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The role of microbiota in eating disorders has recently emerged. Previous data reported that lipopolysaccharides induce anorexia and a decrease of body weight through the activation of toll-like receptor 4 (TLR4). In the activity-based anorexia (ABA) mouse model, an increase of TLR4 expression in intestinal epithelial cells (IEC) has been described. We thus aimed to characterize the role of TLR4 in IEC in the ABA model in male and female mice. For this purpose, Vill-CreERT2-TLR4 LoxP, which are depleted for TLR4 in IEC in response to 4-OH tamoxifen, were submitted (ABA) or not (CT) to the ABA procedure that combined free access to a running wheel and progressive time-limited access to food. We thus compared CT and ABA TLR4IEC−/− mice to CT and ABA TLR4IEC+/+ mice. In response to the ABA model, TLR4IEC+/+ male and female mice exhibited a body weight loss associated to a decrease of lean mass. In TLR4IEC−/− male mice, body weight loss was delayed and less pronounced compared to TLR4IEC+/+ male mice. We did not observe a difference of body weight loss in female mice. The body composition remained unchanged between TLR4IEC−/− and TLR4IEC+/+ mice in both sexes. In both sexes, ABA TLR4IEC+/+ mice exhibited an increase of food-anticipatory activity, as well as an increase of immobility time during the open field test. However, female TLR4IEC−/− mice showed a decrease of the time spent at the centre and an increase of the time spent at the periphery of the open field area, whereas we did not observe differences in the male mice. In conclusion, the invalidation of TLR4 in IEC modified the response to the ABA model in a sex-dependent manner. Further studies should decipher the underlying mechanisms.

Summary Background & aims Anorexia nervosa (AN) is a severe psychological and potentially life-threatening eating disorder. The activity-based anorexia (ABA) mouse model is commonly used to investigate physiological abnormalities associated with this disorder. Characterizing the holistic biochemical alterations induced by anorexia is essential to understanding AN pathophysiology as well as to define biomarkers for prognosis. Methods To unravel the adaptive biochemical mechanisms occurring in this model in response to self-starvation, the urinary, plasma and fecal metabolic phenotypes of mice under different experimental conditions were compared. This included control mice with and without physical activity (CT and CTPA mice), a group with limited food access (LFA), and a group with both limited food access and physical activity (ABA). Using 1H nuclear magnetic resonance (NMR) spectroscopy, several biochemical perturbations were observed. Results Physical activity altered the abundance of 14 fecal metabolites, including those involved in gut microbial metabolism and proteolysis. Food restriction disrupted a wide range of metabolic pathways including gut microbial metabolism, proteolysis and fatty acid breakdown (24 urinary and 6 plasma metabolites). The combined impact of food restriction and physical activity resulted in the same pattern of metabolic disruption (24 urine, 6 plasma). Conclusions This work defined the metabolic signatures of ABA mice and provides novel insights into biological adaptations of mice in response to both food restriction and physical activity. These results should be further confirmed in AN patients.

Pre-pubertal murine models of acute colitis are lacking. Magnetic resonance colonography (MRC) is a promising minimally invasive tool to assess colitis. We aimed to: 1/ Adapt a model of acute experimental colitis to pre-pubertal rats and determine whether MRC characteristics correlate with histological inflammation. 2/ Test this model by administering a diet supplemented in transforming growth factor β2 to reverse inflammation. Twenty-four rats were randomized at weaning to one of 3 groups: Trinitrobenzene Sulfonic Acid (TNBS) group (n = 8) fed a standard diet, that received an intra-rectal 60 mg/kg dose of TNBS-ethanol; Control group (n = 8) fed standard diet, that received a dose of intra-rectal PBS; TNBS+MODULEN group (n = 8) that received a dose of TNBS and were exclusively fed MODULEN-IBD® after induction of colitis. One week after induction of colitis, rats were assessed by MRC, colon histopathology and inflammation markers (Interleukin 1β, Tumor necrosis factor α, Nitric Oxide Synthase 2 and Cyclooxygenase 2). TNBS induced typical features of acute colitis on histopathology and MRC (increased colon wall thickness, increased colon intensity on T2-weighted images, target sign, ulcers). Treatment with MODULEN-IBD® did not reduce signs of colitis on MRC. Inflammatory marker expression did not differ among study groups.

Intestinal fibrosis is a frequent complication in inflammatory bowel diseases (IBD). It is a challenge to identify environmental factors such as diet that may be driving this risk. Intestinal fibrosis result from accumulation of extracellular matrix (ECM) proteins secreted by myofibroblasts. Factors promoting intestinal fibrosis are unknown, but diet appears to be a critical component in its development. Consumption of salt above nutritional recommendations can exacerbate chronic inflammation. So far, high salt diet (HSD) have not been thoroughly investigated in the context of intestinal fibrosis associated to IBD. In the present study, we analyze the role of dietary salt in TNBS chronic colitis induced in rat, an intestinal fibrosis model, or in human colon fibroblast cells. Here, we have shown that high-salt diet exacerbates undernutrition and promoted ECM-associated proteins in fibroblasts. Taken together, our results suggested that dietary salt can activate intestinal fibroblasts, thereby contributing to exacerbation of intestinal fibrosis. Dietary salt may be considered as a putative environmental factor that drives intestinal fibrosis risk.

