Novel Mechanisms of Ozone-Induced Pulmonary Inflammation and Resolution, and the Potential Protective Role of Scavenger Receptor BI.
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ABSTRACT:
SUBMITTER: Gowdy KM
PROVIDER: S-EPMC8126671 | biostudies-literature | 2021 Mar
REPOSITORIES: biostudies-literature
Publications
Novel Mechanisms of Ozone-Induced Pulmonary Inflammation and Resolution, and the Potential Protective Role of Scavenger Receptor BI.
Gowdy K M KM Kilburg-Basnyat B B Hodge M X MX Reece S W SW Yermalitsk V V Davies S S SS Manke J J Armstrong M L ML Reisdorph N N Tighe R M RM Shaikh S R SR
Research report (Health Effects Institute) 20210301 204
<h4>Introduction</h4>Increases in ambient levels of ozone (O<sub>3</sub>), a criteria air pollutant, have been associated with increased susceptibility and exacerbations of chronic pulmonary diseases through lung injury and inflammation. O<sub>3</sub> induces pulmonary inflammation, in part by generating damage-associated molecular patterns (DAMPs), which are recognized by pattern recognition receptors (PRRs), such as toll-like receptors (TLRs) and scavenger receptors (SRs). This inflammatory re ...[more]
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Project description:Background: The mechanisms underlying ozone (O3)-induced pulmonary inflammation remain unclear. Interleukin (IL)-10 is an anti-inflammatory cytokine that is known to inhibit inflammatory mediators. Objectives: The current study investigated the molecular mechanisms underlying IL-10-mediated attenuation of O3-induced pulmonary inflammation in mice. Methods: Il10-deficient (Il10-/-) and wild type (Il10+/+) mice were exposed to 0.3-ppm O3 or filtered air for 24, 48 or 72 hr. Immediately following exposure, differential cell counts, and total protein (a marker of lung permeability) were assessed from bronchoalveolar lavage fluid (BALF). mRNA and protein levels of cellular mediators were determined from lung homogenates. We also utilized global mRNA expression analyses of lung tissue with Ingenuity Pathway Analyses (IPA) to identify patterns of gene expression through which IL-10 modifies O3-induced inflammation. Results: Mean numbers of BALF polymorphonuclear leukocytes (PMNs) were significantly greater in Il10-/- mice than in Il10+/+ mice after exposure to O3 at all time points tested. O3-enhanced nuclear NF-kB translocation was elevated in the lungs of Il10-/- compared to Il10+/+ mice. Gene expression analyses revealed several key IL-10 and O3-dependent mediators, including IL-6, MIP-2, IL-1 and CD86. Conclusions: Results indicated that IL-10 protects against O3-induced pulmonary neutrophilic inflammation and cell proliferation. Moreover, gene expression analyses identified three response pathways and several novel genetic targets (e.g. Ccr1, Socs3, Il33, Hat1, and Gale) through which IL10 may modulate the innate and adaptive immune response. These novel mechanisms of protection against the pathogenesis of O3-induced pulmonary inflammation may also provide potential therapeutic targets to protect susceptible individuals. PARALLEL study design with 26 samples. Biological replicates: 2 to 3 replicates per group with wild type air exposed animals as controls for each time point (24, 48, 72 hours). Time-Course, Dose-Response, Strain comparison
2011-10-18 | E-GEOD-25095 | biostudies-arrayexpress
Project description:BackgroundThe mechanisms underlying ozone (O₃)-induced pulmonary inflammation remain unclear. Interleukin-10 (IL-10) is an anti-inflammatory cytokine that is known to inhibit inflammatory mediators.ObjectivesWe investigated the molecular mechanisms underlying interleuken-10 (IL-10)-mediated attenuation of O₃-induced pulmonary inflammation in mice.MethodsIl10-deficient (Il10(-/-)) and wild-type (Il10(+/+)) mice were exposed to 0.3 ppm O₃ or filtered air for 24, 48, or 72 hr. Immediately after exposure, differential cell counts and total protein (a marker of lung permeability) were assessed from bronchoalveolar lavage fluid (BALF). mRNA and protein levels of cellular mediators were determined from lung homogenates. We also used global mRNA expression analyses of lung tissue with Ingenuity Pathway Analysis to identify patterns of gene expression through which IL-10 modifies O₃-induced inflammation.ResultsMean numbers of BALF polymorphonuclear leukocytes (PMNs) were significantly greater in Il10(-/-) mice than in Il10(+/+) mice after exposure to O₃ at all time points tested. O₃-enhanced nuclear NF-κB translocation was elevated in the lungs of Il10(-/-) compared with Il10(+/+) mice. Gene expression analyses revealed several IL-10-dependent and O₃-dependent mediators, including macrophage inflammatory protein 2, cathepsin E, and serum amyloid A3.ConclusionsResults indicate that IL-10 protects against O₃-induced pulmonary neutrophilic inflammation and cell proliferation. Moreover, gene expression analyses identified three response pathways and several genetic targets through which IL-10 may modulate the innate and adaptive immune response. These novel mechanisms of protection against the pathogenesis of O₃-induced pulmonary inflammation may also provide potential therapeutic targets to protect susceptible individuals.
