An integrated approach to profile lung tumor endothelial cell heterogeneity across species and models and to identify angiogenic candidates
ABSTRACT: Heterogeneity of lung tumor endothelial cell (TEC) phenotypes across patients, species (human/mouse) and models (in vivo/vitro) remains poorly inventoried at the single-cell-level. We single-cell RNA-sequenced 56,771 ECs from human/mouse (peri)-tumoral lung and cultured human lung TECs, detected 17 known and discovered 16 novel phenotypes, including TECs presumably regulating immune surveillance. We resolved the canonical tip TECs into a known migratory tip and a novel basement-membrane remodeling breach phenotype. Tip-TEC signatures correlated with patient-survival, and tip/breach TECs were most sensitive to VEGF-blockade. By similarity analysis, only tip-TECs were congruent across species/models and shared conserved markers. Integrated analysis of the scRNA-seq data with orthogonal multi-omics and meta-analysis data across different human tumors, validated by functional analysis, identified collagen-modification as angiogenic candidate pathway.
Project description:T cell differentiation is governed by interactions with thymic epithelial cells (TECs) and defects in this process undermine immune function and tolerance. To uncover new strategies to restore thymic function and adaptive immunity in immunodeficiency, we sought to determine the molecular mechanisms that control life and death decisions in TEC. We created a mouse model which specifically deleted the pro-survival gene Mcl1 in TEC. We found that while BCL-2 and BCL-XL were dispensable for TEC homeostasis, MCL-1 deficiency impacted on TEC as early as E15.5, resulting in early thymic atrophy and T cell lymphopenia, with near complete loss of thymic tissue by 2 months of age. MCL-1 was not necessary for TEC differentiation but was continually required for the survival of medullary TEC, including autoimmune regulator (AIRE) expressing TECs and the maintenance of overall thymic architecture. To understand the molecular mechanisms in more detail, RNA-seq profiling was undertaken of cortical and medullary thymic epithelial cells (cTECs and mTECs) from wildtype and knockout mice. Overall design: The number of biological replicates was n=4 for WT cTECs, n=2 for WT mTECs, n=1 for KO cTECs and n=1 for KO mTECs.
Project description:The heterogeneity of endothelial cells (ECs), lining blood vessels, across tissues remains incompletely inventoried. We constructed an atlas of >32,000 single-EC transcriptomic data from 11 tissues of the model organism Mus musculus. We propose a new classification of EC phenotypes based on transcriptome signatures and inferred putative biological features. We identified top-ranking markers for ECs from each tissue. ECs from different vascular beds (arteries, capillaries, veins, lymphatics) resembled each other across tissues, but only arterial, venous and lymphatic (not capillary) ECs shared markers, illustrating a greater heterogeneity of capillary ECs. We identified high-endothelial-venule and lacteal-like ECs in the intestines, and angiogenic ECs in healthy tissues. Metabolic transcriptomes of ECs differed amongst spleen, lung, liver, brain and testis, while being similar for kidney, heart, muscle and intestines. Within tissues, metabolic gene expression was heterogeneous amongst ECs from different vascular beds, altogether highlighting large EC heterogeneity.
Project description:Thymic epithelial cells (TECs) support T cell development in the thymus. Cortical thymic epithelial cells (cTECs) facilitate positive selection of developing thymocytes whereas medullary thymic epithelial cells (mTECs) facilitate the deletion of self-reactive thymocytes in order to prevent autoimmunity. The mTEC compartment is highly dynamic with continuous maturation and turnover, but the genetic regulation of these processes remains poorly understood. MicroRNAs (miRNAs) are important regulators of TEC genetic programs since miRNA-deficient TECs are severely defective. However, the individual miRNAs important for TEC maintenance and function and their mechanisms of action remain unknown. Here, we demonstrate that miR-205 is highly and preferentially expressed in mTECs during both thymic ontogeny and in the postnatal thymus. This distinct expression is suggestive of functional importance for TEC biology. Genetic ablation of miR-205 in TECs, however, neither revealed a role for miR-205 in TEC function during homeostatic conditions nor during recovery from thymic stress conditions. Thus, despite its distinct expression, miR-205 on its own is largely dispensable for mTEC biology. In order to identify miRNAs differentially expressed in mTECs, we purified cortical thymic epithelial cells (cTECs), mTECs and CD45+ cells as three distinct populations and prepared RNA for microarray analysis. Thymic subsets were FACS-purified from 4-week old NOD wildtype mice. Thymi from 10-12 female mice were pooled together for stromal cell isolation for a total of 3 CD45+, 2 cTEC and 3 mTEC biologic replicates.
