The goal of our study was to evaluate at the systems-level, the effect of sex hormones on thymic epithelial cells (TECs). To this end, we sequenced the transcriptome of cortical and medullary TECs (cTECs and mTECs) from three groups of 6 month-old mice: males, females and males castrated at four weeks of age. In parallel, we analyzed variations in the size of TEC subsets in those three groups between 1 and 12 months of age. We report that sex hormones have pervasive effects on the transcriptome of TECs: the number of differentially expressed genes was 1,440 in cTECs and 1,783 in mTECs. Sexual dimorphism was particularly conspicuous in cTECs. Male cTECs displayed low proliferation rates that correlated with low expression of Foxn1 and its main targets. Furthermore, male cTECs expressed relatively low levels of genes instrumental in thymocyte expansion (e.g., Dll4) and positive selection (Psmb11 and Ctsl). Nevertheless, cTECs were more abundant in males than females. Accumulation of cTECs in males correlated with differential expression of genes regulating cell survival and cell differentiation. Unexpectedly, we observed that female and male sex hormones repressed promiscuous gene expression in mTECs. Since sex hormones did not affect the expression of Aire per se, they must impinge on the activity of unidentified regulator(s) of promiscuous gene expression in mTECs. The sexual dimorphism of TECs highlighted here may be mechanistically linked to the well-recognized sex differences in susceptibility to infections and autoimmune diseases. Overall design: Cortical and medullary thymic epithelial cells from 6 month-old male, female and castrated male mice were sequenced in 3 replicates (but only 2 replicates for castrated male mTECs).
Thymic Mesenchymal Cells Have a Distinct Transcriptomic Profile.
No sample metadata fields
View SamplesThymocytes were extracted from a pool of three 8-12 week old C57BL-6 female mice. Cells were separated from stroma by gently crushing the thymi in between 2 microslides. RNA from thymocytes was extracted using the Trizol reagent and protocol, and analysed using the Illumina HiSeq 2000. Overall design: Transcriptomic analysis of a single replicate of thymocytes from a pool of three 8-12 week old C57BL-6 female mice, using the Illumina HiSeq 2000
Thymic Mesenchymal Cells Have a Distinct Transcriptomic Profile.
Specimen part, Cell line, Subject
View SamplesAlthough heterochromatin is enriched with repressive traits, it is also actively transcribed, giving rise to large amounts of non-coding RNAs. Although these RNAs are responsible for the formation and maintenance of heterochromatin, little is known about how their transcription is regulated. Here we show that the Snail1 transcription factor represses pericentromeric transcription, acting through the H3K4 deaminase LOXL2. Since Snail1 plays a key role in the epithelial to mesenchymal transition (EMT), we analyzed the regulation of mouse heterochromatin transcription in this process. At the onset of EMT, one of the major structural heterochromatin proteins, HP1a, is transiently released from heterochromatin foci in a Snail1/LOXL2dependent manner during EMT, concomitantly with a down-regulation of major satellite transcription. Global transcriptome analysis indicated that ectopic expression of heterochromatin transcripts affects the transcription profile of EMT-related genes. Additionally, preventing the down-regulation of major satellite transcripts compromised the migratory and invasive behavior of mesenchymal cells. We propose that Snail1 regulates heterochromatin transcription through the histone-modifying enzyme, LOXL2, thus creating the favorable transcriptional state necessary for completing EMT.
Regulation of heterochromatin transcription by Snail1/LOXL2 during epithelial-to-mesenchymal transition.
Cell line, Treatment
View SamplesGene expression patterns of Crohn's disease (CD) and ulcerative colitis (UC) colonic specimens were analyzed using whole-genome microarrays. Healthy control samples were included in order to detect gene expression changes associated with CD or UC. CD and UC samples were also compared in order to identify the molecular mechanisms that distinguish both fenotypes of inflammatory bowel disease.
Identification of novel predictor classifiers for inflammatory bowel disease by gene expression profiling.
