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BACKGROUND: Circulating osteoprogenitors (COP) are a population of cells in the peripheral circulation that possess functional and phenotypical characteristics of multipotent stromal cells (MSCs). This population has a solid potential to become an abundant, accessible, and replenishable source of MSCs with multiple potential clinical applications. However, a comprehensive functional characterization of COP cells is still required to test and fully develop their use in clinical settings. METHODS: This study characterized COP cells by comparing them to bone marrow-derived MSCs (BM-MSCs) and adipose-derived MSCs (ASCs) through detailed transcriptomic and proteomic analyses. RESULTS: We demonstrate that COP cells have a distinct gene and protein expression pattern with a significantly stronger immune footprint, likely owing to their hematopoietic lineage. In addition, regarding progenitor cell differentiation and proliferation pathways, COP cells have a similar expression pattern to BM-MSCs and ASCs. CONCLUSION: COP cells are a unique but functionally similar population to BM-MSCs and ASCs, sharing their proliferation and differentiation capacity, thus presenting an accessible source of MSCs with strong potential for translational regenerative medicine strategies.
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Tecido Adiposo , Células-Tronco Mesenquimais , Humanos , Tecido Adiposo/metabolismo , Proteômica , Células da Medula Óssea , Diferenciação Celular/fisiologia , Células-Tronco Mesenquimais/metabolismo , Células Cultivadas , Proliferação de CélulasRESUMO
Exercise is a major beneficial contributor to muscle metabolism, and health benefits acquired by exercise are a result of molecular shifts occurring across multiple molecular layers (i.e., epigenome, transcriptome, and proteome). Identifying robust, across-molecular level targets associated with exercise response, at both group and individual levels, is paramount to develop health guidelines and targeted health interventions. Sixteen, apparently healthy, moderately trained (VO2 max = 51.0 ± 10.6 mL min-1 kg-1 ) males (age range = 18-45 years) from the Gene SMART (Skeletal Muscle Adaptive Responses to Training) study completed a longitudinal study composed of 12-week high-intensity interval training (HIIT) intervention. Vastus lateralis muscle biopsies were collected at baseline and after 4, 8, and 12 weeks of HIIT. DNA methylation (~850 CpG sites) and proteomic (~3000 proteins) analyses were conducted at all time points. Mixed models were applied to estimate group and individual changes, and methylome and proteome integration was conducted using a holistic multilevel approach with the mixOmics package. A total of 461 proteins significantly changed over time (at 4, 8, and 12 weeks), whilst methylome overall shifted with training only one differentially methylated position (DMP) was significant (adj.p-value < .05). K-means analysis revealed cumulative protein changes by clusters of proteins that presented similar changes over time. Individual responses to training were observed in 101 proteins. Seven proteins had large effect-sizes >0.5, among them are two novel exercise-related proteins, LYRM7 and EPN1. Integration analysis showed bidirectional relationships between the methylome and proteome. We showed a significant influence of HIIT on the epigenome and more so on the proteome in human muscle, and uncovered groups of proteins clustering according to similar patterns across the exercise intervention. Individual responses to exercise were observed in the proteome with novel mitochondrial and metabolic proteins consistently changed across individuals. Future work is required to elucidate the role of these proteins in response to exercise.
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Treinamento Intervalado de Alta Intensidade , Proteoma , Masculino , Humanos , Lactente , Epigenoma , Estudos Longitudinais , Proteômica , Músculo Esquelético , Chaperonas Moleculares , Proteínas MitocondriaisRESUMO
BACKGROUND: Sex differences in microRNA (miRNA) expression profiles have been found across multiple tissues. Skeletal muscle is one of the most sex-biased tissues of the body. MiRNAs are necessary for development and have regulatory roles in determining skeletal muscle phenotype and have important roles in the response to exercise in muscle. Yet there is limited research into the role and regulation of miRNAs in the skeletal muscle at baseline and in response to exercise, a well-known modulator of miRNA expression. The aim of this study was to investigate the effect of sex on miRNA expression in the skeletal muscle at baseline and after an acute bout of high-intensity interval exercise. A total of 758 miRNAs were measured using Taqman®miRNA arrays in the skeletal muscle of 42 healthy participants from the Gene SMART study (23 males and 19 females of comparable fitness levels and aged 18-45 years), of which 308 were detected. MiRNAs that differed by sex at baseline and whose change in expression following high-intensity interval exercise differed between the sexes were identified using mixed linear models adjusted for BMI and Wpeak. We performed in silico analyses to identify the putative gene targets of the exercise-induced, sex-specific miRNAs and overrepresentation analyses to identify enriched biological pathways. We performed functional assays by overexpressing two sex-biased miRNAs in human primary muscle cells derived from male and female donors to understand their downstream effects on the transcriptome. RESULTS: At baseline, 148 miRNAs were differentially expressed in the skeletal muscle between the sexes. Interaction analysis identified 111 miRNAs whose response to an acute bout of high-intensity interval exercise differed between the sexes. Sex-biased miRNA gene targets were enriched for muscle-related processes including proliferation and differentiation of muscle cells and numerous metabolic pathways, suggesting that miRNAs participate in programming sex differences in skeletal muscle function. Overexpression of sex-biased miRNA-30a and miRNA-30c resulted in profound changes in gene expression profiles that were specific to the sex of the cell donor in human primary skeletal muscle cells. CONCLUSIONS: We uncovered sex differences in the expression levels of muscle miRNAs at baseline and in response to acute high-intensity interval exercise. These miRNAs target regulatory pathways essential to skeletal muscle development and metabolism. Our findings highlight that miRNAs play an important role in programming sex differences in the skeletal muscle phenotype.
