title: Protein kinase C-ζ mediates lung injury induced by diesel exhaust particles.
abstract: Recently, we reported that diesel exhaust particles (DEPs) disrupt tight junctions (TJs) in alveolar epithelial cells (AECs) via an increase in reactive oxygen species (ROS). In this study, we investigated the role of protein kinase C (PKC)-ζ activation in DEP-induced lung injury. C57/bl6 mice were instilled intratracheally with 50 μl of saline containing 100 μg of DEPs or titanium dioxide (TiO2). Twenty-four hours later, bronchoalveolar lavage was performed to assess neutrophil counts and protein concentrations. In addition, in vitro experiments were performed in primary rat and human AECs exposed to DEPs (50 μg/cm(2)) for 3 hours. Transepithelial electrical conductance was measured, and TJ protein association was analyzed by immunoprecipitation. To determine whether the overexpression of antioxidants prevented DEP-induced lung injury, AECs and mice were infected with adenoviruses containing catalase and manganese superoxide dismutase (MnSOD) plasmids. In vivo, the overexpression of catalase and MnSOD prevented DEP-induced neutrophil recruitment. The inhibition of PKC-ζ activation also prevented DEP-induced neutrophil recruitment in vivo. In vitro, DEPs activated PKC-ζ in AECs, but not in alveolar macrophages. Using a specific myristolated PKC-ζ pseudosubstrate pepetide (PKC-ζ ps), we showed that PKC-ζ mediated the DEP-induced dissociation of occludin and zonula occludin-1 (ZO1) in rat and human AECs. In addition, the overexpression of constitutively active PKC-ζ induced the dissociation of occludin and ZO1 in AECs. DEP-induced TJ disruption occurs via PKC-ζ. TJ disruption seems to be in part responsible for DEP-induced lung injury.
authors.affiliation: Division of Pulmonary, Critical Care, and Occupation Medicine, Department of Internal Medicine, University of Iowa, 200 Hawkins Drive, C 331 GH, Iowa City, IA 52242, USA.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Caraballo
authors.forename: Jennifer
authors.initials: J
authors.lastname: Borcherding
authors.forename: Peter S
authors.initials: PS
authors.lastname: Thorne
authors.forename: Alejandro P
authors.initials: AP
authors.lastname: Comellas
mesh_terms: D000818:Animals; D018893:Bronchoalveolar Lavage; D002374:Catalase / Q000378:metabolism; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D055370:Lung Injury / Q000139:chemically induced* / Q000201:enzymology* / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism; D062793:Occludin / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism; D014025:Titanium / Q000633:toxicity; D001335:Vehicle Emissions / Q000633:toxicity*; D062826:Zonula Occludens-1 Protein / Q000378:metabolism; D000099221:Protein Kinase C zeta
chemical_list: D002374:Catalase; D062793:Occludin; D011493:Protein Kinase C; D013482:Superoxide Dismutase; D014025:Titanium; D001335:Vehicle Emissions; D062826:Zonula Occludens-1 Protein; D000099221:Protein Kinase C zeta; C009495:titanium dioxide