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Di Schiavi E, Andrenacci D. Invertebrate models of kallmann syndrome: molecular pathogenesis and new disease genes. Curr Genomics 2013; 14:2-10. [PMID: 23997646 PMCID: PMC3580776 DOI: 10.2174/138920213804999174] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 10/08/2012] [Accepted: 10/08/2012] [Indexed: 11/23/2022] Open
Abstract
Kallmann Syndrome is a heritable disorder characterized by congenital anosmia, hypogonadotropic hypogonadism and, less frequently, by other symptoms. The X-linked form of this syndrome is caused by mutations affecting the KAL1 gene that codes for the extracellular protein anosmin-1. Investigation of KAL1 function in mice has been hampered by the fact that the murine ortholog has not been identified. Thus studies performed in other animal models have contributed significantly to an understanding of the function of KAL1. In this review, the main results obtained using the two invertebrate models, the nematode worm Caenorhabditis elegans and the fruit fly Drosophila melanogaster, are illustrated and the contribution provided by them to the elucidation of the molecular pathogenesis of Kallmann Syndrome is discussed in detail. Structure-function dissection studies performed in these two animal models have shown how the different domains of anosmin-1 carry out specific functions, also suggesting a novel intramolecular regulation mechanism among the different domains of the protein. The model that emerges is one in which anosmin-1 plays different roles in different tissues, interacting with different components of the extracellular matrix. We also describe how the genetic approach in C. elegans has allowed the discovery of the genes involved in KAL1-heparan sulfate proteoglycans interactions and the identification of HS6ST1 as a new disease gene.
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Affiliation(s)
- Elia Di Schiavi
- Institute of Genetics and Biophysics, Consiglio Nazionale delle Ricerche (CNR), Naples, Italy
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Garcia-Gonzalez D, Murcia-Belmonte V, Clemente D, De Castro F. Olfactory system and demyelination. Anat Rec (Hoboken) 2013; 296:1424-34. [PMID: 23904351 DOI: 10.1002/ar.22736] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 09/18/2012] [Accepted: 11/29/2012] [Indexed: 01/04/2023]
Abstract
Within the central nervous system, the olfactory system represents one of the most exciting scenarios since it presents relevant examples of long-life sustained neurogenesis and continuous axonal outgrowth from the olfactory epithelium with the subsequent plasticity phenomena in the olfactory bulb. The olfactory nerve is composed of nonmyelinated axons with interesting ontogenetic interpretations. However, the centripetal projections from the olfactory bulb are myelinated axons which project to more caudal areas along the lateral olfactory tract. In consequence, demyelination has not been considered as a possible cause of the olfactory symptoms in those diseases in which this sense is impaired. One prototypical example of an olfactory disease is Kallmann syndrome, in which different mutations give rise to combined anosmia and hypogonadotropic hypogonadism, together with different satellite symptoms. Anosmin-1 is the extracellular matrix glycoprotein altered in the X-linked form of this disease, which participates in cell adhesion and migration, and axonal outgrowth in the olfactory system and in other regions of the central nervous system. Recently, we have described a new patho-physiological role of this protein in the absence of spontaneous remyelination in multiple sclerosis. In the present review, we hypothesize about how both main and satellite neurological symptoms of Kallmann syndrome may be explained by alterations in the myelination. We revisit the relationship between the olfactory system and myelin highlighting that minor histological changes should not be forgotten as putative causes of olfactory malfunction.
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Affiliation(s)
- D Garcia-Gonzalez
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos-SESCAM, Toledo, Spain
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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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Matsuo I, Kimura-Yoshida C. Extracellular modulation of Fibroblast Growth Factor signaling through heparan sulfate proteoglycans in mammalian development. Curr Opin Genet Dev 2013; 23:399-407. [PMID: 23465883 DOI: 10.1016/j.gde.2013.02.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 02/04/2013] [Accepted: 02/07/2013] [Indexed: 12/27/2022]
Abstract
Fibroblast Growth Factor (FGF) signaling plays crucial roles in multiple cellular processes including cell proliferation, differentiation, survival, and migration during mammalian embryogenesis. In the extracellular matrix, as well as at the cell surface, the movement of FGF ligands to target cells and the subsequent complex formations with their receptors are positively and negatively controlled extracellularly by heparan sulfate proteoglycans (HSPGs) such as syndecans, glypicans, and perlecan. Additionally, spreading of HSPGs by cleavage with sheddases such as proteinases and heparanases, and the overall length and sulfation level of specific heparan sulfate structures further generate a great diversity of FGF signaling outcomes. This review presents our current understanding of the regulatory mechanisms of FGF signaling in extracellular spaces through HSPGs in mammalian development.
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Affiliation(s)
- Isao Matsuo
- Department of Molecular Embryology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka Prefectural Hospital Organization, 840 Murodo-cho, Izumi, Osaka 594-1101, Japan.
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Geller S, Kolasa E, Tillet Y, Duittoz A, Vaudin P. Olfactory ensheathing cells form the microenvironment of migrating GnRH-1 neurons during mouse development. Glia 2013; 61:550-66. [PMID: 23404564 DOI: 10.1002/glia.22455] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 11/28/2012] [Indexed: 11/08/2022]
Abstract
During development, GnRH-1 neurons differentiate extracerebraly from the nasal placode and migrate from the vomeronasal organ to the forebrain along vomeronasal and terminal nerves. Numerous studies have described the influence of different molecules on the migration of GnRH-1 neurons, however, the role of microenvironment cells remains poorly understood. This study used GFAP-GFP transgenic mice to detect glial cells at early developmental stages. Using nasal explant cultures, the comigration of glial cells with GnRH-1 neurons was clearly demonstrated. This in vitro approach showed that glial cells began migrating from the explants before GnRH-1 neurons. They remained ahead of the GnRH-1 migratory front and stopped migrating after the GnRH-1 neurons. The association of these glial cells with the axons combined with gene expression analysis of GFAP-GFP sorted cells enabled them to be identified as olfactory ensheathing cells (OEC). Immunohistochemical analysis revealed the presence of multiple glial cell-type markers showing several OEC subpopulations surrounding GnRH-1 neurons. Moreover, these OEC expressed genes whose products are involved in the migration of GnRH-1 neurons, such as Nelf and Semaphorin 4. In situ data confirmed that the majority of the GnRH-1 neurons were associated with glial cells along the vomeronasal axons in nasal septum and terminal nerves in the nasal forebrain junction as early as E12.5. Overall, these data demonstrate an OEC microenvironment for migrating GnRH-1 neurons during mouse development. The fact that this glial cell type precedes GnRH-1 neurons and encodes for molecules involved in their nasal migration suggests that it participates in the GnRH-1 system ontogenesis.
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Affiliation(s)
- Sarah Geller
- Physiologie de la Reproduction et des Comportements, UMR 0085 INRA, 6175 CNRS, Université François Rabelais de Tours, IFCE, IFR135 Imagerie Fonctionnelle 37380, Nouzilly, France
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Stevenson EL, Corella KM, Chung WCJ. Ontogenesis of gonadotropin-releasing hormone neurons: a model for hypothalamic neuroendocrine cell development. Front Endocrinol (Lausanne) 2013; 4:89. [PMID: 23882261 PMCID: PMC3712253 DOI: 10.3389/fendo.2013.00089] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 07/02/2013] [Indexed: 02/02/2023] Open
Abstract
The vertebrate hypothalamo-pituitary-gonadal axis is the anatomical framework responsible for reproductive competence and species propagation. Essential to the coordinated actions of this three-tiered biological system is the fact that the regulatory inputs ultimately converge on the gonadotropin-releasing hormone (GnRH) neuronal system, which in rodents primarily resides in the preoptic/hypothalamic region. In this short review we will focus on: (1) the general embryonic temporal and spatial development of the rodent GnRH neuronal system, (2) the origin(s) of GnRH neurons, and (3) which transcription - and growth factors have been found to be critical for GnRH neuronal ontogenesis and cellular fate-specification. Moreover, we ask the question whether the molecular and cellular mechanisms involved in GnRH neuronal development may also play a role in the development of other hypophyseal secreting neuroendocrine cells in the hypothalamus.
