Introdução: Entende-se o fenômeno mitocondrial de resposta a proteínas malformadas (UPRmt), como um sistema de controle e qualidade de proteínas que asseguram a integridade e funcionalidade das mitocôndrias frente a danos proteotóxicos.A UPRmt é induzida por um desequilíbrio estequiométrico entre proteínas codificadas pelo DNA mitocondrial (mtDNA), e proteínas oriundas do DNA nuclear (nDNA), ativando chaperonas e proteases que remodelam e asseguram a funcionalidade das proteínas mitocondriais, melhorando o metabolismo e suas funções.No entanto, durante o envelhecimento, a disfunção mitocondrial é, ao menos em parte, relacionada à redução da capacidade de ativação da UPRmt.Contudo, sabe-se que o exercício promove respostas fisiológicas benéficas frente a condições que provocam o declínio fisiológico, como a senescência celular.Dessa forma, é plausível ponderar que exercício pode induzir o desequilíbrio mitonuclear e a UPRmt, contrabalanceando a disfunção mitocondrial no envelhecimento.Materiais e Métodos: Camundongos C57BL/6J, com 2 meses (jovens) e 2 anos (idosos) foram utilizados.Os animais idosos foram submetidos a dois protocolos de exercício físico crônico: O primeiro [Estudo 1] com 60 minutos, em intensidade moderada.O segundo [Estudo 2] com 30 minutos, em bouts intervalados de alta intensidade (HIIT), ambos durante 4 semanas.Ao final das intervenções, combinamos análises fisiológicas e moleculares para avaliar os efeitos do treinamento sobre o desencadeamento do desequilíbrio mitonuclear, UPRmt e metabolismo mitocondrial no músculo esquelético de animais idosos.Por fim, análises de bioinformática foram realizadas utilizando bases de dados de camundongos e humanos idosos, associando genes da UPRmt com o metabolismo mitocondrial no tecido muscular e fatores fisiológicos.Resultados: O envelhecimento diminuiu marcadores da UPRmt no músculo esquelético de camundongos.Contudo, ambos os protocolos de exercício foram capazes de induzir o desequilíbrio mitonuclear e a ativação da UPRmt nos animais idosos.Em adição, ambos os protocolos aumentam o conteúdo mitocondrial na musculatura esquelética, além de aumentar a performance física.Análises de bioinformática corroboram os resultados, demonstrando correlações positivas entre genes da UPRmt e do metabolismo mitocondrial no musculo esquelético em camundongos e humanos.Conclusão: Em conjunto, os resultados evidenciam que a UPRmt é um mecanismo conservado de longevidade, e que o exercício físico é uma ferramenta não farmacológica altamente eficiente em induzir o desequilíbrio mitonuclear, a ativação da UPRmt e a funcionalidade mitocondrial na musculatura esquelética de camundongos idosos.

Dysfunction of the adipose tissue metabolism is considered as a significant hallmark of aging. It has been proposed that α-β hydrolase domain containing 5 (ABHD5) plays a critical role in the control of lipolysis. However, the role of ABHD5 in the control of lipolysis during aging or exercise is unknown. Here we combined the experimental mouse model with transcriptomic analyzes by using murine and human databases to explore the role of ABHD5 in the adipose tissue during aging and in response to exercise. Transcriptomic data revealed a downregulation of Abhd5 messenger RNA levels in the subcutaneous white adipose tissue (scWAT) over time in individuals from 20 to 69 years old. Aged mice displayed dramatic reduction of ABHD5 protein content and lipolytic-related proteins in the scWAT. Interestingly, 4 weeks of high-intensity interval training increased ABHD5 protein level and restored the lipolytic pathway in the scWAT of aged mice. Altogether, our findings demonstrated that aging affects ABHD5 content in the adipose tissue of mice and humans. Conversely, exercise increases ABHD5 activity, recovering the lipolytic activity in aged mice.

