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. Overall design: 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.
Transcriptome sequencing of neonatal thymic epithelial cells.
Specimen part, Cell line, Subject
View SamplesThis 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.
Detection of Quiescent Radioresistant Epithelial Progenitors in the Adult Thymus.
Specimen part, Subject
View SamplesPurpose: Cortical thymic epithelial cells (cTECs) contain a unique type of proteasomes, thymoproteasomes. Indirect evidence suggests that the key role of PSMB11, a catalytic subunit of thymoproteasomes specific to cTECs, is to generate a unique repertoire of MHC I peptides. Notably, PSMB11-deficient mice display defective development of CD8 thymocytes. The objective of this study was to characterize the impact of PSMB11 on cTECs and thymocyte development. Since different types of proteasomes have non-redundant effects on gene expression, we hypothesized that thymoproteasomes should have a distinct impact on the transcriptome and thereby the function of cTECs. Results: We report that PSMB11 in cortical thymic epithelial cells has dramatic effects on cTECs on both CD4 and CD8 thymocyte populations. PSMB11 modulates the expression of 850 genes in cTECs, 582 in CD4 thymocytes and 284 in CD8 thymocytes. PSMB11-regulated cTEC genes are involved mainly in cell-cell adhesion, extracellular matric organization and thymocyte chemotaxis. PSMB11-deficient cTECs acquire features of mTECs and perturb thymocyte development. Deletion of PSMB11 causes a major cell stress in both CD4 and CD8 thymocyte populations. Of note, PSMB11-deficiency had no impact on medullary thymic epithelial cells (mTECs), which originate from progenitors that express PSMB11 early in ontogeny. Conclusion: We conclude that PSMB11 has pervasive effects on both CD4 and CD8 thymocytes via regulation of gene expression in cTECs. Overall design: We performed RNA-sequencing in triplicate on cTECs, mTECs, and SM, M1 and M2 thymocytes from the CD4 and CD8 lineages, in order to identify differential gene expression between WT and Psmb11-deficient mice.
PSMB11 Orchestrates the Development of CD4 and CD8 Thymocytes via Regulation of Gene Expression in Cortical Thymic Epithelial Cells.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Polycomb function during oogenesis is required for mouse embryonic development.
Specimen part, Treatment
View SamplesIn mammals, totipotent pre-implantation embryos are formed by fusion of highly differentiated oocytes and spermatozoa. Acquisition of totipotency concurs with remodeling of chromatin states of parental genomes (epigenetic reprogramming), changes in maternally contributed transcriptome and proteome, and zygotic genome activation. Genomes of mature germ cells are more proficient in supporting embryonic development than those of somatic cells. It is currently unknown whether transgenerational inheritance of chromatin states present in mature gametes underlies the efficacy of early embryonic development after natural conception. Here, we show that Ring1 and Rnf2, two core components of the Polycomb Repressive Complex 1 (PRC1), serve redundant gene regulatory functions during oogenesis that are required to support embryonic development beyond the two-cell stage. Numerous developmental regulatory genes that are established Polycomb targets in various somatic cell types are de-repressed in Ring1/Rnf2 double mutant (dm) fully grown germinal vesicle (GV) oocytes. Translation of tested aberrant maternal transcripts is, however, delayed until after fertilization. Exchange of maternal pro-nuclei between control and Ring1/Rnf2 maternally dm early zygotes demonstrates an essential role for Ring1 and Rnf2 during oogenesis in defining cytoplasmic and nuclear maternal contributions that are both essential for proper initiation of embryonic development. A large number of genes up-regulated in Ring1/Rnf2 dm GV oocytes harbor PRC2-mediated histone H3 lysine 27 trimethylation (H3K27me3) in spermatozoa and in embryonic stem cells (ESCs), and are repressed during normal oogenesis and early embryogenesis. These data strongly support the model that Polycomb acts in the female and male germline to silence differentiation inducing genes and to program chromatin states, thereby sustaining developmental potential across generations.
Polycomb function during oogenesis is required for mouse embryonic development.
