Comparative analysis of chromatin accessibility during chondrogenesis and in osteoarthritis
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PROVIDER: PRJNA1127542 | ENA |
REPOSITORIES: ENA
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Project description:To reveal the organisation of the cartilage cell chondrocyte genome and identify changes that occur within this organisation during development and due to osteoarthritis (OA). Methods Assay for Transposase -Accessible Chromatin using Sequencing (ATAC-seq) was performed on chondrocytes isolated from 16 patients undergoing total hip replacement because of OA (n=7) or due to a neck of femur fracture (NOF, n=9). ATAC-seq was similarly performed on bone-marrow mesenchymal stem cells (BM-MSC) and differentiated chondrocytes of two donors. DNA sequence reads (av. 50 million/sample) were aligned to human genome Hg38. Peaks were called using MACS2 and differential accessibility identified by DiffBind. Interexperiment comparisons and intersection with published gene expression changes, chondrogenesis ChIP-seq, knee ATAC-seq and human tissue scATAC-seq were performed in Galaxy and R. OA GWAS signal regions were overlapped with our defined chondrocyte ATAC-seq peaks. Results In BM-MSC and derived chondrocytes we mapped 138005 open chromatin regions, of which 20979 and 50699 significantly increased and decreased respectively during cell differentiation. In hip chondrocytes we identified 115295 open chromatin regions, 1383 and 573 were more or less differentially accessible respectively when comparing OA with NOF samples. In both data sets ‘newly accessible regions were enriched at enhancer regions (defined by ChIP-seq). Comparing the data with the ATAC-seq from the single cell ATLAS we identified 11866 open regions exclusive to chondrocytes. Genes associated with these regions were significantly enriched for cartilage-related gene ontology terms. Taking the 420 OA GWAS signals present in the GWAS catalogue, 313 of the OA regions (defined as lead SNP + proxy SNPs with r2 ≥ 0.8) overlapped with a chondrocyte ATAC-seq region. Conclusions Here we have mapped chromatin accessible region changes during chondrogenesis, showing that newly accessible regions are enriched at enhancer regions and positively correlate with gene expression. Open chromatin region changes between OA and NOF cartilage were fewer, and peak differences were subtle. Overall, we have associated OA GWAS loci with accessible regions and defined regions of the genome specific to cartilage and chondrogenesis.
2025-01-01 | GSE270602 | GEO
Project description:Chromatin accessibility landscape of articular knee cartilage reveals aberrant enhancer regulation in osteoarthritis
| PRJNA423060 | ENA
Project description:Loss-of-function mutations in genes coding for subunits of the large, multifarious BRG1/BRM associated factor (BAF) chromatin remodeling complexes are frequently causative for cancer or developmental diseases1-5. Cells lacking the most frequently mutated subunits like the ATPase SMARCA4 typically exhibit drastic chromatin accessibility changes, especially of important regulatory regions6-12. However, so far it remains unknown how these changes are established over time, and whether they are causative for intra-complex synthetic lethalities abrogating the formation (SMARCC1-SMARCC2)8,13,14 or activity (SMARCA4-SMARCA2)15-17 of BAF complexes. Here, we utilize the dTAG system18 to induce acute degradation of BAF subunits in wild-type and BAF mutant backgrounds and analyze the resulting chromatin accessibility changes with high kinetic resolution. We observe that chromatin alterations are established faster than the duration of one cell cycle and that maintaining genome accessibility requires constant ATP-dependent remodeling. Completely abolishing BAF complex function by acute degradation of a synthetic lethal subunit in a paralog-deficient background results in a near-complete loss of chromatin accessibility at BAF-controlled sites, especially at super-enhancers, providing a mechanism for intra-complex synthetic lethalities.
2020-12-23 | PXD018381 | Pride
Project description:Dynamic chromatin accessibility tuning of long noncoding RNA ELDR accelerates chondrocyte senescence and osteoarthritis
| PRJNA737345 | ENA
Project description:Chromatin organization is a highly orchestrated process that influences gene expression, in part by modulating access of regulatory factors to DNA and nucleosomes. We found that the chromatin accessibility regulator HMGN1, a target of recurrent DNA copy gains in leukemia, controls myeloid differentiation. HMGN1 amplification was associated with increased accessibility, expression, and histone H3K27 acetylation of loci important for hematopoietic stem cell (HSC) function and AML, such as HoxA cluster genes. In vivo, HMGN1 overexpression was linked to decreased quiescence and increased HSC activity in bone marrow transplantation. HMGN1 overexpression also cooperated with the AML-ETO9a fusion oncoprotein to impair myeloid differentiation and enhance leukemia stem cell (LSC) activity. Inhibition of histone acetyltransferases CBP/p300 relieved the HMGN1-associated differentiation block. These data nominate factors that modulate chromatin accessibility as regulators of HSCs and LSCs and suggest that targeting HMGN1 or its downstream effects on histone acetylation could be therapeutically active in AML.
