scholarly journals Investigating the NPY/AgRP/GABA to GnRH Neuron Circuit in Prenatally Androgenized PCOS-Like Mice

2020 ◽  
Vol 4 (11) ◽  
Author(s):  
Christopher J Marshall ◽  
Melanie Prescott ◽  
Rebecca E Campbell
Keyword(s):  
Polycystic Ovary ◽  
Reproductive Function ◽  
Receptor Expression ◽  
Late Gestation ◽  
Gnrh Neuron ◽  
Androgen Excess ◽  
Neuron Circuit ◽  
Gaba Neurons ◽  
Gnrh Neurons ◽  
Prenatal Androgen

Abstract Polycystic ovary syndrome (PCOS), the most common form of anovulatory infertility, is associated with altered signaling within the hormone-sensitive neuronal network that regulates gonadotropin-releasing hormone (GnRH) neurons, leading to a pathological increase in GnRH secretion. Circuit remodeling is evident between GABAergic neurons in the arcuate nucleus (ARN) and GnRH neurons in a murine model of PCOS. One-third of ARN GABA neurons co-express neuropeptide Y (NPY), which has a known yet complex role in regulating GnRH neurons and reproductive function. Here, we investigated whether the NPY-expressing subpopulation (NPYARN) of ARN GABA neurons (GABAARN) is also affected in prenatally androgenized (PNA) PCOS-like NPYARN reporter mice [Agouti-related protein (AgRP)-Cre;τGFP]. PCOS-like mice and controls were generated by exposure to di-hydrotestosterone or vehicle (VEH) in late gestation. τGFP-expressing NPYARN neuron fiber appositions with GnRH neurons and gonadal steroid hormone receptor expression in τGFP-expressing NPYARN neurons were assessed using confocal microscopy. Although GnRH neurons received abundant close contacts from τGFP-expressing NPYARN neuron fibers, the number and density of putative inputs was not affected by prenatal androgen excess. NPYARN neurons did not co-express progesterone receptor or estrogen receptor α in either PNA or VEH mice. However, the proportion of NPYARN neurons co-expressing the androgen receptor was significantly elevated in PNA mice. Therefore, NPYARN neurons are not remodeled by prenatal androgen excess like the wider GABAARN population, indicating GABA-to-GnRH neuron circuit remodeling occurs in a presently unidentified non-NPY/AgRP population of GABAARN neurons. NPYARN neurons do, however, show independent changes in the form of elevated androgen sensitivity.

scholarly journals Prenatal Androgenization Alters the Development of GnRH Neuron and Preoptic Area RNA Transcripts in Female Mice

Endocrinology ◽  
2020 ◽  
Vol 161 (11) ◽  
Author(s):  
Laura L Burger ◽  
Elizabeth R Wagenmaker ◽  
Chayarndorn Phumsatitpong ◽  
David P Olson ◽  
Suzanne M Moenter
Keyword(s):  
Protein Synthesis ◽  
Oxidative Phosphorylation ◽  
Polycystic Ovary ◽  
Affinity Purification ◽  
Developmental Trajectory ◽  
Late Gestation ◽  
Gnrh Neuron ◽  
Altered Expression ◽  
Increased Risk ◽  
Gnrh Neurons

Abstract Polycystic ovary syndrome (PCOS) is the most common form of infertility in women. The causes of PCOS are not yet understood and both genetics and early-life exposure have been considered as candidates. With regard to the latter, circulating androgens are elevated in mid–late gestation in women with PCOS, potentially exposing offspring to elevated androgens in utero; daughters of women with PCOS are at increased risk for developing this disorder. Consistent with these clinical observations, prenatal androgenization (PNA) of several species recapitulates many phenotypes observed in PCOS. There is increasing evidence that symptoms associated with PCOS, including elevated luteinizing hormone (LH) (and presumably gonadotropin-releasing hormone [GnRH]) pulse frequency emerge during the pubertal transition. We utilized translating ribosome affinity purification coupled with ribonucleic acid (RNA) sequencing to examine GnRH neuron messenger RNAs from prepubertal (3 weeks) and adult female control and PNA mice. Prominent in GnRH neurons were transcripts associated with protein synthesis and cellular energetics, in particular oxidative phosphorylation. The GnRH neuron transcript profile was affected more by the transition from prepuberty to adulthood than by PNA treatment; however, PNA did change the developmental trajectory of GnRH neurons. This included families of transcripts related to both protein synthesis and oxidative phosphorylation, which were more prevalent in adults than in prepubertal mice but were blunted in PNA adults. These findings suggest that prenatal androgen exposure can program alterations in the translatome of GnRH neurons, providing a mechanism independent of changes in the genetic code for altered expression.