Summary Background & aims In the last decade, the role of the microbiota–gut–brain axis in eating behavior and anxiety-depressive disorders has gained increasing attention. Although a gut microbiota dysbiosis has been reported in anorectic patients, its pathophysiological role remains poorly understood. Thus, we aimed to characterize the potential role of gut microbiota by evaluating the effects of its depletion in the Activity-Based Anorexia (ABA) mouse model both in male and female mice. Methods Male and female C57Bl/6 mice were submitted (ABA group) or not (CT group) to the ABA protocol, which combines access to a running wheel with a progressive limited food access. Gut microbiota was previously depleted or not by a cocktail of antibiotics (ATB) delivered by oral gavages. We monitored body composition, anxiety-like behavior, leptin and adiponectin plasma levels, hypothalamic and hippocampal neuropeptides mRNA levels, as well as dopamine (DRD) and serotonin (5HT1 and 4) receptors mRNA expression. Results In response to the ABA model, the body weight loss was less pronounced in ATB-treated ABA compared to untreated ABA, while food intake remained unaffected by ATB treatment. ATB-treated ABA exhibited increased fat mass and decreased lean mass compared to untreated ABA both in male and female mice, whereas but plasma adipokine concentrations were affected in a sex-dependent manner. Only male ABA mice showed a reduced anticipatory physical activity in response to ATB treatment. Similarly, anxiety-like behavior was mainly affected in ATB-treated ABA male mice compared to ATB-treated ABA female mice, which was associated with male-specific alterations of hypothalamic CRH mRNA and hippocampal DRD and 5-HT1A mRNA levels. Conclusions Our study provides evidence that ATB-induced gut microbiota depletion triggers alterations of nutritional and behavioral responses to the activity-based anorexia model in a sex-dependent manner.

Background: Optimizing the refeeding of patients with anorexia nervosa remains important to limit somatic complications of malnutrition, as well as to avoid disease relapses by targeting persistent mood and intestinal disorders. We aimed to evaluate the effects of glutamine (Gln) and branched-chain amino acids (BCAA) supplementation during refeeding in activity-based anorectic (ABA) mice. Method: Male C57Bl/6 mice were randomized in control and ABA groups. Once ABA-induced malnutrition was established, mice were progressively refed or not. Refed mice had free access to drinking water supplemented or not with 1% Gln or 2.5% BCAA for 10 days. Results: A progressive refeeding was associated with a partial restoration of body weight and lean mass, while a fat mass rebound was observed. In addition, refeeding restored glucose and leptin. Gln did not affect these parameters, while BCAA tended to increase body weight, fat mass, and glycaemia. In the colon, refeeding improved total protein synthesis and restored the LC3II/LC3I ratio, a marker of autophagy. Gln supplementation enhanced colonic protein synthesis, which was associated with an increased p-p70S6kinase/p70S6kinase ratio, whereas these effects were blunted by BCCA supplementation. Conclusions: In ABA mice, Gln and BCAA supplementations during a progressive refeeding fail to restore body weight and lean mass. However, Gln supplementation improves total colonic protein synthesis conversely to BCAA. Further studies are needed to decipher the underlying mechanisms involved in these opposite results.

Introduction et but de l’etude Les patients atteints d’anorexie mentale souffrent regulierement de troubles intestinaux persistants lors de la renutrition, ce qui peut etre un frein a leur prise en charge nutritionnelle. Le but de cette etude etait d’evaluer si la renutrition associee ou non a une supplementation en glutamine (Gln) ou en acides amines branches (BCAA) pouvait ameliorer les fonctions gastro-intestinales dans le modele murin activity-based anorexia (ABA). Materiel et methodes Quatre-vingt-huit souris mâles C57Bl/6 âgees de huit semaines ont ete placees dans des cages individuelles et randomisees en groupes controle (CTRL) et ABA. Les souris ABA avaient un acces libre a une roue d’activite. Apres cinq jours d’adaptation, l’acces a la nourriture a ete progressivement limite pour atteindre 3 heures au jour 9. Au jour 14, les animaux ABA ont ete randomises en differents sous-groupes : non-renourri (ABA-C), renourri (ABA-Rf), renourri supplemente en Gln (ABA-Rf-G) ou en BCAA (ABA-Rf-B). La renutrition consistait a augmenter la quantite de nourriture de 0,5 g/jour, a partir de 2,5 g au jour 14, pour atteindre 5 g. La Gln et les BCAA (Leu, Ile, Val) etaient distribues dans l’eau de boisson, a la concentration de 1 % et 2,5 % respectivement. La composition corporelle, la permeabilite intestinale et la vidange gastrique ont ete mesurees. Les resultats ont ete analyses en ANOVA-1 voie et p Resultats et analyse statistique Le poids et la masse maigre ont ete partiellement restaures par la renutrition (p Conclusion La renutrition a permis de restaurer la vitesse de vidange gastrique. La Gln, mais pas les BCAA, a potentialise les effets benefiques de la renutrition dans le colon notamment en augmentant l’expression des proteines de jonction serrees et la synthese proteique totale.

International audience; Anorexia nervosa is a severe eating disorder often associated with physical hyperactivity and is more frequently observed in female sex. Activity-Based Anorexia (ABA) model combines physical activity (PA) and reduced food intake and thus allows a better understanding of the mechanisms underlying anorexia nervosa. We aimed to assess sex differences in response to ABA model in C57Bl/6 mice. Twenty four male and 16 female C57BL/6 mice were studied. ABA mice were placed in individual cages with a continuously recorded activity wheel. ABA mice had a progressive limited food access from 6 h/day (day 6) to 3 h/day (day 9) until the end of the protocol (day 17). Body weight and food intake were daily measured. We studied physical activity during 24 h, during the dark phase (D-PA) and the light phase (L-PA). We also evaluated the feeding anticipatory physical activity (A-PA), the physical activity during food intake period (FI-PA) and the post-prandial physical activity (PP-PA). We observed 16.7% of mortality in males (4 out of 24 mice) during ABA protocol while no female mice died (p = 0.09). At day 17, food intake was significantly higher in females than in males (p < 0.05) that was associated with a lower body weight loss than in females (p < 0.05). Before limited food access, no gender differences in wheel running activity were observed. From day 9, A-PA significantly increased over time in males (p < 0.05 vs females) while females exhibited higher FI-PA and PP-PA (p < 0.05 vs males). Correlations between wheel running activities and, respectively, food intake and body weight loss showed gender differences, in particularly for L-PA and A-PA. Our results suggest a greater susceptibility of male mice to develop ABA, males and females exhibit different patterns of physical activity after limitation of food access. Underlying mechanisms should be further investigated.

