RESUMO
Aim Investigate whether inheritance of improved skeletal muscle mitochondrial function and its association with glycemic control are multigenerational benefits of exercise. MAIN METHODS: Male Swiss mice were subjected to 8 weeks of endurance training and mated with untrained females. KEY FINDINGS: Trained fathers displayed typical endurance training-induced adaptations. Remarkably, offspring from trained fathers also exhibited higher endurance performance, mitochondrial oxygen consumption, glucose tolerance and insulin sensitivity. However, PGC-1α expression was not increased in the offspring. In the offspring, the expression of the co-repressor NCoR1 was reduced, increasing activation of PGC-1α target genes. These effects correlated with higher DNA methylation at the NCoR1 promoter in both, the sperm of trained fathers and in the skeletal muscle of their offspring. SIGNIFICANCE: Higher skeletal muscle mitochondrial function is inherited by epigenetic de-activation of a key PGC-1α co-repressor.
Assuntos
Mitocôndrias/metabolismo , Condicionamento Físico Animal/fisiologia , Esforço Físico/fisiologia , Animais , Metilação de DNA , Epigênese Genética/genética , Feminino , Masculino , Camundongos , Mitocôndrias/fisiologia , Músculo Esquelético/fisiologia , Correpressor 1 de Receptor Nuclear/metabolismo , Consumo de Oxigênio/fisiologia , Herança Paterna/fisiologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/fisiologia , Condicionamento Físico Animal/métodos , RNA Mensageiro/genéticaRESUMO
The role of microRNAs in metabolic diseases has been recognized and modulation of them could be a promising strategy to treat obesity and obesity-related diseases. The major purpose of this study was to test the hypothesis that intramuscular miR-1 precursor replacement therapy could improve metabolic parameters of mice fed a high-fat diet. To this end, we first injected miR-1 precursor intramuscularly in high-fat diet-fed mice and evaluated glucose tolerance, insulin sensitivity, and adiposity. miR-1-treated mice did not lose weight but had improved insulin sensitivity measured by insulin tolerance test. Next, using an in vitro model of insulin resistance by treating C2C12 cells with palmitic acid (PA), we overexpressed miR-1 and measured p-Akt content and the transcription levels of a protein related to fatty acid oxidation. We found that miR-1 could not restore insulin sensitivity in C2C12 cells, as indicated by p-Akt levels and that miR-1 increased expression of Pgc1a and Cpt1b in PA-treated cells, suggesting a possible role of miR-1 in mitochondrial respiration. Finally, we analyzed mitochondrial oxygen consumption in primary skeletal muscle cells treated with PA and transfected with or without miR-1 mimic. PA-treated cells showed reduced basal respiration, oxygen consumption rate-linked ATP production, maximal and spare capacity, and miR-1 overexpression could prevent impairments in mitochondrial respiration. Our data suggest a role of miR-1 in systemic insulin sensitivity and a new function of miR-1 in regulating mitochondrial respiration in skeletal muscle.
RESUMO
Lin28a/miRNA let-7b-5p pathway has emerged as a key regulators of energy homeostasis in the skeletal muscle. However, the mechanism through which this pathway is regulated in the skeletal muscle has remained unclear. We have found that 8 wk of aerobic training (Tr) markedly decreased let-7b-5p expression in murine skeletal muscle, whereas high-fat diet (Hfd) increased its expression. Conversely, Lin28a expression, a well-known inhibitor of let-7b-5p, was induced by Tr and decreased by Hfd. Similarly, in human muscle biopsies, Tr increased LIN28 expression and decreased let-7b-5p expression. Bioinformatics analysis of LIN28a DNA sequence revealed that its enrichment in peroxisome proliferator-activated receptor delta (PPARδ) binding sites, which is a well-known metabolic regulator of exercise. Treatment of primary mouse skeletal muscle cells or C2C12 cells with PPARδ activators GW501516 and AICAR increased Lin28a expression. Lin28a and let-7b-5p expression was also regulated by PPARδ coregulators. While PPARγ coactivator-1α (PGC1α) increased Lin28a expression, corepressor NCoR1 decreased its expression. Furthermore, PGC1α markedly reduced the let-7b-5p expression. PGC1α-mediated induction of Lin28a expression was blocked by the PPARδ inhibitor GSK0660. In agreement, Lin28a expression was downregulated in PPARδ knocked-down cells leading to increased let-7b-5p expression. Finally, we show that modulation of the Lin28a-let-7b-5p pathway in muscle cells leads to changes in mitochondrial metabolism in PGC1α dependent fashion. In summary, we demonstrate that Lin28a-let-7b-5p is a direct target of PPARδ in the skeletal muscle, where it impacts mitochondrial respiration.
