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2.
Life Sci ; 237: 116954, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31610192

RESUMO

Sirt3 enzyme and mitochondrial abnormality can be related to excess fatigue or muscular dysfunction in multiple sclerosis (MS).Ellagic acid (EA) has a mitochondrial protector, iron chelator, antioxidant, and axon regenerator in neurons.In this study the effect of EAon muscle dysfunction, its mitochondria, and Sirt3 enzyme incuprizone-induced model of MSwas examined. Demyelination was induced by a diet containing 0.2% w/w cuprizone (Cup) for 42 days and EA administered daily (5, 50, and 100 mg/kg P.O) either with or without cuprizone in mice. Behavioral tests were assessed, and muscle tissue markers ofoxidative stress, mitochondrial parameters, mitochondrial respiratory chain activity, the Sirt3 protein level, and Sirt3 expression were also determined. Luxol fast blue staining and the behavioral tests were performed toassess the implemented model. In Cup group an increased oxidative stress in their muscle tissues was observed. Also, muscle mitochondria exhibited mitochondria dysfunction, lowered mitochondrial respiratory chain activity, Sirt3 protein level, and Sirt3 expression.EA prevented most of these anomalous alterations. Sub-chronicEA co-treatment dose-dependently ameliorated behavioral and muscular impairment in mice that received Cup.EA can effectively protect muscle tissue against cuprizone-induced demeylination via the mitochondrial protection, oxidative stress prevention and Sirt3 overexpression.


Assuntos
Comportamento Animal/efeitos dos fármacos , Cuprizona/toxicidade , Doenças Desmielinizantes/tratamento farmacológico , Ácido Elágico/farmacologia , Mitocôndrias Musculares/efeitos dos fármacos , Doenças Musculares/prevenção & controle , Sirtuína 3/metabolismo , Animais , Quelantes/toxicidade , Doenças Desmielinizantes/induzido quimicamente , Doenças Desmielinizantes/metabolismo , Doenças Desmielinizantes/patologia , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias Musculares/metabolismo , Mitocôndrias Musculares/patologia , Estresse Oxidativo/efeitos dos fármacos
3.
Muscle Nerve ; 60(6): 769-778, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31495926

RESUMO

INTRODUCTION: Physical inactivity significantly contributes to loss of muscle mass and performance in bed-bound patients. Loss of skeletal muscle mitochondrial content has been well-established in muscle unloading models, but the underlying molecular mechanism remains unclear. We hypothesized that apparent unloading-induced loss of muscle mitochondrial content is preceded by increased mitophagy- and decreased mitochondrial biogenesis-signaling during the early stages of unloading. METHODS: We analyzed a comprehensive set of molecular markers involved in mitochondrial-autophagy, -biogenesis, -dynamics, and -content, in the gastrocnemius muscle of C57BL/6J mice subjected to 0- and 3-days hind limb suspension, and in biopsies from human vastus lateralis muscle obtained before and after 7 days of one-leg immobilization. RESULTS: In both mice and men, short-term skeletal muscle unloading results in molecular marker patterns indicative of increased receptor-mediated mitophagy and decreased mitochondrial biogenesis regulation, before apparent loss of mitochondrial content. DISCUSSION: These results emphasize the early-onset of skeletal muscle disuse-induced mitochondrial remodeling.


Assuntos
Elevação dos Membros Posteriores , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Biogênese de Organelas , Adolescente , Adulto , Animais , Moldes Cirúrgicos , Expressão Gênica , Humanos , Imobilização , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias Musculares/patologia , Músculo Esquelético/patologia , Músculo Quadríceps/metabolismo , Músculo Quadríceps/patologia , Suporte de Carga , Adulto Jovem
4.
Trials ; 20(1): 484, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31395096

