1) gene mutations and to evaluate the effect of gonadotropin or pulsatile gonadotropin-releasing hormone (GnRH) therapy on spermatogenesis. METHODS A retrospective study was conducted on CHH patients admitted to Peking Union Medical College Hospital from January 2012 to March 2020. Clinical features and laboratory results were recorded. Testicular volume and sperm count responding to gonadotropin and pulsatile GnRH therapy were compared between the FGFR1 mutation group and the mutation-negative group. RESULTS (1) FGFR1 mutation group included 14 patients who received sperm-induction therapy, and the mutation-negative group enrolled 25 CHH patients. (2) The incidence of cryptorchidism was 50.0% (7/14) and 12.0% (3/25) in the FGFR1 group and the mutation-negative group, respectively (p=0.019). The baseline testicular volume of the FGFR1 mutation group was smaller than that of the mutation-negative group, 1.6 (0.5-2.0) mL vs. 2 (1.75-4) mL (p=0.033). The baseline luteinizing hormone (LH), Follicle-stimulating hormone (FSH), and testosterone levels were similar between the two groups. (3) Using the Kaplan-Meier and log-rank tests for the analysis of spermatogenesis, it was found that there was no significant difference in the first sperm appearance between the FGFR1 mutation group and the mutation-negative group (χ 2 = 1.974, p=0.160). The median time of spermatogenesis in the FGFR1 mutation group was longer than that in the mutation-negative group, 16 months vs. 10 months, respectively. The cumulative spermatogenesis success rate at 12 months in the FGFR1 mutation group (35.71%) was lower than that in the mutation-negative group (68.75%) (p=0.047). The sperm concentration in the mutation-negative group was more easily achieved for different thresholds compared with that in the FGFR1 mutation group, but no significant difference was observed (p > 0.05) between the two groups. The last follow-up examination showed that the testicular volume was 7.00 (4.75-12.00) mL and 10.56 ± 4.82 mL (p=0.098), the ejaculate volume of sperm was 2.20 (1.40-2.26) mL and 3.06 ± 1.42 mL (p=0.175), and the sperm concentration was 7.19 (1.00-9.91) million/mL and 18.80 (4.58-53.62) million/mL (p=0.038) in the FGFR1 mutation and mutation-negative groups, respectively, while the sperm motility (A%, A + B%, and A + B + C%) was similar for the two groups (p=0.839, 0.909, and 0.759, respectively). The testosterone level during treatment was 366.02 ± 167.03 ng/dL and 362.27 ± 212.86 ng/dL in the FGFR1 mutation and mutation-negative groups, respectively (p=0.956). CONCLUSION Patients with FGFR1 mutations have a higher prevalence of cryptorchidism and smaller testicular volume. Although patients with FGFR1 mutations have a similar rate of success for spermatogenesis compared to that of the mutation-negative patients, a longer treatment period was required and a lower sperm concentration was achieved.
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Affiliation(s)
- Shuying Li
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yaling Zhao
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Min Nie
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Wanlu Ma
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xi Wang
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Wen Ji
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yufan Yang
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Ming Hao
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Bingqing Yu
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yinjie Gao
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Jiangfeng Mao
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xueyan Wu
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
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12
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Pandolfi EC, Tonsfeldt KJ, Hoffmann HM, Mellon PL. Deletion of the Homeodomain Protein Six6 From GnRH Neurons Decreases GnRH Gene Expression, Resulting in Infertility. Endocrinology 2019; 160:2151-2164. [PMID: 31211355 PMCID: PMC6821215 DOI: 10.1210/en.2019-00113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 06/11/2019] [Indexed: 12/12/2022]
Abstract
Hypothalamic GnRH (luteinizing hormone-releasing hormone) neurons are crucial for the hypothalamic-pituitary-gonadal (HPG) axis, which regulates mammalian fertility. Insufficient GnRH disrupts the HPG axis and is often associated with the genetic condition idiopathic hypogonadotropic hypogonadism (IHH). The homeodomain protein sine oculis-related homeobox 6 (Six6) is required for the development of GnRH neurons. Although it is known that Six6 is specifically expressed within a more mature GnRH neuronal cell line and that overexpression of Six6 induces GnRH transcription in these cells, the direct role of Six6 within the GnRH neuron in vivo is unknown. Here we find that global Six6 knockout (KO) embryos show apoptosis of GnRH neurons beginning at embryonic day 14.5 with 90% loss of GnRH neurons by postnatal day 1. We sought to determine whether the hypogonadism and infertility reported in the Six6KO mice are generated via actions within the GnRH neuron in vivo by creating a Six6-flox mouse and crossing it with the LHRHcre mouse. Loss of Six6 specifically within the GnRH neuron abolished GnRH expression in ∼0% of GnRH neurons. We further demonstrated that deletion of Six6 only within the GnRH neuron leads to infertility, hypogonadism, hypogonadotropism, and delayed puberty. We conclude that Six6 plays distinct roles in maintaining fertility in the GnRH neuron vs in the migratory environment of the GnRH neuron by maintaining expression of GnRH and survival of GnRH neurons, respectively. These results increase knowledge of the role of Six6 in the brain and may offer insight into the mechanism of IHH.
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Affiliation(s)
- Erica C Pandolfi
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
| | - Karen J Tonsfeldt
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
| | - Hanne M Hoffmann
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
- Department of Animal Science, Michigan State University, East Lansing, Michigan
| | - Pamela L Mellon
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California
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13
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Xu C, Messina A, Somm E, Miraoui H, Kinnunen T, Acierno J, Niederländer NJ, Bouilly J, Dwyer AA, Sidis Y, Cassatella D, Sykiotis GP, Quinton R, De Geyter C, Dirlewanger M, Schwitzgebel V, Cole TR, Toogood AA, Kirk JM, Plummer L, Albrecht U, Crowley WF, Mohammadi M, Tena-Sempere M, Prevot V, Pitteloud N. KLB, encoding β-Klotho, is mutated in patients with congenital hypogonadotropic hypogonadism. EMBO Mol Med 2018; 9:1379-1397. [PMID: 28754744 PMCID: PMC5623842 DOI: 10.15252/emmm.201607376] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic form of isolated gonadotropin‐releasing hormone (GnRH) deficiency caused by mutations in > 30 genes. Fibroblast growth factor receptor 1 (FGFR1) is the most frequently mutated gene in CHH and is implicated in GnRH neuron development and maintenance. We note that a CHH FGFR1 mutation (p.L342S) decreases signaling of the metabolic regulator FGF21 by impairing the association of FGFR1 with β‐Klotho (KLB), the obligate co‐receptor for FGF21. We thus hypothesized that the metabolic FGF21/KLB/FGFR1 pathway is involved in CHH. Genetic screening of 334 CHH patients identified seven heterozygous loss‐of‐function KLB mutations in 13 patients (4%). Most patients with KLB mutations (9/13) exhibited metabolic defects. In mice, lack of Klb led to delayed puberty, altered estrous cyclicity, and subfertility due to a hypothalamic defect associated with inability of GnRH neurons to release GnRH in response to FGF21. Peripheral FGF21 administration could indeed reach GnRH neurons through circumventricular organs in the hypothalamus. We conclude that FGF21/KLB/FGFR1 signaling plays an essential role in GnRH biology, potentially linking metabolism with reproduction.
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Affiliation(s)
- Cheng Xu
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Andrea Messina
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Emmanuel Somm
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Hichem Miraoui
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Tarja Kinnunen
- Department of Biology, School of Applied Sciences, University of Huddersfield, Huddersfield, UK
| | - James Acierno
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Nicolas J Niederländer
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Justine Bouilly
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Andrew A Dwyer
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland.,University of Lausanne Institute of Higher Education and Research in Healthcare, Lausanne, Switzerland
| | - Yisrael Sidis
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Daniele Cassatella
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Gerasimos P Sykiotis
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
| | - Richard Quinton
- Institute for Genetic Medicine, University of Newcastle-on-Tyne, Newcastle-on Tyne, UK
| | - Christian De Geyter
- Clinic of Gynecological Endocrinology and Reproductive Medicine, University Hospital, University of Basel, Basel, Switzerland
| | - Mirjam Dirlewanger
- Pediatric Endocrine and Diabetes Unit, Children's Hospital, University Hospitals and Faculty of Medicine, Geneva, Switzerland
| | - Valérie Schwitzgebel
- Pediatric Endocrine and Diabetes Unit, Children's Hospital, University Hospitals and Faculty of Medicine, Geneva, Switzerland
| | - Trevor R Cole
- Department of Clinical Genetics, Birmingham Women's Hospital, Birmingham, UK
| | - Andrew A Toogood
- Department of Endocrinology, Queen Elizabeth Hospital, University Hospitals Birmingham, Birmingham, UK
| | - Jeremy Mw Kirk
- Department of Endocrinology, Birmingham Children's Hospital, Birmingham, UK
| | - Lacey Plummer
- National Center for Translational Research in Reproduction and Infertility, Harvard Reproductive Endocrine Sciences Center of the Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Urs Albrecht
- Department of Biology, Biochemistry, Faculty of Science, University of Fribourg, Fribourg, Switzerland
| | - William F Crowley
- National Center for Translational Research in Reproduction and Infertility, Harvard Reproductive Endocrine Sciences Center of the Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Moosa Mohammadi
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Manuel Tena-Sempere
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain.,Instituto Maimonides de Investigación Biomédica de Cordoba (IMIBIC/HURS), Cordoba, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Cordoba, Spain
| | - Vincent Prevot
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, JPARC, Lille, France.,FHU 1000 Days for Health, School of Medicine, University of Lille, Lille, France
| | - Nelly Pitteloud
- Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland
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Luo H, Zheng R, Zhao Y, Wu J, Li J, Jiang F, Chen DN, Zhou XT, Li JD. A dominant negative FGFR1 mutation identified in a Kallmann syndrome patient. Gene 2017; 621:1-4. [DOI: 10.1016/j.gene.2017.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/24/2017] [Accepted: 04/10/2017] [Indexed: 02/07/2023]
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Abstract
The fibroblast growth factor (Fgf) family of ligands and receptor tyrosine kinases is required throughout embryonic and postnatal development and also regulates multiple homeostatic functions in the adult. Here, Brewer et al. review the mechanisms of Fgf signaling by focusing on genetic strategies that enable in vivo analysis. The fibroblast growth factor (Fgf) family of ligands and receptor tyrosine kinases is required throughout embryonic and postnatal development and also regulates multiple homeostatic functions in the adult. Aberrant Fgf signaling causes many congenital disorders and underlies multiple forms of cancer. Understanding the mechanisms that govern Fgf signaling is therefore important to appreciate many aspects of Fgf biology and disease. Here we review the mechanisms of Fgf signaling by focusing on genetic strategies that enable in vivo analysis. These studies support an important role for Erk1/2 as a mediator of Fgf signaling in many biological processes but have also provided strong evidence for additional signaling pathways in transmitting Fgf signaling in vivo.
