Assuntos
Asma/genética , Metilação de DNA/genética , Predisposição Genética para Doença , Proteínas de Neoplasias/genética , Asma/imunologia , Asma/patologia , Linfócitos T CD4-Positivos/imunologia , Cromossomos Humanos Par 17/genética , Cromossomos Humanos Par 17/imunologia , Feminino , Estudos de Associação Genética , Humanos , Masculino , Linfócitos T/imunologia , Linfócitos T/patologiaRESUMO
The complex relationship between metabolic disease risk and body fat distribution in humans involves cellular characteristics which are specific to body fat compartments. Here we show depot-specific differences in the stromal vascual fraction of visceral and subcutaneous adipose tissue by performing single-cell RNA sequencing of tissue specimen from obese individuals. We characterize multiple immune cells, endothelial cells, fibroblasts, adipose and hematopoietic stem cell progenitors. Subpopulations of adipose-resident immune cells are metabolically active and associated with metabolic disease status and those include a population of potential dysfunctional CD8+ T cells expressing metallothioneins. We identify multiple types of adipocyte progenitors that are common across depots, including a subtype enriched in individuals with type 2 diabetes. Depot-specific analysis reveals a class of adipocyte progenitors unique to visceral adipose tissue, which shares common features with beige preadipocytes. Our human single-cell transcriptome atlas across fat depots provides a resource to dissect functional genomics of metabolic disease.
Assuntos
Tecido Adiposo/metabolismo , Doenças Metabólicas/metabolismo , Análise de Célula Única/métodos , Adipócitos/metabolismo , Tecido Adiposo/citologia , Adulto , Distribuição da Gordura Corporal , Feminino , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Doenças Metabólicas/patologia , Pessoa de Meia-Idade , Obesidade/metabolismoRESUMO
Lys-27-Met mutations in histone 3 genes (H3K27M) characterize a subgroup of deadly gliomas and decrease genome-wide H3K27 trimethylation. Here we use primary H3K27M tumor lines and isogenic CRISPR-edited controls to assess H3K27M effects in vitro and in vivo. We find that whereas H3K27me3 and H3K27me2 are normally deposited by PRC2 across broad regions, their deposition is severely reduced in H3.3K27M cells. H3K27me3 is unable to spread from large unmethylated CpG islands, while H3K27me2 can be deposited outside these PRC2 high-affinity sites but to levels corresponding to H3K27me3 deposition in wild-type cells. Our findings indicate that PRC2 recruitment and propagation on chromatin are seemingly unaffected by K27M, which mostly impairs spread of the repressive marks it catalyzes, especially H3K27me3. Genome-wide loss of H3K27me3 and me2 deposition has limited transcriptomic consequences, preferentially affecting lowly-expressed genes regulating neurogenesis. Removal of H3K27M restores H3K27me2/me3 spread, impairs cell proliferation, and completely abolishes their capacity to form tumors in mice.
Assuntos
Neoplasias Encefálicas/genética , Cromatina/metabolismo , Glioblastoma/genética , Histonas/genética , Complexo Repressor Polycomb 2/metabolismo , Adolescente , Idoso , Animais , Neoplasias Encefálicas/patologia , Sistemas CRISPR-Cas , Carcinogênese/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Criança , Ilhas de CpG/genética , Metilação de DNA/genética , Epigênese Genética , Feminino , Edição de Genes/métodos , Regulação Neoplásica da Expressão Gênica , Glioblastoma/patologia , Células HEK293 , Código das Histonas/genética , Histonas/metabolismo , Humanos , Lisina/genética , Masculino , Metionina/genética , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Mutação , Neurogênese/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: CpG methylation variation is involved in human trait formation and disease susceptibility. Analyses within populations have been biased towards CpG-dense regions through the application of targeted arrays. We generate whole-genome bisulfite sequencing data for approximately 30 adipose and blood samples from monozygotic and dizygotic twins for the characterization of non-genetic and genetic effects at single-site resolution. RESULTS: Purely invariable CpGs display a bimodal distribution with enrichment of unmethylated CpGs and depletion of fully methylated CpGs in promoter and enhancer regions. Population-variable CpGs account for approximately 15-20 % of total CpGs per tissue, are enriched in enhancer-associated regions and depleted in promoters, and single nucleotide polymorphisms at CpGs are a frequent confounder of extreme methylation variation. Differential methylation is primarily non-genetic in origin, with non-shared environment accounting for most of the variance. These non-genetic effects are mainly tissue-specific. Tobacco smoking is associated with differential methylation in blood with no evidence of this exposure impacting cell counts. Opposite to non-genetic effects, genetic effects of CpG methylation are shared across tissues and thus limit inter-tissue epigenetic drift. CpH methylation is rare, and shows similar characteristics of variation patterns as CpGs. CONCLUSIONS: Our study highlights the utility of low pass whole-genome bisulfite sequencing in identifying methylome variation beyond promoter regions, and suggests that targeting the population dynamic methylome of tissues requires assessment of understudied intergenic CpGs distal to gene promoters to reveal the full extent of inter-individual variation.