RESUMEN

N6-methyladenosine (m6A) constitutes the paramount post-transcriptional modification within eukaryotic mRNA. This modification is subjected to stimulus-dependent regulation within the central nervous system of mammals, being influenced by sensory experiences, learning processes, and injuries. The patterns of m6A methylation within the hippocampal region of diabetes cognitive impairment (DCI) has not been investigated. A DCI model was established by feeding a high-fat diet to C57BL/6J mice. m6A and RNA sequencing was conducted to profile the m6A-tagged transcripts in the hippocampus. Methylated RNA immunoprecipitation with next-generation sequencing and RNA sequencing analyses yielded differentially m6A-modified and expressed genes in the hippocampus of DCI mice, which were enriched in pathways involving synaptic transmission and axonal guidance. Mechanistic analyses revealed a remarkable change in m6A modification levels through alteration of the mRNA expression of m6A methyltransferases (METTL3 and METTL14) and demethylase (FTO) in the hippocampus of DCI mice. We identified a co-mediated specific RNA regulatory strategy that broadens the epigenetic regulatory mechanism of RNA-induced neurodegenerative disorders associated with metabolic and endocrine diseases.

Asunto(s)

Disfunción Cognitiva , Diabetes Mellitus Experimental , Ratones , Animales , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/genética , Ratones Endogámicos C57BL , Metiltransferasas/metabolismo , ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Disfunción Cognitiva/genética , Mamíferos/metabolismo

RESUMEN

High-fat diet (HFD) and exercise remodel skeletal muscle mitochondria. The electron transfer flavoproteins (ETF) transfer reducing equivalents from ß-oxidation into the electron transfer system. Exercise may stimulate the synthesis of ETF proteins to increase lipid respiration. We determined mitochondrial remodeling for lipid respiration through ETF in the context of higher mitochondrial abundance/capacity seen in female mice. We hypothesized HFD would be a greater stimulus than exercise to remodel ETF and lipid pathways through increased protein synthesis alongside increased lipid respiration. Female C57BL/6J mice (n = 15 per group) consumed HFD or low-fat diet (LFD) for 4 weeks then remained sedentary (SED) or completed 8 weeks of treadmill training (EX). We determined mitochondrial lipid respiration, RNA abundance, individual protein synthesis, and abundance for ETFα, ETFß, and ETF dehydrogenase (ETFDH). HFD increased absolute and relative lipid respiration (p = 0.018 and p = 0.034) and RNA abundance for ETFα (p = 0.026), ETFß (p = 0.003), and ETFDH (p = 0.0003). HFD increased synthesis for ETFα and ETFDH (p = 0.0007 and p = 0.002). EX increased synthesis of ETFß and ETFDH (p = 0.008 and p = 0.006). Higher synthesis rates of ETF were not always reflected in greater protein abundance. Greater synthesis of ETF during HFD indicates mitochondrial remodeling which may contribute higher mitochondrial lipid respiration through enhanced ETF function.

Asunto(s)

Dieta Alta en Grasa , Flavoproteínas Transportadoras de Electrones , Femenino , Animales , Ratones , Flavoproteínas Transportadoras de Electrones/genética , Flavoproteínas Transportadoras de Electrones/metabolismo , Dieta Alta en Grasa/efectos adversos , Ratones Endogámicos C57BL , Músculo Esquelético/metabolismo , Lípidos , Respiración , ARN/metabolismo

RESUMEN

Obesity is one of the chronic diseases that increase annually and cause cardiovascular disease, which is the main cause of death worldwide. So, this study aims to evaluate the role of the two potential probiotics: Lactiplantibacillus plantarum Pro1 and Lacticaseibacillus rhamnosus Pro2, isolated from the fermented milk and corn silage as anti-obesity supplements. Seventy-five male BALB/c mice were distributed to five groups (control, obesity, obesity plus L. plantarum (OLP), obesity plus L. rhamnosus (OLR) and obesity plus mixture of two strains (OM)). The body weight, lipid profile, histopathology and enzymes of liver were assessed. RT-PCR was used to determine the expression of CYP7A1, ALTG4, TNFα and ROR genes.The findings show that the obesity group recorded the significant highest value of the body weight, TC, TG, LDL, AST and ALT, while OLP group recorded the significant lowest value. Liver tissue of obesity group has necrosis and fatty changes, while the OLP group was related to the control group. The findings of RT-PCR show non-significant differences between the control group and the OLP group, with significant differences between the control group and the set groups in expression of CYP7A1, ALTG4, TNFα and ROR genes. L. plantarum Pro1 reduced the expression of inflammation genes (TNFα and ROR), and increase the expression of the lipid metabolism genes (CYP7A1, ALTG4) to reduce the inflammatory effects of obesity in the liver, and decrease the cholesterol level in serum. Therefore, L. plantarum Pro1 is useful as anti-obesity supplements and an eliminator of the relevant diseases.

