scholarly journals Combinatorial action of transcription factors in open chromatin contributes to early cellular heterogeneity and organizer mesendoderm specification

2020 ◽  
Author(s):  
Ann Rose Bright ◽  
Siebe van Genesen ◽  
Qingqing Li ◽  
Simon J. van Heeringen ◽  
Alexia Grasso ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Single Cell ◽  
Marginal Zone ◽  
Chromatin Accessibility ◽  
Cellular Heterogeneity ◽  
Open Chromatin ◽  
Cell Clusters ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

ABSTRACTDuring gastrulation, mesoderm is induced in pluripotent cells, concomitant with dorsal-ventral patterning and establishing of the dorsal axis. How transcription factors operate within the constraints of chromatin accessibility to mediate these processes is not well-understood. We applied chromatin accessibility and single cell transcriptome analyses to explore the emergence of heterogeneity and underlying gene-regulatory mechanisms during early gastrulation in Xenopus. ATAC-sequencing of pluripotent animal cap cells revealed a state of open chromatin of transcriptionally inactive lineage-restricted genes, whereas chromatin accessibility in dorsal marginal zone cells more closely reflected the transcriptional activity of genes. We characterized single cell trajectories in animal cap and dorsal marginal zone in early gastrula embryos, and inferred the activity of transcription factors in single cell clusters by integrating chromatin accessibility and single cell RNA-sequencing. We tested the activity of organizer-expressed transcription factors in mesoderm-competent animal cap cells and found combinatorial effects of these factors on organizer gene expression. In particular the combination of Foxb1 and Eomes induced a gene expression profile that mimicked those observed in head and trunk organizer single cell clusters. In addition, genes induced by Eomes, Otx2 or the Irx3-Otx2 combination, were enriched for promoters with maternally regulated H3K4me3 modifications, whereas promoters selectively induced by Lhx8 were marked more frequently by zygotically controlled H3K4me3. Our results show that combinatorial activity of zygotically expressed transcription factors acts on maternally-regulated accessible chromatin to induce organizer gene expression.

scholarly journals Deciphering intratumoral heterogeneity using integrated clonal tracking and single-cell transcriptome analyses

2021 ◽  
Author(s):  
Rong Lu ◽  
HUMBERTO CONTRERAS-TRUJILLO ◽  
JIYA EERDENG ◽  
SAMIR AKRE ◽  
DU JIANG ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Dna Barcode ◽  
Treatment Resistance ◽  
Intratumoral Heterogeneity ◽  
Integrated System ◽  
Cellular Heterogeneity ◽  
Gene Expression Signatures ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

Abstract Cellular heterogeneity is a major cause of treatment resistance in cancer. Despite recent advances in single-cell genomic and transcriptomic sequencing, it remains difficult to relate measured molecular profiles to the cellular activities underlying cancer. Here, we present an integrated experimental system that connects single cell gene expression to heterogeneous cancer cell growth, metastasis, and treatment response. Our system integrates single cell transcriptome profiling with DNA barcode based clonal tracking in patient-derived xenograft models. We show that leukemia cells exhibiting unique gene expression signatures respond to different chemotherapies in distinct but consistent manners across multiple mice. In addition, we uncover an unexpected yet common form of leukemia expansion that is spatially confined to the bone marrow of single anatomical sites and driven by cells with distinct gene expression signatures. Our integrated system directly and effectively interrogates the molecular and cellular basis of the intratumoral heterogeneity underlying disease progression and treatment resistance.

scholarly journals Deciphering intratumoral heterogeneity using integrated clonal tracking and single-cell transcriptome analyses

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Humberto Contreras-Trujillo ◽  
Jiya Eerdeng ◽  
Samir Akre ◽  
Du Jiang ◽  
Jorge Contreras ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Dna Barcode ◽  
Treatment Resistance ◽  
Experimental System ◽  
Transcriptome Profiling ◽  
Intratumoral Heterogeneity ◽  
Cellular Heterogeneity ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

AbstractCellular heterogeneity is a major cause of treatment resistance in cancer. Despite recent advances in single-cell genomic and transcriptomic sequencing, it remains difficult to relate measured molecular profiles to the cellular activities underlying cancer. Here, we present an integrated experimental system that connects single cell gene expression to heterogeneous cancer cell growth, metastasis, and treatment response. Our system integrates single cell transcriptome profiling with DNA barcode based clonal tracking in patient-derived xenograft models. We show that leukemia cells exhibiting unique gene expression respond to different chemotherapies in distinct but consistent manners across multiple mice. In addition, we uncover a form of leukemia expansion that is spatially confined to the bone marrow of single anatomical sites and driven by cells with distinct gene expression. Our integrated experimental system can interrogate the molecular and cellular basis of the intratumoral heterogeneity underlying disease progression and treatment resistance.

