RESUMEN
In late 2003, a major breakthrough in our understanding of the mechanisms that govern reproduction occurred with the identification of the reproductive roles of kisspeptins, encoded by the Kiss1 gene, and their receptor, Gpr54 (aka, Kiss1R). The discovery of this unsuspected reproductive facet attracted an extraordinary interest and boosted an intense research activity, in human and model species, that, in a relatively short period, established a series of basic concepts on the physiological roles of kisspeptins. Such fundamental knowledge, gathered in these early years of kisspeptin research, set the scene for the more recent in-depth dissection of the intimacies of the neuronal networks involving Kiss1 neurons, their precise mechanisms of regulation and the molecular underpinnings of the function of kisspeptins as pivotal regulators of all key aspects of reproductive function, from puberty onset to pulsatile gonadotropin secretion and the metabolic control of fertility. While no clear temporal boundaries between these two periods can be defined, in this review we will summarize the most prominent advances in kisspeptin research occurred in the last ten years, as a means to provide an up-dated view of the state of the art and potential paths of future progress in this dynamic, and ever growing domain of Neuroendocrinology.
Asunto(s)
Kisspeptinas , Reproducción , Hormona Liberadora de Gonadotropina/metabolismo , Humanos , Kisspeptinas/metabolismo , Sistemas Neurosecretores/metabolismo , Pubertad/metabolismo , Receptores Acoplados a Proteínas G , Receptores de Kisspeptina-1/metabolismo , Reproducción/fisiologíaRESUMEN
Autonomic innervation is important to regulate homeostasis in every organ of the body. The sympathetic nervous system controls several organs associated with metabolism and reproduction, including adipose tissue, the liver, and the ovaries. The sympathetic nervous system is controlled within the central nervous system by neurons located in the hypothalamus, which in turn are regulated by hormones like leptin. Leptin action in the hypothalamus leads to increased sympathetic activity in the adipose tissue. In this short report, we propose that leptin action in the brain also controls the sympathetic innervation of other organs like the liver and the ovary. We performed two experiments: We performed an intracerebroventricular (ICV) injection of leptin and measured norepinephrine levels in several organs, and we used a validated model of overnutrition and obesity to evaluate whether an increase in leptin levels coexists with high levels of norepinephrine in the liver and ovaries. Norepinephrine was measured by ELISA in adipose tissue and by HPLC-EC in other tissues. Leptin was measured by ELISA. We found that the ICV injection of leptin increases norepinephrine levels in several organs, including the liver and ovaries. Also, we found that diet-induced obesity leads to an increase in leptin levels while inducing an increase in norepinephrine levels in the liver and ovaries. Finally, since hyperactivity of the sympathetic nervous system is observed both in non-alcoholic fatty liver disease and polycystic ovary syndrome, we think that an increase in norepinephrine levels induced by hyperleptinemia could be involved in the pathogenesis of both diseases.
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Leptina , Norepinefrina , Femenino , Tejido Adiposo/metabolismo , Dieta , Leptina/metabolismo , Norepinefrina/metabolismo , Obesidad/metabolismo , Sistema Nervioso Simpático , Animales , RatasRESUMEN
BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare malignancy, classified according to the Peritoneal Surface Oncology Group International (PSOGI) classification, whose response to treatment remains highly heterogeneous within the high-grade (HG) category. Molecular profiling of PMP cases might help to better categorize patients and predict treatment responses. METHODS: We studied the Ki-67 proliferation rate and P53 overexpression in tissue samples from our historical cohort of HG-PMP patients. We established as cut-off levels the third quartile of each marker to perform univariate and multivariate Cox regression survival analyses. According to these results, the HG-PMP category was divided into subcategories and a new survival analysis was performed. RESULTS: A total of 90/117 patients with PMP undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) were selected for secondary analysis. The survival analysis of the HG-PMP category for preoperative variables showed that a proliferation index defined by Ki-67 >15% is a bad prognostic factor, with a hazard ratio (HR) of 3.20 (95% confidence interval [CI] 1.24-8.25). Accordingly, the HG-PMP group was divided using the Ki-67 15% cut-off. The new PSOGI/Ki-67 variable was an independent prognostic factor for overall survival (OS), with an HR of 3.74 (95% CI 1.88-7.47), and disease-free survival (DFS), with an HR of 4.184 (95% CI 1.79-9.75). The estimated 5-year OS rate was 100%, 70% and 24% for the LG-PMP, HG-PMP ≤15% and HG-PMP >15% groups, respectively (p = 0.0001), while the 5-year DFS rate was 90%, 44% and 0%, respectively (p = 0.0001). CONCLUSION: Division of the HG-PMP category of the PSOGI classification, according to the Ki-67 proliferation index, provides two well-defined subcategories, with significant differences in terms of OS and DFS, and hence high prognostic value.
