Search bioRxiv⌕ Search

Biology subjects

Burant, C. F.

Publications and source records attributed to Burant, C. F..

12 recordsLinked to original sources

Integrative Multi-omics Analysis of the Human Skeletal Muscle Response to Endurance or Resistance Exercise: Findings from the Molecular Transducers of Physical Activity Consortium (MoTrPAC)

The Molecular Transducers of Physical Activity Consortium (MoTrPAC) was established to systematically characterize the molecular basis of the health benefits of exercise. Here, we present the integrative, multi-omics response of human skeletal muscle to acute endurance (EE) and resistance (RE) exercise. Distinct temporal responses were observed, with changes in ATAC-seq, phosphoproteome, and metabolome occurring before changes in the transcriptome and proteome. These distinct temporal multi-omic dynamics were used to identify transcriptional regulatory hubs converging around MEF2A and NFIC regulation of autophagy, angiogenesis and metabolism. Further, early RE-specific phosphoproteome signatures counteracted epigenetic modifications and downregulated transcripts involved in protein turnover. Additional findings include suppression of HIPK2/3 kinase signatures linked to the acute exercise regulation of sarcomeric proteins TTN, NEB, ANKRD2 and LMOD2. Our data demonstrate distinct temporal regulation across the multi-omic landscape of human skeletal muscle, with EE and RE eliciting common and unique molecular signatures.

systems biology↗

Molecular Transducers of Physical Activity Consortium (MoTrPAC): Initial Insights into the Dynamic Human Responses to Exercise

The goal of the Molecular Transducers of Physical Activity Consortium (MoTrPAC) is to examine the physiological and molecular basis for health benefits in response to acute and chronic exercise. Prior to COVID-19 suspension, healthy, sedentary participants (N=206, 18-74y) were randomized to endurance exercise (N=80), resistance exercise (N=81), or non-exercise control (N=45) interventions. The prescribed vigorous acute endurance and resistance exercise bouts induced physiological and metabolic perturbations relative to resting homeostasis. The supervised chronic (3d/wk, 12wk) endurance or resistance training programs robustly improved several physiological parameters (i.e., VO2peak, muscular strength). Temporal biospecimen (blood, muscle, and adipose) collections and processing coupled to the acute exercise bouts were highly successful. In most cases, over 90% success was achieved for blood, muscle, and adipose samples. Endurance and resistance exercise induced distinct acute and chronic physiological responses, which provide a framework to interrogate the molecular basis for health adaptations to these two popular exercise modalities. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/705347v1_ufig1.gif" ALT="Figure 1"> View larger version (65K): org.highwire.dtl.DTLVardef@554ee9org.highwire.dtl.DTLVardef@afb28dorg.highwire.dtl.DTLVardef@f381cdorg.highwire.dtl.DTLVardef@cef19c_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗

Blood Biochemical Responses to Acute Exercise: Findings from the Molecular Transducers of Physical Activity Consortium (MoTrPAC)

Exercise benefits numerous organ systems and tissues, however limited knowledge exists about its underlying molecular pathways. Identifying the exercise-induced biochemical changes that occur in the circulation may provide further insights into how exercise confers systemic health changes. Here, we perform large-scale plasma proteomic, metabolomic, and whole blood transcriptional profiling in sedentary human participants undergoing acute endurance exercise (EE), resistance exercise (RE), or a non-exercise control (CON) in up to 7 timepoints over a 24 hour period. We observe 7066 transcript, 189 protein, and 448 metabolite changes in response to EE or RE compared to CON. Our analyses reveal numerous shared biochemical responses between EE and RE modes, but also differences in immune cell responses, lipid metabolism, and pathways reflective of tissue repair and angiogenesis. Taken together, our findings highlight novel temporal and exercise mode-specific blood-based molecular responses to acute exercise, and provide a new resource for the scientific community.

