Abstract

Cystic fibrosis (CF) is a multisystem disease associated with mutations in the gene that encodes the CF transmembrane conductance regulatory (CFTR) protein. The majority of wild-type CFTR and virtually all mutant ΔF508 CFTR are degraded before reaching the cell surface. Certain agents and conditions that increase expression and maturation of CFTR enable the protein to function at the cell surface. We and several research groups have reported that S-nitrosoglutathione (GSNO), a class of endogenous S-nitrosothiols, increases the maturation and function of CFTR in human airway epithelial cells. S-nitrosothiols (SNOs) are endogenous molecules with several cell signaling effects and potential relevance to human lung disease. SNOs are normally present in the human airway and have beneficial effects on lung function. Biochemical evidence suggests that SNOs act on post-translational protein modifications through mechanisms involving S-nitrosylation reactions. S-nitrosylation reactions are increasingly recognized to represent metabolically regulated cell signaling processes. Airway epithelial S-nitrosylation signaling disorders have been observed in a range of diseases, including CF. SNO levels are low in CF patients and normal physiological concentrations are effective in increasing CFTR maturation. The mechanisms by which SNOs improve CFTR expression appear to be novel. However, the precise mechanisms by which SNOs exert their beneficial effects are poorly understood. In the near future, we expect to identify the novel mechanisms by which SNO augments CFTR maturation. This information will be critical for optimizing the design and dosing of SNOs that might be used as CFTR corrector therapies in clinical trials.

Keywords: Cystic fibrosis, CFTR, S-nitrosothiols, S-nitrosylation, molecular therapy.