Affiliation:
1. Research Service, Department of Veterans Affairs Medical Center, Omaha 68105; and
2. Pulmonary and Critical Care Medicine Section, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198
Abstract
Hog barn workers have an increased incidence of respiratory tract symptoms and demonstrate an increase in lung inflammatory mediators, including interleukin (IL)-8 and IL-6. Utilizing direct kinase assays for protein kinase C (PKC) activation, we demonstrated that dust from hog confinement facilities, or hog dust extract (HDE), augments PKC activity of human airway epithelial cells in vitro. A 5% dilution of HDE typically stimulates an approximately twofold increase in human bronchial epithelial cell (HBEC) PKC activity compared with control medium-treated cells. This increase in PKC is observed with 15 min of HDE treatment, and kinase activity reaches peak activity by 1–2 h of HDE treatment before returning to baseline PKC levels between 6 and 24 h. The classic PKC inhibitor, calphostin C, blocks HDE-stimulated PKC activity and associated IL-8 and IL-6 release. Desensitization to HDE stimulation of PKC activation does not appear to occur because subsequent exposures to HDE after an initial exposure result in further augmentation of PKC. Detoxification of HDE with polymyxin B to remove endotoxin did not change PKC activation or IL-8 release, suggesting that endotoxin is not solely responsible for HDE augmentation of PKC. These data support the hypothesis that HDE exposure augments HBEC IL-8 and IL-6 release via a PKC-dependent pathway.
Publisher
American Physiological Society
Subject
Physiology (medical),Physiology
Cited by
99 articles.
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