scholarly journals Single-Cell Multiomics Defines Tolerogenic Extrathymic Aire-Expressing Populations with Unique Homology to Thymic Epithelium

2021 ◽  
Author(s):  
Jiaxi Wang ◽  
Caleb A Lareau ◽  
Jhoanne L Bautista ◽  
Alexander R Gupta ◽  
Katalin Sandor ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Single Cell ◽  
Autoimmune Diabetes ◽  
Antigen Expression ◽  
Cell Types ◽  
Lineage Tracing ◽  
Orphan Receptor ◽  
Thymic Epithelial Cells ◽  
Aire Gene ◽  
Self Tolerance

The Autoimmune Regulator (Aire) gene, well defined for its role in medullary thymic epithelial cells (mTECs) and immune self-tolerance, is also expressed in extrathymic Aire-expressing cells (eTACs) in the secondary lymphoid organs. eTACs have been shown to be hematopoietic antigen presenting cells (APCs) and potent inducers of immune tolerance. However, the precise identity and function of these cells remain unclear. Here, we use high-dimensional single-cell multiomics and functional approaches to define eTACs at the transcriptional, genomic, and proteomic level. We find that eTACs consist of two similar cell types: CCR7+ Aire-expressing migratory dendritic cells (AmDCs) and a unique Aire-hi population co-expressing Aire and RAR-related orphan receptor gamma-t (RORγt). The latter, which have significant transcriptional and genomic homology to migratory dendritic cells (migDCs) and mTECs, we term Janus cells (JCs). All eTACs, and JCs in particular, have a highly accessible chromatin structure and high levels of broad gene expression, including tissue-specific antigens, as well as remarkable transcriptional and genomic homology to thymic medullary epithelium. As in the thymus, Aire expression in eTACs is also dependent on RANK-RANK-ligand interactions. Furthermore, lineage-tracing shows that JCs are not precursors to the majority of AmDCs. Finally, self-antigen expression by eTACs is sufficient to mediate negative selection of T cells escaping thymic selection and can prevent autoimmune diabetes in non-obese diabetic mice. This transcriptional, genomic, and functional symmetry between a hematopoietic Aire-expressing population in the periphery and an epithelial Aire-expressing population in the thymus suggests that a core biological program may influence self-tolerance and self-representation across the spectrum of immune development.

scholarly journals Applications of Single-Cell Omics to Dissect Tumor Microenvironment

2020 ◽  
Vol 11 ◽  
Author(s):  
Tingting Guo ◽  
Weimin Li ◽  
Xuyu Cai
Keyword(s):  
Tumor Microenvironment ◽  
Single Cell ◽  
Immune Cells ◽  
Immune Cell ◽  
Cell Types ◽  
Immune Checkpoint Blockade ◽  
Lineage Tracing ◽  
Great Success ◽  
Novel Technologies ◽  
Single Cell Sequencing

The recent technical and computational advances in single-cell sequencing technologies have significantly broaden our toolkit to study tumor microenvironment (TME) directly from human specimens. The TME is the complex and dynamic ecosystem composed of multiple cell types, including tumor cells, immune cells, stromal cells, endothelial cells, and other non-cellular components such as the extracellular matrix and secreted signaling molecules. The great success on immune checkpoint blockade therapy has highlighted the importance of TME on anti-tumor immunity and has made it a prime target for further immunotherapy strategies. Applications of single-cell transcriptomics on studying TME has yielded unprecedented resolution of the cellular and molecular complexity of the TME, accelerating our understanding of the heterogeneity, plasticity, and complex cross-interaction between different cell types within the TME. In this review, we discuss the recent advances by single-cell sequencing on understanding the diversity of TME and its functional impact on tumor progression and immunotherapy response driven by single-cell sequencing. We primarily focus on the major immune cell types infiltrated in the human TME, including T cells, dendritic cells, and macrophages. We further discuss the limitations of the existing methodologies and the prospects on future studies utilizing single-cell multi-omics technologies. Since immune cells undergo continuous activation and differentiation within the TME in response to various environmental cues, we highlight the importance of integrating multimodal datasets to enable retrospective lineage tracing and epigenetic profiling of the tumor infiltrating immune cells. These novel technologies enable better characterization of the developmental lineages and differentiation states that are critical for the understanding of the underlying mechanisms driving the functional diversity of immune cells within the TME. We envision that with the continued accumulation of single-cell omics datasets, single-cell sequencing will become an indispensable aspect of the immune-oncology experimental toolkit. It will continue to drive the scientific innovations in precision immunotherapy and will be ultimately adopted by routine clinical practice in the foreseeable future.