Acute metabolic and molecular response to exercise may vary according to exercise's intensity and duration. However, there is a lack regarding specific tissue alterations after acute exercise with aerobic or anaerobic predominance. The present study investigated the effects of acute exercise performed at different intensities, but with equal total load on molecular and physiological responses in swimming rats. Sixty male rats were divided into a control group and five groups performing an acute bout of swimming exercise at different intensities (80, 90, 100, 110 and 120% of anaerobic threshold [AnT]). The exercise duration of each group was balanced so all groups performed at the same total load. Gene expression (HIF-1α, PGC-1α, MCT1 and MCT4 mRNA), blood biomarkers and tissue glycogen depletion were analyzed after the exercise session. ANOVA One-Way was used to indicate statistical mean differences considering 5% significance level. Blood lactate concentration was the only biomarker sensitive to acute exercise, with a significant increase in rats exercised above AnT intensities (p < 0.000). Glycogen stores of gluteus muscle were significantly reduced in all exercised animals in comparison to control group (p = 0.02). Hepatic tissue presented significant reduction in glycogen in animals exercised above AnT (p = 0.000, as well as reduced HIF-1α mRNA and increased MCT1 mRNA, especially at the highest intensity (p = 0.002). Physiological parameters did not alter amongst groups for most tissues. Our results indicate the hepatic tissue alterations (glycogen stores and gene expressions) in response to different exercise intensities of exercise, even with the total load matched.

Caffeine is one of the most widely used substances as recreational drug for performance-enhancement in sport, underpinned by a strong evidence base. Although the effects of caffeine are widely investigated within the scope of performance physiology, the molecular effects of caffeine within skeletal muscle remain unclear. Evidence from in vitro and in vivo models suggest that caffeine regulates the glucose metabolism in the skeletal muscle. Moreover, caffeine seems to stimulate CaMKII, PPARδ/β, AMPK and PGC1α, classical markers of exercise-adaptations, including mitochondrial biogenesis and mitochondrial content. This review summarizes evidence to suggest caffeine-effects within skeletal muscle fibers, focusing on the putative role of caffeine on mitochondrial biogenesis to explore whether caffeine supplementation might be a strategy to enhance mitochondrial biogenesis.

The impairment of the mitochondrial functions is a hallmark of aging. During aging, there is a downregulation of two mechanisms strictly associated with mitochondrial integrity, including the mitonuclear imbalance (eg, imbalance in mitochondrial- versus nuclear-encoded mitochondrial proteins) and the mitochondrial unfolded protein response (UPRmt). Here, we evaluated the effects of aerobic exercise in the mitonuclear imbalance and UPRmt markers in the skeletal muscle of old mice. We combined the physiological tests, molecular and bioinformatic analyzes to evaluate the effects of 4 weeks of aerobic exercise training on mitonuclear imbalance and UPRmt markers in the skeletal muscle of young (2 months) and aged (24 months) C57BL/6J mice. Initially, we found that aging reduced several mitochondrial genes in the gastrocnemius muscle, and it was accompanied by the low levels of UPRmt markers, including Yme1l1 and Clpp mRNA. As expected, physical training improved the whole-body metabolism and physical performance of aged mice. The aerobic exercise increased key proteins involved in the mitochondrial biogenesis/functions (VDAC and SIRT1) along with mitochondrial-encoded genes (mtNd1, mtCytB, and mtD-Loop) in the skeletal muscle of old mice. Interestingly, aerobic exercise induced the mitonuclear imbalance, increasing MTCO1/ATP5a ratio and UPRmt markers in the skeletal muscle, including HSP60, Lonp1, and Yme1L1 protein levels in the gastrocnemius muscle of aged mice. These data demonstrate that aerobic exercise training induced mitonuclear imbalance and UPRmt in the skeletal muscle during aging. These phenomena could be involved in the improvement of the mitochondrial metabolism and oxidative capacity in aged individuals.

