We have determined the consequences of ICN1 overexpression from retroviral vectors introduced into bone marrow cells.
Oncogenesis of T-ALL and nonmalignant consequences of overexpressing intracellular NOTCH1.
No sample metadata fields
View SamplesActivation of b-catenin has been causatively linked to the etiology of colon cancer. Conditional stabilization of this molecule in pro-T-cells promotes thymocyte development without the requirement for preTCR signaling. We show here that activated b-catenin stalls the developmental transition from the double-positive (DP) to the single-positive (SP) thymocyte stage and predisposes DP thymocytes to transformation. b-Catenin induced thymic lymphomas have a leukemic arrest at the early DP stage. Lymphomagenesis requires Rag activity, which peaks at this developmental stage, as well as additional secondary genetic events. A consistent secondary event is the transcriptional upregulation of c-Myc, whose activity is required for transformation since its conditional ablation abrogates lymphomagenesis. In contrast, the expression of Notch receptors as well as targets is reduced in DP thymocytes with stabilized b-catenin and remains low in the lymphomas indicating that Notch activation is not required or selected for in b-catenin induced lymphomas. Thus, b-catenin activation may provide a mechanism for the induction of T-ALL that does not depend on Notch activation.
Beta-catenin stabilization stalls the transition from double-positive to single-positive stage and predisposes thymocytes to malignant transformation.
No sample metadata fields
View SamplesAlthough transcriptional programs associated with T-cell specification and commitment have been described, the functional hierarchy and the roles of key regulators in structuring/ orchestrating these programs remain unclear. Activation of Notch signaling in uncommitted precursors by the thymic stroma initiates the T-cell differentiation program. One regulator first induced in these precursors is the DNA binding protein Tcf-1, a T-cell specific mediator of Wnt signaling. Yet the specific contribution of Tcf-1 to early T-cell development and the signals inducing it in these cells remain unclear. Here we assign functional significance to Tcf-1 as a gatekeeper of T-cell fate. We show that Tcf-1 is directly activated by Notch signals. Tcf-1 is required at the earliest phase of Tcell determination for progression beyond the early thymic progenitor (ETP) stage. The global expression profile of Tcf-1 deficient progenitors indicates that basic processes of DNA metabolism are downregulated in its absence and the blocked T-cell progenitors become abortive and die by apoptosis. Our data thus add an important functional relationship to the roadmap of T-cell development.
T-cell factor 1 is a gatekeeper for T-cell specification in response to Notch signaling.
Specimen part
View SamplesCell fate decisions depend on the interplay between chromatin regulators and transcription factors. Here we show that activity of the Mi-2u Nucleosome Remodeling and Deacetylase (NuRD) complex is controlled by the Ikaros family of lymphoid-lineage determining proteins. Ikaros, an integral component of the NuRD complex in lymphocytes, tethers this complex to active lymphoid differentiation genes, but keeps it in a functionally-poised state. Loss in Ikaros DNA binding activity causes a local increase in Mi-2u chromatin remodeling, histone deacetylation and suppression of lymphoid gene expression. The NuRD complex also redistributes to transcriptionally-poised non-Ikaros gene targets, involved in proliferation and metabolism, inducing their re-activation. Thus release of NuRD from Ikaros regulation blocks lymphocyte maturation and mediates progression to a leukemic state by engaging functionally-opposing epigenetic mechanisms and genetic networks.
Harnessing of the nucleosome-remodeling-deacetylase complex controls lymphocyte development and prevents leukemogenesis.
Age, Specimen part
View SamplesThere is much controversy about the role of T-regulatory cells (Treg) in human colon cancer. High densities of tumor-infiltrating Treg can correlate with better or worse clinical outcomes depending on the sutdy. Treg have potent anti-inflammatory functions that have been shown to control cancer progression. However, Treg isolated from patient with colon cancer or in mouse models of polyposis do not have the ability to suppress inflammation and instead promote cancer. Gene expression was preformed to determine differences between Treg isolated from healthy mice and Treg isolated from polyp-ridden mice.
