Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627986
Title: Mechanistic studies of small-molecule CFTR modulators
Author: Liu, Jia
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2012
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Abstract:
The cystic fibrosis transmembrane conductance regulator (CFTR) is a CI channel found in the apical membrane of epithelial cells. CFTR activity is tightly controlled by complex regulation. However, CFTR overactivity or loss-of-function mutations in CFTR are both disease causing conditions. The aims of my research were to investigate the mechanisms Of action of small-molecule CFTR modulators that regulate CFTR function. Loop diuretics are inhibitors ofNa+-K+-2Cr-cotranspOlter isofOlm 1 (NKCC1) located in the basolateral membrane of epithelial cells. I demonstrated that loop diuretics also inhibit CFTR cr channels, with lower potency, as open-channel blockers to occlude the CI permeation pathway in both recombinant cells and epithelia. Therefore, loop diuretics inhibit cr secretion both by inhibiting NKCC1 and CFTR in the basolateral and apical membranes, respectively. Like FS08del, AS61E is a CFTR processmg mutation that causes cystic fibrosis. I demonstrated that surface expressed AS61 E-CFTR cr channels have a severe gating defect with shortened mean burst duration and prolonged interburst interval. I also showed that the activity of surface expressed AS61E-CFTR is enhanced by the CFTR potentiator UCcF-8S3 , but not by UCcF-180. These data suggest that UCcF-8S3 is non-specific for FS08del-CFTR. Finally, to target the root cause of the commonest CF mutation, FS08del, I studied a group of dual-acting (corrector-potentiator) small molecules. I demonstrated that EPIX 107813 acts as a CFTR dual-acting modulator to, first, rescue cell surface expression of FS08del-CFTR; second, to partially restore wt-CFTR cr channel gating behaviour to FS08del-CFTR; and third, to improve cell surface thelmal stability of FS08del-CFTR CI channels. Therefore, EPIX 107813 acts as both CFTR corrector and potentiator. In conclusion, this study elucidated the mechanism of action of CFTR modulators and demonstrated their direct interaction with CFTR. Knowledge of how these modulators work will be of value in the development of new therapeutics that target CFTR directly.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.627986  DOI: Not available
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