Asunto(s)

Lactobacillus plantarum , Probióticos , Masculino , Ratones , Animales , Factor de Necrosis Tumoral alfa/genética , Lactobacillus plantarum/genética , Lactobacillus plantarum/metabolismo , Obesidad/metabolismo , Peso Corporal , Probióticos/farmacología

RESUMEN

This study investigated the effects of xylooligosaccharide (XOS) supplementation on growth, intestinal enzyme, antioxidant and immune-related genes in common carp Cyprinus carpio fed a high-fat diet (HFD). One hundred and ninety two fish with an initial weight of 19.61 ± 0.96 g were allocated into 24 tanks (eight fish per tank in four replicate) and were fed the control diet, HFD, HFD with 0.5%, 1%, 2% and 3% XOS supplementation. From the result, fish offered HFD with 1% XOS supplementation significantly obtained a higher body mass index and feed efficiency ratio, whereas condition factor was higher in fish fed HFD supplemented with 2% XOS but no difference was attributed to other supplemented group compared to control group. Also, fish fed HFD supplemented with 1%-2% XOS significantly improved protease, lipase, creatine kinase and sodium/potassium ATPase activities compared to other groups. Fish offered HFD were significantly lower in superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), myeloperoxidase, acid phosphatase, lysozyme activities and immunoglobulin content, but the opposite result was found for aspartate transaminase, alanine transaminase activities, malondialdehyde, protein carbonyl and cortisol content as compared with the control. However, this effect was reversed with HFD supplemented with XOS. Also, interleukin 1ß, interleukin 8, tumour necrosis factors, interferons, caspase-3 and caspase-9 in the intestine were all up-regulated in the HFD group, while the reverse pattern was found in SOD, GPX, lysozyme-C, complement 3 and mucin 5b (muc5b), than the control group. These effects were all enhanced by feeding the XOS diet, especially those fed 1%-3% supplementation. In conclusion, XOS inclusion can improve the growth, digestive enzymes, antioxidants and immune response of common carp fed HFD.

Asunto(s)

Carpas , Alimentación Animal/análisis , Animales , Antioxidantes/metabolismo , Carpas/metabolismo , Dieta/veterinaria , Dieta Alta en Grasa , Suplementos Dietéticos , Glucuronatos , Intestinos , Oligosacáridos , Prebióticos

RESUMEN

Calcific aortic valve disease (CAVD) is caused by the initiation of the thickening and calcification of valve leaflets by valve interstitial cells (VICs). Cell metabolic changes during the CAVD process are a new field of basic research on this disease. The present study aimed to investigate whether andrographolide (AGP) could attenuate the calcification of aortic valves by regulating cell metabolism. Gas chromatography-mass spectroscopy (GC-MS) metabolome analysis was utilized to investigate the changes in the metabolites of VICs from healthy and CAVD samples. Cell growth and the osteogenic differentiation of human VICs (hVICs) were assessed using a CCK8 assay and Alizarin Red S staining, respectively. The expression of two calcification-related markers, RUNX2 and ALP, was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence staining. Molecular docking was used to detect the interaction between AGP and monoglyceride lipase (MGLL). The high-fat-fed ApoE-/- mice aortic valve calcification animal model was used to verify the effect of AGP on CAVD in vivo. Metabolome analysis showed that the metabolites of VICs from healthy and CAVD samples were highly enriched in the biosynthesis of unsaturated fatty acids and glycerolipid metabolism. The top six highlighted metabolites were selected to reveal a high regulation of lipids in VICs from CAVD. AGP significantly suppressed the calcific differentiation of VICs while it decreased the accumulation of the above six metabolites, 1-monopalmitic, palmitic acid, glycerol, l-asparagine, tetraethylene glycol, and stearic acid induced by osteogenic medium (OM) stimulation. These metabolites were highly correlated with the calcific marker ALP and showed a positive correlation with CAVD. In the comprehensive assessment, MGLL, associated with glycerol synthesis, was selected as the molecular target of AGP in inhibiting the calcific phenotype of transforming hVICs. The in vivo results revealed that AGP visibly ameliorated aortic valve calcification by reducing Von Kossa and ALP staining, which was positively correlated with MGLL expression. AGP ameliorated aortic valve calcification by regulating lipid biosynthesis and glycerolipid metabolism targeting MGLL expression in vitro and in vivo. It is a potent therapeutic supplement that prevents the occurrence of heart valve calcification disease by regulating cell metabolism.

Asunto(s)

Válvula Aórtica , Monoacilglicerol Lipasas , Animales , Células Cultivadas , Diterpenos , Ratones , Simulación del Acoplamiento Molecular , Osteogénesis

RESUMEN

Substantial evidence indicated that maternal malnutrition could increase the susceptibility to obesity, insulin resistance, and type 2 diabetes in adulthood. It is increasingly apparent that the brain, especially the hypothalamus, plays a critical role in glucose homeostasis. However, little information is known about the mechanisms linking maternal protein restriction combined with post-weaning high-fat (HF) feeding with altered expression of brain neurotransmitters, and investigations into the epigenetic modifications of hypothalamus in offspring have not been fully elucidated. Our objective was to explore the effects of maternal protein restriction combined with post-weaning HF feeding on glucose metabolism and hypothalamic POMC methylation in male offspring mice. C57/BL6 mice were fed on either low-protein (LP) or normal chow (NC) diet throughout gestation and lactation. Then, the male offspring were randomly weaned to either NC or high-fat (HF) diet until 32 weeks of age. Gene expressions and DNA methylation of hypothalamic proopiomelanocortin (POMC) and melanocortin receptor 4 (MC4R) were determined in male offspring. The results showed that birth weights and body weights at weaning were both significantly lower in male offspring mice of the dams fed with a LP diet. Maternal protein restriction combined with post-weaning high-fat feeding, predisposes higher body weight, persistent glucose intolerance (from weaning to 32 weeks of age), hyperinsulinemia, and hyperleptinemia in male offspring mice. POMC and MC4R expressions were significantly increased in offspring mice fed with maternal LP and postnatal high-fat diet (P < 0.05). Furthermore, maternal protein restriction combined with post-weaning high-fat feeding induced hypomethylation of POMC promoter in the hypothalamus (P < 0.05) and POMC-specific methylation (%) was negatively correlated with the glucose response to a glucose load in male offspring mice (r = -0.42, P = 0.039). In conclusion, maternal LP diet combined with post-weaning high-fat feeding predisposed the male offspring to impaired glucose metabolism and hypothalamic POMC hypomethylation. These findings can advance our thinking about hypothalamic POMC gene methylation between maternal LP diet combined with post-weaning high-fat feeding and metabolic health in offspring.

