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Sáenz de Miera C, Bellefontaine N, Allen SJ, Myers MG, Elias CF. Glutamate neurotransmission from leptin receptor cells is required for typical puberty and reproductive function in female mice. eLife 2024; 13:RP93204. [PMID: 39007235 PMCID: PMC11249761 DOI: 10.7554/elife.93204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024] Open
Abstract
The hypothalamic ventral premammillary nucleus (PMv) is a glutamatergic nucleus essential for the metabolic control of reproduction. However, conditional deletion of leptin receptor long form (LepRb) in vesicular glutamate transporter 2 (Vglut2) expressing neurons results in virtually no reproductive deficits. In this study, we determined the role of glutamatergic neurotransmission from leptin responsive PMv neurons on puberty and fertility. We first assessed if stimulation of PMv neurons induces luteinizing hormone (LH) release in fed adult females. We used the stimulatory form of designer receptor exclusively activated by designer drugs (DREADDs) in LeprCre (LepRb-Cre) mice. We collected blood sequentially before and for 1 hr after intravenous clozapine-N-oxide injection. LH level increased in animals correctly targeted to the PMv, and LH level was correlated to the number of Fos immunoreactive neurons in the PMv. Next, females with deletion of Slc17a6 (Vglut2) in LepRb neurons (LeprΔVGlut2) showed delayed age of puberty, disrupted estrous cycles, increased gonadotropin-releasing hormone (GnRH) concentration in the axon terminals, and disrupted LH secretion, suggesting impaired GnRH release. To assess if glutamate is required for PMv actions in pubertal development, we generated a Cre-induced reexpression of endogenous LepRb (LeprloxTB) with concomitant deletion of Slc17a6 (Vglut2flox) mice. Rescue of Lepr and deletion of Slc17a6 in the PMv was obtained by stereotaxic injection of an adeno-associated virus vector expressing Cre recombinase. Control LeprloxTB mice with PMv LepRb rescue showed vaginal opening, follicle maturation, and became pregnant, while LeprloxTB;Vglut2flox mice showed no pubertal development. Our results indicate that glutamatergic neurotransmission from leptin sensitive neurons regulates the reproductive axis, and that leptin action on pubertal development via PMv neurons requires Vglut2.
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Affiliation(s)
- Cristina Sáenz de Miera
- Department of Molecular and Integrative Physiology, University of Michigan–Ann ArborAnn ArborUnited States
| | - Nicole Bellefontaine
- Department of Molecular and Integrative Physiology, University of Michigan–Ann ArborAnn ArborUnited States
| | - Susan J Allen
- Department of Molecular and Integrative Physiology, University of Michigan–Ann ArborAnn ArborUnited States
| | - Martin G Myers
- Department of Molecular and Integrative Physiology, University of Michigan–Ann ArborAnn ArborUnited States
- Elizabeth W. Caswell Diabetes Institute, University of Michigan–Ann ArborAnn ArborUnited States
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan–Ann ArborAnn ArborUnited States
| | - Carol F Elias
- Department of Molecular and Integrative Physiology, University of Michigan–Ann ArborAnn ArborUnited States
- Elizabeth W. Caswell Diabetes Institute, University of Michigan–Ann ArborAnn ArborUnited States
- Department of Obstetrics and Gynecology, University of Michigan–Ann ArborAnn ArborUnited States
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de Miera CS, Bellefontaine N, Allen SJ, Myers MG, Elias CF. Glutamate neurotransmission from leptin receptor cells is required for typical puberty and reproductive function in female mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.21.558865. [PMID: 37790549 PMCID: PMC10542178 DOI: 10.1101/2023.09.21.558865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The hypothalamic ventral premammillary nucleus (PMv) is a glutamatergic nucleus essential for the metabolic control of reproduction. However, conditional deletion of leptin receptor (LepRb) in vesicular glutamate transporter 2 (Vglut2) expressing neurons results in virtually no reproductive deficits. In this study, we determine the role of glutamatergic signaling from leptin responsive PMv neurons on puberty and fertility. We first assessed if stimulation of PMv neurons induces LH release in fed adult females. We used the stimulatory form of designer receptor exclusively activated by designer drugs (DREADDs) in LepRb-Cre mice. We collected blood sequentially before and for 1h after iv. clozapine-N-oxide injection. LH level increased in animals correctly targeted to the PMv, and LH level was correlated to the number of cFos immunoreactive neurons in the PMv. Next, females with deletion of Vglut2 in LepRb neurons (LepR∆VGlut2) showed delayed age of puberty, disrupted estrous cycles, increased GnRH concentration in the axon terminals and disrupted LH responses, suggesting impaired GnRH release. To assess if glutamate is required for PMv actions in pubertal development, we generated a Cre-induced reexpression of endogenous LepRb (LepRloxTB) with concomitant deletion of Vglut2 (Vglut2-floxed) mice. Rescue of Lepr and deletion of Vglut2 in the PMv was obtained by stereotaxic injection of an adeno-associated virus vector expressing Cre recombinase. Control LepRloxTB mice with PMv LepRb rescue showed vaginal opening, follicle maturation and became pregnant, while LepRloxTB;Vglut2flox mice showed no pubertal development. Our results indicate that glutamatergic signaling from leptin sensitive neurons regulates the reproductive axis, and that leptin action on pubertal development via PMv neurons requires Vglut2.
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Affiliation(s)
- Cristina Sáenz de Miera
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109-5622, USA
| | - Nicole Bellefontaine
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109-5622, USA
| | - Susan J. Allen
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109-5622, USA
| | - Martin G. Myers
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109-5622, USA
- Elizabeth W. Caswell Diabetes Institute, University of Michigan, Ann Arbor, MI, 48109-5622, USA
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, 48109-5622, USA
| | - Carol F. Elias
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109-5622, USA
- Elizabeth W. Caswell Diabetes Institute, University of Michigan, Ann Arbor, MI, 48109-5622, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, 48109-5622, USA
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Athar F, Karmani M, Templeman N. Metabolic hormones are integral regulators of female reproductive health and function. Biosci Rep 2024; 44:BSR20231916. [PMID: 38131197 PMCID: PMC10830447 DOI: 10.1042/bsr20231916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 11/29/2023] [Accepted: 12/21/2023] [Indexed: 12/23/2023] Open
Abstract
The female reproductive system is strongly influenced by nutrition and energy balance. It is well known that food restriction or energy depletion can induce suppression of reproductive processes, while overnutrition is associated with reproductive dysfunction. However, the intricate mechanisms through which nutritional inputs and metabolic health are integrated into the coordination of reproduction are still being defined. In this review, we describe evidence for essential contributions by hormones that are responsive to food intake or fuel stores. Key metabolic hormones-including insulin, the incretins (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), growth hormone, ghrelin, leptin, and adiponectin-signal throughout the hypothalamic-pituitary-gonadal axis to support or suppress reproduction. We synthesize current knowledge on how these multifaceted hormones interact with the brain, pituitary, and ovaries to regulate functioning of the female reproductive system, incorporating in vitro and in vivo data from animal models and humans. Metabolic hormones are involved in orchestrating reproductive processes in healthy states, but some also play a significant role in the pathophysiology or treatment strategies of female reproductive disorders. Further understanding of the complex interrelationships between metabolic health and female reproductive function has important implications for improving women's health overall.
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Affiliation(s)
- Faria Athar
- Department of Biology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Muskan Karmani
- Department of Biology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Nicole M. Templeman
- Department of Biology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
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Nestor CC, Merkley CM, Lehman MN, Hileman SM, Goodman RL. KNDy neurons as the GnRH pulse generator: Recent studies in ruminants. Peptides 2023; 164:171005. [PMID: 36990389 PMCID: PMC10164117 DOI: 10.1016/j.peptides.2023.171005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/10/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023]
Abstract
This review considers three aspects of recent work on the role of KNDy neurons in GnRH pulse generation in ruminants. First, work on basic mechanisms of pulse generation includes several tests of this hypothesis, all of which support it, and evidence that Kiss1r-containing neurons form a positive feedback circuit with the KNDy neural network that strengthen the activity of this network. The second section on pathways mediating external inputs focuses on the influence of nutrition and photoperiod, and describes the evidence supporting roles for proopiomelanocortin (POMC) and agouti-related peptide (AgRP) afferents to KNDy cells in each of these. Finally, we review studies exploring the potential applications of manipulating signaling by kisspeptin, and the other KNDy peptides, to control reproductive function in domestic animals and conclude that, although these approaches show some promise, they do not have major advantages over current practices at this time.
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Affiliation(s)
- Casey C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, NC, USA
| | | | - Michael N Lehman
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Stanley M Hileman
- Department of Physiology, Pharmacology, and Toxicology, West Virginia University, Morgantown, WV, USA
| | - Robert L Goodman
- Department of Physiology, Pharmacology, and Toxicology, West Virginia University, Morgantown, WV, USA.
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Cara AL, Burger LL, Beekly BG, Allen SJ, Henson EL, Auchus RJ, Myers MG, Moenter SM, Elias CF. Deletion of Androgen Receptor in LepRb Cells Improves Estrous Cycles in Prenatally Androgenized Mice. Endocrinology 2023; 164:bqad015. [PMID: 36683455 PMCID: PMC10091504 DOI: 10.1210/endocr/bqad015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 01/13/2023] [Accepted: 01/18/2023] [Indexed: 01/24/2023]
Abstract
Androgens are steroid hormones crucial for sexual differentiation of the brain and reproductive function. In excess, however, androgens may decrease fertility as observed in polycystic ovary syndrome, a common endocrine disorder characterized by oligo/anovulation and/or polycystic ovaries. Hyperandrogenism may also disrupt energy homeostasis, inducing higher central adiposity, insulin resistance, and glucose intolerance, which may exacerbate reproductive dysfunction. Androgens bind to androgen receptors (ARs), which are expressed in many reproductive and metabolic tissues, including brain sites that regulate the hypothalamo-pituitary-gonadal axis and energy homeostasis. The neuronal populations affected by androgen excess, however, have not been defined. We and others have shown that, in mice, AR is highly expressed in leptin receptor (LepRb) neurons, particularly in the arcuate (ARH) and the ventral premammillary nuclei (PMv). Here, we assessed if LepRb neurons, which are critical in the central regulation of energy homeostasis and exert permissive actions on puberty and fertility, have a role in the pathogenesis of female hyperandrogenism. Prenatally androgenized (PNA) mice lacking AR in LepRb cells (LepRbΔAR) show no changes in body mass, body composition, glucose homeostasis, or sexual maturation. They do show, however, a remarkable improvement of estrous cycles combined with normalization of ovary morphology compared to PNA controls. Our findings indicate that the prenatal androgenization effects on adult reproductive physiology (ie, anestrus and anovulation) are mediated by a subpopulation of LepRb neurons directly sensitive to androgens. They also suggest that the effects of hyperandrogenism on sexual maturation and reproductive function in adult females are controlled by distinct neural circuits.
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Affiliation(s)
- Alexandra L Cara
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Laura L Burger
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Bethany G Beekly
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Susan J Allen
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Emily L Henson
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Richard J Auchus
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Martin G Myers
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Suzanne M Moenter
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Carol F Elias
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Guirado J, Carranza-Valencia J, Morante J. Mammalian puberty: a fly perspective. FEBS J 2023; 290:359-369. [PMID: 35607827 PMCID: PMC10084137 DOI: 10.1111/febs.16534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/02/2022] [Accepted: 05/23/2022] [Indexed: 02/05/2023]
Abstract
Mammalian puberty and Drosophila metamorphosis, despite their evolutionary distance, exhibit similar design principles and conservation of molecular components. In this Viewpoint, we review recent advances in this area and the similarities between both processes in terms of the signaling pathways and neuroendocrine circuits involved. We argue that the detection and uptake of peripheral fat by Drosophila prothoracic endocrine cells induces endomembrane remodeling and ribosomal maturation, leading to the acquisition of high biosynthetic and secretory capacity. The absence of this fat-neuroendocrine interorgan communication leads to giant, obese, non-pupating larvae. Importantly, human leptin is capable of signaling the pupariation process in Drosophila, and its expression prevents obesity and triggers maturation in mutants that do not pupate. This implies that insect metamorphosis can be used to address issues related to the biology of leptin and puberty.