RESUMO

BACKGROUND: African Americans have a disproportionate prevalence and incidence of type 2 diabetes compared with Caucasians. Recent evidence indicates that low cardiorespiratory fitness (CRF) level, an independent risk factor for type 2 diabetes, is also more prevalent in African Americans than Caucasians. Numerous studies in Caucasian populations suggest that vigorous exercise intensity may promote greater improvements in CRF and other type 2 diabetes risk factors (e.g., reduction of glucose/insulin levels, pulse wave velocity, and body fat) than moderate intensity. However, current evidence comparing health benefits of different aerobic exercise intensities on type 2 diabetes risk factors in African Americans is negligible. This is clinically important as African Americans have a greater risk for type 2 diabetes and are less likely to meet public health recommendations for physical activity than Caucasians. The purpose of the HI-PACE (High-Intensity exercise to Promote Accelerated improvements in CardiorEspiratory fitness) study is to evaluate whether high-intensity aerobic exercise elicits greater improvements in CRF, insulin action, and arterial stiffness than moderate-intensity exercise in African Americans. METHODS/DESIGN: A randomized controlled trial will be performed on overweight and obese (body mass index of 25-45 kg/m2) African Americans (35-65 years) (n = 60). Participants will be randomly assigned to moderate-intensity (MOD-INT) or high-intensity (HIGH-INT) aerobic exercise training or a non-exercise control group (CON) for 24 weeks. Supervised exercise will be performed at a heart rate associated with 45-55% and 70-80% of VO2 max in the MOD-INT and HIGH-INT groups, respectively, for an exercise dose of 600 metabolic equivalents of task (MET)-minutes per week (consistent with public health recommendations). The primary outcome is change in CRF. Secondary outcomes include change in insulin sensitivity (measured via an intravenous glucose tolerance test), skeletal muscle mitochondrial oxidative capacity (via near-infrared spectroscopy), skeletal muscle measurements (i.e., citrate synthase, COX IV, GLUT-4, CPT-1, and PGC1-α), arterial stiffness (via carotid-femoral pulse wave velocity), body fat, C-reactive protein, and psychological outcomes (quality of life/exercise enjoyment). DISCUSSION: The anticipated results of the HI-PACE study will provide vital information on the health effects of high-intensity exercise in African Americans. This study will advance health disparity research and has the potential to influence future public health guidelines for physical activity. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02892331 . Registered on September 8, 2016.


Assuntos
Aptidão Cardiorrespiratória , Exercício , Ensaios Clínicos Controlados Aleatórios como Assunto , Adulto , Afro-Americanos , Idoso , Humanos , Pessoa de Meia-Idade , Mitocôndrias Musculares/metabolismo , Consumo de Oxigênio , Rigidez Vascular
5.
Redox Biol ; 26: 101294, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31450104

RESUMO

Previous studies have shown a significant increase in the mitochondrial generation of hydrogen peroxide (H2O2) and other peroxides in recently denervated muscle fibers. The mechanisms for generation of these peroxides and how the muscle responds to these peroxides are not fully established. The aim of this work was to determine the effect of denervation on the muscle content of proteins that may contribute to mitochondrial peroxide release and the muscle responses to this generation. Denervation of the tibialis anterior (TA) and extensor digitorum longus (EDL) muscles in mice was achieved by surgical removal of a small section of the peroneal nerve prior to its entry into the muscle. An increase in mitochondrial peroxide generation has been observed from 7 days and sustained up to 21 days following denervation in the TA muscle fibers. This increased peroxide generation was reduced by incubation of skinned fibers with inhibitors of monoamine oxidases, NADPH oxidases or phospholipase A2 enzymes and the muscle content of these enzymes together with peroxiredoxin 6 were increased following denervation. Denervated muscle also showed significant adaptations in the content of several enzymes involved in the protection of cells against oxidative damage. Morphological analyses indicated a progressive significant loss of muscle mass in the TA muscle from 7 days up to 21 days following denervation due to fiber atrophy but without fiber loss. These results support the possibility that, at least initially, the increase in peroxide production may stimulate adaptations in an attempt to protect the muscle fibers, but that these processes are insufficient and the increased peroxide generation over the longer term may activate degenerative and atrophic processes in the denervated muscle fibers.


Assuntos
Denervação Muscular , Músculo Esquelético/inervação , Músculo Esquelético/metabolismo , Oxirredução , Animais , Dissulfeto de Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Transgênicos , Mitocôndrias Musculares/metabolismo , Proteínas Mitocondriais/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/patologia , Músculo Esquelético/patologia , Transporte Proteico
6.
Nat Commun ; 10(1): 3923, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31462679

RESUMO

Circadian disruption aggravates age-related decline and mortality. However, it remains unclear whether circadian enhancement can retard aging in mammals. We previously reported that the small molecule Nobiletin (NOB) activates ROR (retinoid acid receptor-related orphan receptor) nuclear receptors to potentiate circadian oscillation and protect against metabolic dysfunctions. Here we show that NOB significantly improves metabolic fitness in naturally aged mice fed with a regular diet (RD). Furthermore, NOB enhances healthy aging in mice fed with a high-fat diet (HF). In HF skeletal muscle, the NOB-ROR axis broadly activates genes for mitochondrial respiratory chain complexes (MRCs) and fortifies MRC activity and architecture, including Complex II activation and supercomplex formation. These mechanisms coordinately lead to a dichotomous mitochondrial optimization, namely increased ATP production and reduced ROS levels. Together, our study illustrates a focal mechanism by a clock-targeting pharmacological agent to optimize skeletal muscle mitochondrial respiration and promote healthy aging in metabolically stressed mammals.