RESUMEN

Lipid overload of the mitochondria is linked to the development of insulin resistance in skeletal muscle which may be a contributing factor to the progression of type 2 diabetes during obesity. The targeted degradation of mitochondria through autophagy, termed mitophagy, contributes to the mitochondrial adaptive response to changes in dietary fat. Our previous work demonstrates long-term (2-4 months) consumption of a high-fat diet increases mitochondrial lipid oxidation capacity but does not alter markers of mitophagy in mice. The purpose of this study was to investigate initial stages of mitochondrial respiratory adaptations to high-fat diet and the activation of mitophagy. C57BL/6J mice consumed either a low-fat diet (LFD, 10% fat) or high-fat diet (HFD, 60% fat) for 3 or 7 days. We measured skeletal muscle mitochondrial respiration and protein markers of mitophagy in a mitochondrial-enriched fraction of skeletal muscle. After 3 days of HFD, mice had lower lipid-supported oxidative phosphorylation alongside greater electron leak compared with the LFD group. After 7 days, there were no differences in mitochondrial respiration between diet groups. HFD mice had greater autophagosome formation potential (Beclin-1) and greater activation of mitochondrial autophagy receptors (Bnip3, p62) in isolated mitochondria, but no difference in downstream autophagosome (LC3II) or lysosome (Lamp1) abundance after both 3 and 7 days compared with the LFD groups. In cultured myotubes, palmitate treatment decreased mitochondrial membrane potential and hydrogen peroxide treatment increased accumulation of upstream mitophagy markers. We conclude that several days of high-fat feeding stimulated upstream activation of skeletal muscle mitophagy, potentially through lipid-induced oxidative stress, without downstream changes in respiration.

Asunto(s)

Lípidos/química , Mitocondrias/patología , Mitofagia/fisiología , Músculo Esquelético/fisiología , Animales , Autofagia , Beclina-1/biosíntesis , Diabetes Mellitus Tipo 2/genética , Dieta con Restricción de Grasas , Dieta Alta en Grasa , Ácidos Grasos/química , Ácidos Grasos/metabolismo , Peróxido de Hidrógeno/química , Peroxidación de Lípido , Lisosomas/metabolismo , Masculino , Potencial de la Membrana Mitocondrial , Proteínas de la Membrana/biosíntesis , Ratones , Ratones Endogámicos C57BL , Proteínas Asociadas a Microtúbulos/biosíntesis , Mitocondrias/metabolismo , Proteínas Mitocondriales/biosíntesis , Obesidad/genética , Estrés Oxidativo , Oxígeno/química , Fenotipo , Especies Reactivas de Oxígeno , Factores de Tiempo

RESUMEN

The reward system plays an important role in the pathogenesis of not only drug addiction, but also diet-induced obesity. Recent studies have shown that insulin and leptin receptor signaling in the ventral tegmental area (VTA) regulate energy homeostasis and that their dysregulation is responsible for obesity and altered food preferences. Although a high-fat diet (HFD) induces inflammation that leads to insulin and leptin resistance in the brain, it remains unclear whether HFD induces inflammation in the VTA. In the present study, we placed male mice on a chow diet or HFD for 3, 7, and 28 days and evaluated the mRNA expression of inflammatory cytokines and microglial activation markers in the VTA. The HFD group showed significantly elevated mRNA expressions of IL1ß at 3 days; tumor necrosis factor-alpha (TNFα), IL1ß, IL6, Iba1, and CD11b at 7 days; and TNFα, IL1ß, Iba1, and CD11b at 28 days. The changes in TNFα were also confirmed in immunohistochemical analysis. Next, after administration of chow or HFD for 7 days, we selected mice with equal weights in both groups. In experiments using these mice, Akt phosphorylation in the VTA was significantly decreased after intracerebroventricular injection of insulin, whereas no change in STAT3 phosphorylation was found with leptin. Taken together, these results suggest that HFD induces inflammation at least partly associated with microglial activation in the VTA leading to insulin resistance, independently of the energy balance. Our data provide new insight into the pathophysiology of obesity caused by a dysfunctional reward system under HFD conditions.

