Dataset Information

Endothelial inflammatory transcriptional responses to an altered plasma exposome following inhalation of diesel emissions.

ABSTRACT: Air pollution, especially emissions derived from traffic sources, is associated with adverse cardiovascular outcomes. However, it remains unclear how inhaled factors drive extrapulmonary pathology.Previously, we found that canonical inflammatory response transcripts were elevated in cultured endothelial cells treated with plasma obtained after exposure compared with pre-exposure samples or filtered air (sham) exposures. While the findings confirmed the presence of bioactive factor(s) in the plasma after diesel inhalation, we wanted to better examine the complete genomic response to investigate (1) major responsive transcripts and (2) collected response pathways and ontogeny that may help to refine this method and inform the pathogenesis.We assayed endothelial RNA with gene expression microarrays, examining the responses of cultured endothelial cells to plasma obtained from six healthy human subjects exposed to 100??g/m(3) diesel exhaust or filtered air for 2?h on separate occasions. In addition to pre-exposure baseline samples, we investigated samples obtained immediately-post and 24?h-post exposure.Microarray analysis of the coronary artery endothelial cells challenged with plasma identified 855 probes that changed over time following diesel exhaust exposure. Over-representation analysis identified inflammatory cytokine pathways were upregulated both at the 2 and 24?h conditions. Novel pathways related to FOXO transcription factors and secreted extracellular factors were also identified in the microarray analysis.These outcomes are consistent with our recent findings that plasma contains bioactive and inflammatory factors following pollutant inhalation and provide a novel pathway to explain the well-reported extrapulmonary toxicity of ambient air pollutants.

SUBMITTER: Schisler JC

PROVIDER: S-EPMC4765925 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Endothelial inflammatory transcriptional responses to an altered plasma exposome following inhalation of diesel emissions.

Schisler Jonathan C JC Ronnebaum Sarah M SM Madden Michael M Channell Meghan M Campen Matthew M Willis Monte S MS

Inhalation toxicology 20150505 5

<h4>Background</h4>Air pollution, especially emissions derived from traffic sources, is associated with adverse cardiovascular outcomes. However, it remains unclear how inhaled factors drive extrapulmonary pathology.<h4>Objectives</h4>Previously, we found that canonical inflammatory response transcripts were elevated in cultured endothelial cells treated with plasma obtained after exposure compared with pre-exposure samples or filtered air (sham) exposures. While the findings confirmed the prese ...[more]

PMID: 25942053

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Project description:Air pollution, especially emissions derived from traffic sources, is associated with adverse cardiovascular outcomes. However, it remains unclear how inhaled factors drive an extrapulmonary pathology, as the lung is an effective barrier for solid particulates and many gases. Previously, using plasma from healthy human subjects exposed to diesel exhaust under controlled conditions, we found that canonical inflammatory response transcripts of interleukin-8 (IL-8), intracellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) were elevated in endothelial cells treated wih plasma obtained after exposure compared with pre-exposure samples or filtered air (sham) exposures. While the findings confirmed the presence of bioactive factor(s) in the plasma after diesel inhalation, we wanted to better examine the complete genomic response to investigate 1) major responsive transcripts and 2) collected response pathways and ontogeny that may help to refine this method. Thus, we assayed previousy collected RNA with microarray chips, examining the responses of cultured endothelial cells to plasma obtained from 6 healthy human subjects exposed to 100 μg/m3 diesel exhaust or filtered air for 2 h on separate occasions. In addition to pre-exposure baseline samples, we investigated samples obtained immediately post and 24h post exposure. Primary human coronary artery endothelial cells were grown to confluence and treated with 10% plasma for 24 h, followed by isolation of RNA for microarrays. Microarray analysis of the coronary artery endothelial cells challenged with plasma identified 855 probes that change over time following diesel exhaust exposure. Over-representation analysis identified inflammatory cytokine pathways were upregulated both at the 2 and 24 h condition. These outcomes are consistent with our recent findings that plasma contains bioactive and inflammatory factors following pollutant inhalation and provide a novel pathway to explain the well-reported extrapulmonary toxicity of ambient air pollutants.

