All ETDs from UAB

Advisory Committee Chair

Eric J Sorscher

Advisory Committee Members

David M Bedwell

Lynn E Dobrunz

Steven M Rowe

Bradley K Yoder

Document Type

Dissertation

Date of Award

2009

Degree Name by School

Doctor of Philosophy (PhD) Heersink School of Medicine

Abstract

Cystic fibrosis (CF) is a lethal genetic disorder leading to pulmonary decline and premature death. The gene responsible for CF, the cystic fibrosis transmembrane conductance regulator (CFTR), serves as a chloride and bicarbonate channel situated at the apical cell surface of epithelia. The discovery of small molecules that augment channel gating of mutant CFTR (so-called `potentiators') represents a major theme of CF research, and offers hope for new therapeutic interventions. High-throughput screening (HTS) provides a means to test millions of agents in an unbiased manner for CFTR potentiating properties. New agents identified by HTS have undergone extensive pre-clinical and clinical testing in CF individuals, and shown substantial progress toward clinical advancement. However, novel strategies are required to better understand CFTR potentiators and their applicability in the clinic. In this thesis, we pursued a detailed understanding of emerging CFTR potentiators with high relevance to therapeutic intervention. We describe a set of mechanistic experiments intended to functionally categorize CFTR potentiators based on their bio-chemical effects on the CFTR regulatory domain (RD), and their activity profiles in cell systems representative of the in vivo environment. Our findings indicate that CFTR potentiators acting independently of RD phosphorylation may be best tailored to rescue cAMP regulation of CFTR carrying the common &deltaF508 mutation. In another series of experiments, we show that quercetin, a novel flavonoid, potentiates CFTR mediated an-ion transport in respiratory epithelia in vitro and in vivo, and may be useful to optimally detect rescue of &deltaF508-CFTR. The present project therefore addresses two questions fundamental to both CFTR biology and CF therapeutic intervention: 1. How can knowledge of CFTR modulator mechanism aid in optimization of emerging CFTR potentiators and advance basic understanding of CFTR biology? 2. How can knowledge of a robust class of CFTR activators, the flavonoids, be used to identify compounds best able to activate and detect surface localized and functional CFTR in human subjects with cystic fibrosis? These findings address the increasingly recognized gap between identification of new therapeutic compounds for CF, and a better understanding of agents most suitable for basic and translational cystic fibrosis research.

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