Developmental dynamics of the neural crest-mesenchymal axis in creating the thymic microenvironment
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PROVIDER: PRJNA770355 | ENA |
REPOSITORIES: ENA
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Project description:The thymic stroma is composed of epithelial and non-epithelial cells that collectively provide separate microenvironment controlling the homing of blood-born precursors to the tissue, and their subsequent differentiation to functionally mature and correctly selected T cells. While thymic epithelial cells are well characterised for their role in thymopoiesis, a comparably comprehensive analysis of the non-epithelial thymic stroma is lacking. Here we explore at single cell resolution the complex composition and dynamic changes that occur over time in the non-epithelial stromal compartmenti. We detail across different developmental stages in human and mouse thymus tissues and in an experimental model of the most common form of human thymus hypoplasia the separate transcriptomes of mouse mesothelium, fibroblasts, neural crest cells, endothelial and vascular mural cells. The detected gene expression signatures identify novel stromal subtypes and relate their individual molecular profiles to separate differentiation trajectories and functions. Specifically, we demonstrate an abundance and unprecedented heterogeneity of diverse fibroblast subtypes that emerge at discrete developmental stages and vary in their expression of key regulatory signalling circuits and components of the extracellular matrix. Taken together, these findings highlight the dynamic complexity of the non-epithelial thymus stroma and link the cells’ specific gene expression profiles to separate instructive roles essential for normal thymus organogenesis and tissue maintenance. The study has been granted ethical approval and is publicly listed (IRAS ID 156910, CPMS 19587).
2022-05-13 | GSE185669 | GEO
Project description:The thymus is one of the most affected organs during malnutrition, exhibiting atrophy and thymocyte depletion, characteristics that are also observed in several infectious diseases. The detrimental effects of malnutrition on immune responses to pathogens have long been recognized and it is considered a main risk factor for various infectious diseases, including visceral leishmaniasis (VL). However, the thymus has been barely studied during malnutrition and Leishmania infantum infection association. Protein malnutrition modifies intrathymic communication in L. infantum infected BALB/c mice by altering the abundance of proteins secreted to the thymic interstitial fluid (IF). We identified and compared protein abundance in the thymic IF samples from BALB/c mice that were fed with control protein (14%, CP) or low protein (4%, LP) isocaloric diets, followed by infection with L. infantum. By means of a quantitative proteomics approach using iTRAQ we identified 280 proteins of which 81% were reported as secreted by exosomes and 42% were previously described as secreted by thymic epithelial cells. LP-infected (LPi) animals showed a significant decrease in exosomal proteins, suggesting that exosomal carrier system is dysregulated in malnourished animals. LPi mice also exhibited an increase in the relative abundance of proteins involved in lipid metabolism and tricarboxylic acid cycle, suggestive of a non-proliferative microenvironment. Accordingly, flow cytometry analysis revealed that protein malnutrition decreases the proliferation of single positive and double positive T cells. Proteins engaged in glycolysis, protein ubiquitination and mRNA processing were significantly decreased. In addition, a significant decrease in the abundance of galectin-1 and increase of plasminogen were observed in malnourished animals. Together, the reduced cortical area, decreased proliferation, increased abundance of lipid- and tricarboxylic acid cycle-related proteins, and altered abundance of galectin-1 and plasminogen indicate a dysfunctional thymic microenvironment, where T cell migration, proliferation and maturation are compromised, contributing for the thymic atrophy observed in malnourished animals. All these alterations affect the control of the local and systemic infection, resulting in an impaired response to L. infantum infection.
2019-11-12 | PXD010414 | Pride
Project description:cDCs home from the periphery into the thymus. In order to determine the phenotypic and functional changes introduced by the thymic microenvironment to these thymus-homing cDCs, RNA-based next generation sequencing (RNAseq) was performed with splenic (sp-DC) and thymic conventional DCs (t-DCs) re-isolated from RTOCs after two days of culture. Methods: RTOCs were generated from single-cell suspensions of thymi isolated from E14.5 to E16.5 fetuses of Foxp3hCD2 reporter mice (BALB/c background), and sp‑DCs or t‑DCs sorted from 4-8 weeks old female CD45.1xBALB/c mice were introduced. After two days of culture, 1‑2x103 cDCs were re-isolated from RTOCs as CD45.1+Lin-CD11chi by FACS, and total RNA for transcriptional profiling by low-input RNAseq was isolated. Total RNA from sp-DC and t-DCs isolated ex vivo from 4-8 weeks old female CD45.1xBALB/c mice was used as control. RNAseq was performed on an Illumina HiSeq2500 system. Differential gene expression between the four different conditions was computed from the read counts. Results: The number of differentially expressed genes between ex vivo isolated sp-DC and t-DC was drastically reduced comparing sp-DCs and t-DCs re-isolated from RTOCs. This finding implies that the thymic microenvironment within an RTOC modulates the gene expression in sp‑DCs, conferring a transcriptomic profile that more closely resembled the one from t‑DCs. Conclusion: The thymic microenvironment modulates the transcriptome of thymus-homing peripheral cDCs.
