Transcription factors that regulate quiescence, proliferation, and homing of lymphocytes are critical for effective immune system function. In the present study, we demonstrated that the transcription factor ELF4 directly activates the tumor suppressor KLF4 downstream of T cell receptor (TCR) signaling to induce cell cycle arrest in nave CD8+ T cells. Elf4- and Klf4-deficient mice accumulated CD8+CD44hi T cells during steady-state conditions and generated more memory T cells after immunization. The homeostatic expansion of CD8+CD44hi T cells in Elf4-null mice resulted in a redistribution of cells to non-lymphoid tissue due to reduced expression of the transcription factor KLF2, and the surface proteins CCR7 and CD62L. This work describes the combinatorial role of lymphocyte-intrinsic factors in the control of T cell homeostasis, activation and homing.
Transcription factor ELF4 controls the proliferation and homing of CD8+ T cells via the Krüppel-like factors KLF4 and KLF2.
Specimen part
View SamplesFollowing the identification of a critical time window of Blood Brain Barrier formation in the mouse embryo, we aimed to identify genes important for barriergenesis. To this end, we isolated cortical and lung E13.5 endothelial cells and compared expression between the two populations.
Mfsd2a is critical for the formation and function of the blood-brain barrier.
Specimen part
View SamplesBackground: The vast majority of human genes (.70%) are alternatively spliced. Although alternative pre-mRNA processing is modified in multiple tumors, alternative hyper-splicing signatures specific to particular tumor types are still lacking. Here, we report the use of Affymetrix Human Exon Arrays to spot hyper-splicing events characteristic of myasthenia gravis (MG)-thymoma, thymic tumors which develop in patients with MG and discriminate them from colon cancer changes. Methodology/Principal Findings: We combined GO term to parent threshold-based and threshold-independent ad-hoc functional statistics with in-depth analysis of key modified transcripts to highlight various exon-specific changes. These denote alternative splicing in MG-thymoma tumors compared to healthy human thymus and to in-house and Affymetrix datasets from colon cancer and healthy tissues. By using both global and specific, term-to-parent Gene Ontology (GO) statistical comparisons, our functional integrative ad-hoc method allowed the detection of disease-relevant splicing events. Conclusions/Significance: Hyper-spliced transcripts spanned several categories, including the tumorogenic ERBB4 tyrosine kinase receptor and the connective tissue growth factor CTGF, as well as the immune function-related histocompatability gene HLA-DRB1 and interleukin (IL)19, two muscle-specific collagens and one myosin heavy chain gene; intriguingly, a putative new exon was discovered in the MG-involved acetylcholinesterase ACHE gene. Corresponding changes in spliceosome composition were indicated by co-decreases in the splicing factors ASF/SF2 and SC35. Parallel tumor-associated changes occurred in colon cancer as well, but the majority of the apparent hyper-splicing events were particular to MGthymoma and could be validated by Fluorescent In-Situ Hybridization (FISH), Reverse TranscriptionPolymerase Chain Reaction (RT-PCR) and mass spectrometry (MS) followed by peptide sequencing. Our findings demonstrate a particular alternative hyper-splicing signature for transcripts over-expressed in MG-thymoma, supporting the hypothesis that alternative hyper-splicing contributes to shaping the biological functions of these and other specialized tumors and opening new venues for the development of diagnosis and treatment approaches
Identifying alternative hyper-splicing signatures in MG-thymoma by exon arrays.
Sex
View SamplesThe proneural NEUROG2 is essential for neuronal commitment, cell cycle exit and neuronal differentiation. Characterizing genes networks regulated downstream of NEUROG2 is therefore of prime importance. To identify NEUROG2 early response genes, we combined gain of function in the neural tube with a global detection of modified transcripts using microarrays. We included in our study a mutant form of NEUROG2 (NEUROG2AQ) that cannot bind DNA and cannot trigger neurogenesis. Using this approach, we identified 942 genes modified at the onset of NEUROG2 activation. The global analysis of functions regulated by NEUROG2 allowed unmasking its rapid impact on cell cycle control. We found that NEUROG2 specifically represses a subset of cyclins acting at the G1 and S phases of the cell cycle, thereby impeding S phase re-entry. This repression occurs before modification of p27kip1, indicating that the decision to leave the cell cycle precedes the activation of this Cyclin-dependant Kinase Inhibitor. Moreover, NEUROG2 down-regulates only one of the D-type cyclins, cyclinD1, and maintaining cyclinD1 blocks the ability of the proneural to trigger cell cycle exit, without altering its capacity to trigger neuronal differentiation. The fact that NEUROG2 represses a subset but not all cell cycle regulators indicates that cell cycle exit is not an indirect consequence of neuronal differentiation but is precisely controlled by NEUROG2. Altogether our findings indicate that NEUROG2, by specifically repressing G1 and S cyclins, allows committed neuronal precursors to perform their last mitosis but blocks their re-entry in the cell cycle, thus favouring cell cycle exit.
