Introduction: Cystic Fibrosis (CF) is a genetic disease due to loss-of-function mutations of the CFTR channel. F508del is the most frequent mutation (70% of alleles in Italy), while other mutations have much lower frequency. Among them, G85E (0.4% frequency globally, 1.13% in Italy) emerges as a mutation characterized by a severe CFTR folding and trafficking defect. Methods: To investigate the pharmacological responsiveness of the G85E-CFTR variant, we performed a functional and biochemical characterization in heterologous expression systems and ex vivo models based on patient-derived human nasal epithelial cells (HNEC). Results: Our study demonstrated that treatment of primary airway cells with elexacaftor and tezacaftor causes a significant (although modest) rescue of CFTR function, that reaches 15%–25% of the activity measured in non-CF epithelia. A detrimental effect of chronic treatment with ivacaftor, further limiting G85E rescue, was also observed. A higher rescue of CFTR function, up to 25%–35% of the normal CFTR activity, with no evidence of negative effects upon chronic potentiator treatment, can be achieved by combining elexacaftor with ARN23765, a novel type 1 corrector endowed with very high potency. Importantly, dose-response relationships suggest that G85E might alter the binding of type 1 correctors, possibly affecting their affinity for the target. Discussion: In conclusion, our studies suggest that novel combinations of modulators, endowed with higher efficacy leading to increased rescue of G85E-CFTR, are needed to improve the clinical benefit in patients for this variant.

Pharmacological rescue of the G85E CFTR variant by preclinical and approved modulators

Tomati, Valeria;Capurro, Valeria;Pastorino, Cristina;Sondo, Elvira;Lena, Mariateresa;Cresta, Federico;Zara, Federico;Bandiera, Tiziano;Bocciardi, Renata;Castellani, Carlo;Pedemonte, Nicoletta
2024-01-01

Abstract

Introduction: Cystic Fibrosis (CF) is a genetic disease due to loss-of-function mutations of the CFTR channel. F508del is the most frequent mutation (70% of alleles in Italy), while other mutations have much lower frequency. Among them, G85E (0.4% frequency globally, 1.13% in Italy) emerges as a mutation characterized by a severe CFTR folding and trafficking defect. Methods: To investigate the pharmacological responsiveness of the G85E-CFTR variant, we performed a functional and biochemical characterization in heterologous expression systems and ex vivo models based on patient-derived human nasal epithelial cells (HNEC). Results: Our study demonstrated that treatment of primary airway cells with elexacaftor and tezacaftor causes a significant (although modest) rescue of CFTR function, that reaches 15%–25% of the activity measured in non-CF epithelia. A detrimental effect of chronic treatment with ivacaftor, further limiting G85E rescue, was also observed. A higher rescue of CFTR function, up to 25%–35% of the normal CFTR activity, with no evidence of negative effects upon chronic potentiator treatment, can be achieved by combining elexacaftor with ARN23765, a novel type 1 corrector endowed with very high potency. Importantly, dose-response relationships suggest that G85E might alter the binding of type 1 correctors, possibly affecting their affinity for the target. Discussion: In conclusion, our studies suggest that novel combinations of modulators, endowed with higher efficacy leading to increased rescue of G85E-CFTR, are needed to improve the clinical benefit in patients for this variant.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/1234435
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