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1.
Curr Opin Pharmacol ; 71: 102382, 2023 08.
Article in English | MEDLINE | ID: mdl-37307655

ABSTRACT

Gonadotropin-releasing hormone (GnRH) neurons are the final output pathway for the brain control of reproduction. The activity of this neuronal population, mainly located at the preoptic area of the hypothalamus, is controlled by a plethora of metabolic signals. However, it has been documented that most of these signal impact on GnRH neurons through indirect neuronal circuits, Kiss1, proopiomelanocortin, and neuropeptide Y/agouti-related peptide neurons being some of the most prominent mediators. In this context, compelling evidence has been gathered in recent years on the role of a large range of neuropeptides and energy sensors in the regulation of GnRH neuronal activity through both direct and indirect mechanisms. The present review summarizes some of the most prominent recent advances in our understanding of the peripheral factors and central mechanisms involved in the metabolic control of GnRH neurons.


Subject(s)
Gonadotropin-Releasing Hormone , Neuropeptides , Humans , Gonadotropin-Releasing Hormone/metabolism , Reproduction/physiology , Hypothalamus/metabolism , Neuropeptides/metabolism , Neurons/physiology
2.
Nat Rev Neurol ; 19(6): 371-383, 2023 06.
Article in English | MEDLINE | ID: mdl-37208496

ABSTRACT

The global burden of neurological disorders is substantial and increasing, especially in low-resource settings. The current increased global interest in brain health and its impact on population wellbeing and economic growth, highlighted in the World Health Organization's new Intersectoral Global Action Plan on Epilepsy and other Neurological Disorders 2022-2031, presents an opportunity to rethink the delivery of neurological services. In this Perspective, we highlight the global burden of neurological disorders and propose pragmatic solutions to enhance neurological health, with an emphasis on building global synergies and fostering a 'neurological revolution' across four key pillars - surveillance, prevention, acute care and rehabilitation - termed the neurological quadrangle. Innovative strategies for achieving this transformation include the recognition and promotion of holistic, spiritual and planetary health. These strategies can be deployed through co-design and co-implementation to create equitable and inclusive access to services for the promotion, protection and recovery of neurological health in all human populations across the life course.


Subject(s)
Brain , Global Health , International Cooperation , Nervous System Diseases , Neurology , Humans , Biomedical Research , Environmental Policy , Global Health/trends , Goals , Holistic Health , Mental Health , Nervous System Diseases/epidemiology , Nervous System Diseases/prevention & control , Nervous System Diseases/rehabilitation , Nervous System Diseases/therapy , Neurology/methods , Neurology/trends , Spiritualism , Stakeholder Participation , Sustainable Development , World Health Organization
3.
Metabolism ; 129: 155141, 2022 04.
Article in English | MEDLINE | ID: mdl-35074314

ABSTRACT

BACKGROUND: Perturbations in the timing of puberty, with potential adverse consequences in later health, are increasingly common. The underlying neurohormonal mechanisms are unfolded, but nutritional alterations are key contributors. Efforts to unveil the basis of normal puberty and its metabolic control have focused on mechanisms controlling expression of Kiss1, the gene encoding the puberty-activating neuropeptide, kisspeptin. However, other regulatory phenomena remain ill-defined. Here, we address the putative role of the G protein-coupled-receptor kinase-2, GRK2, in GnRH neurons, as modulator of pubertal timing via repression of the actions of kisspeptin, in normal maturation and conditions of nutritional deficiency. METHODS: Hypothalamic RNA and protein expression analyses were conducted in maturing female rats. Pharmacological studies involved central administration of GRK2 inhibitor, ßARK1-I, and assessment of gonadotropin responses to kisspeptin or phenotypic and hormonal markers of puberty, under normal nutrition or early subnutrition in female rats. In addition, a mouse line with selective ablation of GRK2 in GnRH neurons, aka G-GRKO, was generated, in which hormonal responses to kisspeptin and puberty onset were monitored, in normal conditions and after nutritional deprivation. RESULTS: Hypothalamic GRK2 expression increased along postnatal maturation in female rats, especially in the preoptic area, where most GnRH neurons reside, but decreased during the juvenile-to-pubertal transition. Blockade of GRK2 activity enhanced Ca+2 responses to kisspeptin in vitro, while central inhibition of GRK2 in vivo augmented gonadotropin responses to kisspeptin and advanced puberty onset. Postnatal undernutrition increased hypothalamic GRK2 expression and delayed puberty onset, the latter being partially reversed by central GRK2 inhibition. Conditional ablation of GRK2 in GnRH neurons enhanced gonadotropin responses to kisspeptin, accelerated puberty onset, and increased LH pulse frequency, while partially prevented the negative impact of subnutrition on pubertal timing and LH pulsatility in mice. CONCLUSIONS: Our data disclose a novel pathway whereby GRK2 negatively regulates kisspeptin actions in GnRH neurons, as major regulatory mechanism for tuning pubertal timing in nutritionally-compromised conditions.


