Traumatic spinal cord injury (SCI) initiates a complex series of pathophysiological secondary responses that lead to tissue loss and functional deficits.This study represents a comprehensive database of temporal changes in gene expression that underlie the secondary injury response that occurs in a well-defined mouse model of contusion injury.
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View SamplesWith advances in supportive therapy in the last two decades, mortality rates from ALI/ARDS have improved somewhat, but remain around 30 to 40% with significant morbidity in survivors. Several promising treatments are in various stages of evaluation, but many have failed to prove beneficial in large randomized clinical trials (RCT). The first definitive step forward in ALI therapeutics occurred recently as a result of a large RCT demonstrating a mortality decrease from 40 to 31% with the use of low-volume ventilation strategies. From this, it is clear that the opportunity for successful intervention in ALI exists. However, therapeutic advances remain frustrated by the lack of complete understanding of ALI pathophysiology. This stresses the importance of integrating basic and clinical research of the molecular pathogenesis of this disease. The conclusions of a recent National Heart, Lung, and Blood Institute (NHLBI) Working Group on ALI support this type of research as a priority for future investigations of ALI. One of the areas of research given priority by this ALI Working Group is the issue of ALI severity progression and the role of cells of innate immunity in this process. Currently, the processes that determine which ALI patients progress to ARDS and which do not are unclear. As with many phenotype differences, there is most likely a genetic component involved. The basis for this has been demonstrated. For example, a surfactant protein B (SP-B) polymorphism appears to increase a patients risk of developing ALI from pneumonia. Additionally, a polymorphism in the promoter region of the gene for interleukin-6 (IL-6) has been associated with a poor prognosis in patients with ARDS. Understanding the intracellular processes of these genes and the cells expressing them in ALI progression could lead to the identification of molecular markers of ALI severity and eventually to the development of targeted therapies. An examination of genetically uniform animals will provide a clearer insight into the interaction between immune cells in ALI progression as well as guide future human experiments.
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Specimen part
View SamplesNeurofibromatosis Type 1 (NF1) patients develop benign neurofibromas and malignant peripheral nerve sheath tumors (MPNST). These incurable peripheral nerve tumors result from loss of NF1 tumor suppressor gene function, causing hyperactive Ras signaling. Activated Ras controls numerous downstream effectors, but specific pathways mediating effects of hyperactive Ras in NF1 tumors are unknown. Cross-species transcriptome analyses of mouse and human neurofibromas and MPNSTs identified global negative feedback of genes that regulate Ras-Raf- MEK- extracellular signal-regulated protein kinase (ERK) signaling in both species. Nonetheless, activation of ERK was sustained in mouse and human neurofibromas and MPNST. PD0325901, a highly selective pharmacological inhibitor of MEK, was used to test whether sustained Ras-Raf-MEK-ERK signaling contributes to neurofibroma growth in the Nf1fl/fl;Dhh-cre mouse model or in NF1 patient MPNST cell xenografts. PD0325901 treatment reduced aberrantly proliferating cells in neurofibroma and MPNST, prolonged survival of mice implanted with human MPNST cells, and shrank neurofibromas in >80% of mice tested. PD0325901 also caused effects on tumor vasculature. Our data demonstrate that deregulated Ras/ERK signaling is critical for the growth of NF1 peripheral nerve tumors and provide strong rationale for testing MEK inhibitors in NF1 clinical trials.
MEK inhibition exhibits efficacy in human and mouse neurofibromatosis tumors.
Specimen part
View SamplesGaucher Disease (GD) is caused by defective glucocerebrosidase (GCase) activity and the consequent accumulation of its substrate, glucosylceramide (GC). This excess of accumulation of GC leads to broad functional impairments in multiple organs, but the pathogenic pathways leading to lipid laden macrophages (Gaucher cells) in visceral organs and their abnormal function is obscure. To understand the molecular pathogenesis of GD, developmental global gene expression was conducted by microarray analyses of total mRNAs from lung and liver of two distinct GCase point-mutated mice (V394L/V394L and D409V/null) and genetic background matched wild-type controls. INFg regulated pro-inflammatory and IL-4 regulated anti-inflammatory cytokine/mediator network were constructed in the lung and liver of GCase mutant mice. Progressive alterations of the INFg and IL-4 pathways were similar, but to different degrees, in visceral tissues from the two different GCase mutated mice. These analyses implicate IFNg regulated pro-inflammatory and IL-4 regulated anti-inflammatory networks in the differential pathophysiological progression.