Assuntos
Envelhecimento/efeitos dos fármacos , Antioxidantes/farmacologia , Flavonas/farmacologia , Mitocôndrias Musculares/efeitos dos fármacos , Músculo Esquelético/metabolismo , Envelhecimento/metabolismo , Animais , Linhagem Celular , Dieta Hiperlipídica , Complexo de Proteínas da Cadeia de Transporte de Elétrons/genética , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias Musculares/metabolismo , Membro 1 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo
7.
Arch Insect Biochem Physiol ; 102(1): e21595, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31276240

RESUMO

Honey bees Apis mellifera L. are one of the most studied insect species due to their economic importance. The interest in studying honey bees chiefly stems from the recent rapid decrease in their world population, which has become a problem of food security. Nevertheless, there are no systemic studies on the properties of the mitochondria of honey bee flight muscles. We conducted a research of the mitochondria of the flight muscles of A. mellifera L. The influence of various organic substrates on mitochondrial respiration in the presence or absence of adenosine diphosphate (ADP) was investigated. We demonstrated that pyruvate is the optimal substrate for the coupled respiration. A combination of pyruvate and glutamate is required for the maximal respiration rate. We also show that succinate oxidation does not support the oxidative phosphorylation and the generation of membrane potential. We also studied the production of reactive oxygen species by isolated mitochondria. The greatest production of H2 O2 (as a percentage of the rate of oxygen consumed) in the absence of ADP was observed during the respiration supported by α-glycerophosphate, malate, and a combination of malate with another NAD-linked substrate. We showed that honey bee flight muscle mitochondria are unable to uptake Ca2+ -ions. We also show that bee mitochondria are able to oxidize the respiration substrates effectively at the temperature of 50°Ð¡ compared to Bombus terrestris mitochondria, which were more adapted to lower temperatures.


Assuntos
Abelhas/metabolismo , Mitocôndrias Musculares/metabolismo , Animais , Cálcio/metabolismo , Respiração Celular , Feminino , Voo Animal , Peróxido de Hidrogênio/metabolismo , Masculino , Potenciais da Membrana , Camundongos , Músculos/metabolismo , Temperatura Ambiente
8.
Elife ; 82019 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-31305240

RESUMO

Metabolic cycles are a fundamental element of cellular and organismal function. Among the most critical in higher organisms is the Cori Cycle, the systemic cycling between lactate and glucose. Here, skeletal muscle-specific Mitochondrial Pyruvate Carrier (MPC) deletion in mice diverted pyruvate into circulating lactate. This switch disinhibited muscle fatty acid oxidation and drove Cori Cycling that contributed to increased energy expenditure. Loss of muscle MPC activity led to strikingly decreased adiposity with complete muscle mass and strength retention. Notably, despite decreasing muscle glucose oxidation, muscle MPC disruption increased muscle glucose uptake and whole-body insulin sensitivity. Furthermore, chronic and acute muscle MPC deletion accelerated fat mass loss on a normal diet after high fat diet-induced obesity. Our results illuminate the role of the skeletal muscle MPC as a whole-body carbon flux control point. They highlight the potential utility of modulating muscle pyruvate utilization to ameliorate obesity and type 2 diabetes.


Assuntos
Glucose/metabolismo , Redes e Vias Metabólicas , Mitocôndrias Musculares/metabolismo , Células Musculares/metabolismo , Músculo Esquelético/metabolismo , Ácido Pirúvico/metabolismo , Magreza , Adiposidade , Animais , Proteínas de Transporte de Ânions/deficiência , Deleção de Genes , Lactatos/metabolismo , Camundongos , Camundongos Knockout , Proteínas de Transporte da Membrana Mitocondrial/deficiência , Transportadores de Ácidos Monocarboxílicos/deficiência , Força Muscular
9.
Metabolism ; 98: 53-61, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31226353