Introduction et but de l’etude Au cours de l’anorexie mentale, un trouble du comportement alimentaire caracterise par un poids corporel faible, la renutrition est frequemment associee a un rebond de masse grasse et n’ameliore qu’en partie les troubles fonctionnels digestifs (TFD) frequemment observes, qui sont un frein a la renutrition. Dans differents modeles, la glutamine (Gln) limite les TFD et les acides amines branches (BCAA) augmentent la masse maigre. Cette etude avait pour but d’evaluer les effets d’une supplementation en Gln ou en BCAA au cours d’une renutrition progressive dans le modele activity-based anorexia (ABA). Materiel et methodes Quarante-huit souris mâles C57Bl/6 ont ete placees dans des cages individuelles et reparties en deux groupes : Controle (Ct ; n = 16) et ABA (n = 32). Apres 5 jours, l’acces a la nourriture dans le groupe ABA a ete progressivement reduit de 6 h/jour au jour 6 a 3 h/jour au jour 9. Au jour 14, les animaux ABA ont ete repartis en 4 groupes : non renourri (ABA-C), renourri (ABA-Rf), renourri et supplemente en Gln (ABA-G) ou acides amines branches (ABA-B). La renutrition consistait en une augmentation progressive (0,5 g/jour) de la quantite de nourriture jusqu’a atteindre 5 g/jour. Les acides amines etaient apportes dans l’eau de boisson. Le poids, la composition corporelle, la permeabilite colique, la synthese proteique musculaire (soleus) et colique, les voies de signalisation et des parametres metaboliques plasmatiques ont ete mesures. Resultats et analyse statistique A la fin du protocole (jour 23), le poids (g) des groupes ABA-Rf (22,4 ± 0,3), ABA-G (22,7 ± 0,2) et ABA-B (23,5 ± 0,3) etait significativement superieur au groupe ABA-C (19,2 ± 0,2 ; p Conclusion En conclusion, lors d’une renutrition progressive dans le modele ABA, la supplementation en BCAA favoriserait la reprise de poids, mais plutot en faveur de la masse grasse alors qu’une supplementation en Gln est associee a une restauration de la synthese proteique colique par l’activation de la voie mTOR.

Obesity and irritable bowel syndrome (IBS) are two major public health issues. Interestingly previous data report a marked increase of IBS prevalence in morbid obese subjects compared with non-obese subjects but underlying mechanisms remain unknown. Obesity and IBS share common intestinal pathophysiological mechanisms such as gut dysbiosis, intestinal hyperpermeability and low-grade inflammatory response. We thus aimed to evaluate the link between obesity and IBS using different animal models. Male C57Bl/6 mice received high fat diet (HFD) for 12 weeks and were then submitted to water avoidance stress (WAS). In response to WAS, HFD mice exhibited higher intestinal permeability and plasma corticosterone concentration than non-obese mice. We were not able to reproduce a similar response both in ob/ob mice and in leptin-treated non-obese mice. In addition, metformin, a hypoglycemic agent, limited fasting glycaemia both in unstressed and WAS diet-induced obese mice but only partially restored colonic permeability in unstressed HFD mice. Metformin failed to improve intestinal permeability in WAS HFD mice. Finally, cecal microbiota transplantation from HFD mice in antibiotics-treated recipient mice did not reproduce the effects observed in stressed HFD mice. In conclusion, stress induced a more marked intestinal barrier dysfunction in diet-induced obese mice compared with non-obese mice that seems to be independent of leptin, glycaemia and gut microbiota. These data should be further confirmed and the role of the dietary composition should be studied.

Anorexia nervosa (AN) is a severe psychological and potentially life-threatening eating disorder. The activity-based anorexia (ABA) mouse model is commonly used to investigate physiological abnormalities associated with this disorder. Characterizing the holistic biochemical alterations induced by anorexia is essential to understanding AN pathophysiology as well as to define biomarkers for prognosis.To unravel the adaptive biochemical mechanisms occurring in this model in response to self-starvation, the urinary, plasma and fecal metabolic phenotypes of mice under different experimental conditions were compared. This included control mice with and without physical activity (CT and CTPA mice), a group with limited food access (LFA), and a group with both limited food access and physical activity (ABA). UsingPhysical activity altered the abundance of 14 fecal metabolites, including those involved in gut microbial metabolism and proteolysis. Food restriction disrupted a wide range of metabolic pathways including gut microbial metabolism, proteolysis and fatty acid breakdown (24 urinary and 6 plasma metabolites). The combined impact of food restriction and physical activity resulted in the same pattern of metabolic disruption (24 urine, 6 plasma).This work defined the metabolic signatures of ABA mice and provides novel insights into biological adaptations of mice in response to both food restriction and physical activity. These results should be further confirmed in AN patients.

