Stimulation of cystic fibrosis transmembrane conductance regulator-dependent short-circuit currents across DeltaF508 murine intestines.

Abstract

The cystic fibrosis transmembrane conductance regulator (CFTR) can be activated by pharmacological manipulation of the protein kinase A pathway in cell lines. Our goals were to stimulate wild-type CFTR in murine intestines via isoform-specific phosphodiesterase inhibition or protein kinase A activation and to apply the optimal stimulus to activate chloride secretion from homozygous DeltaF508 jejunum. The response of T84 cells and sections of murine intestine to various inhibitors and activators was examined by Ussing chamber experiments. Maximal chloride secretion can be activated in T84 cells with application of class III phosphodiesterase inhibitors and in wild-type murine intestines with class I or III phosphodiesterase inhibitors or with activators of type II protein kinase A. Chloride secretion can be stimulated from homozygous DeltaF508 murine jejunum using a mixture of inhibitors and activators. DeltaF508 CFTR can be activated to levels 4% of wild-type when the combination of protein kinase A type II activators and phosphodiesterase class I and III inhibitors are used in murine jejunum. This result suggests that partial CFTR-mediated electrolyte transport can be restored in DeltaF508 murine jejunum by application of specific pharmacological agents.