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Affiliation(s)
- J Richard Brewer
- Department of Developmental and Regenerative Biology, Tisch Cancer Institute, Icahn School of Medicine at Mt. Sinai, New York, New York 10029, USA
| | - Pierre Mazot
- Department of Developmental and Regenerative Biology, Tisch Cancer Institute, Icahn School of Medicine at Mt. Sinai, New York, New York 10029, USA
| | - Philippe Soriano
- Department of Developmental and Regenerative Biology, Tisch Cancer Institute, Icahn School of Medicine at Mt. Sinai, New York, New York 10029, USA
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16
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Huilgol D, Tole S. Cell migration in the developing rodent olfactory system. Cell Mol Life Sci 2016; 73:2467-90. [PMID: 26994098 PMCID: PMC4894936 DOI: 10.1007/s00018-016-2172-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 02/08/2016] [Accepted: 03/01/2016] [Indexed: 02/06/2023]
Abstract
The components of the nervous system are assembled in development by the process of cell migration. Although the principles of cell migration are conserved throughout the brain, different subsystems may predominantly utilize specific migratory mechanisms, or may display unusual features during migration. Examining these subsystems offers not only the potential for insights into the development of the system, but may also help in understanding disorders arising from aberrant cell migration. The olfactory system is an ancient sensory circuit that is essential for the survival and reproduction of a species. The organization of this circuit displays many evolutionarily conserved features in vertebrates, including molecular mechanisms and complex migratory pathways. In this review, we describe the elaborate migrations that populate each component of the olfactory system in rodents and compare them with those described in the well-studied neocortex. Understanding how the components of the olfactory system are assembled will not only shed light on the etiology of olfactory and sexual disorders, but will also offer insights into how conserved migratory mechanisms may have shaped the evolution of the brain.
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Affiliation(s)
- Dhananjay Huilgol
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
- Cold Spring Harbor Laboratory, Cold Spring Harbor, USA
| | - Shubha Tole
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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17
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Regulation of FGF signaling: Recent insights from studying positive and negative modulators. Semin Cell Dev Biol 2016; 53:101-14. [DOI: 10.1016/j.semcdb.2016.01.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/19/2016] [Indexed: 11/19/2022]
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18
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Chung WCJ, Linscott ML, Rodriguez KM, Stewart CE. The Regulation and Function of Fibroblast Growth Factor 8 and Its Function during Gonadotropin-Releasing Hormone Neuron Development. Front Endocrinol (Lausanne) 2016; 7:114. [PMID: 27656162 PMCID: PMC5011149 DOI: 10.3389/fendo.2016.00114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 08/08/2016] [Indexed: 11/13/2022] Open
Abstract
Over the last few years, numerous studies solidified the hypothesis that fibroblast growth factor (FGF) signaling regulates neuroendocrine progenitor cell proliferation, fate specification, and cell survival and, therefore, is critical for the regulation and maintenance of homeostasis of the body. One important example that underscores the involvement of FGF signaling during neuroendocrine cell development is gonadotropin-releasing hormone (GnRH) neuron ontogenesis. Indeed, transgenic mice with reduced olfactory placode (OP) Fgf8 expression do not have GnRH neurons. This observation indicates the requirement of FGF8 signaling for the emergence of the GnRH neuronal system in the embryonic OP, the putative birth place of GnRH neurons. Mammalian reproductive success depends on the presence of GnRH neurons to stimulate gonadotropin secretion from the anterior pituitary, which activates gonadal steroidogenesis and gametogenesis. Together, these observations are critical for understanding the function of GnRH neurons and their control of the hypothalamus-pituitary-gonadal (HPG) axis to maintain fertility. Taken together, these studies illustrate that GnRH neuron emergence and hence HPG function is vulnerable to genomic and molecular signals that abnormally modify Fgf8 expression in the developing mouse OP. In this short review, we focus on research that is aimed at unraveling how androgen, all-trans retinoic acid, and how epigenetic factors modify control mouse OP Fgf8 transcription in the context of GnRH neuronal development and mammalian reproductive success.
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Affiliation(s)
- Wilson C. J. Chung
- Department of Biological Sciences, School of Biomedical Sciences, Kent State University, Kent, OH, USA
- *Correspondence: Wilson C. J. Chung,
| | - Megan L. Linscott
- Department of Biological Sciences, School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Karla M. Rodriguez
- Department of Biological Sciences, School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Courtney E. Stewart
- Department of Biological Sciences, School of Biomedical Sciences, Kent State University, Kent, OH, USA
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19
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Herde MK, Herbison AE. Morphological Characterization of the Action Potential Initiation Segment in GnRH Neuron Dendrites and Axons of Male Mice. Endocrinology 2015; 156:4174-86. [PMID: 26267379 DOI: 10.1210/en.2015-1284] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GnRH neurons are the final output neurons of the hypothalamic network controlling fertility in mammals. In the present study, we used ankyrin G immunohistochemistry and neurobiotin filling of live GnRH neurons in brain slices from GnRH-green fluorescent protein transgenic male mice to examine in detail the location of action potential initiation in GnRH neurons with somata residing at different locations in the basal forebrain. We found that the vast majority of GnRH neurons are bipolar in morphology, elaborating a thick (primary) and thinner (secondary) dendrite from opposite poles of the soma. In addition, an axon-like process arising predominantly from a proximal dendrite was observed in a subpopulation of GnRH neurons. Ankyrin G immunohistochemistry revealed the presence of a single action potential initiation zone ∼27 μm in length primarily in the secondary dendrite of GnRH neurons and located 30 to 140 μm distant from the cell soma, depending on the type of process and location of the cell body. In addition to dendrites, the GnRH neurons with cell bodies located close to hypothalamic circumventricular organs often elaborated ankyrin G-positive axon-like structures. Almost all GnRH neurons (>90%) had their action potential initiation site in a process that initially, or ultimately after a hairpin loop, was coursing in the direction of the median eminence. These studies indicate that action potentials are initiated in different dendritic and axonal compartments of the GnRH neuron in a manner that is dependent partly on the neuroanatomical location of the cell body.
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Affiliation(s)
- Michel K Herde
- Centre for Neuroendocrinology and Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Allan E Herbison
- Centre for Neuroendocrinology and Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand
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20
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Quaynor SD, Ko EK, Chorich LP, Sullivan ME, Demir D, Waller JL, Kim HG, Cameron RS, Layman LC. NELF knockout is associated with impaired pubertal development and subfertility. Mol Cell Endocrinol 2015; 407:26-36. [PMID: 25731822 PMCID: PMC4429764 DOI: 10.1016/j.mce.2015.02.015] [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] [Received: 11/05/2014] [Revised: 02/14/2015] [Accepted: 02/14/2015] [Indexed: 11/17/2022]
Abstract
Puberty and reproduction require proper signaling of the hypothalamic-pituitary-gonadal axis controlled by gonadotropin-releasing hormone (GnRH) neurons, which arise in the olfactory placode region and migrate along olfactory axons to the hypothalamus. Factors adversely affecting GnRH neuron specification, migration, and function lead to delayed puberty and infertility. Nasal embryonic luteinizing hormone-releasing factor (NELF) is a predominantly nuclear protein. NELF mutations have been demonstrated in patients with hypogonadotropic hypogonadism, but biallelic mutations are rare and heterozygous NELF mutations typically co-exist with mutations in another gene. Our previous studies in immortalized GnRH neurons supported a role for NELF in GnRH neuron migration. To better understand the physiology of NELF, a homozygous Nelf knockout (KO) mouse model was generated. Our findings indicate that female Nelf KO mice have delayed vaginal opening but no delay in time to first estrus, decreased uterine weight, and reduced GnRH neuron number. In contrast, male mice were normal at puberty. Both sexes of mice had impaired fertility manifested as reduced mean litter size. These data support that NELF has important reproductive functions. The milder than expected phenotype of KO mice also recapitulates the human phenotype since heterozygous NELF mutations usually require an additional mutation in a second gene to result in hypogonadotropic hypogonadism.