systems biology↗

Exercise modulation of the alternative splicing landscape in human tissues

The diverse health benefits of exercise are associated with multi-organ molecular responses. Alternative RNA splicing (AS) is an important determinant of transcriptome and proteome diversity. We profiled the temporal effects of acute endurance and resistance exercise on the AS landscape of human skeletal muscle, adipose tissue, and blood, and studied regulatory mechanisms through integrated multi-omic analyses. We identified 5102 distinct differential AS (DAS) events, with the majority modifying protein-coding sequence (89%) and being independent of altered RNA expression (67%). Endurance and resistance exercise induced differing patterns of AS alterations with divergent temporal trajectories. We inferred the DAS-associated RNA-binding and DNA-binding proteins. In skeletal muscle, where DAS events were the most abundant, DAS genes were enriched for muscle structure- and RNA splicing-related processes, and splicing machinery components were regulated at the protein phosphorylation, RNA, and AS levels. These findings implicate AS regulation as a major mediator of the responses to exercise.

systems biology↗

Temporal Multi-Omic Analysis Uncovers Sex-Biased Molecular Programs Underlying Skeletal Muscle Adaptation to Endurance Training

BackgroundExercise training is known to benefit health and reduce disease risk. While skeletal muscle adaptations are fundamental to many of the health benefits of exercise training, the common and sex-specific molecular regulators that mediate these adaptations remain to be fully elucidated. MethodsTo this end, we leveraged skeletal muscle multi-omics data generated by the Molecular Transducers of Physical Activity Consortium (MoTrPAC), where 6 month-old male and female rats endurance trained for 1, 2, 4, or 8 weeks. Our objective was to identify shared and sex-specific multi-omic molecular responses to endurance training in skeletal muscle, and relate them to phenotypic adaptations. ResultsWe identified largely sexually-conserved transcriptomic and proteomic pathway enrichments in the gastrocnemius, which correlated with skeletal muscle responses from a published exercise study in humans. We uncovered sex-consistent post-translational modifications, including decreased oxidation of MYH2 and deacetylation of the {beta}-oxidation enzyme HADHA. Pathway enrichment analyses revealed sex-specific remodeling across the acetylome, redox proteome, and phosphoproteome; females decreased mitochondrial protein cysteine oxidation and increased mitochondrial cristae proteins, indicative of enhanced redox buffering and mitochondrial efficiency. Despite decreases in cysteine oxidation of key mitochondrial proteins, females displayed increases in the cysteine oxidation of proteins involved in glucose catabolism relative to males after 8 weeks of training, suggestive of sex-biased subcellular reactive oxygen species generation. Males demonstrated earlier induction of mitochondrial transcripts and predicted activation of mTOR. Although the increase in mitochondrial protein abundance was more modest in males, there was greater oxidation of mitochondrial proteins in response to training compared to females. ConclusionsThis work shows a large portion of the adaptive response to endurance training in skeletal muscle is shared between females and males, while there are distinct and nuanced sex-specific adaptations that are evident, particularly at the level of post-translational regulation.

physiology↗

Integrative multi-omics uncovers skeletal muscle enhancer programming of cardiorespiratory fitness

Cardiorespiratory fitness (CRF) is a heritable trait associated with improved metabolic health and longevity. To identify regulatory mechanisms underlying CRF, we integrated 546 transcriptomic and epigenomic profiles from skeletal muscle of 128 genetically heterogeneous rats selectively bred for high and low running capacity, a model that mirrors CRF-associated traits in humans. Selection drove genetic convergence in coordinated skeletal muscle enhancer networks linked to lipid metabolism and angiogenesis genes. We validated thousands of these genetic effects through integration of 426 genotype, gene expression, and chromatin accessibility profiles in an independent HCRxLCR F2 population (n=147). These 972 multi-omics profiles show that CRF-associated genetic variation reshapes the chromatin landscape to support energy metabolism and oxygen delivery, offering a molecular framework for identifying targets to reduce cardiometabolic disease risk. Glossary of TermsO_LIModality/modalities: essentially a dataset. A modality can refer to one or multiple of ATAC-Seq, H3K27ac & additional histone modifications, chromatin states such as Strong Enhancer, and/or RNA-Seq C_LIO_LIPeaks: only refers to ATAC-Seq and CUT&Tag data C_LIO_LIFeatures: can collectively refer to genomic regions of one or more modality classes (genes, peaks, and/or chromatin state regions) C_LIO_LIVariant(s): SNP(s) C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/679855v2_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@1ee52eorg.highwire.dtl.DTLVardef@5848b7org.highwire.dtl.DTLVardef@debaforg.highwire.dtl.DTLVardef@1ec43ba_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