Sex, Disease
View SamplesEfficient growth cone regeneration requires protein synthesis in the adult mammalian brain and spinal cord. Recent evidence suggests that the local availability of protein synthesis machinery in adult mammalian axons may be an indicator of their regenerative capacity. Here we investigated the local protein synthesis capacity in matured cortical axons, which have poor regenerative capacity, yet are critical for recovery following injury due to traumatic brain injury and stroke. This work is the first to biochemically isolate and identify mRNA from mammalian cortical axons, making use of a unique microfluidic platform to isolate axons free of other cellular debris. We first sought to identify mRNA in nave axons that makes up the pool of mRNA available for translation initiated following axotomy. Next, we investigated changes in the mRNA population localized to axons 2 days following axotomy and growth cone regeneration.
Axonal mRNA in uninjured and regenerating cortical mammalian axons.
No sample metadata fields
View SamplesEnvironmental enrichment has been shown to induce wholescale alterations to the gene expression profile of experimental animals
The impact of environmental enrichment on the murine inflammatory immune response.
Sex, Age
View SamplesPurpose: 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 SamplesAs regulators of protein degradation, proteasomes regulate practically all cellular functions. It is therefore logical to assume that replacement of the constitutive proteasome (CP) by its IFN- inducible homolog immunoproteasome (IP) could have far reaching effects on cell function. Accordingly, recent studies have revealed important roles for IPs in immune cells beyond MHC I-peptide processing. Moreover, the expression of IPs in non-immune cells from non-inflamed tissues suggests that the involvement of IPs is not limited to the immune system. We demonstrate here that IP-deficiency affects the transcription of 8104 genes in maturing dendritic cells (DCs). This occurs mainly through non-redundant regulation of key immune-related transcription factors by CPs and IPs. Additionally, IP-deficiency decreases DC''s efficiency to activate CD8+ T cells in vivo. Our study reveals that the broad cellular roles of IPs could rely on transcription regulation and, more importantly, illustrates how IP-deficiency could generate MHC I-peptide processing-independent phenotypes. Overall design: Examination of the transcriptome of WT and immunoproteasome-deficient cells at 4 different time points of dendritic cell maturation, in 4 experimental replicates (total of 32 samples).
Immunoproteasomes shape the transcriptome and regulate the function of dendritic cells.
No sample metadata fields
View SamplesAcetylation and deacetylation of histones and other proteins depend on the opposing activities of histone acetyltransferases and histone deacetylases (HDACs), leading to either positive or negative gene expression changes. The use of HDAC inhibitors (HDACi) has uncovered a role for HDACs in the control of proliferation, apoptosis and inflammation. However, little is known of the roles of specific HDACs in intestinal epithelial cells (IEC). We investigated the consequences of ablating both Hdac1 and Hdac2 in murine IECs gene expression.
HDAC1 and HDAC2 restrain the intestinal inflammatory response by regulating intestinal epithelial cell differentiation.
Specimen part
View SamplesStatins and bisphosponates (BPs) are two distinct classes of isoprenoid pathway inhibitors targeting HMG-CoA reductase (upstream enzyme) and Farnesyl-pyrophospate synthase (downstream enzyme) respectively. Here we conducted a comparative study of two representatives of these classes, fluvastatin (Fluva) and Zoledronate (Zol), to assess the differences in their in vivo metastatic potentials and pharmacogenomic profiles. Both drugs, being administered after emergence of detectable metastases, appeared to be potent metastasis inhibitors in MDA-MB-231 breast cancer metastasis model. We observed a reduced number of metastatic sites under Fluva, but not Zol treatment. Combinatorial in vivo treatment by Fluva and Zol showed no synergy for these drugs, as reported earlier on the basis of in vitro studies (Budman DR, Oncology 2006), staying in line with similarity of their transcriptomic profiles. Comparison of Zol and Fluva transcriptomic profiles revealed similar patterns of affected genes (describe involved genes functions) through different kinetics (when treated with IC50 determined for 72h treatment, the majority of changes were observed after 24h incubation with Fluva , and only after 48h incubation with Zol at 72h-IC50 or after 24h treatment with its 3 times higher dose). We demonstrated here that targeting different enzymes of the same pathway neither necessarily leads to distinct changes in gene profiles, nor to synergy for in vivo anti-metastatic potential.
Transcriptome analysis and in vivo activity of fluvastatin versus zoledronic acid in a murine breast cancer metastasis model.
Cell line, Time
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