NEUROG2 drives cell cycle exit of neuronal precursors by specifically repressing a subset of cyclins acting at the G1 and S phases of the cell cycle.
Specimen part, Treatment
View SamplesWe have previously isolated a murine erythroleukemia cell line refractive to re-enter a cell differentiation program as opposite to the progenitor cell line. We use RNA-seq to identify differentially expressed genes in both cell lines Overall design: Gene expression levels from MEL DS19 and MEL-R cell cultures were compared by next generation sequencing using standard RNA-seq protocols
Differential gene expression analysis by RNA-seq reveals the importance of actin cytoskeletal proteins in erythroleukemia cells.
Specimen part, Cell line, Subject
View SamplesAPC is a key regulator of canonical Wnt signalling since it participates to beta-catenin targeting to proteasomal degradation when the pathway is inactive. Moreover, independently of Wnt signaling, APC regulates several cellular functions such as mycrotubule dynamics, chromosome segregation, cell adhesion. Although APC has been widely studied for its implication in initation and progression of several cancers, its role in satellite cells (skeletal muscle stem cells) has never been investigated.
APC is required for muscle stem cell proliferation and skeletal muscle tissue repair.
Specimen part
View SamplesSCL/TAL1, a tissue-specific transcription factor of the basic helix-loop-helix (bHLH) family, and c-Kit, a tyrosine kinase receptor, control hematopoietic stem cell survival and quiescence. Here we report that SCL and c-Kit signaling control a common gene expression signature, of which 19 genes are associated with apoptosis. In vivo, SCL levels are limiting for the clonal expansion of Kit+ multipotent and erythroid progenitors. In addition, increased SCL expression specifically enhances the sensitivity of multipotent and megakaryocyte/erythroid progenitors to Steel factor (KIT ligand), whilst a DNA binding mutant antagonizes KIT function and induces apoptosis in progenitors. We conclude that Scl operates downstream of Kit to support the survival of megakaryocyte/erythroid progenitors. Finally, higher SCL expression upregulates Kit in normal bone marrow cells and increases chimerism after bone marrow transplantation, indicating that Scl is also upstream of Kit. We conclude that Scl and Kit establish a positive feedback loop in multipotent and megakaryocyte/erythroid progenitors.
Genetic interaction between Kit and Scl.
Cell line, Treatment
View SamplesPurpose: Conducted expression profiling by RNA-seq as unbiased screen to identify genes that are altered in motor neurons of PbxMN? mice at e12.5 at brachial and thoracic levels of the spinal cord. Because loss of Pbx genes affects MN organization at all rostrocaudal levels, we focused on genes whose profiles were altered at both brachial and thoracic levels. Methods: We compared gene expression profiles in MNs isolated from control Hb9::GFP and PbxMN?; Hb9::GFP embryos at e12.5. MNs were purified by FACS, and RNA was extracted from 9 PbxMN?; Hb9::GFP and 9 control Hb9::GFP embryos at brachial and thoracic levels using the Arcturus Picopure RNA isolation kit. 10ng of RNA was pooled from 3 RNA samples of each genotype, and used to amplify 100ng of cDNA using Nugene''s Ovation RNA-Seq System V2 kit, 100ng of cDNA for each sample was used as in input to prepare 12 bar coded libraries using the Ovation Ultralow Library system. We then performed expression profiling by RNA-seq. The samples were mixed into two pools and run on two 50-nucleotide paired end read rapid run flow cell lanes with the Illumina HiSeq 2500 sequencer. Generating on average 74 and 101 million reads passing filter for brachial and thoracic samples respectively. Results: This analysis yielded 64 brachial and 124 thoracic genes that were differentially expressed with a stringent cutoff of padj.<0.05. Of these genes, we found 31 genes in common between the two, brachial and thoracic, levels of the spinal cord that may play a role in motor neuron columnar organization. Furthermore our expression profiling of control brachial and control thoracic MNs identified 61 genes with (padj.<0.05), that represent distinct molecular profiles of MNs generated at brachial and thoracic levels which may be used to further characterize MNs involved in forelimb and thoracic innervation. Conclusions: Our study represents a detailed transcriptional analysis of embryonic spinal motor neurons and revealed a number of novel motor neuron-specific genes that are under transcriptional regulation of Pbx genes. Overall design: Examination of embryonic spinal MN expression profiles at 2 different spinal cord levels, brachial and thoracic. From RNA collected from 9 pooled Control and 9 PbxMN? e12.5 Hb9::GFP FACS MNs.