The impairment of mitochondrial metabolism is a hallmark of aging. Mitonuclear imbalance and the mitochondrial unfolded protein response (UPRmt) are two conserved mitochondrial mechanisms that play critical roles in ensuring mitochondrial proteostasis and function. Here, we combined bioinformatics, physiological, and molecular analyses to examine the role of mitonuclear imbalance and UPRmt in the skeletal muscle of aged rodents and humans. The analysis of transcripts from the skeletal muscle of aged humans (60–70 years old) revealed that individuals with higher levels of UPRmt-related genes displayed a consistent increase in several mitochondrial-related genes, including the OXPHOS-associated genes. Interestingly, high-intensity interval training (HIIT) was effective in stimulating the mitonuclear imbalance and UPRmt in the skeletal muscle of aged mice. Furthermore, these results were accompanied by higher levels of several mitochondrial markers and improvements in physiological parameters and physical performance. These data indicate that the maintenance or stimulation of the mitonuclear imbalance and UPRmt in the skeletal muscle could ensure mitochondrial proteostasis during aging, revealing new insights into targeting mitochondrial metabolism by using physical exercise.

This study investigated the effect of non-periodized training performed at 80, 100 and 120% of the anaerobic threshold intensity (AnT) and a linear periodized training model adapted for swimming rats on the gene expression of monocarboxylate transporters 1 and 4 (MCT1 and 4, in soleus and gastrocnemius muscles), protein contents, blood biomarkers, tissue glycogen, body mass, and aerobic and anaerobic capacities. Sixty Wistar rats were randomly divided into 6 groups (n = 10 per group): a baseline (BL; euthanized before training period), a control group (GC; not exercised during the training period), three groups exercised at intensities equivalent to 80, 100 and 120% of the AnT (G80, G100 and G120, respectively) at the equal workload and a linear periodized training group (GPE). Each training program lasted 12 weeks subdivided into three periods: basic mesocycle (6 weeks), specific mesocycle (5 weeks) and taper (1 week). Although G80, G100 and G120 groups were submitted to monotony workload (i.e. non-modulation at intensity or volume throughout the training program), rodents were evaluated during the same experimental timepoints as GPE to be able comparisons. Our main results showed that all training programs were capable to minimize the aerobic capacity decrease promoted by age, which were compared to control group. Rats trained in periodization model had reduced levels of lipid blood biomarkers and increased hepatic glycogen stores compared to all other trained groups. At the molecular level, only expressions of MCT1 in the muscle were modified by different training regimens, with MCT1 mRNA increasing in rats trained at lower intensities (G80), and MCT1 protein content showed higher values in non-periodized groups compared to pre-training and GPE. Here, training at different intensities but at same total workload promoted similar adaptations in rats. Nevertheless, our results suggested that periodized training seems to be optimize the physiological responses of rats.

A lipolise e um mecanismo biologico complexo responsavel por promover a degradacao de moleculas de gordura para obtencao de substrato energetico. O processo de envelhecimento e acompanhado pelo aumento do acumulo de tecido adiposo, que ocorre ao menos em parte, devido a reducao da capacidade de ativacao da lipolise. Por outro lado, sabidamente o exercicio fisico e reconhecido como um potente estimulador do processo da lipolise. Recentemente, a proteina ABHD5 (do ingles, α-β hidrolase domain-contain protein 5) foi descrita como molecula chave no controle da lipolise, ao passo que a interacao entre a ABHD5/ATGL e determinante para a metabolizacao de triglicerideos para obtencao de energia. Contudo pouco se conhece sobre a influencia do envelhecimento e do exercicio fisico sobre a expressao/atividade da ABHD5. Portanto o atual projeto pretende avaliar o efeito do envelhecimento sobre o conteudo proteico de ABHD5 no tecido adiposo de camundongos, bem como investigar o papel do exercicio fisico sobre a ABHD5 e a ativacao da lipolise em camundongos idosos. A realizacao do presente projeto podera ajudar a elucidar o papel da ABHD5 sobre o acumulo de gordura durante o envelhecimento, bem como determinar a possivel capacidade do exercicio fisico em modular a atividade da ABHD5 e da lipolise no envelhecimento.