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Affiliation(s)
- Juan Guirado
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), San Juan de Alicante, Spain
| | - Juan Carranza-Valencia
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), San Juan de Alicante, Spain
| | - Javier Morante
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), San Juan de Alicante, Spain
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Harlow K, Griesgraber MJ, Seman AD, Shuping SL, Sommer JR, Griffith EH, Hileman SM, Nestor CC. The impact of undernutrition on KNDy (kisspeptin/neurokinin B/dynorphin) neurons in female lambs. J Neuroendocrinol 2022; 34:e13135. [PMID: 35579068 PMCID: PMC9286635 DOI: 10.1111/jne.13135] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 03/25/2022] [Accepted: 03/27/2022] [Indexed: 11/30/2022]
Abstract
Undernutrition limits reproduction through inhibition of gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) secretion. Because KNDy neurons coexpress neuropeptides that play stimulatory (kisspeptin and neurokinin B [NKB]) and inhibitory (dynorphin) roles in pulsatile GnRH/LH release, we hypothesized that undernutrition would inhibit kisspeptin and NKB expression at the same time as increasing dynorphin expression. Fifteen ovariectomized lambs were either fed to maintain pre-study body weight (controls) or feed-restricted to lose 20% of pre-study body weight (FR) over 13 weeks. Blood samples were collected and plasma from weeks 0 and 13 were assessed for LH by radioimmunoassay. At week 13, animals were killed, and brain tissue was processed for assessment of KNDy peptide mRNA or protein expression. Mean LH and LH pulse amplitude were lower in FR lambs compared to controls. We observed lower mRNA abundance for kisspeptin within KNDy neurons of FR lambs compared to controls with no significant change in mRNA for NKB or dynorphin. We also observed that FR lambs had fewer numbers of arcuate nucleus kisspeptin and NKB perikarya compared to controls. These findings support the idea that KNDy neurons are important for regulating reproduction during undernutrition in female sheep.
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Affiliation(s)
- KaLynn Harlow
- Department of Animal ScienceNorth Carolina State UniversityRaleighNCUSA
| | - Max J. Griesgraber
- Department of Physiology and PharmacologyWest Virginia UniversityMorgantownWVUSA
| | - Andrew D. Seman
- Department of Physiology and PharmacologyWest Virginia UniversityMorgantownWVUSA
| | - Sydney L. Shuping
- Department of Animal ScienceNorth Carolina State UniversityRaleighNCUSA
| | - Jeffrey R. Sommer
- Department of Animal ScienceNorth Carolina State UniversityRaleighNCUSA
| | | | - Stanley M. Hileman
- Department of Physiology and PharmacologyWest Virginia UniversityMorgantownWVUSA
- Department of NeuroscienceWest Virginia UniversityMorgantownWVUSA
| | - Casey C Nestor
- Department of Animal ScienceNorth Carolina State UniversityRaleighNCUSA
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Wen Z, Qiaoqian Z, Wen S, Yonghong W, Jingwei H. Clinical changes of leptin/ghrelin and PAI-1 levels in adolescent girls with abnormal uterine bleeding-ovulatory dysfunction. Gynecol Endocrinol 2022; 38:345-349. [PMID: 35238278 DOI: 10.1080/09513590.2022.2045938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE To observe and compare the expression of energy regulators (leptin/ghrelin) and PAI-1 in girls with abnormal uterine bleeding-ovulatory dysfunction (AUB-O) and healthy adolescent girls. METHODS A total of 80 adolescent girls were studied including 60 with AUB-O and 20 healthy girls. All the general characteristics of subjects including height, weight, age, and age at menarche were collected after consent. The concentration of plasma leptin, ghrelin, PAI-1, and sex hormones was examined using enzyme-linked immunosorbent assay (ELISA) and DXI800 Access immunoassay system respectively. RESULTS Two groups were comparable in the age at menarche, visiting age, postmenarchal years, and BMI SDS (p > .05). Levels of leptin (11.12 ± 4.96 ng/ml vs. 18.59 ± 13.22 ng/ml, p < .001) and PAI-1 (116.40 ± 36.63 ng/ml vs. 173.19 ± 52.44 ng/ml, p < .001) in girls with AUB-O were significantly lower than that in healthy girls, and the levels of ghrelin were significantly higher than that in healthy girls (1.52 ± 4.20 ng/ml vs. 0.43 ± 0.64 ng/ml, p = .01). At the same time, we also found that girls with AUB-O showed negative correlation between the level of leptin, ghrelin, and estradiol. CONCLUSIONS Energy metabolism and coagulation might play a role in the development of AUB-O in adolescent girls.
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Affiliation(s)
- Zhao Wen
- National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, PR China
| | - Zeng Qiaoqian
- National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, PR China
| | - Sun Wen
- National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, PR China
| | - Wang Yonghong
- National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, PR China
| | - He Jingwei
- National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, PR China
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Rønnekleiv OK, Qiu J, Kelly MJ. Hypothalamic Kisspeptin Neurons and the Control of Homeostasis. Endocrinology 2022; 163:bqab253. [PMID: 34953135 PMCID: PMC8758343 DOI: 10.1210/endocr/bqab253] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Indexed: 12/27/2022]
Abstract
Hypothalamic kisspeptin (Kiss1) neurons provide indispensable excitatory transmission to gonadotropin-releasing hormone (GnRH) neurons for the coordinated release of gonadotropins, estrous cyclicity, and ovulation. But maintaining reproductive functions is metabolically demanding so there must be a coordination with multiple homeostatic functions, and it is apparent that Kiss1 neurons play that role. There are 2 distinct populations of hypothalamic Kiss1 neurons, namely arcuate nucleus (Kiss1ARH) neurons and anteroventral periventricular and periventricular nucleus (Kiss1AVPV/PeN) neurons in rodents, both of which excite GnRH neurons via kisspeptin release but are differentially regulated by ovarian steroids. Estradiol (E2) increases the expression of kisspeptin in Kiss1AVPV/PeN neurons but decreases its expression in Kiss1ARH neurons. Also, Kiss1ARH neurons coexpress glutamate and Kiss1AVPV/PeN neurons coexpress gamma aminobutyric acid (GABA), both of which are upregulated by E2 in females. Also, Kiss1ARH neurons express critical metabolic hormone receptors, and these neurons are excited by insulin and leptin during the fed state. Moreover, Kiss1ARH neurons project to and excite the anorexigenic proopiomelanocortin neurons but inhibit the orexigenic neuropeptide Y/Agouti-related peptide neurons, highlighting their role in regulating feeding behavior. Kiss1ARH and Kiss1AVPV/PeN neurons also project to the preautonomic paraventricular nucleus (satiety) neurons and the dorsomedial nucleus (energy expenditure) neurons to differentially regulate their function via glutamate and GABA release, respectively. Therefore, this review will address not only how Kiss1 neurons govern GnRH release, but how they control other homeostatic functions through their peptidergic, glutamatergic and GABAergic synaptic connections, providing further evidence that Kiss1 neurons are the key neurons coordinating energy states with reproduction.
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Affiliation(s)
- Oline K Rønnekleiv
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA
| | - Jian Qiu
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Martin J Kelly
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA
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Β-endorphin-immunoreactive perikarya appear to receive innervation from NPY-immunoreactive fiber varicosities in the human hypothalamus. Brain Struct Funct 2021; 227:821-828. [PMID: 34716471 DOI: 10.1007/s00429-021-02416-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 10/17/2021] [Indexed: 10/20/2022]
Abstract
Morphological and pharmacological studies indicate that hypothalamic neuropeptide Y (NPY) and proopiomelanocortin (POMC) neurons communicate with each other in rats and regulate a variety of hypothalamic and extrahypothalamic functions. Indeed, electron microscopic studies revealed NPY-immunoreactive (NPI-IR) synapses on β-endorphin-IR neurons in the hypothalamus. However, no such connections have been reported in humans. Here, we studied the putative NPY-β-endorphin associations with high-resolution light microscopic double-label immunocytochemistry in the human hypothalamus. The majority of β-endorphin-IR perikarya appear to be innervated by abutting NPY-IR fibers in the infundibulum/median eminence, receiving more than 6 contacts (38% of the counted neurons) or three to six contacts (42% of the counted neurons). The rest of the β-endorphin-IR neurons are lightly innervated by NPY fibers (14%, one-three contacts) or do not receive any detectable NPY-IR axon varicosities (6% of the counted neurons). Since β-endorphin is cleaved from the proopiomelanocortin (POMC) precursor, the NPY-β-endorphin connections also provide the foundation for NPY-α-MSH and NPY-ACTH connections and their subsequent physiology. The close anatomical connections between NPY-IR nerve terminals and β-endorphin-IR neurons reported herein may represent functional synapses and provide the foundation for NPY-stimulated β-endorphin release. By interacting with β-endorphin, NPY may have a more widespread regulatory capacity than acting alone on different neurotransmitter systems.
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11
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Early Postnatal Genistein Administration Affects Mice Metabolism and Reproduction in a Sexually Dimorphic Way. Metabolites 2021; 11:metabo11070449. [PMID: 34357343 PMCID: PMC8303179 DOI: 10.3390/metabo11070449] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/04/2021] [Accepted: 07/07/2021] [Indexed: 12/30/2022] Open
Abstract
The phytoestrogen genistein (GEN) may interfere with permanent morphological changes in the brain circuits sensitive to estrogen. Due to the frequent use of soy milk in the neonatal diet, we aimed to study the effects of early GEN exposure on some physiological and reproductive parameters. Mice of both sexes from PND1 to PND8 were treated with GEN (50 mg/kg body weight, comparable to the exposure level in babies fed with soy-based formulas). When adult, we observed, in GEN-treated females, an advanced pubertal onset and an altered estrous cycle, and, in males, a decrease of testicle weight and fecal testosterone concentration. Furthermore, we observed an increase in body weight and altered plasma concentrations of metabolic hormones (leptin, ghrelin, triiodothyronine) limited to adult females. Exposure to GEN significantly altered kisspeptin and POMC immunoreactivity only in females and orexin immunoreactivity in both sexes. In conclusion, early postnatal exposure of mice to GEN determines long-term sex-specific organizational effects. It impairs the reproductive system and has an obesogenic effect only in females, which is probably due to the alterations of neuroendocrine circuits controlling metabolism; thus GEN, should be classified as a metabolism disrupting chemical.
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Yu Z, Zhan Q, Chen A, Han J, Zheng Y, Gong Y, Lu R, Zheng Z, Chen G. Intermittent fasting ameliorates di-(2-ethylhexyl) phthalate-induced precocious puberty in female rats: A study of the hypothalamic-pituitary-gonadal axis. Reprod Biol 2021; 21:100513. [PMID: 34049116 DOI: 10.1016/j.repbio.2021.100513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/29/2021] [Accepted: 05/11/2021] [Indexed: 11/18/2022]
Abstract
Di-(2-ethylhexyl) phthalate has been reported to interfere with the development and function of animal reproductive systems. However, hardly any studies provide methods to minimize or prevent the adverse effects of DEHP on reproduction. The energy balance state of mammals is closely related to reproductive activities, and the reproductive axis can regulate reproductive activities according to changes in the body's energy balance state. In this study, the effects of every other day fasting (EODF), as a way of intermittent fasting, on preventing the precocious puberty induced by DEHP in female rats was studied. EODF significantly improved the advancement of vaginal opening age (as the markers of puberty onset) and elevated serum levels of luteinizing hormone and estradiol (detected by ELISA) induced by 5 mg kg-1 DEHP exposure (D5). The mRNA and western blot results showed that the EODF could minimized the increase of gonadotropin-releasing hormone expression induced by DEHP exposure. The administration of DEHP could elevate the levels of kisspeptin protein and the number of kisspeptin-immunoreactive neurons in anteroventral periventricular nucleu, and this increase was diminished considerably by EODF treatment. In contrast, the D5 and D0 groups showed no remarkable difference in the level of Kiss1 expression in arcuate nucleus, whereas the D5 + EODF group had a remarkable decrease in kisspeptin expression as compared with the other two groups. Our results indicated that EODF might inhibit the acceleration of puberty onset induced by DEHP exposure via HPG axis.