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MicroRNAs , Humanos , Feminino , Masculino , MicroRNAs/genética , MicroRNAs/metabolismo , Transcriptoma , Músculo Esquelético/metabolismo , Diferenciação Celular , Caracteres SexuaisRESUMO
Sex differences in exercise physiology, such as substrate metabolism and skeletal muscle fatigability, stem from inherent biological factors, including endogenous hormones and genetics. Studies investigating exercise physiology frequently include only males or do not take sex differences into consideration. Although there is still an underrepresentation of female participants in exercise research, existing studies have identified sex differences in physiological and molecular responses to exercise training. The observed sex differences in exercise physiology are underpinned by the sex chromosome complement, sex hormones and, on a molecular level, the epigenome and transcriptome. Future research in the field should aim to include both sexes, control for menstrual cycle factors, conduct large-scale and ethnically diverse studies, conduct meta-analyses to consolidate findings from various studies, leverage unique cohorts (such as post-menopausal, transgender, and those with sex chromosome abnormalities), as well as integrate tissue and cell-specific -omics data. This knowledge is essential for developing deeper insight into sex-specific physiological responses to exercise training, thus directing future exercise physiology studies and practical application.
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Exercício Físico , Músculo Esquelético , Caracteres Sexuais , Feminino , Humanos , Masculino , Exercício Físico/fisiologia , Hormônios Esteroides Gonadais/fisiologia , Músculo Esquelético/fisiologiaRESUMO
Mitochondrial respiration using the oxygraph-2k respirometer (Oroboros) is widely used to estimate mitochondrial capacity in human skeletal muscle. Here, we measured mitochondrial respiration variability, in a relatively large sample, and for the first time, using statistical simulations, we provide the sample size required to detect meaningful respiration changes following lifestyle intervention. Muscle biopsies were taken from healthy, young men from the Gene SMART cohort, at multiple time points. We utilized samples for each measurement with two technical repeats using two respirometer chambers (n = 160 pairs of same muscle after removal of low-quality samples). We measured the Technical Error of measurement (TEM ) and the coefficient of variation (CV) for each mitochondrial complex. There was a high correlation between measurements from the two chambers (R > 0.7 P < .001) for all complexes, but the TEM was large (7.9-27 pmol s-1 mg-1 ; complex dependent), and the CV was >15% for all complexes. We performed statistical simulations of a range of effect sizes at 80% power and found that 75 participants (with duplicate measurements) are required to detect a 6% change in mitochondrial respiration after an intervention, while for interventions with 11% effect size, ~24 participants are sufficient. The high variability in respiration suggests that the typical sample sizes in exercise studies may not be sufficient to capture exercise-induced changes.