Asunto(s)
Neoplasias Peritoneales , Seudomixoma Peritoneal , Proliferación Celular , Humanos , Antígeno Ki-67 , Neoplasias Peritoneales/terapia , Seudomixoma Peritoneal/terapiaRESUMEN
STUDY QUESTION: Does direct kisspeptin signaling in the oocyte have a role in the control of follicular dynamics and ovulation? SUMMARY ANSWER: Kisspeptin signaling in the oocyte plays a relevant physiological role in the direct control of ovulation; oocyte-specific ablation of kisspeptin receptor, Gpr54, induces a state of premature ovulatory failure in mice that recapitulates some features of premature ovarian insufficiency (POI). WHAT IS KNOWN ALREADY: Kisspeptins, encoded by the Kiss1 gene, are essential for the control of ovulation and fertility, acting primarily on hypothalamic GnRH neurons to stimulate gonadotropin secretion. However, kisspeptins and their receptor, Gpr54, are also expressed in the ovary of different mammalian species, including humans, where their physiological roles remain contentious and poorly characterized. STUDY DESIGN, SIZE, DURATION: A novel mouse line with conditional ablation of Gpr54 in oocytes, named OoGpr54-/-, was generated and studied in terms of follicular and ovulatory dynamics at different age-points of postnatal maturation. A total of 59 OoGpr54-/- mice and 47 corresponding controls were analyzed. In addition, direct RNA sequencing was applied to ovarian samples from 8 OoGpr54-/- and 7 control mice at 6 months of age, and gonadotropin priming for ovulatory induction was conducted in mice (N = 7) from both genotypes. PARTICIPANTS/MATERIALS, SETTING, METHODS: Oocyte-selective ablation of Gpr54 in the oocyte was achieved in vivo by crossing a Gdf9-driven Cre-expressing transgenic mouse line with a Gpr54 LoxP mouse line. The resulting OoGpr54-/- mouse line was subjected to phenotypic, histological, hormonal and molecular analyses at different age-points of postnatal maturation (Day 45, and 2, 4, 6 and 10-11 months of age), in order to characterize the timing of puberty, ovarian follicular dynamics and ovulation, with particular attention to identification of features reminiscent of POI. The molecular signature of ovaries from OoGpr54-/- mice was defined by direct RNA sequencing. Ovulatory responses to gonadotropin priming were also assessed in OoGpr54-/- mice. MAIN RESULTS AND THE ROLE OF CHANCE: Oocyte-specific ablation of Gpr54 caused premature ovulatory failure, with some POI-like features. OoGpr54-/- mice had preserved puberty onset, without signs of hypogonadism. However, already at 2 months of age, 40% of OoGpr54-/- females showed histological features reminiscent of ovarian failure and anovulation. Penetrance of the phenotype progressed with age, with >80% and 100% of OoGpr54-/- females displaying complete ovulatory failure by 6- and 10 months, respectively. This occurred despite unaltered hypothalamic Gpr54 expression and gonadotropin levels. Yet, OoGpr54-/- mice had decreased sex steroid levels. While the RNA signature of OoGpr54-/- ovaries was dominated by the anovulatory state, oocyte-specific ablation of Gpr54 significantly up- or downregulated of a set of 21 genes, including those encoding pituitary adenylate cyclase-activating polypeptide, Wnt-10B, matrix-metalloprotease-12, vitamin A-related factors and calcium-activated chloride channel-2, which might contribute to the POI-like state. Notably, the anovulatory state of young OoGpr54-/- mice could be rescued by gonadotropin priming. LARGE SCALE DATA: N/A. . LIMITATIONS, REASONS FOR CAUTION: Conditional ablation of Gpr54 in oocytes unambiguously caused premature ovulatory failure in mice; yet, the ultimate molecular mechanisms for such state of POI can be only inferred on the basis of RNAseq data and need further elucidation, since some of the molecular changes observed in OoGpr54-/- ovaries were secondary to the anovulatory state. Direct translation of mouse findings to human disease should be made with caution since, despite the conserved expression of Kiss1/kisspeptin and Gpr54 in rodents and humans, our mouse model does not recapitulate all features of common forms of POI. WIDER IMPLICATIONS OF THE FINDINGS: Deregulation of kisspeptin signaling in the oocyte might be an underlying, and previously unnoticed, cause for some forms of POI in women. STUDY FUNDING/COMPETING INTEREST(S): This work was primarily supported by a grant to M.P. and M.T.-S. from the FiDiPro (Finnish Distinguished Professor) Program of the Academy of Finland. Additional financial support came from grant BFU2017-83934-P (M.T.-S.; Ministerio de Economía y Competitividad, Spain; co-funded with EU funds/FEDER Program), research funds from the IVIRMA International Award in Reproductive Medicine (M.T.-S.), and EFSD Albert Renold Fellowship Programme (S.T.R.). The authors have no conflicts of interest to declare in relation to the contents of this work. TRIAL REGISTRATION NUMBER: N/A.