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Affiliation(s)
- Erica L. Stevenson
- Department of Biological Sciences, School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Kristina M. Corella
- Department of Biological Sciences, School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Wilson C. J. Chung
- Department of Biological Sciences, School of Biomedical Sciences, Kent State University, Kent, OH, USA
- *Correspondence: Wilson C. J. Chung, Department of Biological Sciences, School of Biomedical Sciences, Kent State University, 222 Cunningham Hall, Kent, OH 44242, USA e-mail:
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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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Morelli A, Comeglio P, Sarchielli E, Cellai I, Vignozzi L, Vannelli GB, Maggi M. Negative effects of high glucose exposure in human gonadotropin-releasing hormone neurons. Int J Endocrinol 2013; 2013:684659. [PMID: 24489542 PMCID: PMC3893744 DOI: 10.1155/2013/684659] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 12/13/2013] [Accepted: 12/18/2013] [Indexed: 01/01/2023] Open
Abstract
Metabolic disorders are often associated with male hypogonadotropic hypogonadism, suggesting that hypothalamic defects involving GnRH neurons may impair the reproductive function. Among metabolic factors hyperglycemia has been implicated in the control of the reproductive axis at central level, both in humans and in animal models. To date, little is known about the direct effects of pathological high glucose concentrations on human GnRH neurons. In this study, we investigated the high glucose effects in the human GnRH-secreting FNC-B4 cells. Gene expression profiling by qRT-PCR, confirmed that FNC-B4 cells express GnRH and several genes relevant for GnRH neuron function (KISS1R, KISS1, sex steroid and leptin receptors, FGFR1, neuropilin 2, and semaphorins), along with glucose transporters (GLUT1, GLUT3, and GLUT4). High glucose exposure (22 mM; 40 mM) significantly reduced gene and protein expression of GnRH, KISS1R, KISS1, and leptin receptor, as compared to normal glucose (5 mM). Consistent with previous studies, leptin treatment significantly induced GnRH mRNA expression at 5 mM glucose, but not in the presence of high glucose concentrations. In conclusion, our findings demonstrate a deleterious direct contribution of high glucose on human GnRH neurons, thus providing new insights into pathogenic mechanisms linking metabolic disorders to reproductive dysfunctions.
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Affiliation(s)
- Annamaria Morelli
- Section of Anatomy and Histology, Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Paolo Comeglio
- Section of Sexual Medicine and Andrology, Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Erica Sarchielli
- Section of Anatomy and Histology, Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Ilaria Cellai
- Section of Sexual Medicine and Andrology, Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Linda Vignozzi
- Section of Sexual Medicine and Andrology, Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Gabriella B. Vannelli
- Section of Anatomy and Histology, Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Mario Maggi
- Section of Sexual Medicine and Andrology, Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
- Centro Interuniversitario di Ricerca sulle Basi Molecolari della Malattie della Riproduzione (CIRMAR), 20122 Milan, Italy
- *Mario Maggi:
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Esteban PF, Murcia-Belmonte V, García-González D, de Castro F. The cysteine-rich region and the whey acidic protein domain are essential for anosmin-1 biological functions. J Neurochem 2012. [PMID: 23189990 DOI: 10.1111/jnc.12104] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The protein anosmin-1, coded by the KAL1 gene responsible for the X-linked form of Kallmann syndrome (KS), exerts its biological effects mainly through the interaction with and signal modulation of fibroblast growth factor receptor 1 (FGFR1). We have previously shown the interaction of the third fibronectin-like type 3 (FnIII) domain and the N-terminal region of anosmin-1 with FGFR1. Here, we demonstrate that missense mutations reported in patients with KS, C172R and N267K did not alter or substantially reduce, respectively, the binding to FGFR1. These substitutions annulled the chemoattraction of the full-length protein over subventricular zone (SVZ) neuronal precursors (NPs), but they did not annul it in the N-terminal-truncated protein (A1Nt). We also show that although not essential for binding to FGFR1, the cysteine-rich (CR) region is necessary for anosmin-1 function and that FnIII.3 cannot substitute for FnIII.1 function. Truncated proteins recapitulating nonsense mutations found in KS patients did not show the chemotropic effect on SVZ NPs, suggesting that the presence behind FnIII.1 of any part of anosmin-1 produces an unstable protein incapable of action. We also identify the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway as necessary for the chemotropic effect exerted by FGF2 and anosmin-1 on rat SVZ NPs.
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Affiliation(s)
- Pedro F Esteban
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos, Toledo, Spain.
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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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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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Tusset C, Trarbach ÉB, Silveira LFG, Beneduzzi D, Montenegro L, Latronico AC. Aspectos clínicos e moleculares do hipogonadismo hipogonadotrófico isolado congênito. ACTA ACUST UNITED AC 2011; 55:501-11. [DOI: 10.1590/s0004-27302011000800002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 10/21/2011] [Indexed: 11/22/2022]
Abstract
O hipogonadismo hipogonadotrófico isolado (HHI) congênito caracteriza-se pela falta completa ou parcial de desenvolvimento puberal em decorrência de defeitos na migração, síntese, secreção ou ação do hormônio liberador de gonadotrofinas (GnRH). Baixas concentrações de esteroides sexuais e valores reduzidos ou inapropriadamente normais de gonadotrofinas hipofisárias (LH e FSH) definem, do ponto de vista laboratorial, essa condição clínica. A secreção dos demais hormônios hipofisários encontra-se normal, bem como a ressonância magnética de região hipotalâmica-hipofisária, demonstrando a ausência de uma causa anatômica. Alterações olfatórias, como anosmia ou hiposmia, podem estar associadas ao HHI, caracterizando a síndrome de Kallmann. Uma lista crescente de genes está envolvida na etiologia do HHI, sugerindo a heterogeneidade e a complexidade da base genética dessa condição. Distúrbios na rota de migração dos neurônios secretores de GnRH e dos neurônios olfatórios formam a base clínico-patológica da síndrome de Kallmann. Mutações nos genes KAL1, FGFR1/FGF8, PROK2/PROKR2, NELF, CHD7, HS6ST1 e WDR11 foram associadas a defeitos de migração neuronal, causando a síndrome de Kallmann. É notável que defeitos nos genes FGFR1, FGF8, PROKR2, CHD7 e WDR11 foram também associados ao HHI sem alterações olfatórias (HHI normósmico), porém em menor frequência. Adicionalmente, defeitos nos KISS1R, TAC3/TACR3 e GNRH1/GNRHR foram descritos exclusivamente em pacientes com HHI normósmico. Neste trabalho, revisaremos as características clínicas, hormonais e genéticas do HHI.
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Quaynor SD, Kim HG, Cappello EM, Williams T, Chorich LP, Bick DP, Sherins RJ, Layman LC. The prevalence of digenic mutations in patients with normosmic hypogonadotropic hypogonadism and Kallmann syndrome. Fertil Steril 2011; 96:1424-1430.e6. [PMID: 22035731 DOI: 10.1016/j.fertnstert.2011.09.046] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 09/20/2011] [Accepted: 09/23/2011] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To determine the prevalence of digenic mutations in patients with idiopathic hypogonadotropic hypogonadism (IHH) and Kallmann syndrome (KS). DESIGN Molecular analysis of DNA in IHH/KS patients. SETTING Academic medical center. PATIENT(S) Twenty-four IHH/KS patients with a known mutation (group 1) and 24 IHH/KS patients with no known mutation (group 2). INTERVENTION(S) DNA from IHH/KS patients was subjected to polymerase chain reaction-based DNA sequencing of the 13 most common genes (KAL1, GNRHR, FGFR1, KISS1R, TAC3, TACR3, FGF8, PROKR2, PROK2, CHD7, NELF, GNRH1, and WDR11). MAIN OUTCOME MEASURE(S) The identification of mutations absent in ≥188 ethnically matched controls. Both SIFT (sorting intolerant from tolerant) and conservation among orthologs provided supportive evidence for pathologic roles. RESULT(S) In group 1, 6 (25%) of 24 IHH/KS patients had a heterozygous mutation in a second gene, and in group 2, 13 (54.2%) of 24 had a mutation in at least one gene, but none had digenic mutations. In group 2, 7 (29.2%) of 24 had a mutation considered sufficient to cause the phenotype. CONCLUSION(S) When the 13 most common IHH/KS genes are studied, the overall prevalence of digenic gene mutations in IHH/KS was 12.5%. In addition, approximately 30% of patients without a known mutation had a mutation in a single gene. With the current state of knowledge, these findings suggest that most IHH/KS patients have a monogenic etiology.
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Affiliation(s)
- Samuel D Quaynor
- Section of Reproductive Endocrinology, Infertility, and Genetics, Department of Obstetrics and Gynecology, Institute of Molecular Medicine and Genetics, Neuroscience Program, Georgia Health Sciences University, Augusta, Georgia 30912, USA
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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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65
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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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66
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Murcia-Belmonte V, Esteban PF, García-González D, De Castro F. Biochemical dissection of Anosmin-1 interaction with FGFR1 and components of the extracellular matrix. J Neurochem 2010; 115:1256-65. [PMID: 20874775 DOI: 10.1111/j.1471-4159.2010.07024.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Anosmin-1, defective in Kallmann's syndrome, participates in the adhesion, migration and differentiation of different cell types in the CNS. Although not fully understood, the mechanisms of action of Anosmin-1 involve the interaction with different proteins, being the interaction with fibroblast growth factor receptor 1 (FGFR1) and the modulation of its signalling the best studied to date. Using glutathione-S-transferase pull-down assays we demonstrate that the FnIII.3 (Fibronectin-like type III) domain and the combination whey acidic protein-FnIII.1, but not each of them individually, interact with FGFR1. The interaction of the whey acidic protein-FnIII.1 domains is substantially reduced when the cysteine-rich region is present, suggesting a likely regulatory role for this domain. The introduction in FnIII.3 of any of the two missense mutations found in Kallmann's syndrome patients, E514K and F517L, abolished the interaction with FGFR1, what suggests an important role for these residues in the interaction. Interestingly, the chemoattraction of Anosmin-1 on rat neuronal precursors (NPs) via FGFR1 is retained by the N-terminal region of Anosmin-1 but not by FnIII.3 alone, and is lost in proteins carrying either one of the missense mutations, probably because of a highly reduced binding capacity to FGFR1. We also describe homophilic interaction Anosmin-1/Anosmin-1 via the FnIII repeats 1 and 4, and the interaction of FnIII.1 and FnIII.3 with Fibronectin and of FnIII.3 with Laminin.
