RNAseq on lungs from WT vs claudin 4 KO mice that underwent ventilator-induced lung injury
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ABSTRACT: WT mice and claudin 4 KO mice were exposed to ventilator-induced lung injury (VILI) for 2 hours. We found that in some Cldn4 KO mice, injury was similar to WT, while in others, injury was higher, as assessed by amount of protein leak into broncho-alveolar lavage fluid. We performed RNAseq to find which genes were responsible for higher injury in Cldn4 KO mice.
Project description:WT mice and claudin 4 KO mice were exposed to ventilator-induced lung injury (VILI) for 2 hours. We found that in some Cldn4 KO mice, injury was similar to WT, while in others, injury was higher, as assessed by amount of protein leak into broncho-alveolar lavage fluid. We performed RNAseq to find which genes were responsible for higher injury in Cldn4 KO mice. WT mice and claudin 4 KO mice were exposed to ventilator-induced lung injury (VILI) for 2 hours. RNA were extracted from whole lungs and RNA sequencing was performed. The samples are (all in duplicates): WT no VILI, Cldn4 KO no VILI, WT VILI, Cldn4 KO VILI with similar injury to WT (Cldn4 KOlow), and Cldn4 KO VILI with higher injury than WT (Cldn4 KOhigh)
Project description:Rationale: Using an ortholog candidate gene approach, we previously identified GADD45a (growth arrest and DNA damage-inducible gene 45a) as a potential novel candidate involved in ventilator-induced lung injury (VILI). Objectives: We investigated whether genetically engineered mice with GADD45a deletion were more susceptible to ventilator- or endotoxin (LPS)-induced lung injury. We employed genomic strategies to explore the mechanistic involvement of GADD45a in inflammatory lung injury. Methods: Wild-type C57Bl/6 and GADD45a-/- mice were phenotyped for lung injury following exposure to high tidal volume ventilation (VILI) or intratracheal LPS. Whole lung homogenates were utilized for gene expression studies of ventilated animals and spontaneously breathing controls. To explore the consequences of GADD45a depletion on lung vascular permeability, electrical resistance was measured using human endothelial cells (EC) transfected with small interfering RNA (siRNA) specific for GADD45a or control sequence, or with active Akt1/PKBï¡ cDNA. Results: Mice harboring deletion of GADD45a were modestly susceptible to LPS-induced injury and profoundly susceptible to VILI, demonstrating increased inflammation and increased microvascular permeability. VILI-exposed GADD45a-/- mice manifested striking neutrophilic alveolitis and increased levels of BAL protein, IgG, and inflammatory cytokines. Expression profiling revealed strong dysregulation in the B cell receptor signaling pathway in GADD45a-/- mice, with involvement of several PI3K/Akt signaling components. Akt protein and phospho-Akt were reduced in GADD45a-/- lungs. Further, human EC with reduced GADD45a (siRNA) exhibited potentiated LPS-induced barrier dysfunction, which was attenuated by overexpressing active Akt1. Conclusions: GADD45a, which modulates Akt availability, is a significant participant in modulating vascular permeability and susceptibility to VILI. Experiment Overall Design: 4 experimental groups, each with 3 mouses. Wild type control group, VILI group, GADD-/- group, GADD-/- and VILI group.
Project description:RATIONALE: Mechanical ventilation (MV) is an indispensable therapy for critically ill patients with acute lung injury and the adult respiratory distress syndrome. However, the mechanisms by which conventional MV induces lung injury remain unclear. OBJECTIVES: We hypothesized that disruption of the gene encoding Nrf2, a transcription factor which regulates the induction of several antioxidant enzymes, enhances susceptibility to ventilator-induced lung injury (VILI), while antioxidant supplementation attenuates such effect. METHODS: To test our hypothesis and to examine the relevance of oxidative stress in VILI, here we have assessed lung injury and inflammatory responses in Nrf2-deficient (Nrf2(-/-)) mice and wildtype (Nrf2(+/+)) animals following acute (2 h) injurious model of MV with or without administration of antioxidant. MEASUREMENTS AND MAIN RESULTS: Nrf2(-/-) mice displayed greater levels of lung alveolar and vascular permeability and inflammatory responses to MV as compared to Nrf2(+/+) mice. Nrf2-deficieny enhances the levels of several pro-inflammatory cytokines implicated in the pathogenesis of VILI. We found diminished levels of critical antioxidant enzymes and redox imbalance by MV in the lungs of Nrf2(-/-) mice; however antioxidant supplementation to Nrf2(-/-) mice remarkably attenuated VILI. When subjected to clinically relevant prolong period of MV, Nrf2(-/-) mice displayed greater levels of VILI than Nrf2(+/+) mice. Expression profiling revealed lack of induction of several VILI genes, stress response and solute carrier proteins and phosphatases in Nrf2(-/-) mice. CONCLUSIONS: Collectively, our data demonstrate for the first time a critical role for Nrf2 in VILI, which confers protection against cellular responses induced by MV by modulating oxidative stress. Keywords: stress response; genetically modified mice
Project description:Long non-coding RNAs are closely associated with the regulation of various biological processes and are involved in the pathogenesis of numerous diseases. However, the role of lncRNAs in ventilator-induced lung injury (VILI) has yet to be evaluated. This study aims to evaluate the expression profile and role of lncRNAs and mRNAs in VILI.
