ABSTRACT: Assay for Transposase Accessible Chromatin by sequencing (ATAC-seq) provides an accurate way to depict the chromatin regulatory state and altered mechanisms guiding gene expression in disease. However bulk sequencing entangles information from different cell types and obscures cellular heterogeneity. Here, we develop and validate Cellformer, a novel deep learning method, that deconvolutes bulk ATAC-seq into cell type-specific expression across the whole genome. Cellformer enhances the bulk ATAC-seq resolution and allows an efficient cell type specific open chromatin profiling on large size cohorts at a low cost. Applied to 191 bulk samples from 3 brain regions, Cellformer identifies cell type-specific gene regulatory mechanisms and putative mediators involved in resilient to Alzheimer’s disease (RAD), an uncommon group of cognitively healthy individuals that harbor a high pathological load of Alzheimer’s disease (AD). Cell type-resolved chromatin profiling unveils cell type specific pathways and nominates potential epigenetic mediators underlying RAD that may illuminate therapeutic opportunities to limit the cognitive impact of this highly prevalent yet incurable disease. Cellformer has been made freely and publicly available to advance analysis of high-throughput bulk ATAC-seq in future investigations.
Project description:Bulk ATAC-seq was performed on fibroblasts from 8 different healthy mouse tissues such as bone, epididymal and inguinal fat pads, omentum, liver, lung and lymph node. This data was used to examine tissue specific chromatin landscapes in fibroblasts.
Project description:We report the application of the assay for transposase-accessible chromatin using sequencing (ATAC-seq) for the profiling of open chromatin human primary lung cell types implicated in lung disease pathology, such as chronic obstructive pulmonary disease. We generated chromatin accessibility profiles for human primary bronchial epithelial cells, small airway epithelial cells, alveolar type II pneumocytes, and lung fibroblasts using Omni-ATAC-seq. We further profiled open chromatin in a commonly used bronchial epithelial cell line (16HBE14o-) to evaluate the correlation with primary cell profiles and confirm the technical improvements using Omni-ATAC-seq vs Fast-ATAC-seq. We used these profiles to evaluate the enrichment of COPD risk variants in lung-specific open chromatin regions (OCRs) and generated cell type-specific regulatory predictions for >6,500 variants corresponding to 82 COPD GWAS loci.
Project description:The assay for transposase-accessible chromatin using sequencing (ATAC-seq) is widely used to identify regulatory regions throughout the genome. However, only a few studies have been done at the single cell level (scATAC-seq) due to technical difficulties. Here we developed a simple and robust plate-based scATAC-seq method, combining upfront bulk tagmentation with single-nuclei sorting, to investigate open chromatin regions. We applied this method on mouse splenocytes and unbiasedly revealed key regulatory regions and transcription factors that define each cell (sub)type.
Project description:The epigenome of human brain cells encompasses key information in understanding brain function in both healthy and diseased states. To further explore this, we used ATAC-seq to profile chromatin structure in four distinct populations of cells (glutamatergic neurons, GABAergic neurons, oligodendrocytes, and microglia/astrocytes), from three different regions of the brain. Chromatin accessibility was found to vary vastly by cell type and, more moderately, by brain region, with glutamatergic neurons showing the greatest regional variability. Transcription factor footprinting pointed to cell-specific transcriptional regulators and inferred cell-specific regulation of protein coding genes, long intergenic noncoding RNAs, and microRNAs. In vivo transgenic mouse experiments validated the cell type specificity of a number of human-derived regulatory sequences. Open chromatin regions in glutamatergic neurons were enriched for neuropsychiatric risk variants, particularly those associated with schizophrenia. Combining differential chromatin accessibility analysis using ATAC-seq data from bulk tissue increased our statistical power to confirm glutamatergic neurons as the cell type most affected in schizophrenia. Jointly, these findings illustrate the utility of studying the cell type specific epigenome in complex tissues such as the human brain and implicate an association among chromatin accessibility in glutamatergic neurons and genetic risk for schizophrenia.
Project description:We performed single-nucleus RNA sequencing of the dorsolateral prefrontal cortex from 15 normal, pathological aging, and Alzheimer’s disease human brains that varied by APOE and TREM2 genotype to analyze cell-type specific transcriptomic changes across the range of Alzheimer’s disease pathology and genetic risk factors.
Project description:The human cortex consists of a variety of different cell types. We used single-nuclei ATAC sequencing to characterize cell-type specific open chromatin profiles in a cohort of psychiatrically healthy controls and individuals diagnosed with psychiatric disease.
Project description:Recent advances in the development of single cell epigenomic assays have facilitated the analysis of the gene regulatory landscapes in complex biological systems. Single-cell variations of methods such as DNA methylation-sequencing and ATAC-seq hold tremendous promise for delineating distinct cell types and identifying their critical cis-regulatory sequences. Emerging evidence in recent years has shown that in addition to cis-regulatory sequences, dynamic regulation of 3D chromatin conformation is a critical mechanism for the modulation of gene expressions during development and disease. While assays for the investigation of single-cell 3D chromatin structure have been developed, cell-type specific chromatin conformation in primary human tissues has not been extensively explored. It remains unclear whether single-cell Chromatin Conformation Capture (3C) or Hi-C profiles are suitable for cell type identification and allow the reconstruction of cell-type specific chromatin conformation maps. To address these challenges, we have developed a multi-omic method single-nucleus methyl-3C sequencing (sn-m3C) to profile chromatin conformation and DNA methylation from the same cell. We have shown that bulk m3C and sn-m3C accurately capture chromatin organization information and robustly separate mouse cell types. We have developed a fluorescent-activated nuclei sorting strategy based on DNA content that eliminates nuclei multiplets caused by crosslinking. The sn-m3C-seq method allows high-resolution cell-type classification using two orthogonal types of epigenomic information and the reconstruction of cell-type specific chromatin conformation maps.
Project description:Restriction site Associated DNA (RAD) tags are a genome-wide representation of every site of a particular restriction enzyme by short DNA tags. Most organisms segregate large numbers of DNA sequence polymorphisms that disrupt restriction sites, which allow RAD tags to serve as genetic markers spread at a high-density throughout the genome. Here, we demonstrate the applicability of RAD markers for both individual and bulk-segregant genotyping. First, we show that these markers can be identified and typed on pre-existing microarray formats. Second, we present a method that uses RAD marker DNA to rapidly produce a low-cost microarray genotyping resource that can be used to efficiently identify and type thousands of RAD markers. We demonstrate the utility of the former approach by using a tiling path array for the fruit fly to map a recombination breakpoint, and the latter approach by creating and utilizing an enriched RAD marker array for the threespine stickleback. The high number of RAD markers enabled localization of a previously identified region, as well as a second novel region also associated with the lateral plate phenotype. Taken together, our results demonstrate that RAD markers, and the method to develop a RAD marker microarray resource, allow high-throughput, high-resolution genotyping in both model and non-model systems. Keywords: microarray genotyping
Project description:Bulk ATAC-seq was performed on human, chimpanzee, bonobo, and macaque stem cell-derived cerebral organoids. ATAC-seq was performed on day 60 (2 months old) and day 120 (4 months old) cerebral organoids.
Project description:We used bulk and single-cell ATAC-seq to measure chromatin accessibilty in human kidneys. This allowed us to define candidate cis-regulatory elements of each human kidney cell type and identify the role of podocyte and tubule regulatory elements in human kidney function.