Subject(s)
Kisspeptins , Malnutrition , Animals , Female , Gonadotropin-Releasing Hormone/metabolism , Hypothalamus/metabolism , Kisspeptins/genetics , Malnutrition/metabolism , Mice , Neurons/metabolism , Rats , Receptors, Kisspeptin-1/metabolism , Sexual Maturation/physiology
4.
Nat Metab ; 3(10): 1415-1431, 2021 10.
Article in English | MEDLINE | ID: mdl-34675439

ABSTRACT

Current pharmacological therapies for treating obesity are of limited efficacy. Genetic ablation or loss of function of AMP-activated protein kinase alpha 1 (AMPKα1) in steroidogenic factor 1 (SF1) neurons of the ventromedial nucleus of the hypothalamus (VMH) induces feeding-independent resistance to obesity due to sympathetic activation of brown adipose tissue (BAT) thermogenesis. Here, we show that body weight of obese mice can be reduced by intravenous injection of small extracellular vesicles (sEVs) delivering a plasmid encoding an AMPKα1 dominant negative mutant (AMPKα1-DN) targeted to VMH-SF1 neurons. The beneficial effect of SF1-AMPKα1-DN-loaded sEVs is feeding-independent and involves sympathetic nerve activation and increased UCP1-dependent thermogenesis in BAT. Our results underscore the potential of sEVs to specifically target AMPK in hypothalamic neurons and introduce a broader strategy to manipulate body weight and reduce obesity.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Adipose Tissue, Brown/enzymology , Extracellular Vesicles/metabolism , Hypothalamus/enzymology , Obesity/metabolism , Animals , Energy Metabolism , Mice , Thermogenesis , Weight Loss
5.
Cell Metab ; 32(6): 951-966.e8, 2020 12 01.
Article in English | MEDLINE | ID: mdl-33080217

ABSTRACT

Childhood obesity, especially in girls, is frequently bound to earlier puberty, which is linked to higher disease burden later in life. The mechanisms underlying this association remain elusive. Here we show that brain ceramides participate in the control of female puberty and contribute to its alteration in early-onset obesity in rats. Postnatal overweight caused earlier puberty and increased hypothalamic ceramide content, while pharmacological activation of ceramide synthesis mimicked the pubertal advancement caused by obesity, specifically in females. Conversely, central blockade of de novo ceramide synthesis delayed puberty and prevented the effects of the puberty-activating signal, kisspeptin. This phenomenon seemingly involves a circuit encompassing the paraventricular nucleus (PVN) and ovarian sympathetic innervation. Early-onset obesity enhanced PVN expression of SPTLC1, a key enzyme for ceramide synthesis, and advanced the maturation of the ovarian noradrenergic system. In turn, obesity-induced pubertal precocity was reversed by virogenetic suppression of SPTLC1 in the PVN. Our data unveil a pathway, linking kisspeptin, PVN ceramides, and sympathetic ovarian innervation, as key for obesity-induced pubertal precocity.


Subject(s)
Ceramides/metabolism , Hypothalamus/metabolism , Kisspeptins/metabolism , Ovary/metabolism , Pediatric Obesity , Puberty, Precocious , Animals , Female , Male , Pediatric Obesity/complications , Pediatric Obesity/metabolism , Puberty, Precocious/etiology , Puberty, Precocious/metabolism , Rats, Wistar
6.
Sci Rep ; 10(1): 7448, 2020 05 04.
Article in English | MEDLINE | ID: mdl-32366946

ABSTRACT

Cholesterol Gallstone Disease (GSD) is a common multifactorial disorder characterized by crystallization and aggregation of biliary cholesterol in the gallbladder. The global prevalence of GSD is ~10-20% in the adult population but rises to 28% in Chile (17% among men and 30% among women). The small intestine may play a role in GSD pathogenesis, but the molecular mechanisms have not been clarified. Our aim was to identify the role of the small intestine in GSD pathogenesis. Duodenal biopsy samples were obtained from patients with GSD and healthy volunteers. GSD status was defined by abdominal ultrasonography. We performed a transcriptome study in a discovery cohort using Illumina HiSeq. 2500, and qPCR, immunohistochemistry and immunofluorescence were used to validate differentially expressed genes among additional case-control cohorts. 548 differentially expressed genes between GSD and control subjects were identified. Enriched biological processes related to cellular response to zinc, and immune and antimicrobial responses were observed in GSD patients. We validated lower transcript levels of metallothionein, NPC1L1 and tight junction genes and higher transcript levels of genes involved in immune and antimicrobial pathways in GSD patients. Interestingly, serum zinc and phytosterol to cholesterol precursor ratios were lower in GSD patients. A significant association was observed between serum zinc and phytosterol levels. Our results support a model where proximal small intestine plays a key role in GSD pathogenesis. Zinc supplementation, modulation of proximal microbiota and/or intestinal barrier may be novel targets for strategies to prevent GSD.


Subject(s)
Cholelithiasis/metabolism , Cholesterol/metabolism , Duodenum/metabolism , Inflammation/metabolism , Tight Junctions/metabolism , Zinc/metabolism , Adult , Biopsy , Cholelithiasis/diagnostic imaging , Cholelithiasis/pathology , Female , Gene Expression Regulation , Humans , Male , Membrane Transport Proteins/metabolism , Metallothionein/metabolism , Microbiota , Prevalence , RNA-Seq , Risk Factors , Tight Junction Proteins/metabolism , Transcriptome , Ultrasonography , Young Adult
7.
PLoS Biol ; 17(11): e3000532, 2019 11.
Article in English | MEDLINE | ID: mdl-31697675

ABSTRACT

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.