Asunto(s)

Resistencia a la Insulina , Animales , Dieta Alta en Grasa/efectos adversos , Inflamación , Masculino , Ratones , Ratones Endogámicos C57BL , Obesidad , Área Tegmental Ventral

RESUMEN

Obesity is closely linked with type 2 diabetes and the effective therapies on obesity-associated diabetes are under development. The aim of this study was undertaken to investigate whether the inhibition of the augmented CCR5-mediated signaling could be a common target for treatment of obesity-associated insulin resistance and impairment of pancreatic insulin secretion in high-fat diet (HFD) fed rats and CCR5 knockout mice and also in isolated islets and RIN-m5F cells. Conducted with SD rats, HFD-induced body weight gain was significantly decreased in those combined with Maraviroc treatment, but food intake remained similar compared to control. Maraviroc also significantly improved the impaired oral glucose tolerance test (OGTT). As compared with wild-type mice, CCR5 deletion significantly attenuated the HFD-induced increases in glucose area under curve of OGTT and the value of HOMA-IR as well as plasma lipid profile. It also reversed the HFD-suppressed gene expressions of GLUT4 and IRS-1 in adipose tissue. On the other hand, the HFD-associated islet macrophage and T-cell infiltration were significantly decreased in CCR5 KO mice. H2O2 significantly suppressed glucose-stimulated insulin secretion (GSIS) is isolated islets, which were significantly reversed in those cotreated with CCR5 mAb. H2O2 failed to change GSIS in those of CCR5 KO mice. The palmitate-induced reactive oxygen species production was significantly decreased in those cotreated with CCR5 antagonist in RIN-m5F cells. Collectively, it is suggested that targeting inhibition of the CCR5 mediated inflammatory pathway could not only improve obesity-associated insulin resistance but also directly alleviate pancreatic ß-cell dysfunction.

Asunto(s)

Glucemia/efectos de los fármacos , Antagonistas de los Receptores CCR5/farmacología , Resistencia a la Insulina , Células Secretoras de Insulina/efectos de los fármacos , Insulina/metabolismo , Maraviroc/farmacología , Obesidad/prevención & control , Receptores CCR5/efectos de los fármacos , Animales , Glucemia/metabolismo , Línea Celular Tumoral , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patología , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/complicaciones , Obesidad/metabolismo , Obesidad/fisiopatología , Estrés Oxidativo/efectos de los fármacos , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Receptores CCR5/genética , Receptores CCR5/metabolismo , Vías Secretoras , Transducción de Señal , Técnicas de Cultivo de Tejidos

RESUMEN

NEW FINDINGS: What is the central question of this study? Does achieving energy balance mainly with ingested fat in a 'sleep-low' model of training with low muscle glycogen affect the early training adaptive response during recovery? What is the main finding and its importance? Replenishing the energy expended during exercise mainly from ingested fat to achieve energy balance in a 'sleep-low' model does not enhance the response of skeletal muscle markers of early adaptation to training and impairs glycaemic control the morning after compared to training with low energy availability. These findings are important for optimizing post-training dietary recommendations in relation to energy balance and macronutrient intake. ABSTRACT: Training with low carbohydrate availability (LCHO) has been shown to acutely enhance endurance training skeletal muscle response, but the concomitant energy deficit (ED) in LCHO interventions has represented a confounding factor in past research. This study aimed at determining if achieving energy balance with high fat (EB-HF) acutely enhances the adaptive response in LCHO compared to ED with low fat (ED-LF). In a crossover design, nine well-trained males completed a 'sleep-low' protocol: on day 1 they cycled to deplete muscle glycogen while reaching a set energy expenditure (30 kcal (kg of fat free mass (FFM))-1 ). Post-exercise, low carbohydrate, protein-matched meals completely (EB-HF, 30 kcal (kg FFM)-1 ) or partially (ED-LF, 9 kcal (kg FFM)-1 ) replaced the energy expended, with the majority of energy derived from fat in EB-HF. In the morning of day 2, participants exercised fasted, and skeletal muscle and blood samples were collected and a carbohydrate-protein drink was ingested at 0.5 h recovery. Muscle glycogen showed no treatment effect (P < 0.001) and decreased from 350 ± 98 to 192 ± 94 mmol (kg dry mass)-1 between rest and 0.5 h recovery. Phosphorylation status of the mechanistic target of rapamycin and AMP-activated protein kinase pathway proteins showed only time effects. mRNA expression of p53 increased after exercise (P = 0.005) and was higher in ED-LF at 3.5 h compared to EB-HF (P = 0.027). Plasma glucose and insulin area under the curve (P < 0.04) and peak values (P ≤ 0.05) were higher in EB-HF after the recovery drink. Achieving energy balance with a high-fat meal in a 'train-low' ('sleep-low') model did not enhance markers of skeletal muscle adaptation and impaired glycaemia in response to a recovery drink following training in the morning.