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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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Zhu H, Duchesne L, Rudland PS, Fernig DG. The heparan sulfate co-receptor and the concentration of fibroblast growth factor-2 independently elicit different signalling patterns from the fibroblast growth factor receptor. Cell Commun Signal 2010; 8:14. [PMID: 20576134 PMCID: PMC2912315 DOI: 10.1186/1478-811x-8-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 06/24/2010] [Indexed: 01/12/2023] Open
Abstract
Background The fibroblast growth factor receptor (FGFR) interprets concentration gradients of FGF ligands and structural changes in the heparan sulfate (HS) co-receptor to generate different cellular responses. However, whether the FGFR generates different signals is not known. Results We have previously shown in rat mammary fibroblasts that in cells deficient in sulfation, and so in HS co-receptor, FGF-2 can only stimulate a transient phosphorylation of p42/44 MAPK and so cannot stimulate DNA synthesis. Here we demonstrate that this is because in the absence of HS, FGF-2 fails to stimulate the phosphorylation of the adaptor FGFR substrate 2 (FRS2). In cells possessing the HS co-receptor, FGF-2 elicits a bell-shaped dose response: optimal concentrations stimulate DNA synthesis, but supramaximal concentrations (≥ 100 ng/mL) have little effect. At optimal concentrations (300 pg/mL) FGF-2 stimulates a sustained dual phosphorylation of p42/44 MAPK and tyrosine phosphorylation of FRS2. In contrast, 100 ng/mL FGF-2 only stimulates a transient early peak of p42/44 MAPK phosphorylation and fails to stimulate appreciably the phosphorylation of FRS2 on tyrosine. Conclusions These results suggest that the nature of the FGFR signal produced is determined by a combination of the HS co-receptor and the concentration of FGF ligand. Both the phosphorylation of the adaptor FRS2, the kinetics (sustained or transient) of phosphorylation of p42/44(MAPK) are varied, and so differing cellular responses are produced.
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Affiliation(s)
- Hongyan Zhu
- School of Biological Sciences, Biosciences Building, Crown Street, University of Liverpool, Liverpool, L69 7ZB, UK.
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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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70
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Zohar Y, Muñoz-Cueto JA, Elizur A, Kah O. Neuroendocrinology of reproduction in teleost fish. Gen Comp Endocrinol 2010; 165:438-55. [PMID: 19393655 DOI: 10.1016/j.ygcen.2009.04.017] [Citation(s) in RCA: 506] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 04/08/2009] [Accepted: 04/17/2009] [Indexed: 11/28/2022]
Abstract
This review aims at synthesizing the most relevant information regarding the neuroendocrine circuits controlling reproduction, mainly gonadotropin release, in teleost fish. In teleosts, the pituitary receives a more or less direct innervation by neurons sending projections to the vicinity of the pituitary gonadotrophs. Among the neurotransmitters and neuropeptides released by these nerve endings are gonadotrophin-releasing hormones (GnRH) and dopamine, acting as stimulatory and inhibitory factors (in many but not all fish) on the liberation of LH and to a lesser extent that of FSH. The activity of the corresponding neurons depends on a complex interplay between external and internal factors that will ultimately influence the triggering of puberty and sexual maturation. Among these factors are sex steroids and other peripheral hormones and growth factors, but little is known regarding their targets. However, very recently a new actor has entered the field of reproductive physiology. KiSS1, first known as a tumor suppressor called metastin, and its receptor GPR54, are now central to the regulation of GnRH, and consequently LH and FSH secretion in mammals. The KiSS system is notably viewed as instrumental in integrating both environmental cues and metabolic signals and passing this information onto the reproductive axis. In fish, there are two KiSS genes, KiSS1 and KiSS2, expressed in neurons of the preoptic area and mediobasal hypothalamus. Pionneer studies indicate that KiSS and GPR54 expression seem to be activated at puberty. Although precise information as to the physiological effects of KiSS1 in fish, notably on GnRH neurons and gonadotropin release, is still limited, KiSS neurons may emerge as the "gatekeeper" of puberty and reproduction in fish as in mammals.
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Affiliation(s)
- Yonathan Zohar
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, MD, USA
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71
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García-González D, Clemente D, Coelho M, Esteban PF, Soussi-Yanicostas N, de Castro F. Dynamic roles of FGF-2 and Anosmin-1 in the migration of neuronal precursors from the subventricular zone during pre- and postnatal development. Exp Neurol 2010; 222:285-95. [PMID: 20083104 DOI: 10.1016/j.expneurol.2010.01.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 12/18/2009] [Accepted: 01/10/2010] [Indexed: 10/20/2022]
Abstract
FGF-2 and Anosmin-1 are diffusible proteins which act in cell proliferation and/or migration during CNS development. We describe their developmental expression patterns in the subventricular zone (SVZ) of the forebrain and the neuronal precursors (NPs) that migrate from this neurogenic site towards the olfactory bulb, forming the rostral migratory stream (RMS). The analysis is carried out before (E14), during (E17, P5) and after (P15) the peaks of migration along the RMS and before this acquires its mature conformation. At all these stages, FGF-2 exerts a FGFR1-mediated motogenic effect on NPs and induces the proliferation of SVZ astrocytes (putatively type B cells from triads), and Anosmin-1 works as a typical chemotropic agent for the NPs (mediated by FGFR1 at P5-P15). Altogether, our results are consistent with the notion that FGF-2 increases cell proliferation in the SVZ and would be the motogenic cue which feeds the migration of the newly produced NPs once generated, from early development (E14) and at least until P15, while Anosmin-1 cooperates in this migration attracting the NPs. In this sense, both cues should be considered as two of the first to be chronologically identified as actors in the formation of the RMS.
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Affiliation(s)
- Diego García-González
- Grupo de Neurobiología del Desarrollo-GNDe, Unidad de Neurología Experimental, Hospital Nacional de Parapléjicos, Finca La Peraleda s/n, E-45071-Toledo, Spain
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72
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Balasubramanian R, Dwyer A, Seminara SB, Pitteloud N, Kaiser UB, Crowley WF. Human GnRH deficiency: a unique disease model to unravel the ontogeny of GnRH neurons. Neuroendocrinology 2010; 92:81-99. [PMID: 20606386 PMCID: PMC3214927 DOI: 10.1159/000314193] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 04/21/2010] [Indexed: 11/19/2022]
Abstract
Evolutionary survival of a species is largely a function of its reproductive fitness. In mammals, a sparsely populated and widely dispersed network of hypothalamic neurons, the gonadotropin-releasing hormone (GnRH) neurons, serve as the pilot light of reproduction via coordinated secretion of GnRH. Since it first description, human GnRH deficiency has been recognized both clinically and genetically as a heterogeneous disease. A spectrum of different reproductive phenotypes comprised of congenital GnRH deficiency with anosmia (Kallmann syndrome), congenital GnRH deficiency with normal olfaction (normosmic idiopathic hypogonadotropic hypogonadism), and adult-onset hypogonadotropic hypogonadism has been described. In the last two decades, several genes and pathways which govern GnRH ontogeny have been discovered by studying humans with GnRH deficiency. More importantly, detailed study of these patients has highlighted the emerging theme of oligogenicity and genotypic synergism, and also expanded the phenotypic diversity with the documentation of reversal of GnRH deficiency later in adulthood in some patients. The underlying genetic defect has also helped understand the associated nonreproductive phenotypes seen in some of these patients. These insights now provide practicing clinicians with targeted genetic diagnostic strategies and also impact on clinical management.