Specimen part
View SamplesIn mammals, totipotent pre-implantation embryos are formed by fusion of highly differentiated oocytes and spermatozoa. Acquisition of totipotency concurs with remodeling of chromatin states of parental genomes (epigenetic reprogramming), changes in maternally contributed transcriptome and proteome, and zygotic genome activation. Genomes of mature germ cells are more proficient in supporting embryonic development than those of somatic cells. It is currently unknown whether transgenerational inheritance of chromatin states present in mature gametes underlies the efficacy of early embryonic development after natural conception. Here, we show that Ring1 and Rnf2, two core components of the Polycomb Repressive Complex 1 (PRC1), serve redundant gene regulatory functions during oogenesis that are required to support embryonic development beyond the two-cell stage. Numerous developmental regulatory genes that are established Polycomb targets in various somatic cell types are de-repressed in Ring1/Rnf2 double mutant (dm) fully grown germinal vesicle (GV) oocytes. Translation of tested aberrant maternal transcripts is, however, delayed until after fertilization. Exchange of maternal pro-nuclei between control and Ring1/Rnf2 maternally dm early zygotes demonstrates an essential role for Ring1 and Rnf2 during oogenesis in defining cytoplasmic and nuclear maternal contributions that are both essential for proper initiation of embryonic development. A large number of genes up-regulated in Ring1/Rnf2 dm GV oocytes harbor PRC2-mediated histone H3 lysine 27 trimethylation (H3K27me3) in spermatozoa and in embryonic stem cells (ESCs), and are repressed during normal oogenesis and early embryogenesis. These data strongly support the model that Polycomb acts in the female and male germline to silence differentiation inducing genes and to program chromatin states, thereby sustaining developmental potential across generations.
Polycomb function during oogenesis is required for mouse embryonic development.
Treatment
View SamplesAnalysis of estrogen receptor (ER)-positive MCF7 cell total RNA expression and polysome-assiciated RNA expression following treatment with estradiol (E2) and vehicle (etoh).
Estrogen coordinates translation and transcription, revealing a role for NRSF in human breast cancer cells.
Cell line
View SamplesA Single Cell Analysis of Myogenic Dedifferentiation Induced by Small Molecules An important direction in chemical biology is the derivation of compounds that affect cellular differentiation or its reversal. The fragmentation of multinucleate myofibers into viable mononucleates (called cellularisation) occurs during limb regeneration in urodele amphibians and the isolation of myoseverin, a tri-substituted purine that could apparently activate this pathway of myogenic dedifferentiation in mammalian cells, generated considerable interest. We have explored the mechanism and outcome of cellularisation at a single cell level, and report findings that significantly extend the previous work with myoseverin. Using a panel of compounds, including a novel triazine compound called 109 with structural similarity and comparable activity to myoseverin, we have identified microtubule disruption as critical for activation of the response. Our analysis has included the related control triazine compound 401, and the microtubule disrupting agent nocodazole. Time-lapse microscopy has enabled us to analyse the fate of identified mononucleate progeny, and directly assess the extent of dedifferentiation.
A single-cell analysis of myogenic dedifferentiation induced by small molecules.
Specimen part, Cell line, Compound, Time
View SamplesAnalysis of tissues of DBA/2 mice fed a standard breeding diet (SBD) and high fat diet (HFD) revealed tissue specific roles in inflammation and disease, and altered communication between tissues. The tissues surveyed incuded adipose tissues (brown, inguinal, mesenteric, retro-peritoneal, subcutaneious and gonadal), muscle and liver.
High-fat diet leads to tissue-specific changes reflecting risk factors for diseases in DBA/2J mice.
Specimen part, Treatment
View SamplesSilencing HoxA1 in vivo by intraductal delivery of nanoparticle-formulated siRNA reduced mammary tumor incidence by 75% , reduced cell proliferation, and prevented loss of ER and PR expression.
Silencing HoxA1 by intraductal injection of siRNA lipidoid nanoparticles prevents mammary tumor progression in mice.
Age, Specimen part
View Samples