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Affiliation(s)
- Samuel D Quaynor
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Department of Physiology; Georgia Regents University, Augusta, GA 30912, USA
| | - Eun Kyung Ko
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Department of Physiology; Georgia Regents University, Augusta, GA 30912, USA
| | - Lynn P Chorich
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Department of Physiology; Georgia Regents University, Augusta, GA 30912, USA
| | - Megan E Sullivan
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Department of Physiology; Georgia Regents University, Augusta, GA 30912, USA
| | - Durkadin Demir
- Department of Medical Biology and Genetics, Akdeniz University, Antalya 07058, Turkey
| | - Jennifer L Waller
- Department of Biostatistics & Epidemiology, Georgia Regents University, Augusta, GA 30912, USA
| | - Hyung-Goo Kim
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Department of Physiology; Georgia Regents University, Augusta, GA 30912, USA; Department of Neuroscience and Regenerative Medicine, Georgia Regents University, Augusta, GA 30912, USA
| | - Richard S Cameron
- Department of Medicine, Georgia Regents University, Augusta, GA 30912, USA; Department of Neuroscience and Regenerative Medicine, Georgia Regents University, Augusta, GA 30912, USA
| | - Lawrence C Layman
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Department of Physiology; Georgia Regents University, Augusta, GA 30912, USA; Department of Neuroscience and Regenerative Medicine, Georgia Regents University, Augusta, GA 30912, USA; Department of Physiology, Georgia Regents University, Augusta, GA 30912, USA.
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21
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Zhang W, Johnson JI, Tsai PS. Fgf8-Deficient Mice Compensate for Reduced GnRH Neuronal Population and Exhibit Normal Testicular Function. Front Endocrinol (Lausanne) 2015; 6:151. [PMID: 26441841 PMCID: PMC4585285 DOI: 10.3389/fendo.2015.00151] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 09/07/2015] [Indexed: 11/13/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is critical for the onset and maintenance of reproduction in vertebrates. The development of GnRH neurons is highly dependent on fibroblast growth factor (Fgf) signaling. Mice with a hypomorphic Fgf8 allele (Fgf8 Het) exhibited a ~50% reduction in GnRH neuron number at birth. Female Fgf8 Het mice were fertile but showed significantly delayed puberty. However, it was unclear if these mice suffered additional loss of GnRH neurons after birth, and if male Fgf8 Het mice had normal pubertal transition and testicular function. In this study, we examined postnatal GnRH neuron number and hypothalamic GnRH content in Fgf8 Het mice from birth to 120 days of age. Further, we examined seminal vesicle and testicular growth, testicular histology, and circulating luteinizing hormone (LH) around and after pubertal transition. Our results showed that GnRH neuron numbers were significantly and consistently reduced in Fgf8 Het mice of both sexes in all ages examined, suggesting these animals were born with an inherently defective GnRH system, and no further postnatal loss of GnRH neurons had occurred. Despite an innately compromised GnRH system, male and female Fgf8 mice exhibited normal levels of immunoassayable hypothalamic GnRH peptide at all ages examined except on 60 days of age, suggesting increased GnRH synthesis or reduced turnover as a compensatory mechanism. Fgf8 Het males also had normal seminal vesicle and testicular mass/body mass ratios, testicular histology, and circulating LH. Overall, our data speak to the extraordinary ability of a GnRH system permanently compromised by developmental defect to overcome pre-existing deficiencies to ensure pubertal progression and reproduction.
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Affiliation(s)
- Wei Zhang
- Department of Integrative Physiology, Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA
| | - Joshua I. Johnson
- Department of Integrative Physiology, Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA
| | - Pei-San Tsai
- Department of Integrative Physiology, Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA
- *Correspondence: Pei-San Tsai, Department of Integrative Physiology, University of Colorado Boulder, 114 Clare Small, Boulder, CO 80309-0354, USA,
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22
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Congenital hypogonadotropic hypogonadism with split hand/foot malformation: a clinical entity with a high frequency of FGFR1 mutations. Genet Med 2014; 17:651-9. [PMID: 25394172 PMCID: PMC4430466 DOI: 10.1038/gim.2014.166] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 10/09/2014] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Congenital hypogonadotropic hypogonadism (CHH) and split hand/foot malformation (SHFM) are two rare genetic conditions. Here we report a clinical entity comprising the two. METHODS We identified patients with CHH and SHFM through international collaboration. Probands and available family members underwent phenotyping and screening for FGFR1 mutations. The impact of identified mutations was assessed by sequence- and structure-based predictions and/or functional assays. RESULTS We identified eight probands with CHH with (n = 3; Kallmann syndrome) or without anosmia (n = 5) and SHFM, seven of whom (88%) harbor FGFR1 mutations. Of these seven, one individual is homozygous for p.V429E and six individuals are heterozygous for p.G348R, p.G485R, p.Q594*, p.E670A, p.V688L, or p.L712P. All mutations were predicted by in silico analysis to cause loss of function. Probands with FGFR1 mutations have severe gonadotropin-releasing hormone deficiency (absent puberty and/or cryptorchidism and/or micropenis). SHFM in both hands and feet was observed only in the patient with the homozygous p.V429E mutation; V429 maps to the fibroblast growth factor receptor substrate 2α binding domain of FGFR1, and functional studies of the p.V429E mutation demonstrated that it decreased recruitment and phosphorylation of fibroblast growth factor receptor substrate 2α to FGFR1, thereby resulting in reduced mitogen-activated protein kinase signaling. CONCLUSION FGFR1 should be prioritized for genetic testing in patients with CHH and SHFM because the likelihood of a mutation increases from 10% in the general CHH population to 88% in these patients.
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23
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Kuo MW, Lou SW, Chung BC. Hedgehog-PKA signaling and gnrh3 regulate the development of zebrafish gnrh3 neurons. PLoS One 2014; 9:e95545. [PMID: 24879419 PMCID: PMC4039432 DOI: 10.1371/journal.pone.0095545] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 03/28/2014] [Indexed: 01/21/2023] Open
Abstract
GnRH neurons secrete GnRH that controls the development of the reproduction system. Despite many studies, the signals controlling the development of GnRH neurons from its progenitors have not been fully established. To understand the development of GnRH neurons, we examined the development of gnrh3-expressing cells using a transgenic zebrafish line that expresses green fluorescent protein (GFP) and LacZ driven by the gnrh3 promoter. GFP and LacZ expression recapitulated that of gnrh3 in the olfactory region, olfactory bulb and telencephalon. Depletion of gnrh3 by morpholinos led to a reduction of GFP- and gnrh3-expressing cells, while over-expression of gnrh3 mRNA increased the number of these cells. This result indicates a positive feed-forward regulation of gnrh3 cells by gnrh3. The gnrh3 cells were absent in embryos that lack Hedgehog signaling, but their numbers were increased in embryos overexpressing shhb. We manipulated the amounts of kinase that antagonizes the Hedgehog signaling pathway, protein kinase A (PKA), by treating embryos with PKA activator forskolin or by injecting mRNAs encoding its constitutively active catalytic subunit (PKA*) and dominant negative regulatory subunit (PKI) into zebrafish embryos. PKA* misexpression or forskolin treatment decreased GFP cell numbers, while PKI misexpression led to ectopic production of GFP cells. Our data indicate that the Hedgehog-PKA pathway participates in the development of gnrh3-expressing neurons during embryogenesis.
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Affiliation(s)
- Ming-Wei Kuo
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Institute of Fisheries Science, National Taiwan University, Taipei, Taiwan
| | - Show-Wan Lou
- Institute of Fisheries Science, National Taiwan University, Taipei, Taiwan
| | - Bon-chu Chung
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail:
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24
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Jung LH, Kavanaugh SI, Sun B, Tsai PS. Localization of a molluscan gonadotropin-releasing hormone in Aplysia californica by in situ hybridization and immunocytochemistry. Gen Comp Endocrinol 2014; 195:132-7. [PMID: 24246309 DOI: 10.1016/j.ygcen.2013.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 11/05/2013] [Accepted: 11/06/2013] [Indexed: 11/16/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) plays important roles in vertebrate reproduction. Recently, molecules structurally similar to vertebrate GnRH were discovered in mollusks, including a gastropod, Aplysia californica. As an important step toward understanding the function of A. californica GnRH (ap-GnRH), the present study examined the localization of ap-GnRH peptide and transcript in the central and peripheral tissues. Reverse transcription polymerase chain reaction (RT-PCR) revealed wide expression of ap-GnRH in all ganglia (abdominal, buccal, cerebral, and pedal ganglia) of the central nervous system (CNS) and in multiple peripheral organs. However, in situ hybridization (ISH) revealed that cells positive for ap-GnRH are detectable only in the CNS, with the pedal ganglia containing the highest number of ap-GnRH-positive neurons, followed by the cerebral and abdominal ganglia. Most neurons positive for the transcript were simultaneously positive for the peptide, although some discrepancies were observed in cerebral and abdominal ganglia. Overall, our data suggest the de novo synthesis of ap-GnRH is restricted to the CNS, with the pedal ganglia being the primary source of ap-GnRH. Our results support the notion that ap-GnRH is a bona-fide neuropeptide that may assume diverse central functions, including those unrelated to reproduction.
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Affiliation(s)
- Lisa H Jung
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, United States
| | - Scott I Kavanaugh
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, United States
| | - Biao Sun
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, United States
| | - Pei-San Tsai
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, United States.