Asunto(s)
Anovulación , Kisspeptinas , Animales , Femenino , Humanos , Kisspeptinas/genética , Mamíferos/metabolismo , Ratones , Oocitos/metabolismo , OvulaciónRESUMEN
Mkrn3, the maternally imprinted gene encoding the makorin RING-finger protein-3, has recently emerged as putative pubertal repressor, as evidenced by central precocity caused by MKRN3 mutations in humans; yet, the molecular underpinnings of this key regulatory action remain largely unexplored. We report herein that the microRNA, miR-30, with three binding sites in a highly conserved region of its 3' UTR, operates as repressor of Mkrn3 to control pubertal onset. Hypothalamic miR-30b expression increased, while Mkrn3 mRNA and protein content decreased, during rat postnatal maturation. Neonatal estrogen exposure, causing pubertal alterations, enhanced hypothalamic Mkrn3 and suppressed miR-30b expression in female rats. Functional in vitro analyses demonstrated a strong repressive action of miR-30b on Mkrn3 3' UTR. Moreover, central infusion during the juvenile period of target site blockers, tailored to prevent miR-30 binding to Mkrn3 3' UTR, reversed the prepubertal down-regulation of hypothalamic Mkrn3 protein and delayed female puberty. Collectively, our data unveil a novel hypothalamic miRNA pathway, involving miR-30, with a prominent role in the control of puberty via Mkrn3 repression. These findings expand our current understanding of the molecular basis of puberty and its disease states.
Asunto(s)
Hipotálamo/metabolismo , MicroARNs/fisiología , Maduración Sexual/genética , Ubiquitina-Proteína Ligasas/genética , Animales , Sitios de Unión , Línea Celular , Femenino , Regulación del Desarrollo de la Expresión Génica , Masculino , MicroARNs/metabolismo , Ratas , Análisis de Secuencia de ADNRESUMEN
Weight gain is a hallmark of decreased estradiol (E2) levels because of menopause or following surgical ovariectomy (OVX) at younger ages. Of note, this weight gain tends to be around the abdomen, which is frequently associated with impaired metabolic homeostasis and greater cardiovascular risk in both rodents and humans. However, the molecular underpinnings and the neuronal basis for these effects remain to be elucidated. The aim of this study is to elucidate whether the kappa-opioid receptor (k-OR) system is involved in mediating body weight changes associated with E2 withdrawal. Here, we document that body weight gain induced by OVX occurs, at least partially, in a k-OR dependent manner, by modulation of energy expenditure independently of food intake as assessed in Oprk1-/-global KO mice. These effects were also observed following central pharmacological blockade of the k-OR system using the k-OR-selective antagonist PF-04455242 in wild type mice, in which we also observed a decrease in OVX-induced weight gain associated with increased UCP1 positive immunostaining in brown adipose tissue (BAT) and browning of white adipose tissue (WAT). Remarkably, the hypothalamic mTOR pathway plays an important role in regulating weight gain and adiposity in OVX mice. These findings will help to define new therapies to manage metabolic disorders associated with low/null E2 levels based on the modulation of central k-OR signaling.
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Ingestión de Alimentos , Receptores Opioides kappa , Tejido Adiposo Pardo/metabolismo , Animales , Peso Corporal , Metabolismo Energético , Estrógenos/metabolismo , Femenino , Humanos , Ratones , Obesidad/tratamiento farmacológico , Obesidad/etiología , Obesidad/metabolismo , Ovariectomía/efectos adversos , Receptores Opioides kappa/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Aumento de PesoRESUMEN
Tachykinin (TAC) signaling is an important element in the central control of reproduction. TAC family is mainly composed of substance P (SP), neurokinin A (NKA), and NKB, which bind preferentially to NK1, NK2, and NK3 receptors, respectively. While most studies have focused on the reproductive functions of NKB/NK3R, and to a lesser extent SP/NK1R, the relevance of NK2R, encoded by Tacr2, remains poorly characterized. Here, we address the physiological roles of NK2R in regulating the reproductive axis by characterizing a novel mouse line with congenital ablation of Tacr2. Activation of NK2R evoked acute luteinizing hormone (LH) responses in control mice, similar to those of agonists of NK1R and NK3R. Despite the absence of NK2R, Tacr2-/- mice displayed only partially reduced LH responses to an NK2R agonist, which, nonetheless, were abrogated after blockade of NK3R in Tacr2-/- males. While Tacr2-/- mice displayed normal pubertal timing, LH pulsatility was partially altered in Tacr2-/- females in adulthood, with suppression of basal LH levels, but no changes in the number of LH pulses. In addition, trends for increase in breeding intervals were detected in Tacr2-/- mice. However, null animals of both sexes were fertile, with no changes in estrous cyclicity or sex preference in social behavioral tests. In conclusion, stimulation of NK2R elicited LH responses in mice, while congenital ablation of Tacr2 partially suppressed basal and stimulated LH secretion, with moderate reproductive impact. Our data support a modest, albeit detectable, role of NK2R in the control of the gonadotropic axis, with partially overlapping and redundant functions with other tachykinin receptors.NEW & NOTEWORTHY We have explored here the impact of congenital ablation of the gene (Tacr2) encoding the tachykinin receptor, NK2R, in terms of neuroendocrine control of the reproductive axis, using a novel Tacr2 KO mouse line. Our data support a modest, albeit detectable, role of NK2R in the control of the gonadotropic axis, with partially overlapping and redundant functions with other tachykinin receptors.