Asunto(s)

Adaptación Fisiológica/fisiología , Grasas de la Dieta/efectos adversos , Metabolismo Energético/fisiología , Ejercicio Físico/fisiología , Comidas/fisiología , Músculo Esquelético/fisiología , Sueño/fisiología , Adulto , Glucemia/fisiología , Estudios Cruzados , Dieta , Carbohidratos de la Dieta , Ingestión de Alimentos/fisiología , Glucógeno/metabolismo , Humanos , Masculino , Resistencia Física/fisiología , Descanso/fisiología

RESUMEN

Obesity is a current threat to health care systems, affecting approximately 13% of the world's adult population, and over 18% children and adolescents. The rise of obesity is fuelled by inadequate life style habits, as consumption of diets rich in fats and sugars which promote, additionally, the development of associated comorbidities. Obesity results from a neuroendocrine imbalance in the cerebral mechanisms controlling food intake and energy expenditure, including the hypothalamus and the reward and motivational centres. Specifically, high-fat diets are known to trigger an early inflammatory response in the hypothalamus that precedes weight gain, is time-dependent, and eventually extends to the remaining appetite regulating regions in the brain. Multiple magnetic resonance imaging (MRI) and spectroscopy (MRS) methods are currently available to characterize different features of cerebral obesity, including diffusion weighted, T2 and volumetric imaging and 1H and 13C spectroscopic evaluations. In particular, consistent evidences have revealed increased water diffusivity and T2 values, decreased grey matter volumes, and altered metabolic profiles and fluxes, in the brain of animal models and in obese humans. This review provides an integrative interpretation of the physio-pathological processes associated with obesity development in the brain, and the MRI and MRS methods implemented to characterize them.

Asunto(s)

Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/fisiopatología , Susceptibilidad a Enfermedades , Imagen por Resonancia Magnética , Obesidad/etiología , Animales , Biomarcadores , Corteza Cerebral/patología , Dieta , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Neuroimagen Funcional/métodos , Humanos , Hipotálamo/diagnóstico por imagen , Hipotálamo/patología , Hipotálamo/fisiopatología , Estilo de Vida , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética , Modelos Biológicos , Tamaño de los Órganos

RESUMEN

Loss of beta cell identity and subsequent transdifferentiation of beta-to-alpha cells is implicated in the pathogenesis of diabetes. In addition, sodium-glucose transport protein 2 (SGLT2) inhibition has been linked to altered alpha-cell function. To investigate these phenomenon, lineage tracing of beta-cells was examined following 10-12 days dapagliflozin (1 or 5 mg/kg, once daily, as appropriate) treatment in multiple low-dose streptozotocin (STZ), high fat fed (HFF) or hydrocortisone (HC) transgenic Ins1Cre/+/Rosa26-eYFP mouse models of diabetes and insulin resistance. As anticipated, STZ, HFF and HC treated mice developed characteristic features of insulin deficiency or resistance. Dapagliflozin elicited differing beneficial effects depending on the aetiology of syndrome studied. The SGLT2 inhibitor efficiently promoted (P < 0.001) weight loss in HFF and STZ mice, whilst in HC mice it reduced (P < 0.001) energy intake, without an impact on body weight. Despite lacking significant effects on glycaemia, 1 mg/kg dapagliflozin consistently decreased both plasma and pancreatic glucagon. This was associated with increased pancreatic insulin in STZ and HFF mice. In STZ and HFF mice, beta cell proliferation and Pdx1 expression were enhanced by dapagliflozin, with a further increase in overall glucagon staining in HFF islets. Islet, beta- and alpha-cell areas were increased in dapagliflozin treated HC mice, which appeared to be linked to decreased alpha- and beta-cell apoptosis. Although the diabetes-like syndromes induced clear alterations in islet cell transdifferentiation, treatment with dapagliflozin (1 mg/kg) had no significant impact on this process, with 5 mg/kg marginally decreasing loss of beta-cells identity in STZ mice. These data suggest that SGLT2 inhibitors have positive effects on beta cells and decrease plasma and pancreatic glucagon, independent of changes in ambient glucose levels. Our combined data indicate that SGLT2 inhibitors do not directly induce hyperglucagonaemia.

Asunto(s)

Compuestos de Bencidrilo/farmacología , Diabetes Mellitus Experimental/tratamiento farmacológico , Glucagón/metabolismo , Glucósidos/farmacología , Células Secretoras de Insulina/efectos de los fármacos , Inhibidores del Cotransportador de Sodio-Glucosa 2/farmacología , Animales , Glucemia/metabolismo , Peso Corporal/efectos de los fármacos , Transdiferenciación Celular/efectos de los fármacos , Diabetes Mellitus Experimental/etiología , Diabetes Mellitus Experimental/patología , Dieta Alta en Grasa/efectos adversos , Ingestión de Energía/efectos de los fármacos , Células Secretoras de Glucagón/efectos de los fármacos , Células Secretoras de Glucagón/patología , Proteínas de Homeodominio/metabolismo , Hidrocortisona/toxicidad , Insulina/metabolismo , Resistencia a la Insulina , Células Secretoras de Insulina/patología , Islotes Pancreáticos/efectos de los fármacos , Islotes Pancreáticos/patología , Masculino , Ratones Transgénicos , Estreptozocina , Transactivadores/metabolismo

