Implication of Cx43 in hypothalamic detection of glucosis.

Meeting Abstract ; WOS: 000302819400014; International audience

Plasmalogens and cell‐cell communication between retinal glial cells

National audience; Purpose Plasmalogens are glycerophospholipids containing a vinyl‐ether bond at sn‐1 position of their glycerol backbone and polyunsaturated fatty acids (PUFAs) at sn‐2. We have previously shown that plasmalogens are involved in the regulation of perinatal retinal vascular development and particularly in astrocyte template formation (Saab et al, PLoSONE 2012 9(6):e101076). Since retinal Müller cells and astrocytes can communicate through calcium waves and connexin 43‐rich gap junctions, the aim of our study was to determine whether a reduction of plasmalogen levels affects communication between retinal glial cells. Methods Primary Müller cells and astrocyte were isolated f…

Gustatory evoked potentials activity and fatty taste

International audience; Introduction: Gustatory evoked potentials (GEP), detected in response to an intermittent stimulation of the gustatory receptors by a primary flavor, are a reliable and safe record of the human gustatory function. We previously highlighted the modifications of GEP in response to saccharose stimulation by the concentration of the saccharose solution and its hedonic sensation. Fatty taste might be considered as the sixth primary flavor. We aimed to demonstrate that GEP in response to fatty taste stimulation do exist, and to compare these GEP with the GEP in response to saccharose and salty taste.Methods: Healthy and voluntary male subjects were included. Each subject un…

Enhanced Hypothalamic Glucose Sensing in Obesity: Alteration of Redox Signalling

1939-327X (Electronic) Journal article; Objective : Recent data demonstrate that glucose sensing in different tissues is initiated by an intracellular redox-signaling pathway in physiological conditions. However, the relevance of such a mechanism in metabolic disease is not known. The aim of the present study was to determine whether brain-glucose hypersensitivity present in obese Zucker rat is related to an alteration in redox signaling. Research design and Methods: Brain glucose sensing alteration was investigated in vivo through the evaluation of electrical activity in arcuate nucleus, changes in ROS levels, and hypothalamic glucose-induced insulin secretion. In basal conditions, modific…

How hypothalamic mitochondria translate the energy status of the boby

Gustatory evoked cortical activity in humans in response to saccharose stimuli

National audience

Conférence

Modification des ingestions protéiques par la séance d’hémodialyse : une piste pour lutter contre la dénutrition

Introduction La denutrition proteino-energetique est un facteur de risque de mortalite chez les patients (P) en hemodialyse (HD). Le but de l’etude est de determiner si les apports alimentaires sont modifies par la seance d’HD et d’en rechercher d’eventuels mediateurs. Patients et methodes Un large choix d’aliments est propose a des P dialyses, non diabetiques, non fumeurs, sans comorbidite evolutive, 2 jours consecutifs a 12 heures apres l’HD et un jour sans HD. Les P choisissent la nature et la quantite d’aliments et leurs ingestions sont quantifiees. Des questionnaires avec echelle visuelle analogique permettent d’evaluer les criteres de choix des aliments. Les concentrations plasmatique…

Mitochondrial reactive oxygen species are obligatory signals for glucose-induced insulin secretion.

OBJECTIVE—Insulin secretion involves complex events in which the mitochondria play a pivotal role in the generation of signals that couple glucose detection to insulin secretion. Studies on the mitochondrial generation of reactive oxygen species (ROS) generally focus on chronic nutrient exposure. Here, we investigate whether transient mitochondrial ROS production linked to glucose-induced increased respiration might act as a signal for monitoring insulin secretion. RESEARCH DESIGN AND METHODS—ROS production in response to glucose was investigated in freshly isolated rat islets. ROS effects were studied using a pharmacological approach and calcium imaging. RESULTS—Transient glucose increase …

Evidence for hypothalamic ketone bodies sensing: impact on food intake and peripheral metabolic responses in mice

Monocarboxylates have been implicated in the control of energy homeostasis. Among them, the putative role of ketone bodies produced notably during high-fat diet (HFD) has not been thoroughly explored. In this study, we aimed to determine the impact of a specific rise in cerebral ketone bodies on food intake and energy homeostasis regulation. A carotid infusion of ketone bodies was performed on mice to stimulate sensitive brain areas for 6 or 12 h. At each time point, food intake and different markers of energy homeostasis were analyzed to reveal the consequences of cerebral increase in ketone body level detection. First, an increase in food intake appeared over a 12-h period of brain keton…