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Exercício Físico/fisiologia , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Consumo de Oxigênio/fisiologia , Oxigênio/metabolismo , Adulto , Feminino , Humanos , MasculinoRESUMO
BACKGROUND: Low cardiorespiratory fitness (VÌO2peak) is highly associated with chronic disease and mortality from all causes. Whilst exercise training is recommended in health guidelines to improve VÌO2peak, there is considerable inter-individual variability in the VÌO2peak response to the same dose of exercise. Understanding how genetic factors contribute to VÌO2peak training response may improve personalisation of exercise programs. The aim of this study was to identify genetic variants that are associated with the magnitude of VÌO2peak response following exercise training. METHODS: Participant change in objectively measured VÌO2peak from 18 different interventions was obtained from a multi-centre study (Predict-HIIT). A genome-wide association study was completed (n = 507), and a polygenic predictor score (PPS) was developed using alleles from single nucleotide polymorphisms (SNPs) significantly associated (P < 1 × 10-5) with the magnitude of VÌO2peak response. Findings were tested in an independent validation study (n = 39) and compared to previous research. RESULTS: No variants at the genome-wide significance level were found after adjusting for key covariates (baseline VÌO2peak, individual study, principal components which were significantly associated with the trait). A Quantile-Quantile plot indicates there was minor inflation in the study. Twelve novel loci showed a trend of association with VÌO2peak response that reached suggestive significance (P < 1 × 10-5). The strongest association was found near the membrane associated guanylate kinase, WW and PDZ domain containing 2 (MAGI2) gene (rs6959961, P = 2.61 × 10-7). A PPS created from the 12 lead SNPs was unable to predict VÌO2peak response in a tenfold cross validation, or in an independent (n = 39) validation study (P > 0.1). Significant correlations were found for beta coefficients of variants in the Predict-HIIT (P < 1 × 10-4) and the validation study (P < × 10-6), indicating that general effects of the loci exist, and that with a higher statistical power, more significant genetic associations may become apparent. CONCLUSIONS: Ongoing research and validation of current and previous findings is needed to determine if genetics does play a large role in VÌO2peak response variance, and whether genomic predictors for VÌO2peak response trainability can inform evidence-based clinical practice. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR), Trial Id: ACTRN12618000501246, Date Registered: 06/04/2018, http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374601&isReview=true .
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Aptidão Cardiorrespiratória/fisiologia , Exercício Físico/fisiologia , Variação Genética , Estudo de Associação Genômica Ampla , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The individual response to exercise training is of great interest with methods that have been proposed to measure this response reviewed in this paper. However, individual training response estimates may be biased by various sources of variability present in exercise studies, and in particular by within-subject variability. We propose the use of protocols that can separate trainability from within-subject variability.
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Exercício Físico/fisiologia , Condicionamento Físico Humano/métodos , Projetos de Pesquisa , HumanosRESUMO
BACKGROUND: Studies investigating associations between ACTN3 R577X and ACE I/D genotypes and endurance athletic status have been limited by small sample sizes from mixed sport disciplines and lack quantitative measures of performance. AIM: To examine the association between ACTN3 R577X and ACE I/D genotypes and best personal running times in a large homogeneous cohort of endurance runners. METHODS: We collected a total of 1064 personal best 1500, 3000, 5000 m and marathon running times of 698 male and female Caucasian endurance athletes from six countries (Australia, Greece, Italy, Poland, Russia and UK). Athletes were genotyped for ACTN3 R577X and ACE ID variants. RESULTS: There was no association between ACTN3 R577X or ACE I/D genotype and running performance at any distance in men or women. Mean (SD) marathon times (in s) were for men: ACTN3 RR 9149 (593), RX 9221 (582), XX 9129 (582) p = 0.94; ACE DD 9182 (665), ID 9214 (549), II 9155 (492) p = 0.85; for women: ACTN3 RR 10796 (818), RX 10667 (695), XX 10675 (553) p = 0.36; ACE DD 10604 (561), ID 10766 (740), II 10771 (708) p = 0.21. Furthermore, there were no associations between these variants and running time for any distance in a sub-analysis of athletes with personal records within 20% of world records. CONCLUSIONS: Thus, consistent with most case-control studies, this multi-cohort quantitative analysis demonstrates it is unlikely that ACTN3 XX genotype provides an advantage in competitive endurance running performance. For ACE II genotype, some prior studies show an association but others do not. Our data indicate it is also unlikely that ACE II genotype provides an advantage in endurance running.
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Actinina/genética , Atletas , Peptidil Dipeptidase A/genética , Resistência Física/genética , Polimorfismo Genético , Corrida/fisiologia , Feminino , Genótipo , Humanos , Masculino , População Branca/genéticaRESUMO
The focus on maintaining health and vitality (e.g., good healthspan) in later life has become increasingly important as the world's population is getting older. In the last decade, advances in aging research have identified biomarkers like DNA methylation (DNAm) and gene expression, offering insights into both chronological and biological aging. This understanding opens up possibilities for interventions that can slow down molecular aspects of the aging process. Exploring the impact of exercise on these biomarkers in human skeletal muscle (a critical tissue for metabolism, thermogenesis and movement) reveals its potential to foster healthier aging.
