title: Feedlot dust stimulation of interleukin-6 and -8 requires protein kinase Cepsilon in human bronchial epithelial cells.
abstract: Individuals exposed to dusts from concentrated animal feeding operations report increased numbers of respiratory tract symptoms, and bronchoalveolar lavage samples from such individuals demonstrate elevated lung inflammatory mediators, including interleukin (IL)-8 and IL-6. We previously found that exposure of bronchial epithelial cells to hog barn dusts resulted in a protein kinase C (PKC)-dependent increase in IL-6 and IL-8 release. We hypothesized that cattle feedlot dusts would also generate bronchial epithelial interleukin release in vitro. To test this, we used interleukin ELISAs and direct PKC isoform assays. We found that a dust extract from cattle feedlots [feedlot dust extract (FLDE)] augments PKC activity of human bronchial epithelial cells in vitro. A 5-10% dilution of FLDE stimulated a significant release of IL-6 and IL-8 at 6-24 h in a PKC-dependent manner vs. control medium-treated cells. An increase in PKCalpha activity was observed with 1 h of FLDE treatment, and PKCepsilon activity was elevated at 6 h of FLDE exposure. The PKCalpha inhibitor, Gö-6976, did not inhibit FLDE-stimulated IL-8 and IL-6 release. However, the PKCepsilon inhibitor, Ro 31-8220, effectively inhibited FLDE-stimulated IL-8 and IL-6 release. Inhibition of FLDE-stimulated IL-6 and IL-8 was confirmed in a dominant-negative PKCepsilon-expressing BEAS-2B cell line but not observed in a PKCalpha dominant negative BEAS-2B cell line. These data support the hypothesis that FLDE exposure stimulates bronchial epithelial IL-8 and IL-6 release via a PKCepsilon-dependent pathway.
authors.affiliation: Pulmonary and Critical Care Medicine Section, Department of Internal Medicine, Omaha, NE, USA.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Wyatt
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Slager
authors.forename: Jane
authors.initials: J
authors.lastname: Devasure
authors.forename: Brent W
authors.initials: BW
authors.lastname: Auvermann
authors.forename: Michael L
authors.initials: ML
authors.lastname: Mulhern
authors.forename: Susanna
authors.initials: S
authors.lastname: Von Essen
authors.forename: Tracy
authors.initials: T
authors.lastname: Mathisen
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Floreani
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Romberger
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001980:Bronchi / Q000166:cytology*; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004391:Dust; D004789:Enzyme Activation / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D051744:Protein Kinase C-epsilon / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000166:cytology / Q000378:metabolism*; D013997:Time Factors
chemical_list: D004391:Dust; D004791:Enzyme Inhibitors; D015850:Interleukin-6; D016209:Interleukin-8; D051744:Protein Kinase C-epsilon