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MESH Headings
- Animals
- Extracellular Matrix Proteins/deficiency
- Extracellular Matrix Proteins/genetics
- Female
- Fibroblast Growth Factors/genetics
- Fibroblast Growth Factors/metabolism
- Gastrointestinal Hormones/genetics
- Gastrointestinal Hormones/metabolism
- Gonadotropin-Releasing Hormone/deficiency
- Gonadotropin-Releasing Hormone/genetics
- Humans
- Hypogonadism/genetics
- Hypothalamus/growth & development
- Kallmann Syndrome/genetics
- Male
- Mice
- Nerve Tissue Proteins/deficiency
- Nerve Tissue Proteins/genetics
- Neuropeptides/genetics
- Neuropeptides/metabolism
- Olfaction Disorders/genetics
- Phenotype
- Receptors, G-Protein-Coupled/deficiency
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Kisspeptin-1
- Receptors, LHRH/genetics
- Receptors, LHRH/metabolism
- Receptors, Neurokinin-3/genetics
- Receptors, Neurokinin-3/metabolism
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism
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Affiliation(s)
| | | | | | | | | | - William F. Crowley
- *William F. Crowley, Jr., Harvard Reproductive Endocrine Sciences Center of Excellence, Massachusetts General Hospital, Bartlett Hall Extension 5th Floor, 55, Fruit Street, Boston, MA 02114 (USA), Tel. +1 617 726 5390, Fax +1 617 726 5357, E-Mail
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Yanicostas C, Herbomel E, Dipietromaria A, Soussi-Yanicostas N. Anosmin-1a is required for fasciculation and terminal targeting of olfactory sensory neuron axons in the zebrafish olfactory system. Mol Cell Endocrinol 2009; 312:53-60. [PMID: 19464344 DOI: 10.1016/j.mce.2009.04.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 04/10/2009] [Accepted: 04/17/2009] [Indexed: 11/30/2022]
Abstract
The KAL-1 gene underlies the X-linked form of Kallmann syndrome (KS), a neurological disorder that impairs the development of the olfactory and GnRH systems. KAL-1 encodes anosmin-1, a cell matrix protein that shows cell adhesion, neurite outgrowth, and axon-guidance and -branching activities. We used zebrafish embryos as model to better understand the role of this protein during olfactory system (OS) development. First, we detected the protein in olfactory sensory neurons from 22 h post-fertilization (hpf) onward, i.e. prior their pioneer axons reached presumptive olfactory bulbs (OBs). We found that anosmin-1a depletion impaired the fasciculation of olfactory axons and their terminal targeting within OBs. Last, we showed that kal1a inactivation induced a severe decrease in the number of GABAergic and dopaminergic OB neurons. Though the phenotypes induced following anosmin-1a depletion in zebrafish embryos did not match precisely the defects observed in KS patients, our results provide the first demonstration of a direct requirement for anosmin-1 in OS development in vertebrates and stress the role of OB innervation on OB neuron differentiation.
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Affiliation(s)
- Constantin Yanicostas
- Centre de Recherche de l'Institut du Cerveau et de la Moëlle épinière, Paris, France
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74
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Hu Y, Guimond SE, Travers P, Cadman S, Hohenester E, Turnbull JE, Kim SH, Bouloux PM. Novel mechanisms of fibroblast growth factor receptor 1 regulation by extracellular matrix protein anosmin-1. J Biol Chem 2009; 284:29905-20. [PMID: 19696444 DOI: 10.1074/jbc.m109.049155] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of fibroblast growth factor (FGF) signaling is initiated by a multiprotein complex formation between FGF, FGF receptor (FGFR), and heparan sulfate proteoglycan on the cell membrane. Cross-talk with other factors could affect this complex assembly and modulate the biological response of cells to FGF. We have previously demonstrated that anosmin-1, a glycosylated extracellular matrix protein, interacts with the FGFR1 signaling complex and enhances its activity in an IIIc isoform-specific and HS-dependent manner. The molecular mechanism of anosmin-1 action on FGFR1 signaling, however, remains unknown. Here, we show that anosmin-1 directly binds to FGFR1 with high affinity. This interaction involves domains in the N terminus of anosmin-1 (cysteine-rich region, whey acidic protein-like domain and the first fibronectin type III domain) and the D2-D3 extracellular domains of FGFR1. In contrast, anosmin-1 binds to FGFR2IIIc with much lower affinity and displays negligible binding to FGFR3IIIc. We also show that FGFR1-bound anosmin-1, although capable of binding to FGF2 alone, cannot bind to a FGF2.heparin complex, thus preventing FGFR1.FGF2.heparin complex formation. By contrast, heparin-bound anosmin-1 binds to pre-formed FGF2.FGFR1 complex, generating an anosmin-1.FGFR1.FGF2.heparin complex. Furthermore, a functional interaction between anosmin-1 and the FGFR1 signaling complex is demonstrated by immunofluorescence co-localization and Transwell migration assays where anosmin-1 was shown to induce opposing effects during chemotaxis of human neuronal cells. Our study provides molecular and cellular evidence for a modulatory action of anosmin-1 on FGFR1 signaling, whereby binding of anosmin-1 to FGFR1 and heparin can play a dual role in assembly and activity of the ternary FGFR1.FGF2.heparin complex.
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Affiliation(s)
- Youli Hu
- Centre for Neuroendocrinology, University College London Medical School, Royal Free Campus, London NW32PF.
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75
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Polanska UM, Fernig DG, Kinnunen T. Extracellular interactome of the FGF receptor-ligand system: complexities and the relative simplicity of the worm. Dev Dyn 2009; 238:277-93. [PMID: 18985724 DOI: 10.1002/dvdy.21757] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Fibroblast growth factors (FGFs) and their receptors (FGFRs) regulate a multitude of biological functions in embryonic development and in adult. A major question is how does one family of growth factors and their receptors control such a variety of functions? Classically, specificity was thought to be imparted by alternative splicing of the FGFRs, resulting in isoforms that bind specifically to a subset of the FGFs, and by different saccharide sequences in the heparan sulfate proteoglycan (HSPG) co-receptor. A growing number of noncanonical co-receptors such as integrins and neural cell adhesion molecule (NCAM) are now recognized as imparting additional complexity to classic FGFR signaling. This review will discuss the noncanonical FGFR ligands and speculate on the possibility that they provide additional and alternative means to determining the functional specificity of FGFR signaling. We will also discuss how invertebrate models such as C. elegans may advance our understanding of noncanonical FGFR signaling.
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Affiliation(s)
- Urszula M Polanska
- School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom
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76
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Bribián A, Esteban PF, Clemente D, Soussi-Yanicostas N, Thomas JL, Zalc B, de Castro F. A novel role for anosmin-1 in the adhesion and migration of oligodendrocyte precursors. Dev Neurobiol 2009; 68:1503-16. [PMID: 18814310 DOI: 10.1002/dneu.20678] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
At embryonic stages of development, oligodendrocyte precursors (OPCs) generated in the preoptic area colonize the entire optic nerve (ON). Different factors controlling migration of ON OPCs have been identified, including secreted growth factors, morphogens and guidance cues, as well as cell adhesion molecules. We have shown previously that the soluble form of the extracellular matrix (ECM) protein anosmin-1, impairs OPC migration induced by FGF-2. In the present work, we show that anosmin-1 is expressed by both migrating OPCs and axons of the retinal ganglion cells in the embryonic ON. In vitro, we observe that OPC migration is strongly impaired by contact with anosmin-1 when used as a substrate and, in contrast to previous results, this effect is independent of FGF-2/FGFR1 signaling. We also show that OPCs preferentially adhere to anosmin-1 when compared with other ECM molecules used as substrates, and that when the endogenous anosmin-1 expressed by OPCs is blocked, OPC adhesion to all the different substrates (including anosmin-1), is significantly reduced. This novel effect of anosmin-1 on cell adhesion is also independent of FGF-2/FGFR1. We finally demonstrate that the blockade of the endogenous anosmin-1 expressed by OPCs impairs their migration. Our data suggest that the endogenous anosmin-1 expressed by OPCs is necessary for the correct adhesion of these cells to the different components of the ECM (including anosmin-1 itself), contributing to the migration of these cells.
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Affiliation(s)
- Ana Bribián
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos, Finca La Peraleda s/n, Toledo E-45071, Spain
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77
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Morelli A, Fibbi B, Marini M, Silvestrini E, De Vita G, Chavalmane AK, Vignozzi L, Filippi S, Forti G, Vannelli GB, Maggi M. Dihydrotestosterone and Leptin Regulate Gonadotropin-Releasing Hormone (GnRH) Expression and Secretion in Human GnRH-Secreting Neuroblasts. J Sex Med 2009; 6:397-407. [DOI: 10.1111/j.1743-6109.2008.01084.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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78
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Gianola S, de Castro F, Rossi F. Anosmin-1 stimulates outgrowth and branching of developing Purkinje axons. Neuroscience 2008; 158:570-84. [PMID: 19013504 DOI: 10.1016/j.neuroscience.2008.10.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 10/12/2008] [Accepted: 10/15/2008] [Indexed: 11/19/2022]
Abstract
During development, Purkinje axons elongate along precise trajectories and acquire stereotypic branching patterns to innervate targets in the deep nuclei and cerebellar cortex. These processes are accomplished through cell-intrinsic mechanisms, whose operation is regulated by environmental signaling cues. Here, we show that Anosmin-1, the protein defective in the X-linked form of Kallmann syndrome, is one among such cues. Anosmin-1, that stimulates axon elongation and branching in the olfactory system, is expressed by Purkinje cells and deep nuclear neurons of the rat cerebellum during the ontogenetic period when Purkinje axons acquire their mature pattern. These neurons also express the putative Anosmin-1 receptor, fibroblast growth factor receptor 1. Application of Anosmin-1 to dissociated cultures of embryonic (embryonic day 17, E17) or postnatal (postnatal day 0, P0) rat cerebellar cells enhances neuritic elongation and exerts a strong promoting action on the budding of collateral branches and on the extension of terminal arbors. Opposite effects are observed when neutralizing anti-Anosmin-1 antibodies are applied to the same cultures. Comparable results are obtained by administering the protein or the blocking antibodies to organotypic cultures of postnatal (P0) rat cerebellum. In P10 cerebellar slices, Anosmin-1 does not enhance the spontaneous regenerative capabilities of severed Purkinje axons, but promotes the terminal outgrowth of injured neurites into embryonic neocortical explants apposed to the axotomy site. Although Anosmin-1 is unable to change the overall intrinsic growth competence of Purkinje cells, it exerts a powerful stimulatory action on the budding and extension of collateral branches and terminal plexus, contributing to the patterning of Purkinje axons.