Effet chronique d’un édulcorant non nutritif – le sucralose - sur la détection hypothalamique du glucose chez le rat

Détection centrale de la glycémie et homéostasie énergétique

Venez découvrir le cerveau ! Au Centre des Sciences du Goût et de l'Alimentation à Dijon

Rencontrer des chercheurs qui travaillent sur le cerveau, chatouiller votre curiosité, échanger, poser des questions ?C'est ce que nous vous proposons lundi 13 et samedi 18 mars !Au travers de conférences (samedi), d'ateliers (lundi), les chercheurs vous proposent de mieux comprendre le cerveau.Tentez l'expérience !

0132 : Oxidative stress and cardio-metabolic alterations induced by postnatal programming can be reversed in adulthood by a short-term moderate caloric restriction

Postnatal overfeeding (PNOF) in rodents induces early programming of cardio-metabolic risk. Our aim was to determine if a moderate diet restriction could restore cardio-metabolic alterations induced by PNOF. Immediately after birth, litters of C57BL/6 mice were either maintained at 9 (normal litter, NL), or reduced to 3 (small litter, SL) to induce PNOF. At weaning, all mice received a standard diet ad libitum (AL). At 6 month of age, half of the NL and SL mice were assigned to a moderate 20% calorie restriction (CR: NLCR, SLCR) for one month, while the other mice continued to eat AL (AL: NLAL, SLAL). Glucose and insulin tolerance tests, cardiac function (echocardiography), body composition…

Semaine du Cerveau 2021 à Dijon : deux conférences en ligne du CSGA

" Ce que les illusions révèlent de notre cerveau visuel "Mardi 16/03, conférence de 12h30 à 13h30 :Dr. Arnaud LELEU, CNRS-INRAE-Université, Centre des Sciences du Goût et de l’Alimentation (CSGA), DijonLien vers la conférence sur Teams : https://bit.ly/38bSE6q" Quand notre cerveau co-nez ce qu'il voit : apprendre à voir avec les odeurs "Mercredi 17/03, conférence de 18h30 à 19h30Dr. Diane REKOW, CNRS-INRAE-Université, Centre des Sciences du Goût et de l’Alimentation, DijonLien vers la conférence sur Teams : https://bit.ly/3bhWD3e

Hypothalamic Apelin/Reactive Oxygen Species Signaling Controls Hepatic Glucose Metabolism in the Onset of Diabetes

Aims: We have previously demonstrated that central apelin is implicated in the control of peripheral glycemia, and its action depends on nutritional (fast versus fed) and physiological (normal versus diabetic) states. An intracerebroventricular (icv) injection of a high dose of apelin, similar to that observed in obese/diabetic mice, increase fasted glycemia, suggesting (i) that apelin contributes to the establishment of a diabetic state, and (ii) the existence of a hypothalamic to liver axis. Using pharmacological, genetic, and nutritional approaches, we aim at unraveling this system of regulation by identifying the hypothalamic molecular actors that trigger the apelin effect on liver gluc…

Détection cérébrale des nutriments et équilibre énergétique : cas du glucose

National audience

Extracts of moricandia for the use thereof in the prevention and treatment of metabolic diseases

La présente invention se rapporte à une composition comprenant un extrait de Moricandia, pour son utilisation dans la prévention et/ou le traitement des maladies cardiométaboliques. Elle se rapporte aussi à un alicament comprenant un extrait de Moricandia, ainsi qu'à des méthodes de prévention de la prise de poids, notamment de masse grasse.

Role for mitochondrial reactive oxygen species in brain lipid sensing: redox regulation of food intake.

