title: Differential injurious effects of ambient and traffic-derived particulate matter on airway epithelial cells.
abstract: OBJECTIVE
  Exposure to airborne particulate matter (PM) may promote development of childhood asthma and trigger acute exacerbations of existing asthma via injury to airway epithelial cells (AEC).
  
  
  METHODS
  We compared the response of AEC to ambient particulates with median aerodynamic diameters of <10 μm or <2.5 μm from the Sydney metropolitan region (Sydney PM10 or PM2.5), to traffic-derived particulates from the exhaust stack of a motorway tunnel or to inert carbon black as a control.
  
  
  RESULTS
  Sydney PM10 strongly stimulated messenger RNA expression and secretion of the pro-inflammatory cytokines interleukin 6 (IL-6) and chemokine (C-X-C motif) ligand 1 (CXCL1) by mouse tracheal AEC. In contrast, traffic-derived particulates did not. Similarly, PM10 stimulated expression of IL6, IL8 and IL1B by human AEC. Mass spectrometric analysis showed that PM10 contained much higher levels of elements associated with dusts of geological origin. In contrast, tunnel soot contained much higher levels of various organic compounds, notably including long straight-chain alkanes and diesel-derived polycyclic aromatic hydrocarbons. Sydney PM2.5, as well as PM10 collected during a period including a major dust storm, both of which contained relatively lower levels of iron but similar levels of other crustal elements, did not stimulate expression or secretion of CXCL1 by mouse AEC.
  
  
  CONCLUSIONS
  Ambient PM10 is likely to be more important than traffic-derived PM in causing injury to AEC leading to production of pro-inflammatory cytokines. The injurious effects may be related to the presence of iron in the coarse fraction of airborne PM. These findings are likely to be relevant to the pathogenesis of asthma.
authors.affiliation: Department of Pathology, School of Medical Sciences, UNSW Australia, Sydney, Australia.
authors.forename: Rakesh K
authors.initials: RK
authors.lastname: Kumar
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Shadie
authors.forename: Martin P
authors.initials: MP
authors.lastname: Bucknall
authors.forename: Helen
authors.initials: H
authors.lastname: Rutlidge
authors.forename: Linda
authors.initials: L
authors.lastname: Garthwaite
authors.forename: Cristan
authors.initials: C
authors.lastname: Herbert
authors.forename: Brendan
authors.initials: B
authors.lastname: Halliburton
authors.forename: Kristy S
authors.initials: KS
authors.lastname: Parsons
authors.forename: Peter A B
authors.initials: PA
authors.lastname: Wark
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D002478:Cells, Cultured; D054360:Chemokine CXCL1 / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D006801:Humans; D053583:Interleukin-1beta / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D007501:Iron / Q000032:analysis / Q000633:toxicity; D051379:Mice; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity; D012333:RNA, Messenger / Q000378:metabolism; D020545:Respiratory Mucosa; D053260:Soot / Q000737:chemistry / Q000633:toxicity*; D014132:Trachea; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; C475829:CXCL1 protein, human; D054360:Chemokine CXCL1; D016207:Cytokines; D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; D012333:RNA, Messenger; D053260:Soot; D014409:Tumor Necrosis Factor-alpha; D001335:Vehicle Emissions; D007501:Iron
keywords: airborne pollutant; airway epithelium; asthma; mass spectrometry; pro-inflammatory cytokine