Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion


Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion

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Imbernon M.,University of Santiago de Compostela | Imbernon M.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | Beiroa D.,University of Santiago de Compostela | Beiroa D.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | And 32 more authors.
Gastroenterology | Year: 2013

Background & Aims: Specific neuronal circuits modulate autonomic outflow to liver and white adipose tissue. Melanin-concentrating hormone (MCH)-deficient mice are hypophagic, lean, and do not develop hepatosteatosis when fed a high-fat diet. Herein, we sought to investigate the role of MCH, an orexigenic neuropeptide specifically expressed in the lateral hypothalamic area, on hepatic and adipocyte metabolism. Methods: Chronic central administration of MCH and adenoviral vectors increasing MCH signaling were performed in rats and mice. Vagal denervation was performed to assess its effect on liver metabolism. The peripheral effects on lipid metabolism were assessed by real-time polymerase chain reaction and Western blot. Results: We showed that the activation of MCH receptors promotes nonalcoholic fatty liver disease through the parasympathetic nervous system, whereas it increases fat deposition in white adipose tissue via the suppression of sympathetic traffic. These metabolic actions are independent of parallel changes in food intake and energy expenditure. In the liver, MCH triggers lipid accumulation and lipid uptake, with c-Jun N-terminal kinase being an essential player, whereas in adipocytes MCH induces metabolic pathways that promote lipid storage and decreases lipid mobilization. Genetic activation of MCH receptors or infusion of MCH specifically in the lateral hypothalamic area modulated hepatic lipid metabolism, whereas the specific activation of this receptor in the arcuate nucleus affected adipocyte metabolism. Conclusions: Our findings show that central MCH directly controls hepatic and adipocyte metabolism through different pathways. © 2013 AGA Institute.

Molares Vila A.,University of Vigo | Ruperez Perez de Arrilucea P.,University of California at San Francisco | Caso Pelaez E.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | Gago-Martinez A.,University of Vigo
Journal of Proteomics | Year: 2010

Sample pre-treatment is a critical step for an efficient and reliable analysis and it is highly dependent on the complexity of the matrix. This work shows an example of application of an immunoprecipitation approach using a new magnetic beads-based format, which allows a selective/specific extraction of potential biomarkers from metastatic prostate cancer. Results obtained on the development of this method, and its application for the extraction and pre-concentration of certain biomarkers present in metastatic cell lines of prostate cancer, are presented and discussed. It is concluded that the efficiency of the immunoprecipitation step is clearly compromised by the crosslinking conditions and it is highly dependent on the specificity of selected antibodies. The epoxy magnetic beads used in this work allowed an effective crosslinking of the antibodies contributing to an increased efficiency of the immunoprecipitation step. The optimized conditions for the application of these epoxy magnetic beads for the immunoprecipitation of anti-TUBA3C in metastatic prostate cancer cell line (PC3) are discussed here, as an example of application of the immnuprecipitation approach developed, which resulted in a very efficient tool for a specific extraction and pre-concentration of the targeted protein and, therefore, contributing to the efficiency of further analysis. © 2010.

Castellano J.M.,University of Cordoba, Spain | Castellano J.M.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | Bentsen A.H.,Copenhagen University | Romero M.,University of Cordoba, Spain | And 14 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2010

Severe inflammatory challenges are frequently coupled to decreased food intake and disruption of reproductive function, the latter via deregulation of different signaling pathways that impinge onto GnRH neurons. Recently, the hypothalamic Kiss1 system, a major gatekeeper of GnRH function, was suggested as potential target for transmitting immune-mediated repression of the gonadotropic axis during acute inflammation, and yet key facets of such a phenomenon remain ill defined. Using lipopolysaccharide S (LPS)-treated male rats as model of inflammation, we document herein the pattern of hypothalamic kisspeptin immunoreactivity (IR) and hormonal responses to kisspeptin during the acute inflammatory phase. LPS injections induced a dramatic but transient drop of serum LH and testosterone levels. Suppression of gonadotropic function was associated with a significant decrease in kisspeptin-IR in the arcuate nucleus (ARC) that was not observed under conditions of metabolic stress induced by 48-h fasting. In addition, absolute responses to kisspeptin-10 (Kp-10), in terms of LH and testosterone secretion, were significantly attenuated in LPS-treated males that also displayed a decrease in food intake and body weight. Yet pair-fed males did not show similar alterations in LH and testosterone secretory responses to Kp-10, whose magnitude was preserved, if not augmented, during food restriction. In summary, our data document the impact of acute inflammation on kisspeptin content at the ARC as key center for the neuroendocrine control of reproduction. Our results also suggest that suppressed gonadotropic function following inflammatory challenges might involve a reduction in absolute responsiveness to kisspeptin that is independent of the anorectic effects of inflammation. Copyright © 2010 the American Physiological Society.