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Maternal dexamethasone exposure during pregnancy in rats disrupts gonadotropin-releasing hormone neuronal development in the offspring. Cell Tissue Res 2013; 355:409-23. [PMID: 24374911 PMCID: PMC3921457 DOI: 10.1007/s00441-013-1765-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/29/2013] [Indexed: 12/02/2022]
Abstract
The migration of gonadotropin-releasing hormone (GnRH) neurons from the olfactory placode to the preoptic area (POA) from embryonic day 13 is important for successful reproduction during adulthood. Whether maternal glucocorticoid exposure alters GnRH neuronal morphology and number in the offspring is unknown. This study determines the effect of maternal dexamethasone (DEX) exposure on enhanced green fluorescent protein (EGFP) driven by GnRH promoter neurons (TG-GnRH) in transgenic rats dual-labelled with GnRH immunofluorescence (IF-GnRH). The TG-GnRH neurons were examined in intact male and female rats at different postnatal ages, as a marker for GnRH promoter activity. Pregnant females were subcutaneously injected with DEX (0.1 mg/kg) or vehicle daily during gestation days 13–20 to examine the number of GnRH neurons in P0 male offspring. The total number of TG-GnRH neurons and TG-GnRH/IF-GnRH neuronal ratio increased from P0 and P5 stages to P47–52 stages, suggesting temporal regulation of GnRH promoter activity during postnatal development in intact rats. In DEX-treated P0 males, the number of IF-GnRH neurons decreased within the medial septum, organum vasculosom of the lamina terminalis (OVLT) and anterior hypothalamus. The percentage of TG-GnRH neurons with branched dendritic structures decreased in the OVLT of DEX-P0 males. These results suggest that maternal DEX exposure affects the number and dendritic development of early postnatal GnRH neurons in the OVLT/POA, which may lead to altered reproductive functions in adults.
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Miraoui H, Dwyer AA, Sykiotis GP, Plummer L, Chung W, Feng B, Beenken A, Clarke J, Pers TH, Dworzynski P, Keefe K, Niedziela M, Raivio T, Crowley WF, Seminara SB, Quinton R, Hughes VA, Kumanov P, Young J, Yialamas MA, Hall JE, Van Vliet G, Chanoine JP, Rubenstein J, Mohammadi M, Tsai PS, Sidis Y, Lage K, Pitteloud N. Mutations in FGF17, IL17RD, DUSP6, SPRY4, and FLRT3 are identified in individuals with congenital hypogonadotropic hypogonadism. Am J Hum Genet 2013; 92:725-43. [PMID: 23643382 DOI: 10.1016/j.ajhg.2013.04.008] [Citation(s) in RCA: 184] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 03/14/2013] [Accepted: 04/10/2013] [Indexed: 12/22/2022] Open
Abstract
Congenital hypogonadotropic hypogonadism (CHH) and its anosmia-associated form (Kallmann syndrome [KS]) are genetically heterogeneous. Among the >15 genes implicated in these conditions, mutations in FGF8 and FGFR1 account for ~12% of cases; notably, KAL1 and HS6ST1 are also involved in FGFR1 signaling and can be mutated in CHH. We therefore hypothesized that mutations in genes encoding a broader range of modulators of the FGFR1 pathway might contribute to the genetics of CHH as causal or modifier mutations. Thus, we aimed to (1) investigate whether CHH individuals harbor mutations in members of the so-called "FGF8 synexpression" group and (2) validate the ability of a bioinformatics algorithm on the basis of protein-protein interactome data (interactome-based affiliation scoring [IBAS]) to identify high-quality candidate genes. On the basis of sequence homology, expression, and structural and functional data, seven genes were selected and sequenced in 386 unrelated CHH individuals and 155 controls. Except for FGF18 and SPRY2, all other genes were found to be mutated in CHH individuals: FGF17 (n = 3 individuals), IL17RD (n = 8), DUSP6 (n = 5), SPRY4 (n = 14), and FLRT3 (n = 3). Independently, IBAS predicted FGF17 and IL17RD as the two top candidates in the entire proteome on the basis of a statistical test of their protein-protein interaction patterns to proteins known to be altered in CHH. Most of the FGF17 and IL17RD mutations altered protein function in vitro. IL17RD mutations were found only in KS individuals and were strongly linked to hearing loss (6/8 individuals). Mutations in genes encoding components of the FGF pathway are associated with complex modes of CHH inheritance and act primarily as contributors to an oligogenic genetic architecture underlying CHH.
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Affiliation(s)
- Hichem Miraoui
- Faculty of Biology and Medicine, University of Lausanne in collaboration with Service of Endocrinology, Diabetology, and Metabolism, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon 7, Lausanne CH-1005, Switzerland
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Comparative functional analysis of two fibroblast growth factor receptor 1 (FGFR1) mutations affecting the same residue (R254W and R254Q) in isolated hypogonadotropic hypogonadism (IHH). Gene 2013; 516:146-51. [DOI: 10.1016/j.gene.2012.12.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 12/02/2012] [Indexed: 11/18/2022]
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Suppression of β1-integrin in gonadotropin-releasing hormone cells disrupts migration and axonal extension resulting in severe reproductive alterations. J Neurosci 2013; 32:16992-7002. [PMID: 23175850 DOI: 10.1523/jneurosci.3057-12.2012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Reproduction in mammals is dependent on the function of hypothalamic neurons whose axons project to the hypothalamic median eminence (ME) where they release gonadotropin-releasing hormone (GnRH) into a specialized capillary network for delivery to the anterior pituitary. These neurons originate prenatally in the nasal placode and migrate into the forebrain along the olfactory-vomeronasal nerves. The complex developmental events leading to the correct establishment of the GnRH system are tightly regulated by the specific spatiotemporal expression patterns of guidance cues and extracellular matrix molecules, the functions of which, in part, are mediated by their binding to β1-subunit-containing integrins. To determine the biological role of these cell-surface proteins in reproduction, Cre/LoxP technology was used to generate GnRH neuron-specific β1-integrin conditional KO (GnRH-Itgb1(-/-)) mice. Loss of β1-integrin signaling impaired migration of GnRH neurons, their axonal extension to the ME, timing of pubertal onset, and fertility in these mice. These results identify β1-integrin as a gene involved in normal development of the GnRH system and demonstrate a fundamental role for this protein in acquisition of normal reproductive competence in female mice.
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Hu Y, Poopalasundaram S, Graham A, Bouloux PM. GnRH neuronal migration and olfactory bulb neurite outgrowth are dependent on FGF receptor 1 signaling, specifically via the PI3K p110α isoform in chick embryo. Endocrinology 2013; 154:388-99. [PMID: 23150492 DOI: 10.1210/en.2012-1555] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fibroblast growth factor (FGF) signaling is essential for both olfactory bulb (OB) morphogenesis and the specification, migration, and maturation of the GnRH-secreting neurons. Disruption of FGF signaling contributes to Kallmann syndrome characterized by both anosmia and sexual immaturity. However, several unanswered questions remain as to which specific FGF receptor (FGFR)-1 signaling pathways are necessary for OB and GnRH neuronal development. Here, using pharmacological phosphatidylinositol 3-kinase (PI3K) isoform-specific inhibitors, we demonstrate a central role for the PI3K p110α isoform as a downstream effector of FGFR1 signaling for both GnRH neuronal migration and OB development. We show that signaling via the PI3K p110α isoform is required for GnRH neuronal migration in explant cultures of embryonic day (E) 4 chick olfactory placodes. We also show that in ovo administration of LY294002, a global PI3K inhibitor as well as an inhibitor to the PI3K p110α isoform into the olfactory placode of E3 chick embryo impairs GnRH neuronal migration toward the forebrain. In contrast, in ovo PI3K inhibitor treatment produced no obvious defects on primary olfactory sensory neuron axonal targeting and bundle formation. We also demonstrate that anosmin-1 and FGF2 induced neuronal migration of immortalized human embryonic GnRH neuroblast cells (FNC-B4-hTERT) is mediated by modulating FGFR1 signaling via the PI3K p110α isoform, specifically through phosphorylation of the PI3K downstream effectors, Akt and glycogen synthase kinase-3β. Finally, we show that neurite outgrowth and elongation of OB neurons in E10 chick OB explants are also dependent on the PI3K p110α isoform downstream of FGFR1. This study provides mechanistic insight into the etiology of Kallmann syndrome.
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Affiliation(s)
- Youli Hu
- Centre for Neuroendocrinology, University College London Medical School, Royal Free Campus, London NW3 2PF, United Kingdom.
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Rochester JR, Chung WCJ, Hayes TB, Tsai PS. Opposite-sex housing reactivates the declining GnRH system in aged transgenic male mice with FGF signaling deficiency. Am J Physiol Endocrinol Metab 2012; 303:E1428-39. [PMID: 23047985 PMCID: PMC3532464 DOI: 10.1152/ajpendo.00289.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The continued presence of gonadotropin-releasing hormone (GnRH) neurons is required for a healthy reproductive lifespan, but factors that maintain postnatal GnRH neurons have not been identified. To begin to understand these factors, we investigated whether 1) fibroblast growth factor (FGF) signaling and 2) interactions with the opposite sex are involved in the maintenance of the postnatal GnRH system. A transgenic mouse model (dnFGFR mouse) with the targeted expression of a dominant-negative FGF receptor (dnFGFR) in GnRH neurons was used to examine the consequence of FGF signaling deficiency on postnatal GnRH neurons. Male dnFGFR mice suffered a significant loss of postnatal GnRH neurons within the first 100 days of life. Interestingly, this loss was reversed after cohabitation with female, but not male, mice for 300-550 days. Along with a rescue in GnRH neuron numbers, opposite-sex housing in dnFGFR males also increased hypothalamic GnRH peptide levels, promoted a more mature GnRH neuronal morphology, facilitated litter production, and enhanced testicular morphology. Last, mice hypomorphic for FGFR3 exhibited a similar pattern of postnatal GnRH neuronal loss as dnFGFR males, suggesting FGF signaling acts, in part, through FGFR3 to enhance the maintenance of the postnatal GnRH system. In summary, we have shown that FGF signaling is required for the continued presence of postnatal GnRH neurons. However, this requirement is not absolute, since sexual interactions can compensate for defects in FGFR signaling, thereby rescuing the declining GnRH system. This suggests the postnatal GnRH system is highly plastic and capable of responding to environmental stimuli throughout adult life.