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 Diversification of reprogramming trajectories revealed by parallel single-cell transcriptome and chromatin accessibility sequencing

2020 ◽  
Vol 6 (37) ◽  
pp. eaba1190
Author(s):  
Q. R. Xing ◽  
C. A. El Farran ◽  
P. Gautam ◽  
Y. S. Chuah ◽  
T. Warrier ◽  
...  
Keyword(s):  
Single Cell ◽  
Chromatin Accessibility ◽  
Human Cells ◽  
Cellular Reprogramming ◽  
Surface Markers ◽  
Low Efficiency ◽  
Cell Transcriptome ◽  
Intermediate Cells ◽  
Single Cell Transcriptome ◽  
Accessible Chromatin

Cellular reprogramming suffers from low efficiency especially for the human cells. To deconstruct the heterogeneity and unravel the mechanisms for successful reprogramming, we adopted single-cell RNA sequencing (scRNA-Seq) and single-cell assay for transposase-accessible chromatin (scATAC-Seq) to profile reprogramming cells across various time points. Our analysis revealed that reprogramming cells proceed in an asynchronous trajectory and diversify into heterogeneous subpopulations. We identified fluorescent probes and surface markers to enrich for the early reprogrammed human cells. Furthermore, combinatory usage of the surface markers enabled the fine segregation of the early-intermediate cells with diverse reprogramming propensities. scATAC-Seq analysis further uncovered the genomic partitions and transcription factors responsible for the regulatory phasing of reprogramming process. Binary choice between a FOSL1 and a TEAD4-centric regulatory network determines the outcome of a successful reprogramming. Together, our study illuminates the multitude of diverse routes transversed by individual reprogramming cells and presents an integrative roadmap for identifying the mechanistic part list of the reprogramming machinery.

scholarly journals Mesenchymal Stromal Cells in the Bone Marrow Niche Consist of Multi-Populations With Distinct Transcriptional and Epigenetic Properties

2021 ◽  
Author(s):  
Sanshiro Kanazawa ◽  
Hironori Hojo ◽  
Shinsuke Ohba ◽  
Junichi Iwata ◽  
Makoto Komura ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Single Cell ◽  
Expression Profiles ◽  
Marker Genes ◽  
Mouse Bone Marrow ◽  
Bone Marrow Niche ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

Abstract Although multiple studies have investigated the mesenchymal stem and progenitor cells (MSCs) that give rise to mature bone marrow, high heterogeneity in their morphologies and properties causes difficulties in molecular separation of their distinct populations. In this study, by taking advantage of the resolution of the single cell transcriptome, we analyzed Sca-1 and PDGFR-α fraction in the mouse bone marrow tissue. The single cell transcriptome enabled us to further classify the population into seven populations according to their gene expression profiles. We then separately obtained the seven populations based on candidate marker genes, and specified their gene expression properties and epigenetic landscape by ATAC-seq. Our findings will enable to elucidate the stem cell niche signal in the bone marrow microenvironment, reconstitute bone marrow in vitro, and shed light on the potentially important role of identified subpopulation in various clinical applications to the treatment of bone- and bone marrow-related diseases.

scholarly journals A Single-Cell Transcriptome Atlas for Zebrafish Development

2019 ◽  
Author(s):  
Dylan R. Farnsworth ◽  
Lauren Saunders ◽  
Adam C. Miller
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Cell Types ◽  
Developmental Time ◽  
Cell Type ◽  
Specific Expression ◽  
Transcriptional Profiles ◽  
Larval Stages ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