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Affiliation(s)
- Zhen Yu
- Fujian Provincial Key Laboratory of Medical Analysis, Fujian Academy of Medical Sciences, Fuzhou, 350001, China
| | - Qiufeng Zhan
- Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China
| | - Ayun Chen
- Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China
| | - Junyong Han
- Fujian Provincial Key Laboratory of Medical Analysis, Fujian Academy of Medical Sciences, Fuzhou, 350001, China
| | - Yuanyuan Zheng
- Fujian Provincial Key Laboratory of Medical Analysis, Fujian Academy of Medical Sciences, Fuzhou, 350001, China; Department of Endocrinology, Fujian Provincial Hospital, Fuzhou, 350001, China
| | - Yuqing Gong
- Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China
| | - Rongmei Lu
- Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China; Department of Endocrinology, Fujian Provincial Hospital, Fuzhou, 350001, China
| | - Zeyu Zheng
- Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China
| | - Gang Chen
- Fujian Provincial Key Laboratory of Medical Analysis, Fujian Academy of Medical Sciences, Fuzhou, 350001, China; Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China; Department of Endocrinology, Fujian Provincial Hospital, Fuzhou, 350001, China.
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13
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Merkley CM, Shuping SL, Sommer JR, Nestor CC. Evidence That Agouti-Related Peptide May Directly Regulate Kisspeptin Neurons in Male Sheep. Metabolites 2021; 11:138. [PMID: 33652696 PMCID: PMC7996775 DOI: 10.3390/metabo11030138] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 12/21/2022] Open
Abstract
Agouti-related peptide (AgRP) neurons, which relay information from peripheral metabolic signals, may constitute a key central regulator of reproduction. Given that AgRP inhibits luteinizing hormone (LH) secretion and that nutritional suppression of LH elicits an increase in AgRP while suppressing kisspeptin expression in the arcuate nucleus (ARC) of the hypothalamus, we sought to examine the degree to which AgRP could directly regulate ARC kisspeptin neurons. Hypothalamic tissue was collected from four castrated male sheep (10 months of age) and processed for the detection of protein (AgRP input to kisspeptin neurons) using immunohistochemistry and mRNA for melanocortin 3 and 4 receptors (MC3R; MC4R) in kisspeptin neurons using RNAscope. Immunohistochemical analysis revealed that the majority of ARC kisspeptin neurons are contacted by presumptive AgRP terminals. RNAscope analysis revealed that nearly two thirds of the ARC kisspeptin neurons express mRNA for MC3R, while a small percentage (<10%) colocalize MC4R. Taken together, this data provides neuroanatomical evidence for a direct link between orexigenic AgRP neurons and reproductively critical kisspeptin neurons in the sheep, and builds upon our current understanding of the central link between energy balance and reproduction.
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Affiliation(s)
| | | | | | - Casey C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA; (C.M.M.); (S.L.S.); (J.R.S.)
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14
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Anjum S, Khattak MNK, Tsutsui K, Krishna A. RF-amide related peptide-3 (RFRP-3): a novel neuroendocrine regulator of energy homeostasis, metabolism, and reproduction. Mol Biol Rep 2021; 48:1837-1852. [PMID: 33566226 DOI: 10.1007/s11033-021-06198-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 01/28/2021] [Indexed: 11/29/2022]
Abstract
A hypothalamic neuropeptide, RF-amide related peptide-3 (RFRP-3), the mammalian ortholog of the avian gonadotropin-inhibitory hormone (GnIH) has inhibitory signals for reproductive axis via G-protein coupled receptor 147 in mammals. Moreover, RFRP-3 has orexigenic action but the mechanism involved in energy homeostasis and glucose metabolism is not yet known. Though, the RFRP-3 modulates orexigenic action in co-operation with other neuropeptides, which regulates metabolic cues in the hypothalamus. Administration of GnIH/RFRP-3 suppresses plasma luteinizing hormone, at the same time stimulates feeding behavior in birds and mammals. Likewise, in the metabolically deficient conditions, its expression is up-regulated suggests that RFRP-3 contributes to the integration of energy balance and reproduction. However, in many other metabolic conditions like induced diabetes and high-fat diet obesity, etc. its role is still not clear while, RFRP-3 induces the glucose homeostasis by adipocytes is reported. The physiological role of RFRP-3 in metabolic homeostasis and the metabolic effects of RFRP-3 signaling in pharmacological studies need a detailed discussion. Further studies are required to find out whether RFRP-3 is associated with restricted neuroendocrine function observed in type II diabetes mellitus, aging, or sub-fertility. In this context, the current review is focused on the role of RFRP-3 in the above-mentioned mechanisms. Studies from search engines including PubMed, Google Scholar, and science.gov are included after following set inclusion/exclusion criteria. As a developing field few mechanisms are still inconclusive, however, based on the available information RFRP-3 seems to be a putative tool in future treatment strategies towards metabolic disease.
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Affiliation(s)
- Shabana Anjum
- Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
- Sharjah Institute of Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | | | - Kazuyoshi Tsutsui
- Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama 1-7-1, Higashi-Hiroshima, 739-8521, Japan
| | - Amitabh Krishna
- Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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15
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Tzoupis H, Nteli A, Androutsou ME, Tselios T. Gonadotropin-Releasing Hormone and GnRH Receptor: Structure, Function and Drug Development. Curr Med Chem 2021; 27:6136-6158. [PMID: 31309882 DOI: 10.2174/0929867326666190712165444] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 01/11/2023]
Abstract
BACKGROUND Gonadotropin-Releasing Hormone (GnRH) is a key element in sexual maturation and regulation of the reproductive cycle in the human organism. GnRH interacts with the pituitary cells through the activation of the Gonadotropin Releasing Hormone Receptors (GnRHR). Any impairments/dysfunctions of the GnRH-GnRHR complex lead to the development of various cancer types and disorders. Furthermore, the identification of GnRHR as a potential drug target has led to the development of agonist and antagonist molecules implemented in various treatment protocols. The development of these drugs was based on the information derived from the functional studies of GnRH and GnRHR. OBJECTIVE This review aims at shedding light on the versatile function of GnRH and GnRH receptor and offers an apprehensive summary regarding the development of different agonists, antagonists and non-peptide GnRH analogues. CONCLUSION The information derived from these studies can enhance our understanding of the GnRH-GnRHR versatile nature and offer valuable insight into the design of new more potent molecules.
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Affiliation(s)
| | - Agathi Nteli
- Department of Chemistry, University of Patras, Rion GR-26504, Greece
| | - Maria-Eleni Androutsou
- Vianex S.A., Tatoiou Str., 18th km Athens-Lamia National Road, Nea Erythrea 14671, Greece
| | - Theodore Tselios
- Department of Chemistry, University of Patras, Rion GR-26504, Greece
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16
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D’Occhio MJ, Campanile G, Baruselli PS. Peripheral action of kisspeptin at reproductive tissues-role in ovarian function and embryo implantation and relevance to assisted reproductive technology in livestock: a review. Biol Reprod 2020; 103:1157-1170. [PMID: 32776148 PMCID: PMC7711897 DOI: 10.1093/biolre/ioaa135] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/23/2020] [Accepted: 08/07/2020] [Indexed: 12/13/2022] Open
Abstract
Kisspeptin (KISS1) is encoded by the KISS1 gene and was initially found to be a repressor of metastasis. Natural mutations in the KISS1 receptor gene (KISS1R) were subsequently shown to be associated with idiopathic hypothalamic hypogonadism and impaired puberty. This led to interest in the role of KISS1 in reproduction. It was established that KISS1 had a fundamental role in the control of gonadotropin releasing hormone (GnRH) secretion. KISS1 neurons have receptors for leptin and estrogen receptor α (ERα), which places KISS1 at the gateway of metabolic (leptin) and gonadal (ERα) regulation of GnRH secretion. More recently, KISS1 has been shown to act at peripheral reproductive tissues. KISS1 and KISS1R genes are expressed in follicles (granulosa, theca, oocyte), trophoblast, and uterus. KISS1 and KISS1R proteins are found in the same tissues. KISS1 appears to have autocrine and paracrine actions in follicle and oocyte maturation, trophoblast development, and implantation and placentation. In some studies, KISS1 was beneficial to in vitro oocyte maturation and blastocyst development. The next phase of KISS1 research will explore potential benefits on embryo survival and pregnancy. This will likely involve longer-term KISS1 treatments during proestrus, early embryo development, trophoblast attachment, and implantation and pregnancy. A deeper understanding of the direct action of KISS1 at reproductive tissues could help to achieve the next step change in embryo survival and improvement in the efficiency of assisted reproductive technology.
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Affiliation(s)
- Michael J D’Occhio
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, NSW, Australia
| | - Giuseppe Campanile
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Pietro S Baruselli
- Department of Animal Reproduction, Faculty of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, Brazil
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17
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Oliveira LLB, Del Bianco-Borges B, Franci CR. Estradiol and the feeding state modulate the interaction between leptin and the nitrergic system in female rats. Neuropeptides 2020; 84:102096. [PMID: 33059245 DOI: 10.1016/j.npep.2020.102096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 09/16/2020] [Accepted: 09/16/2020] [Indexed: 11/20/2022]
Abstract
Leptin mediates the interaction between reproductive function and energy balance. However, leptin receptors are not expressed in neurons that produce gonadotropin-releasing hormone (GnRH), likely indicating an indirect action through interneurons. Among likely neurons that modulate the secretion of GnRH are NO (nitric oxide) neurons. We assessed whether estradiol and feeding conditions modulate a possible interaction between leptin and NO in brain areas related to the control of reproductive function. Estradiol-treated and untreated ovariectomized rats were normally fed or fasted for 48 h. Then, saline (control) or leptin (3 μg/1 μl) intracerebroventricular microinjections were administered, and after thirty minutes, the brains collected subsequent to the decapitation or transcardially perfusion. Leptin and estradiol increased NO synthase (nNOS) gene expression (RT-PCR) and content (Western blotting) in the medial preoptic area (MPOA) and medial basal hypothalamus (MBH) only in fasted rats. Leptin increased: 1-phosphorylated-signal transducer and activator of transcription-3(pSTAT3) (immunohistochemistry) in the MPOA and various hypothalamic nuclei [arcuate (ARC); ventromedial (VMH); dorsal/ventral dorsomedial (dDMH/vDMH); premammilar ventral (PMV)], effects potentiated by estradiol/fasting interaction; 2- nNOS/pSTAT3 coexpression in the MPOA only in estradiol-treated, fasted rats; 3- nNOS-immunoreactive cell expression in the VMH, DMH and PMV (areas related to reproductive function control) of estradiol -treated rats. Thus, when leptin is reduced during fasting, leptin replacement effectively increased the expression of nitric oxide, which activated the HPG axis only in the presence of estradiol. Estradiol modulates the nitrergic system, leptin sensitivity and consequently leptin's effects on the nitrergic system in hypothalamus and in particular vDMH and PMV.
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Affiliation(s)
- L L B Oliveira
- Ribeirão Preto Medical School, Department of Physiology, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | | | - C R Franci
- Ribeirão Preto Medical School, Department of Physiology, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil.
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18
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Merkley CM, Renwick AN, Shuping SL, Harlow K, Sommer JR, Nestor CC. Undernutrition reduces kisspeptin and neurokinin B expression in castrated male sheep. REPRODUCTION AND FERTILITY 2020; 1:1-13. [PMID: 35128420 PMCID: PMC8812452 DOI: 10.1530/raf-20-0025] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 10/01/2020] [Indexed: 11/09/2022] Open
Abstract
Undernutrition impairs reproductive success through suppression of gonadotropin-releasing hormone (GnRH), and subsequently luteinizing hormone (LH), secretion. Given that kisspeptin and neurokinin B (NKB) neurons in the arcuate nucleus (ARC) of the hypothalamus are thought to play key stimulatory roles in the generation of GnRH/LH pulses, we hypothesized that feed restriction would reduce the ARC mRNA abundance and protein expression of kisspeptin and NKB in young, male sheep. Fourteen wethers (castrated male sheep five months of age) were either fed to maintain (FM; n = 6) pre-study body weight or feed-restricted (FR; n = 8) to lose 20% of pre-study body weight over 13 weeks. Throughout the study, weekly blood samples were collected and assessed for LH concentration using RIA. At Week 13 of the experiment, animals were killed, heads were perfused with 4% paraformaldehyde, and brain tissue containing the hypothalamus was collected, sectioned, and processed for detection of mRNA (RNAscope) and protein (immunohistochemistry) for kisspeptin and NKB. Mean LH was significantly lower and LH inter-pulse interval was significantly higher in FR wethers compared to FM wethers at the end of the experiment (Week 13). RNAscope analysis revealed significantly fewer cells expressing mRNA for kisspeptin and NKB in FR wethers compared to FM controls, and immunohistochemical analysis revealed significantly fewer immunopositive kisspeptin and NKB cells in FR wethers compared to FM wethers. Taken together, this data supports the idea that long-term feed restriction regulates GnRH/LH secretion through central suppression of kisspeptin and NKB in male sheep.