Purpose Nicotinamide riboside (NR) acts as a potent NAD + precursor and improves mitochondrial oxidative capacity and mitochondrial biogenesis in several organisms. However, the effects of NR supplementation on aerobic performance remain unclear. Here, we evaluated the effects of NR supplementation on the muscle metabolism and aerobic capacity of sedentary and trained mice. Methods Male C57BL/6 J mice were supplemented with NR (400 mg/Kg/day) over 5 and 10 weeks. The training protocol consisted of 5 weeks of treadmill aerobic exercise, for 60 min a day, 5 days a week. Bioinformatic and physiological assays were combined with biochemical and molecular assays to evaluate the experimental groups. Results NR supplementation by itself did not change the aerobic performance, even though 5 weeks of NR supplementation increased NAD + levels in the skeletal muscle. However, combining NR supplementation and aerobic training increased the aerobic performance compared to the trained group. This was accompanied by an increased protein content of NMNAT3, the rate-limiting enzyme for NAD + biosynthesis and mitochondrial proteins, including MTCO1 and ATP5a. Interestingly, the transcriptomic analysis using a large panel of isogenic strains of BXD mice confirmed that the Nmnat3 gene in the skeletal muscle is correlated with several mitochondrial markers and with different phenotypes related to physical exercise. Finally, NR supplementation during aerobic training markedly increased the amount of type I fibers in the skeletal muscle. Conclusion Taken together, our results indicate that NR may be an interesting strategy to improve mitochondrial metabolism and aerobic capacity.

Sphingolipids were discovered more than a century ago and were simply considered as a class of cell membrane lipids for a long time. However, after the discovery of several intracellular functions and their role in the control of many physiological and pathophysiological conditions, these molecules have gained much attention. For instance, the sphingosine-1-phosphate (S1P) is a circulating bioactive sphingolipid capable of triggering strong intracellular reactions through the family of S1P receptors (S1PRs) spread in several cell types and tissues. Recently, the role of S1P in the control of skeletal muscle metabolism, atrophy, regeneration, and metabolic disorders has been widely investigated. In this review, we summarized the knowledge of S1P and its effects in skeletal muscle metabolism, highlighting the role of S1P/S1PRs axis in skeletal muscle regeneration, fatigue, ceramide accumulation, and insulin resistance. Finally, we discussed the physical exercise role in S1P/S1PRs signaling in skeletal muscle cells, and how this nonpharmacological strategy may be prospective for future investigations due to its ability to increase S1P levels.

We previously reported evidence about the positive effects of continuous aerobic training (CAT) in hypertensive obese people. We showed that 90 min/week of aerobic exercise on a treadmill (70%-80% of the Maximal Heart Rate [MHR]) was able to improve the systemic blood metabolism of obese subjects. Therefore, we believe that reducing the recommended amount of aerobic exercise (150 min/week) by American College of Sports Medicine (ACSM) is a valuable strategy to for sedentary individuals with pathological conditions, since the suggested protocol is easyto- perform, fast and enjoyable for the subjects. In this comment, we tempt to summarize the literature evidences regarding physical aerobic exercise on cardiac metabolism in hypertensive obese individuals. These findings may influence the consenting information over the prescription of physical activity for individuals with cardiac-associated pathologies.

The main objective of this study was to examine the effect of continuous aerobic training (CAT) in hypertensive, obese people. Seven patients of average age (45.3 +/- 3.9 years), height (1.63 +/- 0.1 m), body weight (89.09 +/- 22.0 kg), and body mass index (33.44 +/- 8.6 kg/m(2)) were subjected to the training. CAT was performed in thrice-weekly nonconsecutive sessions (90 min per week) with intervals of 48 hr between each session. The training sessions entailed 30 min of walking at an intensity of 70%-80% of the maximum heart rate (MHR) on a treadmill over a period of eight weeks, giving a total of 24 sessions. Through correlation analyses, we found significant improvement in the systolic pressure (R=0.5675, P=0.0253) and diastolic pressure (R=0.7083, P=0.0088) when the last session was compared to the first session of training. We found no differences in the diastolic pressure and systolic pressure before, during and after 15 min of the protocol exercise. The program showed a large effect size (ES) for systolic pressure (ES=0.85) and a small ES for diastolic pressure (ES=0.33). We found no differences in the blood pressure (BP) and heart rate (HR) during and after the training of obese hypertensive humans, but we found a positively significant correlation between HR and BP in the last session and a large ES, suggesting that this protocol exercise might have significance effect in the long term.