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Age, Specimen part
View SamplesThe beta1-adrenergic receptor (beta1AR; ADRB1) polymorphism Arg 389Gly is located in an intracellular loop and is associated with distinct human and mouse cardiovascular phenotypes. To test the hypothesis that beta1-Arg389 and beta1-Gly389 alleles could differentially couple to pathways beyond that of classic Gs-adenylyl cyclase (AC)/cAMP signaling, we performed comparative gene expression profile analyses on hearts from wildtype and transgenic mice that expressed either human beta1-Arg389 and beta1-Gly389 receptors, or AC5 adenyl cyclase, sampling at an early age and stage, prior to the onset of pathologic features. We observed substantial overlap of dysregulated genes across all three transgenic heart models, consistent with a shared coupling to cAMP-dependent regulation of cardiac processes and adaptive responses. All three models up-regulated genes associated with RNA metabolism and translation, and down-regulated genes associated with mitochondria and energy metabolism, consistent with cAMP-driven increase in cardiac contractility, protein synthesis, and compensatory down-regulation of mitochondrial energy production. Both beta1AR transgenics activated additional genes associated with kinase-dependent pathways, and uniquely, beta1-Arg389 hearts caused up-regulation of genes associated with inflammation, programmed cell death, and extracellular matrix. These results substantially expand the scope of 7-transmembrane domain receptor signaling propagation beyond known cognate G-protein couplings. Moreover, they implicate alterations of a repertoire of processes evoked by a single amino acid variation in the cardiac beta1AR that might be exploited for genotype-specific heart failure diagnostics and therapeutics.
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View SamplesDuring mammalian kidney development, mesenchymal nephron progenitors (cap mesenchyme) differentiate into the epithelial cells that go on to form the nephron. Although differentiation of nephron progenitors is triggered by activation of Wnt/b-catenin signaling, constitutive activation of Wnt/b-catenin signaling blocks epithelialization of nephron progenitors. Full epithelialization of nephron progenitors requires transient activation of Wnt/b-catenin signaling. We performed transcriptional profiling of nephron progenitors responding to constitutive or transient activation of Wnt/b-catenin signaling.
Six2 and Wnt regulate self-renewal and commitment of nephron progenitors through shared gene regulatory networks.
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View SamplesMacrophage activation syndrome (MAS) is a life-threatening complication of systemic juvenile idiopathic arthritis (SJIA), and increasingly reported in association with severe lung disease (SJIA-LD) of unknown etiology. This study mechanistically defines the novel observation of pulmonary inflammation in the TLR9 mouse model of MAS that recapitulate key features of SJIA-LD, including IFNg activation. In acute MAS, lungs exhibit a mild but diffuse lymphocyte-predominant perivascular, interstitial inflammation with elevated IFNg, IFN-induced chemokines, and alveolar macrophage (AMf) expression of IFNg-induced genes. However, MAS resolution demonstrated AMf expansion and increased interstitial inflammation. AMf microarrays confirmed IFNg-induced proinflammatory polarization during acute MAS, which switches towards anti-inflammatory phenotype during MAS resolution. Interestingly, recurrent MAS increased alveolar inflammation, and reset polarization towards a pro-inflammatory state. Furthermore, in mice bearing macrophages insensitive to IFNg, both systemic feature of MAS and pulmonary inflammation were markedly attenuated. These findings demonstrate experimental MAS induces IFNg-driven pulmonary inflammation, and define this system for further study of and treatment validation in SJIA-LD.
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Age, Specimen part, Genotype, Treatment
View SamplesNormal erythropoiesis requires a critical balance between proapoptotic and antipaoptotic pathways. Bcl-xl, an antiapoptotic protein is induced at end-stages of differentiation of erythroid precursors in response to erythropoietin. The details of the proapoptotic pathway and the critical proapoptotic proteins inhibited by Bcl-xl in erythropoiesis are not well understood. We employed gene targeting to ablate Nix, a proapoptotic BH3-domain only Bcl2 family protein, which is known to be transcriptionally induced during erythropoiesis. Nix null mice exhibited reticulocytosis and thrombocytosis in the peripheral blood; and profound splenomegaly with erythroblastosis in the spleen and bone marrow despite normal erythropoietin levels and blood oxygen tension. In vivo apoptosis was diminished in erythroblast precursors from Nix null spleens. To define the molecular consequences of Nix ablation on apoptosis and erythropoiesis, we conducted a detailed comparative analysis of gene expression in spleens from 8 week old Nix null mice and wild type controls. Of 45,101 genes analyzed, 514 were significantly upregulated and 386 down-regulated in Nix-/- splenocytes. Functional cluster analysis delineated the ten most highly regulated gene sets, revealing increased levels of cell cycle and erythroid genes, with decreased levels of cell death and B-cell genes.
Unrestrained erythroblast development in Nix-/- mice reveals a mechanism for apoptotic modulation of erythropoiesis.
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View SamplesE12.5 AV cushion and E17.5 AV valve from wild-type FVB/N mice and in vitro cultured MC3T3 cells
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View SamplesBackground: Lung function is dependent upon the precise regulation of the synthesis, storage, and catabolism of tissue and alveolar lipids.
Activation of sterol-response element-binding proteins (SREBP) in alveolar type II cells enhances lipogenesis causing pulmonary lipotoxicity.
Specimen part
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