Background: During activity-based anorexia (ABA) in mice, enhanced paracellular permeability and reduced protein synthesis have been shown in the colon while the gut&ndash, brain axis has received increasing attention in the regulation of intestinal and mood disorders that frequently occur during anorexia nervosa, a severe eating disorder for which there is no specific treatment. In the present study, we assessed the effects of oral glutamine (Gln) or branched-chain amino acids (BCAA) supplementation during ABA to target intestinal functions, body composition and feeding behavior. Methods: C57BL/6 male mice were randomized in Control (CTRL) and ABA groups. After ABA induction, mice received, or not, either 1% Gln or 2.5% BCAA (Leu, Ile, Val) for one week in drinking water. Results: Neither Gln nor BCAA supplementation affected body weight and body composition, while only Gln supplementation slightly increased food intake. ABA mice exhibited increased paracellular permeability and reduced protein synthesis in the colonic mucosa. Oral Gln restored colonic paracellular permeability and protein synthesis and increased the mucin-2 mRNA level, whereas BCAA did not affect colonic parameters. Conclusion: In conclusion, oral Gln specifically improves colonic response during ABA. These data should be further confirmed in AN patients.

Introduction et but de l’etude L’anorexie mentale est une pathologie a predominance feminine pour des raisons qui restent encore peu connues. L’axe microbiote-intestin-cerveau semble contribuer a la physiopathologie de l’Anorexie. Le but de cette etude etait de comparer la reponse metabolique et comportementale a une depletion du microbiote intestinal dans un modele murin d’anorexie lie a une activite physique (Activity-Based Anorexia ; ABA) chez des souris mâles et femelles. Materiel et methodes De J1 a J18, des souris C57Bl/6 mâles et femelles ont ete soumises au modele ABA combinant un acces libre a une roue d’activite et une limitation progressive de l’acces a la nourriture. Les animaux controles (CT) avaient un acces libre a la nourriture sans roue d’activite. Le microbiote intestinal a ete deplete par gavage antibiotiques et antifongique de J-9 a J17 (ATB). Au cours du modele ABA, le poids et la composition corporelle ont ete mesures. Des tests d’anxiete (Open Field) ont egalement ete effectues. La permeabilite intestinale ainsi que les taux des ARNm codant pour les neuropeptides impliques dans la regulation de la prise alimentaire au niveau hypothalamique et hippocampique ont ete analyses. Resultats et analyse statistique La depletion du microbiote intestinal seule n’entraine pas de modifications de poids corporel chez les souris mâles et femelles mais est associee a une augmentation de masse grasse (+22 % et +94 %, respectivement) et une diminution de masse maigre (−11 % et −14 %, respectivement). En reponse au modele ABA, la perte de poids etait moins marquee chez les souris mâles ABA + ATB par rapport aux ABA (−10,0 ± 1,7 % vs −15,0 ± 1,6 %, p Conclusion La depletion du microbiote intestinal seule est associee a une modification de la composition corporelle avec un profil similaire chez les souris mâles et femelles. En revanche, au cours du modele ABA, la depletion du microbiote intestinal induit une reponse sexe-dependante, concernant le poids, la permeabilite intestinale, l’anxiete et la reponse centrale, dont les mecanismes restent a etudier.

Introduction et but de l’etude La prevalence du syndrome de l’intestin irritable (SII) est augmentee chez des patients en obesite massive [1] . Or, ces deux pathologies, qui sont des enjeux majeurs de sante publique, partagent des mecanismes physiopathologiques intestinaux communs telles que : une dysbiose intestinale, une hyperpermeabilite intestinale et une micro-inflammation intestinale. Le but de cette etude etait donc de chercher a comprendre les mecanismes mis en jeu dans les interactions obesite et SII chez la souris. Materiel et methodes Des souris mâles C57Bl/6, âgees de 8 semaines, ont recu une alimentation standard (SD) ou riche en graisses (60 % de kcal sous forme lipidique, HFD) pendant 12 semaines, puis ont ete soumises a un stress du a l’evitement de l’eau (WAS), 1 heure par jour pendant 10 jours. Des souris genetiquement obeses ob/ob ont egalement ete soumises au WAS. Resultats et analyse statistique Les souris HFD et ob/ob presentent une intolerance au glucose (267,7 ± 11,2 et 261,4 ± 12,4 vs 206,1 ± 5,3 AUC ; p Conclusion En conclusion, le stress induit un dysfonctionnement de la barriere intestinale plus marque chez les souris rendues obeses par une alimentation riche en graisse comparativement aux souris non obeses. Cet effet semble etre independant de la voie de la leptine, de l’hyperglycemie et n’implique pas le microbiote intestinal. Le role des composants de l’alimentation riche en lipides reste a evaluer.

Restrictive anorexia nervosa is associated with reduced eating and severe body weight loss leading to a cachectic state. Hypothalamus plays a major role in the regulation of food intake and energy homeostasis. In the present study, alterations of hypothalamic proteome and particularly of proteins involved in energy and mitochondrial metabolism have been observed in female activity-based anorexia (ABA) mice that exhibited a reduced food intake and a severe weight loss. In the hypothalamus, mitochondrial dynamic was also modified during ABA with an increase of fission without modification of fusion. In addition, increased dynamin-1, and LC3II/LC3I ratio signed an activation of autophagy while protein synthesis was increased. In conclusion, proteomic analysis revealed an adaptive hypothalamic protein response in ABA female mice with both altered mitochondrial response and activated autophagy.

A role for immunoproteasome in the regulation of intestinal permeability has been previously suggested both in mice during water avoidance stress (WAS) and in patients with irritable bowel syndrome (IBS). Here, we provide evidence that the ubiquitin-proteasome system (UPS) contributes to the pathophysiology of IBS. Indeed, we report that colonic proteome is altered in WAS mice and that β2i subunit deficiency modifies the proteome response that is associated with a limitation of colonic hyperpermeability. Interestingly, we show specific alterations of proteins involved in UPS, mitochondrial, and energy metabolism. We also report changes in the pattern of colonic ubiquitome in diarrhea-predominant IBS (IBS-D) patients and particularly a reduced expression of ubiquitinated proteins involved in the nuclear factor-kappa B (NF-κB) inflammatory signaling pathway. All these data suggest that immunoproteasome targeting may represent a new therapeutic strategy for the treatment of IBS patients with increased intestinal permeability.