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Affiliation(s)
- S Gianola
- Department of Neuroscience and "Rita Levi Montalcini Centre for Brain Repair," Section of Physiology, National Institute of Neuroscience, University of Turin, Corso Raffaello, 30, I-10125 Turin, Italy
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79
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Concolino D, Muzzi G, Pisaturo L, Piccirillo A, Di Natale P, Strisciuglio P. Precocious puberty in Sanfilippo IIIA disease: Diagnosis and follow-up of two new cases. Eur J Med Genet 2008; 51:466-71. [DOI: 10.1016/j.ejmg.2008.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Accepted: 05/04/2008] [Indexed: 10/22/2022]
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80
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Clemente D, Esteban PF, Del Valle I, Bribián A, Soussi-Yanicostas N, Silva A, De Castro F. Expression pattern of Anosmin-1 during pre- and postnatal rat brain development. Dev Dyn 2008; 237:2518-28. [DOI: 10.1002/dvdy.21659] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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81
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Morelli A, Marini M, Mancina R, Luconi M, Vignozzi L, Fibbi B, Filippi S, Pezzatini A, Forti G, Vannelli GB, Maggi M. Sex Steroids and Leptin Regulate the “First Kiss” (KiSS 1/G-Protein-Coupled Receptor 54 System) in Human Gonadotropin-Releasing-Hormone-Secreting Neuroblasts. J Sex Med 2008; 5:1097-1113. [DOI: 10.1111/j.1743-6109.2008.00782.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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82
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Cotton LM, O'Bryan MK, Hinton BT. Cellular signaling by fibroblast growth factors (FGFs) and their receptors (FGFRs) in male reproduction. Endocr Rev 2008; 29:193-216. [PMID: 18216218 PMCID: PMC2528845 DOI: 10.1210/er.2007-0028] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 11/29/2007] [Indexed: 12/25/2022]
Abstract
The major function of the reproductive system is to ensure the survival of the species by passing on hereditary traits from one generation to the next. This is accomplished through the production of gametes and the generation of hormones that function in the maturation and regulation of the reproductive system. It is well established that normal development and function of the male reproductive system is mediated by endocrine and paracrine signaling pathways. Fibroblast growth factors (FGFs), their receptors (FGFRs), and signaling cascades have been implicated in a diverse range of cellular processes including: proliferation, apoptosis, cell survival, chemotaxis, cell adhesion, motility, and differentiation. The maintenance and regulation of correct FGF signaling is evident from human and mouse genetic studies which demonstrate that mutations leading to disruption of FGF signaling cause a variety of developmental disorders including dominant skeletal diseases, infertility, and cancer. Over the course of this review, we will provide evidence for differential expression of FGFs/FGFRs in the testis, male germ cells, the epididymis, the seminal vesicle, and the prostate. We will show that this signaling cascade has an important role in sperm development and maturation. Furthermore, we will demonstrate that FGF/FGFR signaling is essential for normal epididymal function and prostate development. To this end, we will provide evidence for the involvement of the FGF signaling system in the regulation and maintenance of the male reproductive system.
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Affiliation(s)
- Leanne M Cotton
- Department of Cell Biology, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA
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83
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Salenave S, Chanson P, Bry H, Pugeat M, Cabrol S, Carel JC, Murat A, Lecomte P, Brailly S, Hardelin JP, Dodé C, Young J. Kallmann's syndrome: a comparison of the reproductive phenotypes in men carrying KAL1 and FGFR1/KAL2 mutations. J Clin Endocrinol Metab 2008; 93:758-63. [PMID: 18160472 DOI: 10.1210/jc.2007-1168] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Kallmann's syndrome (KS) is a genetically heterogeneous disorder consisting of congenital hypogonadotropic hypogonadism (CHH) with anosmia or hyposmia. OBJECTIVE Our objective was to compare the reproductive phenotypes of men harboring KAL1 and FGFR1/KAL2 mutations. DESIGN AND PATIENTS We studied the endocrine features reflecting gonadotropic-testicular axis function in 39 men; 21 had mutations in KAL1 and 18 in FGFR1/KAL2, but none had additional mutations in PROK-2 or PROKR-2 genes. RESULTS Puberty failed to occur in the patients with KAL1 mutations, all of whom had complete CHH. Three patients with FGFR1/KAL2 mutations had normal puberty, were eugonadal, and had normal testosterone and gonadotropin levels. Cryptorchidism was more frequent (14 of 21 vs. 3 of 15; P<00.1) and testicular volume (2.4+/-1.1 vs. 5.4+/-2.4 ml; P<0.001) was smaller in CHH subjects with KAL1 mutations than in subjects with FGFR1/KAL2 mutations. The mean basal plasma FSH level (0.72+/-0.47 vs. 1.48+/-0.62 IU/liter; P<0.05), serum inhibin B level (19.3+/-10.6 vs. 39.5+/-19.3 pg/ml; P<0.005), basal LH plasma level (0.57+/-0.54 vs. 1.0+/-0.6 IU/liter; P<0.01), and GnRH-stimulated LH plasma level (1.2+/-1.0 vs. 4.1+/-3.5 IU/liter; P<0.01) were significantly lower in the subjects with KAL1 mutations. LH pulsatility was studied in 13 CHH subjects with KAL1 mutations and seven subjects with FGFR1/KAL2 mutations; LH secretion was nonpulsatile in all the subjects, but mean LH levels were lower in those with KAL1 mutations. CONCLUSION KAL1 mutations result in a more severe reproductive phenotype than FGFR1/KAL2 mutations. The latter are associated with a broader spectrum of pubertal development and with less severe impairment of gonadotropin secretion.
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Affiliation(s)
- Sylvie Salenave
- Assistance Publique-Hôpitaux de Paris, and Univ Paris-Sud, France
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84
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Leroy C, Fouveaut C, Leclercq S, Jacquemont S, Boullay HD, Lespinasse J, Delpech M, Dupont JM, Hardelin JP, Dodé C. Biallelic mutations in the prokineticin-2 gene in two sporadic cases of Kallmann syndrome. Eur J Hum Genet 2008; 16:865-8. [DOI: 10.1038/ejhg.2008.15] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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85
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Ribeiro RS, Abucham J. Síndrome de Kallmann: uma revisão histórica, clínica e molecular. ACTA ACUST UNITED AC 2008; 52:8-17. [DOI: 10.1590/s0004-27302008000100004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 08/03/2007] [Indexed: 02/04/2023]
Abstract
A síndrome de Kallmann (SK) é a associação de hipogonadismo hipogonadotrófico (HH) e anosmia descrita por Maestre de San Juan, em 1856, e caracterizada como condição hereditária por Franz Josef Kallmann, em 1944. Muitos aspectos de sua patogenia, variabilidade fenotípica e genotípica foram desvendados nos últimos 15 anos. Conseqüentemente, tem sido difícil manter-se atualizado frente à rapidez que o conhecimento dessa condição é gerado. Nesta revisão, resgatamos aspectos históricos pouco conhecidos sobre a síndrome e seus descobridores; incorporamos novas descobertas relacionadas à embriogênese dos neurônios olfatórios e produtores de GnRH. Esse processo é fundamental para compreender a associação de hipogonadismo e anosmia; descrevemos a heterogeneidade fenotípica e genotípica, incluindo mutações em cinco genes (KAL-1, FGFR1, PROKR2, PROK2 e NELF). Para cada gene, discutimos a função da proteína codificada na migração e maturação dos neurônios olfatórios e GnRH a partir de estudos in vitro e modelos experimentais e descrevemos características clínicas dos portadores dessas mutações.
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86
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Kim SH, Hu Y, Cadman S, Bouloux P. Diversity in fibroblast growth factor receptor 1 regulation: learning from the investigation of Kallmann syndrome. J Neuroendocrinol 2008; 20:141-63. [PMID: 18034870 DOI: 10.1111/j.1365-2826.2007.01627.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The unravelling of the genetic basis of the hypogonadotrophic hypogonadal disorders, including Kallmann syndrome (KS), has led to renewed interest into the developmental biology of gonadotrophin-releasing hormone (GnRH) neurones and, more generally, into the molecular mechanisms of reproduction. KS is characterised by the association of GnRH deficiency with diminished olfaction. Until recently, only two KS-associated genes were known: KAL1 and KAL2. KAL1 encodes the cell membrane and extracellular matrix-associated secreted protein anosmin-1 which is implicated in the X-linked form of KS. Anosmin-1 shows high affinity binding to heparan sulphate (HS) and its function remains the focus of ongoing investigation, although a role in axonal guidance and neuronal migration, which are processes essential for normal GnRH ontogeny and olfactory bulb histogenesis, has been suggested. KAL2, identified as the fibroblast growth factor receptor 1 (FGFR1) gene, has now been recognised to be the underlying genetic defect for an autosomal dominant form of KS. The diverse signalling pathways initiated upon FGFR activation can elicit pleiotropic cellular responses depending on the cellular context. Signalling through FGFR requires HS for receptor dimerisation and ligand binding. Current evidence supports a HS-dependent interaction between anosmin-1 and FGFR1, where anosmin-1 serves as a co-ligand activator enhancing the signal activity, the finer details of whose mechanism remain the subject of intense investigation. Recently, mutations in the genes encoding prokineticin 2 (PK2) and prokineticin receptor 2 (PKR2) were reported in a cohort of KS patients, further reinforcing the view of KS as a multigenic trait involving divergent pathways. Here, we review the historical and current understandings of KS and discuss the latest findings from the molecular and cellular studies of the KS-associated proteins, and describe the evidence that suggests convergence of several of these pathways during normal GnRH and olfactory neuronal ontogeny.