RESUMO

Peroxisomes are essential for lipid metabolism and disruption of liver peroxisomal function results in neonatal death. Little is known about how peroxisomal content and activity respond to changes in the lipid environment in human skeletal muscle (HSkM). AIMS: We hypothesized and tested that increased peroxisomal gene/protein expression and functionality occur in HSkM as an adaptive response to lipid oversupply. MATERIALS AND METHODS: HSkM biopsies, derived from a total of sixty-two subjects, were collected for 1) examining correlations between peroxisomal proteins and intramyocellular lipid content (IMLC) as well as between peroxisomal functionality and IMLC, 2) assessing peroxisomal gene expression in response to acute- or 7-day high fat meal (HFM), and in human tissue derived primary myotubes for 3) treating with high fatty acids to induce peroxisomal adaptions. IMLC were measured by both biochemical analyses and fluorescent staining. Peroxisomal membrane protein PMP70 and biogenesis gene (PEX) expression were assessed using western blotting and realtime qRT-PCR respectively. 1-14C radiolabeled lignocerate and palmitate oxidation assays were performed for peroxisomal and mitochondrial functionality respectively. RESULTS: 1) Under fasting conditions, HSkM tissue demonstrated a significant correlation (P ≪ 0.05) between IMCL and the peroxisomal biogenesis factor 19 (PEX19) protein as well as between lipid content and palmitate and lignocerate complete oxidation. 2) Similarly, post-HFM, additional PEX genes (Pex19, PEX11A, and PEX5) were significantly (P ≪ 0.05) upregulated. 3) Increments in PMP70, carnitine octanoyl transferase (CrOT), PGC-1α, and ERRα mRNA were observed post-fatty acid incubation in HSkM cells. PMP70 protein was significantly (P ≪ 0.05) elevated 48-h post lipid treatment. CONCLUSIONS: These results are the first to associate IMLC with peroxisomal gene/protein expression and function in HSkM suggesting an adaptive role for peroxisomes in lipid metabolism in this tissue.


Assuntos
Dieta Hiperlipídica , Expressão Gênica/fisiologia , Músculo Esquelético/metabolismo , Peroxissomos/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Adolescente , Adulto , Biópsia , Ácidos Graxos/metabolismo , Feminino , Humanos , Metabolismo dos Lipídeos/genética , Metabolismo dos Lipídeos/fisiologia , Masculino , Pessoa de Meia-Idade , Mitocôndrias Musculares/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Endopeptidase Neutra Reguladora de Fosfato PHEX/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Peroxissomos/genética , Cultura Primária de Células , Adulto Jovem
10.
Eur J Appl Physiol ; 119(8): 1799-1808, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31177324

RESUMO

PURPOSE: The recovery of muscle oxygen consumption (m[Formula: see text]O2) after exercise provides a measure of skeletal muscle mitochondrial capacity, as more and better-functioning mitochondria will be able to restore m[Formula: see text]O2 faster to the pre-exercise state. The aim was to measure muscle mitochondrial capacity using near-infrared spectroscopy (NIRS) within a healthy, normally active population and relate this to parameters of aerobic fitness, investigating the applicability and relevance of using NIRS to assess muscle mitochondrial capacity non-invasively. METHODS: Mitochondrial capacity was analysed in the gastrocnemius and flexor digitorum superficialis (FDS) muscles of eight relatively high-aerobic fitness ([Formula: see text]O2peak ≥ 57 mL/kg/min) and eight relatively low-aerobic fitness male subjects ([Formula: see text]O2peak ≤ 47 mL/kg/min). Recovery of whole body [Formula: see text]O2, i.e. excess post-exercise oxygen consumption (EPOC) was analysed after a cycling protocol. RESULTS: Mitochondrial capacity, as analysed using NIRS, was significantly higher in high-fitness individuals compared to low-fitness individuals in the gastrocnemius, but not in the FDS (p = 0.0036 and p = 0.20, respectively). Mitochondrial capacity in the gastrocnemius was significantly correlated with [Formula: see text]O2peak (R2 = 0.57, p = 0.0019). Whole body [Formula: see text]O2 recovery was significantly faster in the high-fitness individuals (p = 0.0048), and correlated significantly with mitochondrial capacity in the gastrocnemius (R2 = 0.34, p = 0.028). CONCLUSION: NIRS measurements can be used to assess differences in mitochondrial muscle oxygen consumption within a relatively normal, healthy population. Furthermore, mitochondrial capacity correlated with parameters of aerobic fitness ([Formula: see text]O2peak and EPOC), emphasising the physiological relevance of the NIRS measurements.


Assuntos
Exercício , Mitocôndrias Musculares/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Adolescente , Adulto , Humanos , Masculino , Consumo de Oxigênio , Aptidão Física , Espectroscopia de Luz Próxima ao Infravermelho/normas
11.
Int J Mol Sci ; 20(11)2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31163574

RESUMO

The sirtuins form a family of evolutionarily conserved nicotinamide adenine dinucleotide (NAD)-dependent deacetylases. Seven sirtuins (SIRT1-SIRT7) have been described in mammals, with specific intracellular localization and biological functions associated with mitochondrial energy homeostasis, antioxidant activity, proliferation and DNA repair. Physical exercise affects the expression of sirtuin in skeletal muscle, regulating changes in mitochondrial biogenesis, oxidative metabolism and the cellular antioxidant system. In this context, sirtuin 1 and sirtuin 3 have been the most studied. This review focuses on the effects of different types of exercise on these sirtuins, the molecular pathways involved and the biological effect that is caused mainly in healthy subjects. The reported findings suggest that an acute load of exercise activates SIRT1, which in turn activates biogenesis and mitochondrial oxidative capacity. Additionally, several sessions of exercise (training) activates SIRT1 and also SIRT3 that, together with the biogenesis and mitochondrial oxidative function, jointly activate ATP production and the mitochondrial antioxidant function.