ABSTRACTThe ability to define cell types and how they change during organogenesis is central to our understanding of animal development and human disease. Despite the crucial nature of this knowledge, we have yet to fully characterize all distinct cell types and the gene expression differences that generate cell types during development. To address this knowledge gap, we produced an Atlas using single-cell RNA-sequencing methods to investigate gene expression from the pharyngula to early larval stages in developing zebrafish. Our single-cell transcriptome Atlas encompasses transcriptional profiles from 44,102 cells across four days of development using duplicate experiments that confirmed high reproducibility. We annotated 220 identified clusters and highlighted several strategies for interrogating changes in gene expression associated with the development of zebrafish embryos at single-cell resolution. Furthermore, we highlight the power of this analysis to assign new cell-type or developmental stage-specific expression information to many genes, including those that are currently known only by sequence and/or that lack expression information altogether. The resulting Atlas is a resource of biologists to generate hypotheses for genetic (mutant) or functional analysis, to launch an effort to define the diversity of cell-types during zebrafish organogenesis, and to examine the transcriptional profiles that produce each cell type over developmental time.

scholarly journals Lifelong single-cell profiling of cranial neural crest diversification

2021 ◽  
Author(s):  
Peter Fabian ◽  
Kuo-Chang Tseng ◽  
Mathi Thiruppathy ◽  
Claire Arata ◽  
Hung-Jhen Chen ◽  
...  
Keyword(s):  
Neural Crest ◽  
Single Cell ◽  
Cell Fate ◽  
Intrinsic Property ◽  
Chromatin Accessibility ◽  
Specific Cell ◽  
List Type ◽  
Cranial Neural Crest ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

AbstractThe cranial neural crest generates a huge diversity of derivatives, including the bulk of connective and skeletal tissues of the vertebrate head. How neural crest cells acquire such extraordinary lineage potential remains unresolved. By integrating single-cell transcriptome and chromatin accessibility profiles of cranial neural crest-derived cells across the zebrafish lifetime, we observe region-specific establishment of enhancer accessibility for distinct fates. Neural crest-derived cells rapidly diversify into specialized progenitors, including multipotent skeletal progenitors, stromal cells with a regenerative signature, fibroblasts with a unique metabolic signature linked to skeletal integrity, and gill-specific progenitors generating cell types for respiration. By retrogradely mapping the emergence of lineage-specific chromatin accessibility, we identify a wealth of candidate lineage-priming factors, including a Gata3 regulatory circuit for respiratory cell fates. Rather than multilineage potential being an intrinsic property of cranial neural crest, our findings support progressive and region-specific chromatin remodeling underlying acquisition of diverse neural crest lineage potential.HighlightsSingle-cell transcriptome and chromatin atlas of cranial neural crestProgressive emergence of region-specific cell fate competencyChromatin accessibility mapping identifies candidate lineage regulatorsGata3 function linked to gill-specific respiratory programGraphical Abstract

scholarly journals scAAVengr: Single-cell transcriptome-based quantification of engineered AAVs in non-human primate retina

2020 ◽  
Author(s):  
Bilge E. Öztürk ◽  
Molly E. Johnson ◽  
Michael Kleyman ◽  
Serhan Turunç ◽  
Jing He ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Cell Types ◽  
Adeno Associated Virus ◽  
Gene Therapies ◽  
Naturally Occurring ◽  
Cell Transcriptome ◽  
Large Animals ◽  
Single Cell Transcriptome ◽  
Human Primate

AbstractAdeno-associated virus (AAV)-mediated gene therapies are rapidly advancing to the clinic, and AAV engineering has resulted in vectors with increased ability to deliver therapeutic genes. Although the choice of vector is critical, quantitative comparison of AAVs, especially in large animals, remains challenging. Here, we developed an efficient single-cell AAV engineering pipeline (scAAVengr) to quantify efficiency of AAV-mediated gene expression across all cell types. scAAVengr allows for definitive, head-to-head comparison of vectors in the same animal. To demonstrate proof-of-concept for the scAAVengr workflow, we quantified – with cell-type resolution – the abilities of naturally occurring and newly engineered AAVs to mediate gene expression in primate retina following intravitreal injection. A top performing variant, K912, was used to deliver SaCas9 and edit the rhodopsin gene in macaque retina, resulting in editing efficiency similar to infection rates detected by the scAAVengr workflow. These results validate scAAVengr as a powerful method for development of AAV vectors.

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