RESUMO
BACKGROUND: Cerebral glucose hypometabolism is consistently observed in individuals with Alzheimer's disease (AD), as well as in young cognitively normal carriers of the Ε4 allele of Apolipoprotein E (APOE), the strongest genetic predictor of late-onset AD. While this clinical feature has been described for over two decades, the mechanism underlying these changes in cerebral glucose metabolism remains a critical knowledge gap in the field. METHODS: Here, we undertook a multi-omic approach by combining single-cell RNA sequencing (scRNAseq) and stable isotope resolved metabolomics (SIRM) to define a metabolic rewiring across astrocytes, brain tissue, mice, and human subjects expressing APOE4. RESULTS: Single-cell analysis of brain tissue from mice expressing human APOE revealed E4-associated decreases in genes related to oxidative phosphorylation, particularly in astrocytes. This shift was confirmed on a metabolic level with isotopic tracing of 13C-glucose in E4 mice and astrocytes, which showed decreased pyruvate entry into the TCA cycle and increased lactate synthesis. Metabolic phenotyping of E4 astrocytes showed elevated glycolytic activity, decreased oxygen consumption, blunted oxidative flexibility, and a lower rate of glucose oxidation in the presence of lactate. Together, these cellular findings suggest an E4-associated increase in aerobic glycolysis (i.e. the Warburg effect). To test whether this phenomenon translated to APOE4 humans, we analyzed the plasma metabolome of young and middle-aged human participants with and without the Ε4 allele, and used indirect calorimetry to measure whole body oxygen consumption and energy expenditure. In line with data from E4-expressing female mice, a subgroup analysis revealed that young female E4 carriers showed a striking decrease in energy expenditure compared to non-carriers. This decrease in energy expenditure was primarily driven by a lower rate of oxygen consumption, and was exaggerated following a dietary glucose challenge. Further, the stunted oxygen consumption was accompanied by markedly increased lactate in the plasma of E4 carriers, and a pathway analysis of the plasma metabolome suggested an increase in aerobic glycolysis. CONCLUSIONS: Together, these results suggest astrocyte, brain and system-level metabolic reprogramming in the presence of APOE4, a 'Warburg like' endophenotype that is observable in young females decades prior to clinically manifest AD.
Assuntos
Aerobiose , Apolipoproteína E4/fisiologia , Glucose/metabolismo , Glicólise , Sintomas Prodrômicos , Adolescente , Adulto , Idoso , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Animais , Apolipoproteína E4/genética , Astrócitos/metabolismo , Sequência de Bases , Química Encefálica , Células Cultivadas , Diagnóstico Precoce , Metabolismo Energético , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Técnicas de Introdução de Genes , Humanos , Metabolômica , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Oxirredução , Fosforilação Oxidativa , Consumo de Oxigênio/genética , Caracteres Sexuais , Análise de Célula Única , Adulto JovemRESUMO
Multiple studies endorsed the positive effect of regular exercise on mental and physical health. However, the molecular mechanisms underlying training-induced fitness in combination with personal life-style remain largely unexplored. Circulating biomarkers such as microRNAs (miRNAs) offer themselves for studying systemic and cellular changes since they can be collected from the bloodstream in a low-invasive manner. In Homo sapiens miRNAs are known to regulate a substantial number of protein-coding genes in a post-transcriptional manner and hence are of great interest to understand differential gene expression profiles, offering a cost-effective mechanism to study molecular training adaption, and connecting the dots from genomics to observed phenotypes. Here, we investigated molecular expression patterns of 2549 miRNAs in whole-blood samples from 23 healthy and untrained adult participants of a cross-over study, consisting of eight weeks of endurance training, with several sessions per week, followed by 8 weeks of washout and another 8 weeks of running, using microarrays. Participants were randomly assigned to one of the two study groups, one of which administered carbohydrates before each session in the first training period, and switching the treatment group for the second training period. During running sessions clinical parameters as heartbeat frequency were recorded. This information was extended with four measurements of maximum oxygen uptake (VO 2 max) for each participant. We observed that multiple circulating miRNAs show expression changes after endurance training, leveraging the capability to separate the blood samples by training status. To this end, we demonstrate that most of the variance in miRNA expression can be explained by both common and known biological and technical factors. Our findings highlight six distinct clusters of miRNAs, each exhibiting an oscillating expression profile across the four study timepoints, that can effectively be utilized to predict phenotypic VO 2 max levels. In addition, we identified miR-532-5p as a candidate marker to determine personal alterations in physical training performance on a case-by-case analysis taking the influence of a carbohydrate-rich nutrition into account. In literature, miR-532-5p is known as a common down-regulated miRNA in diabetes and obesity, possibly providing a molecular link between cellular homeostasis, personal fitness levels, and health in aging. We conclude that circulating miRNA expression can be altered due to regular endurance training, independent of the carbohydrate (CHO) availability in the training timeframe. Further validation studies are required to confirm the role of exercise-affected miRNAs and the extraordinary function of miR-532-5p in modulating the metabolic response to a high availability of glucose.
