Infection with Prevotella nigrescens induces TLR2 signalling and low levels of p65 mediated inflammation in Cystic Fibrosis bronchial epithelial cells

ABSTRACT Prevotella spp. are frequently identified in Cystic Fibrosis sputum. This study examined whether infection with Prevotella nigrescens, a frequently identified member of this species, contributes to inflammation in CF bronchial epithelial cells through activation of TLR- and NF-κB signalling pathways. CFBE41o- cells were infected with either P.nigrescens or Pseudomonas aeruginosa and incubated under anaerobic conditions for 4 h. P.nigrescens activated TLR2 signalling but not TLR4 signalling while P.aeruginosa activated TLR4 signalling with a lesser effect on TLR2. P.aeruginosa induced significant IκBα phosphorylation 10 min post infection with a return to control levels by 30 min post infection. A significant induction in nuclear p65 DNA binding was observed at 2 h post infection. In contrast, infection with P.nigrescens induced phosphorylation of IκBα 120 min post infection, with significant induction in nuclear p65 DNA binding at 4 h post infection only. Cytokine gene and protein responses were lower for P.nigrescens compared to P.aeruginosa. This study demonstrates the ability of a clinical P.nigrescens isolate to provoke a delayed NF-κB(p65) driven response through induction in TLR2 signalling and activation of sustained levels of IKKα.