Interactions between Chronic Lymphocytic Leukemia B-cells (CLL B-cells) and the microenvironment (ME) play a major function in the physiopathology of CLL. Extracellular vesicles (EVs) (composed of exosomes and microparticles) have been shown to play an important role in cell communication. EVs, purified by ultracentrifugation from bone marrow mesenchymal stromal cells (BM-MSC) culture, were added to CLL B-cells. Microarray study highlighted 805 differentially expressed genes between CLL-B-cells cultured with and without EVs. Of these, CCL3/4, EGR1/2/3, MYC (involved in BCR pathway) were increased while pro-apoptotic genes like HRK were decreased. We showed for the first time the potential of EVs alone to induce gene expression modifications in CLL B-cell, notably in BCR and apoptosis pathways. We concluded that a substantial part of communication between CLL B-cells and BM-ME is mediated through EV.
Extracellular vesicles of bone marrow stromal cells rescue chronic lymphocytic leukemia B cells from apoptosis, enhance their migration and induce gene expression modifications.
Specimen part, Subject
View SamplesMinichromosome maintenance (MCM) proteins facilitate replication by licensing origins and unwinding the DNA double strand. Interestingly, the number of MCM hexamers greatly exceeds the number of firing origins suggesting additional roles of MCMs. Here we show a hitherto unanticipated function of MCM2 in cilia formation in human cells and zebrafish that is uncoupled from replication. Zebrafish depleted of MCM2 develop ciliopathy-phenotypes including microcephaly and aberrant heart looping due to malformed cilia. In non-cycling human fibroblasts, loss of MCM2 promotes transcription of a subset of genes, which cause cilia shortening and centriole overduplication. Chromatin immunoprecipitation experiments show that MCM2 binds to transcription start sites of cilia inhibiting genes. We propose that such binding may block RNA polymerase II-mediated transcription. Depletion of a second MCM (MCM7), which functions in complex with MCM2 during its canonical functions, reveals an overlapping cilia-deficiency phenotype likely unconnected to replication, although MCM7 appears to regulate a distinct subset of genes and pathways. Our data suggests that MCM2 and 7 exert a role in ciliogenesis in post-mitotic tissues. Overall design: 6 samples in total: 3 control, 3 siRNA MCM7
Resting cells rely on the DNA helicase component MCM2 to build cilia.
Specimen part, Cell line, Treatment, Subject
View SamplesMinichromosome maintenance (MCM) proteins facilitate replication by licensing origins and unwinding the DNA double strand. Interestingly, the number of MCM hexamers greatly exceeds the number of firing origins suggesting additional roles of MCMs. Here we show a hitherto unanticipated function of MCM2 in cilia formation in human cells and zebrafish that is uncoupled from replication. Zebrafish depleted of MCM2 develop ciliopathy-phenotypes including microcephaly and aberrant heart looping due to malformed cilia. In non-cycling human fibroblasts, loss of MCM2 promotes transcription of a subset of genes, which cause cilia shortening and centriole overduplication. Chromatin immunoprecipitation experiments show that MCM2 binds to transcription start sites of cilia inhibiting genes. We propose that such binding may block RNA polymerase II-mediated transcription. Depletion of a second MCM (MCM7), which functions in complex with MCM2 during its canonical functions, reveals an overlapping cilia-deficiency phenotype likely unconnected to replication, although MCM7 appears to regulate a distinct subset of genes and pathways. Our data suggests that MCM2 and 7 exert a role in ciliogenesis in post-mitotic tissues. Overall design: 6 samples in total: 3 control, 3 siRNA MCM2
Resting cells rely on the DNA helicase component MCM2 to build cilia.
Specimen part, Cell line, Treatment, Subject
View SamplesThe NF1 tumor suppressor encodes a RAS GTPase-Activating Protein (RasGAP). Accordingly, deregulated RAS signaling underlies the pathogenesis of NF1-mutant cancers. However, while various RAS effector pathways have been shown to function in these tumors, it is currently unclear which specific proteins within these broad signaling pathways represent optimal therapeutic targets. Here we identify mTORC1 as the key PI3K pathway component in NF1-mutant nervous system malignancies and conversely show that mTORC2 and AKT are dispensable. We also report that combined mTORC1/MEK inhibition is required to promote tumor regression in animal models, but only when the inhibition of both pathways is sustained. Transcriptional profiling studies were also used to establish a predictive signature of effective mTORC1/MEK inhibition in vivo. Within this signature, we unexpectedly found that the glucose transporter gene, GLUT1, was potently suppressed but only when both pathways were effectively inhibited. Moreover, unlike VHL and LKB1 mutant cancers, reduction of 18F-FDG uptake measured by FDG-PET required the effective suppression of both mTORC1 and MEK. Together these studies identify optimal and sub-optimal therapeutic targets in NF1-mutant malignancies and define a non-invasive means of measuring combined mTORC1/MEK inhibition in vivo, which can be readily incorporated into clinical trials.
