# Functional CFTR may be required for Prevotella melaninogenica regulation of epithelial cell defense against Staphylococcus aureus

## TL;DR

This study shows that Prevotella melaninogenica helps fight Staphylococcus aureus infections in the lungs, but only when the CFTR protein is functioning properly.

## Contribution

The study reveals that functional CFTR is essential for Prevotella melaninogenica to regulate epithelial defenses against S. aureus in cystic fibrosis.

## Key findings

- Prevotella melaninogenica reduces S. aureus lung infection by enhancing neutrophil killing and reducing bacterial adherence.
- Functional CFTR is required for Prevotella melaninogenica to impair S. aureus adherence to epithelial cells.
- CFTR modulators restore Prevotella melaninogenica-induced defenses in CFTR-mutant cells.

## Abstract

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.

The impact of P. melaninogenica on infection with the CF pathogen Staphylococcus aureus was evaluated using a mouse lung infection model and by measuring S. aureus adherence to human respiratory tract cystic fibrosis transmembrane conductance regulator (CFTR) mutant and isogenic wild-type (WT)-corrected CFBE41o-epithelial cells. Epithelial cytokine/chemokine secretion and RNA-sequencing were performed to compare P. melaninogenica-induced signaling programs in WT-corrected versus CFTR mutant cells.

P. melaninogenica significantly reduced S. aureus lung infection, associated with elevated S. aureus killing by lung neutrophils and impaired S. aureus adherence to epithelial cells. Live or killed P. melaninogenica were sufficient to mediate these effects, which were dependent on TLR2. P. melaninogenica impairment of S. aureus adherence required functional CFTR, as this effect was lost in CFTR mutant cells but restored by CFTR modulators. RNA-sequencing identified several antibacterial defense pathways selectively upregulated by P. melaninogenica in WT corrected epithelial cells, correlating with higher IL-8 and IL-6 cytokine production.

P. melaninogenica enhanced neutrophil and epithelial defense against S. aureus, but the benefits of epithelial cell regulation by P. melaninogenica were lost with CFTR dysfunction. CFTR modulators rescued P. melaninogenica responsiveness in epithelial cells, highlighting the potential for synergistic effects of hostmicrobiome interactions and CFTR targeted therapies.