Assuntos
Exercício , Mitocôndrias Musculares/genética , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/fisiologia , Sirtuínas/genética , Sirtuínas/metabolismo , Animais , Biomarcadores , Metabolismo Energético , Regulação da Expressão Gênica , Humanos , Transdução de Sinais
12.
Toxicol Mech Methods ; 29(8): 561-568, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31161845

RESUMO

Cleistanthus collinus is a poisonous shrub used for deliberate self-harm in rural areas of South India and intake of boiled decoction of leaves is a common method of self-harm. Distal renal tubular acidosis (dRTA) is an important clinical symptom observed in C. collinus poisoning, and renal V-ATPases may be potential targets of damage. However, a lack of understanding of molecular mediators involved hampers medical management, which is mainly supportive. We hypothesized that C. collinus poisoning induces renal oxidative stress; probably by inducing mitochondrial uncoupling, which compromises V-ATPase activity to ultimately produce dRTA. This was tested by exposing renal BBMV, kidney cells in culture, and Wistar rats to C. collinus poisoning. Exposure to C. collinus aqueous extract resulted in significant elevations in the lipid peroxidation marker, conjugated dienes, in cell culture and in vivo. A significant decrease in mitochondrial respiratory control ratio was observed in kidneys from C. collinus-treated animals suggesting that mitochondrial oxidative phosphorylation is uncoupled. This was accompanied by significant increase in ADP levels and a decrease in proton pump activity. Thus, these results demonstrate that C. collinus poisoning induces oxidative stress which influences proton pump activity, probably due to feedback inhibition by elevated ADP levels because of mitochondrial dysfunction in the rat kidney.


Assuntos
Acidose Tubular Renal/induzido quimicamente , Euphorbiaceae/envenenamento , Rim/efeitos dos fármacos , Mitocôndrias Musculares/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , ATPases Vacuolares Próton-Translocadoras/metabolismo , Acidose Tubular Renal/metabolismo , Animais , Feminino , Células HEK293 , Humanos , Rim/metabolismo , Rim/patologia , Masculino , Mitocôndrias Musculares/metabolismo , Fosforilação Oxidativa , Extratos Vegetais/envenenamento , Ratos Wistar
13.
Am J Physiol Endocrinol Metab ; 317(2): E374-E387, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31211616

RESUMO

Mitochondria are dynamic organelles with diverse functions in tissues such as liver and skeletal muscle. To unravel the mitochondrial contribution to tissue-specific physiology, we performed a systematic comparison of the mitochondrial proteome and lipidome of mice and assessed the consequences hereof for respiration. Liver and skeletal muscle mitochondrial protein composition was studied by data-independent ultra-high-performance (UHP)LC-MS/MS-proteomics, and lipid profiles were compared by UHPLC-MS/MS lipidomics. Mitochondrial function was investigated by high-resolution respirometry in samples from mice and humans. Enzymes of pyruvate oxidation as well as several subunits of complex I, III, and ATP synthase were more abundant in muscle mitochondria. Muscle mitochondria were enriched in cardiolipins associated with higher oxidative phosphorylation capacity and flexibility, in particular CL(18:2)4 and 22:6-containing cardiolipins. In contrast, protein equipment of liver mitochondria indicated a shuttling of complex I substrates toward gluconeogenesis and ketogenesis and a higher preference for electron transfer via the flavoprotein quinone oxidoreductase pathway. Concordantly, muscle and liver mitochondria showed distinct respiratory substrate preferences. Muscle respired significantly more on the complex I substrates pyruvate and glutamate, whereas in liver maximal respiration was supported by complex II substrate succinate. This was a consistent finding in mouse liver and skeletal muscle mitochondria and human samples. Muscle mitochondria are tailored to produce ATP with a high capacity for complex I-linked substrates. Liver mitochondria are more connected to biosynthetic pathways, preferring fatty acids and succinate for oxidation. The physiologic diversity of mitochondria may help to understand tissue-specific disease pathologies and to develop therapies targeting mitochondrial function.


