CFTR mutation abrogates Prevotella regulation of epithelial cell defense against Staphylococcus aureus

Background: The oral anaerobe Prevotella melaninogenica is enriched in the lungs of people with cystic fibrosis (pwCF), yet its functional impact on respiratory tract homeostasis remains incompletely understood. Prior studies identified immune modulatory effects following lung exposure to Prevotella, but the relevance of these findings for CF infections is unknown. Methods: The impact of P. melaninogenica on infection with the CF pathogen Staphylococcus aureus was evaluated using a mouse lung infection model and human respiratory tract cystic fibrosis transmembrane conductance regulator (CFTR) mutant and isogenic wild-type (WT)-corrected CFBE41o- epithelial cells. RNA-sequencing was performed to compare Prevotella-induced signaling programs in WT-corrected versus CFTR mutant cells. Results: P. melaninogenica significantly reduced S. aureus lung infection, which was associated with elevated S. aureus killing by lung neutrophils and impaired S. aureus adherence to epithelial cells. Live or heat-killed Prevotella were sufficient to mediate these effects, which were dependent on the toll-like receptor TLR2. Prevotella impairment of S. aureus adherence also required CFTR function, as this effect was lost in CFTR mutant cells but restored by CFTR modulator therapy. RNA-sequencing identified several antibacterial defense pathways selectively upregulated by Prevotella in WT corrected epithelial cells, correlating with higher IL-8 and IL-6 cytokine production. Conclusions: P. melaninogenica enhanced neutrophil and epithelial defense against S. aureus, but these benefits were lost with CFTR dysfunction. CFTR modulator therapy rescued Prevotella responsiveness in respiratory epithelial cells, highlighting the potential for synergistic effects of host-microbiome interactions and CFTR targeted therapies.