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:Genome wide DNA methylation profiling of cord blood in Faroe Island cohort. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 485,000 CpGs in cord blood samples. Background: Faroe islanders consume marine foods contaminated with methylmercury (MeHg), polychlorinated biphenyls (PCBs), and other toxicants associated with chronic disease risks. Differential DNA methylation at specific CpG sites in cord blood may serve as a surrogate biomarker of health impacts from chemical exposures. Objective: We aimed to identify key environmental chemicals in cord blood associated with DNA methylation changes in a population with elevated exposure to chemical mixtures. Method: We studied 72 participants of a Faroese birth cohort recruited between 1986 and 1987 and followed until adulthood. The cord blood DNA methylome was profiled using Infinium Methylation 450K BeadChips. We determined the associations of CpG site changes with concentrations of MeHg, major PCBs, other organochlorine compounds, (hexachlorobenzene [HCB], p,p’-dichlorodiphenyldichloroethylene [p,p’-DDE] and p,p’-dichlorodiphenyltrichloroethane) and perfluoroalkyl substances. Results: In a combined sex analysis, among the 16 chemicals studied, PCB congener 105 (CB-105) exposure was associated with the majority of differentially methylated CpG sites (214 out of a total of 250). In female-only-analysis, only 73 CB-105 associated CpG sites were detected, 44 of which were mapped to genes in the ELAV1-associated cancer network. In males-only, methylation changes were seen for perfluorooctane sulfonate, HCB, and p,p’-DDE in 10,598; 1,238; and 1,473 CpG sites, respectively, 15% of which were enriched in cytobands of the X chromosome associated with neurological disorders. Conclusion: In this multiple-pollutant and genome-wide study, we identified key epigenetic toxicants. The significant enrichment of specific X-chromosome sites in males implies potentially sex-specific epigenome responses to prenatal chemical exposures.

Project description:Bronchial epithelial cells, which line the airway of the respiratory tract, undergo genome-wide level changes in gene expression and DNA methylation particularly when exposed to fine (< 2.5 µm) PM (PM2.5). Although some of these changes have been reported in other studies, a comparison of how different doses and duration of exposure affect both the gene transcriptome and DNA methylome has not been done. We exposed BEAS-2B, a bronchial epithelial cell line, to a single exposure of high (30 µg/cm2) or low (1 µg/cm2) dose of PM2.5 (obtained from Beijing, China in 2015) for 24 hours. We also exposed BEAS-2B cells to repeated exposures of low dose (1 µg/cm2) PM2.5 every day for seven days. We then examined the transcriptomic changes (by RNA-Seq) and DNA methylomic changes (by enhanced reduced representation bisulfite sequencing). Widespread changes in gene expression occurred after cells were exposed to a single, high dose (30 µg/cm2) exposure of PM2.5 for 24 h. These genes were enriched in pathways regulating MAPK signaling, PI3K-Akt signaling, cytokine interactions, IL6, and P53. DNA methylomic analysis showed that nearly half of the differentially expressed genes were found to also have DNA methylation changes. Cells exposed to a lower dose (1 µg/cm2) of PM2.5 demonstrated a similar, but more attenuated change in gene expression. Cells exposed to repeated doses of PM2.5 for seven days, however, demonstrated a different set of genes that were differentially expressed compared to a single exposure. The DNA methylation changes that occurred with repeated, low dose exposure were also different from single high dose exposures and skewed towards overall hypomethylation. This hypomethylation corresponded with an increase in expression of ten-eleven translocation enzymes. Overall, these data demonstrate how variations in dose and duration of PM2.5 exposure induce distinct differences in the transcriptomic and DNA methylomic profile of bronchial epithelial cells.