Asunto(s)
Receptores de Neuroquinina-2/genética , Reproducción/genética , Animales , Femenino , Hormonas Esteroides Gonadales/metabolismo , Hipotálamo/metabolismo , Hormona Luteinizante/sangre , Masculino , Ratones , Ratones Noqueados , Ratones Obesos , Embarazo , Efectos Tardíos de la Exposición Prenatal/genética , Efectos Tardíos de la Exposición Prenatal/fisiopatología , Receptores de Neuroquinina-2/deficiencia , Reproducción/fisiología , Transducción de Señal/genética , TranscriptomaRESUMEN
Conditions of metabolic distress, from malnutrition to obesity, impact, via as yet ill-defined mechanisms, the timing of puberty, whose alterations can hamper later cardiometabolic health and even life expectancy. AMP-activated protein kinase (AMPK), the master cellular energy sensor activated in conditions of energy insufficiency, has a major central role in whole-body energy homeostasis. However, whether brain AMPK metabolically modulates puberty onset remains unknown. We report here that central AMPK interplays with the puberty-activating gene, Kiss1, to control puberty onset. Pubertal subnutrition, which delayed puberty, enhanced hypothalamic pAMPK levels, while activation of brain AMPK in immature female rats substantially deferred puberty. Virogenetic overexpression of a constitutively active form of AMPK, selectively in the hypothalamic arcuate nucleus (ARC), which holds a key population of Kiss1 neurons, partially delayed puberty onset and reduced luteinizing hormone levels. ARC Kiss1 neurons were found to express pAMPK, and activation of AMPK reduced ARC Kiss1 expression. The physiological relevance of this pathway was attested by conditional ablation of the AMPKα1 subunit in Kiss1 cells, which largely prevented the delay in puberty onset caused by chronic subnutrition. Our data demonstrate that hypothalamic AMPK signaling plays a key role in the metabolic control of puberty, acting via a repressive modulation of ARC Kiss1 neurons in conditions of negative energy balance.
Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Núcleo Arqueado del Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Desnutrición/metabolismo , Neuronas/metabolismo , Maduración Sexual/genética , Proteínas Quinasas Activadas por AMP/genética , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacología , Animales , Animales Modificados Genéticamente , Núcleo Arqueado del Hipotálamo/citología , Núcleo Arqueado del Hipotálamo/efectos de los fármacos , Restricción Calórica/efectos adversos , Estradiol/farmacología , Femenino , Regulación del Desarrollo de la Expresión Génica , Kisspeptinas/genética , Hormona Luteinizante/sangre , Desnutrición/genética , Desnutrición/fisiopatología , Ratones , Ratones Endogámicos C57BL , Neuronas/citología , Neuronas/efectos de los fármacos , Ratas , Ratas Wistar , Ribonucleótidos/farmacología , Transducción de Señal , Factores de TiempoRESUMEN
Hepatic fat-specific protein 27 [cell death-inducing DNA fragmentation effector protein C (Cidec)/Fsp27] mRNA levels have been associated with hepatic lipid droplet extent under certain circumstances. To address its hepatic expression under different dietary conditions and in both sexes, apolipoprotein E (Apoe)-deficient mice were subjected to different experimental conditions for 11 wk to test the influence of cholesterol, Western diet, squalene, oleanolic acid, sex, and surgical castration on Cidec/Fsp27 mRNA expression. Dietary cholesterol increased hepatic Cidec/Fsp27ß expression, an effect that was suppressed when cholesterol was combined with saturated fat as represented by Western diet feeding. Using the latter diet, neither oleanolic acid nor squalene modified its expression. Females showed lower levels of hepatic Cidec/Fsp27ß expression than males when they were fed Western diets, a result that was translated into a lesser amount of CIDEC/FSP27 protein in lipid droplets and microsomes. This was also confirmed in low-density lipoprotein receptor (Ldlr)-deficient mice. Incubation with estradiol resulted in decreased Cidec/Fsp27ß expression in AML12 cells. Whereas male surgical castration did not modify the expression, ovariectomized females did show increased levels compared with control females. Females also showed increased expression of peroxisome proliferator-activated receptor-γ coactivator 1-α (Pgc1a), suppressed by ovariectomy, and the values were significantly and inversely associated with those of Cidec/Fsp27ß. When Pgc1a-deficient mice were used, the sex differences in Cidec/Fsp27ß expression disappeared. Therefore, hepatic Cidec/Fsp27ß expression has a complex regulation influenced by diet and sex hormonal milieu. The mRNA sex differences are controlled by Pgc1a.