scholarly journals Transcriptional network analysis of transcriptomic diversity in resident tissue macrophages and dendritic cells in the mouse mononuclear phagocyte system

2020 ◽  
Author(s):  
Kim M. Summers ◽  
Stephen J. Bush ◽  
David A. Hume
Keyword(s):  
Dendritic Cells ◽  
Network Analysis ◽  
Single Cell ◽  
Cell Types ◽  
Mononuclear Phagocyte ◽  
The Body ◽  
Mononuclear Phagocyte System ◽  
Primary Data ◽  
Analysis Tool ◽  
Rna Seq

AbstractThe mononuclear phagocyte system (MPS) is a family of cells including progenitors, circulating blood monocytes, resident tissue macrophages and dendritic cells (DC) present in every tissue in the body. To test the relationships between markers and transcriptomic diversity in the MPS, we collected from NCBI-GEO >500 quality RNA-seq datasets generated from mouse MPS cells isolated from multiple tissues. The primary data were randomly down-sized to a depth of 10 million reads and requantified. The resulting dataset was clustered using the network analysis tool Graphia. A sample-to-sample matrix revealed that MPS populations could be separated based upon tissue of origin. Cells identified as classical DC subsets, cDC1 and cDC2, and lacking Fcgr1 (CD64), were centrally-located within the MPS cluster and no more distinct than other MPS cell types. A gene-to-gene correlation matrix identified large generic co-expression clusters associated with MPS maturation and innate immune function. Smaller co-expression gene clusters including the transcription factors that drive them showed higher expression within defined isolated cells, including macrophages and DC from specific tissues. They include a cluster containing Lyve1 that implies a function in endothelial cell homeostasis, a cluster of transcripts enriched in intestinal macrophages and a generic cDC cluster associated with Ccr7. However, transcripts encoding many other putative MPS subset markers including Adgre1, Itgax, Itgam, Clec9a, Cd163, Mertk, Retnla and H2-a/e (class II MHC) clustered idiosyncratically and were not correlated with underlying functions. The data provide no support for the concept of markers of M2 polarization or the specific adaptation of DC to present antigen to T cells. Co-expression of immediate early genes (e.g. Egr1, Fos, Dusp1) and inflammatory cytokines and chemokines (Tnf, Il1b, Ccl3/4) indicated that all tissue disaggregation protocols activate MPS cells. Tissue-specific expression clusters indicated that all cell isolation procedures also co-purify other unrelated cell types that may interact with MPS cells in vivo. Comparative analysis of public RNA-seq and single cell RNA-seq data from the same lung cell populations showed that the extensive heterogeneity implied by the global cluster analysis may be even greater at a single cell level with few markers strongly correlated with each other. This analysis highlights the power of large datasets to identify the diversity of MPS cellular phenotypes, and the limited predictive value of surface markers to define lineages, functions or subpopulations.

scholarly journals A Single-Cell Atlas and Lineage Analysis of the Adult Drosophila Ovary

2019 ◽  
Author(s):  
Katja Rust ◽  
Lauren Byrnes ◽  
Kevin Shengyang Yu ◽  
Jason S. Park ◽  
Julie B. Sneddon ◽  
...  
Keyword(s):  
Stem Cells ◽  
Single Cell ◽  
Cell Types ◽  
Somatic Tissue ◽  
Lineage Tracing ◽  
Major Cell Type ◽  
Follicle Stem Cells ◽  
Drosophila Ovary ◽  
Adult Drosophila ◽  
Lineage Analysis