| S-EPMC3002191 | biostudies-literature
Project description:Background: The mechanisms underlying ozone (O3)-induced pulmonary inflammation remain unclear. Interleukin (IL)-10 is an anti-inflammatory cytokine that is known to inhibit inflammatory mediators. Objectives: The current study investigated the molecular mechanisms underlying IL-10-mediated attenuation of O3-induced pulmonary inflammation in mice. Methods: Il10-deficient (Il10-/-) and wild type (Il10+/+) mice were exposed to 0.3-ppm O3 or filtered air for 24, 48 or 72 hr. Immediately following exposure, differential cell counts, and total protein (a marker of lung permeability) were assessed from bronchoalveolar lavage fluid (BALF). mRNA and protein levels of cellular mediators were determined from lung homogenates. We also utilized global mRNA expression analyses of lung tissue with Ingenuity Pathway Analyses (IPA) to identify patterns of gene expression through which IL-10 modifies O3-induced inflammation. Results: Mean numbers of BALF polymorphonuclear leukocytes (PMNs) were significantly greater in Il10-/- mice than in Il10+/+ mice after exposure to O3 at all time points tested. O3-enhanced nuclear NF-kB translocation was elevated in the lungs of Il10-/- compared to Il10+/+ mice. Gene expression analyses revealed several key IL-10 and O3-dependent mediators, including IL-6, MIP-2, IL-1 and CD86. Conclusions: Results indicated that IL-10 protects against O3-induced pulmonary neutrophilic inflammation and cell proliferation. Moreover, gene expression analyses identified three response pathways and several novel genetic targets (e.g. Ccr1, Socs3, Il33, Hat1, and Gale) through which IL10 may modulate the innate and adaptive immune response. These novel mechanisms of protection against the pathogenesis of O3-induced pulmonary inflammation may also provide potential therapeutic targets to protect susceptible individuals.
2011-10-19 | GSE25095 | GEO
Project description:Damage associated molecular patterns (DAMPs) are molecules released from dead/dying cells following toxicant and/or environmental exposures that activate the immune response through binding of pattern recognition receptors (PRRs). Excessive production of DAMPs or failed clearance leads to chronic inflammation and delayed inflammation resolution. One category of DAMPs are oxidized phospholipids (oxPLs) produced upon exposure to high levels of oxidative stress, such as following ozone (O3) induced inflammation. OxPLs are bound by multiple classes of PRRs that include scavenger receptors (SRs) such as SR class B-1 (SR-BI) and toll-like receptors (TLRs). Interactions between oxPLs and PRRs appear to regulate inflammation; however, the role of SR-BI in oxPL-induced lung inflammation has not been defined. Therefore, we hypothesize that SR-BI is critical in protecting the lung from oxPL-induced pulmonary inflammation/injury. To test this hypothesis, C57BL/6J (WT) female mice were dosed with oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (oxPAPC) by oropharyngeal aspiration which increased pulmonary SR-BI expression. Following oxPAPC exposure, SR-BI deficient (SR-BI-/-) mice exhibited increased lung pathology and inflammatory cytokine/chemokine production. Lipidomic analysis revealed that SR-BI-/- mice had an altered pulmonary lipidome prior to and following oxPAPC exposure, which correlated with increased oxidized phosphatidylcholines (PCs). Finally, we characterized TLR4-mediated activation of NF-κB following oxPAPC exposure and discovered that SR-BI-/- mice had increased TLR4 mRNA expression in lung tissue and macrophages, increased nuclear p65, and decreased cytoplasmic IκBα. Overall, we conclude that SR-BI is required for limiting oxPAPC-induced lung pathology by maintaining lipid homeostasis, reducing oxidized PCs, and attenuating TLR4-NF-κB activation, thereby preventing excessive and persistent inflammation.