Project description:Purpose: In all vertebrates, the thymus is necessary and sufficient for production of classic adaptive T cells. The key components of the thymus are cortical and medullary thymic epithelial cells (cTECs and mTECs). Despite the capital role of TECs, our understanding of TEC biology is quite rudimentary. For instance, we ignore what might be the extent of divergence in the functional program of these two TECs populations. It also remains unclear why the number of TECs decreases rapidly with age, thereby leading to progressive thymic insufficiency. Methods: Systems level understanding of cell function begins with gene expression profiling, and the transcriptome is currently the only '-ome' that can be reliably tackled in its entirety in freshly harvested primary cells. In order to gain novel insights into TEC biology, we therefore decided to analyse the whole transcriptome of cTECs, mTECs and skin epithelial cells. We elected to analyse gene expression using RNA-seq rather microarrays because RNA-seq has higher sensitivity and dynamic range coupled to lower technical variations. Results: Our deep sequencing approach provides a unique perspective into the transcriptome of TECs. Consistent with their ability to express ectopic genes, we found that mTECs expressed more genes than other cell populations. Out of a total of 15,069 genes expressed in TECs, 25% were differentially expressed by at least 5-fold in cTECs vs. mTECs. Genes expressed at higher levels in cTECs than mTECs regulate numerous cell functions including cell differentiation, cell movement and microtubule dynamics. Almost all positive regulators of the cell cycle were overexpressed in skin ECs relative to TECs. Conclusions: Our RNA-seq data provide novel insights into the transcriptional landscape of TECs, highlight substantial divergences in the transcriptome of TEC subsets and suggest that cell cycle progression is differentially regulated in TECS and skinECs. We believe that our work will therefore represent a valuable resource and will be of great interest to readers working in biological sciences, particularly in the areas of immunology and systems biology. The mRNA profiles of cTEC, mTEC (from 14 thymi of 7-days old C57BL/6 mice) and skinEC (from the trunk and dorsum of seven newborn mice) were generated by RNA-sequencing using Illumina HiSeq2000.
Project description:To more specifically determine whether the TEC program is controlled by Notch, we generated molecular definitions of TECs and MPCs by whole transcriptome sequencing of sorted KLRG1-CD127+ and KLRG1+CD127- H-2 Db-NP specific CD8+ T cell populations from wild-type mice. These definitions were used to analyze data derived from RNAseq of splenic H-2 Db-NP+CD8+ T cells from WT and Notch1-2-KO mice 10 days post-infection with A/HKx31.
Project description:Genetic modeling of thymic involution has demonstrated the importance of individual inflammatory pathways affecting the thymic microenvironment, particularly thymic epithelial cells (TEC). We studied the pathogenic processes in chronological aging of the murine thymus. We used microarrays to elucidate the global gene expression and to identify a leading edge subset of age-associated genes in TEC. Analyses of the TEC transcriptome demonstrated altered expression associated with inflammatory and fatty acid metabolism. Overall design: TECs were FACS sorted from different age of mice (6 weeks, 7 months and 15 months old) for RNA extraction and hybridization on Affymetrix microarrays. Each cohort sample derived from 3-5 mice.
Project description:This study aims at isolate a subpopulation of thymic epithelial cells (TECs) enrich in thymic epithelial progenitors. While recent studies have shown that bipotent TEC progenitors exist in adults, the identity of thymic epithelial progenitors (TEPCs) is still debated. Using an exclusively in vivo approach, we show that quiescent UEA1– TECs actively proliferate during thymic regeneration in 6-month-old mice and possessed a MHCIIlo Sca1hi CD49fhi CD24lo Plet1– phenotype. We then performed RNA sequencing of UEA1- quiescent (label-retaining cells, called LRCs) cells and compared them to UEA1- GFP- (nonquiescent, NonLRCs) TECs. Overall design: We analyzed 2 samples with one replicate each. Each sample contains pooled cells isolated from 11 mice to reach a minimum of 10000 cells/replicate.