Assuntos
Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , PPAR delta/metabolismo , Proteínas de Ligação a RNA/genética , Animais , Linhagem Celular , Regulação para Baixo , Camundongos , Fibras Musculares Esqueléticas/metabolismo , PPAR delta/genéticaRESUMO
Pioglitazone belongs to the class of drugs thiazolidinediones (TZDs) and is an oral hypoglycemic drug, used in the treatment of type 2 diabetes, which improves insulin sensitivity in target tissues. Adipose tissue is the main target of pioglitazone, a PPARg and PPARa agonist; however, studies also point to skeletal muscle as a target. Non-PPAR targets of TZDs have been described, thus we aimed to study the direct effects of pioglitazone on skeletal muscle and the possible role of microRNAs as targets of this drug. Pioglitazone treatment of obese mice increased insulin-mediated glucose transport as a result of increased fatty acid oxidation and mitochondrial activity. PPARg blockage by treatment with GW9662 nullified pioglitazone's effect on systemic and muscle insulin sensitivity and citrate synthase activity of obese mice. After eight weeks of high-fat diet, miR-221-3p expression in soleus muscle was similar among the groups and miR-23b-3p and miR-222-3p were up-regulated in obese mice compared to the control group, and treatment with pioglitazone was able to reverse this condition. In vitro studies in C2C12 cells suggest that inhibition of miR-222-3p protects C2C12 cells from insulin resistance and increased non-mitochondrial respiration induced by palmitate. Together, these data demonstrate a role of pioglitazone in the downregulation of microRNAs that is not dependent on PPARg. Moreover, miR-222 may be a novel PPARg-independent mechanism through which pioglitazone improves insulin sensitivity in skeletal muscle.
Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , MicroRNAs/metabolismo , Músculo Esquelético/efeitos dos fármacos , Pioglitazona/farmacologia , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Glucose/metabolismo , Teste de Tolerância a Glucose , Hipoglicemiantes , Insulina/metabolismo , Resistência à Insulina/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Músculo Esquelético/metabolismo , Obesidade/tratamento farmacológico , Obesidade/metabolismo , PPAR alfa/metabolismo , PPAR gama/metabolismo , Palmitatos/farmacologia , Tiazolidinedionas/farmacologia , Regulação para Cima/efeitos dos fármacosRESUMO
Mitochondrial number and shape are constantly changing in response to increased energy demands. The ability to synchronize mitochondrial pathways to respond to energy fluctuations within the cell is a central aspect of mammalian homeostasis. This dynamic process depends on the coordinated activation of transcriptional complexes to promote the expression of genes encoding for mitochondrial proteins. Recent evidence has shown that the nuclear corepressor NCoR1 is an essential metabolic switch which acts on oxidative metabolism signaling. Here, we provide an overview of the emerging role of NCoR1 in the transcriptional control of energy metabolism. The identification and characterization of NCoR1 as a central, evolutionary conserved player in mitochondrial function have revealed a novel layer of metabolic control. Defining the precise mechanisms by which NCoR1 acts on energy homeostasis will ultimately contribute towards the development of novel therapies for the treatment of metabolic diseases such as obesity and type 2 diabetes.