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Affiliation(s)
- Johanna R Rochester
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80309, USA.
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Evidence that FGFR1 loss-of-function mutations may cause variable skeletal malformations in patients with Kallmann syndrome. Adv Med Sci 2012; 57:314-21. [PMID: 23154428 DOI: 10.2478/v10039-012-0036-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Loss-of-function mutations in FGFR1 have been identified in approximately 10% of the Kallmann syndrome (KS) patients. Previous reports have focused mainly on olfactory, reproductive, and some other features such as cleft lip/palate and dental agenesis. Given the ubiquitous expression of FGFR1 during development, other abnormal phenotypes might, however, have been overlooked in these patients. Here, we demonstrate skeletal phenotypic characterization of patients presented with KS and FGFR1 mutations. MATERIAL AND METHODS Using the Sanger DNA sequencing technique a cohort of 29 KS patients was screened. RESULTS Here, we report on 5 KS patients who carry FGFR1 mutations (Gly270Asp, Gly97Ser, Met161Thr, Ser685Phe and Ala167Ser/Ala167Ser). Three patients presented with skeletal abnormalities, i.e. spine (hemivertebra and butterfly vertebra) and limb (oligodactyly of the feet, fusion of the 4th and 5th metacarpal bones) malformations in two patients and one patient, respectively. The hand phenotype found in the patient cannot be thought of as a counter-type of the hand phenotype resulting from FGFR1 gain-of-function mutations. The skeletal anomalies identified in the 3 KS patients are close to those observed in Fgfr1 conditional knockout mice. CONCLUSIONS This study demonstrates that FGFR1 loss-of-function mutations can be associated with skeletal abnormalities also in humans. Further investigations in KS patients who carry FGFR1 mutations are needed to evaluate the prevalence of skeletal defects in this genetic form of KS. Conversely, the presence of bone malformations in a KS patient should direct the geneticist towards a search for mutations in FGFR1.
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Low VF, Fiorini Z, Fisher L, Jasoni CL. Netrin-1 stimulates developing GnRH neurons to extend neurites to the median eminence in a calcium- dependent manner. PLoS One 2012; 7:e46999. [PMID: 23056554 PMCID: PMC3467286 DOI: 10.1371/journal.pone.0046999] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 09/11/2012] [Indexed: 11/23/2022] Open
Abstract
Hypothalamic gonadotropin-releasing hormone (GnRH) neurons are required for fertility in all mammalian species studied to date. In rodents, GnRH neuron cell bodies reside in the rostral hypothalamus, and most extend a single long neuronal process in the caudal direction to terminate at the median eminence (ME), the site of hormone secretion. The molecular cues that GnRH neurites use to grow and navigate to the ME during development, however, remain poorly described. Reverse transcription-PCR (RT-PCR) identified mRNAs encoding Netrin-1, and its receptor, DCC, in the fetal preoptic area (POA) and mediobasal hypothalamus (MBH), respectively, from gestational day 12.5 (GD12.5), a time when the first GnRH neurites extend toward the MBH. Moreover, a subpopulation of GnRH neurons from GD14.5 through GD18.5 express the Netrin-1 receptor, DCC, suggesting a role for Netrin-1/DCC signaling in GnRH neurite growth and/or guidance. In support of this notion, when GD15.5 POA explants, containing GnRH neurons actively extending neurites, were grown in three-dimensional collagen gels and challenged with exogenous Netrin-1 (100 ng/ml or 400 ng/ml) GnRH neurite growth was stimulated. In addition, Netrin-1 provided from a fixed source was able to stimulate outgrowth, although it did not appear to chemoattract GnRH neurites. Finally, the effects of Netrin-1 on the outgrowth of GnRH neurites could be inhibited by blocking either L-type voltage-gated calcium channels (VGCCs) with nifedipine (10 µM), or ryanodine receptors with ryanodine (10 µM). This is consistent with the role of Ca2+ from extra- and intracellular sources in Netrin-1/DCC-dependent growth cone motility in other neurons. These results indicate that Netrin-1 directly stimulates the growth of a subpopulation of GnRH neurites that express DCC, provide further understanding of the mechanisms by which GnRH nerve terminals arrive at their site of hormone secretion, and identify an additional neuronal population whose neurites utilize Netrin-1/DCC signaling for their development.
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Affiliation(s)
- Victoria F. Low
- Centre for Neuroendocrinology, Department of Anatomy, University of Otago, School of Medical Sciences, Dunedin, New Zealand
| | - Zeno Fiorini
- Centre for Neuroendocrinology, Department of Anatomy, University of Otago, School of Medical Sciences, Dunedin, New Zealand
| | - Lorryn Fisher
- Centre for Neuroendocrinology, Department of Anatomy, University of Otago, School of Medical Sciences, Dunedin, New Zealand
| | - Christine L. Jasoni
- Centre for Neuroendocrinology, Department of Anatomy, University of Otago, School of Medical Sciences, Dunedin, New Zealand
- * E-mail:
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Brooks LR, Le CDV, Chung WC, Tsai PS. Maternal behavior in transgenic mice with reduced fibroblast growth factor receptor function in gonadotropin-releasing hormone neurons. Behav Brain Funct 2012; 8:47. [PMID: 22950531 PMCID: PMC3503805 DOI: 10.1186/1744-9081-8-47] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 09/02/2012] [Indexed: 11/17/2022] Open
Abstract
Background Fibroblast growth factors (FGFs) and their receptors (FGFRs) are necessary for the proper development of gonadotropin-releasing hormone (GnRH) neurons, which are key activators of the hypothalamo-pituitary-gonadal axis. Transgenic mice that have the targeted expression of a dominant negative FGFR (dnFGFR) in GnRH neurons (dnFGFR mice) have a 30% decrease of GnRH neurons. Additionally, only 30–40% of the pups born to the transgenic dams survive to weaning age. These data raised the possibility that FGFR defects in GnRH neurons could adversely affect maternal behavior via novel mechanisms. Methods We first determined if defective maternal behavior in dnFGFR mothers may contribute to poor pup survival by measuring pup retrieval and a battery of maternal behaviors in primiparous control (n = 10–12) and dnFGFR (n = 13–14) mothers. Other endocrine correlates of maternal behaviors, including plasma estradiol levels and hypothalamic pro-oxyphysin and GnRH transcript levels were also determined using enzyme-linked immunoassay and quantitative reverse transcription polymerase chain reaction, respectively. Results Maternal behaviors (% time crouching with pups, time off pups but not feeding, time feeding, and total number of nesting bouts) were not significantly different in dnFGFR mice. However, dnFGFR dams were more likely to leave their pups scattered and took significantly longer to retrieve each pup compared to control dams. Further, dnFGFR mothers had significantly lower GnRH transcripts and circulating E2, but normal pro-oxyphysin transcript levels. Conclusions Overall, this study suggests a complex scenario in which a GnRH system compromised by reduced FGF signaling leads to not only suboptimal reproductive physiology, but also suboptimal maternal behavior.
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Affiliation(s)
- Leah R Brooks
- University of Colorado, Integrative Physiology and Center for Neuroscience, UCB 354, Clare Small Rm, 114, Boulder, CO 80309-0354, USA.
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Yang JJ, Caligioni CS, Chan YM, Seminara SB. Uncovering novel reproductive defects in neurokinin B receptor null mice: closing the gap between mice and men. Endocrinology 2012; 153:1498-508. [PMID: 22253416 PMCID: PMC3281542 DOI: 10.1210/en.2011-1949] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Patients bearing mutations in TAC3 and TACR3 (which encode neurokinin B and its receptor, respectively) have sexual infantilism and infertility due to GnRH deficiency. In contrast, Tacr3(-/-) mice have previously been reported to be fertile. Because of this apparent phenotypic discordance between mice and men bearing disabling mutations in Tacr3/TACR3, Tacr3 null mice were phenotyped with close attention to pubertal development, estrous cyclicity, and fertility. Tacr3(-/-) mice demonstrated normal timing of preputial separation and day of first estrus, markers of sexual maturation. However, at postnatal d 60, Tacr3(-/-) males had significantly smaller testes and lower FSH levels than their wild-type littermates. Tacr3(-/-) females had lower uterine weights and abnormal estrous cyclicity. Approximately half of Tacr3(-/-) females had no detectable corpora lutea on ovarian histology at postnatal d 60. Despite this apparent ovulatory defect, all Tacr3(-/-) females achieved fertility when mated. However, Tacr3(-/-) females were subfertile, having both reduced numbers of litters and pups per litter. The subfertility of these animals was not due to a primary ovarian defect, because they demonstrated a robust response to exogenous gonadotropins. Thus, although capable of fertility, Tacr3-deficient mice have central reproductive defects. The remarkable ability of acyclic female Tacr3 null mice to achieve fertility is reminiscent of the reversal of hypogonadotropic hypogonadism seen in a high proportion of human patients bearing mutations in TACR3. Tacr3 mice are a useful model to examine the mechanisms by which neurokinin B signaling modulates GnRH release.