scholarly journals The influence of maternal androgen excess on the male reproductive axis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sarah Holland ◽  
Melanie Prescott ◽  
Michael Pankhurst ◽  
Rebecca E. Campbell
Keyword(s):  
Polycystic Ovary ◽  
Critical Role ◽  
Female Offspring ◽  
Confocal Imaging ◽  
Receptor Expression ◽  
Late Gestation ◽  
Plasma Testosterone ◽  
Androgen Excess ◽  
Reproductive Axis ◽  
Pulse Characteristics

AbstractPrenatal androgen excess is suspected to contribute to the development of polycystic ovary syndrome (PCOS) in women. Evidence from preclinical female animal models links maternal androgen excess with the development of PCOS-like features and associated alterations in the neuronal network regulating the reproductive axis. There is some evidence suggesting that maternal androgen excess leads to similar reproductive axis disruptions in men, despite the critical role that androgens play in normal sexual differentiation. Here, the specific impact of maternal androgen excess on the male hypothalamic-pituitary-gonadal axis was investigated using a prenatal androgenization protocol in mice shown to model PCOS-like features in females. Reproductive phenotyping of prenatally androgenised male (PNAM) mice revealed no discernible impact of maternal androgen excess at any level of the reproductive axis. Luteinising hormone pulse characteristics, daily sperm production, plasma testosterone and anti-Müllerian hormone levels were not different in the male offspring of dams administered dihydrotestosterone (DHT) during late gestation compared to controls. Androgen receptor expression was quantified through the hypothalamus and identified as unchanged. Confocal imaging of gonadotropin-releasing hormone (GnRH) neurons revealed that in contrast with prenatally androgenised female mice, PNAM mice exhibited no differences in the density of putative GABAergic innervation compared to controls. These data indicate that a maternal androgen environment capable of inducing reproductive dysfunction in female offspring has no evident impact on the reproductive axis of male littermates in adulthood.

scholarly journals Impairments in the reproductive axis of female mice lacking estrogen receptor β in GnRH neurons

2018 ◽  
Vol 315 (5) ◽  
pp. E1019-E1033 ◽  
Author(s):  
Horacio J. Novaira ◽  
Ariel L. Negron ◽  
Jones B. Graceli ◽  
Silvia Capellino ◽  
Andrew Schoeffield ◽  
...  
Keyword(s):  
Mouse Models ◽  
Reproductive Function ◽  
Stimulation Test ◽  
Abnormal Development ◽  
Gnrh Neuron ◽  
Serum Luteinizing Hormone ◽  
Reproductive Axis ◽  
Gnrh Neurons ◽  
Serum Gonadotropin