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Envelhecimento , Biomarcadores , Metilação de DNA , Exercício Físico , Músculo Esquelético , Humanos , Músculo Esquelético/metabolismo , Exercício Físico/fisiologia , Envelhecimento/fisiologia , Envelhecimento/metabolismo , Biomarcadores/metabolismoRESUMO
Exercise training prevents age-related decline in muscle function. Targeting epigenetic aging is a promising actionable mechanism and late-life exercise mitigates epigenetic aging in rodent muscle. Whether exercise training can decelerate, or reverse epigenetic aging in humans is unknown. Here, we performed a powerful meta-analysis of the methylome and transcriptome of an unprecedented number of human skeletal muscle samples (n = 3176). We show that: (1) individuals with higher baseline aerobic fitness have younger epigenetic and transcriptomic profiles, (2) exercise training leads to significant shifts of epigenetic and transcriptomic patterns toward a younger profile, and (3) muscle disuse "ages" the transcriptome. Higher fitness levels were associated with attenuated differential methylation and transcription during aging. Furthermore, both epigenetic and transcriptomic profiles shifted toward a younger state after exercise training interventions, while the transcriptome shifted toward an older state after forced muscle disuse. We demonstrate that exercise training targets many of the age-related transcripts and DNA methylation loci to maintain younger methylome and transcriptome profiles, specifically in genes related to muscle structure, metabolism, and mitochondrial function. Our comprehensive analysis will inform future studies aiming to identify the best combination of therapeutics and exercise regimes to optimize longevity.
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Epigenoma , Transcriptoma , Humanos , Transcriptoma/genética , Epigenoma/genética , Músculo Esquelético/metabolismo , Exercício Físico/fisiologia , Perfilação da Expressão GênicaRESUMO
Multiple statistical methods have been proposed to estimate individual responses to exercise training; yet, the evaluation of these methods is lacking. We compared five of these methods including the following: the use of a control group, a control period, repeated testing during an intervention, a reliability trial and a repeated intervention. Apparently healthy males from the Gene SMART study completed a 4-week control period, 4 weeks of High-Intensity Interval Training (HIIT), >1 year of washout, and then subsequently repeated the same 4 weeks of HIIT, followed by an additional 8 weeks of HIIT. Aerobic fitness measurements were measured in duplicates at each time point. We found that the control group and control period were not intended to measure the degree to which individuals responded to training, but rather estimated whether individual responses to training can be detected with the current exercise protocol. After a repeated intervention, individual responses to 4 weeks of HIIT were not consistent, whereas repeated testing during the 12-week-long intervention was able to capture individual responses to HIIT. The reliability trial should not be used to study individual responses, rather should be used to classify participants as responders with a certain level of confidence. 12 weeks of HIIT with repeated testing during the intervention is sufficient and cost-effective to measure individual responses to exercise training since it allows for a confident estimate of an individual's true response. Our study has significant implications for how to improve the design of exercise studies to accurately estimate individual responses to exercise training interventions.HighlightsWhat are the findings? We implemented five statistical methods in a single study to estimate the magnitude of within-subject variability and quantify responses to exercise training at the individual level.The various proposed methods used to estimate individual responses to training provide different types of information and rely on different assumptions that are difficult to test.Within-subject variability is often large in magnitude, and as such, should be systematically evaluated and carefully considered in future studies to successfully estimate individual responses to training.How might it impact on clinical practice in the future?Within-subject variability in response to exercise training is a key factor that must be considered in order to obtain a reproducible measurement of individual responses to exercise training. This is akin to ensuring data are reproducible for each subject.Our findings provide guidelines for future exercise training studies to ensure results are reproducible within participants and to minimise wasting precious research resources.By implementing five suggested methods to estimate individual responses to training, we highlight their feasibility, strengths, weaknesses and costs, for researchers to make the best decision on how to accurately measure individual responses to exercise training.
