Reprogramming of Cis-regulatory networks during skeletal muscle atrophy [snATAC-seq]
Ontology highlight
ABSTRACT: Current atlas of regulatory sequences controlling skeletal muscle atrophy are still incomplete and lack cell type resolution. We applied single-cell chromatin accessibility assays (snATAC) to normal and denervated skeletal muscle from mice. We integrated these snATAC datasets with our single-nucleus RNA-sequence dataset to reveal the status of open chromatin. Using these datasets, we delineated chromatin accessibility maps in both normal and atrophic muscles and identified cis-regulatory elements (CREs) in all type of cell in skeletal muscle that may regulating muscle protein metabolism, energy metabolism and transcription activities, thus, provided a rich resource for understanding gene regulatory programs in skeletal muscle and related disorders.
Project description:The epigenomic regulation is a part of Gene Regulatory Network (GRN). During we study the reprogramming of GRN adaptive to atrophic stimulation in skeletal muscle, we performed Histone 3 lysine 27 (H3K27) acetylation (H3K27ac) ChIP-seq assay using mouse skeletal muscle with or without denervation. This dataset combining with our snATAC datasets enable us to infer the candidate enhancer that could regulate muscle protein metabolism and energy metabolism during atrophy.
Project description:Skeletal muscle accounts for the largest proportion of human body mass, on average, and is a key tissue in complex diseases and mobility. It is composed of several different cell and muscle fiber types. Here, 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 additionally perform multi-omics profiling (gene expression and chromatin accessibility) on human and rat muscle samples.
Project description:This study used droplet-based snATAC-seq to profile the chromatin accessibility landscape of 91,922 nuclei in the mouse cerebellum across eleven developmental stages, from the beginning of neurogenesis (e10.5) till adulthood (P63). The study included two biological replicates per stage, one from each sex. Cerebelli were dissected as whole or in two halves, nuclei were extracted and profiled using 10x single-cell ATAC reagent kit (v1.0) and a Chromium controller. Libraries were sequenced using paired-reads on Illumina NextSeq 550 and initial data processing was performed using Cellranger ATAC (1.1).
Project description:Skeletal muscle accounts for the largest proportion of human body mass, on average, and is a key tissue in complex diseases and mobility. It is composed of several different cell and muscle fiber types. Here, 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 additionally perform multi-omics profiling (gene expression and chromatin accessibility) on human and rat muscle samples. 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 33,862 nuclei and identify seven cell types ranging in abundance from 59.6% to 1.0% 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 (~3.5% of nuclei). Finally, we overlay these chromatin accessibility maps on GWAS data to nominate causal cell types, SNPs, transcription factor motifs, and target genes for type 2 diabetes signals. These chromatin accessibility profiles for human and rat skeletal muscle cell types are a useful resource for nominating causal GWAS SNPs and cell types.
Project description:This study used droplet-based snATAC-seq to profile the chromatin accessibility landscape of 19,204 nuclei in the opossum (Monodelphis domestical) cerebellum across two developmental stages (postnatal day 21 and adult). The study included two biological replicates per stage, one from each sex, and an additional adult sample enriched for white matter. Cerebelli were dissected in two halves, nuclei were extracted from one half and profiled using 10x single-cell ATAC reagent kit (v1.1) and a Chromium controller. The white matter enriched sample was dissected from coronal cerebellum slices. Libraries were sequenced using paired-reads on Illumina NextSeq 550 and initial data processing was performed using Cellranger ATAC (1.1).
Project description:Innervation of skeletal muscle fibers plays a crucial role in the maintenance of muscle tone and normal functioning, but little is known to date about denervated muscle atrophy and its underlying mechanisms. To this end, we performed RNA sequencing of skeletal muscle from sciatic nerve-excised C57BL/6 and BALB/c mice to investigate the underlying mechanisms of denervated skeletal muscle atrophy.
Project description:We have performed parallel scRNA-seq and snATAC-seq analysis of skeletal muscles subjected to sciatic nerve transection to delineate cell type-specific patterns of gene expression and chromatin accessibility at different time-points post-denervation. This analysis revealed that, unlike muscle injury, denervation leads to the selective activation of specific muscle-resident cell types, such as glial cells and a population of mesenchymal cells marked by the expression of Thy1/CD90.
Project description:Samples of denervated GA muscle were compared to contralateral controls to determine transcriptional changes associated with skeletal muscle denervation.
Project description:Ammonia is a cytotoxic molecule generated during cellular functions and by the gut microbiome. Dysregulated ammonia metabolism initiates a hyperammonemic stress response (HASR). Hyperammonemia occurs in many chronic diseases but there is limited understanding of the overall consequences of HASR. A comprehensive array of unbiased approaches was used to identify global responses during hyperammonemia with experimental validation of critical findings. Protein/gene expression and chromatin accessibility in hyperammonemic murine myotubes and mouse skeletal muscle tissue were analyzed by quantitative proteomics, RNA sequencing (RNAseq), and Assay for Transposase Accessible Chromatin Sequencing (ATACseq). Unique clusters of expression/accessibility changes were identified in hyperammonemic myotubes. In hyperammonemic mouse muscle and myotubes, we identified enrichment of pathways involved in oxidative phosphorylation, calcium signaling, hypoxia inducible factor-1, and apoptosis and regulation of protein synthesis were altered during HASR and were experimentally validated. Enrichment of senescence signaling and glycosylation pathways during HASR were novel observations. Comparisons with RNAseq data from skeletal muscle from human patients with cirrhosis revealed similar perturbations, demonstrating the translational relevance of our observations. We identified several novel regulatory pathways during HASR that are conserved in different models and across species, and whose dysregulation could significantly impact skeletal muscle structure and function.