Assuntos
Metabolismo Energético/fisiologia , Fígado/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Músculo Esquelético/metabolismo , Proteoma/metabolismo , Animais , Feminino , Humanos , Fígado/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias Hepáticas/metabolismo , Mitocôndrias Musculares/metabolismo , Proteínas Mitocondriais/análise , Músculo Esquelético/química , Especificidade de Órgãos , Mapeamento de Peptídeos/métodos , Proteoma/análise
14.
Am J Physiol Endocrinol Metab ; 317(2): E327-E336, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31211618

RESUMO

High energy expenditure is reported in cystic fibrosis (CF) animal models and patients. Alterations in skeletal muscle oxidative capacity, fuel utilization, and the creatine kinase-phosphocreatine system suggest mitochondrial dysfunction. Studies were performed on congenic C57BL/6J and F508del (Cftrtm1kth) mice. Indirect calorimetry was used to measure gas exchange to evaluate aerobic capacity during treadmill exercise. The bioenergetic function of skeletal muscle subsarcolemmal (SSM) and interfibrillar mitochondria (IFM) was evaluated using an integrated approach combining measurement of the rate of oxidative phosphorylation by polarography and of electron transport chain activities by spectrophotometry. CF mice have reduced maximal aerobic capacity. In SSM of these mice, oxidative phosphorylation was impaired in the presence of complex I, II, III, and IV substrates except when glutamate was used as substrate. This impairment appeared to be caused by a defect in complex V activity, whereas the oxidative system of the electron transport chain was unchanged. In IFM, oxidative phosphorylation and electron transport chain activities were preserved, whereas complex V activity was reduced, in CF. Furthermore, creatine kinase activity was reduced in both SSM and IFM of CF skeletal muscle. The decreased complex V activity in SSM resulted in reduced oxidative phosphorylation, which could explain the reduced skeletal muscle response to exercise in CF mice. The decrease in mitochondrial creatine kinase activity also contributed to this poor exercise response.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/genética , Fibrose Cística/metabolismo , Metabolismo Energético/genética , Músculo Esquelético/metabolismo , Animais , Fibrose Cística/patologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CFTR , Camundongos Transgênicos , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/patologia , Fosforilação Oxidativa , Estresse Oxidativo/genética , Condicionamento Físico Animal/fisiologia , Deleção de Sequência
15.
Magn Reson Imaging ; 61: 239-246, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31173850

RESUMO

OBJECT: Dynamic in vivo31P-NMR spectroscopy in combination with Magnetic Resonance Imaging (MRI) was used to study muscle bioenergetics of boreal and Arctic scallops (Pecten maximus and Chlamys islandica) to test the hypothesis that future Ocean Warming and Acidification (OWA) will impair the performance of marine invertebrates. MATERIALS & METHODS: Experiments were conducted following the recommendations for studies of muscle bioenergetics in vertebrates. Animals were long-term incubated under different environmental conditions: controls at 0 °C for C. islandica and 15 °C for P. maximus under ambient PCO2 of 0.039 kPa, a warm exposure with +5 °C (5 °C and 20 °C, respectively) under ambient PCO2 (OW group), and a combined exposure to warmed acidified conditions (5 °C and 20 °C, 0.112 kPa PCO2, OWA group). Scallops were placed in a 4.7 T MR animal scanner and the energetic status of the adductor muscle was determined under resting conditions using in vivo31P-NMR spectroscopy. The surplus oxidative flux (Qmax) was quantified by recording the recovery of arginine phosphate (PLA) directly after moderate swimming exercise of the scallops. RESULTS: Measurements led to reproducible results within each experimental group. Under projected future conditions resting PLA levels (PLArest) were reduced, indicating reduced energy reserves in warming exposed scallops per se. In comparison to vertebrate muscle tissue surplus Qmax of scallop muscle was about one order of magnitude lower. This can be explained by lower mitochondrial contents and capacities in invertebrate than vertebrate muscle tissue. Warm exposed scallops showed a slower recovery rate of PLA levels (kPLA) and a reduced surplus Qmax. Elevated PCO2 did not affected PLA recovery further. CONCLUSION: Dynamic in vivo31P-NMR spectroscopy revealed constrained residual aerobic power budgets in boreal and Arctic scallops under projected ocean warming and acidification indicating that scallops are susceptible to future climate change. The observed reduction in muscular PLArest of scallops coping with a warmer and acidified ocean may be linked to an enhanced energy demand and reduced oxygen partial pressures (PO2) in their body fluids. Delayed recovery from moderate swimming at elevated temperature is a result of reduced PLArest concentrations associated with a warm-induced reduction of a residual aerobic power budget.