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Affiliation(s)
- S-H Kim
- Centre for Neuroendocrinology, Royal Free and University College Medical School, University College London, London, UK.
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87
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Cariboni A, Maggi R, Parnavelas JG. From nose to fertility: the long migratory journey of gonadotropin-releasing hormone neurons. Trends Neurosci 2007; 30:638-44. [PMID: 17981344 DOI: 10.1016/j.tins.2007.09.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 09/18/2007] [Accepted: 09/19/2007] [Indexed: 12/27/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) neurons, a small number of cells dispersed in the hypothalamic region of the basal forebrain, play an important role in reproductive function. These neurons originate in the nasal placode and migrate, first in the nasal compartment, then through the cribriform plate and finally through the basal forebrain, before they attain their positions in the hypothalamus. Their movement through changing molecular environments suggests that numerous factors are involved in different phases of their migration. In humans, failure of GnRH neurons to migrate normally results in delayed or absent pubertal maturation and infertility. Advances in genetic and molecular biologic techniques in this decade have allowed us to gain insights into several molecules that affect the migration of GnRH neurons and, consequently, play a role in the establishment and maintenance of reproductive function.
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Affiliation(s)
- Anna Cariboni
- Department of Endocrinology, Centre of Excellence on Neurodegenerative Diseases, University of Milan, Milan 20133, Italy
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88
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Rites of passage through puberty: a complex genetic ensemble. Proc Natl Acad Sci U S A 2007; 104:17247-8. [PMID: 17959785 DOI: 10.1073/pnas.0708636104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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89
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Yamanaka H, Obata K, Kobayashi K, Dai Y, Fukuoka T, Noguchi K. Activation of fibroblast growth factor receptor by axotomy, through downstream p38 in dorsal root ganglion, contributes to neuropathic pain. Neuroscience 2007; 150:202-11. [PMID: 17905520 DOI: 10.1016/j.neuroscience.2007.08.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2007] [Revised: 08/02/2007] [Accepted: 08/24/2007] [Indexed: 11/21/2022]
Abstract
The possible involvement of fibroblast growth factor receptor (FGFR) activation in the dorsal root ganglion (DRG) was examined following peripheral nerve injury in the rat. Ligation of the sciatic nerve down-regulated FGFR2, -3 and -4 mRNA; however, the expression of FGFR1 mRNA showed no change. Activation of FGFR was examined by immunohistochemistry using an antibody of the phosphorylated form of FGFR1-4. Ligation of the sciatic nerve produced phosphorylation of FGFR in the L4 and 5 DRG ipsilateral to the injury, starting at 3 days after the lesion and persisting for more than 30 days. Substantial activation of FGFR was observed, mainly in unmyelinated small DRG neurons that co-expressed phosphorylated p38 mitogen-activated protein kinase (MAPK). Continuous intrathecal infusion of the FGFR1 inhibitor, 3-[3-(2-carboxyethyl)-4-methylpyrrol-2-methylidenyl]-2-indolinone, reduced p38 MAPK phosphorylation in the DRG and pain-related behaviors in the partial sciatic nerve model rat without affecting on the activation of spinal glia cells (microglia and astrocyte). In the injured small DRG neurons, activation of FGFR1 may contribute to the generation of neuropathic pain by activating p38 MAPK.
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Affiliation(s)
- H Yamanaka
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
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90
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Xu N, Qin Y, Reindollar RH, Tho SPT, McDonough PG, Layman LC. A mutation in the fibroblast growth factor receptor 1 gene causes fully penetrant normosmic isolated hypogonadotropic hypogonadism. J Clin Endocrinol Metab 2007; 92:1155-8. [PMID: 17200176 DOI: 10.1210/jc.2006-1183] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Kallmann syndrome (KS) consists of idiopathic hypogonadotropic hypogonadism (IHH) and anosmia/hyposmia. Currently, the fibroblast growth factor receptor 1 (FGFR1) gene is the only known autosomal dominant cause of KS, which is also associated with synkinesia, midfacial defects, and dental agenesis. OBJECTIVE Mutations in FGFR1 typically demonstrate reduced penetrance, variable expressivity, and until recently have been exclusively identified in families with anosmia. The purpose of this study was to determine whether FGFR1 mutations were present in a unique family with autosomal dominant, fully penetrant, normosmic IHH. DESIGN The study is a review of detailed clinical findings, dynamic endocrine studies, and performance of a molecular analysis of the FGFR1 gene. SETTING The study was carried out in an academic medical center. PATIENTS All four affected individuals have complete IHH with full penetrance but no anosmia/hyposmia, and they have none of the FGFR1-associated anomalies. In addition, no other family member has anosmia. Inverventions: Interventions included detailed phenotype characterization including history, physical exam, smell testing, dynamic pituitary testing, brain imaging, and molecular analysis. MAIN OUTCOME MEASURES Outcome was measured by the determination of the severity of IHH, olfactory function, and sequence of the FGFR1 gene. RESULTS The same heterozygous nonsense mutation, Arg622X, was present in all four affected members, but not in three unaffected members or 100 controls. The mutation is predicted to encode a truncated protein or result in nonsense-mediated decay. CONCLUSIONS Our findings indicate that mutations in the FGFR1 gene can cause normosmic, fully penetrant, complete IHH with little or no variable expressivity, and without the other FGFR1-associated anomalies typically found in KS.
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Affiliation(s)
- Ning Xu
- Section of Reproductive Endocrinology, Infertility, and Genetics, Department of Obstetrics and Gynecology, The Medical College of Georgia, 1120 15th Street, Augusta, Georgia 30912-3360, USA
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91
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Pitteloud N, Quinton R, Pearce S, Raivio T, Acierno J, Dwyer A, Plummer L, Hughes V, Seminara S, Cheng YZ, Li WP, Maccoll G, Eliseenkova AV, Olsen SK, Ibrahimi OA, Hayes FJ, Boepple P, Hall JE, Bouloux P, Mohammadi M, Crowley W. Digenic mutations account for variable phenotypes in idiopathic hypogonadotropic hypogonadism. J Clin Invest 2007; 117:457-63. [PMID: 17235395 PMCID: PMC1765517 DOI: 10.1172/jci29884] [Citation(s) in RCA: 265] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 11/27/2006] [Indexed: 11/17/2022] Open
Abstract
Idiopathic hypogonadotropic hypogonadism (IHH) due to defects of gonadotropin-releasing hormone (GnRH) secretion and/or action is a developmental disorder of sexual maturation. To date, several single-gene defects have been implicated in the pathogenesis of IHH. However, significant inter- and intrafamilial variability and apparent incomplete penetrance in familial cases of IHH are difficult to reconcile with the model of a single-gene defect. We therefore hypothesized that mutations at different IHH loci interact in some families to modify their phenotypes. To address this issue, we studied 2 families, one with Kallmann syndrome (IHH and anosmia) and another with normosmic IHH, in which a single-gene defect had been identified: a heterozygous FGF receptor 1 (FGFR1) mutation in pedigree 1 and a compound heterozygous gonadotropin-releasing hormone receptor (GNRHR) mutation in pedigree 2, both of which varied markedly in expressivity within and across families. Further candidate gene screening revealed a second heterozygous deletion in the nasal embryonic LHRH factor (NELF) gene in pedigree 1 and an additional heterozygous FGFR1 mutation in pedigree 2 that accounted for the considerable phenotypic variability. Therefore, 2 different gene defects can synergize to produce a more severe phenotype in IHH families than either alone. This genetic model could account for some phenotypic heterogeneity seen in GnRH deficiency.