Pineda R.,University of Cordoba, Spain | Pineda R.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | Garcia-Galiano D.,University of Cordoba, Spain | Garcia-Galiano D.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | And 15 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2010

RF-amide related peptides (RFRP), as putative mammalian orthologs of the avian gonado-tropin-inhibitory hormone (GnIH), have been proposed as key regulators of gonadotropin secretion in higher vertebrates. Yet considerable debate has arisen recently on their physiological relevance and potential mechanisms and sites of action. Present studies were undertaken to further characterize the effects of RFRP on LH and FSH secretion by a combination of in vivo and in vitro approaches in male and female rats. Initial screening via intracerebroventricular (icv) administration of different analogs of RFRP1 (RFRP1-12 and RFRP1-20) and RFRP3 (RFRP3-8 and RFRP3-17), as well as the related neuropeptide FF (NPFF8), to gonadectomized (GNX) female rats evidenced significant, albeit modest, inhibitory effects on LH secretion only for RFRP3-8 and RFRP3-17, which were detectable at the high dose rage (1 nmol for RFRP3-8, 5 nmol for RFRP3-17). This moderate inhibitory action was also documented after icv administration of RFRP3-8 to intact and GNX male rats. In addition, systemic (intravenous) administration of RFRP3-8 decreased the circulating levels of both gonadotropins in GNX male rats. Likewise, RFRP3-8 inhibited basal and GnRH-stimulated LH secretion by pituitaries from GNX males in vitro. This inhibitory effect was blocked by the antagonist of RFRP receptors, RF9. In summary, our results support a putative inhibitory role of RFRP3 as ortholog of GnIH in the regulation of gonadotropin secretion in mammals, which appears to involve direct pituitary actions as well as potential central (hypothalamic) effects. Copyright © 2010 the American Physiological Society.

Navarro V.M.,University of Washington | Navarro V.M.,University of Cordoba, Spain | Gottsch M.L.,University of Washington | Wu M.,Yale University | And 18 more authors.
Endocrinology | Year: 2011

Kisspeptin (Kiss1) and neurokinin B (NKB) (encoded by the Kiss1 and Tac2 genes, respectively) are indispensable for reproduction. In the female of many species, Kiss1 neurons in the arcuate nucleus (ARC) coexpress dynorphin A and NKB. Such cells have been termed Kiss1/NKB/Dynorphin (KNDy) neurons, which are thought to mediate the negative feedback regulation of GnRH/LH secretion by 17β-estradiol. However, we have less knowledge about the molecular physiology and regulation of Kiss1/Kiss1-expressing neurons in the ARC of the male. Our work focused on the adult male mouse, where we sought evidence for coexpression of these neuropeptides in cells in the ARC, assessed the role of Kiss1 neurons in negative feedback regulation of GnRH/LH secretion by testosterone (T), and investigated the action of NKB on KNDy and GnRH neurons. Results showed that 1) the mRNA encoding Kiss1, NKB, and dynorphin are coexpressed in neurons located in the ARC; 2) Kiss1 and dynorphin A mRNA are regulated by T through estrogen and androgen receptordependent pathways; 3) senktide, an agonist for theNKBreceptor (neurokinin 3 receptor, encoded by Tacr3), stimulates gonadotropin secretion; 4) KNDy neurons express Tacr3, whereas GnRH neurons do not; and 5) senktide activates KNDy neurons but has no discernable effect on GnRH neurons. These observations corroborate the putative role for KNDy neurons in mediating the negative feedback effects of T on GnRH/LH secretion and provide evidence that NKB released from KNDy neurons is part of an auto-feedback loop that generates the pulsatile secretion of Kiss1 and GnRH in the male. Copyright © 2011 by The Endocrine Society.

Garcia-Galiano D.,University of Cordoba, Spain | Garcia-Galiano D.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | Navarro V.M.,University of Cordoba, Spain | Navarro V.M.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | And 24 more authors.
Journal of Neuroscience | Year: 2010

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. Copyright©2010 the authors.