White adipose tissue (WAT) regulates energy homeostasis by releasing adipokines and modulating cell maintenance. Nutrient excess affects adipocyte hypertrophy directly in WAT by increasing excessively the activity of autophagy systems, generating proinflammatory markers and increasing infiltration of macrophages, causing metabolic diseases such as obesity and diabetes. Evidences suggest that cathepsin B (CTSB), a papain-like cysteine peptidase protein, can modulate autophagy processes in adipocytes. This review will focus on the role of CTSB in autophagy under conditions of obesity.

Sphingolipids were discovered more than a century ago and were simply considered as a class of cell membrane lipids for a long time. However, after the discovery of several intracellular functions and their role in the control of many physiological and pathophysiological conditions, these molecules have gained much attention. For instance, the sphingosine‐1‐phosphate (S1P) is a circulating bioactive sphingolipid capable of triggering strong intracellular reactions through the family of S1P receptors (S1PRs) spread in several cell types and tissues. Recently, the role of S1P in the control of skeletal muscle metabolism, atrophy, regeneration, and metabolic disorders has been widely investigated. In this review, we summarized the knowledge of S1P and its effects in skeletal muscle metabolism, highlighting the role of S1P/S1PRs axis in skeletal muscle regeneration, fatigue, ceramide accumulation, and insulin resistance. Finally, we discussed the physical exercise role in S1P/S1PRs signaling in skeletal muscle cells, and how this nonpharmacological strategy may be prospective for future investigations due to its ability to increase S1P levels.

Here we sought to determine the effect of S1P administration on physical performance and on AMPK and Akt phosphorylation in the muscle of mice. Methods: Mice were divided in four groups: Wild-Type, Placebo, Exercise and Exercise plus intramuscular S1P during 3 consecutive days. Thereafter, the animals performed an incremental exercise test. Results: We demonstrate a relation between S1P and physical exercise in response to markers of mitochondrial biogenesis. Immunoblotting analysis showed an increase in phosphorylation of AMPK and AKT in response to S1P administration. The placebo group ran significantly less in comparison to S1P and Exercised groups. Conclusions: These preliminary findings suggest that physical exercise and S1P may enhance oxidative metabolism in the skeletal muscle and performance in mice.

Sestrins and autophagy deficiencies are associated with several aging-related organic dysfunctions and metabolic disorders. Here we evaluate the effects of acute exercise on Sestrin 2 (Sesn2) protein content and autophagy markers in the skeletal muscle of experimental models of aging. Twenty-four months-old C57BL/6J male mice were submitted to a single bout of swimming exercise and the gastrocnemius muscle was evaluated by Western blot. Transcriptomic and phenotypic analysis were also performed by using strains of genetically-diverse BXD mice. The bioinformatics analysis showed a negative correlation between Sesn2 mRNA levels in the skeletal muscle and body weight gain, plasma triglycerides and fasting glucose and positive correlation with several autophagic markers in the muscle of BXD mice. Consistent with these findings, low levels of Sesn2 protein content were observed in the gastrocnemius muscle of C57BL/6J old mice when compared to young group. Interestingly, the acute aerobic exercise induced Sesn2 accumulation and modulated several markers of autophagy in the gastrocnemius muscle old mice, including unc-51-like kinase-1 (Ulk1) phosphorylation and the protein levels of Atg5, Atg7, p62 and LC3-II. Finally, exercise increased insulin sensitivity in old animals, as demonstrated by kITT. Taken together, these findings demonstrated the acutely, aerobic physical exercise recovers Sestrin 2 protein content and induces autophagy in the skeletal muscle of old mice, contributing with the improvement of insulin sensitivity an aging animal model.