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Dieta Occidental/efectos adversos , Hígado/metabolismo , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Proteínas/genética , Animales , Línea Celular , Colesterol en la Dieta/farmacología , Femenino , Gotas Lipídicas/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/genética , Orquiectomía , Ovariectomía , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , ARN Mensajero/biosíntesis , Receptores de LDL/genética , Receptores de LDL/metabolismo , Caracteres SexualesRESUMEN
Energy metabolism and reproduction are closely linked and reciprocally regulated. The detrimental effect of underweight on reproduction complicates the safety evaluation of anti-obesity drugs, making it challenging to distinguish pathological changes mediated through the intended drug-induced weight loss from direct drug effects on reproductive organs. Four-weeks dosing of normal weight Sprague Dawley rats with a glucagon-like peptide 1 (GLP-1)/glucagon receptor co-agonist induced a robust weight loss, accompanied by histological findings in prostate, seminal vesicles, mammary glands, uterus/cervix and vagina. Characterization of the hypothalamus-pituitary-gonadal (HPG) axis in male rats revealed reduced hypothalamic Kiss1 mRNA levels and decreased serum luteinizing hormone (LH) and testosterone concentrations following co-agonist dosing. These alterations resemble hypogonadotropic hypogonadism typically seen in adverse energy deprived conditions, like chronic food restriction. Concomitant daily administration of kisspeptin-52 from day 21 to the end of the four-week co-agonist dosing period evoked LH and testosterone responses without normalizing histological findings. This incomplete rescue by kisspeptin-52 may be due to the rather short kisspeptin-52 treatment period combined with a desensitization observed on testosterone responses. Concomitant leptin treatment from day 21 did not reverse co-agonist induced changes in HPG axis activity. Furthermore, a single co-agonist injection in male rats slightly elevated LH levels but left testosterone unperturbed, thereby excluding a direct acute inhibitory effect on the HPG axis. Our data suggest that the reproductive phenotype after repeated co-agonist administration was driven by the intended weight loss, however, we cannot exclude a direct organ related effect in chronically treated rats.
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Fármacos Antiobesidad/farmacología , Sistema Hipotálamo-Hipofisario/efectos de los fármacos , Kisspeptinas/farmacología , Testículo/efectos de los fármacos , Animales , Kisspeptinas/administración & dosificación , Masculino , Ratas , Ratas Sprague-Dawley , Testículo/metabolismo , Delgadez , Pérdida de Peso/efectos de los fármacosRESUMEN
Procreation is essential for survival of species. Not surprisingly, complex neuronal networks have evolved to mediate the diverse internal and external environmental inputs that regulate reproduction in vertebrates. Ultimately, these regulatory factors impinge, directly or indirectly, on a final common pathway, the neurons producing the gonadotropin-releasing hormone (GnRH), which stimulates pituitary gonadotropin secretion and thereby gonadal function. Compelling evidence, accumulated in the last few years, has revealed that kisspeptins, a family of neuropeptides encoded by the Kiss1 gene and produced mainly by neuronal clusters at discrete hypothalamic nuclei, are pivotal upstream regulators of GnRH neurons. As such, kisspeptins have emerged as important gatekeepers of key aspects of reproductive maturation and function, from sexual differentiation of the brain and puberty onset to adult regulation of gonadotropin secretion and the metabolic control of fertility. This review aims to provide a comprehensive account of the state-of-the-art in the field of kisspeptin physiology by covering in-depth the consensus knowledge on the major molecular features, biological effects, and mechanisms of action of kisspeptins in mammals and, to a lesser extent, in nonmammalian vertebrates. This review will also address unsolved and contentious issues to set the scene for future research challenges in the area. By doing so, we aim to endow the reader with a critical and updated view of the physiological roles and potential translational relevance of kisspeptins in the integral control of reproductive function.
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Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Reproducción , Transducción de Señal , Animales , Dinorfinas/metabolismo , Retroalimentación Fisiológica , Femenino , Hormona Liberadora de Gonadotropina/metabolismo , Gonadotropinas/metabolismo , Humanos , Masculino , Vías Nerviosas/metabolismo , Neuroquinina B/metabolismo , Pubertad/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Neuropéptido/metabolismo , Diferenciación SexualRESUMEN
Acquisition of reproductive maturity involves one of the most important series of developmental events in an organism's life. The beginning of adolescence is marked by the onset of puberty. Puberty is the continuum of physical changes through which an infantile body matures into an adult capable of reproduction. This is a period of increased brain plasticity, where processes of re-wiring, neuronal proliferation, and pruning are enhanced. The initiation of mammalian puberty requires an increased pulsatile release of gonadotropin-releasing hormone from the hypothalamus. Puberty is regulated by neuroendocrine, genetic, and epigenetic factors. The maturation and function of the reproductive axis are highly sensitive to the energy status of the organism and sophisticated mechanisms exist to inhibit the axis in unfavorable energetic or metabolic conditions.In this review, we will focus on the impact of alcohol and obesity on reproductive outcomes, with emphasis on their effects on the timing of puberty. In the case of obesity, conflictive data are found, and while in females the association of overnutrition with advanced onset of puberty is consistent, in males, discrepant results have been reported. Concerning alcohol exposure, compelling evidence has documented a delay in the onset of puberty. We will present here data from both clinical studies and research involving preclinical models, which do not only delineate the impact of these conditions on the timing of puberty and potential underlying mechanisms, but that may help to define better strategies for the rational management of puberty disorders, especially of metabolic origin.