0012-1797 (Print) Journal Article Research Support, Non-U.S. Gov't; The ability for the brain to sense peripheral fuel availability is mainly accomplished within the hypothalamus, which detects ongoing systemic nutrients and adjusts food intake and peripheral metabolism as needed. Here, we hypothesized that mitochondrial reactive oxygen species (ROS) could trigger sensing of nutrients within the hypothalamus. For this purpose, we induced acute hypertriglyceridemia in rats and examined the function of mitochondria in the hypothalamus. Hypertriglyceridemia led to a rapid increase in the mitochondrial respiration in the ventral hypothalamus together with a transient production of ROS. Cerebral…

Hypothalamic Astroglial Connexins are Required for Brain Glucose Sensing-Induced Insulin Secretion

Supplementary Information accompanies the paper on the Journal of Cerebral Blood Flow & Metabolism website; Hypothalamic glucose detection participates in maintaining glycemic balance, food intake, and thermogenesis. Although hypothalamic neurons are the executive cells involved in these responses, there is increasing evidence that astrocytes participate in glucose sensing (GS); however, it is unknown whether astroglial networking is required for glucose sensitivity. Astroglial connexins 30 and 43 (Cx30 and Cx43) form hexameric channels, which are apposed in gap junctions, allowing for the intercellular transfer of small molecules such as glucose throughout the astroglial networks. Here, we…

Sucralose and acesulfame K modulate human and rodent vascular smooth muscle contractility independently of the presence of the sweet taste receptor. A study of the SOSweet project

Taste of Fat and Obesity: Different Hypotheses and Our Point of View

Obesity results from a temporary or prolonged positive energy balance due to an alteration in the homeostatic feedback of energy balance. Food, with its discriminative and hedonic qualities, is a key element of reward-based energy intake. An alteration in the brain reward system for highly palatable energy-rich foods, comprised of fat and carbohydrates, could be one of the main factors involved in the development of obesity by increasing the attractiveness and consumption of fat-rich foods. This would induce, in turn, a decrease in the taste of fat. A better understanding of the altered reward system in obesity may open the door to a new era for the diagnosis, management and treatment of th…

Importance of mitochondrial dynamin-related protein 1 in hypothalamic glucose sensitivity in rats.

International audience; AIMS: Hypothalamic mitochondrial reactive oxygen species (mROS)-mediated signaling has been recently shown to be involved in the regulation of energy homeostasis. However, the upstream signals that control this mechanism have not yet been determined. Here, we hypothesize that glucose-induced mitochondrial fission plays a significant role in mROS-dependent hypothalamic glucose sensing. RESULTS: Glucose-triggered translocation of the fission protein dynamin-related protein 1 (DRP1) to mitochondria was first investigated in vivo in hypothalamus. Thus, we show that intracarotid glucose injection induces the recruitment of DRP1 to VMH mitochondria in vivo. Then, expressio…

Hypothalamic reactive oxygen species are required for insulin-induced food intake inhibition: an NADPH oxidase-dependent mechanism

1939-327X (Electronic) Journal Article Research Support, Non-U.S. Gov't; OBJECTIVE: Insulin plays an important role in the hypothalamic control of energy balance, especially by reducing food intake. Emerging data point to a pivotal role of reactive oxygen species (ROS) in energy homeostasis regulation, but their involvement in the anorexigenic effect of insulin is unknown. Furthermore, ROS signal derived from NADPH oxidase activation is required for physiological insulin effects in peripheral cells. In this study, we investigated the involvement of hypothalamic ROS and NADPH oxidase in the feeding behavior regulation by insulin. RESEARCH DESIGN AND METHODS: We first measured hypothalamic RO…

potentiels évoqués gustatifs chez l'Homme en réponse à une stimulation sucrée

International audience

Alteration of hypothalamic glucose and lactate sensing in 48h hyperglycemic rats.

International audience; Hypothalamic detection of nutrients is involved in the control of energy metabolism and is altered in metabolic disorders. Although hypothalamic detection of blood lactate lowers hepatic glucose production and food intake, it is unknown whether it also modulates insulin secretion. To address this, a lactate injection via the right carotid artery (cephalad) was performed in Wistar rats. This triggered a transient increase in insulin secretion. Rats made hyperglycemic for 48h exhibited prolonged insulin secretion in response to a glucose injection via the carotid artery, but lactate injection induced two types of responses: half of the HG rats showed no difference comp…

Transient Receptor Potential Canonical 3 (TRPC3) Channels Are Required for Hypothalamic Glucose Detection and Energy Homeostasis

Fil: Chrétien, Chloé. University of Bourgogne Franche-Comté. Institut National de la Recherche Agronomique. Centre des Sciences du Goût et de l’Alimentation; France Fil: Fenech, Claire. University of Bourgogne Franche-Comté. Institut National de la Recherche Agronomique. Centre des Sciences du Goût et de l’Alimentation; France Fil: Liénard, Fabienne. University of Bourgogne Franche-Comté. Institut National de la Recherche Agronomique. Centre des Sciences du Goût et de l’Alimentation; France Fil: Grall, Sylvie. University of Bourgogne Franche-Comté. Institut National de la Recherche Agronomique. Centre des Sciences du Goût et de l’Alimentation; France Fil: Chevalier, Charlène. University of …