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Affiliation(s)
- Jasmine J Yang
- Harvard Reproductive Sciences Center, Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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Sabado V, Barraud P, Baker CVH, Streit A. Specification of GnRH-1 neurons by antagonistic FGF and retinoic acid signaling. Dev Biol 2012; 362:254-62. [PMID: 22200593 PMCID: PMC4561506 DOI: 10.1016/j.ydbio.2011.12.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 11/25/2022]
Abstract
A small population of neuroendocrine cells in the rostral hypothalamus and basal forebrain is the key regulator of vertebrate reproduction. They secrete gonadotropin-releasing hormone (GnRH-1), communicate with many areas of the brain and integrate multiple inputs to control gonad maturation, puberty and sexual behavior. In humans, disruption of the GnRH-1 system leads to hypogonadotropic gonadism and Kallmann syndrome. Unlike other neurons in the central nervous system, GnRH-1 neurons arise in the periphery, however their embryonic origin is controversial, and the molecular mechanisms that control their initial specification are not clear. Here, we provide evidence that in chick GnRH-1 neurons originate in the olfactory placode, where they are specified shortly after olfactory sensory neurons. FGF signaling is required and sufficient to induce GnRH-1 neurons, while retinoic acid represses their formation. Both pathways regulate and antagonize each other and our results suggest that the timing of signaling is critical for normal GnRH-1 neuron formation. While Kallmann's syndrome has generally been attributed to a failure of GnRH-1 neuron migration due to impaired FGF signaling, our findings suggest that in at least some Kallmann patients these neurons may never be specified. In addition, this study highlights the intimate embryonic relationship between GnRH-1 neurons and their targets and modulators in the adult.
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Affiliation(s)
- Virginie Sabado
- Department of Craniofacial Development, King’s College London, Guy’s Campus, London, SE1 9RT, UK
| | - Perrine Barraud
- Department of Physiology, Development & Neuroscience, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Clare V. H. Baker
- Department of Physiology, Development & Neuroscience, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Andrea Streit
- Department of Craniofacial Development, King’s College London, Guy’s Campus, London, SE1 9RT, UK
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Bonomi M, Libri DV, Guizzardi F, Guarducci E, Maiolo E, Pignatti E, Asci R, Persani L. New understandings of the genetic basis of isolated idiopathic central hypogonadism. Asian J Androl 2011; 14:49-56. [PMID: 22138902 DOI: 10.1038/aja.2011.68] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Idiopathic hypogonadotropic hypogonadism is a rare disease that is characterized by delayed/absent puberty and/or infertility due to an insufficient stimulation of an otherwise normal pituitary-gonadal axis by gonadotrophin-releasing hormone (GnRH) action. Because reduced or normal luteinizing hormone (LH)/follicle-stimulating hormone (FSH) levels may be observed in the affected patients, the term idiopathic central hypogonadism (ICH) appears to be more appropriate. This disease should be distinguished from central hypogonadism that is combined with other pituitary deficiencies. Isolated ICH has a complex pathogenesis and is fivefold more prevalent in males. ICH frequently appears in a sporadic form, but several familial cases have also been reported. This finding, in conjunction with the description of numerous pathogenetic gene variants and the generation of several knockout models, supports the existence of a strong genetic component. ICH may be associated with several morphogenetic abnormalities, which include osmic defects that, with ICH, constitute the cardinal manifestations of Kallmann syndrome (KS). KS accounts for approximately 40% of the total ICH cases and has been generally considered to be a distinct subgroup. However, the description of several pedigrees, which include relatives who are affected either with isolated osmic defects, KS, or normo-osmic ICH (nICH), justifies the emerging idea that ICH is a complex genetic disease that is characterized by variable expressivity and penetrance. In this context, either multiple gene variants or environmental factors and epigenetic modifications may contribute to the variable disease manifestations. We review the genetic mechanisms that are presently known to be involved in ICH pathogenesis and provide a clinical overview of the 227 cases that have been collected by the collaborating centres of the Italian ICH Network.
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Affiliation(s)
- Marco Bonomi
- Division of Endocrinology and Metabolism, Istituto Auxologico Italiano IRCCS, Milan, Italy
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Abstract
The gene for X-linked Kallmann's syndrome (KAL-1, encoding anosmin-1) was cloned in 1991. Over a decade elapsed before autosomal forms of KS and most of other genetic forms of isolated hypogonadotrophic hypogonadism (IHH) became characterized, and the genetic diversity of these disorders fully appreciated. Although KAL-1 mutations appear to cause a more severe reproductive phenotype than other IHH genes, the biology of this multidomain extracellular matrix protein has only been partially characterized. Initial studies suggested a central role of anosmin-1, in GnRH neuron ontogeny - specifically in GnRH neuronal migration from the cribriform plate area into the brain - as well as in olfactory bulb development. Anosmin-1 is expressed extracellularly, with high affinity binding to cell membrane heparan sulphate proteoglycans. It is expressed in the outer layers of the developing olfactory bulb, the neuroretina, the cerebellum, spinal cord and developing kidney. Recent observations have demonstrated an anosmin-1 heparan sulphate dependent functional interaction with the product of the autosomal dominant KAL-2 (FGFR1: anosmin-2) gene, thereby modulating FGFR1 signalling. Although these genes are frequently co-expressed in developing tissues, this may not represent the sole mode of action of anosmin-1, and FGFR1 independent actions of the protein have also been identified. Structural and in vitro functional studies have shown that anosmin-1 may have complex biological actions. Anosmin-1 interactions with FGFR1 have however been best characterized and represent the dominant focus of this chapter.
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Affiliation(s)
- Youli Hu
- Centre for Neuroendocrinology, UCL Medical School, Royal Free Campus, London NW3 2QG, UK.
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Miraoui H, Dwyer A, Pitteloud N. Role of fibroblast growth factor (FGF) signaling in the neuroendocrine control of human reproduction. Mol Cell Endocrinol 2011; 346:37-43. [PMID: 21664428 PMCID: PMC3185130 DOI: 10.1016/j.mce.2011.05.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/27/2011] [Indexed: 12/20/2022]
Abstract
Fibroblast growth factor (FGF) signaling is critical for a broad range of developmental processes. In 2003, Fibroblast growth factor receptor 1 (FGFR1) was discovered as a novel locus causing both forms of isolate GnRH Deficiency, Kallmann syndrome [KS with anosmia] and normosmic idiopathic hypogonadotropic hypogonadism [nIHH] eventually accounting for approximately 10% of gonadotropin-releasing hormone (GnRH) deficiency cases. Such cases are characterized by a broad spectrum of reproductive phenotypes from severe congenital forms of GnRH deficiency to reversal of HH. Additionally, the variable expressivity of both reproductive and non-reproductive phenotypes among patients and family members harboring the identical FGFR1 mutations has pointed to a more complex, oligogenic model for GnRH deficiency. Further, reversal of HH in patients carrying FGFR1 mutations suggests potential gene-environment interactions in human GnRH deficiency disorders.
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Affiliation(s)
- Hichem Miraoui
- Centre Hospitalier Universitaire Vaudois, Endocrine, Diabetes, & Metabolism Service, BH 19-701, Rue du Bugnon 46, 1011 Lausanne, Switzerland
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Regulation of temporal and spatial organization of newborn GnRH neurons by IGF signaling in zebrafish. J Neurosci 2011; 31:11814-24. [PMID: 21849542 DOI: 10.1523/jneurosci.6804-10.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
When and how newborn neurons are organized to form a functional network in the developing brain remains poorly understood. An attractive model is the gonadotropin-releasing hormone (GnRH) neuron system, master regulator of the reproductive axis. Here we show that blockage of IGF signaling, a central growth-promoting signaling pathway, by the induced expression of a dominant-negative form of IGF1 receptor (IGF1R) or specific IGF1R inhibitors delayed the emergence of GnRH2 neurons in the midbrain and GnRH3 neurons in the olfactory bulb region. Blockage of IGF signaling also resulted in an abnormal appearance of GnRH3 neurons outside of the olfactory bulb region, although it did not change the locations of other olfactory neurons, GnRH2 neurons, or brain patterning. This IGF action is developmental stage-dependent because the blockade of IGF signaling in advanced embryos had no such effect. An application of phosphatidylinositol 3-kinase (PI3K) inhibitors phenocopied the IGF signaling deficient embryos, whereas the MAPK inhibitors had no effect, suggesting that this IGF action is mediated through the PI3K pathway. Real-time in vivo imaging studies revealed that the ectopic GnRH3 neurons emerged at the same time as the normal GnRH3 neurons in IGF-deficient embryos. Further experiments suggest that IGF signaling affects the spatial distribution of newborn GnRH3 neurons by influencing neural crest cell migration and/or differentiation. These results suggest that the IGF-IGF1R-PI3K pathway regulates the precise temporal and spatial organization of GnRH neurons in zebrafish and provides new insights into the regulation of GnRH neuron development.
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Neural crest and ectodermal cells intermix in the nasal placode to give rise to GnRH-1 neurons, sensory neurons, and olfactory ensheathing cells. J Neurosci 2011; 31:6915-27. [PMID: 21543621 DOI: 10.1523/jneurosci.6087-10.2011] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The origin of GnRH-1 cells and olfactory ensheathing cells has been controversial. Genetic Cre-lox lineage tracing of the neural crest (NC) versus ectodermal contribution to the developing nasal placode was performed using two complementary mouse models, the NC-specific Wnt1Cre mouse line and an ectodermal-specific Crect mouse line. Using these lines we prove that the NC give rise to the olfactory ensheathing cells and subpopulations of GnRH-1 neurons, olfactory and vomeronasal cells. These data demonstrate that Schwann cells and olfactory ensheathing cells share a common developmental origin. Furthermore, the results indicate that certain conditions that impact olfaction and sexual development, such as Kallmann syndrome, may be in part neurocristopathies.