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Affiliation(s)
- Christina M Merkley
- Department of Animal Science, North Carolina State University, Raleigh, North Carolina, USA
| | - Allison N Renwick
- Department of Animal Science, North Carolina State University, Raleigh, North Carolina, USA
| | - Sydney L Shuping
- Department of Animal Science, North Carolina State University, Raleigh, North Carolina, USA
| | - KaLynn Harlow
- Department of Animal Science, North Carolina State University, Raleigh, North Carolina, USA
| | - Jeffrey R Sommer
- Department of Animal Science, North Carolina State University, Raleigh, North Carolina, USA
| | - Casey C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, North Carolina, USA
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19
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Patel R, Smith JT. Novel actions of kisspeptin signaling outside of GnRH-mediated fertility: a potential role in energy balance. Domest Anim Endocrinol 2020; 73:106467. [PMID: 32278499 DOI: 10.1016/j.domaniend.2020.106467] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 01/08/2023]
Abstract
Kisspeptin, encoded by Kiss1 gene expressing neurons in the hypothalamus, is a requisite for fertility and now appears critical in the regulation of energy balance. Kisspeptin neurons, particularly those in the arcuate nucleus (ARC), receive information directly and indirectly from a diverse array of brain regions including the bed nucleus of the stria terminalis, amygdala, interpeduncular nucleus, hippocampus, and cortex. On the other hand, kisspeptin neuron projections clearly extend to GnRH neuron cell bodies in rodents, sheep, and primates and beyond to other-non-GnRH-brain areas. Kiss1r, the kisspeptin receptor, is expressed on GnRH neurons and also in additional brain areas and peripheral tissues, indicating a nonreproductive role. Kisspeptin neurons clearly receive signals pertinent to deviations in energy balance but are now recognized as a novel neuroendocrine player in the fine balance of energy intake and expenditure. Mice that have a dysfunctional gene for Kiss1r develop an obese and diabetic phenotype. The mechanism behind this altered metabolic state is still mostly unknown; however, Kiss1r expression in the pancreas and brown adipose tissue is clearly functional and required for normal glucose tolerance and energy expenditure, respectively. Kisspeptin neurons in the ARC also participate in the generation of circadian rhythms, specifically those concerning food intake and metabolism, offering a potential explanation for the obesity in Kiss1r knockout mice. Overall, the discoveries of new mechanistic roles for kisspeptin in both normal and pathophysiologic states of energy balance may lead to further understating of obesity prevalence and novel therapeutic targets and interventions.
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Affiliation(s)
- R Patel
- School of Human Sciences, M309, The University of Western Australia, 35 Stirling Highway Crawley, Perth, Western Australia, Australia 6009
| | - J T Smith
- School of Human Sciences, M309, The University of Western Australia, 35 Stirling Highway Crawley, Perth, Western Australia, Australia 6009.
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20
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Lents CA, Lindo AN, Hileman SM, Nonneman DJ. Physiological and genomic insight into neuroendocrine regulation of puberty in gilts. Domest Anim Endocrinol 2020; 73:106446. [PMID: 32199704 DOI: 10.1016/j.domaniend.2020.106446] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 12/20/2022]
Abstract
The timing of pubertal attainment in gilts is a critical factor for pork production and is an early indicator of future reproductive potential. Puberty, defined as age at first standing estrus in the presence of a boar, is brought about by an escape from estrogen inhibition of the GnRH pulse generator, which allows for increasing LH pulses leading to the onset of cyclicity. The biological mechanisms that control the timing of these events is related to decreasing inhibitory signals with a concomitant increase in stimulatory signals within the hypothalamus. The roles of gamma-aminobutyric acid, endogenous opioid peptides, and gonadotropin-inhibitory hormone in negatively regulating gonadotropin secretion in gilts is explored. Developmental changes in stimulatory mechanisms of glutamatergic and kisspeptin neurons are important for increased LH pulsatility required for the occurrence of puberty in pigs. Age at first estrus of gilts is metabolically gated, and numerous metabolites, metabolic hormones, and appetite-regulating neurotransmitters have been implicated in the nutritional regulation of gonadotropin secretion. Leptin is an important metabolic signal linking body energy reserves with age at puberty in gilts. Leptin acting through neuropeptide Y and proopiomelanocortin neurons in the hypothalamus has important impacts on the function of the reproductive neurosecretory axis of gilts. Age at puberty in swine is heritable, and genomic analyses reveal it to be a polygenic trait. Genome-wide association studies for pubertal age in gilts have revealed several genomic regions in common with those identified for age at menarche in humans. Candidate genes have been identified that have important functions in growth and adiposity. Numerous genes regulating hypothalamic neuronal function, gonadotropes in the adenohypophysis, and ovarian follicular development have been identified and illustrate the complex maturational changes occurring in the hypothalamic-pituitary-ovarian axis during puberty in gilts.
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Affiliation(s)
- C A Lents
- USDA, ARS, U.S. Meat Animal Research Center, Reproduction Research Unit, Clay Center, NE 68966-0166, USA.
| | - A N Lindo
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV 26506-9600, USA
| | - S M Hileman
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV 26506-9600, USA
| | - D J Nonneman
- USDA, ARS, U.S. Meat Animal Research Center, Reproduction Research Unit, Clay Center, NE 68966-0166, USA
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21
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Merkley CM, Shuping SL, Nestor CC. Neuronal networks that regulate gonadotropin-releasing hormone/luteinizing hormone secretion during undernutrition: evidence from sheep. Domest Anim Endocrinol 2020; 73:106469. [PMID: 32247618 DOI: 10.1016/j.domaniend.2020.106469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/26/2020] [Accepted: 02/28/2020] [Indexed: 01/19/2023]
Abstract
Gonadotropin-releasing hormone (GnRH) neurons are the final common conduit from the central nervous system in the reproductive axis, controlling luteinizing hormone (LH) secretion from the gonadotropes of the anterior pituitary. Although it is generally accepted that undernutrition inhibits GnRH/LH secretion, the central mechanisms that underlie the link between energy balance and reproduction remain to be fully elucidated. Sheep have been a longstanding and invaluable animal model for examination of the nutritional regulation of GnRH/LH secretion, given their ability to serve a biomedical and agricultural purpose. In this review, we summarize work that has used the ovine model to examine the central mechanisms whereby undernutrition regulates GnRH/LH secretion. Specifically, we focus our attention to the arcuate nucleus of the hypothalamus and on neurons that express kisspeptin, neurokinin B, dynorphin, proopiomelanocortin, and neuropeptide y/agouti-related peptide (NPY/AgRP). We examine their roles in mediating the effects of leptin and insulin and their effects on LH during undernutrition, as well as their regulation under conditions of undernutrition. This review will also highlight the interactions between the aforementioned neuronal networks themselves, which may be important for our understanding of the roles each play in relaying information regarding energy status during times of undernutrition to ultimately regulate GnRH/LH secretion.
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Affiliation(s)
- C M Merkley
- Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA
| | - S L Shuping
- Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA
| | - C C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA.
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22
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Rietema SE, Hawken PAR, Scott CJ, Lehman MN, Martin GB, Smith JT. Arcuate nucleus kisspeptin response to increased nutrition in rams. Reprod Fertil Dev 2020; 31:1682-1691. [PMID: 31511141 DOI: 10.1071/rd19063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 06/16/2019] [Indexed: 11/23/2022] Open
Abstract
Rams respond to acute nutritional supplementation by increasing the frequency of gonadotrophin-releasing hormone (GnRH) pulses. Kisspeptin neurons may mediate the effect of environmental cues on GnRH secretion, so we tested whether the ram response to nutrition involves activation of kisspeptin neurons in the arcuate nucleus (ARC), namely kisspeptin, neurokin B, dynorphin (KNDy) neurons. Rams were given extra lupin grain with their normal ration. Blood was sampled before feeding, and continued until animals were killed for collection of brain tissue at 2 or 11h after supplementation. In supplemented rams, LH pulse frequency increased after feeding, whereas control animals showed no change. Within the caudal ARC, there were more kisspeptin neurons in supplemented rams than in controls and a higher proportion of kisspeptin cells coexpressed Fos, regardless of the time the rams were killed. There were more Fos cells in the mid-ARC and mid-dorsomedial hypothalamus of the supplemented compared with control rams. No effect of nutrition was found on kisspeptin expression in the rostral or mid-ARC, or on GnRH expression in the preoptic area. Kisspeptin neurons in the caudal ARC appear to mediate the increase in GnRH and LH production due to acute nutritional supplementation, supporting the hypothesised role of the KNDy neurons as the pulse generator for GnRH.
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Affiliation(s)
- S E Rietema
- School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - P A R Hawken
- School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - C J Scott
- School of Biomedical Sciences, Charles Sturt University, Boorooma Street, Wagga Wagga, NSW 2678, Australia
| | - M N Lehman
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, PO Box 5190, Kent, OH 44242-0001, USA
| | - G B Martin
- School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - J T Smith
- The School of Human Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia; and Corresponding author.
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23
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Cara AL, Myers MG, Elias CF. Lack of AR in LepRb Cells Disrupts Ambulatory Activity and Neuroendocrine Axes in a Sex-Specific Manner in Mice. Endocrinology 2020; 161:bqaa110. [PMID: 32609838 PMCID: PMC7383963 DOI: 10.1210/endocr/bqaa110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/26/2020] [Indexed: 11/19/2022]
Abstract
Disorders of androgen imbalance, such as hyperandrogenism in females or hypoandrogenism in males, increase risk of visceral adiposity, type 2 diabetes, and infertility. Androgens act upon androgen receptors (AR) which are expressed in many tissues. In the brain, AR are abundant in hypothalamic nuclei involved in regulation of reproduction and energy homeostasis, yet the role of androgens acting via AR in specific neuronal populations has not been fully elucidated. Leptin receptor (LepRb)-expressing neurons coexpress AR predominantly in hypothalamic arcuate and ventral premammillary nuclei (ARH and PMv, respectively), with low colocalization in other LepRb neuronal populations, and very low colocalization in the pituitary gland and gonads. Deletion of AR from LepRb-expressing cells (LepRbΔAR) has no effect on body weight, energy expenditure, and glucose homeostasis in male and female mice. However, LepRbΔAR female mice show increased body length later in life, whereas male LepRbΔAR mice show an increase in spontaneous ambulatory activity. LepRbΔAR mice display typical pubertal timing, estrous cycles, and fertility, but increased testosterone levels in males. Removal of sex steroid negative feedback action induced an exaggerated rise in luteinizing hormone in LepRbΔAR males and follicle-stimulating hormone in LepRbΔAR females. Our findings show that AR can directly affect a subset of ARH and PMv neurons in a sex-specific manner and demonstrate specific androgenic actions in the neuroendocrine hypothalamus.
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Affiliation(s)
- Alexandra L Cara
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Martin G Myers
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Carol F Elias
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
- Department of Obstetrics and Gynaecology, University of Michigan, Ann Arbor, Michigan
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Pool KR, Rickard JP, de Graaf SP. Overcoming neuroendocrine and metabolic barriers to puberty: the role of melatonin in advancing puberty in ewe lambs. Domest Anim Endocrinol 2020; 72:106457. [PMID: 32361422 DOI: 10.1016/j.domaniend.2020.106457] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 01/07/2020] [Accepted: 02/19/2020] [Indexed: 02/05/2023]
Abstract
Pubertal onset in the ewe is subject to a multitude of physiological and environmental constraints. As seasonal breeders, sheep rely on decreasing photoperiod to enter puberty and the subsequent breeding periods, hindering production. The initiation of puberty defines the reproductive yield of the ewe, and as such is a critical factor influencing production outcomes. Currently, the misconception that ovine puberty is reliant on age results in ewes being bred at over a year old, leading to a substantial unproductive period between birth and first conception. As such, transcending pubertal barriers to allow for earlier initiation of reproductive competency has significant commercial merit. The primary candidate to achieve this is the neurohormone melatonin, a key factor that naturally signals photoperiodic change that facilitates seasonal remodeling of the ovine hypothalamic-hypophyseal-gonadal axis. Despite being known to modulate reproductive seasonality in both the mature ewe and ram, the ability of melatonin to advance ewe puberty remains underutilized in industry. To optimize melatonin application and shape perceptions of breeding ewe lambs, a greater understanding of pubertal impediments and the natural role of melatonin is warranted. This review examines the physiological role and applications of melatonin to advance ewe puberty, and how this may act in conjunction with other physiological and metabolic cues.