Anorexia nervosa is an eating disorder often associated with intestinal disorders. To explore the underlying mechanisms of these disorders, the colonic proteome was evaluated during activity-based anorexia. Female C57Bl/6 mice were randomized into three groups: Control, Limited Food Access (LFA) and Activity-Based Anorexia (ABA). LFA and ABA mice had a progressive limited access to food but only ABA mice had access to an activity wheel. On colonic mucosal protein extracts, a 2D PAGE-based comparative proteomic analysis was then performed and differentially expressed proteins were identified by LC-ESI-MS/MS. Twenty-seven nonredundant proteins that were differentially expressed between Control, LFA, and ABA groups were identified. ABA mice exhibited alteration of several mitochondrial proteins involved in energy metabolism such as dihydrolipoyl dehydrogenase and 3-mercaptopyruvate sulfurtransferase. In addition, a downregulation of mammalian target of rapamycin (mTOR) pathway was observed leading, on the one hand, to the inhibition of protein synthesis, evaluated by puromycin incorporation and mediated by the increased phosphorylation of eukaryotic elongation factor 2, and on the other hand, to the activation of autophagy, assessed by the increase of the marker of autophagy, form LC3-phosphatidylethanolamine conjugate/Cytosolic form of Microtubule-associated protein 1A/1B light chain 3 (LC3II/LC3I) ratio. Colonic mucosal proteome is altered during ABA suggesting a downregulation of energy metabolism. A decrease of protein synthesis and an activation of autophagy were also observed mediated by mTOR pathway.

Ubiquitin proteasome system contributes to the regulation of intestinal inflammatory response as its inhibition is associated with tissue damage improvement. We aimed to evaluate whether glutamine is able to limit inflammation by targeting ubiquitin proteasome system in experimental colitis. Colitis was induced in male rats by intrarectal instillation of 2-4-6-trinitrobenzen sulfonic acid (TNBS) at day 1. From day 2 to day 6, rats daily received either an intrarectal instillation of PBS (TNBS/PBS group) or glutamine (TNBS/Gln). Rats were euthanized at day 7 and colonic samples were taken to evaluate ubiqutinated proteins by proteomic approach combining 2D electrophoresis and immunoblots directed against ubiquitin. Results were then confirmed by evaluating total expression of proteins and mRNA levels. Survival rate, TNFα, and IL-1β mRNA were improved in TNBS/Gln compared with TNBS/PBS (p < 0.05). Proteasome activities were affected by TNBS but not by glutamine. We identified eight proteins that were less ubiquitinated in TNBS/PBS compared with controls with no effect of glutamine. Four proteins were more ubiquitinated in TNBS/PBS group and restored in TNBS/Gln group. Finally, 12 ubiquitinated proteins were only affected by glutamine. Among proteins affected by glutamine, eight proteins (GFPT1, Gapdh, Pkm2, LDH, Bcat2, ATP5a1, Vdac1, and Vdac2) were involved in metabolic pathways. In conclusion, glutamine may regulate ubiquitination process during intestinal inflammation.

Introduction et but de l’etude L’anorexie mentale (AM), trouble du comportement alimentaire restrictif souvent associe a une activite physique intense, entraine un etat de denutrition chronique severe. Le modele « activity-based anorexia » (ABA) est frequemment utilise pour etudier la physiopathologie de l’AM avec une duree d’etude allant de 3 a 11 jours de reduction des apports alimentaires. Le but de notre etude etait d’evaluer la reponse au modele ABA sur une periode prolongee jusqu’a 20 jours. Materiel et methodes Des souris mâles C57BL/6 ont ete placees dans des cages individuelles avec ou sans roue d’activite. Apres 5 jours d’adaptation, l’acces a la nourriture a ete progressivement reduit pour arriver a 3 heures d’acces au jour 9. Les animaux ont ete repartis en 3 groupes : Controle (CTRL ; pas de restriction et pas de roue d’activite), Limited Food Access (LFA ; restriction sans roue d’activite) et ABA (restriction + roue d’activite). Deux series d’animaux ont ete menees avec un sacrifice des souris au jour 17 (j17) ou au jour 25 (j25, n = 8/groupe/temps). Un suivi quotidien a ete realise, ainsi qu’une mesure de la composition corporelle par EchoMRI. Enfin les taux des ARNm codant pour NPY et POMC ont ete mesures par RT-qPCR au niveau hypothalamique. Resultats et analyse statistique A j17, la perte de poids etait plus importante pour le groupe ABA (−27,5 ± 0,02 %) que pour le groupe LFA (−17,7 ± 0,01 %, p Conclusion Le modele ABA est associe a une denutrition proteique persistante au jour 25 (diminution de masse maigre), associee a une restauration de la masse grasse probablement secondaire a une legere augmentation de la prise alimentaire. Ces resultats incitent a favoriser des approches therapeutiques favorisant le gain de masse maigre lors de la renutrition.