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Layman WS, Hurd EA, Martin DM. Reproductive dysfunction and decreased GnRH neurogenesis in a mouse model of CHARGE syndrome. Hum Mol Genet 2011; 20:3138-50. [PMID: 21596839 DOI: 10.1093/hmg/ddr216] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
CHARGE is a multiple congenital anomaly disorder and a common cause of pubertal defects, olfactory dysfunction, growth delays, deaf-blindness, balance disorders and congenital heart malformations. Mutations in CHD7, the gene encoding chromodomain helicase DNA binding protein 7, are present in 60-80% of individuals with the CHARGE syndrome. Mutations in CHD7 have also been reported in the Kallmann syndrome (olfactory dysfunction, delayed puberty and hypogonadotropic hypogonadism). CHD7 is a positive regulator of neural stem cell proliferation and olfactory sensory neuron formation in the olfactory epithelium, suggesting that the loss of CHD7 might also disrupt development of other neural populations. Here we report that female Chd7(Gt/+) mice have delays in vaginal opening and estrus onset, and erratic estrus cycles. Chd7(Gt/+) mice also have decreased circulating levels of luteinizing hormone and follicle-stimulating hormone but apparently normal responsiveness to gonadotropin-releasing hormone (GnRH) agonist and antagonist treatment. GnRH neurons in the adult Chd7(Gt/+) hypothalamus and embryonic nasal region are diminished, and there is decreased cellular proliferation in the embryonic olfactory placode. Expression levels of GnRH1 and Otx2 in the hypothalamus and GnRHR in the pituitary are significantly reduced in adult Chd7(Gt/+) mice. Additionally, Chd7 mutant embryos have CHD7 dosage-dependent reductions in expression levels of Fgfr1, Bmp4 and Otx2 in the olfactory placode. Together, these data suggest that CHD7 has critical roles in the development and maintenance of GnRH neurons for regulating puberty and reproduction.
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Affiliation(s)
- Wanda S Layman
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109-5652, USA
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Ojeda SR, Lomniczi A, Sandau U. Contribution of glial-neuronal interactions to the neuroendocrine control of female puberty. Eur J Neurosci 2011; 32:2003-10. [PMID: 21143655 DOI: 10.1111/j.1460-9568.2010.07515.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mammalian puberty is initiated by an increased pulsatile release of the neuropeptide gonadotropin-releasing hormone (GnRH) from hypothalamic neuroendocrine neurons. Although this increase is primarily set in motion by neuronal networks synaptically connected to GnRH neurons, glial cells contribute to the process via at least two mechanisms. One involves production of growth factors acting via receptors endowed with either serine-threonine kinase or tyrosine kinase activity. The other involves plastic rearrangements of glia-GnRH neuron adhesiveness. Growth factors of the epidermal growth factor family acting via erbB receptors play a major role in glia-to-GnRH neuron communication. In turn, neurons facilitate astrocytic erbB signaling via glutamate-dependent cleavage of erbB ligand precursors. The genetic disruption of erbB receptors delays female sexual development due to impaired erbB ligand-induced glial prostaglandin E(2) release. The adhesiveness of glial cells to GnRH neurons involves at least two different cell-cell communication systems endowed with both adhesive and intracellular signaling capabilities. One is provided by synaptic cell adhesion molecule (SynCAM1), which establishes astrocyte-GnRH neuron adhesiveness via homophilic interactions and the other involves the heterophilic interaction of neuronal contactin with glial receptor-like protein tyrosine phosphatase-β. These findings indicate that the interaction of glial cells with GnRH neurons involves not only secreted bioactive molecules, but also cell-surface adhesive proteins able to set in motion intracellular signaling cascades.
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Affiliation(s)
- Sergio R Ojeda
- Division of Neuroscience, Oregon National Primate Research Center/Oregon Health Sciences University, 505 N.W., 185th Avenue, Beaverton, OR 97006, USA.
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Tsai PS, Brooks LR, Rochester JR, Kavanaugh SI, Chung WCJ. Fibroblast growth factor signaling in the developing neuroendocrine hypothalamus. Front Neuroendocrinol 2011; 32:95-107. [PMID: 21129392 PMCID: PMC3050526 DOI: 10.1016/j.yfrne.2010.11.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 11/03/2010] [Accepted: 11/24/2010] [Indexed: 11/29/2022]
Abstract
Fibroblast growth factor (FGF) signaling is pivotal to the formation of numerous central regions. Increasing evidence suggests FGF signaling also directs the development of the neuroendocrine hypothalamus, a collection of neuroendocrine neurons originating primarily within the nose and the ventricular zone of the diencephalon. This review outlines evidence for a role of FGF signaling in the prenatal and postnatal development of several hypothalamic neuroendocrine systems. The emphasis is placed on the nasally derived gonadotropin-releasing hormone neurons, which depend on neurotrophic cues from FGF signaling throughout the neurons' lifetime. Although less is known about neuroendocrine neurons derived from the diencephalon, recent studies suggest they also exhibit variable levels of dependence on FGF signaling. Overall, FGF signaling provides a broad spectrum of cues that ranges from genesis, cell survival/death, migration, morphological changes, to hormone synthesis in the neuroendocrine hypothalamus. Abnormal FGF signaling will deleteriously impact multiple hypothalamic neuroendocrine systems, resulting in the disruption of diverse physiological functions.
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Affiliation(s)
- Pei-San Tsai
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado, Boulder, CO 80309-0354, USA.
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Wierman ME, Kiseljak-Vassiliades K, Tobet S. Gonadotropin-releasing hormone (GnRH) neuron migration: initiation, maintenance and cessation as critical steps to ensure normal reproductive function. Front Neuroendocrinol 2011; 32:43-52. [PMID: 20650288 PMCID: PMC3008544 DOI: 10.1016/j.yfrne.2010.07.005] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 07/08/2010] [Accepted: 07/14/2010] [Indexed: 12/23/2022]
Abstract
GnRH neurons follow a carefully orchestrated journey from their birth in the olfactory placode area. Initially, they migrate along with the vomeronasal nerve into the brain at the cribriform plate, then progress caudally to sites within the hypothalamus where they halt and send projections to the median eminence to activate pituitary gonadotropes. Many factors controlling this precise journey have been elucidated by the silencing or over-expression of candidate genes in mouse models. Importantly, a number of these factors may not only play a role in normal physiology of the hypothalamic-pituitary-gonadal axis but also be mis-expressed to cause human disorders of GnRH deficiency, presenting as a failure to undergo normal pubertal development. This review outlines the current cadre of candidates thought to modulate GnRH neuronal migration. The further elucidation and characterization of these factors that impact GnRH neuron development may shed new light on human reproductive disorders and provide potential targets to develop new pro-fertility or contraceptive agents.
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Affiliation(s)
- Margaret E Wierman
- Department of Medicine, University of Colorado-Denver, Aurora, CO 80045, USA
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Fiorini Z, Jasoni CL. A novel developmental role for kisspeptin in the growth of gonadotrophin-releasing hormone neurites to the median eminence in the mouse. J Neuroendocrinol 2010; 22:1113-25. [PMID: 20722977 DOI: 10.1111/j.1365-2826.2010.02059.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The puberty- and fertility-regulating neuropeptide kisspeptin (KISS1) exerts dramatic effects on the physiology of adult gonadotrophin-releasing hormone (GnRH) neurones as a master regulator of mammalian reproduction. Given the action of KISS1 directly on adult GnRH neurones, and that KISS1 activates a signal transduction cascade involved in neurite growth in other neurones, we investigated whether KISS1 may play a role in the normal growth of GnRH neurites to the median eminence. A reverse transcription-polymerase chain reaction demonstrated the expression of Kiss1 mRNA in the embryonic mediobasal hypothalamus, the target region for GnRH neurite termination, as early as embryonic day 13.5 (E13.5), a time when the first GnRH neurites are arriving. Complementary expression of the mRNA encoding the KISS1 receptor, Kiss1r, in the preoptic area (POA) at E13.5 was also observed, suggesting that POA-resident GnRH neurones can respond to KISS1 from an early age. To examine the effects of KISS1 on GnRH neurite growth in isolation, E15.5 POA explants, containing GnRH neurones actively extending neurites, were grown in three-dimensional collagen gels. In the presence of KISS1 (1 μm), both the number and length of GnRH neurites were increased significantly compared to controls without KISS1. The effects of KISS1 on GnRH neurite growth could be inhibited by pretreatment with the phospholipase C inhibitor U73122 (50 μm), indicating that embryonic and adult GnRH neurones respond to KISS1 with the same intracellular signalling pathway. KISS1 provided in a concentration gradient from a fixed source had no effect on GnRH neurite growth, indicating that KISS1 does not function as a long-range chemoattractant. Taken together, these results identify KISS1 as a stimulator of GnRH neurite growth, and suggest that it influences GnRH neurites at close-range to innervate the median eminence. These data add a novel developmental role to the repertoire of the functions of KISS1 in mammalian reproduction.
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Affiliation(s)
- Z Fiorini
- Centre for Neuroendocrinology, Department of Anatomy & Structural Biology, University of Otago School of Medical Sciences, Dunedin, New Zealand
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46
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Abstract
This article reviews symptoms and signs of aberrant axon connectivity in humans, and summarizes major human genetic disorders that result, or have been proposed to result, from defective axon guidance. These include corpus callosum agenesis, L1 syndrome, Joubert syndrome and related disorders, horizontal gaze palsy with progressive scoliosis, Kallmann syndrome, albinism, congenital fibrosis of the extraocular muscles type 1, Duane retraction syndrome, and pontine tegmental cap dysplasia. Genes mutated in these disorders can encode axon growth cone ligands and receptors, downstream signaling molecules, and axon transport motors, as well as proteins without currently recognized roles in axon guidance. Advances in neuroimaging and genetic techniques have the potential to rapidly expand this field, and it is feasible that axon guidance disorders will soon be recognized as a new and significant category of human neurodevelopmental disorders.