Subject(s)
Hypothalamus/metabolism , MicroRNAs/physiology , Sexual Maturation/genetics , Ubiquitin-Protein Ligases/genetics , Animals , Binding Sites , Cell Line , Female , Gene Expression Regulation, Developmental , Male , MicroRNAs/metabolism , Rats , Sequence Analysis, DNA
8.
Semin Reprod Med ; 37(4): 155-165, 2019 07.
Article in English | MEDLINE | ID: mdl-31972860

ABSTRACT

Puberty is a fundamental developmental event in the lifespan of any individual, when sexual and somatic maturation is completed, and reproductive capacity is achieved. While the tempo of puberty is under strong genetic determination, it is also modulated by a wide array of internal and environmental cues, including, prominently, nutritional and metabolic signals. In the last decade, our understanding of the neurohormonal basis of normal puberty and its perturbations has enlarged considerably. This is illustrated by the elucidation of the essential roles of kisspeptins, encoded by the Kiss1 gene, in the hypothalamic circuits controlling puberty. Moreover, other neuropeptide pathways, convergent with kisspeptin signaling, have been pointed out as important coregulators of pubertal timing. These include the cotransmitters of Kiss1 neurons in the arcuate nucleus (ARC), neurokinin B, and dynorphin, as well as melanocortins, produced by ARC neurons expressing proopiomelanocortin, which are endowed with key roles also in the control of metabolic homeostasis. This neuropeptide setup seemingly participates, in a coordinated manner, in transmitting the regulatory actions of metabolic cues on pubertal maturation. In this function, cellular metabolic sensors, such as the AMP-activated protein kinase, and the fuel-sensing deacetylase, SIRT1, have also been shown recently to contribute to the metabolic regulation of puberty. Altogether, elucidation of the physiological roles of these signals and regulatory circuits will help uncover the intimacies of the brain control of puberty, and its alterations in conditions of metabolic stress, ranging from subnutrition to obesity.


Subject(s)
Neuropeptides/physiology , Puberty/physiology , Animals , Humans , Hypothalamus/metabolism , Hypothalamus/physiology , Kisspeptins/metabolism , Neurokinin B/metabolism , Neurons/metabolism , Neurons/physiology , Neuropeptides/pharmacology , Puberty/drug effects , Reproduction/physiology , Sexual Maturation/drug effects , Sexual Maturation/physiology , Signal Transduction/drug effects , Signal Transduction/physiology
9.
Metabolism ; 87: 87-97, 2018 10.
Article in English | MEDLINE | ID: mdl-30075164

ABSTRACT

BACKGROUND: RF-amide-related peptide-3 (RFRP-3), the mammalian ortholog of gonadotropin-inhibiting hormone, operates as inhibitory signal for the reproductive axis. Recently, RFRP-3 has been also suggested to stimulate feeding, and therefore might contribute to the control of body weight and its alterations. Yet, characterization of the metabolic actions of RFRP-3 has been so far superficial and mostly pharmacological. Here, we aim to investigate the physiological roles of RFRP-3 signaling in the control of feeding and metabolic homeostasis using a novel mouse model of genetic ablation of its canonical receptor, NPFF1R. METHODS: Food intake, body weight gain and composition, and key metabolic parameters, including glucose tolerance and insulin sensitivity, were monitored in mice with constitutive inactivation of NPFF1R. RESULTS: Congenital elimination of NPFF1R in male mice resulted in changes in feeding patterns, with a decrease in spontaneous food intake and altered responses to leptin and ghrelin: leptin-induced feeding suppression was exaggerated in NPFF1R null mice, whereas orexigenic responses to ghrelin were partially blunted. Concordant with this pro-anorectic phenotype, hypothalamic expression of Pomc was increased in NPFF1R null mice. In contrast, spontaneous feeding and neuropeptide expression remained unaltered in NPFF1R KO female mice. Despite propensity for reduced feeding, ablation of NPFF1R signaling in male mice did not cause overt alterations in body weight (BW) gain or composition, neither it affected BW responses to high fat diet (HFD), total energy expenditure or RQ ratios. Yet, NPFF1R KO males showed a decrease in locomotor activity. Conversely, NPFF1R null female mice tended to be heavier and displayed exaggerated BW increases in response to obesogenic insults, such as HFD or ovariectomy. These were associated to increased fat mass, decreased total energy expenditure in HFD, and unaltered RQ ratios or spontaneous locomotor activity. Finally, lack of NPFF1R signaling worsened the metabolic impact of HFD on glycemic homeostasis in males, as revealed by impaired glucose tolerance and insulin sensitivity, while female mice remained unaffected. CONCLUSION: Our data support a discernible orexigenic role of NPFF1R signaling selectively in males, which might modulate the effects of leptin and ghrelin on food intake. In addition, our study is the first to disclose the sex-biased, deleterious impact of the lack of NPFF1R signaling on body weight and fat composition, energy expenditure, locomotor activity and glucose balance, which exaggerates some of the metabolic consequences of concurrent obesogenic insults, such as HFD, in a sexually dimorphic manner. SUMMARY OF TRANSLATIONAL RELEVANCE: Our data are the first to document the nature and magnitude of the regulatory actions of RFRP-3/NPFF1R signaling in the control of feeding and metabolic homeostasis in a physiological setting. Our results not only suggest an orexigenic action of endogenous RFRP-3, specifically in males, but reveal also the detrimental impact of ablation of NPFF1R signaling on body composition, energy expenditure, locomotor activity or glucose balance, especially when concurrent with other obesogenic insults, as HFD, thereby providing the first evidence for additional metabolic effects of RFRP-3, other that the mere control of feeding. Interestingly, alterations of such key metabolic parameters occurred in a sex-biased manner, with males being more sensitive to deregulation of locomotor activity and glycemic control, while females displayed clearer obesogenic responses and deregulated energy expenditure. While our study cannot discard the possibility of RFRP-3 actions via alternative pathways, such as NPFF2R, our data pave the way for future analyses addressing the eventual contribution of altered RFRP-3/NPFF1R signaling in the development of metabolic alterations (including obesity and its comorbidities), especially in conditions associated to reproductive dysfunction.


