Clinically approved CFTR modulators rescue Nrf2 dysfunction in cystic fibrosis airway epithelia
Dana C. Borcherding, Matthew E. Siefert, Songbai Lin, John Brewington, Hesham Sadek, John P. Clancy, Scott M. Plafker, Assem G. Ziady
Dana C. Borcherding, Matthew E. Siefert, Songbai Lin, John Brewington, Hesham Sadek, John P. Clancy, Scott M. Plafker, Assem G. Ziady
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Research Article Pulmonology

Clinically approved CFTR modulators rescue Nrf2 dysfunction in cystic fibrosis airway epithelia

Abstract

Cystic fibrosis (CF) is a multiorgan progressive genetic disease caused by loss of functional cystic fibrosis transmembrane conductance regulator (CFTR) channel. Previously, we identified a significant dysfunction in CF cells and model mice of the transcription factor nuclear factor E2–related factor-2 (Nrf2), a major regulator of redox balance and inflammatory signaling. Here we report that the approved F508del CFTR correctors VX809 and VX661 recover diminished Nrf2 function and colocalization with CFTR in CF human primary bronchial epithelia by proximity ligation assay, immunoprecipitation, and immunofluorescence, concordant with CFTR correction. F508del CFTR correctors induced Nrf2 nuclear translocation, Nrf2-dependent luciferase activity, and transcriptional activation of target genes. Rescue of Nrf2 function by VX809/VX661 was dependent on significant correction of F508del and was blocked by inhibition of corrected channel function, or high-level shRNA knockdown of CFTR or F508del CFTR. Mechanistically, F508del CFTR modulation restored Nrf2 phosphorylation and its interaction with the coactivator CREB-binding protein (CBP). Our findings demonstrate that sufficient modulation of F508del CFTR function corrects Nrf2 dysfunction in CF.

Authors

Dana C. Borcherding, Matthew E. Siefert, Songbai Lin, John Brewington, Hesham Sadek, John P. Clancy, Scott M. Plafker, Assem G. Ziady

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Figure 7

Inhibition of CFTR function blocks CFTR modulator–induced expression of Nrf2 target genes.

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Inhibition of CFTR function blocks CFTR modulator–induced expression of ...
(A) Primary CFhBE cells were incubated with vehicle (DMSO) control or 1 μM VX661 and/or CFTRinh-172 (Inh172) for 48 hours. (B and C) Primary NhBE (B) or CFhBE (C) cells were treated with DMSO control or the indicated doses of VX661 and/or GlyH-101 for 72 hours. Gene expression of Nrf2-activated genes (HMOX1 and NQO1) was determined by real-time qPCR. Gene expression is expressed as fold changes versus control cells (DMSO control, Inh172, or GlyH-101 alone), and was calculated from cycle threshold and normalization to the control gene, 18S rRNA. Data for 3–6 independent experiments from 3 CF and 3 non-CF donors with 3–4 replicates per treatment per donor are expressed as box-and-whisker plots. Horizontal bars indicate the median, box borders indicate 25th and 75th percentiles, and whiskers indicate 5th and 95th percentiles. *P < 0.05, **P < 0.01, ***P < 0.001 by mixed-effects ANOVA with Dunnett’s multiple-comparisons test.