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Effect of apical chloride concentration on the measurement of responses to CFTR modulation in airway epithelia cultured from nasal brushings.

ABSTRACT: INTRODUCTION:One method for assessing the in vitro response to CFTR-modulating compounds is by analysis of epithelial monolayers in an Ussing chamber, where the apical and basolateral surfaces are isolated and the potential difference, short-circuit current, and transepithelial resistance can be monitored. The effect of a chloride ion gradient across airway epithelia on transepithelial chloride transport and the magnitude of CFTR modulator efficacy were examined. METHODS:CFTR-mediated changes in the potential difference and transepithelial currents of primary human nasal epithelial cell cultures were quantified in Ussing chambers with either symmetrical solutions or reduced chloride solutions in the apical chamber. CFTR activity in homozygous F508del CFTR epithelia was rescued by treatment with VX-661, C4/C18, 4-phenylbutyrate (4-PBA) for 24 hr at 37°C or by incubation at 29°C for 48 hr. RESULTS:Imposing a chloride gradient increased CFTR-mediated and CaCC-mediated ion transport. Treatment of F508del CFTR homozygous cells with CFTR modulating compounds increased CFTR activity, which was significantly more evident in the presence of a chloride gradient. This observation was recapitulated with temperature-mediated F508del CFTR correction. CONCLUSIONS:Imposing a chloride gradient during Ussing chamber measurements resulted in increased CFTR-mediated ion transport in expanded non-CF and F508del CFTR homozygous epithelia. In F508del CFTR homozygous epithelia, the magnitude of response to CFTR modulating compounds or low temperature was greater when assayed with a chloride gradient compared to symmetrical chloride, resulting in an apparent increase in measured efficacy. Future work may direct which methodologies utilized to quantify CFTR modulator response in vitro are most appropriate for the estimation of in vivo efficacy.

SUBMITTER: Bratcher PE

PROVIDER: S-EPMC7547589 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Effect of apical chloride concentration on the measurement of responses to CFTR modulation in airway epithelia cultured from nasal brushings.

Bratcher Preston E PE Yadav Sangya S Shaughnessy Ciaran A CA Thornell Ian M IM Zeitlin Pamela L PL

Physiological reports 20201001 19

<h4>Introduction</h4>One method for assessing the in vitro response to CFTR-modulating compounds is by analysis of epithelial monolayers in an Ussing chamber, where the apical and basolateral surfaces are isolated and the potential difference, short-circuit current, and transepithelial resistance can be monitored. The effect of a chloride ion gradient across airway epithelia on transepithelial chloride transport and the magnitude of CFTR modulator efficacy were examined.<h4>Methods</h4>CFTR-medi ...[more]

PMID: 33038073

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Project description:BackgroundDefinite diagnosis of sporadic Creutzfeldt-Jakob disease in living patients remains a challenge. A test that detects the specific marker for Creutzfeldt-Jakob disease, the prion protein (PrP(CJD)), by means of real-time quaking-induced conversion (RT-QuIC) testing of cerebrospinal fluid has a sensitivity of 80 to 90% for the diagnosis of sporadic Creutzfeldt-Jakob disease. We have assessed the accuracy of RT-QuIC analysis of nasal brushings from olfactory epithelium in diagnosing sporadic Creutzfeldt-Jakob disease in living patients.MethodsWe collected olfactory epithelium brushings and cerebrospinal fluid samples from patients with and patients without sporadic Creutzfeldt-Jakob disease and tested them using RT-QuIC, an ultrasensitive, multiwell plate-based fluorescence assay involving PrP(CJD)-seeded polymerization of recombinant PrP into amyloid fibrils.ResultsThe RT-QuIC assays seeded with nasal brushings were positive in 30 of 31 patients with Creutzfeldt-Jakob disease (15 of 15 with definite sporadic Creutzfeldt-Jakob disease, 13 of 14 with probable sporadic Creutzfeldt-Jakob disease, and 2 of 2 with inherited Creutzfeldt-Jakob disease) but were negative in 43 of 43 patients without Creutzfeldt-Jakob disease, indicating a sensitivity of 97% (95% confidence interval [CI], 82 to 100) and specificity of 100% (95% CI, 90 to 100) for the detection of Creutzfeldt-Jakob disease. By comparison, testing of cerebrospinal fluid samples from the same group of patients had a sensitivity of 77% (95% CI, 57 to 89) and a specificity of 100% (95% CI, 90 to 100). Nasal brushings elicited stronger and faster RT-QuIC responses than cerebrospinal fluid (P<0.001 for the between-group comparison of strength of response). Individual brushings contained approximately 10(5) to 10(7) prion seeds, at concentrations several logs10 greater than in cerebrospinal fluid.ConclusionsIn this preliminary study, RT-QuIC testing of olfactory epithelium samples obtained from nasal brushings was accurate in diagnosing Creutzfeldt-Jakob disease and indicated substantial prion seeding activity lining the nasal vault. (Funded by the Intramural Research Program of the National Institute of Allergy and Infectious Diseases and others.).

Dataset Information

Effect of apical chloride concentration on the measurement of responses to CFTR modulation in airway epithelia cultured from nasal brushings.

Publications

Effect of apical chloride concentration on the measurement of responses to CFTR modulation in airway epithelia cultured from nasal brushings.

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