Altered polarization of PAR-2 signaling during airway epithelial remodeling

Ryan M. Carey; Jenna R. Freund; Benjamin M. Hariri; Nithin D. Adappa; James N. Palmer; Robert J. Lee

To test if ciliated cells autonomously respond to apical PAR-2 stimulation, we measured ciliary beat frequency (CBF) to apical PAR-2 agonists in control and IL-13-treated cultures. We combined CBF measurement with two structurally distinct gap junction inhibitors, steroid-like small molecule inhibitor carbenoxolone (CBX) and peptide inhibitor Gap 27. 28 Control cultures exhibited CBF increases with basolateral but not apical 2FLI; basolateral responses were unaffected by CBX (Fig 7A, B, and G) . IL-13 treated cultures exhibited CBF increase with apical 2FLI (Fig 7C) inhibited by CBX or Gap 27 (Fig 7D-F and G) . Basolateral 2FLI responses were not inhibited by CBX. Apical ATP responses were inhibited by neither CBX nor Gap 27 (Fig 7G) . These data support a model by which well differentiated epithelium (Fig 7H) expresses basolateral PAR-2 within ciliated cells, as CBF increases do not require intercellular gap junction communication ( Fig 7H) . However, dedifferentiation of the epithelium results in apical expression of PAR-2 within nonciliated cells that can increase CBF in ciliated cells only in the presence of functional gap junctions, likely to allow diffusion of calcium and/or IP3 (Fig 7I) .