In Vitro Modulator Responsiveness of 655 CFTR Variants Found in People With CF

作者：Hermann J. Bihler, Andrey Sivachenko, Linda Millen, Priyanka Bhatt, Amita Thakerar Patel, Justin Chin, Violaine Bailey, Isaac Musisi, André LaPan, Norm Allaire, Joshua Conte, Noah Simon, Amalia Magaret, Karen S. Raraigh, Garry R. Cutting, William R. Skach, Robert J. Bridges, Phil J. Thomas, Martin Mense · 发表于：bioRxiv (Cold Spring Harbor Laboratory) · 年份：2023 · DOI：10.1101/2023.07.07.548159 · 被引用次数：12 · 研究领域：Cystic Fibrosis Research Advances、Advanced biosensing and bioanalysis techniques、Congenital Ear and Nasal Anomalies

Abstract Background In 2017, the US Food and Drug Administration initiated expansion of drug labels for the treatment of cystic fibrosis (CF) to include CF transmembrane conductance regulator (CFTR) gene variants based on in vitro functional studies. This study aims to identify CFTR variants that result in increased chloride (Cl - ) transport function by the CFTR protein after treatment with the CFTR-modulator combination elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA). These data may benefit people with CF (pwCF) who are not currently eligible for modulator therapies. Methods Plasmid DNA encoding 655 CFTR variants and wild-type (WT) CFTR were transfected into Fisher Rat Thyroid cells that do not natively express CFTR. After 24 hours of incubation with control or TEZ and ELX, and acute addition of IVA, CFTR function was assessed using the transepithelial current clamp conductance assay. Each variant’s baseline activity, responsiveness to IVA alone, and responsiveness to the TEZ/ELX/IVA combination were measured in three different laboratories. Western blots were conducted to evaluate CFTR protein maturation and complement the functional data. Results and Conclusions 253 variants not currently approved for CFTR modulator therapy showed low baseline activity (<10% of normal CFTR Cl - transport activity). For 152 of these variants, treatment with ELX/TEZ/IVA improved the Cl - transport activity by ≥10% of normal CFTR function, which is suggestive of clinical benefit. ELX/TEZ/IVA ...