Role of CFTR in migration of airway epithelial cells

Abstract

The role of CFTR in airway epithelial wound healing was assessed with Calu‐3 and NHBE airway epithelial cells in real time by measuring changes in impedance (Z) as cells migrated onto the surface of an electrode to close a wound in the epithelium. Inhibition of CFTR activity with CFTRinh‐172 slowed the rate of wound closure (time to reestablish initial Z) in Calu‐3 cells (30 μM) by 6.2 hours compared to control (serum free media, 1 μg/ml EGF, DMSO), and in NHBE cells (20 μM) by 10.0 hours compared to control (serum free media, DMSO). A CFTR specific effect on cell migration was verified in Calu‐3 cells by constitutive expression of CFTR specific shRNA, which resulted in >99% reduction of CFTR transcript. Silencing CFTR in Calu‐3 cells delayed wound closure by 24.3 hours compared to ALTER shRNA expressing and wild type Calu‐3 cells. Replacement of Cl− ions with SO4− and gluconate in the media during Calu‐3 cell migration had no effect on cell migration rate. However, reduction of [HCO3−] from 26 mM to 5 mM in HEPES buffered CO2 gassed media slowed the rate of Calu‐3 cell migration by 3.7 hours, in the absence of a change in intracellular pH. The results of these experiments indicate that functional activity of CFTR is involved in Calu‐3 and NHBE cell migration and suggest a role for CFTR in airway epithelial restitution. Further, these results suggest that HCO3− transport mediated by CFTR is necessary for efficient cell migration.