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Consumo de Bebidas Alcohólicas/fisiopatología , Etanol/farmacología , Obesidad Infantil/fisiopatología , Pubertad/efectos de los fármacos , Maduración Sexual/efectos de los fármacos , Adolescente , Adulto , Edad de Inicio , Animales , Femenino , Humanos , Masculino , Obesidad Infantil/complicaciones , Pubertad/fisiología , Maduración Sexual/fisiología , Factores de TiempoRESUMEN
BACKGROUND: Ectopic pregnancy is a life-threatening condition for which novel screening tools that would enable early accurate diagnosis would improve clinical outcomes. Kisspeptins, encoded by KISS1, play an essential role in human reproduction, at least partially by regulating placental function and possibly embryo implantation. Kisspeptin levels are elevated massively in normal pregnancy and reportedly altered in various gestational pathologic diseases. Yet, the pathophysiologic role of KISS1/kisspeptin in ectopic pregnancy has not been investigated previously. OBJECTIVE: The purpose of this study was to evaluate changes of KISS1/kisspeptin levels in ectopic pregnancy and their underlaying molecular mechanisms and to ascertain the diagnostic implications of these changes. STUDY DESIGN: A total of 122 women with normal pregnancy who underwent voluntary termination of pregnancy and 84 patients who experienced tubal ectopic pregnancy were recruited. Measurements of plasma kisspeptins and KISS1 expression analyses in human embryonic/placental tissue were conducted in ectopic pregnancy and voluntary termination of pregnancy control subjects during the early gestational window (<12 weeks). Putative microRNA regulators of KISS1 were predicted in silico, followed by expression analyses of selected microRNAs and validation of repressive interactions in vitro. Circulating levels of these microRNAs were also assayed in ectopic pregnancy vs voluntary termination of pregnancy. RESULTS: Circulating kisspeptins gradually increased during the first trimester of normal pregnancy but were reduced markedly in ectopic pregnancy. This profile correlated with the expression levels of KISS1 in human embryonic/placental tissue, which increased in voluntary termination of pregnancy but remained suppressed in ectopic pregnancy. Bioinformatic predictions and expression analyses identified miR-27b-3p and miR-324-3p as putative repressors of KISS1 in human embryonic/placental tissue at <12 weeks gestation, when expression of microRNAs was low in voluntary termination of pregnancy control subjects but significantly increased in ectopic pregnancy. Yet, a significant repressive interaction was documented only for miR-324-3p, occurring at the predicted 3'-UTR of KISS1. Interestingly, circulating levels of miR-324-3p, but not of miR-27b-3p, were suppressed distinctly in ectopic pregnancy, despite elevated tissue expression of the pre-microRNA. A decision-tree model that used kisspeptin and miR-324-3p levels was successful in discriminating ectopic pregnancy vs voluntary termination of pregnancy, with a receiver-operating characteristic area under the curve of 0.95±0.02 (95% confidence interval). CONCLUSION: Our results document a significant down-regulation of KISS1/kisspeptins in early stages of ectopic pregnancy via, at least partially, a repressive interaction with miR-324-3p. Our data identify circulating kisspeptins and miR-324-3p as putative biomarkers for accurate screening of ectopic pregnancy at early gestational ages.
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Embrión de Mamíferos/metabolismo , Kisspeptinas/metabolismo , MicroARNs/metabolismo , Placenta/metabolismo , Embarazo Ectópico/diagnóstico , Biomarcadores/metabolismo , Estudios de Casos y Controles , Árboles de Decisión , Regulación hacia Abajo , Diagnóstico Precoz , Femenino , Edad Gestacional , Humanos , Kisspeptinas/genética , Embarazo , Embarazo Ectópico/metabolismo , ARN Mensajero/metabolismo , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
PURPOSE: The neurokinin B (NKB)/NK3 receptor (NK3R) and kisspeptin (KISS1)/kisspeptin receptor (KISS1R), two systems essential for reproduction, are present in human granulosa cells (GCs) of healthy women and contribute to the control of fertility, at least partially, by acting on the gonads. However, little is known about the expression of these systems in GCs of women with polycystic ovarian syndrome (PCOS). The aim of this study was to analyze the expression of NKB/NK3R and KISS1/KISS1R in mural granulosa (MGCs) and cumulus cells (CCs) of PCOS women. METHODS: A cross-sectional study was performed in 46 healthy women and 43 PCOS women undergoing controlled ovarian stimulation. MGCs and CCs were collected from pre-ovulatory follicles after transvaginal ultrasound-guided oocyte retrieval and the expression of the genes encoding NKB (TAC3), NK3R (TACR3), KISS1, and its receptor (KISS1R) was analyzed using real-time quantitative RT-PCR. RESULTS: TAC3, TACR3, and KISS1 mRNA levels were decreased in MGCs and CCs of PCOS women. TAC3 positively correlated with KISS1 in MGCs of healthy women and TACR3 was positively associated with KISS1R in CCs from healthy women. These associations were not observed in PCOS women. CONCLUSION: The NKB/NK3R and KISS1/KISS1R systems are dysregulated in MGCs and CCs of PCOS women. The lower expression of these systems in GCs could contribute to the abnormal follicle development and defective ovulation that characterize the pathogenesis of PCOS.