Assuntos
Metabolismo Energético , Espectroscopia de Ressonância Magnética , Músculo Esquelético/metabolismo , Pectinidae/fisiologia , Algoritmos , Animais , Invertebrados , Mitocôndrias Musculares/metabolismo , Oceanos e Mares , Fósforo , Natação , Temperatura Ambiente
16.
Cell Mol Life Sci ; 76(24): 4887-4904, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31101940

RESUMO

Sustained nutrient (fuel) excess, as occurs during obesity and diabetes, has been linked to increased inflammation, impaired mitochondrial homeostasis, lipotoxicity, and insulin resistance in skeletal muscle. Precisely how mitochondrial dysfunction is initiated and whether it contributes to insulin resistance in this tissue remains a poorly resolved issue. Herein, we examine the contribution that an increase in proinflammatory NFkB signalling makes towards regulation of mitochondrial bioenergetics, morphology, and dynamics and its impact upon insulin action in skeletal muscle cells subject to chronic fuel (glucose and palmitate) overloading. We show sustained nutrient excess of L6 myotubes promotes activation of the IKKß-NFkB pathway (as judged by a six-fold increase in IL-6 mRNA expression; an NFkB target gene) and that this was associated with a marked reduction in mitochondrial respiratory capacity (>50%), a three-fold increase in mitochondrial fragmentation and 2.5-fold increase in mitophagy. Under these circumstances, we also noted a reduction in the mRNA and protein abundance of PGC1α and that of key mitochondrial components (SDHA, ANT-1, UCP3, and MFN2) as well as an increase in cellular ROS and impaired insulin action in myotubes. Strikingly, pharmacological or genetic repression of NFkB activity ameliorated disturbances in mitochondrial respiratory function/morphology, attenuated loss of SDHA, ANT-1, UCP3, and MFN2 and mitigated the increase in ROS and the associated reduction in myotube insulin sensitivity. Our findings indicate that sustained oversupply of metabolic fuel to skeletal muscle cells induces heightened NFkB signalling and that this serves as a critical driver for disturbances in mitochondrial function and morphology, redox status, and insulin signalling.


Assuntos
Metabolismo Energético/genética , Inflamação/genética , Mitocôndrias Musculares/metabolismo , NF-kappa B/genética , Nutrientes/metabolismo , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Glucose/metabolismo , Humanos , Inflamação/metabolismo , Inflamação/patologia , Insulina/metabolismo , Resistência à Insulina/genética , Mitocôndrias Musculares/genética , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , NF-kappa B/metabolismo , Obesidade/genética , Obesidade/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Transdução de Sinais/genética
17.
G Ital Nefrol ; 36(2)2019 Apr.
Artigo em Italiano | MEDLINE | ID: mdl-30983179

RESUMO

Fatty acid oxidation disorders are inborn errors of metabolism. One of the possible alterations involves the failure of the carnitin-based transport of long-chain fatty acids into the mitochondria, necessary for muscle metabolism in case of prolonged physical exertion. Three kinds of Carnitin-Palmitoyl Transferase type 2 (CPT2) deficiency have been described: a myopathic form, a severe infantile form and a neonatal form. The clinical picture is characterized by recurrent attacks of rhabdomyolysis, muscular pains and fatigue, secondary to a prolonged physical exercise and sometimes aggravated by intercurrent events. Rhabdomyolysis episodes are associated with a significant increase in creatine phosphokinase and myoglobinuria and may result in acute renal failure. Patients are usually asymptomatic during intercurrent periods. When acute renal failure from rhabdomyolysis arises after intense physical activity, it is therefore necessary to also investigate the presence of metabolic myopathies due to enzymatic deficiency.


Assuntos
Lesão Renal Aguda/etiologia , Carnitina O-Palmitoiltransferase/deficiência , Esforço Físico , Rabdomiólise/complicações , Lesão Renal Aguda/terapia , Creatina Quinase/metabolismo , Fadiga/etiologia , Ácidos Graxos/metabolismo , Hidratação , Humanos , Masculino , Mitocôndrias Musculares/metabolismo , Mialgia/etiologia , Mioglobinúria/complicações , Recidiva , Adulto Jovem
18.
Redox Biol ; 24: 101188, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30959461

RESUMO

OBJECTIVE: Reactive oxygen species (ROS) have been proposed as signaling molecules mediating exercise training adaptation, but the ROS source has remained unclear. This study aimed to investigate if increased NADPH oxidase (NOX)2-dependent activity during exercise is required for long-term high-intensity interval training (HIIT) in skeletal muscle using a mouse model lacking functional NOX2 complex due to absent p47phox (Ncf1) subunit expression (ncf1* mutation). METHODS: HIIT was investigated after an acute bout of exercise and after a chronic intervention (3x/week for 6 weeks) in wild-type (WT) vs. NOX2 activity-deficient (ncf1*) mice. NOX2 activation during HIIT was measured using an electroporated genetically-encoded biosensor. Immunoblotting and single-fiber microscopy was performed to measure classical exercise-training responsive endpoints in skeletal muscle. RESULTS: A single bout of HIIT increased NOX2 activity measured as p47-roGFP oxidation immediately after exercise but not 1 h or 4 h after exercise. After a 6-week HIIT regimen, improvements in maximal running capacity and some muscle training-markers responded less to HIIT in the ncf1* mice compared to WT, including superoxide dismutase 2, catalase, hexokinase II, pyruvate dehydrogenase and protein markers of mitochondrial oxidative phosphorylation complexes. Strikingly, HIIT-training increased mitochondrial network area and decreased fragmentation in WT mice only. CONCLUSION: This study suggests that HIIT exercise increases NOX2 activity in skeletal muscle and shows that NOX2 activity is required for specific skeletal muscle adaptations to HIIT relating to antioxidant defense, glucose metabolism, and mitochondria.


