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Protein kinase C-? 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)-? activation in DEP-induced lung injury. C57/bl6 mice were instilled intratracheally with 50 ?l of saline containing 100 ?g 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 ?g/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-? activation also prevented DEP-induced neutrophil recruitment in vivo. In vitro, DEPs activated PKC-? in AECs, but not in alveolar macrophages. Using a specific myristolated PKC-? pseudosubstrate pepetide (PKC-? ps), we showed that PKC-? 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-? induced the dissociation of occludin and ZO1 in AECs. DEP-induced TJ disruption occurs via PKC-?. TJ disruption seems to be in part responsible for DEP-induced lung injury.

SUBMITTER: Caraballo JC

PROVIDER: S-EPMC3604088 | biostudies-other | 2013 Mar

REPOSITORIES: biostudies-other

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Protein kinase C-ζ mediates lung injury induced by diesel exhaust particles.

Caraballo Juan C JC Borcherding Jennifer J Thorne Peter S PS Comellas Alejandro P AP

American journal of respiratory cell and molecular biology 20121206 3

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 prote ...[more]

PMID: 23221045

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Project description:Biodiesel is considered to be a sustainable alternative for fossil fuels such as petroleum-based diesel. However, we still lack knowledge about the impact of biodiesel emissions on humans, as airways and lungs are the primary target organs of inhaled toxicants. This study investigated the effect of exhaust particles from well-characterized rapeseed methyl ester (RME) biodiesel exhaust particles (BDEP) and petro-diesel exhaust particles (DEP) on primary bronchial epithelial cells (PBEC) and macrophages (MQ). The advanced multicellular physiologically relevant bronchial mucosa models were developed using human primary bronchial epithelial cells (PBEC) cultured at air-liquid interface (ALI) in the presence or absence of THP-1 cell-derived macrophages (MQ). The experimental set-up used for BDEP and DEP exposures (18 µg/cm2 and 36 µg/cm2) as well as the corresponding control exposures were PBEC-ALI, MQ-ALI, and PBEC co-cultured with MQ (PBEC-ALI/MQ). Following exposure to both BDEP and DEP, reactive oxygen species as well as the stress protein heat shock protein 60 were upregulated in PBEC-ALI and MQ-ALI. Expression of both pro-inflammatory (M1: CD86) and repair (M2: CD206) macrophage polarization markers was increased in MQ-ALI after both BDEP and DEP exposures. Phagocytosis activity of MQ and the phagocytosis receptors CD35 and CD64 were downregulated, whereas CD36 was upregulated in MQ-ALI. Increased transcript and secreted protein levels of CXCL8, as well as IL-6 and TNF-α, were detected following both BDEP and DEP exposure at both doses in PBEC-ALI. Furthermore, the cyclooxygenase-2 (COX-2) pathway, COX-2-mediated histone phosphorylation and DNA damage were all increased in PBEC-ALI following exposure to both doses of BDEP and DEP. Valdecoxib, a COX-2 inhibitor, reduced the level of prostaglandin E2, histone phosphorylation, and DNA damage in PBEC-ALI following exposure to both concentrations of BDEP and DEP. Using physiologically relevant multicellular human lung mucosa models with human primary bronchial epithelial cells and macrophages, we found BDEP and DEP to induce comparable levels of oxidative stress, inflammatory response, and impairment of phagocytosis. The use of a renewable carbon-neutral biodiesel fuel does not appear to be more favorable than conventional petroleum-based alternative, as regards of its potential for adverse health effects.

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Protein kinase C-? mediates lung injury induced by diesel exhaust particles.

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Protein kinase C-ζ mediates lung injury induced by diesel exhaust particles.

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