Profiling the genetic determinants of chromatin accessibility with scalable single-cell CRISPR screens

2021 ◽  
Author(s):  
Noa Liscovitch-Brauer ◽  
Antonino Montalbano ◽  
Jiale Deng ◽  
Alejandro Méndez-Mancilla ◽  
Hans-Hermann Wessels ◽  
...  
Keyword(s):  
Single Cell ◽  
Chromatin Accessibility ◽  
Genetic Determinants

scholarly journals High-throughput single-cell chromatin accessibility CRISPR screens enable unbiased identification of regulatory networks in cancer

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sarah E. Pierce ◽  
Jeffrey M. Granja ◽  
William J. Greenleaf
Keyword(s):  
Transcription Factor ◽  
Single Cell ◽  
Cancer Cells ◽  
High Throughput ◽  
Regulatory Networks ◽  
Temporal Dynamics ◽  
Chromatin Accessibility ◽  
Regulatory Regions ◽  
Factor Binding ◽  
Genome Wide

AbstractChromatin accessibility profiling can identify putative regulatory regions genome wide; however, pooled single-cell methods for assessing the effects of regulatory perturbations on accessibility are limited. Here, we report a modified droplet-based single-cell ATAC-seq protocol for perturbing and evaluating dynamic single-cell epigenetic states. This method (Spear-ATAC) enables simultaneous read-out of chromatin accessibility profiles and integrated sgRNA spacer sequences from thousands of individual cells at once. Spear-ATAC profiling of 104,592 cells representing 414 sgRNA knock-down populations reveals the temporal dynamics of epigenetic responses to regulatory perturbations in cancer cells and the associations between transcription factor binding profiles.

scholarly journals Single cell transcriptome atlas of mouse mammary epithelial cells across development

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Bhupinder Pal ◽  
Yunshun Chen ◽  
Michael J. G. Milevskiy ◽  
François Vaillant ◽  
Lexie Prokopuk ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Single Cell ◽  
Developmental Stages ◽  
Mammary Epithelial Cells ◽  
Expression Profiles ◽  
Single Cells ◽  
Chromatin Accessibility ◽  
Mammary Epithelial ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

Abstract Background Heterogeneity within the mouse mammary epithelium and potential lineage relationships have been recently explored by single-cell RNA profiling. To further understand how cellular diversity changes during mammary ontogeny, we profiled single cells from nine different developmental stages spanning late embryogenesis, early postnatal, prepuberty, adult, mid-pregnancy, late-pregnancy, and post-involution, as well as the transcriptomes of micro-dissected terminal end buds (TEBs) and subtending ducts during puberty. Methods The single cell transcriptomes of 132,599 mammary epithelial cells from 9 different developmental stages were determined on the 10x Genomics Chromium platform, and integrative analyses were performed to compare specific time points. Results The mammary rudiment at E18.5 closely aligned with the basal lineage, while prepubertal epithelial cells exhibited lineage segregation but to a less differentiated state than their adult counterparts. Comparison of micro-dissected TEBs versus ducts showed that luminal cells within TEBs harbored intermediate expression profiles. Ductal basal cells exhibited increased chromatin accessibility of luminal genes compared to their TEB counterparts suggesting that lineage-specific chromatin is established within the subtending ducts during puberty. An integrative analysis of five stages spanning the pregnancy cycle revealed distinct stage-specific profiles and the presence of cycling basal, mixed-lineage, and 'late' alveolar intermediates in pregnancy. Moreover, a number of intermediates were uncovered along the basal-luminal progenitor cell axis, suggesting a continuum of alveolar-restricted progenitor states. Conclusions This extended single cell transcriptome atlas of mouse mammary epithelial cells provides the most complete coverage for mammary epithelial cells during morphogenesis to date. Together with chromatin accessibility analysis of TEB structures, it represents a valuable framework for understanding developmental decisions within the mouse mammary gland.

scholarly journals RA3 is a reference-guided approach for epigenetic characterization of single cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shengquan Chen ◽  
Guanao Yan ◽  
Wenyu Zhang ◽  
Jinzhao Li ◽  
Rui Jiang ◽  
...  
Keyword(s):  
Single Cell ◽  
Computational Analysis ◽  
Reference Data ◽  
Single Cells ◽  
Chromatin Accessibility ◽  
Biological Variation ◽  
Superior Performance ◽  
High Dimensionality ◽  
High Degree

