Project description:Ozone is a highly toxic air pollutant and global health concern. Mechanisms of genetic susceptibility to ozone-induced lung inflammation are not completely understood. We hypothesized Notch3 and Notch4 are important determinants of susceptibility to ozone-induced lung inflammation. Wild type (WT), Notch3 (Notch3-/-) and Notch4 (Notch4-/-) knockout mice were exposed to ozone (0.3 ppm) or filtered air for 6-72 hours. Ozone increased bronchoalveolar lavage fluid (BALF) protein, a marker of lung permeability, in all genotypes, but significantly greater concentrations were found in Notch4-/- compared to WT and Notch3-/-. Significantly greater mean numbers of BALF neutrophils were found in Notch3-/- and Notch4-/- mice compared to WT mice after ozone. Expression of whole lung Tnf was significantly increased after ozone in all genotypes, and was significantly greater in Notch3-/- mice compared to WT. Statistical analyses of the transcriptome identified differentially expressed gene networks between WT and knockout mice basally and after ozone, and included Trim30, a member of the inflammasome pathway, and Traf6, an inflammatory signaling member. These novel findings are consistent with Notch3 and Notch4 as susceptibility genes for ozone-induced lung injury, and suggest that Notch receptors protect against innate immune inflammation.
Project description:Ozone is a highly toxic air pollutant and global health concern. Mechanisms of genetic susceptibility to ozone-induced lung inflammation are not completely understood. We hypothesized Notch3 and Notch4 are important determinants of susceptibility to ozone-induced lung inflammation. Wild type (WT), Notch3 (Notch3-/-) and Notch4 (Notch4-/-) knockout mice were exposed to ozone (0.3 ppm) or filtered air for 6-72 hours. Ozone increased bronchoalveolar lavage fluid (BALF) protein, a marker of lung permeability, in all genotypes, but significantly greater concentrations were found in Notch4-/- compared to WT and Notch3-/-. Significantly greater mean numbers of BALF neutrophils were found in Notch3-/- and Notch4-/- mice compared to WT mice after ozone. Expression of whole lung Tnf was significantly increased after ozone in all genotypes, and was significantly greater in Notch3-/- mice compared to WT. Statistical analyses of the transcriptome identified differentially expressed gene networks between WT and knockout mice basally and after ozone, and included Trim30, a member of the inflammasome pathway, and Traf6, an inflammatory signaling member. These novel findings are consistent with Notch3 and Notch4 as susceptibility genes for ozone-induced lung injury, and suggest that Notch receptors protect against innate immune inflammation. Wild-type, Notch3 knockout, and Notch4 knockout mice at 7-13 weeks of age were exposed continuously to air or 0.3 ppm ozone for 6, 24, or 48 hours. Three biological replicates from individual animals were included in each exposure group from each genotype and samples hybridized to the GeneChip Mouse Genome 430 2.0 array (Affymetrix).
Project description:Fish oil, olive oil, and coconut oil dietary supplementation have several cardioprotective benefits, but it is not established if they can protect against air pollution-induced adverse effects. We hypothesized that these dietary supplements would attenuate ozone-induced systemic and pulmonary effects. Male Wistar Kyoto rats were fed either a normal diet, or a diet enriched with fish, olive, or coconut oil starting at 4 weeks of age for 8 weeks. Animals were then exposed to air or ozone (0.8 ppm), 4h/day for 2 consecutive days. The fish oil diet completely abolished phenylephrine-induced vasoconstriction that was increased following ozone exposure in the animals fed all other diets. Only the fish oil diet increased baseline levels of bronchoalveolar lavage fluid (BALF) markers of lung injury and inflammation. Ozone-induced pulmonary injury/inflammation were comparable in rats on normal, coconut oil, and olive oil diets with altered expression of markers in animals fed the fish oil diet. Fish oil, regardless of exposure, led to enlarged, foamy macrophages in the BALF that coincided with decreased mRNA expression of cholesterol transporters, cholesterol receptors, and nuclear receptors in the lung. Serum miRNA profile was assessed using small RNA-sequencing in normal and fish oil groups and demonstrated marked depletion of a variety of miRNAs, several of which were of splenic origin. No ozone-specific changes were noted. Collectively, these data indicate that while fish oil offered protection from ozone-induced aortic vasoconstriction, it increased pulmonary injury/inflammation and impaired lipid transport mechanisms resulting in foamy macrophage accumulation, demonstrating the need to be cognizant of potential off-target pulmonary effects that might offset the overall benefit of this vasoprotective dietary supplement.
Project description:Inhalation of the amibient air polution ozone causes lung inflammation and can suppress host defense mechanisms, including impairing macrophage phagocytosis. Ozone reacts with cholesterol in the lung to form oxysterols, like secosterol A and secosterol B, which can form covalent adducts on cellular proteins. How oxysterol-protein adduction modifies the function of lung macrophages is unknown. Herein, we used a preoteomic screen to identify lung macrophage proteins that fomr adducts with ozone-derived oxysterols. Analysis show that the phagocytic receptor CD206 and CD64 formed adducts with secosterol A. Adduction of these receptors with ozone-derived oxysterols impaired ligand binding and corresponded with reduced macrophage phagocytosis. This work suggests a novle mechanism for the suppression of macrophage phagocytosis following ozone exposure through the generation of oxysterols and the formation of oxysterol-protein adducts on phagocytic receptors.