Assuntos
Adaptação Fisiológica , Treinamento Intervalado de Alta Intensidade , Músculo Esquelético/fisiologia , NADPH Oxidase 2/metabolismo , Animais , Humanos , Camundongos , Camundongos Knockout , Mitocôndrias Musculares/genética , Mitocôndrias Musculares/metabolismo , Mutação , NADPH Oxidase 2/genética , Oxirredução , Fosforilação , Espécies Reativas de Oxigênio
19.
Artigo em Inglês | MEDLINE | ID: mdl-30935113

RESUMO

In rodent skeletal muscle, acyl-coenzyme A (CoA) synthetase 5 (ACSL-5) is suggested to localize to the mitochondria but its precise function in human skeletal muscle is unknown. The purpose of these studies was to define the role of ACSL-5 in mitochondrial fatty acid metabolism and the potential effects on insulin action in human skeletal muscle cells (HSKMC). Primary myoblasts isolated from vastus lateralis (obese women (body mass index (BMI) = 34.7 ± 3.1 kg/m²)) were transfected with ACSL-5 plasmid DNA or green fluorescent protein (GFP) vector (control), differentiated into myotubes, and harvested (7 days). HSKMC were assayed for complete and incomplete fatty acid oxidation ([1-14C] palmitate) or permeabilized to determine mitochondrial respiratory capacity (basal (non-ADP stimulated state 4), maximal uncoupled (carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP)-linked) respiration, and free radical (superoxide) emitting potential). Protein levels of ACSL-5 were 2-fold higher in ACSL-5 overexpressed HSKMC. Both complete and incomplete fatty acid oxidation increased by 2-fold (p < 0.05). In permeabilized HSKMC, ACSL-5 overexpression significantly increased basal and maximal uncoupled respiration (p < 0.05). Unexpectedly, however, elevated ACSL-5 expression increased mitochondrial superoxide production (+30%), which was associated with a significant reduction (p < 0.05) in insulin-stimulated p-Akt and p-AS160 protein levels. We concluded that ACSL-5 in human skeletal muscle functions to increase mitochondrial fatty acid oxidation, but contrary to conventional wisdom, is associated with increased free radical production and reduced insulin signaling.


Assuntos
Coenzima A Ligases/metabolismo , Ácidos Graxos/metabolismo , Insulina/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Transdução de Sinais , Células Cultivadas , Feminino , Radicais Livres/metabolismo , Humanos , Metabolismo dos Lipídeos , Mitocôndrias Musculares/metabolismo , Obesidade/metabolismo , Oxirredução
20.
Arch Biochem Biophys ; 666: 52-62, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30935885

RESUMO

Over two thousand proteins are found in the mitochondrial compartment but the mitochondrial genome codes for only 13 proteins. The majority of mitochondrial proteins are products of nuclear genes and are synthesized in the cytosol, then translocated into the mitochondria. Most of the subunits of the five respiratory chain complexes in the inner mitochondrial membrane, which generate a proton gradient across the membrane and produce ATP, are encoded by nuclear genes. Therefore, it is quite clear that import of nuclear-encoded proteins into the mitochondria is essential for mitochondrial function. Nuclear to mitochondrial communication is well studied. However, there is another arm to this communication, mitochondria to nucleus retrograde signaling. This plays an important role in the maintenance of cellular homeostasis, and is less well studied. Several transcription factors, including Sp1, SIRT3 and GSP2, are activated by altered mitochondrial function. These activated transcription factors then translocate to the nucleus. Based on the mitochondrially generated molecular signal, nuclear genes are targeted, which alters transcription of nuclear genes that code for mitochondrial proteins. This review article will mainly focus on this interactive and bi-directional communication between mitochondria and nucleus, and how this communication plays a significant role in muscle cell biology.


Assuntos
Núcleo Celular/metabolismo , Mitocôndrias Musculares/metabolismo , Músculos/citologia , Animais , Sinalização do Cálcio , Homeostase , Humanos , Proteínas Mitocondriais/metabolismo , Músculos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
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