Project description:Purpose: The goal of this study is to characterise the large variety of stromal cells populations, particularly cortex (cTECs) and medullary (mTECs) epithelial cells. It has been speculated that mTECs and cTECs are composed of functionally distinct subsets with different clonogenic potential. Methods: FACS-isolation protocol to separate 4 different epithelial cells populations from total dissociation of human thymus that is negative for hCD45 then loaded into the 10x Genomics Chromium Platform, and sequenced using Illumina HiSeq 4000. Conclusions: Our study dissected common clusters to human thymic epithelial cells in cortex and medulla containing stem cells markers conserved when expanded in vitro, as well as identified specialised cell clusters in each of the two compartment
Project description:The thymus is extremely sensitive to damage but also has a remarkable ability to repair itself. However, the mechanisms underlying this endogenous regeneration remain poorly understood and this capacity diminishes considerably with age. To identify alternate regeneration pathways in the thymus, we performed an unbiased transcriptome analysis of the non-hematopoietic (CD45-) stromal cell compartment of the thymus, which is less sensitive to thymic damage compared to the CD45+ hematopoietic compartment. Concentrating on a model of thymic damage caused by a sublethal dose of total body irradiation (SL-TBI), where after an initial depletion of thymic cellularity with regeneration initiated after a nadir between days 3-4 and complete recovery by day 42, we found significant upregulation at both days 4 and 7 of several genes known to be involved in thymic function.
Project description:The thymic stroma provides the microenvironment for T cell lineage commitment, development, maturation, and repertoire selection. While the thymic epithelial cell (TEC) compartment is relatively well characterised, a comparably detailed analysis of the non-TEC stromal compartment including the endothelial cells and fibroblasts is currently lacking. Here, we probe the composition of thymic mesenchymal cells and their dynamic change during thymus organogenesis. Using a single cell transcriptomic approach, we identify previously unappreciated heterogeneity within the non-TEC stromal compartment and demonstrate dynamic shifts within non-TEC stromal cell populations over thymic development. We then use a compound heterozygous model (Tbx1+/-Crkl+/-) for 22q11.2DS syndrome to show that significant reductions of multiple mesenchymal subpopulations associated with functional defects and accelerated aging are associated with the thymic hypoplasia observed in this condition. Thus, we provided a comprehensive picture of non-TEC thymic stromal development and their functional defects in a disease model of thymic hypoplasia.
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.
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.
Project description:T cell development and selection is orchestrated in the thymus by a specialized niche of diverse stromal populations. By transcriptional single cell sorting, we de novo characterize the entire stromal compartment of the thymus. We identified dozens of cell states within the thymic stroma, with thymic epithelial cells (TEC) showing the highest degree of heterogeneity. Our analysis highlights four major medullary TEC (mTEC I-IV) populations, with distinct molecular functions, epigenetic landscapes and lineage regulators. Specifically, mTEC-IV constitutes a new and highly divergent TEC lineage with molecular characteristics of the gut chemosensory epithelial tuft cells. Mice deficient of Pou2f3, a tuft cells master regulator, resulted in complete and specific depletion of mTEC-IV, without affecting other TEC populations. Overall, our study comprehensively defines all stroma cells in the thymus and identifies a new TEC lineage associated with chemosensory properties that may potentially link the adaptive immune system to environmental and neurological signals.
Project description:T cell development and selection is orchestrated in the thymus by a specialized niche of diverse stromal populations. By transcriptional single cell sorting, we de novo characterize the entire stromal compartment of the thymus. We identified dozens of cell states within the thymic stroma, with thymic epithelial cells (TEC) showing the highest degree of heterogeneity. Our analysis highlights four major medullary TEC (mTEC I-IV) populations, with distinct molecular functions, epigenetic landscapes and lineage regulators. Specifically, mTEC-IV constitutes a new and highly divergent TEC lineage with molecular characteristics of the gut chemosensory epithelial tuft cells. Mice deficient of Pou2f3, a tuft cells master regulator, resulted in complete and specific depletion of mTEC-IV, without affecting other TEC populations. Overall, our study comprehensively defines all stroma cells in the thymus and identifies a new TEC lineage associated with chemosensory properties that may potentially link the adaptive immune system to environmental and neurological signals.
Project description:T cell development and selection is orchestrated in the thymus by a specialized niche of diverse stromal populations. By transcriptional single cell sorting, we de novo characterize the entire stromal compartment of the thymus. We identified dozens of cell states within the thymic stroma, with thymic epithelial cells (TEC) showing the highest degree of heterogeneity. Our analysis highlights four major medullary TEC (mTEC I-IV) populations, with distinct molecular functions, epigenetic landscapes and lineage regulators. Specifically, mTEC-IV constitutes a new and highly divergent TEC lineage with molecular characteristics of the gut chemosensory epithelial tuft cells. Mice deficient of Pou2f3, a tuft cells master regulator, resulted in complete and specific depletion of mTEC-IV, without affecting other TEC populations. Overall, our study comprehensively defines all stroma cells in the thymus and identifies a new TEC lineage associated with chemosensory properties that may potentially link the adaptive immune system to environmental and neurological signals.
Project description:The thymus is primarily responsible for generating naïve, self-tolerant T cells from hematopoietic precursors. Thymic epithelial cells (TECs) together with other stromal cells create a specialized microenvironment which orchestrates the major selection processes for T cell development. Thymic function progressively deteriorates as part of the aging process, with a dramatic loss in TECs and T cell production, and this ultimately constrains the host immune repertoire. We have previously demonstrated the role of sex steroids in thymic involution in male mice, with surgical castration of middle-aged (9-12 month) male mice resulting in thymus regeneration, peaking around day 28. We have also demonstrated phenotypic alterations in TEC subsets within one week following castration that may contribute to this transient thymus regeneration effect. In this study, we aimed to examine genetic alterations in TEC and non-TEC stromal cell subsets (predominantly fibroblasts and endothelial cells) during age-related thymic involution (5-6 week old young adults compared to 9-12 month middle aged); and genetic changes in TEC and non-TEC at several timepoints following castration, to identify factors that may be involved in thymus regeneration.