Assuntos
Exercício Físico/fisiologia , MicroRNAs/genética , Consumo de Oxigênio/genética , Adulto , Biomarcadores/metabolismo , Metabolismo dos Carboidratos/genética , Carboidratos/genética , MicroRNA Circulante , Estudos Cross-Over , Feminino , Voluntários Saudáveis , Humanos , Masculino , MicroRNAs/análise , MicroRNAs/sangue , Músculo Esquelético/metabolismo , Oxigênio/metabolismo , Resistência Física/fisiologia , Corrida/fisiologiaRESUMO
Obesity is increasing in prevalence and has become a global public health problem. The main cause of obesity is a perturbation in energy homeostasis, whereby energy intake exceeds energy expenditure. Although mitochondrial dysfunction has been linked to the deregulation of energy homeostasis, the precise mechanism is poorly understood. Here, we identify mitochondrial p32 (also known as C1QBP) as an important regulator of lipid homeostasis that regulates both aerobic and anaerobic energy metabolism. We show that while whole-body deletion of the p32 results in an embryonic lethal phenotype, mice heterozygous for p32 are resistant to age- and high-fat diet-induced ailments, including obesity, hyperglycemia, and hepatosteatosis. Notably, p32 +/- mice are apparently healthy, demonstrate an increased lean-to-fat ratio, and show dramatically improved insulin sensitivity despite prolonged high-fat diet feeding. The p32 +/- mice show increased oxygen consumption and heat production, indicating that they expend more energy. Our analysis revealed that haploinsufficiency for p32 impairs glucose oxidation, which results in a compensatory increase in fatty acid oxidation and glycolysis. These metabolic alterations increase both aerobic and anaerobic energy expenditure. Collectively, our data show that p32 plays a critical role in energy homeostasis and represents a potential novel target for the development of anti-obesity drugs.
Assuntos
Metabolismo Energético/genética , Hiperglicemia/genética , Proteínas Mitocondriais/genética , Obesidade/genética , Animais , Dieta Hiperlipídica/efeitos adversos , Ingestão de Energia/genética , Glicólise/genética , Heterozigoto , Homeostase/genética , Hiperglicemia/etiologia , Hiperglicemia/metabolismo , Resistência à Insulina/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Mitocondriais/metabolismo , Obesidade/etiologia , Obesidade/metabolismo , Consumo de Oxigênio/genéticaRESUMO
The acquisition of antibiotic resistance has been associated with a possible nonspecific, metabolic burden that is reflected in decreased fitness among resistant bacteria. We have recently demonstrated that overexpression of the MexEF-OprN multidrug efflux pump does not produce a metabolic burden when measured by classical competitions tests but rather leads to a number of changes in the organism's physiology. One of these changes is the untimely activation of the nitrate respiratory chain under aerobic conditions. MexEF-OprN is a proton/substrate antiporter. Overexpression of this element should result in a constant influx of protons, which may lead to cytoplasmic acidification. Acidification was not observed in aerobiosis, a situation in which the MexEF-overproducing mutant increases oxygen consumption. This enhanced oxygen uptake serves to eliminate intracellular proton accumulation, preventing the cytoplasmic acidification that was observed exclusively under anaerobic conditions, a situation in which the fitness of the MexEF-OprN-overproducing mutant decreases. Finally, we determined that the early activation of the nitrate respiratory chain under aerobic conditions plays a role in preventing a deleterious effect associated with the overexpression of MexEF-OprN. Our results show that metabolic rewiring may assist in overcoming the potential fitness cost associated with the acquisition of antibiotic resistance. Furthermore, the capability to metabolically compensate for this effect is habitat dependent, as demonstrated by our results under anaerobic conditions. The development of drugs that prevent metabolic compensation of fitness costs may help to reduce the persistence and dissemination of antibiotic resistance.