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MESH Headings
- Adult
- Amino Acid Sequence
- Base Sequence
- Conserved Sequence
- DNA/genetics
- Female
- Fibroblast Growth Factor 8/metabolism
- Genotype
- Gonadotropin-Releasing Hormone/deficiency
- Heterozygote
- Humans
- Hypogonadism/etiology
- Hypogonadism/genetics
- Hypogonadism/metabolism
- Kallmann Syndrome/genetics
- Male
- Models, Genetic
- Models, Molecular
- Molecular Sequence Data
- Mutation
- Pedigree
- Phenotype
- Receptor, Fibroblast Growth Factor, Type 1/chemistry
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/metabolism
- Receptors, LHRH/genetics
- Sequence Deletion
- Sequence Homology, Amino Acid
- Transcription Factors/genetics
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Affiliation(s)
- Nelly Pitteloud
- Reproductive Endocrine Unit of the Department of Medicine and Harvard Reproductive Endocrine Science Centers, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
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92
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Bhagavath B, Xu N, Ozata M, Rosenfield RL, Bick DP, Sherins RJ, Layman LC. KAL1 mutations are not a common cause of idiopathic hypogonadotrophic hypogonadism in humans. Mol Hum Reprod 2007; 13:165-70. [PMID: 17213338 DOI: 10.1093/molehr/gal108] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hypogonadotrophic hypogonadism results in the absence of puberty and if left untreated leads to infertility. Mutations in KAL1 are known to account for some of the cases of Kallmann syndrome. The aim of this study was to determine the prevalence of KAL1 mutations in a large number of patients with idiopathic hypogonadotrophic hypogonadism (IHH). One hundred and thirty eight patients (109 males and 29 females) with IHH were studied for mutations in KAL1. DNA from these patients was subjected to denaturing gradient gel electrophoresis or single strand conformation polymorphism to identify mutations. Sequencing was performed to confirm mutations detected. Four mutations were found in 109 males (3.7%). All four mutations were in anosmic/hyposmic men making the prevalence 4/63 (6.3%) in this group of patients. No mutations were found in the 29 female patients. KAL1 mutations are an uncommon cause of Kallmann syndrome.
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Affiliation(s)
- Balasubramanian Bhagavath
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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93
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Abstract
The identification of naturally occurring genetic mutations has provided unique insight into the current knowledge of the human hypothalamic-pituitary-gonadal axis. In the past decade, several monogenic causes have been reported in patients with isolated gonadotropin deficiency. Kallmann Syndrome is a clinically and genetically heterogeneous disorder, characterized by isolated hypogonadotropic hypogonadism and anosmia or hyposmia. To date, loss-of-function mutations in the genes encoding anosmin-1 (KAL1) and fibroblast growth factor receptor 1 (FGFR1) have been described in the X-linked and autosomal dominant forms of this syndrome, respectively. More recently, several heterozygous, homozygous or compound heterozygous mutations in the G protein-coupled prokineticin receptor-2 (PROKR2) and one of its ligands, prokineticin-2 (PROK2) were described in Kallmann syndrome. In addition, complex genetic transmission (digenic inheritance) was recently demonstrated in this condition. Regarding isolated hypogonadotropic hypogonadism without olfactory abnormalities, loss-of-function mutations in the Gonadotropin-releasing hormone (GnRH) receptor (GnRH-R) or the G-protein coupled receptor 54 (GPR54) genes, both encoding transmembrane receptors, have been described, as well as FGFR1 mutations. Finally, mutations of the beta sub-units of LH and FSH have been described in patients with selective gonadotropin deficiency. We review the role of these distinct genetic factors in human isolated hypogonadotropic hypogonadism.
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Affiliation(s)
- Ericka Barbosa Trarbach
- Developmental Endocrinology Unit, Hormone and Molecular Genetic Laboratory LIM/42, Clinical Hospital, São Paulo University Medical School, Sao Paulo 05403-900, Brazil
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94
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Cadman SM, Kim SH, Hu Y, González-Martínez D, Bouloux PM. Molecular pathogenesis of Kallmann's syndrome. HORMONE RESEARCH 2006; 67:231-42. [PMID: 17191030 DOI: 10.1159/000098156] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hypogonadotrophic hypogonadism (HH) is characterized by delayed or absent pubertal development secondary to gonadotrophin deficiency. HH can result from mutations of the gonadotrophin-releasing hormone receptor 1, the gonadotrophin beta-subunits, or various transcription factors involved in pituitary gland development. HH occurs in DAX1 mutations when associated with adrenal insufficiency (adrenal hypoplasia congenita), and is also linked with obesity in patients with mutations of leptin and its receptor, as well as mutations in prohormone convertase 1. Rarely, HH has resulted from kisspeptin receptor (GPR54) mutations, a gene implicated in the regulation of pubertal onset. When occurring with anosmia (a lack of sense of smell), HH is referred to as Kallmann's syndrome (KS). Two KS-related loci are currently known: KAL1, encoding anosmin-1, responsible for X-linked KS, and KAL2, encoding the fibroblast growth factor receptor 1 (FGFR1), mutated in autosomal dominant KS. Anosmin-1 is an extracellular glycoprotein with some unique structural characteristics; it interacts with both urokinase-type plasminogen activator and FGFR1. It has previously been shown that anosmin-1 enhances FGFR1 signalling in a heparan sulphate-dependent manner, and proposed that anosmin-1 fine-tunes FGFR1 signalling during olfactory and GnRH neuronal development. Here, we review the known normosmic causes of HH, and discuss novel developmental and molecular mechanisms underlying KS; finally, we introduce three novel genes (NELF, PKR2, and CHD7) that may be associated with some phenotypic features of KS.
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MESH Headings
- Extracellular Matrix Proteins/genetics
- Extracellular Matrix Proteins/physiology
- Genes, Dominant
- Genes, X-Linked
- Gonadotropin-Releasing Hormone/genetics
- Gonadotropin-Releasing Hormone/metabolism
- Gonadotropin-Releasing Hormone/physiology
- Heparan Sulfate Proteoglycans/physiology
- Humans
- Kallmann Syndrome/etiology
- Kallmann Syndrome/genetics
- Models, Biological
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/physiology
- Olfactory Bulb/embryology
- Olfactory Bulb/metabolism
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/physiology
- Receptors, LHRH/genetics
- Receptors, LHRH/metabolism
- Receptors, LHRH/physiology
- Signal Transduction
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Affiliation(s)
- Steven Mark Cadman
- Centre for Neuroendocrinology, Royal Free and University College Medical School, University College London, London, UK.
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95
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Cerrato F, Shagoury J, Kralickova M, Dwyer A, Falardeau J, Ozata M, Van Vliet G, Bouloux P, Hall JE, Hayes FJ, Pitteloud N, Martin KA, Welt C, Seminara SB. Coding sequence analysis of GNRHR and GPR54 in patients with congenital and adult-onset forms of hypogonadotropic hypogonadism. Eur J Endocrinol 2006; 155 Suppl 1:S3-S10. [PMID: 17074994 DOI: 10.1530/eje.1.02235] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To determine the frequency of rare nucleotide variants in GNRHR and GPR54 in a large cohort of probands (n = 166) with normosmic idiopathic hypogonadotropic hypogonadism (nIHH), characterized by mode of inheritance, testicular volume, and presence or absence of endogenous LH pulsations. METHODS Whenever possible, probands answered detailed questionnaires, underwent full physical exams, and underwent q 10-min frequent blood sampling for LH. Exons segments for GNRHR and GPR54 were screened for mutations. Nucleotide changes were identified as rare variants if they occurred at less than 1% frequency in an ethnically matched control population. RESULTS Sixty-two percent of male probands were classified as sporadic, meaning that no other family members had delayed puberty or nIHH. In contrast, 61% of female probands were from familial pedigrees, with either autosomal dominant or autosomal recessive inheritance. Patients displayed a broad spectrum of disease severity based on testicular size and endogenous LH pulsations. Twenty-four rare variants were identified in GNRHR (within 15 probands) and seven rare variants in GPR54 (within five probands). CONCLUSIONS Rare variants in GNRHR are more common than GPR54 in a nIHH population.
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Affiliation(s)
- Felecia Cerrato
- Reproductive Endocrine Unit, Massachusetts General Hospital BHX 504, Fruit Street, Boston, Massachusetts 02114, USA
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96
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Trarbach EB, Costa EMF, Versiani B, de Castro M, Baptista MTM, Garmes HM, de Mendonca BB, Latronico AC. Novel fibroblast growth factor receptor 1 mutations in patients with congenital hypogonadotropic hypogonadism with and without anosmia. J Clin Endocrinol Metab 2006; 91:4006-12. [PMID: 16882753 DOI: 10.1210/jc.2005-2793] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Kallmann syndrome is a clinically and genetically heterogeneous disorder. To date, loss-of-function mutations in the genes encoding anosmin-1 (KAL1) and fibroblast growth factor receptor 1 (FGFR1) have been described in the X-linked and autosomal dominant forms of this syndrome, respectively. OBJECTIVE The objective was to investigate genetic defects in the KAL1 and FGFR1 genes in patients with congenital isolated hypogonadotropic hypogonadism (IHH). PATIENTS Eighty patients (71 males and nine females) with IHH were studied, of which 30 were familial. Forty-six of them had olfactory abnormalities. METHODS The coding regions of both KAL1 and FGFR1 genes were amplified and automatically sequenced. The KAL1 mutations were investigated only in patients with olfactory abnormalities, whereas FGFR1 was studied in the entire group. RESULTS Two novel KAL1 mutations, an intragenic deletion of exons 3-6 and a splicing mutation IVS7 + 1G>A, were identified in two of 46 patients with Kallmann syndrome. Eight novel heterozygous FGFR1 mutations (G48S, L245P, R250W, A343V, P366L, K618fsX654, P722S, and V795I) were identified in nine of 80 patients with IHH. Eight of them had olfactory abnormalities. Interestingly, the G48S mutation was identified in a normosmic IHH patient. Two unrelated females, who carried FGFR1 mutations, had anosmia and normal reproductive function. CONCLUSION We identified novel mutations in KAL1 and FGFR1 genes in IHH patients. FGFR1 mutations were identified in 17% of the patients with olfactory abnormalities and in one of 34 normosmic IHH patients. In addition, isolated anosmia was identified in two unrelated females as a partial phenotypic manifestation of FGFR1 defects.
