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2621643 
Journal Article 
Abstract 
Diesel exhaust particles induce dissociation of Occludin and zonula occludens 1 (ZO-1) in alveolar epithelial cells 
Caraballo, JC; Westphal, W; Moninger, T; Comellas, AP 
2010 
Yes 
American Journal of Respiratory and Critical Care Medicine
ISSN: 1073-449X
EISSN: 1535-4970 
181 
A1026 
English 
WOS:000208771000027 
is part of a larger document 3452678 Proceedings of the American Thoracic Society 2010 International Conference, May 14-19, 2010, New Orleans
Rationale: Diesel exhaust particles (DEP) are responsible for the development of lung injury and inflammation. We recently reported that air particulate matter (PM) affects alveolar epithelial barrier, altering the distribution of occludin at the tight junctions (TJ) of alveolar epithelial cells (AEC). Occludin is bound to actin cytoskeleton by zonula occludens-1 (ZO-1) proteins, and this association is essential to maintain epithelial barrier integrity. We hypothesized that DEP induces Occludin and ZO-1 dissociation, via reactive oxygen species (ROS)-PKC-zeta (PKC-ζ) dependent pathway, hence resulting in a dysfunctional epithelial barrier and the development of lung injury

Methods: AEC were exposed to DEP and titanium dioxide (TiO2) for different time intervals. TJ integrity was assessed by measuring transepithelial electrical conductance (TEC) and lanthanum (La ) labeling of TJ by transmission electron microscopy (TEM). 3+ Co-immunoprecipitation and immunofluorescence (IF) microscopy were performed to determine occluding-ZO-1 association. Overexpression of antioxidant enzymes manganese superoxide dismutase (MnSOD) and Catalase was achieved by infecting AEC with the respective adenovirus containing recombinant DNA. PKC-ζ pseudosubstrate inhibitor was used to block PKC-ζ activity.

Results: DEP increased TEC and labeling of TJ permeability by La in AEC. Co-localization and co-immunoprecipitation of occludin-ZO-1 3+ was decreased by DEP. Overexpression of MnSOD and Catalase prevented the DEP-induced increased in TEC. In addition, overexpression of these enzymes conserved the association of occludin and ZO-1 and the barrier integrity in AEC after exposure to DEP. Furthermore, inhibition of PKC-ζ prevented the DEP-induced dissociation of occludin and ZO-1.

Conclusions: DEP induces dissociation of occludin and ZO-1 at the TJ and disrupts the alveolar epithelial barrier. This effect is prevented by scavenging ROS and blocking PKC-ζ. 
American Thoracic Society 2010 International Conference 
New Orleans, LA 
May 14-19, 2010