2020-02-25 | PXD017054 | Pride
Project description:Cells can deform their local microenvironment by exerting forces through pushing and pulling. Such interactions result in behaviors such as cell spreading, cell migration, or cell volume expansion, which occur on timescales of hours to days. However, whether cells can deform local niches at shorter timescales and how such interactions impact long-term cell fates remain largely unknown. Here we report “cell dancing”- a previously unknown cell behavior characterized by seconds-to-minutes scale deformation of the pericellular niche and enhanced cytoskeletal and nuclear dynamics. Using hydrogels that allow cells to deform their local 3D niche and mesenchymal stem cell chondrogenesis as a model system, we identify early-stage cell dancing essential for enhancing stem cell differentiation in 3D. This is mediated through nuclear mechanotransduction pathways that repress global chromatin accessibility, which is necessary for cell dancing-enhanced differentiation. We further demonstrate that cell dancing induces nuclear deformations and phospholipase A2 (PLA2) signaling, and small molecules targeting this pathway can further boost stem cell chondrogenesis. Finally, we validate that cell dancing can enhance stem cell differentiation towards multiple lineages and occurs in other commonly used hydrogel systems. These results establish cell dancing as a novel cell behavior in 3D that may be broadly applied to promote desirable cell fates and tissue outcomes.
2024-06-29 | GSE239277 | GEO
Project description:Osteoarthritis is a devastating disease of articular cartilage. The pathogenic factors contributing to this disorder are inflammation, extracellular matrix degradation and failure to rebuild the articular cartilage. Preclinical studies suggest that microRNA-140 (miR-140) may play a protective role in osteoarthritis development, but little is known about the mechanism by which this may occur. Here we present the results of overexpression of miR-140 in an in vitro model of osteoarthritis, evaluated by global proteomics analysis. We show that inflammation is reduced through the differential synthesis of multiple proteins involved in the nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB) pathway, articular cartilage regeneration may be induced through the upregulation of many of the components involved in the synthesis of hyaline extracellular matrix, and cartilage degeneration may be reduced through the reduced expression of aggrecanases. Thus, miR-140 overexpression may have a beneficial effect on the development of osteoarthritis through the differential synthesis of a surprisingly large number of proteins involved in all three pathogenic processes. These results show how intraarticular injection of miR-140 may benefit patients suffering from osteoarthritis.
2018-10-26 | PXD003362 | Pride
Project description:Regulation of transcription occurs in a cell type specific manner orchestrated by epigenetic mechanisms including DNA methylation. Methylation changes may also play a key role in lineage specification during stem cell differentiation. To further our understanding of epigenetic regulation in chondrocytes we characterised DNA methylation changes during chondrogenesis of mesenchymal stem cells (MSCs) by Infinium 450K methylation array. Significant DNA hypomethylation was identified during chondrogenesic differentiation including changes at many key cartilage gene loci. Integration with chondrogenesis gene expression data revealed an enrichment of significant CpGs in upregulated genes, while characterisation of significant CpG loci indicated their predominant localisation to enhancer regions. Comparison with methylation profiles of other tissues, including healthy and diseased adult cartilage, identified chondrocyte-specific regions of hypomethylation and the overlap with differentially methylated CpGs in osteoarthritis. Taken together we have associated DNA methylation levels with the chondrocyte phenotype. The consequences of which has potential to improve cartilage generation for tissue engineering purposes and also to provide context for observed methylation changes in cartilage diseases such as osteoarthritis
2019-05-24 | GSE129266 | GEO
Project description:<p>Non-coding regions comprise most of the human genome and harbor a significant fraction of risk alleles for neuropsychiatric diseases, yet their functions remain poorly defined. We created a high-resolution map of non-coding elements involved in human cortical neurogenesis by contrasting chromatin accessibility and gene expression in the germinal zone and cortical plate of the developing cerebral cortex. To obtain a high resolution depiction of chromatin structure and gene expression in developing human fetal cortex, we dissected the post-conception week (PCW) 15-17 human neocortex into two major anatomical divisions to distinguish between proliferating neural progenitors and post mitotic neurons: (1) GZ: the neural progenitor-enriched region encompassing the ventricular zone (VZ), subventricular zone (SVZ), and intermediate zone (IZ) and (2) CP: the neuron-enriched region containing the subplate (SP), cortical plate (CP), and marginal zone (MZ). Tissues were obtained from three independent donors and three to four technical replicates from each tissue were processed for ATAC-seq to define the landscape of accessible chromatin and RNA-seq for genome-wide gene expression profiling.</p>
| phs001438 | dbGaP
Project description:Regulation of gene expression is linked to the organization of the genome. With age, chromatin alterations occur on all levels of genome organization, accompanied by changes in the gene expression profile. However, little is known about the changes on the level of transcriptional regulation. Here, we used a multi-omics approach and integrated ATAC-, RNA- and NET-seq to identify age-related changes in the chromatin landscape of murine liver and to investigate how these are linked to transcriptional regulation. We provide the first systematic inventory of the connection between aging, chromatin accessibility and transcriptional regulation in a whole tissue. Aging in murine liver is characterized by an increase in chromatin accessibility at promoter regions, but not in an increase of transcriptional output. Instead, aging is accompanied by a decrease of promoter-proximal pausing of RNA polymerase II (Pol II). We propose that these changes in transcriptional regulation are due to a reduced stability of the pausing complex and may represent a mechanism to compensate for the age-related increase in chromatin accessibility in order to prevent aberrant transcription.
2022-09-15 | PXD034564 | Pride