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Abstract
A healthy nutritional state is required for all aspects of reproduction and is signaled by the adipokine leptin. Leptin acts in a relatively narrow concentration range: too much or too little will compromise fertility. The leptin signal timing is important to prepubertal development in both sexes. In the brain, leptin acts on ventral premammillary neurons which signal kisspeptin (Kiss1) neurons to stimulate gonadotropin releasing hormone (GnRH) neurons. Suppression of Kiss1 neurons occurs when agouti-related peptide neurons are activated by reduced leptin, because leptin normally suppresses these orexigenic neurons. In the pituitary, leptin stimulates production of GnRH receptors (GnRHRs) and follicle-stimulating hormone at midcycle, by activating pathways that derepress actions of the messenger ribonucleic acid translational regulatory protein Musashi. In females, rising estrogen stimulates a rise in serum leptin, which peaks at midcycle, synchronizing with nocturnal luteinizing hormone pulses. The normal range of serum leptin levels (10-20 ng/mL) along with gonadotropins and growth factors promote ovarian granulosa and theca cell functions and oocyte maturation. In males, the prepubertal rise in leptin promotes testicular development. However, a decline in leptin levels in prepubertal boys reflects inhibition of leptin secretion by rising androgens. In adult males, leptin levels are 10% to 50% of those in females, and high leptin inhibits testicular function. The obesity epidemic has elucidated leptin resistance pathways, with too much leptin in either sex leading to infertility. Under conditions of balanced nutrition, however, the secretion of leptin is timed and regulated within a narrow level range that optimizes its trophic effects.
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Affiliation(s)
- Gwen V Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Correspondence: Gwen V. Childs, PhD, University of Arkansas for Medical Sciences, Little Rock, AR, USA. E-mail:
| | - Angela K Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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Odle AK, Beneš H, Melgar Castillo A, Akhter N, Syed M, Haney A, Allensworth-James M, Hardy L, Winter B, Manoharan R, Syed R, MacNicol MC, MacNicol AM, Childs GV. Association of Gnrhr mRNA With the Stem Cell Determinant Musashi: A Mechanism for Leptin-Mediated Modulation of GnRHR Expression. Endocrinology 2018; 159:883-894. [PMID: 29228137 PMCID: PMC5776477 DOI: 10.1210/en.2017-00586] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 12/01/2017] [Indexed: 12/30/2022]
Abstract
The cyclic expression of pituitary gonadotropin-releasing hormone receptors (GnRHRs) may be an important checkpoint for leptin regulatory signals. Gonadotrope Lepr-null mice have reduced GnRHR levels, suggesting these receptors may be leptin targets. To determine if leptin stimulated GnRHR directly, primary pituitary cultures or pieces were exposed to 1 to 100 nM leptin. Leptin increased GnRHR protein levels and the percentages of gonadotropes that bound biotinylated analogs of gonadotropin-releasing hormone (bio-GnRH) but had no effect on Gnrhr messenger RNA (mRNA). An in silico analysis revealed three consensus Musashi (MSI) binding elements (MBEs) for this translational control protein in the 3' untranslated region (UTR) of Gnrhr mRNA. Several experiments determined that these Gnrhr mRNA MBE were active: (1) RNA electrophoretic mobility shift assay analyses showed that MSI1 specifically bound Gnrhr mRNA 3'-UTR; (2) RNA immunoprecipitation of pituitary fractions with MSI1 antibody pulled down a complex enriched in endogenous MSI protein and endogenous Gnrhr mRNA; and (3) fluorescence reporter assays showed that MSI1 repressed translation of the reporter coupled to the Gnrhr 3'-UTR. In vitro, leptin stimulation of pituitary pieces reduced Msi1 mRNA in female pituitaries, and leptin stimulation of pituitary cultures reduced MSI1 proteins selectively in gonadotropes identified by binding to bio-GnRH. These findings show that leptin's direct stimulatory actions on gonadotrope GnRHR correlate with a direct inhibition of expression of the posttranscriptional regulator MSI1. We also show MSI1 interaction with the 3'-UTR of Gnrhr mRNA. These findings now open the door to future studies of leptin-modulated posttranscriptional pathways.