RESUMEN

Transdifferentiation of beta- to alpha-cells has been implicated in the pathogenesis of diabetes. To investigate the impact of contrasting aetiologies of beta-cell stress, as well as clinically approved incretin therapies on this process, lineage tracing of beta-cells in transgenic Ins1 Cre/+/Rosa26-eYFP mice was investigated. Diabetes-like syndromes were induced by streptozotocin (STZ), high fat feeding (HFF) or hydrocortisone (HC), and effects of treatment with liraglutide or sitagliptin were investigated. Mice developed the characteristic metabolic features associated with beta-cell destruction or development of insulin resistance. Liraglutide was effective in preventing weight gain in HFF mice, with both treatments decreasing energy intake in STZ and HC mice. Treatment intervention also significantly reduced blood glucose levels in STZ and HC mice, as well as increasing either plasma or pancreatic insulin while decreasing circulating or pancreatic glucagon in all models. The recognised changes in pancreatic morphology induced by STZ, HFF or HC were partially, or fully, reversed by liraglutide and sitagliptin, and related to advantageous effects on alpha- and beta-cell growth and survival. More interestingly, induction of diabetes-like phenotype, regardless of pathogenesis, led to increased numbers of beta-cells losing their identity, as well as decreased expression of Pdx1 within beta-cells. Both treatment interventions, and especially liraglutide, countered detrimental islet cell transitioning effects in STZ and HFF mice. Only liraglutide imparted benefits on beta- to alpha-cell transdifferentiation in HC mice. These data demonstrate that beta- to alpha-cell transdifferentiation is a common consequence of beta-cell destruction or insulin resistance and that clinically approved incretin-based drugs effectively limit this.

Asunto(s)

Transdiferenciación Celular/efectos de los fármacos , Células Secretoras de Glucagón/efectos de los fármacos , Células Secretoras de Insulina/efectos de los fármacos , Liraglutida/farmacología , Fosfato de Sitagliptina/farmacología , Animales , Antiinflamatorios/farmacología , Apoptosis/efectos de los fármacos , Glucemia/metabolismo , Proliferación Celular/efectos de los fármacos , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Glucagón/sangre , Glucagón/metabolismo , Células Secretoras de Glucagón/metabolismo , Hidrocortisona/farmacología , Hipoglucemiantes/farmacología , Insulina/sangre , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Ratones Endogámicos C57BL , Ratones Transgénicos

RESUMEN

Cholesterol and bile acid (BA) homeostasis plays a central role in systemic metabolism. Accumulating evidence suggests a key regulatory function of the circadian clock, our biological timer, in lipid metabolism, particularly cholesterol and bile acid flux. Previously, we showed that Nobiletin (NOB), a natural compound targeting the ROR (Retinoic acid receptor-related orphan receptor) nuclear receptors in the circadian oscillator, strongly protects lipid homeostasis, including normal serum cholesterol levels in high-fat (HF) fed mice at both young and old ages. In this study, we further examined the role of NOB in cholesterol metabolism in HF-fed aged mice, and found that NOB lowered the serum LDL/VLDL cholesterol levels and consequently the LDL/HDL ratio. BA levels in the serum were markedly reduced in the HF.NOB group, and examination of additional hepatic markers further indicate a protective role of NOB in the liver. At the molecular level, whereas HF feeding downregulated hepatic expression of several ROR target genes involved in bile acid synthesis, NOB treatment (HF.NOB) was able to rescue it. In accordance, fecal BA excretion was enhanced by NOB, and microbial 16S sequencing revealed alteration of several taxa known to be involved in secondary BA production in the gut. Together, these results demonstrate concerted effects of the clock-modulating compound NOB in cholesterol and BA metabolism, suggesting pharmacological manipulation of the clock as a novel therapeutic strategy against metabolic disorders and age-related decline.

Asunto(s)

Envejecimiento , Ácidos y Sales Biliares/metabolismo , Colesterol/metabolismo , Relojes Circadianos , Flavonas/farmacología , Hígado/metabolismo , Animales , Colesterol/sangre , Dieta Alta en Grasa , Microbioma Gastrointestinal , Ratones

RESUMEN

Growth restriction programs adult bone deficits and increases the risk of obesity, which may be exacerbated during pregnancy. We aimed to determine if high-fat feeding could exacerbate the bone deficits in pregnant growth restricted dams, and whether treadmill exercise would attenuate these deficits. Uteroplacental insufficiency was induced on embryonic day 18 (E18) in Wistar Kyoto (WKY) rats using bilateral uterine vessel ligation (restricted) or sham (control) surgery. The F1 females consumed a standard or high-fat (HFD) diet from 5 weeks, commenced treadmill exercise at 16 weeks, and they were mated at 20 weeks. Femora and plasma from the pregnant dams were collected at post-mortem (E20) for peripheral quantitative computed tomography (pQCT), mechanical testing, histomorphometry, and plasma analysis. Sedentary restricted females had bone deficits compared to the controls, irrespective of diet, where such deficits were prevented with exercise. Osteocalcin increased in the sedentary restricted females compared to the control females. In the sedentary HFD females, osteocalcin was reduced and CTX-1 was increased, with increased peak force and bending stress compared to the chow females. Exercise that was initiated before and continued during pregnancy prevented bone deficits in the dams born growth restricted, whereas a HFD consumption had minimal bone effects. These findings further highlight the beneficial effects of exercise for individuals at risk of bone deficits.