Project description:Atmospheric fine particulate matter (PM2.5) causes severe haze in China and is regarded as a threat to human health. The health effects of PM2.5 vary location by location due to the variation in size distribution, chemical com position, and sources. In this study, the cytotoxicity effect, oxidative stress, and gene expression regulation of PM2.5 in Chengdu and Chongqing, two typical urban areas in southern China, were evaluated. Urban PM2.5 in summer and winter significantly inhibited cell viability and increased reactive oxygen species (ROS) levels in A549 cells. Notably, PM2.5 in winter exhibited higher cytotoxicity and ROS level than summer. Moreover, in this study, PM2.5 commonly induced cancer-related gene expression such as cell adhesion molecule 1(PECAM1), interleukin 24 (IL24), and cytochrome P450 (CYP1A1); meanwhile, PM2.5 commonly acted on cancer-related biological functions such as cell-substrate junction, cell-cell junction, and focal adhesion. In partic ular, PM2.5 in Chengdu in summer had the highest carcinogenic potential among PM2.5 at the two sites in summer and winter. Importantly, cancer-related genes were uniquely targeted by PM2.5, such as epithelial splicing regu latory protein 1 (ESRP1) and membrane-associated ring-CH-type finger 1 (1-Mar) by Chengdu summer PM2.5; collagen type IX alpha 3 chain (COL9A3) by Chengdu winter PM2.5; SH2 domain-containing 1B (SH2D1B) by Chongqing summer PM2.5; and interleukin 1 receptor-like 1 (IL1RL1) and zinc finger protein 42 (ZNF423) by Chongqing winter PM2.5. Meanwhile, important cancer-related biological functions were specially induced by PM2.5, such as cell cycle checkpoint by Chengdu summer PM2.5; macromolecule methylation by Chengdu win ter PM2.5; endoplasmic reticulum-Golgi intermediate compartment membrane by Chongqing summer PM2.5;and cellular lipid catabolic process by Chongqing winter PM2.5. Conclusively, in the typical urban areas of southern China, both summer and winter PM2.5 illustrated significant gene regulation effects. This study contrib utes to evaluating the adverse health effects of PM2.5 in southern China and providing public health suggestions for policymakers.

Project description:Background: Diesel exhaust (DE) is the primary source of urban fine particulate matter, which has been associated with cardiovascular disease in epidemiological studies. These effects may be related to oxidative stress and systemic inflammation with resulting perturbation of vascular homeostasis. Peripheral leukocytes are involved in both inflammation and control of vascular homeostasis. Objectives: We conducted an exploratory study using microarray techniques to analyze whether global gene expression in peripheral blood mononuclear cells (PBMCs) can inform on potential mechanisms of effect of DE inhalation. Methods: In a double-blind, crossover, controlled exposure study, healthy adult volunteers were exposed in randomized order to filtered air (FA) and diluted DE in two-hour sessions. We isolated RNA (Trizol/Qiagen method) form PBMCs before, and two times after each exposure. RNA samples were arrayed using the AffymetrixÂ® platform (GeneChipÂ® Human Genome U133 Plus 2.0 Array). Results: Microarray analyses were conducted on five subjects with available RNA sample form exposures to FA and to the highest DE inhalation (200 Âµg/mÂ³ of fine particulate matter). Following data normalization and statistical analysis, a total of 1290 out of 54,675 probe sets with significant evidence for differential expression (more than 1.5-fold up or down regulated with p < 0.05) were identified. These include genes involved in inflammatory response (e.g., IL8RA, TNFAIP6, FOS), oxidative stress (e.g., HMOX1, BAX, PRDX1,), and in biochemical pathways like mitogen-activated protein kinases (MAPK) and tight junction pathways. Conclusions: These data suggest that DE may exert time-dependent changes in gene expression in PBMCs in healthy individuals. Genes that may be affected by DE inhalation are involved in inflammatory and oxidative stress processes. Experiment Overall Design: We conducted a crossover, double-blind experiment, randomized to order of DE and filtered-air (FA) exposure with each participant exposed on four different days to each of four conditions: FA and DE calibrated to 50Âµg/m3 (DE50), 100Âµg/m3 (DE100), and 200Âµg/m3 (DE200) of fine particulate matter (PM2.5- particles with aerodynamic diameter 2.5Âµm or less). Exposure sessions were conducted at least 2 weeks apart.

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Epigenome-wide analysis identifies pollution-sensitive loci in fibrotic interstitial lung disease

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