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Affiliation(s)
- Angela K. Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Helen Beneš
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Andrea Melgar Castillo
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Noor Akhter
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Mohsin Syed
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Anessa Haney
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Melody Allensworth-James
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Linda Hardy
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Benjamin Winter
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Ragul Manoharan
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Raiyan Syed
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Melanie C. MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Angus M. MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Gwen V. Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
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Bello AR, Puertas‐Avendaño RA, González‐Gómez MJ, González‐Gómez M, Laborda J, Damas C, Ruiz‐Hidalgo M, Diaz C. Delta-like protein 1 in the pituitary-adipose axis in the adult male mouse. J Neuroendocrinol 2017; 29:e12507. [PMID: 28718206 PMCID: PMC6084355 DOI: 10.1111/jne.12507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 06/21/2017] [Accepted: 07/12/2017] [Indexed: 12/18/2022]
Abstract
With the aim of studying delta-like protein 1 (DLK1) with respect to the relationship between adipocyte leptin and adenohypophyseal hormones, we carried out an immunohistochemical study analysing the presence of receptors for these hormones in the pituitary and adipose cells of male wild-type (WT) mice (Dlk1+/+ ) compared to knockout (KO) mice (Dlk1-/- ). The mRNA expression of these molecules was also determined using the reverse transcriptase-polymerase chain reaction. The results obtained showed that, in WT adipose cells, all of the adenohypophyseal hormone receptors were present, with a higher mRNA expression for growth hormone (GH) receptor and thyroid-stimulating hormone (TSH) receptor. Of the total cells in the anterior pituitary lobe, 17.09±0.9% were leptin receptor (LEPR) immunoreactive (-IR), mainly in GH-IR and prolactin (PRL)-IR cells (41.5±3.8%; 13.5±1.7%, respectively). In Dlk1-/- mice, adipocyte cells showed a significant increase in the TSH receptor mRNA expression level. Moreover, the percentage of LEPR-IR GH cells showed a statistically significant increase compared to controls, from 41.5±3.8% to 53.1±4.0%. By contrast, only 3.0±0.6% of LEP-IR anterior pituitary cells were detected in Dlk1 KO mice, as opposed to 6.8±1.1% observed in WT mice. The results suggest that relationships exist between adipocytes and pituitary GH, PRL and TSH cells, in addition to an influence with respect to the synthesis and release of pituitary leptin, particularly in PRL cells.
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Affiliation(s)
- A. R. Bello
- Cell Biology SectionSchool of Sciences/Institute for Tropical Diseases and Public HealthUniversity of La LagunaTenerifeSpain
| | - R. A. Puertas‐Avendaño
- Cell Biology SectionSchool of Sciences/Institute for Tropical Diseases and Public HealthUniversity of La LagunaTenerifeSpain
| | - M. J. González‐Gómez
- Department of Inorganic and Organic Chemistry and BiochemistrySchool of Medicine/Regional Centre for Biomedical ResearchBiomedicine Unit Spanish National Research Council/University of Castilla‐La ManchaAlbaceteSpain
| | - M. González‐Gómez
- Department of Basic Medical SciencesSchool of MedicineUniversity of La LagunaTenerifeSpain
| | - J. Laborda
- Department of Inorganic and Organic Chemistry and BiochemistrySchool of Medicine/Regional Centre for Biomedical ResearchBiomedicine Unit Spanish National Research Council/University of Castilla‐La ManchaAlbaceteSpain
| | - C. Damas
- Department of PsychobiologySchool of PsychologyUniversity of La LagunaTenerifeSpain
| | - M. Ruiz‐Hidalgo
- Department of Inorganic and Organic Chemistry and BiochemistrySchool of Medicine/Regional Centre for Biomedical ResearchBiomedicine Unit Spanish National Research Council/University of Castilla‐La ManchaAlbaceteSpain
| | - C. Diaz
- Department of Medical SciencesSchool of Medicine/Institute for Research in Neurological DisabilitiesUniversity of Castilla‐La ManchaAlbaceteSpain
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Sarmento-Cabral A, Peinado JR, Halliday LC, Malagon MM, Castaño JP, Kineman RD, Luque RM. Adipokines (Leptin, Adiponectin, Resistin) Differentially Regulate All Hormonal Cell Types in Primary Anterior Pituitary Cell Cultures from Two Primate Species. Sci Rep 2017; 7:43537. [PMID: 28349931 PMCID: PMC5640086 DOI: 10.1038/srep43537] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 01/25/2017] [Indexed: 12/27/2022] Open
Abstract
Adipose-tissue (AT) is an endocrine organ that dynamically secretes multiple hormones, the adipokines, which regulate key physiological processes. However, adipokines and their receptors are also expressed and regulated in other tissues, including the pituitary, suggesting that locally- and AT-produced adipokines might comprise a regulatory circuit that relevantly modulate pituitary cell-function. Here, we used primary pituitary cell-cultures from two normal nonhuman-primate species [Papio-anubis/Macaca-fascicularis] to determine the impact of different adipokines on the functioning of all anterior-pituitary cell-types. Leptin and resistin stimulated GH-release, a response that was blocked by somatostatin. Conversely, adiponectin decreased GH-release, and inhibited GHRH-, but not ghrelin-stimulated GH-secretion. Furthermore: 1) Leptin stimulated PRL/ACTH/FSH- but not LH/TSH-release; 2) adiponectin stimulated PRL-, inhibited ACTH- and did not alter LH/FSH/TSH-release; and 3) resistin increased ACTH-release and did not alter PRL/LH/FSH/TSH-secretion. These effects were mediated through the activation of common (AC/PKA) and distinct (PLC/PKC, intra-/extra-cellular calcium, PI3K/MAPK/mTOR) signaling-pathways, and by the gene-expression regulation of key receptors/transcriptional-factors involved in the functioning of these pituitary cell-types (e.g. GHRH/ghrelin/somatostatin/insulin/IGF-I-receptors/Pit-1). Finally, we found that primate pituitaries expressed leptin/adiponectin/resistin. Altogether, these and previous data suggest that local-production of adipokines/receptors, in conjunction with circulating adipokine-levels, might comprise a relevant regulatory circuit that contribute to the fine-regulation of pituitary functions.