Assuntos
Metabolismo Energético , Mitocôndrias/metabolismo , Correpressor 1 de Receptor Nuclear/metabolismo , Animais , Humanos , Correpressor 1 de Receptor Nuclear/química , Correpressor 1 de Receptor Nuclear/genética , PPAR alfa/genética , PPAR alfa/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Transdução de Sinais , Ativação Transcricional , Receptor ERRalfa Relacionado ao EstrogênioRESUMO
The aim of the present study was to evaluate the effects of aerobic exercise training on perivascular adipose tissue (PVAT) function in thoracic aorta from rats fed a high-fat diet. Aortic vascular reactivity was performed in sedentary (SD), trained (TR), sedentary high-fat diet (SD-HF), and trained high-fat diet (TR-HF) male Wistar rats in the absence (PVAT-) or in the presence (PVAT+) of thoracic PVAT. We also measured circulatory concentrations of leptin and tumour necrosis factor alpha (TNF-α), as well as the protein expressions of TNF-α receptor 1 (TNFR1) and inducible nitric oxide synthase (iNOS) on PVAT. In the SD-HF group, the body weight, epididymal fat pad, thoracic PVAT, circulatory triglycerides, insulin, leptin and TNF-α were increased when compared with the SD group, whereas exercise training reduced these values in TR-HF group. The relaxing response curves to acetylcholine and sodium nitroprusside were not modified by either intervention (high-fat diet or exercise training) or the presence of PVAT. The presence of PVAT had an anti-contractile effect in response to serotonin in all groups. In SD-HF group, the increased magnitude of anti-contractile effects was in parallel with an up-regulation of iNOS protein expression in PVAT without alteration in TNFR1. Exercise training was effective in normalizing the vascular reactivity in rings PVAT+ and in reducing the iNOS protein expression. Exercise training prevented the PVAT-induced alteration in thoracic aorta from rats fed a high-fat diet.
Assuntos
Tecido Adiposo/fisiologia , Aorta/fisiologia , Dieta Hiperlipídica/efeitos adversos , Condicionamento Físico Animal , Animais , Aorta/efeitos dos fármacos , Biomarcadores , Peso Corporal , Gorduras na Dieta , Epididimo/anatomia & histologia , Regulação da Expressão Gênica/efeitos dos fármacos , Masculino , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Ratos , Ratos Wistar , Receptores do Fator de Necrose Tumoral , Fator de Necrose Tumoral alfa/sangueRESUMO
The effect of fenofibrate on the metabolism of skeletal muscle and visceral white adipose tissue of diet-induced obese (DIO) mice was investigated. C57BL/6J male mice were fed either a control or high-fat diet for 8 weeks. Fenofibrate (50 mg/Kg BW, daily) was administered by oral gavage during the last two weeks of the experimental period. Insulin-stimulated glucose metabolism in soleus muscles, glucose tolerance test, insulin tolerance test, indirect calorimetry, lipolysis of visceral white adipose tissue, expression of miR-103-3p in adipose tissue, and miR-1a, miR-133a/b, miR-206, let7b-5p, miR-23b-3p, miR-29-3p, miR-143-3p in soleus muscle, genes related to glucose and fatty acid metabolism in adipose tissue and soleus muscle, and proteins (phospho-AMPKα2, Pgc1α, Cpt1b), intramuscular lipid staining, and activities of fatty acid oxidation enzymes in skeletal muscle were investigated. In DIO mice, fenofibrate prevented weight gain induced by HFD feeding by increasing energy expenditure; improved whole body glucose homeostasis, and in skeletal muscle, increased insulin dependent glucose uptake, miR-1a levels, reduced intramuscular lipid accumulation, and phospho-AMPKα2 levels. In visceral adipose tissue of obese mice, fenofibrate decreased basal lipolysis rate and visceral adipocytes hypertrophy, and induced the expression of Glut-4, Irs1, and Cav-1 mRNA and miR-103-3p suggesting a higher insulin sensitivity of the adipocytes. The evidence is presented herein that beneficial effects of fenofibrate on body weight, glucose homeostasis, and muscle metabolism might be related to its action in adipose tissue. Moreover, fenofibrate regulates miR-1a-3p in soleus and miR-103-3p in adipose tissue, suggesting these microRNAs might contribute to fenofibrate beneficial effects on metabolism.