Lipidomics profiling identifies β-oxidation as a key process in noise-induced hearing loss

Noise-induced hearing loss (NIHL) is the second leading cause of hearing loss worldwide, and the most common cause in young adults. Despite this burden, the molecular mechanisms by which noise causes damage are poorly understood, and there are no pharmacologic therapies to prevent or reduce noise-induced damage to the inner ear. Here, using targeted and untargeted lipidomics, we show that noise exposure induces changes in fatty acid (FA) and acylcarnitine (CAR) species in the inner ear, a metabolic profile indicative of noise-induced increases in {beta}- oxidation. This conclusion is validated through treatment with Etomoxir, an inhibitor of carnitine palmitoyltransferase 1A, the rate-limiting enzyme of long-chain {beta}-oxidation. Furthermore, we demonstrate that blocking {beta}-oxidation with Etomoxir does not affect hearing in a normal acoustic environment but reduces the extent of hearing loss induced by an intense noise exposure (2 hours, 112 dB SPL, 8-16kHz). Together, our findings provide insights into cochlear energy metabolism and suggest that its modulation could be targeted to reduce NIHL.

neuroscience↗

Population-scale skeletal muscle single-nucleus multi-omic profiling reveals extensive context specific genetic regulation

Skeletal muscle, the largest human organ by weight, is relevant in several polygenic metabolic traits and diseases including type 2 diabetes (T2D). Identifying genetic mechanisms underlying these traits requires pinpointing cell types, regulatory elements, target genes, and causal variants. Here, we use genetic multiplexing to generate population-scale single nucleus (sn) chromatin accessibility (snATAC-seq) and transcriptome (snRNA-seq) maps across 287 frozen human skeletal muscle biopsies representing nearly half a million nuclei. We identify 13 cell types and integrate genetic variation to discover >7,000 expression quantitative trait loci (eQTL) and >100,000 chromatin accessibility QTLs (caQTL) across cell types. Learning patterns of e/caQTL sharing across cell types increased precision of effect estimates. We identify high-resolution cell-states and context-specific e/caQTL with significant genotype by context interaction. We identify nearly 2,000 eGenes colocalized with caQTL and construct causal directional maps for chromatin accessibility and gene expression. Almost 3,500 genome-wide association study (GWAS) signals across 38 relevant traits colocalize with sn-e/caQTL, most in a cell-specific manner. These signals typically colocalize with caQTL and not eQTL, highlighting the importance of population-scale chromatin profiling for GWAS functional studies. Finally, our GWAS-caQTL colocalization data reveal distinct cell-specific regulatory paradigms. Our results illuminate the genetic regulatory architecture of human skeletal muscle at high resolution epigenomic, transcriptomic, and cell-state scales and serve as a template for population-scale multi-omic mapping in complex tissues and traits.

genomics↗

The mitochondrial multi-omic response to exercise training across tissues

Mitochondria are adaptable organelles with diverse cellular functions critical to whole-body metabolic homeostasis. While chronic endurance exercise training is known to alter mitochondrial activity, these adaptations have not yet been systematically characterized. Here, the Molecular Transducers of Physical Activity Consortium (MoTrPAC) mapped the longitudinal, multi-omic changes in mitochondrial analytes across 19 tissues in male and female rats endurance trained for 1, 2, 4 or 8 weeks. Training elicited substantial changes in the adrenal gland, brown adipose, colon, heart and skeletal muscle, while we detected mild responses in the brain, lung, small intestine and testes. The colon response was characterized by non-linear dynamics that resulted in upregulation of mitochondrial function that was more prominent in females. Brown adipose and adrenal tissues were characterized by substantial downregulation of mitochondrial pathways. Training induced a previously unrecognized robust upregulation of mitochondrial protein abundance and acetylation in the liver, and a concomitant shift in lipid metabolism. The striated muscles demonstrated a highly coordinated response to increase oxidative capacity, with the majority of changes occurring in protein abundance and post-translational modifications. We identified exercise upregulated networks that are downregulated in human type 2 diabetes and liver cirrhosis. In both cases HSD17B10, a central dehydrogenase in multiple metabolic pathways and mitochondrial tRNA maturation, was the main hub. In summary, we provide a multi-omic, cross-tissue atlas of the mitochondrial response to training and identify candidates for prevention of disease-associated mitochondrial dysfunction.