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Affiliation(s)
- André Sarmento-Cabral
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Hospital Universitario Reina Sofía (HURS), Córdoba, Spain.,CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain.,Campus de Excelencia Internacional Agroalimentario (ceiA3), Córdoba, Spain
| | - Juan R Peinado
- Department of Medical Sciences, Faculty of Medicine of Ciudad Real, University of Castilla-La Mancha, Spain
| | - Lisa C Halliday
- Biologic Resources Laboratory, University of Illinois at Chicago, Chicago, Illinois, USA
| | - María M Malagon
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Hospital Universitario Reina Sofía (HURS), Córdoba, Spain.,CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
| | - Justo P Castaño
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Hospital Universitario Reina Sofía (HURS), Córdoba, Spain.,CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain.,Campus de Excelencia Internacional Agroalimentario (ceiA3), Córdoba, Spain
| | - Rhonda D Kineman
- Research and Development Division, Jesse Brown Veterans Affairs Medical Center, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Medicine, Section of Endocrinology, Diabetes, and Metabolism, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Raúl M Luque
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Hospital Universitario Reina Sofía (HURS), Córdoba, Spain.,CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain.,Campus de Excelencia Internacional Agroalimentario (ceiA3), Córdoba, Spain
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Odle AK, Allensworth-James ML, Akhter N, Syed M, Haney AC, MacNicol M, MacNicol AM, Childs GV. A Sex-Dependent, Tropic Role for Leptin in the Somatotrope as a Regulator of POU1F1 and POU1F1-Dependent Hormones. Endocrinology 2016; 157:3958-3971. [PMID: 27571135 PMCID: PMC5045503 DOI: 10.1210/en.2016-1472] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Pituitary somatotropes perform the key function of coordinating organismic growth and body composition with metabolic signals. However, the mechanism by which they sense and respond to metabolic signals via the adipokine leptin is unknown. The complex interplay between the heterogeneous cell types of the pituitary confounds the identification of somatotrope-specific mechanisms. Somatotropes represent 30%-40% of the anterior pituitary population and are derived from a lineage of cells that are activated by the Pit-Oct-Unc domain family domain class 1 transcription factor 1 (POU1F1) to produce GH, prolactin (PRL). and TSH. To determine the mechanism by which leptin controls somatotrope function, we used Cre-LoxP technology and fluorescence-activated cell sorting to purify and study control or leptin receptor-deleted (Lepr null) somatotropes. We report that Lepr-null somatotropes show significant reductions in GH protein (GH) and Gh mRNA. By contrast, enzyme immunoassays detected no changes in ACTH, LH, and FSH levels in mutants, indicating that the control of these hormones is independent of leptin signaling to somatotropes. Reduced TSH and PRL levels were also observed, but interestingly, this reduction occurred only in in Lepr-null somatotropes from mutant females and not from males. Consistent with the sex-specific reduction in Gh mRNA, TSH, and PRL, enzyme immunoassays detected a sex-specific reduction in POU1F1 protein levels in adult female Lepr-null somatotropes. Collectively, this study of purified Lepr-null somatotropes has uncovered an unexpected tropic role for leptin in the control of POU1F1 and all POU1F1-dependent hormones. This supports a broader role for somatotropes as metabolic sensors including sex-specific responses to leptin.
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Affiliation(s)
- Angela K Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Melody L Allensworth-James
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Noor Akhter
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Mohsin Syed
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Anessa C Haney
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Melanie MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Gwen V Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
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