Hog confinement dust enhances neutrophil adherence to airway epithelial cells.
Heires AJ; Hilger MA; Wyatt TA; Von Essen SG; Romberger DJ
Am J Respir Crit Care Med 2009 Apr; 179(Meeting Abstracts):A2197
Rationale: Persons exposed to swine confinement facilities have evidence of neutrophilic airway inflammation. We previously reported that dust extract from swine facilities is a potent stimulant of interleukin-8 (IL-8) from airway epithelial cells in vitro that is mediated by protein kinase C (PKC) isoforms alpha and epsilon. We hypothesized that dust extract also modulates the ability of neutrophils to adhere to airway epithelium. Methods: Confluent human bronchial epithelial cell monolayers (BEAS-2B) were pre-treated with one of the following agents: anti-ICAM-1 neutralizing antibody or PKC-a or -e specific inhibitors (Gö6976, RO-318220, respectively) before being exposed to 5% hog confinement dust extract (HDE) for up to 24h. Two epithelial cell lines with inactive PKCa or PKCe (PKCaDN, PKCeDN respectively) were also used. Fresh blood neutrophils (PMN, 300x105/well) labeled with the fluorescent dye calcein-AM were allowed to adhere to the BEAS-2B for 30 minutes. Adherent cells were quantified photometrically. Six wells were averaged for each condition; experiments were repeated 3 times. Multiple comparisons were analyzed using ANOVA with Bonferroni posttest. Results: Adhesion of PMN to BEAS-2B cells treated with HDE was increased in both a time- and dose-dependent fashion. Inhibition of BEAS-2B PKCa using Gö6976 or the PKCaDN cell line resulted in a 55.4%, and 51.4% reduction in PMN adherence, respectively (p<.01). Likewise, PKCe inhibition by RO-318220 or PKCeDN cells resulted in a 55.8% and 58.1% decrease, respectively (p<.05). Neutralizing antibody blockade of ICAM-1 (1:50 dilution) reduced PMN adherence dose-responsively (68.63%, p<.01). Conclusions: Dust extract mediates PMN adherence predominantly by influencing the epithelium and involves PKC isoforms a and e and ICAM-1.
Biological-factors; Cell-biology; Cell-function; Dust-exposure; Dust-inhalation; Exposure-assessment; Exposure-levels; Exposure-methods; Inhalation-studies; Lung-disorders; Lung-function; Lung-irritants; Mathematical-models; Physiological-effects; Physiological-measurements; Pulmonary-system-disorders; Respiratory-hypersensitivity; Respiratory-irritants; Respiratory-system-disorders; Statistical-analysis; Work-environment; Workplace-studies
Agriculture, Forestry and Fishing
American Journal of Respiratory and Critical Care Medicine
University of Nebraska Medical Center, Omaha, Nebraska