We explored the mechanistic involvement of the growth arrest and DNA damageinducible gene, GADD45a, in LPS- and ventilator-induced inflammatory lung injury (VILI). Multiple biochemical and genomic parameters of inflammatory lung injury indicated GADD45a-/- mice to be modestly susceptible to intratracheal LPS-induced lung injury and profoundly susceptible to high tidal volume ventilation-induced lung injury (VILI) with increases in microvascular permeability and levels of inflammatory cytokines in bronchoalveolar lavage. Expression profiling of lung tissues from GADD45a-/- mice revealed strong dysregulation in the B cell receptor signaling pathway suggesting involvement of PI3 kinase/Akt signaling components while the wild type controls depicted no observable changes. Western blot analyses of lung homogenates confirmed ~50% reduction in Akt protein levels in GADD45a-/- mice accompanied by marked increases in Akt ubiquitination. Electrical resistance measurements across human lung endothelial cell monolayers with either reduced GADD45a or Akt expression (siRNAs) revealed significant potentiation of LPS-induced human lung endothelial barrier dysfunction which was attenuated by overexpression of a constitutively active Akt1 transgene. These studies validate GADD45a as a novel candidate gene in inflammatory lung injury and a significant participant in vascular barrier regulation via effects on Akt-mediated endothelial signaling
GADD45a is a novel candidate gene in inflammatory lung injury via influences on Akt signaling.
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View SamplesWe sought to confirm the genetic influence in the development of Ventilation-Associated Lung Injury (VALI) and, in the process, identify potential candidate genes involved in the disease by integrating differential gene expression profiling on rat lungs to a traditional strain survey analysis of the parental rat strains, VALI-sensitive Brown Norway rats versus VALI-resistant Dahl Salt Sensitive rats, comparing control (under room air ventilation) versus under high tidal volume (HTV) ventilation.
Use of consomic rats for genomic insights into ventilator-associated lung injury.
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View SamplesWe have previously demonstrated that pre-B-cell colony enhancing factor (PBEF) ais a biomarker in sepsis and sepsis-induced acute lung injury (ALI) with genetic variants conferring ALI susceptibility118. In the current study, we explored the mechanistic participation of PBEF in ALI and ventilator-induced associated lung injury (VIALI). Initial in vitro studies and demonstrated rhPBEF aas a direct rat neutrophil chemotactic factor in vitro producing marked in vivo increases in BAL leukocytes (PMNs) in vivo following (intratracheal injection (,IT) in C57B6 mice. These latter changes were accompanied by increased BAL levels of the PMN chemoattractants (, KC and MIP2), and modest changes in lung vascular and but were not associated with significant increasesin alveolar permeability. We next explored the potential synergism between rhPBEF administration (IT) and a mechanical ventilation model of modest VILI lung injury (4 hours, 30 ml/kg tidal volume). We and observed dramatic synergistic increases in BAL PMNs, and both BAL protein and cytokine levels (IL-6, TNF-?, KC). Gene expression profiling Microarray analysis further supported a major role for PBEF in the induction of gene modules associated with ALI and VALI (NFkB pathway, leukocyte extravasation, apoptosis, toll receptor signaling). Finally, we exposed wild type and heterozygous PBEF+/- mice (targeted deletion of a single PBEF allele deletion) to a model of severe VILImechanical ventilation-induced lung injury (4 hours, 40 ml/kg tidal volume). PBEF+/- mice were significantly protected from VIALI-associated increases in BAL protein and BAL IL-6 levels and exhibited significantly reduced expression of ALI-associated gene expression modules. Together, these results indicate that PBEF is a key inflammatory mediator intimately involved in both the development and severity of ventilator-induced ALI.
Essential role of pre-B-cell colony enhancing factor in ventilator-induced lung injury.
No sample metadata fields
View SamplesWe have previously demonstrated that pre-B-cell colony enhancing factor (PBEF) ais a biomarker in sepsis and sepsis-induced acute lung injury (ALI) with genetic variants conferring ALI susceptibility118. In the current study, we explored the mechanistic participation of PBEF in ALI and ventilator-induced associated lung injury (VIALI). Initial in vitro studies and demonstrated rhPBEF aas a direct rat neutrophil chemotactic factor in vitro producing marked in vivo increases in BAL leukocytes (PMNs) in vivo following (intratracheal injection (,IT) in C57B6 mice. These latter changes were accompanied by increased BAL levels of the PMN chemoattractants (, KC and MIP2), and modest changes in lung vascular and but were not associated with significant increasesin alveolar permeability. We next explored the potential synergism between rhPBEF administration (IT) and a mechanical ventilation model of modest VILI lung injury (4 hours, 30 ml/kg tidal volume). We and observed dramatic synergistic increases in BAL PMNs, and both BAL protein and cytokine levels (IL-6, TNF-?, KC). Gene expression profiling Microarray analysis further supported a major role for PBEF in the induction of gene modules associated with ALI and VALI (NFkB pathway, leukocyte extravasation, apoptosis, toll receptor signaling). Finally, we exposed wild type and heterozygous PBEF+/- mice (targeted deletion of a single PBEF allele deletion) to a model of severe VILImechanical ventilation-induced lung injury (4 hours, 40 ml/kg tidal volume). PBEF+/- mice were significantly protected from VIALI-associated increases in BAL protein and BAL IL-6 levels and exhibited significantly reduced expression of ALI-associated gene expression modules. Together, these results indicate that PBEF is a key inflammatory mediator intimately involved in both the development and severity of ventilator-induced ALI.