Expression of RORγt marks a pathogenic regulatory T cell subset in human colon cancer.
Sex, Age, Specimen part
View SamplesInterleukin (IL)-17 plays an important and protective role in host defence and has been demonstrated to orchestrate airway inflammation by cooperating with and inducing proinflammatory cytokines. Mircoarrays were used to identify immediate-early/ primary response IL-17A-dependent gene transcripts in primary human bronchial ASM cells from mild asthmatic and healthy individuals.
IL-17A mediates a selective gene expression profile in asthmatic human airway smooth muscle cells.
Sex, Age, Specimen part, Treatment, Subject, Time
View SamplesTransgenic expression of TLX1 induces T-cell leukemias in mice.
The TLX1 oncogene drives aneuploidy in T cell transformation.
No sample metadata fields
View SamplesWe used Affymetrix DNA arrays to investigate the extent to which nuclear HDAC4 accumulation affects neuronal gene expression.
HDAC4 governs a transcriptional program essential for synaptic plasticity and memory.
Specimen part
View SamplesGlucosamine proved to be a potent, broad-spectrum inhibitor of IL-1beta. Of the 2,813 genes whose transcription was altered by IL-1beta stimulation (p<0.0001), glucosamine significantly blocked the response in 2,055 (~73%). Glucosamine fully protected the chondrocytes from IL-1-induced expression of inflammatory cytokines, chemokines and growth factors as well as proteins involved in PGE2 and NO synthesis. It also blocked the IL-1-induced expression of matrix specific proteases such as MMPs -3,-9,-10,-12 and ADAMTS-1.
Exogenous glucosamine globally protects chondrocytes from the arthritogenic effects of IL-1beta.
Age
View SamplesImmune-Responsive Gene 1 (Irg1) is a mitochondrial enzyme that produces itaconate under inflammatory conditions principally in cells of myeloid lineage. Cell culture studies suggest that itaconate regulates inflammation through inhibitory effects on cytokine and reactive oxygen species production. To evaluate the functions of Irg1 in vivo, we challenged wild-type (WT) and Irg1 KO mice with Mycobacterium tuberculosis (Mtb) and monitored disease progression. Irg1 KO but not WT mice succumbed rapidly to Mtb, and mortality was associated with increased infection, inflammation, and pathology. Infection of LysM-Cre Irg1 flox, MPR8-Cre Irg1 flox, and CD11c-Cre Irg1 flox conditional knockout mice along with neutrophil depletion experiments revealed a role for Irg1 in alveolar macrophages and LysM+ myeloid cells in preventing neutrophil-mediated immunopathology and disease. RNA-seq analyses suggest that Irg1 and its production of itaconate temper Mtb-induced inflammatory responses in myeloid cells at the transcriptional level. Thus, Irg1 modulates inflammation to curtail Mtb-induced lung disease. Overall design: Neutrophils were purified from bone marrow of naïve mice by negative selection using magnetic-activated cell sorting beads (Miltenyi). Neutrophil purity (>95%) was assessed by flow cytometry as the percentage of Ly6G+ CD11b+ cells. Neutrophils were cultured in RPMI-1640 supplemented with 1% non-essential amino acids at 37°C, 5% CO2. GFP-Mtb was grown to mid-log phase, washed with PBS, sonicated to disperse clumps, and resuspended in neutrophil culture media. GFP-Mtb then was opsonized prior to infection by mixing with an equal volume of normal mouse sera (Sigma) and incubation at room temperature for 30 min. Neutrophils were mock-infected or infected with opsonized GFP-Mtb at MOI 1 and incubated at 37°C, 5% CO2.
<i>Irg1</i> expression in myeloid cells prevents immunopathology during <i>M. tuberculosis</i> infection.
Specimen part, Cell line, Subject, Time
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