Introduction et but de l’etude L’anorexie mentale est un trouble du comportement alimentaire associe a un etat de denutrition chronique severe avec une perte de masse grasse et de masse maigre et des adaptations metaboliques. Afin de mieux comprendre la regulation de l’homeostasie proteique au cours de l’anorexie, nous avons etudie le metabolisme proteique dans differents tissus au cours du modele d’anorexie associee a une activite physique (ABA) chez la souris. Materiel et methodes Des souris femelles C57Bl/6 ont ete placees dans des cages avec (ABA, n = 8) ou sans roue d’activite (Controles, CT – n = 8 ; acces limite a l’alimentation, LFA – n = 8). Les groupes ABA et LFA avaient un acces progressivement limite a l’alimentation de 6 h/j au jour 6 a 3 h/j au jour 9. Le protocole etait poursuivi jusqu’au jour 17. Un suivi quotidien des animaux a ete realise (poids, prise alimentaire et hydrique, activite physique). Au jour 17, vingt minutes avant l’euthanasie, une injection intraveineuse de puromycine a ete realisee afin d’evaluer la synthese proteique dans differents tissus (hypothalamus, estomac, colon, foie, muscle soleaire et tibialis anterieur) par la methode SUnSET. Enfin, le rapport LC3II/LC3I, marqueur de l’autophagie, a ete analyse par western-blot. Resultats et analyse statistique Au jour 17, les souris ABA presentaient un poids et une prise alimentaire plus faibles que les souris LFA et CT (p Conclusion Le metabolisme proteique est modifie de facon tissu-dependante chez la souris femelle au cours du modele ABA. L’hypothalamus est le seul tissu etudie ou la synthese proteique est augmentee, possiblement pour favoriser la prise alimentaire. Certains tissus peripheriques (colon, muscle soleaire) presentant au contraire une diminution de cette synthese proteique. Ces resultats suggerent des mecanismes adaptatifs contribuant a favoriser les fonctions cerebrales au cours de l’anorexie.

Anorexia nervosa (AN) is associated with low-grade systemic inflammation and altered gut microbiota. However, the molecular origin of the inflammation remains unknown. Toll-like receptors are key regulators of innate immune response and their activation seems also to be involved in the control of food intake. We used activity-based anorexia (ABA) model to investigate the role of TLR4 and its contribution in anorexia-associated low-grade inflammation. Here, we found that ABA affected early the intestinal inflammatory status and the hypothalamic response. Indeed, TLR4 was upregulated both on colonic epithelial cells and intestinal macrophages, leading to elevated downstream mucosal cytokine production. These mucosal changes occurred earlier than hypothalamic changes driving to increased levels of IL-1β and IL-1R1 as well as increased levels of plasma corticosterone. Paradoxically, TLR4-deficient mice exhibited greater vulnerability to ABA with increased mortality rate, suggesting a major contribution of TLR4-mediated responses during ABA-induced weight loss.

A role of gut-brain axis emerges in the pathophysiology of anorexia nervosa and maintaining adapted physical activity during refeeding remains discussed. We aimed to assess gastrointestinal protein metabolism and investigate the contribution of physical activity during refeeding in C57BL/6 mice with activity-based anorexia (ABA). ABA mice exhibited lower body weight and food intake with increase of lean mass/fat mass ratio and fat oxidation. Colonic permeability was increased in ABA. Ad libitum food access was then restored and ABA group was divided into two subgroups, with access to running wheel (ABA-PA) or not (ABA-NPA). After refeeding, fat free mass was completely restored only in ABA-PA. Colonic permeability was enhanced in ABA-NPA. Finally, muscle kynurenine conversion into kynurenic acid was lower in ABA-NPA who also exhibited altered behavior. Maintaining physical activity during refeeding may thus limit colonic hyperpermeability and improve behavior in anorectic mice.

International audience; The composition of gut microbiota has been associated with host metabolic phenotypes, but it is not known if gut bacteria may influence host appetite. Here we show that regular nutrient provision stabilizes exponential growth of E. coli, with the stationary phase occurring 20 min after nutrient supply accompanied by bacterial proteome changes, suggesting involvement of bacterial proteins in host satiety. Indeed, intestinal infusions of E. coli stationary phase proteins increased plasma PYY and their intraperitoneal injections suppressed acutely food intake and activated c-Fos in hypothalamic POMC neurons, while their repeated administrations reduced meal size. ClpB, a bacterial protein mimetic of alpha-MSH, was upregulated in the E. coli stationary phase, was detected in plasma proportional to ClpB DNA in feces, and stimulated firing rate of hypothalamic POMC neurons. Thus, these data show that bacterial proteins produced after nutrient-induced E. coli growth may signal meal termination. Furthermore, continuous exposure to E. coli proteins may influence long-term meal pattern.

Introduction et but de l’etude L’anorexie mentale est un trouble du comportement alimentaire dont la prise en charge est multimodale. Des donnees recentes suggerent que le maintien de l’activite physique au cours de la renutrition dans la prise en charge de l’anorexie mentale serait benefique et pourrait impliquer le metabolisme de la kynurenine, un metabolite du tryptophane. Nous avons etudie l’impact de l’activite physique sur le metabolisme central de la kynurenine dans un modele animal d’anorexie, le modele Activity-Based Anorexia (ABA). Materiel et methodes Des souris C57bl/6 ont ete reparties en deux groupes : temoin, avec alimentation ad libitum ; et ABA avec acces limite a l’alimentation et activite physique sur roue. Les souris ABA ont eu acces a l’alimentation progressivement limite de 6 h/j a j6 a 3 h/j a j9. Apres installation de la denutrition, les souris ABA ont retrouve un acces ad libitum a l’alimentation. Elles ont alors ete reparties en deux groupes : ABA-PA, avec activite physique et ABA-NPA, sans activite physique. Les souris ont ete placees dans des boites a doubles compartimentations (sombre et eclaire) pour etude du comportement, a la phase aigue de la denutrition et apres renutrition. Apres sacrifice, des RT-qPCR ont ete realisees au niveau de l’hypothalamus, l’hippocampe et l’amygdale pour etudier les marqueurs de neuroplasticite (GluA1, GluA2, CamKIIb, ARC) et de neuroinflammation (IBA1, CD11b), et les enzymes impliquees dans le metabolisme du tryptophane et de la kynurenine (KAT, TDO, TPH1). Un dosage de la corticosterone plasmatique par elisa a egalement ete realise. Resultats Le test comportemental retrouvait un comportement altere chez les souris ABA-NPA par rapport aux souris ABA-PA apres renutrition. La concentration plasmatique de corticosterone etait significativement plus elevee dans le groupe ABA-NPA (75,4 ± 4,5 contre 51,6 ± 6,5, p Conclusion Le maintien de l’activite physique au cours de la renutrition dans le modele ABA a des effets anxiolytiques et semble modifier le metabolisme hypothalamique du tryptophane et de la kynurenine.