2021-03-01 | GSE164280 | GEO
Project description:T cell development in the thymus is essential for cellular immunity and depends on the organotypic thymic epithelial microenvironment. Compared to other organs, the size and cellular composition of the thymus is unusually dynamic, exemplified by rapid growth and high T cell output during early stages of development, followed by a gradual loss of functional thymic epithelial cells and diminished naïve T cell production with age. Single-cell RNA sequencing (scRNA-seq) has uncovered an unexpected heterogeneity of cell types in the thymic epithelium of young and aged adult mice; however, the identities and developmental dynamics of putative pre- and postnatal epithelial progenitors have remained unresolved. Here, we combine scRNA-seq and a novel CRISPR/Cas9-based cellular barcoding system in mice to determine qualitative and quantitative changes in the thymic epithelium over time. This dual approach enabled us to identify two principal progenitor populations: an early bi-potent progenitor type biased towards cortical epithelium, and a postnatal bi-potent progenitor population biased towards medullary epithelium. We further demonstrate that continuous autocrine provision of Fgf7 leads to sustained expansion of thymic microenvironments without exhausting the epithelial progenitor pools, suggesting a strategy to modulate the extent of thymopoietic activity.
2022-03-30 | GSE106856 | GEO
Project description:The thymic microenvironment is essential for proper differentiation and selection of thymocytes.Thymic involution in aged mice results in decreased T cell output and immune function. Here we use gene expression profiling of FACS sorted thymic stromal subsets to identify molecular mediators of thymocyte: stromal cell interactions, as well as gene expression changes thymic stromal subsets during early stages of thymic involution . We used microarrays to analyze gene expression differences between thymic stromal subsets from male C57BL/6J mice 1, 3, and 6 months of age.
2014-09-12 | GSE56928 | GEO
Project description:The thymic microenvironment is essential for proper differentiation and selection of thymocytes.Thymic involution in aged mice results in decreased T cell output and immune function. Here we use gene expression profiling of FACS sorted thymic stromal subsets to identify molecular mediators of thymocyte: stromal cell interactions, as well as gene expression changes thymic stromal subsets during early stages of thymic involution . We used microarrays to analyze gene expression differences between thymic stromal subsets from male C57BL/6J mice 1, 3, and 6 months of age. Thymic stromal subsets (cTEC, mTEClo, mTEChi, Sirpa-DC, Sirpa+DC, and fibroblasts) were isolated from two 1-, 3-, and 6- month old male C57BL/6J mice. After enzymatic digestion of the thymi, the stromal cells were FACS purified, and RNA was extracted, amplified, labeled and hybridized to Affymetrix mouse 430 2.0 arraysarrays. Raw data were uploaded to Gene Expression Commons for normalization. Both raw CEL and normalized datasets from the 36 samples are included. A model within Gene Expression Commons has been created for analyses/comparisons of these datasets, along with previously reported thymocyte subset datasets. The model within Gene Expression Commons thus contains 6 thymic stromal populations, each from mice 1, 3, and 6 months of age, with duplicates for each datset.
2014-09-12 | E-GEOD-56928 | biostudies-arrayexpress
Project description:Transcriptome analysis of conventional dendritic cells (cDCs) introduced into the thymic microenvironment of re-aggregated thymic organ cultures (RTOCs)
| PRJNA689792 | ENA
Project description:Developmental potential is progressively restricted after germ layer specification during gastrulation. However, cranial neural crest cells challenge this paradigm, as they develop from anterior ectoderm yet give rise to both mesodermal derivatives of the craniofacial skeleton and ectodermal derivatives of the peripheral nervous system. How cranial neural crest cells differentiate into multiple lineages is poorly understood. Here, we demonstrate that cranial neural crest cells possess a transient state of increased chromatin accessibility; and that the earliest premigratory neural crest are biased towards either a neuronal or ectomesenchymal fate, with each lineage expressing distinct factors from the pluripotent state. We profile the spatiotemporal emergence of each neural crest population and demonstrate that the ectomesenchymal lineage forms prior to the neuronal progenitors. Expression of the pluripotency microRNA family miR-302 is maintained in cranial neural crest cells and genetic deletion leads to precocious specification of the ectomesenchymal lineage. We find that miR-302 directly targets Sox9 to slow the timing of ectomesenchyme induction and regulates multiple genes involved in chromatin condensation to maintain accessibility for neuronal differentiation. Loss of mir-302 results in reduced chromatin accessibility in the neuronal progenitor lineage of neural crest and a reduction in peripheral neuron differentiation. Our findings reveal a post-transcriptional mechanism governed by miRNAs from pluripotency as an important mechanism to expand developmental potential of cranial neural crest.
2022-10-25 | GSE215977 | GEO
Project description:Developmental potential is progressively restricted after germ layer specification during gastrulation. However, cranial neural crest cells challenge this paradigm, as they develop from anterior ectoderm yet give rise to both mesodermal derivatives of the craniofacial skeleton and ectodermal derivatives of the peripheral nervous system. How cranial neural crest cells differentiate into multiple lineages is poorly understood. Here, we demonstrate that cranial neural crest cells possess a transient state of increased chromatin accessibility; and that the earliest premigratory neural crest are biased towards either a neuronal or ectomesenchymal fate, with each lineage expressing distinct factors from the pluripotent state. We profile the spatiotemporal emergence of each neural crest population and demonstrate that the ectomesenchymal lineage forms prior to the neuronal progenitors. Expression of the pluripotency microRNA family miR-302 is maintained in cranial neural crest cells and genetic deletion leads to precocious specification of the ectomesenchymal lineage. We find that miR-302 directly targets Sox9 to slow the timing of ectomesenchyme induction and regulates multiple genes involved in chromatin condensation to maintain accessibility for neuronal differentiation. Loss of mir-302 results in reduced chromatin accessibility in the neuronal progenitor lineage of neural crest and a reduction in peripheral neuron differentiation. Our findings reveal a post-transcriptional mechanism governed by miRNAs from pluripotency as an important mechanism to expand developmental potential of cranial neural crest.
2022-10-25 | GSE216136 | GEO
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.
2016-05-06 | GSE81163 | GEO