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Affiliation(s)
- K R Pool
- The University of Sydney, Faculty of Science, School of Life and Environmental Sciences, Sydney, NSW 2006, Australia.
| | - J P Rickard
- The University of Sydney, Faculty of Science, School of Life and Environmental Sciences, Sydney, NSW 2006, Australia
| | - S P de Graaf
- The University of Sydney, Faculty of Science, School of Life and Environmental Sciences, Sydney, NSW 2006, Australia
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25
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Malik IA, Durairajanayagam D, Singh HJ. Leptin and its actions on reproduction in males. Asian J Androl 2020; 21:296-299. [PMID: 30539926 PMCID: PMC6498734 DOI: 10.4103/aja.aja_98_18] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Leptin, an adipocyte-derived hormone, serves numerous physiological functions in the body, particularly during puberty and reproduction. The exact mechanism by which leptin activates the gonadotropin-releasing hormone (GnRH) neurons to trigger puberty and reproduction remains unclear. Given the widespread distribution of leptin receptors in the body, both central and peripheral mechanisms involving the hypothalamic-pituitary-gonadal axis have been hypothesized. Leptin is necessary for normal reproductive function, but when present in excess, it can have detrimental effects on the male reproductive system. Human and animal studies point to leptin as a link between infertility and obesity, a suggestion that is corroborated by findings of low sperm count, increased sperm abnormalities, oxidative stress, and increased leptin levels in obese men. In addition, daily leptin administration to normal-weight rats has been shown to result in similar abnormalities in sperm parameters. The major pathways causing these abnormalities remain unidentified; however, these adverse effects have been attributed to leptin-induced increased oxidative stress because they are prevented by concurrently administering melatonin. Studies on leptin and its impact on sperm function are highly relevant in understanding and managing male infertility, particularly in overweight and obese men.
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Affiliation(s)
- Ifrah Alam Malik
- Department of Physiology, Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh Campus, Sg Buloh 47000, Selangor, Malaysia
| | - Damayanthi Durairajanayagam
- Department of Physiology, Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh Campus, Sg Buloh 47000, Selangor, Malaysia
| | - Harbindar Jeet Singh
- Department of Physiology, Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh Campus, Sg Buloh 47000, Selangor, Malaysia.,2I-PPerForM, Universiti Teknologi MARA, Sungai Buloh Campus, Sg Buloh 47000, Selangor, Malaysia
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26
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Rønnekleiv OK, Qiu J, Kelly MJ. Arcuate Kisspeptin Neurons Coordinate Reproductive Activities with Metabolism. Semin Reprod Med 2019; 37:131-140. [PMID: 31869841 DOI: 10.1055/s-0039-3400251] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Hypothalamic control of fertility is the quintessential homeostatic function. However, fertility is metabolically demanding; so, there must be coordination between energy states and reproductive functions. Because gonadotropin-releasing hormone (GnRH) neurons are devoid of many of the critical metabolic hormone receptors for sensing nutrient levels, it has long been recognized that the sensing of energy stores had to be done by neurons presynaptic to GnRH neurons. Some of the obvious players have been the anorexigenic proopiomelanocortin (POMC) and orexigenic neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons, both of which are in close apposition to the median eminence, a circumventricular organ. Indeed, POMC and NPY/AgRP neurons are inversely regulated by glucose and metabolic hormones including insulin and leptin. However, their synaptic connections with GnRH neurons are sparse and/or GnRH neurons are lacking the postsynaptic receptors to mediate the appropriate physiological response. Kisspeptin neurons were discovered in the early part of this century and subsequently shown to project to and control GnRH neuronal excitability. In fact, more recently the arcuate kisspeptin neurons have been identified as the command neurons driving pulsatile release of GnRH. Subsequently, it was shown that arcuate kisspeptin neurons express not only steroid hormone receptors but also metabolic hormone receptors such that similar to POMC neurons, they are excited by insulin and leptin. Therefore, based on the premise that arcuate kisspeptin neurons are the key neurons coordinating energy states with reproduction, we will review not only how these vital neurons control pulsatile GnRH release but how they control energy homeostasis through their synaptic connections with POMC and NPY/AgRP neurons and ultimately how E2 can regulate their excitability.
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Affiliation(s)
- Oline K Rønnekleiv
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon.,Division of Neuroscience, National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon
| | - Jian Qiu
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon
| | - Martin J Kelly
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon.,Division of Neuroscience, National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon
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Leptin actions through the nitrergic system to modulate the hypothalamic expression of the kiss1 mRNA in the female rat. Brain Res 2019; 1728:146574. [PMID: 31790683 DOI: 10.1016/j.brainres.2019.146574] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/05/2019] [Accepted: 11/28/2019] [Indexed: 11/22/2022]
Abstract
Gonadotrophin-releasing hormone (GnRH) is the main controller of the reproductive axis and stimulates the synthesis and secretion of gonadotrophins. Estrogen is the main peripheral factor controlling GnRH secretion, and this action is mainly mediated by the transsynaptic pathway through nitric oxide, kisspeptin, leptin, among other factors. Kisspeptin is the most potent factor known to induce GnRH release. Nitric oxide and leptin also promote GnRH release; however, neurons expressing GnRH do not express the leptin receptor (OB-R). Leptin seems to modulate the expression of genes and proteins involved in the kisspeptin system. However, few kisspeptin-synthesizing cells in the arcuate nucleus (ARC) and few cells, if any, in the preoptic area (POA) express OB-R; this indicates an indirect mechanism of leptin action on kisspeptin. Nitric oxide is an important intermediate in the actions of leptin in the central nervous system. Thus, this work aimed to verify the numbers of nNOS cells were activated by leptin in different hypothalamic areas; the modulatory effects of the nitrergic system on the kisspeptin system; and the indirect regulatory effect of leptin on the kisspeptin system via nitric oxide. Ovariectomized rats were treated with estrogen or a vehicle and received an intracerebroventricular (i.c.v.) injection of a nitric oxide donor, leptin or neuronal nitric oxide synthase (nNOS) enzyme inhibitor. Thirty minutes after the injection, the animals were decapitated. Leptin acts directly on nitrergic neurons in different hypothalamic regions, and the effects on the ventral premammillary nucleus (PMV) and ventral dorsomedial hypothalamus (vDMH) are enhanced. The use of a nitric oxide donor or the administration of leptin stimulates the expression of the kisspeptin mRNA in the ARC of animals with or without estrogenic action; however, these changes are not observed in the POA. In addition, the action of leptin on the expression of the kisspeptin mRNA in the ARC is blocked by a nitric oxide synthesis inhibitor. We concluded that the effects of leptin on the central nervous system are at least partially mediated by the nitrergic system. Also, nitric oxide acts on the kisspeptin system by modulating the expression of the kisspeptin mRNA, and leptin at least partially modulates the kisspeptin system through the nitrergic system, particularly in the ARC.
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Almabhouh FA, Md Mokhtar AH, Malik IA, Aziz NAAA, Durairajanayagam D, Singh HJ. Leptin and reproductive dysfunction in obese men. Andrologia 2019; 52:e13433. [DOI: 10.1111/and.13433] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/05/2019] [Accepted: 08/12/2019] [Indexed: 12/15/2022] Open
Affiliation(s)
| | | | - Ifrah Alam Malik
- Faculty of Medicine Universiti Teknologi MARA Sungai Buloh Malaysia
| | | | | | - Harbindar Jeet Singh
- Faculty of Medicine Universiti Teknologi MARA Sungai Buloh Malaysia
- I‐PerFForm Faculty of Medicine Universiti Teknologi MARA Sungai Buloh Malaysia
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29
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Zhang J, Yin W, Li P, Hu C, Wang L, Li T, Gao E, Hou J, Wang G, Wang X, Wang L, Yu Z, Yuan J. Interaction between diet- and exercise-lifestyle and phthalates exposure on sex hormone levels. JOURNAL OF HAZARDOUS MATERIALS 2019; 369:290-298. [PMID: 30780025 DOI: 10.1016/j.jhazmat.2019.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 01/07/2019] [Accepted: 02/04/2019] [Indexed: 05/24/2023]
Abstract
Phthalate can affect sex hormones secretion. Exercise and diet habits affect sex hormones levels. However, interaction of phthalates exposure and diet or exercise habits with sex hormones is unclear. We enrolled 106 residents aged 11-88 years (48 males and 58 females) from two communities, Wuhan city, China during the winter of 2014 and summer of 2015. Data were collected on socio-demographic characteristics and lifestyle by a questionnaire in two seasons. Participants provided the blood and urine samples over 3 consecutive days for measuring sex hormones and urinary phthalate metabolites. We assessed the associations of urinary phthalate metabolites levels, lifestyle with hormones levels, the interaction of phthalate exposure and lifestyle with hormones levels using multivariate binary logistic regression models. High urinary mono-(2-ethyl-5-oxyhexyl) phthalate (MEOHP) levels and no exercise had an additive interaction on abnormal serum progesterone (PROG) levels in winter as well as on abnormal serum follicle-stimulating hormone (FSH) or luteinizing hormone (LH) levels in summer. High urinary MEOHP levels and red meat intake (>1 time/day) had an additive interaction with abnormal levels of serum FSH only in the winter. Phthalates exposure may confer differential susceptibility to abnormal hormones levels in individuals with no exercise or eating meat >1 time/day.
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Affiliation(s)
- Jiafei Zhang
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Wenjun Yin
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Pei Li
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, PR China
| | - Chen Hu
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Lu Wang
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Tian Li
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Erwei Gao
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Jian Hou
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Guiyang Wang
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Xian Wang
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Lin Wang
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China
| | - Zhiqiang Yu
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, PR China.
| | - Jing Yuan
- Department of Occupational and Environmental Health, PR China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, PR China.
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30
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Garcia-Galiano D, Borges BC, Allen SJ, Elias CF. PI3K signalling in leptin receptor cells: Role in growth and reproduction. J Neuroendocrinol 2019; 31:e12685. [PMID: 30618188 PMCID: PMC6533139 DOI: 10.1111/jne.12685] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/04/2019] [Accepted: 01/04/2019] [Indexed: 12/15/2022]
Abstract
Nutrition and growth are important signals for pubertal development, although how they are perceived and integrated in brain circuits has not been well defined. Growth hormones and metabolic cues both recruit phosphatidylinositol 3-kinase (PI3K) signalling in hypothalamic sites, although whether they converge into the same neuronal population(s) is also not known. In this review, we discuss recent findings from our laboratory showing the role of PI3K subunits in cells directly responsive to the adipocyte-derived hormone leptin in the coordination of growth, pubertal development and fertility. Mice with deletion of PI3K p110α and p110β catalytic subunits in leptin receptor cells (LRΔα+β ) have a lean phenotype associated with increased energy expenditure, locomotor activity and thermogenesis. The LRΔα+β mice also show deficient growth and delayed puberty. Deletion of a single subunit (ie, p110α) in LR cells (LRΔα ) causes a similar phenotype of increased energy expenditure, deficient growth and delayed pubertal development, indicating that these functions are preferably controlled by p110α. The LRΔα mice show enhanced leptin sensitivity in metabolic regulation but, remarkably, these mice are unresponsive to the effects of leptin on growth and puberty. PI3K is also recruited by insulin and a subpopulation of LR neurones is responsive to i.c.v. insulin administration. Deletion of insulin receptor in LR cells causes no changes in body weight or linear growth and induces only a mild delay in pubertal completion. Our findings demonstrate that PI3K in LR cells plays an essential role in growth and reproduction. We will also discuss the potential neural pathways underlying these effects.
