cAMP-dependent protein kinase activation decreases cytokine release in bronchial epithelial cells.
Wyatt TA; Poole JA; Nordgren TM; DeVasure JM; Heires AJ; Bailey KL; Romberger DJ
Am J Physiol, Lung Cell Mol Physiol 2014 Oct; 307(8):L643-L651
Lung injury caused by inhalation of dust from swine-concentrated animal-feeding operations (CAFO) involves the release of inflammatory cytokine interleukin 8 (IL-8), which is mediated by protein kinase C-e (PKC-e) in airway epithelial cells. Once activated by CAFO dust, PKC-e is responsible for slowing cilia beating and reducing cell migration for wound repair. Conversely, the cAMP-dependent protein kinase (PKA) stimulates contrasting effects, such as increased cilia beating and an acceleration of cell migration for wound repair. We hypothesized that a bidirectional mechanism involving PKA and PKC regulates epithelial airway inflammatory responses. To test this hypothesis, primary human bronchial epithelial cells and BEAS-2B cells were treated with hog dust extract (HDE) in the presence or absence of cAMP. PKC-e activity was significantly reduced in cells that were pretreated for 1 h with 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) before exposure to HDE (P < 0.05). HDE-induced IL-6, and IL-8 release was significantly lower in cells that were pretreated with 8-Br-cAMP (P < 0.05). To exclude exchange protein activated by cAMP (EPAC) involvement, cells were pretreated with either 8-Br-cAMP or 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (8-CPT-2Me-cAMP) (EPAC agonist). 8-CPT-2Me-cAMP did not activate PKA and did not reduce HDE-stimulated IL-6 release. In contrast, 8-Br-cAMP decreased HDE-stimulated tumor necrosis factor (TNF)-a-converting enzyme (TACE; ADAM-17) activity and subsequent TNF-a release (P < 0.001). 8-Br-cAMP also blocked HDE-stimulated IL-6 and keratinocyte-derived chemokine release in precision-cut mouse lung slices (P < 0.05). These data show bidirectional regulation of PKC-e via a PKA-mediated inhibition of TACE activity resulting in reduced PKC-e-mediated release of IL-6 and IL-8.
Lung; Injuries; Dusts; Dust-exposure; Dust-inhalation; Dust-particles; Respiration; Respiratory-infections; Respiratory-system-disorders; Pulmonary-system; Pulmonary-system-disorders; Pulmonary-function; Agriculture; Animals; Cell-function; Cellular-function; Organic-compounds;
Author Keywords: lung; cytokine; PKC -3; PKA; organic dust
T. Wyatt, Dept. of Environmental, Agricultural, and Occupational Health, College of Public Health, Univ. of Nebraska Medical Center, Omaha, NE 68198-5910
Grant; Cooperative Agreement
Grant-Number-R01-OH-008539; Cooperative-Agreement-Number-U54-OH-010162; M122014
Agriculture, Forestry and Fishing
American Journal of Physiology: Lung Cellular and Molecular Physiology
University of Nebraska Medical Center, Omaha, Nebraska