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Exercício Físico , Treinamento Intervalado de Alta Intensidade , Masculino , Humanos , Reprodutibilidade dos Testes , Exercício Físico/fisiologia , Nível de SaúdeRESUMO
Many transgender (trans) individuals utilize gender-affirming hormone therapy (GAHT) to promote changes in secondary sex characteristics to affirm their gender. Participation rates of trans people in sport are exceedingly low, yet given high rates of depression and increased cardiovascular risk, the potential benefits of sports participation are great. In this review, we provide an overview of the evidence surrounding the effects of GAHT on multiple performance-related phenotypes, as well as current limitations. Whilst data is clear that there are differences between males and females, there is a lack of quality evidence assessing the impact of GAHT on athletic performance. Twelve months of GAHT leads to testosterone concentrations that align with reference ranges of the affirmed gender. Feminizing GAHT in trans women increases fat mass and decreases lean mass, with opposite effects observed in trans men with masculinizing GAHT. In trans men, an increase in muscle strength and athletic performance is observed. In trans women, muscle strength is shown to decrease or not change following 12 months of GAHT. Haemoglobin, a measure of oxygen transport, changes to that of the affirmed gender within 6 months of GAHT, with very limited data to suggest possible reductions in maximal oxygen uptake as a result of feminizing GAHT. Current limitations of this field include a lack of long-term studies, adequate group comparisons and adjustment for confounding factors (e.g. height and lean body mass), and small sample sizes. There also remains limited data on endurance, cardiac or respiratory function, with further longitudinal studies on GAHT needed to address current limitations and provide more robust data to inform inclusive and fair sporting programmes, policies and guidelines.
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BACKGROUND: Exercise training elicits changes in muscle physiology, epigenomics, transcriptomics, and proteomics, with males and females exhibiting differing physiological responses to exercise training. However, the molecular mechanisms contributing to the differing adaptations between the sexes are poorly understood. METHODS: We performed a meta-analysis for sex differences in skeletal muscle DNA methylation following an endurance training intervention (Gene SMART cohort and E-MTAB-11282 cohort). We investigated for sex differences in the skeletal muscle proteome following an endurance training intervention (Gene SMART cohort). Lastly, we investigated whether the methylome and proteome are associated with baseline cardiorespiratory fitness (maximal oxygen consumption; VO2max) in a sex-specific manner. RESULTS: Here, we investigated for the first time, DNA methylome and proteome sex differences in response to exercise training in human skeletal muscle (n = 78; 50 males, 28 females). We identified 92 DNA methylation sites (CpGs) associated with exercise training; however, no CpGs changed in a sex-dependent manner. In contrast, we identified 189 proteins that are differentially expressed between the sexes following training, with 82 proteins differentially expressed between the sexes at baseline. Proteins showing the most robust sex-specific response to exercise include SIRT3, MRPL41, and MBP. Irrespective of sex, cardiorespiratory fitness was associated with robust methylome changes (19,257 CpGs) and no proteomic changes. We did not observe sex differences in the association between cardiorespiratory fitness and the DNA methylome. Integrative multi-omic analysis identified sex-specific mitochondrial metabolism pathways associated with exercise responses. Lastly, exercise training and cardiorespiratory fitness shifted the DNA methylomes to be more similar between the sexes. CONCLUSIONS: We identified sex differences in protein expression changes, but not DNA methylation changes, following an endurance exercise training intervention; whereas we identified no sex differences in the DNA methylome or proteome response to lifelong training. Given the delicate interaction between sex and training as well as the limitations of the current study, more studies are required to elucidate whether there is a sex-specific training effect on the DNA methylome. We found that genes involved in mitochondrial metabolism pathways are differentially modulated between the sexes following endurance exercise training. These results shed light on sex differences in molecular adaptations to exercise training in skeletal muscle.