AbstractThe Drosophila ovary is a widely used model for germ cell and somatic tissue biology. We have used single-cell RNA-sequencing to build a comprehensive cell atlas of the adult Drosophila ovary containing unique transcriptional profiles for every major cell type in the ovary, including the germline and follicle stem cells. Using this atlas we identify novel tools for identification and manipulation of known and novel cell types and perform lineage tracing to test cellular relationships of previously unknown cell types. By this we discovered a new form of cellular plasticity in which inner germarial sheath cells convert to follicle stem cells in response to starvation.Graphical Abstract

scholarly journals Combined transient ablation and single cell RNA sequencing reveals the development of medullary thymic epithelial cells

2020 ◽  
Author(s):  
Kristen L. Wells ◽  
Corey N. Miller ◽  
Andreas R. Gschwind ◽  
Wu Wei ◽  
Jonah D. Phipps ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Single Cell ◽  
Rna Sequencing ◽  
Expression Patterns ◽  
Critical Role ◽  
Lineage Tracing ◽  
Thymic Epithelial Cells ◽  
Single Cell Rna Sequencing ◽  
Medullary Thymic Epithelial Cells

AbstractMedullary thymic epithelial cells (mTECs) play a critical role in central immune tolerance by mediating negative selection of autoreactive T cells through the collective expression of the peripheral self-antigen compartment, including tissue-specific antigens (TSAs). Recent work has shown that gene expression patterns within the mTEC compartment are remarkably heterogenous and include multiple differentiated cell states. To further define mTEC development and medullary epithelial lineage relationships, we combined lineage tracing and recovery from transient in vivo mTEC ablation with single cell RNA-sequencing. The combination of bioinformatic and experimental approaches revealed a non-stem transit-amplifying population of cycling mTECs that preceded Aire expression. Based on our findings, we propose a branching model of mTEC development wherein a heterogeneous pool of transit-amplifying cells gives rise to Aire- and Ccl21a-expressing mTEC subsets. We further use experimental techniques to show that within the Aire-expressing developmental branch, TSA expression peaked as Aire expression decreased, implying Aire expression must be established before TSA expression can occur. Collectively, these data provide a higher order roadmap of mTEC development and demonstrate the power of combinatorial approaches leveraging both in vivo models and high-dimensional datasets.

scholarly journals Massively parallel single cell lineage tracing using CRISPR/Cas9 induced genetic scars

2017 ◽  
Author(s):  
Bastiaan Spanjaard ◽  
Bo Hu ◽  
Nina Mitic ◽  
Jan Philipp Junker
Keyword(s):  
Single Cell ◽  
Computational Analysis ◽  
Systematic Approach ◽  
Single Cells ◽  
Cell Lineage ◽  
Transcriptome Profiling ◽  
Cell Types ◽  
Lineage Tracing ◽  
Lineage Trees ◽  
Different Cell Types

A key goal of developmental biology is to understand how a single cell transforms into a full-grown organism consisting of many different cell types. Single-cell RNA-sequencing (scRNA-seq) has become a widely-used method due to its ability to identify all cell types in a tissue or organ in a systematic manner 1–3. However, a major challenge is to organize the resulting taxonomy of cell types into lineage trees revealing the developmental origin of cells. Here, we present a strategy for simultaneous lineage tracing and transcriptome profiling in thousands of single cells. By combining scRNA-seq with computational analysis of lineage barcodes generated by genome editing of transgenic reporter genes, we reconstruct developmental lineage trees in zebrafish larvae and adult fish. In future analyses, LINNAEUS (LINeage tracing by Nuclease-Activated Editing of Ubiquitous Sequences) can be used as a systematic approach for identifying the lineage origin of novel cell types, or of known cell types under different conditions.

