Project description:Protective roles of Nrf2, a key transcription factor for antioxidant and defense genes, have been determined in oxidative lung injury, and health benefits of Nrf2 agonists including sulforaphane have been demonstrated. The current study was designed to investigate the effect of sulforaphane on model acute lung injury and sulforaphane-mediated transcriptome changes in mouse lungs. Adult mice genetically deficient in Nrf2 (Nrf2-/-) and wild-type controls (Nrf2+/+, ICR) received oral sulforaphane (9 mmol/daily) or vehicle before (-5, -3, -1 days) hyperoxia or air exposure (3 days), and lung injury and gene expression changes were assessed. Sulforaphane significantly reduced hyperoxia-induced airway injury, inflammation, and mucus hypersecretion in Nrf2+/+ mice while relatively marginal treatment effect was found in Nrf2-/- mice. Sulforaphane significantly altered expression of lung genes associated with oxidative phosphorylation and mitochondrial dysfunction (Atp2a2, Cox7a1, Ndufa1) basally and cell function/cycle and protein metabolism (Actr1a, Wasf2, Ccne1, Gtpbp4) after hyperoxia in Nrf2+/+ mice. Nrf2-dependently modulated lung genes by sulforaphane and hyperoxia were associated with tissue development and hereditary disorders (Slc25a3, Pccb, Psmc3ip). Results demonstrate preventive roles of sulforaphane against oxidant lung injury in mice, and reveal potential downstream mechanisms. Our observations also suggest Nrf2-independent mechanisms of sulforaphane in prevention of acute lung injury.
Project description:Oxygen therapy is essential for cure critically patients in ICU, but hyperoxia can cause damage to many organs, including the lungs, leading to Hyperoxia Acute Lung Injury (HALI), a mild type of acute respiratory distress syndrome (ARDS). However, the comprehensive pathogenesis and regulation mechanisms underlying the development of HALI remain unclear. In this study, we conducted a mouse model with hyperoxia treatment and sequenced the gene expression pattern of HALI-mice and relative control (RNA-seq).
Project description:Aeromedical evacuation (AE) is an important tool for transit of injured patients, but both the hypobaria and hyperoxia associated with AE may contribute to secondary injury. We aimed to examine the effects of these acute exposures on gene expression while avoiding the inflammatory storm that would result from injury and potentially mask underlying causes of AE-related secondary injury. We exposed healthy, young male rats to different levels of hypobaria (4000 ft or 8000 ft eqiv.) and/or hyperoxia (100% oxygen) for different durations of time (5 or 10 h). We collected heart, lung, brain (hippocampus), and blood tissue samples, processed them for RNA, and performed microarray analysis on the samples.
Project description:Background: Obesity has become a worldwide concern. Acute respiratory distress syndrome (ARDS) comprises 10.4% of total intensive care unit admissions and is associated with very high mortality. ARDS incidence is increased in obese patients. Exposure of rodents to hyperoxia mimics many of the clinical and pathologic features observed in patients with ARDS. The aim of this study was to determine the impact of high fat diet-induced obesity on the susceptibility to hyperoxic acute lung injury in mice. Methods: Male C57BL/6 mice received 60% fat versus ingredient matched 10% fat diet. Mice were exposed to >95% oxygen to induce lung damage. RNA was isolated from lung homogenates and by comparing RNA sequencing results with mouse Mitocarta, an inventory of genes encoding proteins with mitochondrial localization, we identified fatty acid synthase (FASN), an enzyme catalyzing de novo fatty acid synthesis, as one of the mitochondrial genes significantly changed with diet and with hyperoxia. We generated mice deficient in FASN in alveolar epithelial cells by using a tamoxifen inducible Cre recombinase construct (FASNflox/flox SPC Cre+/-) and subjected them to hyperoxia and high fat diet. Results: Mice receiving 60% fat diet had significantly higher weight, serum cholesterol and fasting glucose. High fat diet mice had significantly reduced survival and increased lung damage, as assessed by BAL protein and LDH, histology and TUNEL staining. By RNA sequencing of lung homogenates we identified FASN as one of the mitochondrial genes significantly reduced in mice receiving 60% compared to 10% fat diet and further reduced with hyperoxia. We confirmed that FASN protein levels in the lung of high fat diet mice were lower by immunoblotting and immunohistochemistry. After 48 hours of hyperoxia FASNflox/flox SPC Cre+/- mice displayed increased levels of BAL protein and LDH and more severe histologic lung injury. FASNflox/flox SPC Cre+/- mice remained more prone to lung injury after hyperoxic exposure even when they received 60% fat diet. Conclusions: These results demonstrate that obesity increases the severity of hyperoxia induced acute lung injury in mice by altering FASN levels in the lung of high fat diet fed rodents. To our knowledge, this is the first study to show that high fat diet leads to altered FASN expression in the lung and that both high fat diet and reduced FASN in alveolar epithelial cells lead to increased lung injury under hyperoxic conditions.
Project description:Sphingosine Kinase-1 knock out protects against hyperoxic lung injury One day old Wild type (WT) control and Sphingosine Kinase-1 knock out (SphK-1 KO)pups exposed to room air (RA) or hyperoxia (HO). Microarray based profiling of lung tissue after 7 days of hyperoxia of 75%
Project description:This study is to examine the transcriptome of mononuclear cell populations in the neonatal lung. We investigated how acute hyperoxia-induced lung injury changes gene expression within these mononuclear populations: dendritic cells, interstitial monocytes/macrophages, and alveolar macrophages.
Project description:Hyperoxia is known to cause cerebral white matter injury in preterm infants. Preterm birth is also associated with sudden hormonal changes which includes drop of estrogen level and increased postnatal production of fetal zone steroids (FZS). Therefore, we investigated the effect of hyperoxia (80% O2) and the subsequent administration of FZS on the proteins of immature oligodendrocytes using the OLN93 (rat-derived OPC) cell line as an experimental model. We demonstrate that hyperoxia has a negative effect on migration and associated signalling pathways, and that FZS and estrogen have distinct effects on these alterations.
Project description:We have previously demonstrated that deletion of the Cebpa gene in the developing fetal mouse lung caused death soon after birth from the failure of lung maturation. Many of the transcriptional pathways regulating morphogenesis of the fetal lung are induced postnatally and mediate repair of the injured lung. We hypothesized that C/EBPa plays a role in protection of the alveolar epithelium following hyperoxia injury of the mature lung. Transgenic Cebpa∆/∆ mice in which Cebpa was conditionally deleted from Clara cells (from early gestation) and type II cells (from near-term) were developed. Cebpa∆/∆ mice grow normally without any pulmonary abnormalities. Cebpa∆/∆ mice were highly susceptible to hyperoxia. Cebpa∆/∆ mice died within 4d after hyperoxia associated with severe lung inflammation and altered surfactant components at a time when all control mice survived. Microarrays were analyzed on isolated type II cells at an early stage (24h) of hyperoxia exposure to detect the primary genes influenced by deletion of Cebpa. The associated network analysis revealed the reduced expression of key genes related to surfactant lipid and protein homeostasis, such as Srebf, Scap, Lpcat1, Abca3, Sftpb, and Napsa. Genes for the cell signaling, immune response, and protective antioxidants, including GSH and Vnn-1,3, were decreased in the Cebpa∆/∆ mice lung. C/EBPa did not play a critical role in postnatal pulmonary function under normal conditions. In contrast, in the absence of C/EBPa, exposure to hyperoxia caused respiratory failure, supporting the concept that C/EBPa plays an important role in enhancing epithelial cell survival, surfactant lipid homeostasis, and maturation of SP-B from pro-SP-B.