Essential role of pre-B-cell colony enhancing factor in ventilator-induced lung injury.
No sample metadata fields
View SamplesThe immune system relies on the plasticity of its components to produce appropriate responses to frequent environmental challenges. Dendritic cells (DCs) are critical initiators of innate immunity and orchestrate the later and more specific adaptive immunity. The generation of diversity in transcriptional programs is central for effective immune responses. Alternative splicing is widely considered a key generator of transcriptional and proteomic complexity, but its role has been rarely addressed systematically in immune cells. Here we used splicing-sensitive arrays to assess genome-wide gene- and exon-level expression profiles in human DCs in response to a bacterial challenge. We find widespread alternative splicing events and splicing factor transcriptional signatures induced by an E. coli challenge to human DCs. Alternative splicing acts in concert with transcriptional modulation, but these two mechanisms of gene regulation affect primarily distinct functional gene groups. Alternative splicing is likely to have an important role in DC immunobiology because it affects genes known to be involved in DC development, endocytosis, antigen presentation and cell cycle arrest
Genome-wide analysis of alternative splicing during dendritic cell response to a bacterial challenge.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide screen reveals APC-associated RNAs enriched in cell protrusions.
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View SamplesThe goal of the study was to identify on a genome-wide scale RNAs that are enriched at the leading edge of migrating cells. For this, we employed a fractionation method in which cells are plated on a microporous filter whose bottom side only is coated with fibronectin. The cells thus polarize and extend pseudopodial protrusions towards the bottom surface. These protruding pseudopodia can then be physically isolated from the bottom surface of the filter and their contents compared with the remaining cell bodies, which are isolated from the upper surface of the filter.
Genome-wide screen reveals APC-associated RNAs enriched in cell protrusions.
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View SamplesThe goal of the study was to identify on a genome-wide scale RNAs that are enriched at the leading edge of migrating cells. For this, we employed a fractionation method in which serum-starved cells are first plated and allowed to spread on a microporous filter. Addition of LPA at the bottom side of the filter induces the cells to polarize and extend pseudopodial protrusions. These protruding pseudopodia can then be physically isolated from the bottom surface of the filter and their contents compared with the remaining cell bodies, which are isolated from the upper surface of the filter.
Genome-wide screen reveals APC-associated RNAs enriched in cell protrusions.
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View SamplesPURPOSE To identify retinal pigment epithelial (RPE)/choroid genes and their relevant expression pathways affected by intravitreal injections of dexamethasone and triamcinolone acetonide in mice at clinically relevant time points for patient care. METHODS Differential gene expression of over 34,000 well-characterized mouse genes, in the RPE/choroid of 6 week old C57BL/6J mice were analyzed after intravitreal steroid injections at 1 week and 1 month post injection, using Affymetrix Mouse Genome 430 2.0 microarrays. The data were analyzed using GeneSpringGX12.5 and Ingenuity Pathway Analysis (IPA) microarray analysis software for biologically relevant changes. RESULTS Both triamcinolone and dexamethasone caused differential activation of genes involved in Circadian Rhythm Signaling pathway at both time points tested. Triamcinolone (TAA) uniquely induced significant changes in gene expression in Calcium Signaling (1 week) and Glutamate Signaling pathways (1month). In contrast, Dexamethasone (Dex) affected the GABA Receptor Signaling (1 week) and Serotonin Receptor Signaling (1month) pathways. CONCLUSIONS Understanding how intraocular steroids affect the gene expression of RPE/choroid is clinically relevant. This in vivo study has elucidated several genes and pathways that are potentially altering the circadian rhythms and several other neurotransmitter pathways in RPE/choroid cells during intravitreal steroid injections, which likely has consequences in the dysregulation of RPE function and neurodegeneration of the retina.
Comparison of In Vivo Gene Expression Profiling of RPE/Choroid following Intravitreal Injection of Dexamethasone and Triamcinolone Acetonide.
Sex, Specimen part, Treatment
View SamplesHnRNPLL was identified as a critical regulator of CD45 alternative splicing in a lentiviral shRNA screen. RNAi-mediated depletion of hnRNPLL eliminated the activation-induced induced transition from the CD45RA to the CD45RO isoform. HnRNPLL is induced during the process of T cell activation, raising the possibility that it regulates a broad program of alternative splicing in activated T cells. To test this possibility and to identify additional potential targets of hnRNPLL, we performed exon array analysis on RNA isolated from five cellular conditions: 1) activated peripheral CD4+ T cells, 2) peripheral CD4+ T cells infected with a control shRNA directed against GFP, 3) peripheral CD4+ T infected with an shRNA directed against hnRNPLL, 4) nave cord blood CD4+ T cells, and 5) cord blood CD4+ T cells that had been activated with anti-CD3 and anti-CD28 for 24 hours. The RNA was hybridized to Affymetrix human exon arrays and the hybridization signals were analyzed with XRAYTM software (Biotique). Using stringent filters for non-expressed probesets, we identified 132 genes that showed significant alternative exon usage (p<0.01) in response to hnRNPLL knockdown, but not in response to shGFP infection. Of these 132 genes, 36 also showed significant alternative exon usage in response to activation of cord blood cells, which results in an approximate 5-fold increase in hnRNPLL expression. We thus conclude that induction of hnRNPLL represents a mechanism by which cells can rapidly shift their transcriptomes during the process of T cell activation.
Regulation of CD45 alternative splicing by heterogeneous ribonucleoprotein, hnRNPLL.
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