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Affiliation(s)
- David Garcia-Galiano
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Beatriz C. Borges
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Susan J. Allen
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Carol F. Elias
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA
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31
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Hill JW, Elias CF. Neuroanatomical Framework of the Metabolic Control of Reproduction. Physiol Rev 2019; 98:2349-2380. [PMID: 30109817 DOI: 10.1152/physrev.00033.2017] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A minimum amount of energy is required for basic physiological processes, such as protein biosynthesis, thermoregulation, locomotion, cardiovascular function, and digestion. However, for reproductive function and survival of the species, extra energy stores are necessary. Production of sex hormones and gametes, pubertal development, pregnancy, lactation, and parental care all require energy reserves. Thus the physiological systems that control energy homeostasis and reproductive function coevolved in mammals to support both individual health and species subsistence. In this review, we aim to gather scientific knowledge produced by laboratories around the world on the role of the brain in integrating metabolism and reproduction. We describe essential neuronal networks, highlighting key nodes and potential downstream targets. Novel animal models and genetic tools have produced substantial advances, but critical gaps remain. In times of soaring worldwide obesity and metabolic dysfunction, understanding the mechanisms by which metabolic stress alters reproductive physiology has become crucial for human health.
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Affiliation(s)
- Jennifer W Hill
- Center for Diabetes and Endocrine Research, Departments of Physiology and Pharmacology and of Obstetrics and Gynecology, University of Toledo College of Medicine , Toledo, Ohio ; and Departments of Molecular and Integrative Physiology and of Obstetrics and Gynecology, University of Michigan , Ann Arbor, Michigan
| | - Carol F Elias
- Center for Diabetes and Endocrine Research, Departments of Physiology and Pharmacology and of Obstetrics and Gynecology, University of Toledo College of Medicine , Toledo, Ohio ; and Departments of Molecular and Integrative Physiology and of Obstetrics and Gynecology, University of Michigan , Ann Arbor, Michigan
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32
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33
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Insights into leptin signaling and male reproductive health: the missing link between overweight and subfertility? Biochem J 2018; 475:3535-3560. [DOI: 10.1042/bcj20180631] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/28/2018] [Accepted: 10/19/2018] [Indexed: 12/24/2022]
Abstract
Obesity stands as one of the greatest healthcare challenges of the 21st century. Obesity in reproductive-age men is ever more frequent and is reaching upsetting levels. At the same time, fertility has taken an inverse direction and is decreasing, leading to an increased demand for fertility treatments. In half of infertile couples, there is a male factor alone or combined with a female factor. Furthermore, male fertility parameters such as sperm count and concentration went on a downward spiral during the last few decades and are now approaching the minimum levels established to achieve successful fertilization. Hence, the hypothesis that obesity and deleterious effects in male reproductive health, as reflected in deterioration of sperm parameters, are somehow related is tempting. Most often, overweight and obese individuals present leptin levels directly proportional to the increased fat mass. Leptin, besides the well-described central hypothalamic effects, also acts in several peripheral organs, including the testes, thus highlighting a possible regulatory role in male reproductive function. In the last years, research focusing on leptin effects in male reproductive function has unveiled additional roles and molecular mechanisms of action for this hormone at the testicular level. Herein, we summarize the novel molecular signals linking metabolism and male reproductive function with a focus on leptin signaling, mitochondria and relevant pathways for the nutritional support of spermatogenesis.
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34
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Evans MC, Anderson GM. Integration of Circadian and Metabolic Control of Reproductive Function. Endocrinology 2018; 159:3661-3673. [PMID: 30304391 DOI: 10.1210/en.2018-00691] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/03/2018] [Indexed: 12/11/2022]
Abstract
Optimal fertility in humans and animals relies on the availability of sufficient metabolic fuels, information about which is communicated to the brain via levels of the hormones leptin and insulin. The circadian clock system is also critical; this input is especially evident in the precise timing of the female-specific surge of GnRH and LH secretion that triggers ovulation the next day. Chronodisruption and metabolic imbalance can both impair reproductive activity, and these two disruptions exacerbate each other, such that they often occur simultaneously. Kisspeptin neurons located in the anteroventral periventricular nucleus of the hypothalamus are able to integrate both circadian and metabolic afferent inputs and use this information to modulate the timing and magnitude of the preovulatory GnRH/LH surge. In an environment in which exposure to high caloric diets and chronodisruptors such as artificial night lighting, shift work, and transmeridian travel have become the norm, the implications of these factors for couples struggling to conceive deserve closer attention and more public education.
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Affiliation(s)
- Maggie C Evans
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Greg M Anderson
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
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35
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Scott CJ, Rose JL, Gunn AJ, McGrath BM. Kisspeptin and the regulation of the reproductive axis in domestic animals. J Endocrinol 2018; 240:JOE-18-0485.R1. [PMID: 30400056 DOI: 10.1530/joe-18-0485] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/09/2018] [Indexed: 11/08/2022]
Abstract
The control of reproductive processes involves the integration of a number of factors from the internal and external environment, with the final output signal of these processes being the pulsatile secretion of gonadotrophin releasing hormone (GnRH) from the hypothalamus. These factors include the feedback actions of sex steroids, feed intake and nutritional status, season/photoperiod, pheromones, age and stress. Understanding these factors and how they influence GnRH secretion and hence reproduction is important for the management of farm animals. There is evidence that the RF-amide neuropeptide, kisspeptin, may be involved in relaying the effects of these factors to the GnRH neurons. This paper will review the evidence from the common domestic animals (sheep, goats, cattle, horses and pigs), that kisspeptin neurons are i) regulated by the factors listed above, ii) contact GnRH neurons, and iii) involved in the regulation of GnRH/gonadotrophin secretion.
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Affiliation(s)
- Christopher J Scott
- C Scott, School of Biomedical Sciences, Charles Sturt University - Wagga Wagga Campus, Wagga Wagga, Australia
| | - Jessica L Rose
- J Rose, School of Biomedical Sciences, Charles Sturt University - Wagga Wagga Campus, Wagga Wagga, Australia
| | - Allan J Gunn
- A Gunn, School of Animal and Veterinary Sciences, Charles Sturt University - Wagga Wagga Campus, Wagga Wagga, Australia
| | - Briony M McGrath
- B McGrath, School of Biomedical Sciences, Charles Sturt University - Wagga Wagga Campus, Wagga Wagga, Australia
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36
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Nestor CC, Bedenbaugh MN, Hileman SM, Coolen LM, Lehman MN, Goodman RL. Regulation of GnRH pulsatility in ewes. Reproduction 2018; 156:R83-R99. [PMID: 29880718 DOI: 10.1530/rep-18-0127] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/07/2018] [Indexed: 01/21/2023]
Abstract
Early work in ewes provided a wealth of information on the physiological regulation of pulsatile gonadotropin-releasing hormone (GnRH) secretion by internal and external inputs. Identification of the neural systems involved, however, was limited by the lack of information on neural mechanisms underlying generation of GnRH pulses. Over the last decade, considerable evidence supported the hypothesis that a group of neurons in the arcuate nucleus that contain kisspeptin, neurokinin B and dynorphin (KNDy neurons) are responsible for synchronizing secretion of GnRH during each pulse in ewes. In this review, we describe our current understanding of the neural systems mediating the actions of ovarian steroids and three external inputs on GnRH pulsatility in light of the hypothesis that KNDy neurons play a key role in GnRH pulse generation. In breeding season adults, estradiol (E2) and progesterone decrease GnRH pulse amplitude and frequency, respectively, by actions on KNDy neurons, with E2 decreasing kisspeptin and progesterone increasing dynorphin release onto GnRH neurons. In pre-pubertal lambs, E2 inhibits GnRH pulse frequency by decreasing kisspeptin and increasing dynorphin release, actions that wane as the lamb matures to allow increased pulsatile GnRH secretion at puberty. Less is known about mediators of undernutrition and stress, although some evidence implicates kisspeptin and dynorphin, respectively, in the inhibition of GnRH pulse frequency by these factors. During the anoestrus, inhibitory photoperiod acting via melatonin activates A15 dopaminergic neurons that innervate KNDy neurons; E2 increases dopamine release from these neurons to inhibit KNDy neurons and suppress the frequency of kisspeptin and GnRH release.
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Affiliation(s)
- Casey C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, North Carolina, USA
| | - Michelle N Bedenbaugh
- Department of Physiology, Pharmacology and Neuroscience, West Virginia University, Morgantown, West Virginia, USA
| | - Stanley M Hileman
- Department of Physiology, Pharmacology and Neuroscience, West Virginia University, Morgantown, West Virginia, USA
| | - Lique M Coolen
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA.,Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Michael N Lehman
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Robert L Goodman
- Department of Physiology, Pharmacology and Neuroscience, West Virginia University, Morgantown, West Virginia, USA
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Sominsky L, Jasoni CL, Twigg HR, Spencer SJ. Hormonal and nutritional regulation of postnatal hypothalamic development. J Endocrinol 2018; 237:R47-R64. [PMID: 29545398 DOI: 10.1530/joe-17-0722] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 03/15/2018] [Indexed: 12/24/2022]
Abstract
The hypothalamus is a key centre for regulation of vital physiological functions, such as appetite, stress responsiveness and reproduction. Development of the different hypothalamic nuclei and its major neuronal populations begins prenatally in both altricial and precocial species, with the fine tuning of neuronal connectivity and attainment of adult function established postnatally and maintained throughout adult life. The perinatal period is highly susceptible to environmental insults that, by disrupting critical developmental processes, can set the tone for the establishment of adult functionality. Here, we review the most recent knowledge regarding the major postnatal milestones in the development of metabolic, stress and reproductive hypothalamic circuitries, in the rodent, with a particular focus on perinatal programming of these circuitries by hormonal and nutritional influences. We also review the evidence for the continuous development of the hypothalamus in the adult brain, through changes in neurogenesis, synaptogenesis and epigenetic modifications. This degree of plasticity has encouraging implications for the ability of the hypothalamus to at least partially reverse the effects of perinatal mal-programming.
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Affiliation(s)
- Luba Sominsky
- School of Health and Biomedical SciencesRMIT University, Melbourne, Victoria, Australia
| | - Christine L Jasoni
- School of Biomedical SciencesCentre for Neuroendocrinology, Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Hannah R Twigg
- School of Biomedical SciencesCentre for Neuroendocrinology, Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Sarah J Spencer
- School of Health and Biomedical SciencesRMIT University, Melbourne, Victoria, Australia
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Wolfe A, Hussain MA. The Emerging Role(s) for Kisspeptin in Metabolism in Mammals. Front Endocrinol (Lausanne) 2018; 9:184. [PMID: 29740399 PMCID: PMC5928256 DOI: 10.3389/fendo.2018.00184] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/05/2018] [Indexed: 12/17/2022] Open
Abstract
Kisspeptin was initially identified as a metastasis suppressor. Shortly after the initial discovery, a key physiologic role for kisspeptin emerged in the regulation of fertility, with kisspeptin acting as a neurotransmitter via the kisspeptin receptor, its cognate receptor, to regulate hypothalamic GnRH neurons, thereby affecting pituitary-gonadal function. Recent work has demonstrated a more expansive role for kisspeptin signaling in a variety of organ systems. Kisspeptin has been revealed as a significant player in regulating glucose homeostasis, feeding behavior, body composition as well as cardiac function. The direct impact of kisspeptin on peripheral metabolic tissues has only recently been recognized. Here, we review the emerging endocrine role of kisspeptin in regulating metabolic function. Controversies and current limitations in the field as well as areas of future studies toward kisspeptin's diverse array of functions will be highlighted.