Project description:Ozone is a common pollutant and a potent oxidant in industrialized nations. The mechanisms of ozone-induced lung injury and differential susceptibility are not fully understood. Ozone-induced lung inflammation is mediated, in part, by the innate immune system. We hypothesized that mannose binding lectin (MBL), which has a central role in the activation of the complement pathway of innate immunity, is a necessary component of the pro-inflammatory events caused by ozone-mediated activation of the innate immune system. Wild-type (Mbl+/+) and MBL deficient (Mbl-/-) mice were exposed to ozone (0.3 ppm) for 24, 48, and 72 hours, and bronchoalveolar lavage fluid (BALF) was examined for inflammatory markers. Compared to Mbl+/+ mice, significantly greater mean BALF eosinophils, neutrophils and neutrophil attractants CXCL2 (MIP-2) and CXCL5 (LIX) were found in Mbl-/- mice exposed to ozone. Using genome-wide mRNA microarray analyses, we identified significant differences in expression response profiles and networks at baseline (e.g. NRF2 mediated oxidative stress response) and after exposure (e.g. humoral immune response) between Mbl+/+ and Mbl-/- mice. The microarray data were further analyzed using a pattern recognition analysis for Extracting Patterns and Identifying co-expressed Genes (EPIG), and discovered several informative differential response patterns and subsequent gene sets, including antimicrobial response and inflammatory response. These novel findings demonstrate that targeted deletion of Mbl caused differential expression of inflammation-related gene sets basally and after exposure to ozone, and significantly reduced pulmonary inflammation thus indicating an important innate immunomodulatory role of the gene in this model.
Project description:Radiation-induced lung injury is a common late side-effect of thoracic radiotherapy. The inflammatory microenvironment plays a key role in this process. Endothelial cells are the goalkeeper of inflammation. Endothelial dysfunction following leukocytes infiltrated is a prominent feature in the pathogenesis of radiation-induced lung injury. Tyrosine phosphatase Shp2 is a key regulator of endothelial functions and inflammation. Here, we established a clinical-mimicking mouse model of radiation-induced lung injury and found that Shp2 activity was elevated in endothelium after injury. Mice with endothelium-specific Shp2 deletion showed relieved collagen deposition along with disrupted radiation-induced Jag1 expression in the endothelium. Furthermore, endothelium-derived Jag1 activated the alternative activation of macrophages in vitro and in vivo by paracrine Notch signaling. Consistently, Notch pathway was significant activated by chest irradiation in the peripheral blood leukocytes of cancer patients. Collectively, this is the first demonstration of radiation-induced lung injury regulation by endothelial Shp2. Shp2 participates in the radiation-induced endothelial dysfunction and subsequently inflammatory microenvironment producing.
Project description:Ozone-induced lung injury/inflammation and pulmonary/hypothalamus gene expression are diminished in adrenalectomized (ADREX) rats. Acute ozone exposure induces metabolic alterations concomitant with increases in epinephrine and corticosterone. We hypothesized that adrenal hormones are responsible for observed hepatic ozone effects, and in ADREX rats, these changes would be diminished. Five-seven days after sham or ADREX surgeries, male Wistar-Kyoto rats were exposed to air or 0.8-ppm ozone for 4-hrs. Serum samples were analyzed for metabolites and liver for transcriptional changes immediately post-exposure. Ozone increased circulating triglycerides, cholesterol, free fatty acids, and leptin in sham but not ADREX rats. Ozone-induced inhibition of glucose-mediated insulin release was reversed in ADREX rats. Unlike diminution of hypothalamus and lung mRNA expression changes, ADREX in air-exposed rats (ADREX-air/sham-air) caused differential expression of ~1000 genes in liver. Likewise, ~1000 genes were differentially expressed in ozone-exposed ADREX rats (ADREX-ozone/ADREX-air). Ozone-induced hepatic changes in sham rats reflected enrichment for pathways involving metabolic processes, including acetyl-CoA biosynthesis, TCA cycle, and sirtuins. Upstream predictor analysis identified significant similarity to glucocorticoids and pathways involving CREBBP. These changes were absent in ADREX rats exposed to ozone. However, ozone caused unique changes in ADREX liver mRNA reflecting activation of synaptogenesis, neurovascular coupling, neuroinflammation, and insulin signaling with inhibition of senescence pathways. In these rats, upstream predictor analysis identified numerous microRNAs involved under glucocorticoid insufficiency. These data demonstrate the critical role of adrenal stress hormones in ozone-induced hepatic homeostasis and the need for further research elucidating their role in propagating environmentally driven diseases.
Project description:Mice with a chromosome substitution from A/J strain were compared to parental strains, and acute lung injury following ozone exposure was measured. The candidate gene identified by microarray and genome-wide scans was tested in knockout and pharmacologically altered mice.