Subject(s)
Eating/genetics , Eating/physiology , Neuropeptides/metabolism , Receptors, Neuropeptide/genetics , Receptors, Neuropeptide/physiology , Animals , Body Composition/genetics , Diet, High-Fat , Energy Metabolism/genetics , Ghrelin/pharmacology , Glucose Intolerance/genetics , Homeostasis , Hypothalamus/metabolism , Insulin Resistance/genetics , Leptin/pharmacology , Male , Mice , Mice, Knockout , Sex Characteristics , Weight Gain/genetics
10.
Cell Metab ; 26(1): 212-229.e12, 2017 Jul 05.
Article in English | MEDLINE | ID: mdl-28683288

ABSTRACT

Thyroid hormones (THs) act in the brain to modulate energy balance. We show that central triiodothyronine (T3) regulates de novo lipogenesis in liver and lipid oxidation in brown adipose tissue (BAT) through the parasympathetic (PSNS) and sympathetic nervous system (SNS), respectively. Central T3 promotes hepatic lipogenesis with parallel stimulation of the thermogenic program in BAT. The action of T3 depends on AMP-activated protein kinase (AMPK)-induced regulation of two signaling pathways in the ventromedial nucleus of the hypothalamus (VMH): decreased ceramide-induced endoplasmic reticulum (ER) stress, which promotes BAT thermogenesis, and increased c-Jun N-terminal kinase (JNK) activation, which controls hepatic lipid metabolism. Of note, ablation of AMPKα1 in steroidogenic factor 1 (SF1) neurons of the VMH fully recapitulated the effect of central T3, pointing to this population in mediating the effect of central THs on metabolism. Overall, these findings uncover the underlying pathways through which central T3 modulates peripheral metabolism.


Subject(s)
Energy Metabolism , Hypothalamus/metabolism , Mitogen-Activated Protein Kinase 8/metabolism , Signal Transduction , Thyroid Hormones/metabolism , Adipose Tissue, Brown/metabolism , Animals , Lipid Metabolism , Liver/metabolism , Male , Mice, Inbred C57BL , Rats , Rats, Sprague-Dawley , Thermogenesis , Triiodothyronine/metabolism
11.
Nat Neurosci ; 19(6): 835-44, 2016 06.
Article in English | MEDLINE | ID: mdl-27135215

ABSTRACT

A sparse population of a few hundred primarily hypothalamic neurons forms the hub of a complex neuroglial network that controls reproduction in mammals by secreting the 'master molecule' gonadotropin-releasing hormone (GnRH). Timely postnatal changes in GnRH expression are essential for puberty and adult fertility. Here we report that a multilayered microRNA-operated switch with built-in feedback governs increased GnRH expression during the infantile-to-juvenile transition and that impairing microRNA synthesis in GnRH neurons leads to hypogonadotropic hypogonadism and infertility in mice. Two essential components of this switch, miR-200 and miR-155, respectively regulate Zeb1, a repressor of Gnrh transcriptional activators and Gnrh itself, and Cebpb, a nitric oxide-mediated repressor of Gnrh that acts both directly and through Zeb1, in GnRH neurons. This alteration in the delicate balance between inductive and repressive signals induces the normal GnRH-fuelled run-up to correct puberty initiation, and interfering with this process disrupts the neuroendocrine control of reproduction.


Subject(s)
Gonadotropin-Releasing Hormone/genetics , Gonadotropin-Releasing Hormone/metabolism , MicroRNAs/metabolism , Reproduction/physiology , Sexual Maturation/physiology , Aging , Animals , Fertility/physiology , Hypogonadism/metabolism , Hypothalamus/metabolism , Mice, Inbred C57BL , Mice, Transgenic
12.
Liver Int ; 35(9): 2129-38, 2015 Sep.
Article in English | MEDLINE | ID: mdl-25646700

ABSTRACT

BACKGROUND: Therapeutic options to treat Non-alcoholic steatohepatitis (NASH) are limited. Mineralocorticoid receptor (MR) activation could play a role in hepatic fibrogenesis and its modulation could be beneficial for NASH. AIM: To investigate whether eplerenone, a specific MR antagonist, ameliorates liver damage in experimental NASH. METHODS: C57bl6 mice were fed a choline-deficient and amino acid-defined (CDAA) diet for 22 weeks with or without eplerenone supplementation. Serum levels of aminotransferases and aldosterone were measured and hepatic steatosis, inflammation and fibrosis scored histologically. Hepatic triglyceride content (HTC) and hepatic mRNA levels of pro-inflammatory pro-fibrotic, oxidative stress-associated genes and of MR were also assessed. RESULTS: CDAA diet effectively induced fibrotic NASH, and increased the hepatic expression of pro-inflammatory, pro-fibrotic and oxidative stress-associated genes. Hepatic MR mRNA levels significantly correlated with the expression of pro-inflammatory and pro-fibrotic genes and were significantly increased in hepatic stellate cells obtained from CDAA-fed animals. Eplerenone administration was associated to a reduction in histological steatosis and attenuation of liver fibrosis development, which was associated to a significant decrease in the expression of collagen-α1, collagen type III, alpha 1 and Matrix metalloproteinase-2. CONCLUSION: The expression of MR correlates with inflammation and fibrosis development in experimental NASH. Specific MR blockade with eplerenone has hepatic anti-steatotic and anti-fibrotic effects. These data identify eplerenone as a potential novel therapy for NASH. Considering its safety and FDA-approved status, human studies are warranted.