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Proteínas Musculares , Proteoma , Feminino , Masculino , Humanos , Músculo Esquelético , Exercício Físico , Metilação de DNARESUMO
Previous small-scale studies have shown an association between the COL5A1 gene and anterior cruciate ligament (ACL) injury risk. In this larger study, the genotype and allele frequency distributions of the COL5A1 rs12722 C/T and rs10628678 AGGG/deletion (AGGG/-) indel variants were compared between participants: (i) with ACL injury in independent and combined cohorts from South-Africa (SA) and Australia (AUS) vs controls (CON), and (ii) with any ligament (ALL) or only ACL injury in a Japanese (JPN) cohort vs CON. Samples were collected from SA (235 cases; 232 controls), AUS (362 cases; 80 controls) and JPN (500 cases; 1,403 controls). Genomic DNA was extracted and genotyped. Distributions were compared, and inferred haplotype analyses performed. No independent associations were noted for rs12722 or rs10628678 when the combined SA + AUS cohort was analysed. However, the C-deletion (rs12722-rs10628678) inferred haplotype was under-represented (p = 0.040, OR = 0.15, CI = 0.04-0.56), while the T-deletion inferred haplotype was over-represented in the female SA + AUS ACL participants versus controls (p < 0.001, OR = 4.74, CI = 1.66-13.55). Additionally, the rs12722 C/C genotype was under-represented in JPN CON vs ACL (p = 0.039, OR = 0.52, 0.27-1.00), while the rs10628678 -/- genotype was associated with increased risk of any ligament injuries (p = 0.035, OR = 1.31, CI = 1.02-1.68) in the JPN cohort. Collectively, these results highlight that a region within the COL5A1 3'-UTR is associated with ligament injury risk. This must be evaluated in larger cohorts and its functional relevance to the structure and capacity of ligaments and joint biomechanics be explored.Highlights The COL5A1 T-deletion inferred haplotype (rs12722-rs10628678) was associated with an increased risk of ACL rupture in the combined SA and AUS female participants.The COL5A1 C-deletion inferred haplotype (rs12722-rs10628678) was associated with a decreased risk of ACL rupture in the combined SA and AUS female participants.The COL5A1 rs12722 C/C and rs10628678 -/- genotypes were associated with increased risk of ACL rupture and of ligament injuries in JPN, respectively.A region within the COL5A1 3'-UTR is associated with risk of ligament injury, including ACL rupture, and therefore the functional significance of this region on ligament capacity and joint biomechanics requires further exploration.
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Lesões do Ligamento Cruzado Anterior , Humanos , Feminino , África do Sul , Japão , Colágeno Tipo V/genética , Genótipo , Estudos de Casos e ControlesRESUMO
CONTEXT: Osteoglycin (OGN) is a proteoglycan released from bone and muscle which has been associated with markers of metabolic health. However, it is not clear whether the levels of circulating OGN change throughout the adult lifespan or if they are associated with clinical metabolic markers or fitness. OBJECTIVE: We aimed to identify the levels of circulating OGN across the lifespan and to further explore the relationship between OGN and aerobic capacity as well as OGN's association with glucose and HOMA-IR. METHODS: 107 individuals (46 males and 61 females) aged 21-87 years were included in the study. Serum OGN levels, aerobic capacity (VO2peak), glucose, and homeostatic model assessment for insulin resistance (HOMA-IR) were assessed. T-tests were used to compare participant characteristics between sexes. Regression analyses were performed to assess the relationship between OGN and age, and OGN and fitness and metabolic markers. RESULTS: OGN displayed a nonlinear, weak "U-shaped" relationship with age across both sexes. Men had higher levels of OGN than women across the lifespan (ß = 0.23, P = .03). Age and sex explained 16% of the variance in OGN (adjusted R2 = 0.16; P < .001). Higher OGN was associated with higher VO2peak (ß = 0.02, P = .001); however, those aged <50 showed a stronger positive relationship than those aged >50. A higher OGN level was associated with a higher circulating glucose level (ß = 0.17, P < .01). No association was observed between OGN and HOMA-IR. CONCLUSION: OGN was characterized by a U-shaped curve across the lifespan which was similar between sexes. Those with a higher aerobic capacity or higher glucose concentration had higher OGN levels. Our data suggest an association between OGN and aerobic fitness and glucose regulation. Future studies should focus on exploring the potential of OGN as a biomarker for chronic disease.
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Resistência à Insulina , Longevidade , Biomarcadores , Osso e Ossos , Feminino , Glucose , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , MasculinoRESUMO
INTRODUCTION: Gender affirming hormone therapy (GAHT) is increasingly used by transgender individuals and leads to shifts in sex hormone levels. Skeletal muscle is highly responsive to hormone activity, with limited data on the effects of GAHT on different human tissues. Here, we present the protocol for the GAME study (the effects of Gender Affirming hormone therapy on skeletal Muscle training and Epigenetics), which aims to uncover the effects of GAHT on skeletal muscle 'omic' profiles (methylomics, transcriptomics, proteomics, metabolomics) and markers of skeletal muscle health and fitness. METHODS AND ANALYSIS: This study is a prospective age-matched cohort study in transgender adults commencing GAHT (n=80) and age-matched individuals not commencing GAHT (n=80), conducted at Austin Health and Victoria University in Victoria, Australia. Assessments will take place prior to beginning GAHT and 6 and 12 months into therapies in adults commencing GAHT. Age-matched individuals will be assessed at the same time points. Assessments will be divided over three examination days, involving (1) aerobic fitness tests, (2) muscle strength assessments and (3) collection of blood and muscle samples, as well as body composition measurements. Standardised diets, fitness watches and questionnaires will be used to control for key confounders in analyses. Primary outcomes are changes in aerobic fitness and muscle strength, as well as changes in skeletal muscle DNA methylation and gene expression profiles. Secondary outcomes include changes in skeletal muscle characteristics, proteomics, body composition and blood markers. Linear mixed models will be used to assess changes in outcomes, while accounting for repeated measures within participants and adjusting for known confounders. ETHICS AND DISSEMINATION: The Austin Health Human Research Ethics Committee (HREC) and Victoria University HREC granted approval for this study (HREC/77146/Austin-2021). Findings from this project will be published in open-access, peer-reviewed journals and presented to scientific and public audiences. TRIAL REGISTRATION NUMBER: ACTRN12621001415897; Pre-results.
