Toll-Like Receptor Agonists Modulate Wound Regeneration in Airway Epithelial Cells.

ABSTRACT

BACKGROUND: Impaired regeneration of airway epithelium may lead to persistence of inflammation and remodelling. Regeneration of injured epithelium is a complex phenomenon and the role of toll-like receptors (TLRs) in the stimulation of respiratory virus products in this process has not been established. OBJECTIVE: This study was undertaken to test the hypothesis that the wound repair process in airway epithelium is modulated by microbial products via toll-like receptors. METHODS: Injured and not-injured bronchial epithelial cells (ECs) (BEAS-2B line) were incubated with the TLR agonists poly(IC), lipopolisacharide (LPS), allergen Der p1, and supernatants from virus-infected epithelial cells, either alone or in combination with TLR inhibitors. Regeneration and immune response in injured and not-injured cells were studied. RESULTS: Addition of either poly(IC) or LPS to ECs induced a marked inhibition of wound repair. Supernatants from RV1b-infected cells also decreased regeneration. Preincubation of injured and not-injured ECs with TLR inhibitors decreased LPS and poly(IC)-induced repair inhibition. TGF-ß and RANTES mRNA expression was higher in injured ECs and IFN-α, IFN-ß, IL-8, and VEGF mRNA expression was lower in damaged epithelium as compared to not-injured. Stimulation with poly(IC) increased IFN-α and IFN-ß mRNA expression in injured cells, and LPS stimulation decreased interferons mRNA expression both in not-injured and injured ECs. CONCLUSION: Regeneration of the airway epithelium is modulated by microbial products via toll-like receptors.