Subject(s)
Liver Cirrhosis/pathology , Mineralocorticoid Receptor Antagonists/administration & dosage , Non-alcoholic Fatty Liver Disease/drug therapy , Oxidative Stress/genetics , Receptors, Mineralocorticoid/metabolism , Spironolactone/analogs & derivatives , Animals , Biomarkers/analysis , Disease Models, Animal , Eplerenone , Liver/pathology , Male , Mice , Mice, Inbred C57BL , Receptors, Mineralocorticoid/genetics , Spironolactone/administration & dosage
13.
Nat Commun ; 4: 2492, 2013.
Article in English | MEDLINE | ID: mdl-24051579

ABSTRACT

Signaling between kisspeptin and its receptor, G-protein-coupled receptor 54 (Gpr54), is now recognized as being essential for normal fertility. However, the key cellular location of kisspeptin-Gpr54 signaling is unknown. Here we create a mouse with a GnRH neuron-specific deletion of Gpr54 to assess the role of gonadotropin-releasing hormone (GnRH) neurons. Mutant mice are infertile, fail to go through puberty and exhibit markedly reduced gonadal size and follicle-stimulating hormone levels alongside GnRH neurons that are unresponsive to kisspeptin. In an attempt to rescue the infertile phenotype of global Gpr54⁻/⁻ mutants, we use BAC transgenesis to target Gpr54 to the GnRH neurons. This results in mice with normal puberty onset, estrous cyclicity, fecundity and a recovery of kisspeptin's stimulatory action upon GnRH neurons. Using complimentary cell-specific knockout and knockin approaches we demonstrate here that the GnRH neuron is the key site of kisspeptin-Gpr54 signaling for fertility.


Subject(s)
Gonadotropin-Releasing Hormone/genetics , Hypothalamus/metabolism , Infertility/genetics , Kisspeptins/genetics , Neurons/metabolism , Receptors, G-Protein-Coupled/genetics , Signal Transduction , Animals , Female , Fertility/genetics , Gene Expression Regulation, Developmental , Gene Knock-In Techniques , Gonadotropin-Releasing Hormone/metabolism , Hypothalamus/pathology , Infertility/metabolism , Infertility/pathology , Kisspeptins/metabolism , Mice , Mice, Knockout , Neurons/pathology , Organ Size , Ovary/metabolism , Ovary/pathology , Receptors, G-Protein-Coupled/metabolism , Receptors, Kisspeptin-1 , Sexual Maturation
14.
J Pathol ; 227(2): 209-22, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22294347

ABSTRACT

Hyperthyroidism is characterized in rats by increased energy expenditure and marked hyperphagia. Alterations of thermogenesis linked to hyperthyroidism are associated with dysregulation of hypothalamic AMPK and fatty acid metabolism; however, the central mechanisms mediating hyperthyroidism-induced hyperphagia remain largely unclear. Here, we demonstrate that hyperthyroid rats exhibit marked up-regulation of the hypothalamic mammalian target of rapamycin (mTOR) signalling pathway associated with increased mRNA levels of agouti-related protein (AgRP) and neuropeptide Y (NPY), and decreased mRNA levels of pro-opiomelanocortin (POMC) in the arcuate nucleus of the hypothalamus (ARC), an area where mTOR co-localizes with thyroid hormone receptor-α (TRα). Central administration of thyroid hormone (T3) or genetic activation of thyroid hormone signalling in the ARC recapitulated hyperthyroidism effects on feeding and the mTOR pathway. In turn, central inhibition of mTOR signalling with rapamycin in hyperthyroid rats reversed hyperphagia and normalized the expression of ARC-derived neuropeptides, resulting in substantial body weight loss. The data indicate that in the hyperthyroid state, increased feeding is associated with thyroid hormone-induced up-regulation of mTOR signalling. Furthermore, our findings that different neuronal modulations influence food intake and energy expenditure in hyperthyroidism pave the way for a more rational design of specific and selective therapeutic compounds aimed at reversing the metabolic consequences of this disease.


Subject(s)
Eating , Feeding Behavior , Hyperphagia/etiology , Hyperthyroidism/complications , Hypothalamus/enzymology , Signal Transduction , TOR Serine-Threonine Kinases/metabolism , AMP-Activated Protein Kinases/metabolism , Agouti-Related Protein/genetics , Animals , Disease Models, Animal , Eating/drug effects , Feeding Behavior/drug effects , Hyperphagia/enzymology , Hyperphagia/genetics , Hyperphagia/physiopathology , Hyperphagia/prevention & control , Hyperthyroidism/chemically induced , Hyperthyroidism/enzymology , Hyperthyroidism/genetics , Hyperthyroidism/physiopathology , Hypothalamus/drug effects , Hypothalamus/physiopathology , Male , Neural Pathways/drug effects , Neural Pathways/enzymology , Neuropeptide Y/genetics , Phosphorylation , Pro-Opiomelanocortin/genetics , Protein Kinase Inhibitors/pharmacology , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Signal Transduction/drug effects , Sirolimus/pharmacology , TOR Serine-Threonine Kinases/antagonists & inhibitors , Thyroid Hormone Receptors alpha/metabolism , Time Factors , Triiodothyronine , Weight Loss
15.
Endocrinology ; 152(4): 1541-50, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21325051