Assuntos
Proteínas da Membrana Bacteriana Externa/genética , Farmacorresistência Bacteriana Múltipla/genética , Aptidão Genética/genética , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Anaerobiose , Transporte de Elétrons/genética , Aptidão Genética/fisiologia , Concentração de Íons de Hidrogênio , Mutação , Nitratos/metabolismo , Óxido Nítrico/metabolismo , Consumo de Oxigênio/genética , Pseudomonas aeruginosa/crescimento & desenvolvimento , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Divergent selection for heat loss was applied to lines of mice for 15 generations (G) in 3 replicates. Selection resumed at G42 and continued through G51 across all replicates. At the end of G51, differences in heat loss and feed intake per unit of BW were approximately 56 and 34%, respectively, between high heat loss (MH) and low heat loss (ML) lines, as a percentage of the control line (MC) mean. Rates of liver mitochondrial respiration states, degree of coupling, and mitochondrial efficiency were measured in G58 using a Clark-type oxygen electrode to investigate possible causes of underlying variation in maintenance requirements. Body composition, BW, liver weight, feed intake, and residual feed intake (RFI) were also measured or calculated. Results reported here represent data from 197 mature male mice from all replicates. There were no differences in BW (P = 0.91) between the selection lines. Selection had an effect on lean percentage (P = 0.02), with MH mice being leaner. Fat percentage differences between the selection lines tended toward significance (P = 0.13). Livers of MH mice were approximately 13% larger than livers of ML mice (P = 0.01). An effect of selection was observed (P < 0.01) in feed intake per unit BW, with MH mice consuming 29% more feed than ML mice in G58. Differences in state 2 and state 4 respiration rates were significant (P = 0.01), whereas state 3 rates approached significance (P = 0.06). Mitochondria of MH mice respired at a greater rate than mitochondria of ML mice in all states of respiration; ML mice had respiratory control ratios that were, on average, 8% greater than MH mice (P = 0.14). Although this difference only tended toward significance, we suspect a greater degree of coupling of mitochondrial processes exists in ML animals. Mice selected for reduced heat loss had ADP:oxygen ratios that were approximately 20% greater than MH mice (P = 0.03). Therefore, greater mitochondrial efficiency was expressed in the ML animals. Within a line-replicate, there was no correlation between ADP:O and feed intake per unit BW (P = 0.71). In addition, no correlation of ADP:O and RFI existed (P = 0.92). Although the selection lines differed in mitochondrial traits, including overall mitochondrial efficiency (ADP:oxygen), these differences were not a significant underlying cause of variation in feed intake per unit BW or in RFI estimates.
Assuntos
Regulação da Temperatura Corporal/fisiologia , Fígado/fisiologia , Camundongos/fisiologia , Mitocôndrias Hepáticas/fisiologia , Seleção Genética/fisiologia , Animais , Regulação da Temperatura Corporal/genética , Peso Corporal/genética , Peso Corporal/fisiologia , Ingestão de Alimentos/genética , Ingestão de Alimentos/fisiologia , Humanos , Masculino , Camundongos/genética , Consumo de Oxigênio/genética , Consumo de Oxigênio/fisiologia , Análise de Regressão , Seleção Genética/genéticaRESUMO
The FTO gene has significant polymorphic variation associated with obesity, but its function is unknown. We screened a population of 150 whites (103F/47M) resident in NE Scotland, United Kingdom, for variants of the FTO gene and linked these to phenotypic variation in their energy expenditure (basal metabolic rate (BMR) and maximal oxygen consumption VO(2)max) and energy intake. There was no significant association between the FTO genotype and BMR or VO(2)max. The FTO genotype was significantly associated (P = 0.024) with variation in energy intake, with average daily intake being 9.0 MJ for the wild-type TT genotype and 10.2 and 9.5 MJ for the "at risk" AT and AA genotypes, respectively. Adjusting intake for BMR did not remove the significance (P = 0.043). FTO genotype probably affects obesity via effects on food intake rather than energy expenditure.