The effect of estrogen on the differentiation and maintenance of reproductive tissues is mediated by two nuclear estrogen receptors (ERs), ERα, and ERβ. Lack of functional ERα and ERβ genes in vivo significantly affects reproductive function; however, the target tissues and signaling pathways in the hypothalamus are not clearly defined. Here, we describe the generation and reproductive characterization of a complete-ERβ KO (CERβKO) and a GnRH neuron-specific ERβKO (GERβKO) mouse models. Both ERβKO mouse models displayed a delay in vaginal opening and first estrus. Hypothalamic gonadotropin-releasing hormone (GnRH) mRNA expression levels in both ERβKO mice were similar to control mice; however female CERβKO and GERβKO mice had lower basal and surge serum gonadotropin levels. Although a GnRH stimulation test in both female ERβKO models showed preserved gonadotropic function in the same animals, a kisspeptin stimulation test revealed an attenuated response by GnRH neurons, suggesting a role for ERβ in normal GnRH neuron function. No alteration in estrogen-negative feedback was observed in either ERβKO mouse models after ovariectomy and estrogen replacement. Further, abnormal development of ovarian follicles with low serum estradiol levels and impairment of fertility were observed in both ERβKO mouse models. In male ERβKO mice, no differences in the timing of pubertal onset or serum luteinizing hormone and follicle-stimulating hormone levels were observed as compared with controls. Taken together, these data provide in vivo evidence for a role of ERβ in GnRH neurons in modulating puberty and reproduction, specifically through kisspeptin responsiveness in the female hypothalamic-pituitary-gonadal axis.

scholarly journals Chronic Excess of Non-Aromatizable Androgens From Puberty Does Not Drive a Neuroendocrine Phenotype Observed in Other Preclinical Rodent Models of PCOS

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A533-A534
Author(s):  
Chris Coyle ◽  
Amy Ruddenklau ◽  
Mel Prescott ◽  
Kirsty A Walters ◽  
Rebecca Elaine Campbell
Keyword(s):  
Chronic Exposure ◽  
Fluorescent Protein ◽  
Polycystic Ovary ◽  
Prenatal Development ◽  
Reproductive Age ◽  
Androgen Excess ◽  
Gabaergic Innervation ◽  
Lh Pulsatility ◽  
Gnrh Neurons ◽  
The Brain

Abstract Polycystic ovary syndrome (PCOS) is the most common form of anovulatory infertility in women of reproductive age, characterised by androgen excess, polycystic appearance of the ovary and irregular menstruation. PCOS is also frequently associated with metabolic abnormalities, including increased adiposity and insulin resistance. The origins of PCOS are unknown, however recent findings in animal models strongly implicate androgen signalling in the brain in the development of PCOS pathophysiology. Exposure to androgen excess, either acutely during prenatal development or chronically from a peripubertal timepoint, can drive the development of PCOS-like features in adulthood. Prenatally androgenized (PNA) mice exhibit the cardinal reproductive features of PCOS and increased luteinizing hormone (LH) pulse frequency. This phenotype is associated with increased GABAergic innervation of gonadotropin-releasing hormone (GnRH) neurons, postulated to drive elevated GnRH/LH release and downstream effects. Chronic exposure to di-hydrotestosterone (DHT) from 3 weeks of age drives both reproductive and metabolic PCOS-like features that are ameliorated by selective AR loss from the brain. Here, we aimed to determine whether chronic exposure to DHT drives a similar increase in LH pulsatility and elevated GABAergic innervation to GnRH neurons as seen following prenatal exposure to androgen excess. GnRH-green fluorescent protein (GFP) female mice received either DHT or blank capsules for 90 days from postnatal day (PND) 21 (N = 6-7/group). Serial tail tip blood sampling was used to measure pulsatile LH and fixed brains were collected and immunolabelled for vesicular GABA transporter (VGAT) to assess putative GABAergic terminals associated with GFP-labelled GnRH neurons. Chronic androgen excess from the peripubertal period resulted in acyclicity and increased body weight as expected. However, LH pulsatility was not different between DHT-treated females and controls. Similarly, the density of VGAT appositions to GnRH neurons was not different between groups. Therefore, the programmed changes in the GnRH neuronal network and hyperactive LH secretion that result from prenatal androgen excess are not affected by chronic DHT exposure initiated at 3 weeks of age. These findings suggest that unique central mechanisms are involved in the reproductive impairments driven by exposure to androgen excess at different developmental stages.

scholarly journals Developmental programming: prenatal androgen excess disrupts ovarian steroid receptor balance