ABSTRACT

The hormone leptin modulates a diverse range of biological functions, including energy homeostasis and reproduction. Leptin promotes GnRH function via an indirect action on forebrain neurons. We tested whether leptin deficiency or leptin resistance due to a high-fat diet (HFD) can regulate the potent reproductive neuropeptide kisspeptin. In mice with normalized levels of estradiol, leptin deficiency markedly reduced kisspeptin gene expression, particularly in the arcuate nucleus (ARC), and kisspeptin immunoreactive cell numbers in the rostral periventricular region of the third ventricle (RP3V). The HFD model was used to determine the effects of diet-induced obesity and central leptin resistance on kisspeptin cell number and gene expression. DBA/2J mice, which are prone to HFD-induced infertility, showed a marked decrease in kisspeptin expression in both the RP3V and ARC and cell numbers in the RP3V after HFD. This is the first evidence that kisspeptin can be regulated by HFD and/or increased body weight. Next we demonstrated that leptin does not signal (via signal transducer and activator of transcription 3 or 5, or mammalian target of rapamycin) directly on kisspeptin-expressing neurons in the RP3V. Lastly, in leptin receptor-deficient mice, neither GnRH nor kisspeptin neurons were activated during a preovulatory-like GnRH/LH surge induction regime, indicating that leptin's actions on GnRH may be upstream of kisspeptin neurons. These data provide evidence that leptin's effects on reproductive function are regulated by kisspeptin neurons in both the ARC and RP3V, although in the latter site the effects are likely to be indirect.


Subject(s)
Dietary Fats/adverse effects , Hypothalamus/metabolism , Leptin/blood , Obesity/metabolism , Tumor Suppressor Proteins/metabolism , Animals , Body Weight/physiology , Enzyme-Linked Immunosorbent Assay , Estradiol/blood , Female , Gonadotropin-Releasing Hormone/metabolism , Immunohistochemistry , Kisspeptins , Leptin/deficiency , Male , Mice , Mice, Inbred C57BL , Neurons/drug effects , Neurons/metabolism , Obesity/chemically induced , Proteins/genetics , Proteins/metabolism , Radioimmunoassay , Reverse Transcriptase Polymerase Chain Reaction , Tumor Suppressor Proteins/genetics
16.
Cancer Biol Ther ; 10(10): 1009-18, 2010 Nov 15.
Article in English | MEDLINE | ID: mdl-20818175

ABSTRACT

Esophageal adenocarcinoma (EAC) arises in the backdrop of reflux-induced metaplastic phenomenon known as Barrett esophagus. The prognosis of advanced EAC is dismal, and there is an urgent need for identifying molecular targets for therapy. Serial Analysis of Gene Expression (SAGE) was performed on metachronous mucosal biopsies from a patient who underwent progression to EAC during endoscopic surveillance. SAGE confirmed significant upregulation of Axl "tags" during the multistep progression of Barrett esophagus to EAC. In a cohort of 92 surgically resected EACs, Axl overexpression was associated with shortened median survival on both univariate (p < 0.004) and multivariate (p < 0.036) analysis. Genetic knockdown of Axl receptor tyrosine kinase (RTK) function was enabled in two EAC lines (OE33 and JH-EsoAd1) using lentiviral short hairpin RNA (shRNA). Genetic knockdown of Axl in EAC cell lines inhibited invasion, migration, and in vivo engraftment, which was accompanied by downregulation in the activity of the Ral GTPase proteins (RalA and RalB). Restoration of Ral activation rescued the transformed phenotype of EAC cell lines, suggesting a novel effector mechanism for Axl in cancer cells. Pharmacological inhibition of Axl was enabled using a small molecule antagonist, R428 (Rigel Pharmaceuticals). Pharmacological inhibition of Axl with R428 in EAC cell lines significantly reduced anchorage-independent growth, invasion and migration. Blockade of Axl function abrogated phosphorylation of ERBB2 (Her-2/neu) at the Tyr877 residue, indicative of receptor crosstalk. Axl RTK is an adverse prognostic factor in EAC. The availability of small molecule inhibitors of Axl function provides a tractable strategy for molecular therapy of established EAC.


Subject(s)
Adenocarcinoma/pathology , Barrett Esophagus/pathology , Esophageal Neoplasms/pathology , Proto-Oncogene Proteins/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , Signal Transduction/drug effects , Adenocarcinoma/drug therapy , Adenocarcinoma/enzymology , Aged , Animals , Barrett Esophagus/drug therapy , Barrett Esophagus/enzymology , Benzocycloheptenes/pharmacology , Cell Movement/drug effects , Esophageal Neoplasms/drug therapy , Esophageal Neoplasms/enzymology , Female , Humans , Immunoenzyme Techniques , Intercellular Signaling Peptides and Proteins/genetics , Intercellular Signaling Peptides and Proteins/metabolism , Lapatinib , Lymphatic Metastasis , Male , Mice , Mice, Inbred NOD , Mice, SCID , Middle Aged , Phosphorylation/drug effects , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins/antagonists & inhibitors , Proto-Oncogene Proteins/genetics , Quinazolines/pharmacology , RNA, Small Interfering/genetics , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Receptor Protein-Tyrosine Kinases/genetics , Survival Rate , Triazoles/pharmacology , ral GTP-Binding Proteins/antagonists & inhibitors , ral GTP-Binding Proteins/genetics , ral GTP-Binding Proteins/metabolism , Axl Receptor Tyrosine Kinase
17.
J Neurosci ; 30(23): 7783-92, 2010 Jun 09.
Article in English | MEDLINE | ID: mdl-20534827