Resume Au cours de differentes situations physiopathologiques, l’intestin est au cœur de la reponse metabolique et inflammatoire de l’organisme. Le maintien ou la restauration des fonctions intestinales et en particulier de la fonction de barriere intestinale est un element cle dans le devenir du patient. Le renouvellement cellulaire et proteique au niveau des muqueuses intestinales est important. Le renouvellement proteique au niveau de la muqueuse duodenale est ainsi estime a environ 50 %/jour chez l’homme. Or, il apparait que le metabolisme proteique intestinal peut etre modifie au cours de differentes situations physiopathologiques, ce qui pourrait contribuer a alterer la fonction de barriere intestinale. Le metabolisme proteique intestinal est egalement sensible a la qualite et a la quantite de nutriments ingeres. Cette revue presente les donnees disponibles sur la regulation du metabolisme proteique intestinal au cours de diverses situations physiopathologiques et l’impact des nutriments.

Introduction et but de l’etude L’anorexie mentale, trouble du comportement alimentaire restrictif, est souvent associe a des troubles fonctionnels intestinaux a type de constipation severe et de troubles de la vidange gastrique qui peuvent etre un frein a la renutrition. Les mecanismes impliques dans ces troubles sont cependant peu documentes. Le but de ce travail etait donc d’evaluer la vidange gastrique au cours du modele d’anorexie appele Activity-Based Anorexia (ABA) et d’explorer les mecanismes mis en jeu. Materiel et methodes Des souris femelles C57Bl/6 (n = 8/groupe) ont ete placees dans des cages avec une roue d’activite (ABA) ou non (groupe Controle et groupe acces limite a l’alimentation ou LFA). Les souris ABA et LFA ont eu un acces progressivement limite a l’alimentation de 6 h/jour a j6, a 3 h/jour a j9 et ce, jusqu’a la fin des experiences. A j17, apres une nuit de jeune et un acces a l’alimentation d’une heure, une mesure de la vidange gastrique (VG) a ete realisee en utilisant la formule suivante : VG ( %) = (1- poids sec du contenu gastrique/prise alimentaire) x 100. A partir des extraits gastriques (antre), une analyse proteomique comparative basee sur des gels 2D-PAGE a ete realisee, ainsi qu’une mesure de la synthese proteique par injection i.p. de puromycine 20 minutes avant l’euthanasie. Resultats et analyse statistique A j17, les souris ABA avaient une perte de poids plus prononcee que les souris LFA (−13,59 ± 2,05 % vs −8,06 ± 1,08 %) et une prise alimentaire cumulee plus faible (p Conclusion Le ralentissement de la vidange gastrique observe dans le modele ABA semble secondaire a la denutrition. L’implication de la diminution d’expression des proteines KRT19, DESM et KRT8 devra etre evaluee ainsi que le role du stress oxydant.

Introduction et but de l’etude L’obesite, enjeu majeur de sante publique, peut avoir des effets dichotomiques selon son grade. Ainsi, les sujets en obesite de grade I ou II semblent etre proteges du syndrome de l’intestin irritable (SII) alors que la prevalence du SII est augmentee d’un facteur 6 chez les sujets en obesite de grade III par rapport a la population generale. Le but de ce travail a donc ete d’evaluer la reponse de souris obeses a un modele de stress frequemment utilise pour etudier les mecanismes physiopathologiques du SII, le stress d’evitement de l’eau ou WAS. Materiel et methodes Des souris mâles C57Bl/6 ont ete soumises a un regime riche en lipides (60 % kcal sous forme lipidique ; HFD) ou non (SD) pendant 12 semaines (S12). A S12, les souris ont ete soumises ou non au stress d’evitement de l’eau (WAS) pendant 10 jours consecutifs, aboutissant ainsi a la formation de 4 groupes : SD-CT, SD-WAS, HFD-CT, HFD-WAS (n = 10/groupe). Des mesures de composition corporelle par EchoMRI ont ete realisees a S0, S12 et apres WAS. La permeabilite intestinale globale au cours du dernier jour de WAS a ete etudiee in vivo apres gavage des souris au FITC-dextran. Apres le sacrifice des souris, la permeabilite colique a ete evaluee sur des segments places en chambre de Ussing et la corticosterone plasmatique a ete mesuree par ELISA. Resultats et analyse statistique Les souris HFD presentaient un poids significativement plus eleve que les souris SD (a S12 : 39,8 ± 1,2 vs 29,7 ± 0,4 g, p Conclusion Les souris rendues obeses par une alimentation riche en lipides semblent plus sensibles au stress avec une elevation importante de la corticosterone et une augmentation de la permeabilite intestinale. Les mecanismes mis en jeu ainsi que l’impact sur les troubles fonctionnels intestinaux (motricite, sensibilite) restent a determiner.

