© 2002 American Thoracic Society DOI: 10.1165/rcmb.2001-0005OC Size Fractions of Ambient Particulate Matter Induce Granulocyte Macrophage Colony–Stimulating Factor in Human Bronchial Epithelial Cells by Mitogen-Activated Protein Kinase PathwaysDivision of Pulmonary and Critical Care Medicine, Department of Medicine; Department of Environmental Medicine, Nelson Institute of Environmental Medicine; and Department of Pathology, New York University School of Medicine, New York, New York Address correspondence to: Joan Reibman, M.D., New York University School of Medicine, Division of Pulmonary and Critical Care Medicine, 550 1st Avenue, Room NB7N24, New York, NY 10016. E-mail: reibmj01{at}gcrc.med.nyu.edu Environmental pollutants, including ambient particulate matter (PM), increase respiratory morbidity. Studies of model PM particles, including residual oil fly ash and freshly generated diesel exhaust particles, have demonstrated that PM affects inflammatory airway responses. Neither of these particles completely represents ambient PM, and therefore questions remain about ambient particulates. We hypothesized that ambient PM of different size fractions collected from an urban environment (New York City air), would activate primary culture human bronchial epithelial cells (HBECs). Because of the importance of granulocyte-macrophage colony–stimulating factor (GM-CSF) on inflammatory and immunomodulatory processes, we focused our studies on this cytokine. We demonstrated that the smallest size fraction (ultrafine/fine; < 0.18 µm) of ambient PM (11 µg/cm2), upregulated GM-CSF production (2-fold increase). The absence of effect of carbon particles of similar size, and the day-to-day variation in response, suggested that the chemical composition, but not the particle itself, was necessary for GM-CSF induction. Activation of the extracellular signal-regulated kinase and the p38 mitogen-activated protein kinase was associated with, and necessary for, GM-CSF release. These studies serve to corroborate and extend those on model particles. Moreover, they emphasize the role of the smallest size ambient particles in airway epithelial cell responses.
Abbreviations: antigen-presenting cells, APC • diesel exhaust particles, DEP • enzyme-linked immunosorbent assay, ELISA • extracellular signal-related kinase, ERK • granulocyte-macrophage colony–stimulating factor, GM-CSF • intercellular adhesion molecule, ICAM • interleukin, IL • mitogen-activated protein kinase, MAPK • mass median aerodynamic diameter, MMAD • primary culture human bronchial epithelial cells, HBECs • particulate matter, PM • residual oil fly ash, ROFA • tumor necrosis factor- This article has been cited by other articles:
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