Assuntos
Ingestão de Energia/genética , Metabolismo Energético/genética , Polimorfismo de Nucleotídeo Único/genética , Proteínas/genética , Adulto , Dioxigenase FTO Dependente de alfa-Cetoglutarato , Metabolismo Basal/genética , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/epidemiologia , Obesidade/genética , Consumo de Oxigênio/genética , Fenótipo , Fatores de Risco , EscóciaRESUMO
BACKGROUND: We undertook this study to investigate the association of a genetic polymorphism of the insulin-like growth factor, IGF-I(189), on body composition, exercise performance and exercise economy, after controlling for the independent effect of race as assessed by African genetic admixture (AFADM). METHODS: A total of 114 premenopausal sedentary women were genotyped for IGF-I189, obtaining measures of fat mass, lean body mass, VO2 during cycling and stairclimbing, time on treadmill and leg strength. A quantitative value for AFADM was derived from genotypic information of approximately 40 ancestry informative markers and used as covariate in statistical models. RESULTS: After adjusting for AFADM, IGF-I189 was negatively associated with lean body mass (p = 0.029) and lean leg mass (p = 0.050). Leg strength was not associated with the presence/absence of IGF-I189 (p = 0.380), but carriers of the allele demonstrated a longer time on the treadmill (p = 0.015) after adjusting for AFADM. There was also a negative relationship between oxygen uptake during cycling and presence of the IGF-I189 independent of AFADM (p = 0.010). CONCLUSIONS: Independent of AFADM, individuals with IGF-I189 are more likely to have low leg lean mass and to perform better in activities requiring exercise economy and endurance performance.
Assuntos
Composição Corporal/genética , Fator de Crescimento Insulin-Like I/genética , Aptidão Física , Polimorfismo Genético , Adulto , Negro ou Afro-Americano/genética , Exercício Físico , Feminino , Humanos , Perna (Membro)/anatomia & histologia , Pessoa de Meia-Idade , Tamanho do Órgão , Consumo de Oxigênio/genética , Pré-Menopausa , População Branca/genéticaRESUMO
Despite their young age, limited training history, and lack of running tradition compared with other East African endurance athletes (e.g., Kenyans and Ethiopians), male endurance runners from Eritrea have recently attained important running successes. The purposes of our study were (i) to document the main physical and physiological characteristics of elite black Eritrean distance runners (n = 7; age: 22 +/- 3 years) and (ii) to compare them with those of their elite white Spanish counterparts. For this second purpose we selected a control group of elite Spanish runners (n = 9; 24 +/- 2 years), owing to the traditionally high success of Spanish athletes in long-distance running compared with other white runners, especially in cross-country competitions. The subjects' main anthropometric characteristics were determined, together with their maximum oxygen uptake (VO2 max) and VO2 (mL.kg(-1).min(-1)), blood lactate, and ammonia concentrations while running at 17, 19, or 21 km.h(-1). The body mass index (18.9 +/- 1.5 kg.m(-2)) and maximal calf circumference (30.9 +/- 1.5 cm) was lower in Eritreans than in Spaniards (20.5 +/- 1.7 kg.m(-2) and 33.9 +/- 2.0 cm, respectively) (p < 0.05 and p < 0.01, respectively) and their lower leg (shank) length was longer (44.1 +/- 3.0 cm vs. 40.6 +/- 2.7 cm, respectively) (p < 0.05). VO2 max did not differ significantly between Eritreans and Spaniards (73.8 +/- 5.6 mL.kg(-1).min(-1) vs. 77.8 +/- 5.7 mL.kg(-1).min(-1), respectively), whereas the VO2 cost of running was lower (p < 0.01) in the former (e.g., 65.9 +/- 6.8 mL.kg(-1).min(-1) vs. 74.8 +/- 5.0 mL.kg(-1).min(-1) when running at 21 km.h(-1)). Our data suggest that the excellent running economy of Eritreans is associated, at least partly, with anthropometric variables. Comparison of their submaximal running cost with other published data suggests that superior running economy, rather than enhanced aerobic capacity, may be the common denominator in the success of black endurance runners of East African origin.
Assuntos
Corrida/fisiologia , Adulto , Amônia/sangue , Antropometria , População Negra , Índice de Massa Corporal , Eritreia , Genótipo , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio/genética , Resistência Física/genética , EspanhaRESUMO
OBJECTIVE: To investigate the association between muscle-specific creatine kinase (CKMM) gene polymorphism and the effects of endurance training on running economy. METHODS: 102 biologically unrelated male volunteers from northern China performed a 5000-m running programme, with an intensity of 95-105% ventilatory threshold. The protocol was undertaken three times per week and lasted for 18 weeks. Running economy indexes were determined by making the participants run on a treadmill before and after the protocol, and the A/G polymorphism in the 3' untranslated region of CKMM was detected by polymerase chain reaction-restricted fragment length polymorphism (NcoI restriction enzyme). RESULTS: Three expected genotypes for CKMM-NcoI (AA, AG and GG) were observed in the participants. After training, all running economy indexes declined markedly. Change in steady-state consumption of oxygen, change in steady-state consumption of oxygen by mean body weight, change in steady-state consumption of oxygen by mean lean body weight and change in ventilatory volume in AG groups were larger than those in AA and GG groups. CONCLUSIONS: The findings indicate that the CKMM gene polymorphism may contribute to individual running economy responses to endurance training.
