1187. CFTR Function Impacts Proinflammatory Cytokine Expression of Bronchial Epithelial Cells During Pseudomonas aeruginosa and Staphylococcus aureus Infections

Abstract

BackgroundCystic fibrosis (CF) is a genetic disease in which opportunistic respiratory infections are common, particularly with P. aeruginosa and S. aureus. It has been suggested that dysfunction in the cystic fibrosis transmembrane conductance regulator (CFTR) could impact host immune response to these infections. The aim of this study was to determine if dysfunction in the CFTR gene could impact host cell death and the expression of proinflammatory cytokines.MethodsWe used two human bronchial epithelial (HBE) cell lines NuLi-1 and CuFi-1, which were recovered from individuals without and with CF, respectively. THP-1 cells were also differentiated into a macrophage phenotype with 50ng/mL PMA, and 10 µM CFTRinh-172 was used to impair CFTR function in these cells. Laboratory reference strains PAO1 and S. aureus 6538 were used to conduct in vitro infections. Host cell death at various MOIs was evaluated using a neutral red uptake assay, and cytokine expression was measured using ELISAs.ResultsNo differences in THP-1 cell death or cytokine expression were observed for infections with S. aureus 6538 or PAO1 with and without CFTRinh-172. No differences in cell death for infections with the HBE cells and either bacteria were noted. S. aureus 6538 induced higher levels of IL-1β when infecting CuFi-1 cells in comparison to NuLi-1 cells across all MOIs (P < 0.001) and induced higher levels of IL-6 at an MOI of 100 (P < 0.01). S. aureus 6538 also induced higher levels of IL-8 when infecting CuFi-1 cells in comparison to NuLi-1 at MOIs of 1 and 10 (P < 0.05 and P < 0.01, respectively). Meanwhile, PAO1 induced less IL-6 expression when infecting CuFI-1 cells at an MOI of 1 and 10 (P < 0.01 and P < 0.01, respectively). CuFi-1 cells infected with PAO1 had less IL-8 expression in comparison to infected NuLi-1 cells for all MOIs (P < 0.01), but no differences in IL-1β expression were observed when infecting either cell line with PAO1.ConclusionBronchial epithelial cells with and without functional CFTR appear to respond differently to infections with either P. aeruginosa or S. aureus. Further elucidating how various immune response pathways are impacted by CFTR dysfunction may lead to alternative approaches to therapy to reduce morbidity observed among CF patients.Disclosures All Authors: No reported disclosures