Asunto(s)

Densidad Ósea/fisiología , Dieta Alta en Grasa , Retardo del Crecimiento Fetal , Condicionamiento Físico Animal , Preñez , Animales , Peso Corporal , Femenino , Insuficiencia Placentaria , Embarazo , Distribución Aleatoria , Ratas

RESUMEN

A healthy diet improves life expectancy and helps to prevent common chronic diseases such as type 2 diabetes (T2D) and obesity. The mechanisms driving these effects are not fully understood, but are likely to involve epigenetics. Epigenetic mechanisms control gene expression, maintaining the DNA sequence, and therefore the full genomic information inherited from our parents, unchanged. An interesting feature of epigenetic changes lies in their dynamic nature and reversibility. Accordingly, they are susceptible to correction through targeted interventions. Here we will review the evidence supporting a role for nutritional factors in mediating metabolic disease risk through DNA methylation changes. Special emphasis will be placed on the potential of using DNA methylation traits as biomarkers to predict risk of obesity and T2D as well as on their response to dietary and pharmacological (epi-drug) interventions.

Asunto(s)

Metilación de ADN , Diabetes Mellitus Tipo 2/etiología , Dieta , Susceptibilidad a Enfermedades , Obesidad/etiología , Animales , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Modelos Animales de Enfermedad , Epigénesis Genética , Humanos , Ratones , Obesidad/tratamiento farmacológico , Obesidad/metabolismo , Medición de Riesgo , Factores de Riesgo

RESUMEN

Exercise can improve obesity and metabolic disorders in mice fed a high-fat diet (HFD), but the role of AMPKα2 in the process remains unclear. The aim of this study was to investigate the role of AMPKα2 in the exercise-induced improvements in glucose tolerance and metabolic turnover in obesity mice. Male wild-type mice (n=12) and AMPKα2 knockout (AMPKα2 KO) mice (n=12) were fed a HFD for 16 wk and were then randomly divided into four groups: WT HFD group (WT HF), AMPKα2 KO HFD group (AMPKα2 KO HF), WT HFD exercise group (WT HE), and AMPK HFD exercise group (AMPKα2 KO HE). The HF groups continue to be fed a HFD from 16 wk to 24 wk, and the HE groups were fed a HFD and performed exercise training. After 8 wk of exercise, all mice were placed in an energy metabolism chamber to test their metabolic turnover, include locomotor activity, food intake, oxygen consumption (VO2), carbon dioxide production (VCO2), energy expenditure (EE) and respiratory exchange ratio (RER), over a period of 3 d. Exercise improved glucose tolerance, VO2, VCO2 and EE in mice fed a HFD (p<0.05). The VO2, VCO2 and EE in AMPKα2 KO HE group were lower than these in WT HE group (p<0.05). Our findings revealed exercise improved glucose tolerance and metabolic disorders in C57 and AMPKα2 KO mice fed a HFD. AMPKα2 is not essential for exercise-induced improvements in glucose tolerance and metabolic disorders.

Asunto(s)

Proteínas Quinasas Activadas por AMP/deficiencia , Glucemia/metabolismo , Dieta Alta en Grasa , Enfermedades Metabólicas/metabolismo , Condicionamiento Físico Animal/fisiología , Animales , Peso Corporal/fisiología , Dióxido de Carbono/metabolismo , Metabolismo Energético/fisiología , Masculino , Ratones , Ratones Obesos , Consumo de Oxígeno/fisiología

RESUMEN

BACKGROUND: High-fat feeding and hyperglycemia, key risk factors for the development of metabolic syndrome (MetS), are emerging to associate with increased risk of developing dementia and cognitive decline. Despite this, clinical and experimental studies have yet to elucidate the specific contributions of either high-fat feeding or hyperglycemia to potential neuroinflammatory components. In this study, we delineate these individual components of MetS in the development of neuroinflammation. METHODS: Male C57Bl/6 J adult mice were treated with either citrate vehicle (CIT) or streptozotocin (STZ; 55 mg/kg) 3, 5 and 7 days before commencement of either a normal or high-fat diet for 9 or 18 weeks. By creating separate models of high-fat feeding, STZ-induced hyperglycemia, as well as in combination, we were able to delineate the specific effects of a high-fat diet and hyperglycemia on the brain. Throughout the feeding regime, we measured the animals' body weight and fasting blood glucose levels. At the experimental endpoint, we assessed plasma levels of insulin, glycated haemoglobin and performed glucose tolerance testing. In addition, we examined the effect of high fat-feeding and hyperglycemia on the levels of systemic inflammatory cytokines, gliosis in the hippocampus and immune infiltration in cerebral hemispheric tissue. Furthermore, we used intravital multiphoton microscopy to assess leukocyte-endothelial cell interactions in the cerebral vasculature of mice in vivo. RESULTS: We showed that acute hyperglycemia induces regional-specific effects on the brain by elevating microglial numbers and promotes astrocytosis in the hippocampus. In addition, we demonstrated that chronic hyperglycemia supported the recruitment of peripheral GR1+ granulocytes to the cerebral microvasculature in vivo. Moreover, we provided evidence that these changes were independent of the systemic inflammation associated with high-fat feeding. CONCLUSIONS: Hyperglycemia alone preferentially induces microglial numbers and astrocytosis in the hippocampus and is associated with the peripheral recruitment of leukocytes to the cerebrovasculature, but not systemic inflammation. High-fat feeding alone, and in combination with hyperglycemia, increases the systemic pro-inflammatory cytokine milieu but does not result in brain-specific immune gliosis. These results shed light on the specific contributions of high-fat feeding and hyperglycemia as key factors of MetS in the development of neuroinflammation.