ABSTRACT

The hypothalamic peptide, nesfatin-1, derived from the precursor NEFA/nucleobindin 2 (NUCB2), was recently identified as anorexigenic signal, acting in a leptin-independent manner. Yet its participation in the regulation of other biological functions gated by body energy status remains unexplored. We show herein that NUCB2/nesfatin-1 is involved in the control of female puberty. NUCB2/nesfatin mRNA and protein were detected at the hypothalamus of pubertal female rats, with prominent signals at lateral hypothalamus (LHA), paraventricular (PVN), and supraoptic (SON) nuclei. Hypothalamic NUCB2 expression raised along pubertal transition, with detectable elevations of its mRNA levels at LHA, PVN, and SON, and threefold increase of its total protein content between late-infantile and peripubertal periods. Conditions of negative energy balance, such as 48 h fasting or sustained subnutrition, decreased hypothalamic NUCB2 mRNA and/or protein levels in pubertal females. At this age, central administration of nesfatin-1 induced modest but significant elevations of circulating gonadotropins, whose magnitude was notably augmented in conditions of food deprivation. Continuous intracerebroventricular infusion of antisense morpholino oligonucleotides (as-MONs) against NUCB2 along pubertal maturation, which markedly reduced hypothalamic NUCB2 protein content, delayed vaginal opening and decreased ovarian weights and serum luteinizing hormone (LH) levels. In contrast, in adult female rats, intracerebroventricular injection of nesfatin did not stimulate LH or follicle-stimulating hormone secretion; neither did central as-MON infusion alter preovulatory gonadotropin surges, despite suppression of hypothalamic NUCB2. In sum, our data are the first to disclose the indispensable role of NUCB2/nesfatin-1 in the central networks driving puberty onset, a function that may contribute to its functional coupling to energy homeostasis.


Subject(s)
Calcium-Binding Proteins/metabolism , DNA-Binding Proteins/metabolism , Hypothalamus/metabolism , Nerve Tissue Proteins/metabolism , Nerve Tissue Proteins/pharmacology , Neuropeptides/pharmacology , Sexual Maturation/drug effects , Aging/drug effects , Aging/metabolism , Animals , Calcium-Binding Proteins/genetics , DNA-Binding Proteins/genetics , Female , Follicle Stimulating Hormone/blood , Hypothalamic Area, Lateral/metabolism , Injections, Intraventricular , Luteinizing Hormone/blood , Nerve Tissue Proteins/administration & dosage , Nerve Tissue Proteins/genetics , Neuropeptides/administration & dosage , Neuropeptides/metabolism , Nucleobindins , Oligoribonucleotides, Antisense/administration & dosage , Oligoribonucleotides, Antisense/pharmacology , Paraventricular Hypothalamic Nucleus/metabolism , RNA, Messenger , Rats , Rats, Wistar , Supraoptic Nucleus/metabolism
18.
Acta cir. bras ; 25(3): 225-230, May-June 2010. ilus, tab
Article in English | LILACS | ID: lil-546827

ABSTRACT

PURPOSE: To evaluate the results of a prospective therapeutic protocol with long-term follow up in terms of survival rates in a cohort of patients treated with Intermediate and Advanced GBC (GBC). METHODS: Prospective cohort of patients with intermediate and advanced stages of GBC treated between 1996 and 2006. All cases were treated with a partial hepatic segmentectomy on segments IVb and V and a regional lymph node dissection and six cycles of out-patient chemotherapy (5-FU and leukovorin). With an average follow-up of 31.5 months, the morbidity, operative mortality, hepatic and lymphatic infiltration and actuarial survival were measured. Descriptive statistics were applied as well as bivariate analysis applying Fisher's exact test and non-parametrical tests and Kaplan Meier survival curves. Also logistic regression and proportional risk of Cox were applied. RESULTS: 40 patients were included in this protocol, with an average age of 59.5 years (40-85 years), of which 28 were women (70 percent). Depth of wall infiltration: muscular 8 patients (20 percent), subserosal 12 patients (30 percent), serosal 12 patients (30 percent) and perivesicular adipose tissue 8 patients (20 percent). The series morbidity was 27.5 percent. There was no operative mortality. The chemotherapy was well tolerated. The overall actuarial survival in the series was 50 percent at 60 months. CONCLUSION: Our protocol treatment has morbidity, mortality and survival rates similar to previously reported series.


OBJETIVO: Avaliar os resultados de resultados da aplicação de um protocolo terapêutico de natureza prospectiva, com seguimento em longo prazo nos termos de taxas de sobrevivência em uma coorte de pacientes operados com carcinoma vesícula biliar (CVB) intermédio e avançado. MÉTODOS: A coorte prospectiva de pacientes com estágios intermediários e avançados de CVB tratados entre 1996 e 2006. Todos os casos foram tratados com uma segmentectomia hepática parcial em segmentos IVb e V e uma dissecção linfonodal regional e seis ciclos de quimioterapia de ambulatório (5-FU e leukovorin). Com um tempo de seguimento médio de 31,5 meses, a morbidade, mortalidade operatória, hepático e infiltração linfática e atuarial de sobrevida foram medidas. Estatísticas descritivas foram aplicadas, bem como análise bivariada aplicando o teste exato de Fisher, testes não-paramétricos, curvas de sobrevida Kaplan Meier e técnica de regressão logística e risco proporcional de Cox. RESULTADOS: Foram incluídos 40 pacientes neste protocolo, com uma média de idade de 59,5 anos (40-85 anos), dos quais 28 eram mulheres (70 por cento). Profundidade de infiltração parede: muscular 8 pacientes (20 por cento), subserosal 12 pacientes (30 por cento), serosas 12 pacientes (30 por cento) e perivesicular no tecido adiposo, 8 pacientes (20 por cento). A série morbidade foi de 27,5 por cento. Não houve mortalidade operatória. A quimioterapia foi bem tolerada. A sobrevida global atuarial da série foi de 50 por cento em 60 meses. CONCLUSÃO: Nosso protocolo tem tratamento morbidade, mortalidade e taxas de sobrevivência semelhantes às relatadas anteriormente série.