AbstractThe recent advancements in single-cell technologies, including single-cell chromatin accessibility sequencing (scCAS), have enabled profiling the epigenetic landscapes for thousands of individual cells. However, the characteristics of scCAS data, including high dimensionality, high degree of sparsity and high technical variation, make the computational analysis challenging. Reference-guided approaches, which utilize the information in existing datasets, may facilitate the analysis of scCAS data. Here, we present RA3 (Reference-guided Approach for the Analysis of single-cell chromatin Accessibility data), which utilizes the information in massive existing bulk chromatin accessibility and annotated scCAS data. RA3 simultaneously models (1) the shared biological variation among scCAS data and the reference data, and (2) the unique biological variation in scCAS data that identifies distinct subpopulations. We show that RA3 achieves superior performance when used on several scCAS datasets, and on references constructed using various approaches. Altogether, these analyses demonstrate the wide applicability of RA3 in analyzing scCAS data.

scholarly journals Integrative single-cell analysis of transcriptome, DNA methylome and chromatin accessibility in mouse oocytes

Cell Research ◽  
2018 ◽  
Vol 29 (2) ◽  
pp. 110-123 ◽  
Author(s):  
Chan Gu ◽  
Shanling Liu ◽  
Qihong Wu ◽  
Lin Zhang ◽  
Fan Guo
Keyword(s):  
Single Cell ◽  
Single Cell Analysis ◽  
Chromatin Accessibility ◽  
Cell Analysis ◽  
Dna Methylome ◽  
Mouse Oocytes

scholarly journals Single cell multi-omic analysis identifies a Tbx1-dependent multilineage primed population in the murine cardiopharyngeal mesoderm

2020 ◽  
Author(s):  
Hiroko Nomaru ◽  
Yang Liu ◽  
Christopher De Bono ◽  
Dario Righelli ◽  
Andrea Cirino ◽  
...  
Keyword(s):  
Single Cell ◽  
22Q11.2 Deletion Syndrome ◽  
Chromatin Accessibility ◽  
Deletion Syndrome ◽  
22Q11.2 Deletion ◽  
T Box ◽  
Single Cell Rna Sequencing ◽  
Pharyngeal Apparatus ◽  
The Face ◽  
Continuous Source

AbstractThe poles of the heart and branchiomeric muscles of the face and neck are formed from the cardiopharyngeal mesoderm (CPM) within the pharyngeal apparatus. The formation of the cardiac outflow tract and branchiomeric muscles are disrupted in patients with 22q11.2 deletion syndrome (22q11.2DS), due to haploinsufficiency of TBX1, encoding a T-box transcription factor. Here, using single cell RNA-sequencing, we identified a multilineage primed population (MLP) within the CPM, marked by the Tbx1 lineage, which has bipotent properties to form cardiac and skeletal muscle cells. The MLPs are localized within the nascent mesoderm of the caudal lateral pharyngeal apparatus and provide a continuous source of progenitors that undergo TBX1-dependent progression towards maturation. Tbx1 also regulates the balance between MLP maintenance and maturation while restricting ectopic non-mesodermal gene expression. We further show that TBX1 confers this balance by direct regulation of MLP enriched genes and downstream pathways, partly through altering chromatin accessibility. Our study thus uncovers a new cell population and reveals novel mechanisms by which Tbx1 directs the development of the pharyngeal apparatus, which is profoundly altered in 22q11.2DS.

scholarly journals Accessibility Over Transposable Elements Reveals Genetic Determinants of Stemness Properties in Normal and Leukemic Hematopoiesis

2021 ◽  
Author(s):  
Bettina Nadorp ◽  
Giacomo Grillo ◽  
Aditi Qamra ◽  
Amanda Mitchell ◽  
Christopher Arlidge ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Chromatin Accessibility ◽  
Genetic Determinants ◽  
Hematopoietic Stem ◽  
Transcription Regulators ◽  
Docking Sites ◽  
Cellular Hierarchy ◽  
Mutational Processes

AbstractDespite most acute myeloid leukemia (AML) patients achieving complete remission after induction chemotherapy, two thirds of patients will relapse with fatal disease within 5 years. AML is organized as a cellular hierarchy sustained by leukemia stem cells (LSC) at the apex, with LSC properties directly linked to tumor progression, therapy failure and disease relapse 1–5. Despite the central role of LSC in poor patient outcomes, little is known of the genetic determinants of their stemness properties 6–8. Although much AML research focuses on mutational processes and their impact on gene expression programs, the genetic determinants of cell state properties including stemness expand beyond mutations, relying on the genetic architecture captured in the chromatin of each cell 9–11. As LSCs share many functional and molecular properties with normal hematopoietic stem cells (HSC), we identified genetic determinants of primitive populations enriched for LSCs and HSCs in comparison with their downstream mature progeny by investigating their chromatin accessibility. Our work reveals how distinct transposable element (TE) subfamilies are used in primitive versus mature populations, functioning as docking sites for stem cell-associated regulators of genome topology, including CTCF, or lineage-specific transcription regulators in primitive and mature populations, respectively. We further show how TE subfamilies accessible in LSCs define docking sites for several oncogenic drivers in AML, namely FLI1, LYL1 and MEIS1. Using chromatin accessibility profiles from a cohort of AML patients, we further show the clinical utility of our TE accessibility-based LSCTE121 scoring scheme to identify patients with high rates of relapse. Collectively, our work reveals how different accessible TE subfamilies serve as genetic determinants of stemness properties in normal and leukemic hematopoietic stem cells.