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Pessoas Transgênero , Adulto , Estudos de Coortes , Hormônios , Humanos , Músculo Esquelético , Estudos Prospectivos , VitóriaRESUMO
AIM: Observed effects of exercise are highly variable between individuals, and subject-by-training interaction (i.e., individual response variability) is often not estimated. Here, we measured mitochondrial (citrate synthetase, cytochrome-c oxidase, succinate dehydrogenase, and mitochondrial copy-number), performance markers (Wpeak , lactate threshold [LT], and VO2peak ), and fiber type proportions/expression (type I, type IIa, and type IIx) in multiple time points during 12-week of high-intensity interval training (HIIT) to investigate effects of exercise at the individual level. METHODS: Sixteen young (age: 33.1 ± 9.0 years), healthy men (VO2peak 35-60 ml/min/kg and BMI: 26.4 ± 4.2) from the Gene SMART study completed 12-week of progressive HIIT. Performance markers and muscle biopsies were collected every 4 weeks. We used mixed-models and bivariate growth models to quantify individual response and to estimate correlations between variables. RESULTS: All performance markers exhibited significant (Wpeak 0.56 ± 0.33 p = 0.003, LT 0.37 ± 0.35 p = 0.007, VO2peak 3.81 ± 6.13 p = 0.02) increases overtime, with subject-by-training interaction being present (95% CI: Wpeak 0.09-0.24, LT 0.06-0.18, VO2peak 0.27-2.32). All other measurements did not exhibit significant changes. Fiber type IIa proportions at baseline was significantly associated with all physiological variables (p < 0.05), and citrate synthetase and cytochrome-c oxidase levels at baseline and overtime (i.e., intercept and slope) presented significant covariance (p < 0.05). Finally, low correlations between performance and mitochondrial markers were observed. CONCLUSION: We identified a significant subject-by-training interaction for the performance markers. While for all other measures within-subject variability was too large and interindividual differences in training efficacy could not be verified. Changes in measurements in response to exercise were not correlated, and such disconnection should be further investigated by future studies.
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Adaptação Fisiológica , Biomarcadores/metabolismo , Aptidão Cardiorrespiratória , Exercício Físico , Treinamento Intervalado de Alta Intensidade , Mitocôndrias/fisiologia , Consumo de Oxigênio , Adolescente , Adulto , Biomarcadores/análise , Humanos , Individualidade , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
The aim of this study was to investigate the relationship between mitochondrial content and respiratory function and whole-body insulin resistance in high-fat diet (HFD) fed rats. Male Wistar rats were given either a chow diet or an HFD for 12 weeks. After 4 weeks of the dietary intervention, half of the rats in each group began 8 weeks of interval training. In vivo glucose and insulin tolerance were assessed. Mitochondrial respiratory function was assessed in permeabilised soleus and white gastrocnemius (WG) muscles. Mitochondrial content was determined by the measurement of citrate synthase (CS) activity and protein expression of components of the electron transport system (ETS). We found HFD rats had impaired glucose and insulin tolerance but increased mitochondrial respiratory function and increased protein expression of components of the ETS. This was accompanied by an increase in CS activity in WG. Exercise training improved glucose and insulin tolerance in the HFD rats. Mitochondrial respiratory function was increased with exercise training in the chow-fed animals in soleus muscle. This exercise effect was absent in the HFD animals. In conclusion, exercise training improved insulin resistance in HFD rats but without changes in mitochondrial respiratory function and content. The lack of an association between mitochondrial characteristics and whole-body insulin resistance was reinforced by the absence of strong correlations between these measures. Our results suggest that improvements in mitochondrial respiratory function and content are not responsible for improvements in whole-body insulin resistance in HFD rats.