Asunto(s)
Células del Cúmulo/metabolismo , Células de la Granulosa/metabolismo , Kisspeptinas/genética , Neuroquinina B/genética , Síndrome del Ovario Poliquístico/genética , Receptores de Kisspeptina-1/genética , Receptores de Neuroquinina-3/genética , Adulto , Estudios de Casos y Controles , Células Cultivadas , Estudios Transversales , Células del Cúmulo/patología , Femenino , Regulación de la Expresión Génica , Células de la Granulosa/patología , Humanos , Kisspeptinas/metabolismo , Neuroquinina B/metabolismo , Síndrome del Ovario Poliquístico/metabolismo , Síndrome del Ovario Poliquístico/patología , Receptores de Kisspeptina-1/metabolismo , Receptores de Neuroquinina-3/metabolismo , Adulto JovenRESUMEN
Background: Olanzapine is an orexigenic antipsychotic drug associated with serious metabolic adverse effects in humans. Development of valid rodent models for antipsychotic-induced metabolic adverse effects is hampered by the fact that such effects occur in females only. Estradiol is a predominant female hormone that regulates energy balance. We hypothesized that the female-specific hyperphagia and weight gain induced by olanzapine in the rat are dependent on the presence of estrogens. Methods: Female sham-operated or ovariectomized rats were treated with a single injection of olanzapine depot formulation. Food intake, body weight, plasma lipids, lipogenic gene expression, energy expenditure, and thermogenic markers including brown adipose tissue uncoupling protein 1 protein levels were measured. Olanzapine was also administered to ovariectomized rats receiving estradiol replacement via the subcutaneous (peripheral) or intracerebroventricular route. Results: Orexigenic effects of olanzapine were lost in ovariectomized female rats. Ovariectomized rats treated with olanzapine had less pronounced weight gain than expected from their food intake. Accordingly, brown adipose tissue temperature and protein levels of uncoupling protein 1 were elevated. Replacement in ovariectomized rats with either peripherally or centrally administered estradiol reduced food intake and body weight. Cotreatment with olanzapine blocked the anorexigenic effect of peripheral, but not central estradiol. Conclusions: Our results indicate that the ovarian hormone estradiol plays an important role in olanzapine-induced hyperphagia in female rats and pinpoint the complex effects of olanzapine on the balance between energy intake and thermogenesis.
Asunto(s)
Antipsicóticos/farmacología , Benzodiazepinas/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Ovario/fisiología , Proteína Desacopladora 1/metabolismo , Animales , Peso Corporal/efectos de los fármacos , Ingestión de Alimentos/efectos de los fármacos , Ingestión de Energía/efectos de los fármacos , Estradiol/metabolismo , Femenino , Inyecciones Intraventriculares , Lípidos/sangre , Olanzapina , Ovariectomía , Ovario/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Proteína Desacopladora 1/genética , Aumento de PesoRESUMEN
Physiologically, estrogens carry out a myriad of functions, the most essential being the regulation of the reproductive axis. Currently, it is also dogmatic that estrogens play an important role modulating energy balance and metabolism. In this sense, it is well known that low estrogens levels, occurring due to ovarian insufficiency, in conditions such as menopause or ovariectomy (OVX), are associated with increased food intake and decreased energy expenditure, leading to weight gain and obesity at long term. Concerning energy expenditure, the main effect of estradiol (E2) is on brown adipose tissue (BAT) thermogenesis. Thus, acting through a peripheral or a central action, E2 activates brown fat activity and increases body temperature, which is negatively associated with body weight. Centrally, the hypothalamic AMP-activated protein kinase (AMPK) mediates the E2 action on BAT thermogenesis. In this chapter, we will summarize E2 regulation of BAT thermogenesis and how this can influence energy balance and metabolism in general.