Assuntos
Creatina Quinase/genética , Músculo Esquelético/enzimologia , Polimorfismo Genético/fisiologia , Corrida/fisiologia , Adolescente , Adulto , Peso Corporal/fisiologia , Distribuição de Qui-Quadrado , China , Creatina Quinase/fisiologia , Humanos , Masculino , Músculo Esquelético/fisiologia , Consumo de Oxigênio/genética , Consumo de Oxigênio/fisiologia , Educação Física e Treinamento/métodos , Resistência Física/genética , Resistência Física/fisiologia , Polimorfismo Genético/genéticaRESUMO
Disruption of the RIIbeta regulatory subunit of protein kinase A (PKA) results in mice with a lean phenotype, nocturnal hyperactivity, and increased resting metabolic rate. In this report, we have examined whether deletion of RIIbeta would lead to increased metabolism and rescue the obese phenotype of the leptin-deficient ob/ob (ob) mouse. Body weight gain and food consumption were decreased, whereas basal oxygen consumption and nocturnal locomotor activity were increased in the double mutant animals compared with ob mice. The ob mice are unable to maintain body temperature when placed in a cold environment due to a loss of brown adipose tissue activation, and this cold sensitivity was partially rescued by concomitant disruption of RIIbeta. These findings indicate that PKA modifies the phenotype of the leptin-deficient mouse, leading to increases in both thermogenesis and energy expenditure.
Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Obesidade/enzimologia , Redução de Peso , Tecido Adiposo Marrom/citologia , Tecido Adiposo Marrom/metabolismo , Animais , Regulação da Temperatura Corporal/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Subunidade RIIbeta da Proteína Quinase Dependente de AMP Cíclico , Proteínas Quinases Dependentes de AMP Cíclico/genética , Metabolismo Energético , Deleção de Genes , Expressão Gênica , Canais Iônicos , Leptina/deficiência , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Obesos , Proteínas Mitocondriais , Atividade Motora/genética , Obesidade/genética , Consumo de Oxigênio/genética , RNA/metabolismo , Proteína Desacopladora 1 , Regulação para CimaRESUMO
UNLABELLED: Sedentary lifestyles are increasingly common and result in low cardiorespiratory fitness ([OV0312]O2max), a well-established predictor of early mortality and coronary heart disease (CHD). Adaptation in [OV0312]O2max after exercise training varies considerably between people. Because there are hereditary components to fitness, it is likely that genetic factors explain some of this variability. PPARGC1 (PGC-1alpha) coactivates genes involved in energy transduction and mitochondrial biogenesis. Transgenic mouse data demonstrate that overexpression of PGC-1alpha mRNA increases endurance capacity by transformation of nonoxidative to oxidative skeletal muscle tissue. Other murine studies demonstrate that exercise increases PGC-1alpha mRNA expression. PURPOSE: To explore whether a candidate polymorphism in the PGC-1alpha gene modifies the association between physical activity energy expenditure (PAEE) and predicted [OV0312]O2max ([OV0312]O2max.pred). METHOD: We examined whether the Gly482Ser polymorphism of PGC-1alpha modified the relationship between objectively measured PAEE and [OV0312]O2max.pred in a population-based sample of 599 healthy middle-aged people. PAEE was assessed using individual calibration with 4 d of heart rate monitoring. [OV0312]O2max.pred was measured during a submaximal exercise stress test on a bicycle ergometer. RESULTS: Homozygosity at the Ser482 allele was found in 12.7% of the cohort, whereas 38.9% and 48.4% carried the Gly482Gly and Gly482Ser genotypes, respectively. The association between PAEE and [OV0312]O2max.pred (mL x kg(-1) x min(-1)) was strongest in people homozygous for the Ser482 allele (beta = 12.03; P < 0.00001) compared with carriers of the Gly allele (beta = 5.61; P < 0.00001). In a recessive model for the Ser482 allele, the interaction between PAEE and genotype on [OV0312]O2max.pred (L x min(-1)) was highly significant (P = 0.009). CONCLUSION: Our results indicate that Ser482 homozygotes may be most capable of improving cardiorespiratory fitness when physically active, and that Gly482Ser may explain some of the between-person variance previously reported in cardiorespiratory adaptation after exercise training.