Gustatory evoked potentials and cerebral control of food intake in obese subjects (PEGASE study)

Cortical taste activity in response to sucrose and sweeteners solutions: a study using gustatory evoked potential

Introduction: Sweeteners are widespread in overweight or diabetic patients because of their high sweetening power and their light effect on glycaemia. Sweeteners effects on cortical activity, reflecting both cortical analysis and gustatory signalization pathway, are not well known. We observed previously that gustatory evoked potentials (GEPs) in response to sucrose varied in latency and/or in amplitude with sucrose concentration of the solution, the pleasantness of taste and the feeding status. The aim was to compare the gustatory cortical activity by recording GEPs in response to sucrose, aspartame and stevia solutions.Methods: Twenty healthy non-smoker adult volunteers were included (mea…

Détection hypothalamique du glucose et homéostasie énergétique

Prestation et revue; Détection hypothalamique du glucose et homéostasie énergétique. JFN 2018, Journées Francophones de Nutrition

Haemodialysis in patients with chronic renal failure increases the wanting for foods rich in proteins

Haemodialysis in patients with chronic renal failure increases the wanting for foods rich in proteins. 24. Annual Meeting of the European-Chemoreception-Research-Organization (ECRO)

Short-term moderate diet restriction in adulthood can reverse oxidative, cardiovascular and metabolic alterations induced by postnatal overfeeding in mice

AbstractWe aimed to determine whether moderate diet restriction could restore cardiac, oxidative and metabolic alterations induced by postnatal overfeeding (PNOF). Litters of C57BL/6 male mice were either maintained at 9 (normal litter, NL), or reduced to 3 (small litter, SL) in order to induce PNOF. At 6 months, half of the NL and SL mice were subjected to 20% calorie-restriction (CR: NLCR, SLCR) for one month, while the other half continued to eat ad libitum (AL: NLAL, SLAL). Six-month old SL mice presented overweight, fat accumulation, hyperleptinemia, glucose intolerance, insulin resistance, increased cardiac ROS production and decreased left ventricular ejection fraction (LVEF). After …

Method for functional study of mitochondria in rat hypothalamus

1872-678X (Electronic) Journal Article Research Support, Non-U.S. Gov't; Different roles of mitochondria in brain function according to brain area are now clearly emerging. Unfortunately, no technique is yet described to investigate mitochondria function in specific brain area. In this article, we provide a complete description of a procedure to analyze the mitochondrial function in rat brain biopsies. Our two-step method consists in a saponin permeabilization of fresh brain tissues in combination with high-resolution respirometry to acquire the integrated respiratory rate of the biopsy. In the first part, we carefully checked the mitochondria integrity after permeabilization, defined exper…

Glucose and hypothalamic astrocytes: More than a fueling role?

Brain plays a central role in energy homeostasis continuously integrating numerous peripheral signals such as circulating nutrients, and in particular blood glucose level, a variable that must be highly regulated. Then, the brain orchestrates adaptive responses to modulate food intake and peripheral organs activity in order to achieve the fine tuning of glycemia. More than fifty years ago, the presence of glucose-sensitive neurons was discovered in the hypothalamus, but what makes them specific and identifiable still remains disconnected from their electrophysiological signature. On the other hand, astrocytes represent the major class of macroglial cells and are now recognized to support an…

Glucose-induced mitochondrial fission through DRP1 is required for redox signaling in hypothalamic glucose sensing mechanism

Communication affichée; We previously showed that hypothalamic glucose sensing requires a redox signaling in hypothalamic arcuate nucleus, through glucose‐induced mitochondrial H2O2 production (1). ROS implication in nutrient sensing has been confirmed by others studies (2). Recent studies highlight mitochondrial morphology changes under glycemia increase, which depends on mitochondrial dynamics. Changes in mitochondrial dynamics are causative events in mitochondrial reactive oxygen species (mROS) production when glycemia rises. It has been demonstrates that mitochondrial fission blockade decreases mROS production during hyperglycemia in metabolic‐sensitive cells, such as hepatocytes or myo…