Transient Receptor Potential Ankyrin 1 Channels Modulate Inflammatory Response in Respiratory Cells from Patients with Cystic Fibrosis.

Pseudomonas aeruginosa colonization, prominent inflammation with massive expression of the neutrophil chemokine IL-8 and luminal infiltrates of neutrophils are hallmarks of chronic lung disease in Cystic Fibrosis (CF) patients. The nociceptive Transient Receptor Potential Ankyrin 1 (TRPA1) calcium channels have been recently found involved in non-neurogenic inflammation. Here, we investigated the role of TRPA1 in CF respiratory inflammatory models in vitro. Expression of TRPA1 was evaluated in CF lung tissue sections and cells by immunohistochemistry and by immunofluorescence. Epithelial cell lines (A549, IB3-1, CuFi-1, CFBE41o-) and primary cells from CF patients were utilized to a) check TRPA1 function modulation, by Fura-2 calcium imaging, b) down-modulate TRPA1 function and expression, by pharmacological inhibitors (HC-030031 and A-967079) and siRNA silencing, and c) assess the effect of TRPA1 down-modulation on expression and release of cytokines upon exposure to pro-inflammatory challenges, by qRT-PCR and 27-protein Bioplex assay. TRPA1 channels are expressed in the CF pseudostratified columnar epithelium facing the bronchial lumina exposed to bacteria, where IL-8 is co-expressed. Inhibition of TRPA1 expression results in a relevant reduction of release of several cytokines, including IL-8 and the pro-inflammatory cytokines IL-1β and TNF-α, in CF primary bronchial epithelial cells exposed to P. aeruginosa and to the supernatant of mucopurulent material derived from the chronically infected airways of CF patients. In conclusion, TRPA1 channels are involved in regulating the extent of airway inflammation driven by CF bronchial epithelial cells.