Asunto(s)
Tejido Adiposo Pardo/metabolismo , Metabolismo Energético , Estradiol/metabolismo , Termogénesis , Proteínas Quinasas Activadas por AMP/metabolismo , Tejido Adiposo Pardo/efectos de los fármacos , Animales , Metabolismo Energético/efectos de los fármacos , Estradiol/farmacología , Femenino , Humanos , Hipotálamo/metabolismo , Masculino , Transducción de Señal , Termogénesis/efectos de los fármacosRESUMEN
The peptides of the tachykinin family participate in the regulation of reproductive function acting at both central and peripheral levels. Our previous data showed that treatment of rats with a tachykinin NK3R antagonist caused a reduction of litter size. In the present study, we analyzed the expression of tachykinins and tachykinin receptors in the rat uterus during early pregnancy. Uterine samples were obtained from early pregnant rats (Days 1-9 of pregnancy) and from nonpregnant rats during the proestrus stage of the ovarian cycle, and real-time quantitative RT-PCR, immunohistochemistry, and Western blot studies were used to investigate the pattern of expression of tachykinins and tachykinin receptors. We found that all tachykinins and tachykinin receptors were locally synthesized in the uterus of early pregnant rats. The expression of substance P, neurokinin B, and the tachykinin receptors NK1R and NK3R mRNAs and proteins underwent major changes during the days around implantation and they were widely distributed in implantation sites, being particularly abundant in decidual cells. These findings support the involvement of the tachykinin system in the series of uterine events that occur around embryo implantation in the rat.
Asunto(s)
Receptores de Taquicininas/biosíntesis , Taquicininas/biosíntesis , Útero/metabolismo , Animales , Decidua/citología , Decidua/metabolismo , Implantación del Embrión/efectos de los fármacos , Femenino , Tamaño de la Camada/efectos de los fármacos , Neuroquinina B/biosíntesis , Embarazo , Proestro , Ratas , Ratas Wistar , Receptores de Neuroquinina-1/biosíntesis , Receptores de Neuroquinina-2/antagonistas & inhibidores , Receptores de Neuroquinina-2/biosíntesis , Receptores de Taquicininas/antagonistas & inhibidores , Sustancia P/biosíntesisRESUMEN
Central ceramides regulate energy metabolism by impacting hypothalamic neurons. This allows ceramides to integrate endocrine signals - such as leptin, ghrelin, thyroid hormones, or estradiol - and to modulate the central control of puberty. In this forum article we discuss recent evidence suggesting that specific ceramide species and neuronal populations are involved in these effects.
RESUMEN
Kisspeptins are essential regulators of the reproductive axis, with capacity to potently activate gonadotropin-releasing hormone neurons, acting also as central conduits for the metabolic regulation of fertility. Recent evidence suggests that kisspeptins per se may also modulate several metabolic parameters, including body weight, food intake or energy expenditure, but their actual roles and site(s) of action remain unclear. We present herein a series of studies addressing the metabolic effects of central and peripheral administration of kisspeptin-10 (Kp-10; 1 nmol and 3 nmol daily, respectively) for 11 days in mice of both sexes. To assess direct metabolic actions of Kp-10 versus those derived indirectly from its capacity to modulate gonadal hormone secretion, kisspeptin effects were tested in adult male and female mice gonadectomized and supplemented with fixed, physiological doses of testosterone or 17ß-estradiol, respectively. Central administration of Kp-10 decreased food intake in male mice, especially during the dark phase (~50%), which was accompanied by a reduction in total and nocturnal energy expenditure (~16%) and locomotor activity (~70%). In contrast, opposite patterns were detected in female mice, with an increase in total and nocturnal locomotor activity (>65%), despite no changes in food intake or energy expenditure. These changes were independent of body weight, as no differences were detected in mice of both sexes at the end of Kp-10 treatments. Peripheral administration of Kp-10 failed to alter any of the metabolic parameters analyzed, except for a decrease in locomotor activity in male mice and a subtle increase in 24 h food intake in female mice, denoting a predominant central role of kisspeptins in the control of energy metabolism. Finally, glucose tolerance and insulin sensitivity were not significantly affected by central or peripheral treatment with Kp-10. In conclusion, our data reveal a potential role of kisspeptins in the control of key metabolic parameters, including food intake, energy expenditure and locomotor activity, with a preferential action at central level, which is sex steroid-independent but sexually dimorphic.
RESUMEN
An individual's nutritional status has a powerful effect on sexual maturation. Puberty onset is delayed in response to chronic energy insufficiency and is advanced under energy abundance. The consequences of altered pubertal timing for human health are profound. Late puberty increases the chances of cardiometabolic, musculoskeletal and neurocognitive disorders, whereas early puberty is associated with increased risks of adult obesity, type 2 diabetes mellitus, cardiovascular diseases and various cancers, such as breast, endometrial and prostate cancer. Kennedy and Mitra's trailblazing studies, published in 1963 and using experimental models, were the first to demonstrate that nutrition is a key factor in puberty onset. Building on this work, the field has advanced substantially in the past decade, which is largely due to the impressive development of molecular tools for experimentation and population genetics. In this Review, we discuss the latest advances in basic and translational sciences underlying the nutritional and metabolic control of pubertal development, with a focus on perspectives and future directions.