Subject(s)
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Antineoplastic Agents/therapeutic use , Carcinoma/mortality , Carcinoma/therapy , Fluorouracil/therapeutic use , Gallbladder Neoplasms/mortality , Gallbladder Neoplasms/therapy , Clinical Protocols , Carcinoma/pathology , Chemotherapy, Adjuvant/methods , Chile/epidemiology , Cholecystectomy/methods , Epidemiologic Methods , Gallbladder Neoplasms/pathology , Leucovorin/therapeutic use , Neoplasm Invasiveness , Sex Factors , Treatment Outcome
19.
Acta Cir Bras ; 25(3): 225-30, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20498934

ABSTRACT

PURPOSE: To evaluate the results of a prospective therapeutic protocol with long-term follow up in terms of survival rates in a cohort of patients treated with Intermediate and Advanced GBC (GBC). METHODS: Prospective cohort of patients with intermediate and advanced stages of GBC treated between 1996 and 2006. All cases were treated with a partial hepatic segmentectomy on segments IVb and V and a regional lymph node dissection and six cycles of out-patient chemotherapy (5-FU and leukovorin). With an average follow-up of 31.5 months, the morbidity, operative mortality, hepatic and lymphatic infiltration and actuarial survival were measured. Descriptive statistics were applied as well as bivariate analysis applying Fisher's exact test and non-parametrical tests and Kaplan Meier survival curves. Also logistic regression and proportional risk of Cox were applied. RESULTS: 40 patients were included in this protocol, with an average age of 59.5 years (40-85 years), of which 28 were women (70%). Depth of wall infiltration: muscular 8 patients (20%), subserosal 12 patients (30%), serosal 12 patients (30%) and perivesicular adipose tissue 8 patients (20%). The series morbidity was 27.5%. There was no operative mortality. The chemotherapy was well tolerated. The overall actuarial survival in the series was 50% at 60 months. CONCLUSION: Our protocol treatment has morbidity, mortality and survival rates similar to previously reported series.


Subject(s)
Antineoplastic Agents/therapeutic use , Carcinoma/mortality , Carcinoma/therapy , Fluorouracil/therapeutic use , Gallbladder Neoplasms/mortality , Gallbladder Neoplasms/therapy , Adult , Aged , Aged, 80 and over , Carcinoma/pathology , Chemotherapy, Adjuvant/methods , Chile/epidemiology , Cholecystectomy/methods , Clinical Protocols , Epidemiologic Methods , Female , Gallbladder Neoplasms/pathology , Humans , Leucovorin/therapeutic use , Male , Middle Aged , Neoplasm Invasiveness , Sex Factors , Treatment Outcome
20.
Am J Physiol Endocrinol Metab ; 293(5): E1265-73, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17726140

ABSTRACT

Neuromedin U (NMU) is a widely spread neuropeptide, with predominant expression at the gastrointestinal tract and brain, putatively involved in the regulation of a diversity of biological functions, including food intake, energy balance and circadian rhythms; all closely related to reproduction. Yet, the implication of NMU in the control of the gonadotropic axis remains scarcely studied. We report herein analyses on the hypothalamic expression and function of NMU in different physiological and experimental states of the rat reproductive system. Expression of NMU mRNA at the hypothalamus was persistently detected along female postnatal development, with maximum levels in adulthood that fluctuated across the cycle and were modulated by ovarian steroids. Acute central administration of NMU evoked increases of serum LH levels in pubertal female rats, while repeated injection of NMU tended to advance vaginal opening. Likewise, central injection of NMU increased serum LH concentrations in cycling female rats, with peak responses in estrus. In contrast, NMU significantly inhibited preelevated LH secretion in gonadectomized and kisspeptin-treated rats. Finally, in noncycling females due to photoperiodic manipulation (constant light), hypothalamic NMU mRNA levels were markedly depressed, but relative LH responses to exogenous NMU were significantly augmented. All together, our present data support a predominant stimulatory role of NMU in the control of the female gonadotropic axis, which appears under the influence of developmental, hormonal, and photoperiodic cues, and might contribute to the joint regulation of energy balance, biological rhythms, and reproduction.


Subject(s)
Estrous Cycle/physiology , Gonadal Hormones/physiology , Hypothalamus/physiology , Luteinizing Hormone/metabolism , Neuropeptides/physiology , Animals , Animals, Newborn , Body Weight/physiology , Circadian Rhythm/physiology , Female , Photoperiod , RNA, Messenger/chemistry , RNA, Messenger/genetics , Rats , Rats, Wistar , Reverse Transcriptase Polymerase Chain Reaction , Sexual Maturation/physiology , Statistics, Nonparametric
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