Project description:Purpose: Long non-coding RNAs (lncRNAs) have been implicated in the inflammatory response of many diseases; however, their roles in Ventilator-Induced Lung Injury remain unclear. We therefore performed transcriptome profiling of lncRNA and mRNA using RNA-sequencing in lungs collected from mice model of Ventilator-Induced Lung Injury and control groups. Methods: Gene expression was analyzed through RNA sequencing and quantitative RT-PCR. A comprehensive bioinformatics analysis was used to characterize the expression profiles and relevant biological functions and for multiple comparisons among the controls and the injury models at different time points. Results:The mRNA transcript profiling, co-expression network analysis, and functional analysis of altered lncRNAs indicated enrichment in the regulation of immune system/inflammation processes, response to stress, and inflammatory pathways. Conclusions: In summary, our study identified aberrant lncRNA alterations regulated by high-stretch ventilation, and bioinformatics analysis was used to screen the key biological processes and pathways involved in inflammation upon VILI. lncRNA-mediated regulatory patterns might contribute to VILI inflammation.
Project description: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
Project description:RATIONALE: Mechanical ventilation (MV) is an indispensable therapy for critically ill patients with acute lung injury and the adult respiratory distress syndrome. However, the mechanisms by which conventional MV induces lung injury remain unclear. OBJECTIVES: We hypothesized that disruption of the gene encoding Nrf2, a transcription factor which regulates the induction of several antioxidant enzymes, enhances susceptibility to ventilator-induced lung injury (VILI), while antioxidant supplementation attenuates such effect. METHODS: To test our hypothesis and to examine the relevance of oxidative stress in VILI, here we have assessed lung injury and inflammatory responses in Nrf2-deficient (Nrf2(-/-)) mice and wildtype (Nrf2(+/+)) animals following acute (2 h) injurious model of MV with or without administration of antioxidant. MEASUREMENTS AND MAIN RESULTS: Nrf2(-/-) mice displayed greater levels of lung alveolar and vascular permeability and inflammatory responses to MV as compared to Nrf2(+/+) mice. Nrf2-deficieny enhances the levels of several pro-inflammatory cytokines implicated in the pathogenesis of VILI. We found diminished levels of critical antioxidant enzymes and redox imbalance by MV in the lungs of Nrf2(-/-) mice; however antioxidant supplementation to Nrf2(-/-) mice remarkably attenuated VILI. When subjected to clinically relevant prolong period of MV, Nrf2(-/-) mice displayed greater levels of VILI than Nrf2(+/+) mice. Expression profiling revealed lack of induction of several VILI genes, stress response and solute carrier proteins and phosphatases in Nrf2(-/-) mice. CONCLUSIONS: Collectively, our data demonstrate for the first time a critical role for Nrf2 in VILI, which confers protection against cellular responses induced by MV by modulating oxidative stress. Experiment Overall Design: The Nrf2 wildtype (Nrf2+/+) and Nrf2-deficient (Nrf2â/â) CD-1/ICR strains of mice were subjected to mechanical ventilation with high (HVT) amounts of tidal volumes (VT) at 30 ml/kg for 2 hours. The animals subjected to spontaneous ventilation (SpV) for 2 hours were used as controls. Lungs were immediately removed and processed for total RNA isolation using TRIzol reagent (LifeTechnologies, Grand Island, NY). The isolated RNA was applied to Murine Genome 430A GeneChip arrays (Affymetrix, Santa Clara, CA), which contain probes for detecting ~14,500 well-characterized genes and 4371 expressed sequence tags according to standard microarray protocol. Scanned output files were analyzed by using Affymetrix GeneChip Operating Software and were independently normalized to an average intensity of 500.
Project description:We 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. Experiment Overall Design: animals were treated by PBS, rhPBEF (IT administration), VILI (4 hours, 30 ml/kg tidal volume), or both.
Project description:Background: Mechanical ventilation causes ventilator-induced lung injury in animals and humans. Mitogen-activated protein kinases have been implicated in ventilator-induced lung injury though their functional significance remains incomplete. We characterize the role of p38 mitogen-activated protein kinase/ mitogen activated protein kinase kinase-3 and c-Jun-NH2-terminal kinase-1 in ventilator-induced lung injury and investigate novel independent mechanisms contributing to lung injury during mechanical ventilation. Methodology and Principle Findings: C57/BL6 wild-type mice and mice genetically deleted for mitogen-activated protein kinase kinase-3 (mkk-3-/-) or c-Jun-NH2-terminal kinase-1 (jnk1-/-) were ventilated, and lung injury parameters were assessed. We demonstrate that mkk3-/- or jnk1-/- mice displayed significantly reduced inflammatory lung injury and apoptosis relative to wild-type mice. Since jnk1-/- mice were highly resistant to ventilator-induced lung injury, we performed comprehensive gene expression profiling of ventilated wild-type or jnk1-/- mice to identify novel candidate genes which may play critical roles in the pathogenesis of ventilator-induced lung injury. Microarray analysis revealed many novel genes differentially expressed by ventilation including matrix metalloproteinase-8 (MMP8) and GADD45a. Functional characterization of MMP8 revealed that mmp8-/- mice were sensitized to ventilator-induced lung injury with increased lung vascular permeability. Conclusions: We demonstrate that mitogen-activated protein kinase pathways mediate inflammatory lung injury during ventilator-induced lung injury. C-Jun-NH2-terminal kinase was also involved in alveolo-capillary leakage and edema formation, whereas MMP8 inhibited alveolo-capillary protein leakage. Keywords: response to injury, genetically modified mouse
Project description:We 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. We used microarrays to detail the global programme of gene expression induced by rhPBEF treatment and VALI. Experiment Overall Design: animals were treated by PBS, rhPBEF (IT administration), VILI (4 hours, 30 ml/kg tidal volume), or both.