Parallel Pbx-Dependent Pathways Govern the Coalescence and Fate of Motor Columns.
Specimen part, Cell line, Subject
View SamplesThe human C-type lectin Reg3a (HIP/PAP) is an antimicrobial peptide that kills Gram-positive bacteria. Reg3a preserves gut microbiota homeostasis, reinforces intestinal barrier function and thereby helps to fight induced colitis in mice.
Enteric Delivery of Regenerating Family Member 3 alpha Alters the Intestinal Microbiota and Controls Inflammation in Mice With Colitis.
Specimen part, Treatment
View SamplesObjective: the objective of this work was to determine different gene expression patterns in small bowel grafts biopsies with “minimal changes” histology that could identify patients with high rejection risk Methods: 24 samples (17 stable and 7 non stable grafts) from 8 adult patients with small bowel transplantation were included for RNA-Sequencing.Total RNA extracted from intestinal biopsies was used with the TruSeq RNA Sample Preparation v2 Kit to construct index-tagged cDNA libraries. Libraries were sequenced on the Genome Analyzer IIx following the standard RNA sequencing protocol with the TruSeq SBS Kit v5. Fastq files containing reads for each library were extracted and demultiplexed using Casava v1.8.2 pipeline. Sequencing adapter contaminations were removed from reads using Cutadapt software v1.6 and the resulting reads were aligned to the reference human genome (Ensembl gene-build GRCh37.75) using TopHat2 v2.0.13. Gene expression values were calculated as counts using HTSeq v0.6.1. Only genes with at least 1 count per million in all samples were considered for statistical analysis. Data were then normalized and differential expression tested using the R Bioconductor package edgeR. We selected all biopsies from 4 of the patients (18 biopsies, 11 stable and 7 non stable) as the discovery set. The other 6 biopsies from 4 patients (all stable) were used as the test set. Differences in the discovery set were tested by generalized linear model analysis,and results were considered significant when the Benjamini-Hochberg adjusted p-value was < 0,05. Results: We obtained 816 differentially expressed genes (DEGs) between stable and non stable biopsies in the discovery set: 369 upregulated and 447 downregulated in the non stable group. The classification and prediction with the Nearest Shrunken Centroids method identified 5 genes (ADH1C, CYP4F2, PDZK1, SLC39A4 and OPTN) from the 816 DEGs that could classify both groups with an error rate of 11% and classified correctly all samples from the test set. These results were confirmed by Supoprted Vector Machine (SVM), bagSVM and Random Forest methods, showing high accuracy, sensitivity and specificity. Conclusions: We identified 5 genes from the DEGs as possible biomarkers to classify patients with normal histology that could be however in a higher risk of rejection. In this way, gene expression assays are powerful tools with high sensitivity that allow more accurate diagnosis. Overall design: The study included 24 samples from 8 adult patients with small bowel transplantation. Samples correspond to RNA extracted from intestinal biopsies obtained at different post-transplantation time. All biopsies have an histological diagnosis of "minimal changes" and they were classified in two groups according their immunological stability (stable and non stable). Stable group comprised biopsies of patients that never rejected and biopsies obtained at least 15 days after rejection if no other rejection episode occurred in at least the next six months. Non stable group included biopsies obtained between rejection episodes (separated less than six months) and also those biopsies collected within the 15 days before the first rejection episode.
5-gene differential expression predicts stability of human intestinal allografts.
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