molecular biology↗

Human and rat skeletal muscle single-nuclei multi-omic integrative analyses nominate causal cell types, regulatory elements, and SNPs for complex traits

BackgroundSkeletal muscle accounts for the largest proportion of human body mass, on average, and is a key tissue in complex diseases, mobility, and quality of life. It is composed of several different cell and muscle fiber types. ResultsHere, we optimize single-nucleus ATAC-seq (snATAC-seq) to map skeletal muscle cell-specific chromatin accessibility landscapes in frozen human and rat samples, and single-nucleus RNA-seq (snRNA-seq) to map cell-specific transcriptomes in human. We capture type I and type II muscle fiber signatures, which are generally missed by existing single-cell RNA-seq methods. We perform cross-modality and cross-species integrative analyses on 30,531 nuclei, representing 11 libraries, profiled in this study, and identify seven distinct cell types ranging in abundance from 63% (type II fibers) to 0.9% (muscle satellite cells) of all nuclei. We introduce a regression-based approach to infer cell types by comparing transcription start site-distal ATAC-seq peaks to reference enhancer maps and show consistency with RNA-based marker gene cell type assignments. We find heterogeneity in enrichment of genetic variants linked to complex phenotypes from the UK Biobank and diabetes genome wide association studies in cell-specific ATAC-seq peaks, with the most striking enrichment patterns in muscle mesenchymal stem cells ([~]3% of nuclei). Finally, we overlay these chromatin accessibility maps on GWAS data to nominate causal cell types, SNPs, and transcription factor motifs for creatinine levels and type 2 diabetes signals. ConclusionsThese chromatin accessibility profiles for human and rat skeletal muscle cell types are a useful resource for investigating specific cell types and nominating causal GWAS SNPs and cell types.

genomics↗

The role of elevated branched chain amino acids in the potent effects of vertical sleeve gastrectomy to reduce weight and improve glucose regulation in mice

Obesity and type 2 diabetes mellitus (T2D) are growing epidemics resulting in increased morbidity and mortality. An emerging body of evidence has shown that elevated levels of branched-chain amino acids (BCAA) and their metabolites are strongly positively associated with obesity, insulin-resistance and T2D. Bariatric surgery is among the best treatments for weight loss and the alleviation of T2D. Additionally, clinical studies have reported that bariatric surgery decreases the circulating levels of BCAA. The objective of these studies was to test the hypothesis that reduced BCAA levels contribute to the metabolic improvements after VSG. We find that, as in humans, circulating BCAA levels are significantly lower in VSG rats and mice compared to Sham controls. In order to increase circulating BCAA levels, we tested mice with either increased dietary intake of BCAA or impaired BCAA catabolism by total body deletion of mitochondrial phosphatase 2C, Pp2cm, a key enzyme in the rate-limiting step in BCAA catabolism. Our results show that a decrease in circulating BCAA levels is not necessary for sustained body weight loss and improved glucose tolerance after VSG. While it is clear that circulating levels of BCAAs are excellent biomarkers for metabolic status, the current data do not support a causal role in determining metabolic regulation and the response to VSG.

physiology↗

Mitochondrial PE potentiates respiratory enzymes to amplify skeletal muscle aerobic capacity

Exercise capacity is a strong predictor of all-cause mortality. Skeletal muscle mitochondrial respiratory capacity, its biggest contributor, adapts robustly to changes in energy demands induced by contractile activity. While transcriptional regulation of mitochondrial enzymes has been extensively studied, there is limited information on how mitochondrial membrane lipids are regulated. Herein, we show that exercise training or muscle disuse alters mitochondrial membrane phospholipids including phosphatidylethanolamine (PE). Addition of PE promoted, whereas removal of PE diminished, mitochondrial respiratory capacity. Surprisingly, skeletal muscle-specific inhibition of mitochondrial-autonomous synthesis of PE caused a respiratory failure due to metabolic insults in the diaphragm muscle. While mitochondrial PE deficiency coincided with increased oxidative stress, neutralization of the latter did not rescue lethality. These findings highlight the previously underappreciated role of mitochondrial membrane phospholipids in dynamically controlling skeletal muscle energetics and function.

physiology↗