Asunto(s)

Dieta Alta en Grasa/efectos adversos , Encefalitis/etiología , Hiperglucemia/complicaciones , Sistema Inmunológico/patología , Síndrome Metabólico/complicaciones , Síndrome Metabólico/etiología , Animales , Antibióticos Antineoplásicos/toxicidad , Glucemia , Proteínas de Unión al Calcio/metabolismo , Citocinas/metabolismo , Modelos Animales de Enfermedad , Encefalitis/inmunología , Encefalitis/patología , Ayuno/sangre , Hiperglucemia/inducido químicamente , Hiperglucemia/patología , Insulina/sangre , Leucocitos/efectos de los fármacos , Leucocitos/metabolismo , Leucocitos/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Proteínas de Microfilamentos/metabolismo , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/patología , Proteínas del Tejido Nervioso/metabolismo , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Estreptozocina/toxicidad

RESUMEN

Multiple aspects of mitochondrial function and dynamics remain poorly studied in the skeletal muscle of pediatric models in response to a short-term high-fat diet (HFD). This study investigated the impact of a short-term HFD on mitochondrial function and dynamics in the oxidative soleus (SOL) and glycolytic extensor digitorum longus (EDL) muscles in young rats. Young male Wistar rats were submitted to either HFD or normal chow (NCD) diets for 14 days. Permeabilized myofibers from SOL and EDL were prepared to assess mitochondrial respiration and reactive oxygen species (ROS) production. The expression and content of protein involved in mitochondrial metabolism and dynamics (fusion/fission) were also quantified. While no effects of HFD was observed on mitochondrial respiration when classical complex I and II substrates were used, both SOL and EDL of rats submitted to a HFD displayed higher basal and ADP-stimulated respiration rates when Malate + Palmitoyl-L-carnitine were used as substrates. HFD did not alter ROS production and markers of mitochondrial content. The expression of CPT1b was significantly increased in SOL and EDL of HFD rats. Although the expression of UCP3 was increased in SOL and EDL muscles from HFD rats, mitochondrial coupling efficiency was not altered. In SOL of HFD rats, the transcript levels of Mfn2 and Fis1 were significantly upregulated. The expression and content of proteins regulating mitochondrial dynamics was not modulated by HFD in the EDL. Finally, DRP1 protein content was increased by over fourfold in the SOL of HFD rats. Taken altogether, our findings show that exposing young animals to short-term HFD results in an increased capacity of skeletal muscle mitochondria to oxidize fatty acids, without altering ROS production, coupling efficiency, and mitochondrial content. Our results also highlight that the impact of HFD on mitochondrial dynamics appears to be muscle specific.

Asunto(s)

Respiración de la Célula , Dieta Alta en Grasa , Mitocondrias Musculares/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Animales , Ácidos Grasos/metabolismo , Glucólisis , Peroxidación de Lípido , Masculino , Dinámicas Mitocondriales , Músculo Esquelético/metabolismo , Ratas , Ratas Wistar , Proteína Desacopladora 3/metabolismo

RESUMEN

OBJECTIVE: Nicotinamide phosphoribosyl transferase (NAMPT) is the rate-limiting enzyme in the salvage pathway that produces nicotinamide adenine dinucleotide (NAD+), an essential co-substrate regulating a myriad of signaling pathways. We produced a mouse that overexpressed NAMPT in skeletal muscle (NamptTg) and hypothesized that NamptTg mice would have increased oxidative capacity, endurance performance, and mitochondrial gene expression, and would be rescued from metabolic abnormalities that developed with high fat diet (HFD) feeding. METHODS: Insulin sensitivity (hyperinsulinemic-euglycemic clamp) was assessed in NamptTg and WT mice fed very high fat diet (VHFD, 60% by kcal) or chow diet (CD). The aerobic capacity (VO2max) and endurance performance of NamptTg and WT mice before and after 7 weeks of voluntary exercise training (running wheel in home cage) or sedentary conditions (no running wheel) were measured. Skeletal muscle mitochondrial gene expression was also measured in exercised and sedentary mice and in mice fed HFD (45% by kcal) or low fat diet (LFD, 10% by kcal). RESULTS: NAMPT enzyme activity in skeletal muscle was 7-fold higher in NamptTg mice versus WT mice. There was a concomitant 1.6-fold elevation of skeletal muscle NAD+. NamptTg mice fed VHFD were partially protected against body weight gain, but not against insulin resistance. Notably, voluntary exercise training elicited a 3-fold higher exercise endurance in NamptTg versus WT mice. Mitochondrial gene expression was higher in NamptTg mice compared to WT mice, especially when fed HFD. Mitochondrial gene expression was higher in exercised NamptTg mice than in sedentary WT mice. CONCLUSIONS: Our studies have unveiled a fascinating interaction between elevated NAMPT activity in skeletal muscle and voluntary exercise that was manifest as a striking improvement in exercise endurance.

Asunto(s)

Citocinas/metabolismo , Músculo Esquelético/metabolismo , Nicotinamida Fosforribosiltransferasa/metabolismo , Consumo de Oxígeno , Condicionamiento Físico Animal , Animales , Citocinas/genética , Dieta Alta en Grasa , Ratones , Ratones Endogámicos C57BL , Mitocondrias/metabolismo , Músculo Esquelético/fisiología , NAD/metabolismo , Nicotinamida Fosforribosiltransferasa/genética