Inhibition of Protease–Epithelial Sodium Channel Signaling Improves Mucociliary Function in Cystic Fibrosis Airways

James A. Reihill, Brian Walker, Robert A. Hamilton, Timothy E. G. Ferguson, J. Stuart Elborn, M Jackson Stutts, Brian J Harvey, Vinciane Saint-Criq, Siobhan M Hendrick, S. Lorraine Martin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)
182 Downloads (Pure)

Abstract

Rationale: In cystic fibrosis (CF) a reduction in airway surface liquid (ASL) height
compromises mucociliary clearance, favoring mucus plugging and chronic bacterial infection. Inhibitors of ENaC have therapeutic potential in CF airways to reduce the hyperstimulated sodium and fluid absorption to levels which can restore airways hydration.

Objectives: To determine whether a novel compound (QUB-TL1) designed to inhibit protease/ENaC signaling in CF airways restores ASL volume and mucociliary function.

Methods: Protease activity was measured using fluorogenic activity assays. Differentiated primary airway epithelial cell cultures (F508del homozygotes) were used to determined ENaC activity (Ussing chamber recordings), ASL height (confocal microscopy) and mucociliary function (by tracking the surface flow of apically applied microbeads). Cell toxicity was measured by LDH assay.

Measurements and Results: QUB-TL1 inhibits extracellularly-located CAPs, including prostasin, matriptase and furin, the activities of which are observed at excessive levels at the apical surface of CF airway epithelial cells (AECs). QUB-TL1-mediated CAPs inhibition results in diminished ENaC-mediated Na+ absorption in CF AECs due to internalization of a prominent pool of cleaved (active) ENaCγ from the cell surface. Importantly, diminished ENaC activity correlates with improved airway hydration status and mucociliary clearance. We further demonstrate QUB-TL1-mediated furin inhibition, which is in contrast to other serine protease inhibitors (camostat mesylate and aprotinin), affords protection against neutrophil elastase-mediated ENaC activation and Pseudomonas aeruginosa exotoxin A induced cell death.

Conclusions: QUB-TL1 corrects aberrant CAP activities providing a mechanism to delay or prevent the development of CF lung disease in a manner independent of CFTR mutation.
Original languageEnglish
Pages (from-to)701-710
Number of pages10
JournalAmerican Journal of Respiratory and Critical Care Medicine
Volume194
Issue number6
Early online date25 Mar 2016
DOIs
Publication statusPublished - Sept 2016

Keywords

  • channel activating proteases
  • prostasin
  • furin
  • pseudomonas aeruginosa exotoxin

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology
  • General Medicine

Fingerprint

Dive into the research topics of 'Inhibition of Protease–Epithelial Sodium Channel Signaling Improves Mucociliary Function in Cystic Fibrosis Airways'. Together they form a unique fingerprint.

Cite this