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:To study the effects of previous exposure to mechanical ventilation may modify the development of Ventilator-induced lung injury, preconditioning was induced by low-pressure ventilation for 90 minutes. After 1 week, intact (sham) and preconditioned mice were sacrificed, the lungs extracted and gene expression measured in order to identify differences responsible for the observed tolerance to ventilator-induced lung injury observed in preconditioned animals. 6 samples were analyzed, from 3 intact (sham) and 3 preconditioned CD1 mice.
Project description:To study the effects of previous exposure to mechanical ventilation may modify the development of Ventilator-induced lung injury, preconditioning was induced by low-pressure ventilation for 90 minutes. After 1 week, intact (sham) and preconditioned mice were sacrificed, the lungs extracted and gene expression measured in order to identify differences responsible for the observed tolerance to ventilator-induced lung injury observed in preconditioned animals.
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:This study was undertaken to examine differential gene expression across the whole genome during short-term ventilator-induced lung injury in mice, a commonly used model of acute lung injury, as compared with spontaneous ventilation. Keywords: Disease state analysis
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