Assuntos
Adipócitos/efeitos dos fármacos , Dieta Hiperlipídica , Fenofibrato/farmacologia , Hipolipemiantes/farmacologia , Músculo Esquelético/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Animais , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético/efeitos dos fármacos , Glucose/metabolismo , Resistência à Insulina/genética , Gordura Intra-Abdominal/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Músculo Esquelético/metabolismo , Obesidade/tratamento farmacológico , Obesidade/metabolismoRESUMO
BACKGROUND: The aim of the present study was to evaluate different signaling pathways by which exercise training would interfere in endothelial function in obesity. Therefore, we examined adipocytokine levels and their receptors in the corpus cavernosum and femoral artery from trained rats on a high-fat diet. METHODS: Functional experiments were performed in control sedentary and trained rats, and sedentary (h-SD) and trained male Wistar rats on a high-fat diet (h-TR). Nitric oxide (NO) and reactive oxygen species (ROS) were evaluated in vascular tissue. Circulating adipocytokines and their receptors were analyzed. RESULTS: In the h-SD group, the maximal responses to acetylcholine (ACh) were reduced in the femoral artery and corpus cavernosum as well as the electrical field stimulation, accompanied by an increase in circulating insulin, leptin, TNF-α, MCP-1, and PAI-1. Downregulation of ObR protein expression in the femoral artery was observed without alterations in AdipoR1 and TNFR1 in both preparations. A positive effect was observed in the h-TR group regarding the relaxation response to ACh and circulating adipocytokines, resulting in increased NO production and reduced ROS generation. Exercise restored the ObR protein expression only in the femoral artery. CONCLUSION: Aerobic exercise training ameliorated the inflammatory adipocytokines and restored the relaxation responses in the corpus cavernosum and femoral artery in rats on a high-fat diet.
Assuntos
Adipocinas/sangue , Dieta Hiperlipídica , Artéria Femoral/metabolismo , Pênis/irrigação sanguínea , Condicionamento Físico Animal , Receptores de Adipocina/metabolismo , Vasoconstrição , Vasodilatação , Animais , Relação Dose-Resposta a Droga , Estimulação Elétrica , Artéria Femoral/efeitos dos fármacos , Mediadores da Inflamação/sangue , Masculino , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Receptores de Adiponectina/metabolismo , Receptores para Leptina/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Comportamento Sedentário , Transdução de Sinais , Superóxido Dismutase/metabolismo , Vasoconstrição/efeitos dos fármacos , Vasoconstritores/farmacologia , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologiaRESUMO
Abstract The second messenger cGMP has been largely studied as a therapeutic target in a variety of disorders such as erectile dysfunction, arterial hypertension and heart failure. Evidence has shown thatcGMP activators are less efficient in estrogen-deficiency animals, but no studies exist involving non-pharmacological approacheson NO/cGMP signaling pathway in hypertensive postmenopausal women. The aim of this study is to examine NO/cGMP pathway, redox state and blood pressure in trained treatedhypertensive (HT) postmenopausal women comparing with normotensive (NT) group. The rationale for that is most of HT patients is encouraged by physician to perform exercise associated with pharmacological treatments.Aerobic exercise training (AET) consisted of 24 sessions, 3 times/week.Parameters were evaluated at baseline and after AET for both groups (HT=28; NT=33).In treatedHT group, AET was significantly effective in increasing cGMP concentrations (28%) accompanied by an up-regulation of SOD (97%) and catalase activity (37%). In NT group, we found an increasein SOD activity (58%). TreatedHT postmenopausal women were still responsive to AET increasing cGMP levels and up-regulating antioxidant system. It should also be emphasized that these findings provide information on the circulating biomarkers that might delay the developing of cardiovascular events in this particular population.(AU)
Assuntos
Humanos , Feminino , Pessoa de Meia-Idade , Idoso , GMP Cíclico/metabolismo , Exercício Físico , Hipertensão , Pós-Menopausa/fisiologiaRESUMO
Mitochondria play a critical role in several cellular processes and cellular homeostasis. Mitochondrion dysfunction has been correlated with numerous metabolic diseases such as obesity and type 2 diabetes. MicroRNAs are non-coding RNAs that have emerged as key regulators of cell metabolism. The microRNAs act as central regulators of metabolic gene networks by leading to the degradation of their target messenger RNA or repression of protein translation. In addition, vesicular and non-vesicular circulating miRNAs exhibit a potential role as mediators of the cross-talk between the skeletal muscle and other tissues/organs. In this review, we will focus on the emerging knowledge of miRNAs controlling mitochondrial function and insulin signaling in skeletal muscle cells. J. Cell. Physiol. 232: 958-966, 2017. © 2016 Wiley Periodicals, Inc.