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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.
|Number of pages||10|
|Journal||American Journal of Respiratory and Critical Care Medicine|
|Early online date||25 Mar 2016|
|Publication status||Published - Sep 2016|
- channel activating proteases
- pseudomonas aeruginosa exotoxin
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
R2634PMY: Channel activating proteases (CAPS): identification of novel targets for correcting sodium channel dysfunction in CF
01/08/2009 → …
R2887PMY: Channel Activating Proteases (CAPS): molecular targets for correction of sodium channel dysfunction in airways disease
01/08/2012 → 31/12/2015
Inhibition of protease-epithelial sodium channel singling improves mucociliary function in cystic fibrosis airways.
Lorraine Martin (Invited speaker)27 Oct 2016
Activity: Talk or presentation types › Invited talk