Project description:BackgroundExposure to traffic-related air pollution (TRAP) is considered a trigger for acute cardiovascular events. Diesel Exhaust (DE) is a major contributor to TRAP in the world. We evaluated the effect of DE inhalation on circulating blood cell populations, hematological indices, and systemic inflammatory cytokines in humans using a specialized facility.MethodsIn a randomized double-blind crossover study balanced to order, 17 metabolic syndrome (MetS) and 15 healthy subjects inhaled filtered air (FA) or DE exposure in two-hour sessions on different days with a minimum 2-week washout period. We collected blood pre-exposure, 7, and 22 hours after exposure initiation and measured the complete blood count and differential. We performed multiplex cytokine assay to measure the changes in the systemic inflammatory cytokines, and endothelial adhesion molecules (n=15). A paired analysis compared the effect of DE and FA exposures for the change from pre-exposure to the subsequent time points.ResultsA significant increase in the hematocrit was noted 7 hrs after DE [1.4% (95% CI: 0.9 to 1.9%)] compared to FA exposure [0.5% (95% CI: -0.09 to 1.0%); p=0.008. The hemoglobin levels increased non-significantly at 7 hrs post DE [0.3 gm/dL (95% CI: 0.2 to 0.5 gm/dL)] versus FA exposure [0.2 gm/dL (95% CI: 0 to 0.3 gm/dL)]; p=0.06. Furthermore, the platelet count increased 22 hrs after DE exposure in healthy, but not in MetS subjects [DE: 16.6 (95% CI: 10.2 to 23) thousand platelets/mL versus [FA: 3.4 (95% CI: -9.5 to 16.3) thousand platelets/mL)]; p=0.04. No DE effect was observed for WBC, neutrophils, lymphocytes or erythrocytes. Using the multiplex assay, small borderline significant increases in matrix metalloproteinase-9, interleukins (IL)-1 beta, 6 and 10 occurred 7 hrs post exposure initiation, whereas E-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule -1, and myeloperoxidase 22 hrs post exposure.ConclusionsOur results suggest that short-term DE exposure results in hemoconcentration and thrombocytosis, which are important determinants of acute cardiovascular events. Multiplex assay showed a non-significant increase in IL-1? and IL-6 immediately post exposure followed by myeloperoxidase and endothelial activation molecules. Further specific assays in a larger population will improve our understanding of the systemic inflammatory mechanisms following acute exposure to TRAP.

Project description:Background: Epidemiologic associations between acutely increased cardiorespiratory morbidity and mortality and particulate air pollution are well-established, but the effects of acute pollution exposure on human gene expression changes are not well understood. Objectives: In order to identify potential mechanisms underlying epidemiologic associations between air pollution and morbidity, we explored changes in gene expression in humans following inhalation of fresh diesel exhaust (DE), a model for particulate air pollution. Methods: 14 ethnically homogeneous (white males), young, healthy subjects underwent sixty minute inhalation exposures on 2 separate days with clean air (CA) or freshly generated and diluted DE at a concentration of 300 Î¼g/m3 PM2.5. Prior to and 24 hours following each session, whole blood was sampled and fractionated for PBMC isolation, RNA extraction, and generation of cDNA, followed by hybridizationÂ withÂ Agilent Whole Human Genome (4X44K) arrays. Results: Oxidative stress and the ubiquitin proteasome pathway, as well as the coagulation system, were among hypothesized pathways identified by analysis of differentially expressed genes. Nine genes from these pathways were validated using real-time PCR comparing fold change in expression between DE exposed and clean (CA) days. Quantitative gene fold changes generated by real-time PCR were consistent with the directional fold changes from the microarray analysis. Conclusions: Changes in gene expression connected with key oxidative stress, protein degradation, and coagulation pathways are likely to underlie observed physiologic and clinical outcomes and suggest specific avenues and sensitive time points for further physiologic exploration. Diesel exhaust inhalation exposure-induced human gene expression changes were measured in peripheral blood mononuclear cells. 14 white males subjects were seated in a controlled environment facility for 2 separate 60 minute inhalation exposures which occurred at least 1 week apart to either clean air and freshly generate or diluted diesel exhaust (300ug/m3 PM2.5) .Blood collection occurred immediately prior to and 24 hours following exposures. Two microarrays per subject were completed using Agilent Whole Human Genome (4X44K) arrays. Genes that were of interest to our research group were verified using Real Time PCR analysis.

Project description:Epidemiological observations of urban inhalation exposures to diesel exhaust (DE) and ozone (O3) have shown pre-clinical cardiopulmonary responses in humans. Identifying the key biological mechanisms that initiate these health bioindicators is difficult due to variability in environmental exposure in time and from person to person. Previously, environmentally controlled human exposure chambers have been used to study DE and O3 dose-response patterns separately, but investigation of co-exposures has not been performed under controlled conditions. Because a mixture is a more realistic exposure scenario for the general public, in this study we investigate the relationships of urban levels of urban-level DE exposure (300 μg/m3), O3 (0.3 ppm), DE + O3 co-exposure, and innate immune system responses. Fifteen healthy human volunteers were studied for changes in ten inflammatory cytokines (interleukins 1β, 2, 4, 5, 8, 10, 12p70 and 13, IFN-γ, and TNF-α) and counts of three white blood cell types (lymphocytes, monocytes, and neutrophils) following controlled exposures to DE, O3, and DE+O3. The results show subtle cytokines responses to the diesel-only and ozone-only exposures, and that a more complex (possibly synergistic) relationship exists in the combination of these two exposures with suppression of IL-5, IL-12p70, IFN-γ, and TNF-α that persists up to 22-hours for IFN-γ and TNF-α. The white blood cell differential counts showed significant monocyte and lymphocyte decreases and neutrophil increases following the DE + O3 exposure; lymphocytes and neutrophils changes also persist for at least 22-hours. Because human studies must be conducted under strict safety protocols at environmental levels, these effects are subtle and are generally only seen with detailed statistical analysis. This study indicates that the observed associations between environmental exposures and cardiopulmonary effects are possibly mediated by inflammatory response mechanisms.

Dataset Information

Endothelial inflammatory transcriptional responses to an altered plasma exposome following inhalation of diesel emissions.

Publications

Endothelial inflammatory transcriptional responses to an altered plasma exposome following inhalation of diesel emissions.

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