scholarly journals Simultaneous trimodal single-cell measurement of transcripts, epitopes, and chromatin accessibility using TEA-seq

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Elliott Swanson ◽  
Cara Lord ◽  
Julian Reading ◽  
Alexander T Heubeck ◽  
Palak C Genge ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Single Cell ◽  
Human Peripheral Blood ◽  
Single Cells ◽  
Cell Types ◽  
Chromatin Accessibility ◽  
Specific Gene ◽  
Test Case ◽  
Cell Assays ◽  
Paired Measurement

Single-cell measurements of cellular characteristics have been instrumental in understanding the heterogeneous pathways that drive differentiation, cellular responses to signals, and human disease. Recent advances have allowed paired capture of protein abundance and transcriptomic state, but a lack of epigenetic information in these assays has left a missing link to gene regulation. Using the heterogeneous mixture of cells in human peripheral blood as a test case, we developed a novel scATAC-seq workflow that increases signal-to-noise and allows paired measurement of cell surface markers and chromatin accessibility: integrated cellular indexing of chromatin landscape and epitopes, called ICICLE-seq. We extended this approach using a droplet-based multiomics platform to develop a trimodal assay that simultaneously measures transcriptomics (scRNA-seq), epitopes, and chromatin accessibility (scATAC-seq) from thousands of single cells, which we term TEA-seq. Together, these multimodal single-cell assays provide a novel toolkit to identify type-specific gene regulation and expression grounded in phenotypically defined cell types.

scholarly journals A Transcriptional Switch Governing Fibroblast Plasticity Underlies Reversibility of Chronic Heart Disease

2020 ◽  
Author(s):  
Michael Alexanian ◽  
Pawel F. Przytycki ◽  
Rudi Micheletti ◽  
Arun Padmanabhan ◽  
Lin Ye ◽  
...  
Keyword(s):  
Heart Disease ◽  
Cardiac Function ◽  
Single Cell ◽  
Cardiac Dysfunction ◽  
Cardiac Fibroblasts ◽  
Regulatory Elements ◽  
Heart Tissue ◽  
Chromatin Accessibility ◽  
Fibroblast Activation ◽  
Transcriptional Switch

AbstractIn diseased organs, stress-activated signaling cascades alter chromatin, triggering broad shifts in transcription and cell state that exacerbate pathology. Fibroblast activation is a common stress response that worsens lung, liver, kidney and heart disease, yet its mechanistic basis remains poorly understood1,2. Pharmacologic inhibition of the BET family of transcriptional coactivators alleviates cardiac dysfunction and associated fibrosis, providing a tool to mechanistically interrogate maladaptive fibroblast states and modulate their plasticity as a potential therapeutic approach3–8. Here, we leverage dynamic single cell transcriptomic and epigenomic interrogation of heart tissue with and without BET inhibition to reveal a reversible transcriptional switch underlying stress-induced fibroblast activation. Transcriptomes of resident cardiac fibroblasts demonstrated robust and rapid toggling between the quiescent fibroblast and activated myofibroblast state in a manner that directly correlated with BET inhibitor exposure and cardiac function. Correlation of single cell chromatin accessibility with cardiac function revealed a novel set of reversibly accessible DNA elements that correlated with disease severity. Among the most dynamic elements was an enhancer regulating the transcription factor MEOX1, which was specifically expressed in activated myofibroblasts, occupied putative regulatory elements of a broad fibrotic gene program, and was required for TGFβ-induced myofibroblast activation. CRISPR interference of the most dynamic cis-element within the enhancer, marked by nascent transcription, prevented TGFβ-induced activation of Meox1. These findings identify MEOX1 as a central regulator of stress-induced myofibroblast activation associated with cardiac dysfunction. The plasticity and specificity of the BET-dependent regulation of MEOX1 in endogenous tissue fibroblasts provides new trans- and cis- targets for treating fibrotic disease.

Non-genetic determinants of malignant clonal fitness at single-cell resolution

Nature ◽  
2021 ◽  
Author(s):  
Katie A. Fennell ◽  
Dane Vassiliadis ◽  
Enid Y. N. Lam ◽  
Luciano G. Martelotto ◽  
Jesse J. Balic ◽  
...  
Keyword(s):  
Single Cell ◽  
Genetic Determinants
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