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Chung WCJ, Matthews TA, Tata BK, Tsai PS. Compound deficiencies in multiple fibroblast growth factor signalling components differentially impact the murine gonadotrophin-releasing hormone system. J Neuroendocrinol 2010; 22:944-50. [PMID: 20553372 PMCID: PMC3102046 DOI: 10.1111/j.1365-2826.2010.02024.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gonadotrophin-releasing hormone (GnRH) neurones control the onset and maintenance of fertility. Aberrant development of the GnRH system underlies infertility in Kallmann syndrome [KS; idiopathic hypogonadotropic hypogonadism (IHH) and anosmia]. Some KS patients harbour mutations in the fibroblast growth factor receptor 1 (Fgfr1) and Fgf8 genes. The biological significance of these two genes in GnRH neuronal development was corroborated by the observation that GnRH neurones were severely reduced in newborn transgenic mice deficient in either gene. In the present study, we hypothesised that the compound deficiency of Fgf8 and its cognate receptors, Fgfr1 and Fgfr3, may lead to more deleterious effects on the GnRH system, thereby resulting in a more severe reproductive phenotype in patients harbouring these mutations. This hypothesis was tested by counting the number of GnRH neurones in adult transgenic mice with digenic heterozygous mutations in Fgfr1/Fgf8, Fgfr3/Fgf8 or Fgfr1/Fgfr3. Monogenic heterozygous mutations in Fgfr1, Fgf8 or Fgfr3 caused a 30-50% decrease in the total number of GnRH neurones. Interestingly, mice with digenic mutations in Fgfr1/Fgf8 showed a greater decrease in GnRH neurones compared to mice with a heterozygous defect in the Fgfr1 or Fgf8 alone. This compounding effect was not detected in mice with digenic heterozygous mutations in Fgfr3/Fgf8 or Fgfr1/Fgfr3. These results support the hypothesis that IHH/KS patients with digenic mutations in Fgfr1/Fgf8 may have a further reduction in the GnRH neuronal population compared to patients harbouring monogenic haploid mutations in Fgfr1 or Fgf8. Because only Fgfr1/Fgf8 compound deficiency leads to greater GnRH system defect, this also suggests that these fibroblast growth factor signalling components interact in a highly specific fashion to support GnRH neuronal development.
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MESH Headings
- Animals
- Fibroblast Growth Factor 8/genetics
- Fibroblast Growth Factor 8/metabolism
- Gonadotropin-Releasing Hormone/metabolism
- Humans
- Hypogonadism/physiopathology
- Hypothalamus/cytology
- Hypothalamus/metabolism
- Kallmann Syndrome/physiopathology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Neurons/cytology
- Neurons/metabolism
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/metabolism
- Receptor, Fibroblast Growth Factor, Type 3/genetics
- Receptor, Fibroblast Growth Factor, Type 3/metabolism
- Signal Transduction/physiology
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Affiliation(s)
- W C J Chung
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado, Boulder, CO 80309-0354, USA.
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48
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Provenzano C, Pascucci B, Lupari E, Civitareale D. Large scale analysis of transcription factor TTF-1/NKX2.1 target genes in GnRH secreting cell line GT1-7. Mol Cell Endocrinol 2010; 323:215-23. [PMID: 20211691 DOI: 10.1016/j.mce.2010.02.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 02/26/2010] [Accepted: 02/28/2010] [Indexed: 11/24/2022]
Abstract
TTF-1/Nkx2.1 is a homeodomain-containing transcription factor required for the proper development of ventral forebrain, including some structures of the hypothalamus. TTF-1/Nkx2.1 remains expressed in the hypothalamus after birth and it plays a crucial role during sexual development. To identify putative TTF-1/Nkx2.1 target genes in GnRH neurons, we have studied the gene expression profile of the GT1-7 cells exogenously expressing TTF-1/Nkx2.1 coding gene. Our transcriptome analysis confirms that TTF-1/Nkx2.1 is involved in neuron morphogenesis and differentiation. Many of the newly identified TTF-1/Nkx2.1 target genes have a direct involvement with the central regulation of sexual maturity. In particular, we have identified Sparc as a gene directly regulated by TTF-1/Nkx2.1 at the promoter level. To further support the role of TTF-1 in GnRH neurons, we show that Sparc is involved in the regulation of the GnRH secretion in GT1-7 cells.
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Affiliation(s)
- Claudia Provenzano
- Institute of Neurobiology and Molecular Medicine, CNR, Via Fosso del Cavaliere 100, 00133 Rome, Italy
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49
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Hu Y, Bouloux PM. Novel insights in FGFR1 regulation: lessons from Kallmann syndrome. Trends Endocrinol Metab 2010; 21:385-93. [PMID: 20117945 DOI: 10.1016/j.tem.2010.01.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 12/23/2009] [Accepted: 01/07/2010] [Indexed: 01/25/2023]
Abstract
Disrupted fibroblast growth factor receptor (FGFR)1 signalling has been shown to cause Kallmann syndrome (KS), a human genetic disorder characterised by olfactory bulb dysgenesis and hypogonadotrophic hypogonadism. Loss-of-function mutations in the KS gene KAL-2/FGFR1 account for roughly 10% of KS cases, leading to the autosomal dominant form of the disease. Anosmin-1, the KAL-1 gene product underlying X-linked KS, modulates FGFR1 signalling via regulation of FGF2/FGFR1/heparin signalling complex assembly and activity. This review covers recent advances in the potential interactions of KS-associated molecules within the FGFR1 signalling complex, and demonstrates a novel mechanism of pre-signalling modulation that mechanistically links an autosomal dominant and sex-linked mode of inheritance of this disease, highlighting the central role of FGFR1 signalling in KS.
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Affiliation(s)
- Youli Hu
- Centre for Neuroendocrinology, UCL Medical School, Royal Free Campus, London NW3 2QG, UK.
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50
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Xu N, Bhagavath B, Kim HG, Halvorson L, Podolsky RS, Chorich LP, Prasad P, Xiong WC, Cameron RS, Layman LC. NELF is a nuclear protein involved in hypothalamic GnRH neuronal migration. Mol Cell Endocrinol 2010; 319:47-55. [PMID: 20025934 PMCID: PMC3437992 DOI: 10.1016/j.mce.2009.11.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 11/15/2009] [Accepted: 11/26/2009] [Indexed: 12/22/2022]
Abstract
Nasal embryonic LHRH factor (NELF) has been hypothesized to participate in the migration of GnRH and olfactory neurons into the forebrain, a prerequisite for normal hypothalamic-pituitary-gonadal function in puberty and reproduction. However, the biological functions of NELF, which has no homology to any human protein, remain largely elusive. Although mRNA expression did not differ, NELF protein expression was greater in migratory than postmigratory GnRH neurons. Pituitary Nelf mRNA expression was also observed and increased 3-fold after exogenous GnRH administration. Contrary to a previous report, NELF displayed predominant nuclear localization in GnRH neurons, confirmed by mutagenesis of a putative nuclear localization signal resulting in impaired nuclear expression. NELF knockdown impaired GnRH neuronal migration of NLT cells in vitro. These findings and the identification of two putative zinc fingers suggest that NELF could be a transcription factor. Collectively, our findings implicate NELF as a nuclear protein involved in the developmental function of the reproductive axis.
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Affiliation(s)
- Ning Xu
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Reproductive Medicine and Developmental Neurobiology Programs in the Institute of Molecular Medicine and Genetics; Neuroscience Program, The Medical College of Georgia, 1120 15th Street, Augusta, GA 30912
- Division of Endocrinology, Diabetes and Metabolism, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Becker Building, Los Angeles, CA 90048 (present address)
| | - Balasubramanian Bhagavath
- Reproductive Endocrinology and Infertility, Women and Infants Hospital, 101 Dudley Street, Providence, RI 02905
| | - Hyung-Goo Kim
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Reproductive Medicine and Developmental Neurobiology Programs in the Institute of Molecular Medicine and Genetics; Neuroscience Program, The Medical College of Georgia, 1120 15th Street, Augusta, GA 30912
| | - Lisa Halvorson
- Division of Reproductive Endocrinology and Infertility, Dept of Ob/Gyn, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Robert S. Podolsky
- Center for Biotechnology and Genomic Medicine, Department of Medicine, The Medical College of Georgia, Augusta, GA 30912
| | - Lynn P. Chorich
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Reproductive Medicine and Developmental Neurobiology Programs in the Institute of Molecular Medicine and Genetics; Neuroscience Program, The Medical College of Georgia, 1120 15th Street, Augusta, GA 30912
| | - Puttur Prasad
- Dept. Biochemistry and Molecular Biology, The Medical College of Georgia, Augusta, GA 30912
| | - Wen-Cheng Xiong
- Department of Cellular Biology and Anatomy, The Medical College of Georgia, Augusta, GA 30912
| | - Richard S. Cameron
- Developmental Neurobiology Program, The Institute of Molecular Medicine and Genetics; The Medical College of Georgia, Augusta, GA 30912
| | - Lawrence C. Layman
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology; Reproductive Medicine and Developmental Neurobiology Programs in the Institute of Molecular Medicine and Genetics; Neuroscience Program, The Medical College of Georgia, 1120 15th Street, Augusta, GA 30912
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