Defining key signaling nodes and therapeutic biomarkers in NF1-mutant cancers.
Specimen part
View SamplesWe have investigated the initial responses in human lung tissue explants to Mtb infection, focusing primarily on gene expression patterns in different tissue resident innate cell types Overall design: Cells sorted from uninfected and infected lung tissue (24 hrs. post infection)
<i>Mycobacterium tuberculosis</i> Invasion of the Human Lung: First Contact.
Specimen part, Subject
View SamplesWe have investigated the initial responses in human lung tissue explants to Mtb infection, focusing primarily on gene expression patterns in different tissue resident innate cell types Overall design: Cells sorted from uninfected and infected lung tissue (24 hrs. post infection)
<i>Mycobacterium tuberculosis</i> Invasion of the Human Lung: First Contact.
Specimen part, Subject
View SamplesEndocycle is an alternative cell cycle during which the DNA is replicated in the absence of cytokinesis, resulting in cellular endopolyploidy. The endocycle is frequenctly observed in plant species that grow under extreme conditions. Thus, endopolyploidy has been postulated to be a mechanism facilitating adaptive growth.
A Spatiotemporal DNA Endoploidy Map of the Arabidopsis Root Reveals Roles for the Endocycle in Root Development and Stress Adaptation.
Specimen part
View SamplesSomatic polyploidy caused by endoreplication is observed in arthropods, molluscs, and vertebrates, but is especially prominent in higher plants where it has been postulated to be essential for cell growth and fate maintenance. However, a comprehensive understanding of the physiological significance of plant endopolyploidy has remained elusive. Here, we modeled and experimentally verified a high-resolution DNA endoploidy map of the developing Arabidopsis thaliana root, revealing a remarkable spatiotemporal control of DNA endoploidy levels across tissues and a strong dependence on stress signals. Cellular and transcriptomic analysis revealed that inhibition of endoreplication onset alters the nuclear-to-cellular volume ratio and change in expression of cell wall modifying genes, correlated with the appearance of cell structural changes. Our data indicate that endopolyploidy might serve to coordinate cell expansion with structural stability, and that spatiotemporal endoreplication pattern changes may buffer for stress conditions, which may explain the widespread occurrence of the endocycle in plant species growing in extreme or variable environments. Overall design: Two biological replicates of Col-0 were compared with three biological replicates of smr1
A Spatiotemporal DNA Endoploidy Map of the Arabidopsis Root Reveals Roles for the Endocycle in Root Development and Stress Adaptation.
Specimen part, Subject
View SamplesWe individually examined the ability of human ARGFX, DPRX, LEUTX, and TPRX1 to regulate gene expression by ectopically expressing these proteins in fibroblasts. Overall design: Each gene along with an empty control vector were transfected individually to drive ectopic expression in human dermal fibroblasts, in triplicate.
Evolutionary origin and functional divergence of totipotent cell homeobox genes in eutherian mammals.
Specimen part, Subject
View SamplesWhile blood transcriptional profiling has improved diagnosis and understanding of disease pathogenesis of adult tuberculosis (TB), no studies applying gene expression profiling of children with TB have been described so far. In this study, we have compared whole blood gene expression in childhood TB patients, as well as in healthy latently infected (LTBI) and uninfected (HC) children in a cohort of Warao Amerindians in the Delta Amacuro in Venezuela. We identified a 116-gene signature set by means of random forest analysis that showed an average prediction error of 11% for TB vs. LTBI and for TB vs. LTBI vs. HC in our dataset. Furthermore, a minimal set of only 9 genes showed a significant predictive value for all previously published adult studies using whole blood gene expression, with average prediction errors between 17% and 23%. Additionally, a minimal gene set of 42 genes with a comparable predictive value to the 116-gene set in both our dataset and the previously published literature cohorts for the comparsion of TB vs. LTBI vs. HC was identified. In order to identify a robust representative gene set that would hold stand among different ethnic populations, we selected ten genes that were highly discriminative between TB, LTBI and HC in all literature datasets as well as in our dataset. Functional annotation of these ten genes highlights a possible role for genes involved in calcium signaling and calcium metabolism as biomarkers for active TB. These ten genes were validated by quantitative real-time polymerase chain reaction in an additional cohort of 54 Warao Amerindian children with LTBI, HC and non-TB pneumonia. Decision tree analysis indicated that five of the ten genes were sufficient to diagnose 78% of the TB cases correctly with 100% specificity. We conclude that our data justify the further exploration of our signature set as biomarkers to diagnose childhood TB. Furthermore, as the identification of different biomarkers in ethnically distinct cohorts is apparent, it is important to cross-validate newly identified markers in all available cohorts.
A predictive signature gene set for discriminating active from latent tuberculosis in Warao Amerindian children.
Sex, Age
View Samples