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Affiliation(s)
- Andrew Wolfe
- Department of Pediatrics, Johns Hopkins University, Baltimore, MD, United States
| | - Mehboob A. Hussain
- Department of Internal Medicine Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, United States
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Avendaño MS, Vazquez MJ, Tena-Sempere M. Disentangling puberty: novel neuroendocrine pathways and mechanisms for the control of mammalian puberty. Hum Reprod Update 2018; 23:737-763. [PMID: 28961976 DOI: 10.1093/humupd/dmx025] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 08/01/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Puberty is a complex developmental event, controlled by sophisticated regulatory networks that integrate peripheral and internal cues and impinge at the brain centers driving the reproductive axis. The tempo of puberty is genetically determined but is also sensitive to numerous modifiers, from metabolic and sex steroid signals to environmental factors. Recent epidemiological evidence suggests that the onset of puberty is advancing in humans, through as yet unknown mechanisms. In fact, while much knowledge has been gleaned recently on the mechanisms responsible for the control of mammalian puberty, fundamental questions regarding the intimate molecular and neuroendocrine pathways responsible for the precise timing of puberty and its deviations remain unsolved. OBJECTIVE AND RATIONALE By combining data from suitable model species and humans, we aim to provide a comprehensive summary of our current understanding of the neuroendocrine mechanisms governing puberty, with particular focus on its central regulatory pathways, underlying molecular basis and mechanisms for metabolic control. SEARCH METHODS A comprehensive MEDLINE search of articles published mostly from 2003 to 2017 has been carried out. Data from cellular and animal models (including our own results) as well as clinical studies focusing on the pathophysiology of puberty in mammals were considered and cross-referenced with terms related with central neuroendocrine mechanisms, metabolic control and epigenetic/miRNA regulation. OUTCOMES Studies conducted during the last decade have revealed the essential role of novel central neuroendocrine pathways in the control of puberty, with a prominent role of kisspeptins in the precise regulation of the pubertal activation of GnRH neurosecretory activity. In addition, different transmitters, including neurokinin-B (NKB) and, possibly, melanocortins, have been shown to interplay with kisspeptins in tuning puberty onset. Alike, recent studies have documented the role of epigenetic mechanisms, involving mainly modulation of repressors that target kisspeptins and NKB pathways, as well as microRNAs and the related binding protein, Lin28B, in the central control of puberty. These novel pathways provide the molecular and neuroendocrine basis for the modulation of puberty by different endogenous and environmental cues, including nutritional and metabolic factors, such as leptin, ghrelin and insulin, which are known to play an important role in pubertal timing. WIDER IMPLICATIONS Despite recent advancements, our understanding of the basis of mammalian puberty remains incomplete. Complete elucidation of the novel neuropeptidergic and molecular mechanisms summarized in this review will not only expand our knowledge of the intimate mechanisms responsible for puberty onset in humans, but might also provide new tools and targets for better prevention and management of pubertal deviations in the clinical setting.
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Affiliation(s)
- M S Avendaño
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, Faculty of Medicine, University of Córdoba, Avda. Menéndez Pidal s/n. 14004 Córdoba, Spain.,Hospital Universitario Reina Sofia, Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain
| | - M J Vazquez
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, Faculty of Medicine, University of Córdoba, Avda. Menéndez Pidal s/n. 14004 Córdoba, Spain.,Hospital Universitario Reina Sofia, Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain
| | - M Tena-Sempere
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, Faculty of Medicine, University of Córdoba, Avda. Menéndez Pidal s/n. 14004 Córdoba, Spain.,Hospital Universitario Reina Sofia, Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Avda. Menéndez Pidal, s/n, 14004 Córdoba, Spain.,FiDiPro Program, Department of Physiology, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland
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Thorson JF, Prezotto LD, Adams H, Petersen SL, Clapper JA, Wright EC, Oliver WT, Freking BA, Foote AP, Berry ED, Nonneman DJ, Lents CA. Energy balance affects pulsatile secretion of luteinizing hormone from the adenohypophesis and expression of neurokinin B in the hypothalamus of ovariectomized gilts†. Biol Reprod 2018; 99:433-445. [DOI: 10.1093/biolre/ioy069] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/20/2018] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Ligia D Prezotto
- Nutritional & Reproductive Physiology Laboratory, Montana State University, Havre, Montana, USA
| | - Hillary Adams
- Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Sandra L Petersen
- Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Jeffrey A Clapper
- Animal Science, South Dakota State University, Brookings, South Dakota, USA
| | - Elane C Wright
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - William T Oliver
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - Bradley A Freking
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - Andrew P Foote
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - Elaine D Berry
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - Danny J Nonneman
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - Clay A Lents
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
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Pérez‐Pérez A, Toro A, Vilariño‐García T, Maymó J, Guadix P, Dueñas JL, Fernández‐Sánchez M, Varone C, Sánchez‐Margalet V. Leptin action in normal and pathological pregnancies. J Cell Mol Med 2018; 22:716-727. [PMID: 29160594 PMCID: PMC5783877 DOI: 10.1111/jcmm.13369] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 07/10/2017] [Indexed: 12/11/2022] Open
Abstract
Leptin is now considered an important signalling molecule of the reproductive system, as it regulates the production of gonadotrophins, the blastocyst formation and implantation, the normal placentation, as well as the foeto-placental communication. Leptin is a peptide hormone secreted mainly by adipose tissue, and the placenta is the second leptin-producing tissue in humans. Placental leptin is an important cytokine which regulates placental functions in an autocrine or paracrine manner. Leptin seems to play a crucial role during the first stages of pregnancy as it modulates critical processes such as proliferation, protein synthesis, invasion and apoptosis in placental cells. Furthermore, deregulation of leptin levels has been correlated with the pathogenesis of various disorders associated with reproduction and gestation, including polycystic ovary syndrome, recurrent miscarriage, gestational diabetes mellitus, pre-eclampsia and intrauterine growth restriction. Due to the relevant incidence of the mentioned diseases and the importance of leptin, we decided to review the latest information available about leptin action in normal and pathological pregnancies to support the idea of leptin as an important factor and/or predictor of diverse disorders associated with reproduction and pregnancy.
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Affiliation(s)
- Antonio Pérez‐Pérez
- Department of Medical Biochemistry and Molecular BiologyVirgen Macarena University HospitalUniversity of SevilleSevilleSpain
| | - Ayelén Toro
- Laboratory of Placental Molecular PhysiologyDepartment of Biological ChemistrySchool of SciencesUniversity of Buenos AiresIQUIBICEN‐CONICETBuenos AiresArgentina
| | - Teresa Vilariño‐García
- Department of Medical Biochemistry and Molecular BiologyVirgen Macarena University HospitalUniversity of SevilleSevilleSpain
| | - Julieta Maymó
- Laboratory of Placental Molecular PhysiologyDepartment of Biological ChemistrySchool of SciencesUniversity of Buenos AiresIQUIBICEN‐CONICETBuenos AiresArgentina
| | - Pilar Guadix
- Department of Obstetrics and GynecologyVirgen Macarena University HospitalUniversity of SevilleSevilleSpain
| | - José L. Dueñas
- Department of Obstetrics and GynecologyVirgen Macarena University HospitalUniversity of SevilleSevilleSpain
| | | | - Cecilia Varone
- Laboratory of Placental Molecular PhysiologyDepartment of Biological ChemistrySchool of SciencesUniversity of Buenos AiresIQUIBICEN‐CONICETBuenos AiresArgentina
| | - Víctor Sánchez‐Margalet
- Department of Medical Biochemistry and Molecular BiologyVirgen Macarena University HospitalUniversity of SevilleSevilleSpain
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Manfredi-Lozano M, Roa J, Tena-Sempere M. Connecting metabolism and gonadal function: Novel central neuropeptide pathways involved in the metabolic control of puberty and fertility. Front Neuroendocrinol 2018; 48:37-49. [PMID: 28754629 DOI: 10.1016/j.yfrne.2017.07.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/20/2017] [Accepted: 07/23/2017] [Indexed: 02/08/2023]
Abstract
Albeit essential for perpetuation of species, reproduction is an energy-demanding function that can be adjusted to body metabolic status. Reproductive maturation and function can be suppressed in conditions of energy deficit, but can be altered also in situations of persistent energy excess, e.g., morbid obesity. This metabolic-reproductive integration, of considerable pathophysiological relevance to explain different forms of perturbed puberty and sub/infertility, is implemented by the concerted action of numerous central and peripheral regulators, which impinge at different levels of the hypothalamic-pituitary-gonadal (HPG) axis, permitting a tight fit between nutritional/energy status and gonadal function. We summarize here the major physiological mechanisms whereby nutritional and metabolic cues modulate the maturation and function of the HPG axis. We will focus on recent progress on the major central neuropeptide pathways, including kisspeptins, neurokinin B and the products of POMC and NPY neurons, which convey metabolic information to GnRH neurons, as major hierarchical hub of our reproductive brain.
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Affiliation(s)
- M Manfredi-Lozano
- Instituto Maimónides de Investigación Biomédica de Cordoba (IMIBIC), Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, Spain; Hospital Universitario Reina Sofia, 14004 Cordoba, Spain; Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Centre, INSERM, U1172, Lille, France
| | - J Roa
- Instituto Maimónides de Investigación Biomédica de Cordoba (IMIBIC), Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, Spain; Hospital Universitario Reina Sofia, 14004 Cordoba, Spain.
| | - M Tena-Sempere
- Instituto Maimónides de Investigación Biomédica de Cordoba (IMIBIC), Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, Spain; Hospital Universitario Reina Sofia, 14004 Cordoba, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 14004 Cordoba, Spain; FiDiPro Program, Department of Physiology, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland.
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Wahab F, Atika B, Ullah F, Shahab M, Behr R. Metabolic Impact on the Hypothalamic Kisspeptin-Kiss1r Signaling Pathway. Front Endocrinol (Lausanne) 2018; 9:123. [PMID: 29643834 PMCID: PMC5882778 DOI: 10.3389/fendo.2018.00123] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/12/2018] [Indexed: 12/12/2022] Open
Abstract
A large body of data has established the hypothalamic kisspeptin (KP) and its receptor, KISS1R, as major players in the activation of the neuroendocrine reproductive axis at the time of puberty and maintenance of reproductive capacity in the adult. Due to its strategic location, this ligand-receptor pair acts as an integrator of cues from gonadal steroids as well as of circadian and seasonal variation-related information on the reproductive axis. Besides these cues, the activity of the hypothalamic KP signaling is very sensitive to the current metabolic status of the body. In conditions of energy imbalance, either positive or negative, a number of alterations in the hypothalamic KP signaling pathway have been documented in different mammalian models including nonhuman primates and human. Deficiency of metabolic fuels during fasting causes a marked reduction of Kiss1 gene transcript levels in the hypothalamus and, hence, decreases the output of KP-containing neurons. Food intake or exogenous supply of metabolic cues, such as leptin, reverses metabolic insufficiency-related changes in the hypothalamic KP signaling. Likewise, alterations in Kiss1 expression have also been reported in other situations of energy imbalance like diabetes and obesity. Information related to the body's current metabolic status reaches to KP neurons both directly as well as indirectly via a complex network of other neurons. In this review article, we have provided an updated summary of the available literature on the regulation of the hypothalamic KP-Kiss1r signaling by metabolic cues. In particular, the potential mechanisms of metabolic impact on the hypothalamic KP-Kiss1r signaling, in light of available evidence, are discussed.
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Affiliation(s)
- Fazal Wahab
- Platform Degenerative Diseases, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
- *Correspondence: Fazal Wahab,
| | - Bibi Atika
- Department of Developmental Biology, Faculty of Biology, University of Göttingen, Göttingen, Germany
| | - Farhad Ullah
- Department of Zoology, Islamia College University, Peshawar, Pakistan
| | - Muhammad Shahab
- Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quiad-i-Azam University, Islamabad, Pakistan
| | - Rüdiger Behr
- Platform Degenerative Diseases, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
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Nakao K, Iwata K, Takeshita T, Ozawa H. Expression of hypothalamic kisspeptin, neurokinin B, and dynorphin A neurons attenuates in female Zucker fatty rats. Neurosci Lett 2017; 665:135-139. [PMID: 29203206 DOI: 10.1016/j.neulet.2017.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 11/25/2017] [Accepted: 12/01/2017] [Indexed: 10/18/2022]
Abstract
Zucker fatty (ZF) rats are considered to be an obese model due to leptin receptor abnormality and such rats show infertility. Pulsatile gonadotropin-releasing hormone/luteinizing hormone (LH) secretion, which is important for follicular development in females, is considered to be controlled by KNDy neurons coexpressing kisspeptin, neurokinin B (NKB), and dynorphin A (DynA), encoded by Kiss1, Tac3, and Pdyn, respectively, in the hypothalamic arcuate nucleus (ARC). The purpose of this study is to examine the expression of KNDy neurons in female ZF rats by histochemical approach because pulsatile LH secretion is suppressed. Zucker lean (ZL) rats served as a control group. Animals were ovariectomized and subcutaneously implanted with a silicon tube containing estradiol to produce plasma level of estradiol during diestrus. Plasma LH levels decreased in ZF rats compared with ZL rats. The expressions of each mRNA (Kiss1, Tac3, and Pdyn) and each peptide (kisspeptin, NKB, and DynA) in the ARC significantly decreased in ZF rats compared with ZL rats. However, the number of Kiss1 neurons in the anterior ventral periventricular nucleus did not significantly differ between the two groups. These results suggest that dysfunction of leptin signaling negatively affects KNDy neurons in the ARC, resulting in reproductive dysfunction caused by suppression of the LH pulse.