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Affiliation(s)
- Ericka Barbosa Trarbach
- Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, Disciplina de Endocrinologia e Metabologia, Av Dr Enéas de Carvalho Aguiar, 155 2o andar Bloco 6, 05403-900 São Paulo, Brazil.
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97
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Abstract
PURPOSE OF REVIEW Patients with advanced head and neck cancer are being treated with chemo-radiotherapy, and life is being prolonged, with or without persistent disease, for longer than was previously. Hypercalcaemia may present in patients with advanced or disseminated head and neck cancer, and, as such, these patients may present to a larger variety of clinicians for advice concerning their symptoms and illness. Modes of presentation of hypercalcaemia and treatment strategies are reviewed. RECENT FINDINGS There were previously few large series of head and neck cancer patients diagnosed with hypercalcaemia, which may or may not have been related to their cancer being treated. Investigations, by way of blood/serum calcium level, may identify such patients. Patients with cancer-related hypercalcaemia have a poor prognosis, but many may respond temporarily to treatment when offered, with an improvement of their quality of life and death. SUMMARY Hypercalcaemia should and must be considered in all patients who have or possibly have a diagnosis of a head and neck cancer and who present unwell with symptoms of fatigue, lethargy and somnolence. Investigation must include serum calcium (corrected for serum albumin binding) and parathyroid hormone level. Patients may be treated by a combination of rehydration and bisulphonate therapy until the serum calcium is reduced to a level below 3 mmol/l. The majority of patients diagnosed with hypercalcaemia due to head and neck malignancy die of their diseases in the short term, but some may enjoy a prolongation of life with reasonable quality if diagnosed and treated aggressively.
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Affiliation(s)
- Patrick J Bradley
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, University Hospital, Nottingham, UK.
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98
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Dodé C, Teixeira L, Levilliers J, Fouveaut C, Bouchard P, Kottler ML, Lespinasse J, Lienhardt-Roussie A, Mathieu M, Moerman A, Morgan G, Murat A, Toublanc JE, Wolczynski S, Delpech M, Petit C, Young J, Hardelin JP. Kallmann syndrome: mutations in the genes encoding prokineticin-2 and prokineticin receptor-2. PLoS Genet 2006; 2:e175. [PMID: 17054399 PMCID: PMC1617130 DOI: 10.1371/journal.pgen.0020175] [Citation(s) in RCA: 297] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Accepted: 08/31/2006] [Indexed: 01/24/2023] Open
Abstract
Kallmann syndrome combines anosmia, related to defective olfactory bulb morphogenesis, and hypogonadism due to gonadotropin-releasing hormone deficiency. Loss-of-function mutations in KAL1 and FGFR1 underlie the X chromosome-linked form and an autosomal dominant form of the disease, respectively. Mutations in these genes, however, only account for approximately 20% of all Kallmann syndrome cases. In a cohort of 192 patients we took a candidate gene strategy and identified ten and four different point mutations in the genes encoding the G protein-coupled prokineticin receptor-2 (PROKR2) and one of its ligands, prokineticin-2 (PROK2), respectively. The mutations in PROK2 were detected in the heterozygous state, whereas PROKR2 mutations were found in the heterozygous, homozygous, or compound heterozygous state. In addition, one of the patients heterozygous for a PROKR2 mutation was also carrying a missense mutation in KAL1, thus indicating a possible digenic inheritance of the disease in this individual. These findings reveal that insufficient prokineticin-signaling through PROKR2 leads to abnormal development of the olfactory system and reproductive axis in man. They also shed new light on the complex genetic transmission of Kallmann syndrome.
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Affiliation(s)
- Catherine Dodé
- Institut Cochin, INSERM U567, Université René Descartes, Paris, France
- * To whom correspondence should be addressed. E-mail: (CD), (JPH)
| | - Luis Teixeira
- Institut Cochin, INSERM U567, Université René Descartes, Paris, France
| | - Jacqueline Levilliers
- Unité de Génétique des Déficits Sensoriels, INSERM U587, Institut Pasteur, Paris, France
| | - Corinne Fouveaut
- Laboratoire de Biochimie Génétique, Hôpital Cochin, Paris, France
| | | | | | - James Lespinasse
- Laboratoire de Génétique Chromosomique, Centre Hospitalier, Chambéry, France
| | | | - Michèle Mathieu
- Département de Pédiatrie, Centre Hospitalier, Amiens, France
| | | | | | - Arnaud Murat
- Clinique d'Endocrinologie, Maladies Métaboliques et Nutrition, Hôtel-Dieu, Nantes, France
| | - Jean-Edmont Toublanc
- Service d'Endocrinologie Pédiatrique, Hôpital Saint-Vincent de Paul, Paris, France
| | - Slawomir Wolczynski
- Department of Reproduction and Gynecological Endocrinology, Bialystok, Poland
| | - Marc Delpech
- Institut Cochin, INSERM U567, Université René Descartes, Paris, France
| | - Christine Petit
- Unité de Génétique des Déficits Sensoriels, INSERM U587, Institut Pasteur, Paris, France
| | - Jacques Young
- Service d'Endocrinologie, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France
| | - Jean-Pierre Hardelin
- Unité de Génétique des Déficits Sensoriels, INSERM U587, Institut Pasteur, Paris, France
- * To whom correspondence should be addressed. E-mail: (CD), (JPH)
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99
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Bribián A, Barallobre MJ, Soussi-Yanicostas N, de Castro F. Anosmin-1 modulates the FGF-2-dependent migration of oligodendrocyte precursors in the developing optic nerve. Mol Cell Neurosci 2006; 33:2-14. [PMID: 16876430 DOI: 10.1016/j.mcn.2006.05.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 05/11/2006] [Accepted: 05/19/2006] [Indexed: 11/29/2022] Open
Abstract
Oligodendrocyte precursors (OPCs) originate at specific domains within the neural tube before migrating to colonize the entire CNS. Once in their target areas, these cells differentiate into oligodendrocytes, the myelin-forming cells in the CNS. Using the embryonic mouse optic nerve as an experimental model, we have analyzed the influence of FGF-2 on OPC development. FGF-2 exerts a dose-dependent motogenic effect on the migration of plp-dm20+ and it also acts as a chemoattractant on these cells. These effects produced by FGF-2 are principally mediated by the FGFR1 receptor, which is expressed by OPCs. Anosmin-1 is the protein that is defective in the X-linked form of human Kallmann syndrome. This protein is expressed by retinal axons and it also interacts with FGFR1, thereby impairing the migration of OPCs. Because both Anosmin-1 and FGF-2 are present in the optic nerve in vivo, we propose a model whereby the relative concentration of these two proteins modulates the migration of OPCs during development through their interaction with FGFR1. This FGF-2/FGFR1/Anosmin-1 system may be relevant in the context of demyelinating diseases.
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Affiliation(s)
- Ana Bribián
- Instituto de Neurociencias de Castilla y León-INCyL, Universidad de Salamanca, Avda. de Alfonso X el Sabio, s/n, E-37007-Salamanca, Spain
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100
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Zenaty D, Bretones P, Lambe C, Guemas I, David M, Léger J, de Roux N. Paediatric phenotype of Kallmann syndrome due to mutations of fibroblast growth factor receptor 1 (FGFR1). Mol Cell Endocrinol 2006; 254-255:78-83. [PMID: 16757108 DOI: 10.1016/j.mce.2006.04.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kallmann syndrome characterised by hypogonadotropic hypogonadism (HH) and anosmia is genetically heterogeneous with X-linked, autosomal dominant and autosomal recessive forms. The autosomal dominant form due to loss of function mutation in the fibroblast growth factor receptor 1 (FGFR1) accounts for about 10% of cases. We report here three paediatric cases of Kallmann syndrome with unusual phenotype in two unrelated patients with severe ear anomalies (hypoplasia or agenesis of external ear) associated with classical features, such as cleft palate, dental agenesis, syndactylia, micropenis and cryptorchidism. We found de novo mutation in these two patients (Cys178Ser and Arg622Gly, respectively), and one inherited Arg622Gln mutation with intrafamilial variable phenotype. These genotype-phenotype correlations indicate that paediatric phenotypic expression of FGFR1 loss of function mutations is highly variable, the severity of the oro-facial malformations at birth does not predict gonadotropic function at the puberty and that de novo mutations of FGFR1 are relatively frequent.
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Affiliation(s)
- Delphine Zenaty
- Assistance Publique Hôpitaux de Paris, Robert Debre Hospital Paediatric Endocrinology unit, Robert Debré Hospital, Paris, France
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