Introduction et but de l’etude La denutrition, enjeu majeur de sante publique, est associee a de nombreuses complications dont les troubles depressifs ; la regulation de l’humeur est liee a la conversion du tryptophane en serotonine, mais il existe d’autres voies metaboliques du tryptophane. Ainsi, la kynurenine (KYN), metabolite du tryptophane sous l’action des enzymes TDO et IDO, peut etre metabolisee en acide kynurenique (KYNA) par les enzymes KATs ou en acide quinolinique (QA) par les enzymes KMO et kynureninase. Au niveau central, KYNA joue un role neuroprotecteur alors que le QA a des proprietes neurotoxiques. Une diminution du rapport KYNA/KYN au niveau peripherique est associee a des troubles psychiatriques : depression, anxiete. Le but de ce travail a donc ete d’evaluer le metabolisme de la kynurenine au cours de la denutrition chez la souris. Materiel et methodes Des souris mâles C57Bl/6 (n = 8–10/groupe) ont ete soumises soit au modele activity-based anorexia (ABA) soit a un regime pauvre en proteines (5 %, LPD). Lorsque la denutrition etait etablie (environ 20 % de perte de poids corporel), les souris ont ete soumises au test comportemental « clair-obscur » puis euthanasiees. Resultats et analyse statistique Une perte de poids de 19 % (p Conclusion Le metabolisme de la kynurenine est principalement modifie au niveau central dans le modele ABA (restriction), ce qui est associe a des troubles du comportement et une neuro-inflammation. Au contraire, dans le modele de denutrition proteique (LPD), seules des modifications peripheriques de ce metabolisme sont observees.

BACKGROUND Anorexia nervosa, a restrictive eating disorder, is often associated with gastrointestinal disorders, particularly a delayed gastric emptying. However, the mechanisms remained poorly documented. Thus, we aimed to evaluate gastric emptying and antrum protein metabolism in the Activity-Based Anorexia model (ABA). METHODS Females C57Bl/6 mice were randomized into 3 groups: Control, ABA, and Limited Food Access (LFA). Food access has been progressively limited from 6 h/day at day 6 to 3 h/day at day 9 and until day 17. ABA mice had free access to an activity wheel. Gastric emptying was assessed. On gastric extracts, a proteomic analysis was performed, as well as an evaluation of protein synthesis and protein oxidation. KEY RESULTS Both LFA and ABA mice exhibited a delayed gastric emptying compared with Controls (P

Introduction et but de l’etude L’anorexie mentale est un trouble du comportement alimentaire d’origine multifactorielle frequemment associee a des troubles fonctionnels intestinaux, comme une hypersensibilite viscerale et un trouble de la motricite intestinale. L’origine de ces troubles reste toutefois peu documentee et les mecanismes mal connus. Nous avons recemment montre des anomalies dans la structure intestinale ainsi qu’une augmentation de la permeabilite colique dans un modele animal d’anorexie associe a une activite physique (ABA). Pour mieux comprendre ces mecanismes, nous avons etudie le metabolisme proteique colique par une approche proteomique dans un modele animal d’anorexie (ABA). Materiel et methodes Des souris femelles C57Bl/6 ont ete reparties en trois groupes : controle (CT), ABA et acces limite a l’alimentation seul (LFA). Les souris ont ete placees dans des cages avec (ABA) ou sans (CT et LFA) roue d’activite. Les souris ABA et LFA ont eu un acces progressivement limite a l’alimentation de 6 h/j a j6, a 3 h/j a j9 et ce, jusqu’a la fin de l’experience. A j17, des souris ont ete euthanasiees. A partir des extraits coliques, une analyse proteomique comparative basee sur des gels 2D-PAGE a ete realisee. Apres analyse d’image, les proteines differentiellement exprimees (ratio d’expression > 1,4 ; n = 6/groupe, Anova, p Resultats et analyse statistique Les souris ABA presentaient une perte de poids plus importante que les souris LFA sans modification de la prise alimentaire. A J17, 7 proteines etaient differentiellement exprimees entre les 3 groupes (p Conclusion Nos resultats montrent donc des alterations specifiques du metabolisme proteique colique chez les souris ABA avec, en particulier, une activation de l’autophagie.

Glutamine, the most abundant amino acid in the human body, plays several important roles in the intestine. Previous studies showed that glutamine may affect protein expression by regulating ubiquitin-proteasome system. We thus aimed to evaluate the effects of glutamine on ubiquitinated proteins in human duodenal mucosa. Five healthy male volunteers were included and received during 5 h, on two occasions and in a random order, either an enteral infusion of maltodextrins alone (0.25 g kg(-1) h(-1), control), mimicking carbohydrate-fed state, or maltodextrins with glutamine (0.117 g kg(-1) h(-1), glutamine). Endoscopic duodenal biopsies were then taken. Total cellular protein extracts were separated by 2D gel electrophoresis and analyzed by an immunodetection using anti-ubiquitin antibody. Differentially ubiquitinated proteins were then identified by liquid chromatography-electrospray ionization MS/MS. Five proteins were differentially ubiquitinated between control and glutamine conditions. Among these proteins, we identified two chaperone proteins, Grp75 and hsp74. Grp75 was less ubiquitinated after glutamine infusion compared with control. In contrast, hsp74, also called Apg-2, was more ubiquitinated after glutamine. In conclusion, we provide evidence that glutamine may regulate ubiquitination processes of specific proteins, i.e., Grp75 and Apg-2. Grp75 has protective and anti-inflammatory properties, while Apg-2 indirectly regulates stress-induced cell survival and proliferation through interaction with ZO-1. Further studies should confirm these results in stress conditions.