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Affiliation(s)
- Kimihiko Nakao
- Department of Reproductive Medicine, Perinatology and Gynecologic Oncology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo 113-8602, Japan
| | - Kinuyo Iwata
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo 113-8602, Japan
| | - Toshiyuki Takeshita
- Department of Reproductive Medicine, Perinatology and Gynecologic Oncology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo 113-8602, Japan
| | - Hitoshi Ozawa
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo 113-8602, Japan.
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Venancio JC, Margatho LO, Rorato R, Rosales RRC, Debarba LK, Coletti R, Antunes-Rodrigues J, Elias CF, Elias LLK. Short-Term High-Fat Diet Increases Leptin Activation of CART Neurons and Advances Puberty in Female Mice. Endocrinology 2017; 158:3929-3942. [PMID: 28938405 PMCID: PMC5695829 DOI: 10.1210/en.2017-00452] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/30/2017] [Indexed: 11/19/2022]
Abstract
Leptin is a permissive factor for puberty initiation, participating as a metabolic cue in the activation of the kisspeptin (Kiss1)-gonadotropin-releasing hormone neuronal circuitry; however, it has no direct effect on Kiss1 neurons. Leptin acts on hypothalamic cocaine- and amphetamine-regulated transcript (CART) neurons, participating in the regulation of energy homeostasis. We investigated the influence of a short-term high-fat diet (HFD) on the effect of leptin on puberty timing. Kiss1-hrGFP female mice received a HFD or regular diet (RD) after weaning at postnatal day (PN)21 and were studied at PN28 and PN32. The HFD increased body weight and plasma leptin concentrations and decreased the age at vaginal opening (HFD, 32 ± 0.53 days; RD, 38 ± 0.67 days). Similar colocalization of neurokinin B and dynorphin in Kiss1-hrGFP neurons of the arcuate nucleus (ARC) was observed between the HFD and RD groups. The HFD increased CART expression in the ARC and Kiss1 messenger RNA expression in the anteroventral periventricular (AVPV)/anterior periventricular (Pe). The HFD also increased the number of ARC CART neurons expressing leptin-induced phosphorylated STAT3 (signal transducer and activator of transcription 3) at PN32. Close apposition of CART fibers to Kiss1-hrGFP neurons was observed in the ARC of both RD- and HFD-fed mice. In conclusion, these data reinforce the notion that a HFD increases kisspeptin expression in the AVPV/Pe and advances puberty initiation. Furthermore, we have demonstrated that the HFD-induced earlier puberty is associated with an increase in CART expression in the ARC. Therefore, these data indicate that CART neurons in the ARC can mediate the effect of leptin on Kiss1 neurons in early puberty induced by a HFD.
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Affiliation(s)
- Jade Cabestre Venancio
- Department of Physiology, Ribeirao Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
| | - Lisandra Oliveira Margatho
- Department of Physiology, Ribeirao Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
| | - Rodrigo Rorato
- Department of Physiology, Ribeirao Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
| | | | - Lucas Kniess Debarba
- Department of Physiology, Ribeirao Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
| | - Ricardo Coletti
- Department of Physiology, Ribeirao Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
| | - Jose Antunes-Rodrigues
- Department of Physiology, Ribeirao Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
| | - Carol F. Elias
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Lucila Leico K. Elias
- Department of Physiology, Ribeirao Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
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Chachlaki K, Garthwaite J, Prevot V. The gentle art of saying NO: how nitric oxide gets things done in the hypothalamus. Nat Rev Endocrinol 2017. [PMID: 28621341 DOI: 10.1038/nrendo.2017.69] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The chemical signalling molecule nitric oxide (NO), which freely diffuses through aqueous and lipid environments, subserves an array of functions in the mammalian central nervous system, such as the regulation of synaptic plasticity, blood flow and neurohormone secretion. In this Review, we consider the cellular and molecular mechanisms by which NO evokes short-term and long-term changes in neuronal activity. We also highlight recent studies showing that discrete populations of neurons that synthesize NO in the hypothalamus constitute integrative systems that support life by relaying metabolic and gonadal signals to the neuroendocrine brain, and thus gate the onset of puberty and adult fertility. The putative involvement and therapeutic potential of NO in the pathophysiology of brain diseases, for which hormonal imbalances during postnatal development could be risk factors, is also discussed.
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Affiliation(s)
- Konstantina Chachlaki
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Centre, UMR-S 1172, 1 place de Verdun, F-59000 Lille, France
- University of Lille, University Hospital Federations (FHU) 1,000 days for Health, School of Medicine, 1 place de Verdun, F-59000 Lille, France
| | - John Garthwaite
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
| | - Vincent Prevot
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Centre, UMR-S 1172, 1 place de Verdun, F-59000 Lille, France
- University of Lille, University Hospital Federations (FHU) 1,000 days for Health, School of Medicine, 1 place de Verdun, F-59000 Lille, France
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Deletion of Suppressor of Cytokine Signaling 3 from Forebrain Neurons Delays Infertility and Onset of Hypothalamic Leptin Resistance in Response to a High Caloric Diet. J Neurosci 2017; 36:7142-53. [PMID: 27383590 DOI: 10.1523/jneurosci.2714-14.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 05/27/2016] [Indexed: 12/19/2022] Open
Abstract
UNLABELLED The cellular processes that cause high caloric diet (HCD)-induced infertility are poorly understood but may involve upregulation of suppressor of cytokine signaling (SOCS-3) proteins that are associated with hypothalamic leptin resistance. Deletion of SOCS-3 from brain cells is known to protect mice from diet-induced obesity, but the effects on HCD-induced infertility are unknown. We used neuron-specific SOCS3 knock-out mice to elucidate this and the effects on regional hypothalamic leptin resistance. As expected, male and female neuron-specific SOCS3 knock-out mice were protected from HCD-induced obesity. While female wild-type mice became infertile after 4 months of HCD feeding, infertility onset in knock-out females was delayed by 4 weeks. Similarly, knock-out mice had delayed leptin resistance development in the medial preoptic area and anteroventral periventricular nucleus, regions important for generation of the surge of GnRH and LH that induces ovulation. We therefore tested whether the suppressive effects of HCD on the estradiol-induced GnRH/LH surge were overcome by neuron-specific SOCS3 knock-out. Although only 20% of control HCD-mice experienced a preovulatory-like LH surge, LH surges could be induced in almost all neuron-specific SOCS3 knock-out mice on this diet. In contrast to females, HCD-fed male mice did not exhibit any fertility decline compared with low caloric diet-fed males despite their resistance to the satiety effects of leptin. These data show that deletion of SOCS3 delays the onset of leptin resistance and infertility in HCD-fed female mice, but given continued HCD feeding this state does eventually occur, presumably in response to other mechanisms inhibiting leptin signal transduction. SIGNIFICANCE STATEMENT Obesity is commonly associated with infertility in humans and other animals. Treatments for human infertility show a decreased success rate with increasing body mass index. A hallmark of obesity is an increase in circulating leptin levels; despite this, the brain responds as if there were low levels of leptin, leading to increased appetite and suppressed fertility. Here we show that leptin resistant infertility is caused in part by the leptin signaling molecule SOCS3. Deletion of SOCS3 from brain neurons delays the onset of diet-induced infertility.
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Busby ER, Sherwood NM. Gonadotropin-releasing hormone receptor (Gnrhr) gene knock out: Normal growth and development of sensory, motor and spatial orientation behavior but altered metabolism in neonatal and prepubertal mice. PLoS One 2017; 12:e0174452. [PMID: 28346489 PMCID: PMC5367835 DOI: 10.1371/journal.pone.0174452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/09/2017] [Indexed: 11/27/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is important in the control of reproduction, but its actions in non-reproductive processes are less well known. In this study we examined the effect of disrupting the GnRH receptor in mice to determine if growth, metabolism or behaviors that are not associated with reproduction were affected. To minimize the effects of other hormones such as FSH, LH and sex steroids, the neonatal-prepubertal period of 2 to 28 days of age was selected. The study shows that regardless of sex or phenotype in the Gnrhr gene knockout line, there was no significant difference in the daily development of motor control, sensory detection or spatial orientation among the wildtype, heterozygous or null mice. This included a series of behavioral tests for touch, vision, hearing, spatial orientation, locomotory behavior and muscle strength. Neither the daily body weight nor the final weight on day 28 of the kidney, liver and thymus relative to body weight varied significantly in any group. However by day 28, metabolic changes in the GnRH null females compared with wildtype females showed a significant reduction in inguinal fat pad weight normalized to body weight; this was accompanied by an increase in glucose compared with wildtype females shown by Student-Newman-Keuls Multiple Comparison test and Student's unpaired t tests. Our studies show that the GnRH-GnRHR system is not essential for growth or motor/sensory/orientation behavior during the first month of life prior to puberty onset. The lack of the GnRH-GnRHR axis, however, did affect females resulting in reduced subcutaneous inguinal fat pad weight and increased glucose with possible insulin resistance; the loss of the normal rise of estradiol at postnatal days 15-28 may account for the altered metabolism in the prepubertal female pups.
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Affiliation(s)
- Ellen R. Busby
- Department of Biology, University of Victoria, Victoria, BC, Canada
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Sena GC, Freitas-Lima LC, Merlo E, Podratz PL, de Araújo JF, Brandão PA, Carneiro MT, Zicker MC, Ferreira AV, Takiya CM, de Lemos Barbosa CM, Morales MM, Santos-Silva AP, Miranda-Alves L, Silva IV, Graceli JB. Environmental obesogen tributyltin chloride leads to abnormal hypothalamic-pituitary-gonadal axis function by disruption in kisspeptin/leptin signaling in female rats. Toxicol Appl Pharmacol 2017; 319:22-38. [DOI: 10.1016/j.taap.2017.01.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 01/27/2017] [Accepted: 01/30/2017] [Indexed: 12/15/2022]
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Evans MC, Anderson GM. Neuroendocrine integration of nutritional signals on reproduction. J Mol Endocrinol 2017; 58:R107-R128. [PMID: 28057770 DOI: 10.1530/jme-16-0212] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 01/05/2017] [Indexed: 12/28/2022]
Abstract
Reproductive function in mammals is energetically costly and therefore tightly regulated by nutritional status. To enable this integration of metabolic and reproductive function, information regarding peripheral nutritional status must be relayed centrally to the gonadotropin-releasing hormone (GNRH) neurons that drive reproductive function. The metabolically relevant hormones leptin, insulin and ghrelin have been identified as key mediators of this 'metabolic control of fertility'. However, the neural circuitry through which they act to exert their control over GNRH drive remains incompletely understood. With the advent of Cre-LoxP technology, it has become possible to perform targeted gene-deletion and gene-rescue experiments and thus test the functional requirement and sufficiency, respectively, of discrete hormone-neuron signaling pathways in the metabolic control of reproductive function. This review discusses the findings from these investigations, and attempts to put them in context with what is known from clinical situations and wild-type animal models. What emerges from this discussion is clear evidence that the integration of nutritional signals on reproduction is complex and highly redundant, and therefore, surprisingly difficult to perturb. Consequently, the deletion of individual hormone-neuron signaling pathways often fails to cause reproductive phenotypes, despite strong evidence that the targeted pathway plays a role under normal physiological conditions. Although transgenic studies rarely reveal a critical role for discrete signaling pathways, they nevertheless prove to be a good strategy for identifying whether a targeted pathway is absolutely required, critically involved, sufficient or dispensable in the metabolic control of fertility.
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Affiliation(s)
- Maggie C Evans
- Centre for Neuroendocrinology and Department of AnatomyUniversity of Otago School of Medical Sciences, Dunedin, New Zealand
| | - Greg M Anderson
- Centre for Neuroendocrinology and Department of AnatomyUniversity of Otago School of Medical Sciences, Dunedin, New Zealand
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