title: Comparative gene responses to collected ambient particles in vitro: endothelial responses.
abstract: Epidemiologic studies associate exposure to ambient particulate matter (APM) with increased cardiovascular mortality. Since both pulmonary inflammation and systemic circulation of ultrafine particles are hypothesized as initiating cardiovascular effects, we examined responses of potential target cells in vitro. Human aortic endothelial cells (HAEC) were exposed to 10 μg/ml fine and ultrafine APM collected in an urban setting in summer 2006 or winter 2007 in the San Joaquin Valley, California. RNA isolated after 3 h was analyzed with high-density oligonucleotide arrays. Summer APM treatment affected genes involved in xenobiotic and oxidoreductase activity, transcription factors, and inflammatory responses in HAEC, while winter APM had a robust xenobiotic but lesser inflammatory response. Real-time polymerase chain reaction analysis confirmed that particulate matter (PM)-treated HAEC increased mRNA levels of xenobiotic response enzymes CYP1A1, ALDH1A3, and TIPARP and cellular stress response transcription factor ATF3. Inflammatory response genes included E-selectin, PTGS2, CXCL-2 (MIP-2α), and CCL-2 (MCP-1). Multiplex protein assays showed secretion of IL-6 and MCP-1 by HAEC. Since induction of CYP1A1 is mediated through the ligand-activated aryl hydrocarbon receptor (AhR), we demonstrated APM induced AhR nuclear translocation by immunofluorescence and Western blotting and activation of the AhR response element using a luciferase reporter construct. Inhibitor studies suggest differential influences of polycyclic aromatic hydrocarbon signaling, ROS-mediated responses and endotoxin alter stress and proinflammatory endothelial cell responses. Our findings demonstrate gene responses correlated with current concepts that systemic inflammation drives cardiovascular effects of particulate air pollution. We also demonstrate a unique pattern of gene responses related to xenobiotic metabolism in PM-exposed HAEC.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, California, USA.
authors.forename: Hnin H
authors.initials: HH
authors.lastname: Aung
authors.forename: Michael W
authors.initials: MW
authors.lastname: Lame
authors.forename: Kishorchandra
authors.initials: K
authors.lastname: Gohil
authors.forename: Guochun
authors.initials: G
authors.lastname: He
authors.forename: Michael S
authors.initials: MS
authors.lastname: Denison
authors.forename: John C
authors.initials: JC
authors.lastname: Rutledge
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Wilson
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism; D054426:Chemokine CXCL2 / Q000235:genetics; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D019040:E-Selectin / Q000235:genetics; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D052638:Particulate Matter / Q000633:toxicity*; D016133:Polymerase Chain Reaction; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics
chemical_list: C111835:CCL2 protein, human; D018932:Chemokine CCL2; D054426:Chemokine CXCL2; D019040:E-Selectin; D015850:Interleukin-6; D052638:Particulate Matter; D018336:Receptors, Aryl Hydrocarbon; D003577:Cytochrome P-450 Enzyme System; D019363:Cytochrome P-450 CYP1A1