| S-EPMC9983330 | biostudies-literature
Project description:Pulmonary responses to ozone, a common air pollutant, are augmented in obese individuals. Adiponectin, an adipose-derived hormone that declines in obesity, has regulatory effects on the immune system. To determine the role of adiponectin in the pulmonary inflammation induced by extended (48-72 h) low-dose (0.3 parts per million) exposure to ozone, adiponectin-deficient (Adipo(-/-)) and wild-type mice were exposed to ozone or to room air. In wild-type mice, ozone exposure increased total bronchoalveolar lavage (BAL) adiponectin. Ozone-induced lung inflammation, including increases in BAL neutrophils, protein (an index of lung injury), IL-6, keratinocyte-derived chemokine, LPS-induced CXC chemokine, and G-CSF were augmented in Adipo(-/-) versus wild-type mice. Ozone also increased IL-17A mRNA expression to a greater extent in Adipo(-/-) versus wild-type mice. Moreover, compared with control Ab, anti-IL-17A Ab attenuated ozone-induced increases in BAL neutrophils and G-CSF in Adipo(-/-) but not in wild-type mice, suggesting that IL-17A, by promoting G-CSF release, contributed to augmented neutrophilia in Adipo(-/-) mice. Flow cytometric analysis of lung cells revealed that the number of CD45(+)/F4/80(+)/IL-17A(+) macrophages and γδ T cells expressing IL-17A increased after ozone exposure in wild-type mice and further increased in Adipo(-/-) mice. The IL-17(+) macrophages were CD11c(-) (interstitial macrophages), whereas CD11c(+) macrophages (alveolar macrophages) did not express IL-17A. Taken together, the data are consistent with the hypothesis that adiponectin protects against neutrophil recruitment induced by extended low-dose ozone exposure by inhibiting the induction and/or recruitment of IL-17A in interstitial macrophages and/or γδ T cells.
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Project description:To investigate the mechanisms by which macrophage scavenger receptor BI (SR-BI) regulates macrophage cholesterol homeostasis and protects against atherosclerosis.The expression and function of SR-BI was investigated in cultured mouse bone marrow-derived macrophages (BMM). SR-BI, the other scavenger receptors SRA and CD36 and the ATP-binding cassette transporters ABCA1 and ABCG1 were each distinctly regulated during BMM differentiation. SR-BI levels increased transiently to significant levels during culture. SR-BI expression in BMM was reversibly down-regulated by lipid loading with modified LDL; SR-BI was shown to be present both on the cell surface as well as intracellularly. BMM exhibited selective HDL CE uptake, however, this was not dependent on SR-BI or another potential candidate glycosylphosphatidylinositol anchored high density lipoprotein binding protein 1 (GPIHBP1). SR-BI played a significant role in facilitating bidirectional cholesterol flux in non lipid-loaded cells. SR-BI expression enhanced both cell cholesterol efflux and cholesterol influx from HDL, but did not lead to altered cellular cholesterol mass. SR-BI-dependent efflux occurred to larger HDL particles but not to smaller HDL(3). Following cholesterol loading, ABCA1 and ABCG1 were up-regulated and served as the major contributors to cholesterol efflux, while SR-BI expression was down-regulated.Our results suggest that SR-BI plays a significant role in macrophage cholesterol flux that may partly account for its effects on atherogenesis.
| S-EPMC3139003 | biostudies-literature