Reproduction ◽  
2009 ◽  
Vol 137 (5) ◽  
pp. 865-877 ◽  
Author(s):  
Hugo H Ortega ◽  
Natalia R Salvetti ◽  
Vasantha Padmanabhan
Keyword(s):  
Protein Expression ◽  
Granulosa Cells ◽  
Steroid Receptor ◽  
Developmental Trajectory ◽  
Receptor Expression ◽  
Model Systems ◽  
Receptor Protein ◽  
Androgen Excess ◽  
Ovarian Steroid ◽  
Prenatal Androgen

Steroid hormones play an important role in reproduction and the receptors through which they signal change in a developmental time, follicle stage, and cell-specific manner. Disruption in steroid receptor expression affects follicle formation and differentiation. In this study, using prenatal testosterone (T) and dihydrotestosterone (DHT)-treated female sheep as model systems, we tested the hypothesis that prenatal androgen excess disrupts the developmental ontogeny of ovarian steroid receptor protein expression. Pregnant Suffolk ewes were injected twice weekly with T propionate or DHT propionate (a non-aromatizable androgen) in cottonseed oil from days 30 to 90 of gestation. Changes in ovarian estrogen receptors (ER; ESR1, ESR2), androgen receptor (AR) and progesterone receptor (PGR) proteins were determined at fetal (days 90 and 140), postpubertal (10 months), and adult (21 months; only prenatal T-treated sheep studied) ages by immunohistochemistry. Prenatal T and DHT treatment induced selective increase in AR but not ER or PGR expression in the stroma and granulosa cells of fetal days 90 and 140 ovaries. An increase in ESR1 and decrease in ESR2 immunostaining coupled with increased AR expression were evident in granulosa cells of antral follicles of 10- and 21-month-old prenatal T but not DHT-treated females (analyzed only at 10 months). These findings provide evidence that an early increase in ovarian AR is the first step in the altered ovarian developmental trajectory of prenatal T-treated females, and manifestations of postnatal ovarian dysfunction are likely facilitated via altered equilibrium of antral follicular granulosa cell ER/AR protein expression.

scholarly journals Prenatal androgen excess enhances stimulation of the GNRH pulse in pubertal female rats

2014 ◽  
Vol 222 (1) ◽  
pp. 73-85 ◽  
Author(s):  
Xiaonan Yan ◽  
Chun Yuan ◽  
Nannan Zhao ◽  
Yugui Cui ◽  
Jiayin Liu
Keyword(s):  
Polycystic Ovary ◽  
Elevated Serum ◽  
Pulse Frequency ◽  
Female Rats ◽  
Mrna Levels ◽  
Pregnant Rats ◽  
Serum Lh ◽  
Gnrh Neurons ◽  
Prenatal Androgen ◽  
Stimulation Of

In adolescent girls with polycystic ovary syndrome (PCOS), neuroendocrine derangements manifest after the onset of puberty, characterized by rapid LH pulse frequency. The early mechanism underlying the pubertal regulation of the GNRH/LH pulsatile release in adolescents with PCOS remains uncertain. To determine the effects of prenatal androgen exposure on the activation of GNRH neurons and generation of LH pulse at puberty, we administrated 5α-dihydrotestosterone to pregnant rats and observed serum LH levels and expression of hypothalamic genes in female offspring from postnatal 4 to 8 weeks. The 6-week-old prenatally androgenized (PNA) female rats exhibited an increase in LH pulse frequency. The hypothalamic expression of neurokinin B (Nkb(Tac2)) andLeprmRNA levels in PNA rats increased remarkably before puberty and remained high during puberty, whereas elevatedKiss1mRNA levels were detected only after the onset of puberty. Exogenous kisspeptin, NK3R agonist, and leptin triggered tonic stimulation of GNRH neurons and increased LH secretion in 6-week-old PNA rats. Leptin upregulatedKiss1mRNA levels in the hypothalamus of pubertal PNA rats; however, pretreatment with a kisspeptin antagonist failed to suppress the elevated serum LH stimulated by leptin, indicating that the stimulatory effects of leptin may be conveyed indirectly to GNRH neurons via other neural components within the GNRH neuronal network, rather than through the kisspeptin–GPR54 pathway. These findings validate the hypotheses that NKB and leptin play an essential role in the activation of GNRH neurons and initiation of increased LH pulse frequency in PNA female rats at puberty and that kisspeptin may coordinate their stimulatory effects on LH release.