Integrative analysis of scRNAs-seq and scATAC-seq revealed transit-amplifying thymic epithelial cells expressing autoimmune regulator

2021 ◽  
Author(s):  
Takahisa Miyao ◽  
Maki Miyauchi ◽  
S. Thomas Kelly ◽  
Tommy W. Terooatea ◽  
Tatsuya Ishikawa ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Single Cell ◽  
Tolerance Induction ◽  
Integrative Analysis ◽  
Thymic Epithelial Cells ◽  
Self Tolerance ◽  
Cell Assays ◽  
Medullary Thymic Epithelial Cells ◽  
Specific Antigens ◽  
Accessible Chromatin

SummaryMedullary thymic epithelial cells (mTECs) are critical for self-tolerance induction in T cells via promiscuous expression of tissue-specific antigens (TSAs), which are controlled by transcriptional regulator AIRE. Whereas AIRE-expressing (Aire+) mTECs undergo constant turnover in the adult thymus, mechanisms underlying differentiation of postnatal mTECs remain to be discovered. Integrative analysis of single-cell assays for transposase accessible chromatin (scATAC-seq) and single-cell RNA sequencing (scRNA-seq) suggested the presence of proliferating mTECs with a specific chromatin structure, which express high levels of Aire and co-stimulatory molecules CD80 (Aire+CD80hi). Proliferating Aire+CD80hi mTECs detected by using Fucci technology express a minimal level of Aire-dependent TSAs and are converted into quiescent Aire+CD80hi mTECs expressing high levels of TSAs after a transit amplification. These data provide evidence for the existence of transit amplifying Aire+mTEC precursors during Aire+mTEC differentiation process of the postnatal thymus.

scholarly journals Lineage tracing on transcriptional landscapes links state to fate during differentiation

2018 ◽  
Author(s):  
Caleb Weinreb ◽  
Alejo Rodriguez-Fraticelli ◽  
Fernando Camargo ◽  
Allon M Klein
Keyword(s):  
Single Cell ◽  
Cell Biology ◽  
Cell Types ◽  
Lineage Tracing ◽  
Cell Potential ◽  
Monocyte Differentiation ◽  
Cell Assays ◽  
Transcriptional Landscape ◽  
Developmental Hierarchy

AbstractA challenge in stem cell biology is to associate molecular differences among progenitor cells with their capacity to generate mature cell types. Though the development of single cell assays allows for the capture of progenitor cell states in great detail, these assays cannot definitively link cell states to their long-term fate. Here, we use expressed DNA barcodes to clonally trace single cell transcriptomes dynamically during differentiation and apply this approach to the study of hematopoiesis. Our analysis identifies functional boundaries of cell potential early in the hematopoietic hierarchy and locates them on a continuous transcriptional landscape. We reconstruct a developmental hierarchy showing separate ontogenies for granulocytic subtypes and two routes to monocyte differentiation that leave a persistent imprint on mature cells. Finally, we use our approach to benchmark methods of dynamic inference from single-cell snapshots, and provide evidence of strong early fate biases dependent on cellular properties hidden from single-cell RNA sequencing.

scholarly journals The transcriptional landscape of mTEChi and mTEClo.

2020 ◽  
Author(s):  
Shahan Mamoor
Keyword(s):  
Transcriptional Profiling ◽  
Cell Subset ◽  
Cell Types ◽  
Thymic Epithelial Cells ◽  
Surface Receptors ◽  
Mhc Ii ◽  
Histocompatibility Complex ◽  
Self Tolerance ◽  
Medullary Thymic Epithelial Cells ◽  
Differential Gene

Medullary thymic epithelial cells, or mTEC, are cells of the thymus that can be sorted and classified based on expression of the class II major histocompatibility complex, MHC-II (1-3). mTEChi and mTEClo can be further segregated by expression of the CD80 marker, but there are few systematic analyses of the unique transcriptional behavior of each mTEC cell subset (4-6). We performed global differential gene expression profiling by comparing the transcriptomes of mTEChi and mTEClo (7) to determine the most significant transcriptional differences between these two cell subsets of the thymus. We found nearly a dozen groups of gene that distinctly identify these two cell types from each other. These included phospholipase-type enzymes, transcription factors, transcriptional coactivators and epigenetic proteins, cell signaling intermediates, cell surface receptors, molecules involved in ubiquitination, taste receptors, cathepsins, and interleukin-13. mTEChi and mTEClo can be discerned with facility as discrete cell types independent of MHC-II and CD80 expression through systematic comparative transcriptional profiling and the molecular descriptions provided here can be used as a resource for future investigations into the organ primarily responsible for providing lymphocyte self-tolerance instruction.