Assuntos
Resistência à Insulina/fisiologia , Mitocôndrias Musculares/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Respiração Celular/fisiologia , Dieta Hiperlipídica , Glucose/metabolismo , Insulina/metabolismo , Masculino , Músculo Esquelético/metabolismo , Obesidade/metabolismo , Obesidade/fisiopatologia , Ratos , Ratos WistarRESUMO
Nearly all human complex traits and diseases exhibit some degree of sex differences, with epigenetics being one of the main contributing factors. Various tissues display sex differences in DNA methylation; however, this has not yet been explored in skeletal muscle, despite skeletal muscle being among the tissues with the most transcriptomic sex differences. For the first time, we investigated the effect of sex on autosomal DNA methylation in human skeletal muscle across three independent cohorts (Gene SMART, FUSION, and GSE38291) using a meta-analysis approach, totalling 369 human muscle samples (222 males and 147 females), and integrated this with known sex-biased transcriptomics. We found 10,240 differentially methylated regions (DMRs) at FDR < 0.005, 94% of which were hypomethylated in males, and gene set enrichment analysis revealed that differentially methylated genes were involved in muscle contraction and substrate metabolism. We then investigated biological factors underlying DNA methylation sex differences and found that circulating hormones were not associated with differential methylation at sex-biased DNA methylation loci; however, these sex-specific loci were enriched for binding sites of hormone-related transcription factors (with top TFs including androgen (AR), estrogen (ESR1), and glucocorticoid (NR3C1) receptors). Fibre type proportions were associated with differential methylation across the genome, as well as across 16% of sex-biased DNA methylation loci (FDR < 0.005). Integration of DNA methylomic results with transcriptomic data from the GTEx database and the FUSION cohort revealed 326 autosomal genes that display sex differences at both the epigenome and transcriptome levels. Importantly, transcriptional sex-biased genes were overrepresented among epigenetic sex-biased genes (p value = 4.6e-13), suggesting differential DNA methylation and gene expression between male and female muscle are functionally linked. Finally, we validated expression of three genes with large effect sizes (FOXO3A, ALDH1A1, and GGT7) in the Gene SMART cohort with qPCR. GGT7, involved in antioxidant metabolism, displays male-biased expression as well as lower methylation in males across the three cohorts. In conclusion, we uncovered 8420 genes that exhibit DNA methylation differences between males and females in human skeletal muscle that may modulate mechanisms controlling muscle metabolism and health.
Assuntos
Epigenoma/fisiologia , Perfilação da Expressão Gênica/métodos , Músculo Esquelético/metabolismo , Fatores Sexuais , Ciclização de Substratos/fisiologia , Idoso , Feminino , Perfilação da Expressão Gênica/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologiaRESUMO
BACKGROUND: Knowledge of age-related DNA methylation changes in skeletal muscle is limited, yet this tissue is severely affected by ageing in humans. METHODS: We conducted a large-scale epigenome-wide association study meta-analysis of age in human skeletal muscle from 10 studies (total n = 908 muscle methylomes from men and women aged 18-89 years old). We explored the genomic context of age-related DNA methylation changes in chromatin states, CpG islands, and transcription factor binding sites and performed gene set enrichment analysis. We then integrated the DNA methylation data with known transcriptomic and proteomic age-related changes in skeletal muscle. Finally, we updated our recently developed muscle epigenetic clock (https://bioconductor.org/packages/release/bioc/html/MEAT.html). RESULTS: We identified 6710 differentially methylated regions at a stringent false discovery rate <0.005, spanning 6367 unique genes, many of which related to skeletal muscle structure and development. We found a strong increase in DNA methylation at Polycomb target genes and bivalent chromatin domains and a concomitant decrease in DNA methylation at enhancers. Most differentially methylated genes were not altered at the mRNA or protein level, but they were nonetheless strongly enriched for genes showing age-related differential mRNA and protein expression. After adding a substantial number of samples from five datasets (+371), the updated version of the muscle clock (MEAT 2.0, total n = 1053 samples) performed similarly to the original version of the muscle clock (median of 4.4 vs. 4.6 years in age prediction error), suggesting that the original version of the muscle clock was very accurate. CONCLUSIONS: We provide here the most comprehensive picture of DNA methylation ageing in human skeletal muscle and reveal widespread alterations of genes involved in skeletal muscle structure, development, and differentiation. We have made our results available as an open-access, user-friendly, web-based tool called MetaMeth (https://sarah-voisin.shinyapps.io/MetaMeth/).