Rosell M.,University of Barcelona | Rosell M.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | Hondares E.,University of Barcelona | Hondares E.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | And 12 more authors.
Endocrinology | Year: 2012

Retinol binding protein-4 (RBP4) is a serum protein involved in the transport of vitamin A. It is known to be produced by the liver and white adipose tissue. RBP4 release by white fat has been proposed to induce insulin resistance. We analyzed the regulation and production of RBP4 in brown adipose tissue. RBP4 gene expression is induced in brown fat from mice exposed to cold or treated with peroxisome proliferator-activated receptor (PPAR) agonists. In brown adipocytes in culture, norepinephrine, cAMP, and activators of PPARγ and PPARα induced RBP4 gene expression and RBP4 protein release. The induction of RBP4 gene expression by norepinephrine required intact PPAR-dependent pathways, as evidenced by impaired response of the RBP4 gene expression to norepinephrine in PPARα-null brown adipocytes or in the presence of inhibitors of PPARγ and PPARα. PPARγ and norepinephrine can also induce the RBP4 gene in white adipocytes, and over expression of PPARα confers regulation by this PPAR subtype to white adipocytes. The RBP4 gene promoter transcription is activated by cAMP, PPARα, and PPARγ. This is mediated by a PPAR-responsive element capable of binding PPARα and PPARγ and required also for activation by cAMP. The induction of the RBP4 gene expression by norepinephrine in brown adipocytes is protein synthesis dependent and requires PPARα-coactivator- 1-α, which acts as a norepinephine-induced coactivator of PPAR on the RBP4 gene. We conclude that PPARγ- and PPARγ-mediated signaling controls RBP4 gene expression and releases in brown adipose tissue, and thermogenic activation induces RBP4 gene expression in brown fat through mechanisms involving PPARγ-coactivator-1-α coactivation of PPAR signaling. Copyright © 2012 by The Endocrine Society.

Seoane-Collazo P.,University of Santiago de Compostela | Seoane-Collazo P.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | Martinez De Morentin P.B.,University of Santiago de Compostela | Martinez De Morentin P.B.,Research Center Biomedica En Red Fisiopatologia Of La Obesidad tricion | And 8 more authors.
Endocrinology | Year: 2014

Nicotine, the main addictive component of tobacco, promotes body weight reduction in humans and rodents. Recent evidence has suggested that nicotine acts in the central nervous system to modulate energy balance. Specifically, nicotine modulates hypothalamic AMP-activated protein kinase to decrease feeding and to increase brown adipose tissue thermogenesis through the sympathetic nervous system, leading to weight loss. Of note, most of this evidence has been obtained in animal models fed with normal diet or low-fat diet (LFD). However, its effectiveness in obese models remains elusive. Because obesity causes resistance towards many factors involved in energy homeostasis, the aim of this study has been to compare the effect of nicotine in a diet-induced obese (DIO) model, namely rats fed a high-fat diet, with rats fed a LFD. Our data show that chronic peripheral nicotine treatment reduced body weight by decreasing food intake and increasing brown adipose tissue thermogenesis in both LFD and DIO rats. This overall negative energy balance was associated to decreased activation of hypothalamic AMP-activated protein kinase in both models. Furthermore, nicotine improved serum lipid profile, decreased insulin serum levels, as well as reduced steatosis, inflammation, and endoplasmic reticulum stress in the liver of DIO rats but not in LFD rats. Overall, this evidence suggests that nicotine diminishes body weight andimproves metabolic disorders linked toDIOandmight offer a clear-cut strategy to developnew therapeutic approaches against obesity and its metabolic complications. Copyright © 2014 by the Endocrine Society.

Schneeberger M.,Institute dInvestigacions Biomediques August Pi i Sunyer IDIBAPS | Schneeberger M.,University of Barcelona | Schneeberger M.,Research Center Biomedica En Red Of Diabetes fermedades Metabolicas Asociadas | Dietrich M.O.,Yale University | And 31 more authors.
Cell | Year: 2013

Summary Mitofusin 2 (MFN2) plays critical roles in both mitochondrial fusion and the establishment of mitochondria-endoplasmic reticulum (ER) interactions. Hypothalamic ER stress has emerged as a causative factor for the development of leptin resistance, but the underlying mechanisms are largely unknown. Here, we show that mitochondria-ER contacts in anorexigenic pro-opiomelanocortin (POMC) neurons in the hypothalamus are decreased in diet-induced obesity. POMC-specific ablation of Mfn2 resulted in loss of mitochondria-ER contacts, defective POMC processing, ER stress-induced leptin resistance, hyperphagia, reduced energy expenditure, and obesity. Pharmacological relieve of hypothalamic ER stress reversed these metabolic alterations. Our data establish MFN2 in POMC neurons as an essential regulator of systemic energy balance by fine-tuning the mitochondrial-ER axis homeostasis and function. This previously unrecognized role for MFN2 argues for a crucial involvement in mediating ER stress-induced leptin resistance. © 2013 Elsevier Inc.

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