Related Experiment Video
Updated: Jun 13, 2025
Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients
Published on: February 11, 2017
CFTR modulators response of S737F and T465N CFTR variants on patient-derived rectal organoids
Karina Kleinfelder1, Paola Melotti2, Anca Manuela Hristodor2
1Department of Medicine, Division of General Pathology, Cystic Fibrosis Laboratory "D. Lissandrini", University of Verona, 37134, Verona, Italy.
Background:
Predictions based on patient-derived materials of CFTR modulators efficacy have been performed lately in patient-derived cells, extending FDA-approved drugs for CF patients harboring rare variants. Here we developed intestinal organoids from subjects carrying S737F- and T465N-CFTR in trans with null alleles to evaluate their functional impact on CFTR protein function and their restoration upon CFTR modulator treatment. The characterization of S737F-CFTR was performed in two subjects recently assessed in nasal epithelial cells but not in colonoids.
Results:
Our functional analysis (Ussing chamber) confirmed that S737F-CFTR is a mild variant with residual function as investigated in colonoids of patients with S737F/Dele22-24 and S737F/W1282X genotypes. An increase of current upon Elexacaftor/Tezacaftor/Ivacaftor (ETI) treatment was recorded for the former genotype. T465N is a poorly characterized missense variant that strongly impacts CFTR function, as almost no CFTR-mediated anion secretion was registered for T465N/Q39X colonoids. ETI treatment substantially improved CFTR-mediated anion secretion and increased the rescue of mature CFTR expression compared to either untreated colonoids or to dual CFTR modulator therapies.
Conclusions:
Our study confirms the presence of a residual function of the S737F variant and its limited response to CFTR modulators while predicting for the first time the potential clinical benefit of Trikafta® for patients carrying the rare T465N variant.
Insights
This study evaluated rare cystic fibrosis transmembrane conductance regulator (CFTR) variants S737F and T465N using patient-derived organoids. S737F showed mild function, while T465N had minimal function, with both showing potential benefits from CFTR modulator therapies.
Area of Science:
- Biochemistry
- Genetics
- Cell Biology
Background:
- Patient-derived cells are used to predict CFTR modulator efficacy for cystic fibrosis (CF) patients with rare variants.
- Intestinal organoids were developed from subjects with S737F- and T465N-CFTR variants to assess their functional impact and response to modulators.
Purpose of the Study:
- To evaluate the functional impact of S737F- and T465N-CFTR variants using intestinal organoids.
- To assess the restoration of CFTR protein function upon CFTR modulator treatment for these rare variants.
Main Methods:
- Intestinal organoids derived from CF patients carrying specific CFTR variants (S737F, T465N) were utilized.
- Functional analysis was performed using Ussing chamber experiments to measure CFTR-mediated anion secretion.
- The effect of Elexacaftor/Tezacaftor/Ivacaftor (ETI) treatment on CFTR function and protein expression was evaluated.
Main Results:
- The S737F-CFTR variant demonstrated residual function in colonoids, with a measurable current increase upon ETI treatment in S737F/Dele22-24 genotypes.
- The T465N-CFTR variant showed significantly impaired function, with minimal CFTR-mediated anion secretion in T465N/Q39X colonoids.
- ETI treatment substantially improved anion secretion and mature CFTR expression for the T465N variant compared to untreated or dual-therapy conditions.
Conclusions:
- The S737F variant exhibits residual CFTR function with a limited response to current CFTR modulators.
- This study predicts a potential clinical benefit of Trikafta® (ETI) for patients with the rare T465N-CFTR variant, highlighting its therapeutic potential.