PURPOSE: The hypothalamus controls the energy homeostasis integrating of hormonal and nutritional signals. In this context, glucose plays a critical role in the control of energy balance acting in specific hypothalamic neurons. It has been demonstrated that the lost selective of glucose sensibility in the hypothalamic neurons are related to the hyperphagia and obesity. Recently, the hypoxia-inducible factor 2 alpha (HIF2α) have emerged as regulated important in maintenance of glucose sensibility in hypothalamic neurons. In this context, the maintenance of neuronal HIF2α function can be considerate a determinate strategy for maintenance of lean phenotype. At the same time, the physical exercise is considered a main contributor to the control of body weight and energy expenditure. Thus, sought evaluate the effects of physical exercise on HIF2α protein levels and on glucose sensibility in the hypothalamus of rodents. METHODS:Physical exercise, Western blot and stereotaxic surgery were combined to explore HIF2a protein levels and hypothalamic glucose sensibility. The intracerebroventricular (ICV) injection of glucose was performed to measure the food intake and the quantification of HIF2α pathway in hypothalamus of both lean and obese (diet-induced obesity) male Wistar rats. For statistical analysis were used the ANOVA one-way. RESULTS:We observed the reduction of hypothalamic glucose sensitivity in obese mice, which was accompanied by a lower protein expression of HIF-2α, as well as reduction of prolyl hydroxylases (PHDs) and ubiquitin E3 ligase PVH, product Hippel-Lindau (VHL) gene, when compared to the control group. Interestingly, we found that the exercise restored hypothalamic of HIF-2α expression and glucose sensitivity in obese rats. CONCLUSIONS:Our preliminary results demonstrate that high-fat diet disrupts hypothalamic HIF-2α protein and affects the glucose sensitivity in neurons, contributing with hyperphagia. On the other hand, exercise increased HIF-2α protein levels in the hypothalamus and potentiated glucose sensitivity in obese rats, reducing the food intake.

High volume or high intensity exercises promotes different metabolic responses. However, the effects of isoload acute exercises at different manipulations of volume and intensity on metabolic parameters and muscle damage markers in rats are unknown. PURPOSE:To determine the metabolic effects of isoload efforts accomplished at different manipulations of volume and intensity (near anaerobic threshold) in swimming rats. Specifically, to verify the responses of serum parameters (glucose [GL], triglycerides [TG], high density lipoprotein [HDL], total protein [TP], albumin [AL], uric acid [UA], creatine-kinase [CK]) and glycogen content in gastrocnemius (GAG) and gluteus (GLG) muscles after exercises. METHODS:60 Wistar rats (90 days) performed a lactate minimum test to determine the individual anaerobic threshold (LM). Subsequently, rats were separated in 6 groups: control (GC), G80, G90, G100, G110 and G120 (exercised at 80 to 120% LM intensity, respectively). The exercise volume of each group was adjusted (from 2250 to 1500 seconds) to obtain the same workload (180,000 AU). Metabolic parameters were analyzed immediately after acute exercises. ANOVA one-way was used to compare responses among groups (P<0.05). RESULTS:LM intensity was 5.2±0.4 % of body mass. All metabolic parameters and muscle damage marker (CK) (table 1) were similar among groups. The UA of G120 was higher than in other groups, but this value was within the normal range for the exercise. CONCLUSIONS:At least near the LM, Isoload acute exercise at different intensities promoted similar metabolic responses in rats, suggesting a homeostasis maintenance during these efforts. In chronic exercises, these responses must still be investigated.Table 1: Results of serum and tissue parametes. * difference among others groups (P < 0.05).Supported by FAPESP (2014/10336-9 and 2009/08535-5), CAPES and CNPQ.