EPCO-26. INTEGRATIVE MULTI-OMICS IDENTIFIES CONVERGING DEVELOPMENTAL ORIGINS OF DISTINCT MEDULLOBLASTOMA SUBGROUPS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi7-vi7
Author(s):  
Kyle Smith ◽  
Laure Bihannic ◽  
Brian Gudenas ◽  
Qingsong Gao ◽  
Parthiv Haldipur ◽  
...  
Keyword(s):  
Single Cell ◽  
Developmental Trajectories ◽  
Cell Lineage ◽  
Cell Types ◽  
Lineage Tracing ◽  
Group 4 ◽  
Group 3 ◽  
Mechanistic Basis ◽  
Rhombic Lip

Abstract Understanding the interplay between normal development and tumorigenesis, including the identification and characterization of lineage-specific origins of MB, is a fundamental challenge in the field. Recent studies have highlighted novel associations between biologically distinct MB subgroups and diverse murine cerebellar lineages via cross-species single-cell transcriptomics. Specifically, Group 4-MB correlated with the unipolar brush cell lineage and Group 3-MB resembled Nestin+ stem cells of the early cerebellum. However, these analyses were hampered by low resolution due to the sparsity of pertinent cerebellar cell types and the cross-species nature of the approach. Herein, we profoundly expand the depth of these rare developmental populations in the murine cerebellum using a combination of lineage tracing and integrative multi-omics. Isolation and enrichment of spatially and temporally unique developmental trajectories of key rhombic lip-derived glutamatergic lineages provided an enhanced reference for mapping MB subgroups based on molecular overlap, especially for poorly defined Group 3- and Group 4-MB. Further comparisons to a novel single-cell atlas of the human fetal cerebellum, companioned with laser-capture microdissected transcriptional and epigenetic datasets, reinforced developmental insights extracted from the mouse. Characterization of compartment-specific transcriptional programs and co-expression networks identified in the human upper rhombic lip implicated convergent cellular correlates of Group 3- and Group 4-MB, suggestive of a common developmental link. Together, our results strongly implicate developmental lineages of the upper rhombic lip as the probable origins of poorly defined Group 3- and Group 4-MB. These important findings will shape future efforts to accurately model the biological heterogeneity underlying these subgroups and provide unprecedented opportunities to explore their cellular and mechanistic basis.

scholarly journals Aire-dependent production of XCL1 mediates medullary accumulation of thymic dendritic cells and contributes to regulatory T cell development

2011 ◽  
Vol 208 (2) ◽  
pp. 383-394 ◽  
Author(s):  
Yu Lei ◽  
Adiratna Mat Ripen ◽  
Naozumi Ishimaru ◽  
Izumi Ohigashi ◽  
Takashi Nagasawa ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Chemokine Receptor ◽  
T Cell Development ◽  
Cell Development ◽  
Thymic Epithelial Cells ◽  
Naturally Occurring ◽  
Self Tolerance ◽  
Medullary Thymic Epithelial Cells ◽  
Deficient Mice

Dendritic cells (DCs) in the thymus (tDCs) are predominantly accumulated in the medulla and contribute to the establishment of self-tolerance. However, how the medullary accumulation of tDCs is regulated and involved in self-tolerance is unclear. We show that the chemokine receptor XCR1 is expressed by tDCs, whereas medullary thymic epithelial cells (mTECs) express the ligand XCL1. XCL1-deficient mice are defective in the medullary accumulation of tDCs and the thymic generation of naturally occurring regulatory T cells (nT reg cells). Thymocytes from XCL1-deficient mice elicit dacryoadenitis in nude mice. mTEC expression of XCL1, tDC medullary accumulation, and nT reg cell generation are diminished in Aire-deficient mice. These results indicate that the XCL1-mediated medullary accumulation of tDCs contributes to nT reg cell development and is regulated by Aire.

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