scholarly journals Fetal androgen exposure is a determinant of adult male metabolic health

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Katarzyna J. Siemienowicz ◽  
Panagiotis Filis ◽  
Sophie Shaw ◽  
Alex Douglas ◽  
Jennifer Thomas ◽  
...  
Keyword(s):  
Adult Male ◽  
Polycystic Ovary ◽  
Metabolic Health ◽  
Androgen Excess ◽  
Male Health ◽  
Androgen Exposure ◽  
Gene And Protein Expression ◽  
Clinical Conditions ◽  
Prenatal Androgen ◽  
Stress Gene

AbstractAndrogen signalling is a critical driver of male development. Fetal steroid signalling can be dysregulated by a range of environmental insults and clinical conditions. We hypothesised that poor adult male health was partially attributable to aberrant androgen exposure during development. Testosterone was directly administered to developing male ovine fetuses to model excess prenatal androgenic overexposure associated with conditions such as polycystic ovary syndrome (PCOS). Such in utero androgen excess recreated the dyslipidaemia and hormonal profile observed in sons of PCOS patients. 1,084 of 15,134 and 408 of 2,766 quantifiable genes and proteins respectively, were altered in the liver during adolescence, attributable to fetal androgen excess. Furthermore, prenatal androgen excess predisposed to adolescent development of an intrahepatic cholestasis-like condition with attendant hypercholesterolaemia and an emergent pro-fibrotic, pro-oxidative stress gene and protein expression profile evident in both liver and circulation. We conclude that prenatal androgen excess is a previously unrecognised determinant of lifelong male metabolic health.

scholarly journals Prenatal Androgenization of Female Mice Programs an Increase in Firing Activity of Gonadotropin-Releasing Hormone (GnRH) Neurons That Is Reversed by Metformin Treatment in Adulthood

Endocrinology ◽  
2010 ◽  
Vol 152 (2) ◽  
pp. 618-628 ◽  
Author(s):  
Alison V. Roland ◽  
Suzanne M. Moenter
Keyword(s):  
Polycystic Ovary ◽  
Neuron Activity ◽  
Metformin Treatment ◽  
Ampk Activation ◽  
Gnrh Neuron ◽  
Firing Activity ◽  
Ovary Syndrome ◽  
Estrous Cycles ◽  
Compound C ◽  
Gnrh Neurons

Abstract Prenatal androgenization (PNA) of female mice with dihydrotestosterone programs reproductive dysfunction in adulthood, characterized by elevated luteinizing hormone levels, irregular estrous cycles, and central abnormalities. Here, we evaluated activity of GnRH neurons from PNA mice and the effects of in vivo treatment with metformin, an activator of AMP-activated protein kinase (AMPK) that is commonly used to treat the fertility disorder polycystic ovary syndrome. Estrous cycles were monitored in PNA and control mice before and after metformin administration. Before metformin, cycles were longer in PNA mice and percent time in estrus lower; metformin normalized cycles in PNA mice. Extracellular recordings were used to monitor GnRH neuron firing activity in brain slices from diestrous mice. Firing rate was higher and quiescence lower in GnRH neurons from PNA mice, demonstrating increased GnRH neuron activity. Metformin treatment of PNA mice restored firing activity and LH to control levels. To assess whether AMPK activation contributed to the metformin-induced reduction in GnRH neuron activity, the AMPK antagonist compound C was acutely applied to cells. Compound C stimulated cells from metformin-treated, but not untreated, mice, suggesting that AMPK was activated in GnRH neurons, or afferent neurons, in the former group. GnRH neurons from metformin-treated mice also showed a reduced inhibitory response to low glucose. These studies indicate that PNA causes enhanced firing activity of GnRH neurons and elevated LH that are reversible by metformin, raising the possibility that central AMPK activation by metformin may play a role in its restoration of reproductive cycles in polycystic ovary syndrome.

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