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Mention K, Cavusoglu-Doran K, Joynt AT, Santos L, Sanz D, Eastman AC, Merlo C, Langfelder-Schwind E, Scallan MF, Farinha CM, Cutting GR, Sharma N, Harrison PT. Use of adenine base editing and homology-independent targeted integration strategies to correct the cystic fibrosis causing variant, W1282X. Hum Mol Genet 2023; 32:3237-3248. [PMID: 37649273 PMCID: PMC10656707 DOI: 10.1093/hmg/ddad143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/21/2023] [Accepted: 08/12/2023] [Indexed: 09/01/2023] Open
Abstract
Small molecule drugs known as modulators can treat ~90% of people with cystic fibrosis (CF), but do not work for premature termination codon variants such as W1282X (c.3846G>A). Here we evaluated two gene editing strategies, Adenine Base Editing (ABE) to correct W1282X, and Homology-Independent Targeted Integration (HITI) of a CFTR superexon comprising exons 23-27 (SE23-27) to enable expression of a CFTR mRNA without W1282X. In Flp-In-293 cells stably expressing a CFTR expression minigene bearing W1282X, ABE corrected 24% of W1282X alleles, rescued CFTR mRNA from nonsense mediated decay and restored protein expression. However, bystander editing at the adjacent adenine (c.3847A>G), caused an amino acid change (R1283G) that affects CFTR maturation and ablates ion channel activity. In primary human nasal epithelial cells homozygous for W1282X, ABE corrected 27% of alleles, but with a notably lower level of bystander editing, and CFTR channel function was restored to 16% of wild-type levels. Using the HITI approach, correct integration of a SE23-27 in intron 22 of the CFTR locus in 16HBEge W1282X cells was detected in 5.8% of alleles, resulting in 7.8% of CFTR transcripts containing the SE23-27 sequence. Analysis of a clonal line homozygous for the HITI-SE23-27 produced full-length mature protein and restored CFTR anion channel activity to 10% of wild-type levels, which could be increased three-fold upon treatment with the triple combination of CF modulators. Overall, these data demonstrate two different editing strategies can successfully correct W1282X, the second most common class I variant, with a concomitant restoration of CFTR function.
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Affiliation(s)
- Karen Mention
- Department of Physiology, University College Cork, College Road, Cork, T12 K8AF, Ireland
- School of Microbiology, University College Cork, College Road, Cork, T12 K8AF, Ireland
| | - Kader Cavusoglu-Doran
- Department of Physiology, University College Cork, College Road, Cork, T12 K8AF, Ireland
| | - Anya T Joynt
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, United States
| | - Lúcia Santos
- Department of Physiology, University College Cork, College Road, Cork, T12 K8AF, Ireland
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisboa, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal
| | - David Sanz
- Department of Physiology, University College Cork, College Road, Cork, T12 K8AF, Ireland
| | - Alice C Eastman
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, United States
| | - Christian Merlo
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, 1800 Orleans St, Baltimore, MD 21287, United States
| | - Elinor Langfelder-Schwind
- The Cystic Fibrosis Center, Lenox Hill Hospital, 100 E. 77th Street, 4E, New York, NY 10075, United States
| | - Martina F Scallan
- School of Microbiology, University College Cork, College Road, Cork, T12 K8AF, Ireland
| | - Carlos M Farinha
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisboa, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal
| | - Garry R Cutting
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, United States
| | - Neeraj Sharma
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, United States
| | - Patrick T Harrison
- Department of Physiology, University College Cork, College Road, Cork, T12 K8AF, Ireland
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Graeber SY, Mall MA. The future of cystic fibrosis treatment: from disease mechanisms to novel therapeutic approaches. Lancet 2023; 402:1185-1198. [PMID: 37699417 DOI: 10.1016/s0140-6736(23)01608-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/23/2023] [Accepted: 07/31/2023] [Indexed: 09/14/2023]
Abstract
With the 2019 breakthrough in the development of highly effective modulator therapy providing unprecedented clinical benefits for over 90% of patients with cystic fibrosis who are genetically eligible for treatment, this rare disease has become a front runner of transformative molecular therapy. This success is based on fundamental research, which led to the identification of the disease-causing CFTR gene and our subsequent understanding of the disease mechanisms underlying the pathogenesis of cystic fibrosis, working together with a continuously evolving clinical research and drug development pipeline. In this Series paper, we focus on advances since 2018, and remaining knowledge gaps in our understanding of the molecular mechanisms of CFTR dysfunction in the airway epithelium and their links to mucus dysfunction, impaired host defences, airway infection, and chronic inflammation of the lungs of people with cystic fibrosis. We review progress in (and the remaining obstacles to) pharmacological approaches to rescue CFTR function, and novel strategies for improved symptomatic therapies for cystic fibrosis, including how these might be applicable to common lung diseases, such as bronchiectasis and chronic obstructive pulmonary disease. Finally, we discuss the promise of genetic therapies and gene editing approaches to restore CFTR function in the lungs of all patients with cystic fibrosis independent of their CFTR genotype, and the unprecedented opportunities to transform cystic fibrosis from a fatal disease to a treatable and potentially curable one.
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Affiliation(s)
- Simon Y Graeber
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Cystic Fibrosis Center, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; German Center for Lung Research, associated partner site, Berlin, Germany; Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Marcus A Mall
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Cystic Fibrosis Center, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; German Center for Lung Research, associated partner site, Berlin, Germany; Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany.
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Fundamental and translational research in Cystic Fibrosis - why we still need it. J Cyst Fibros 2023; 22 Suppl 1:S1-S4. [PMID: 36577595 DOI: 10.1016/j.jcf.2022.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/27/2022]
Abstract
Clinical treatments for cystic fibrosis (CF) underwent significant changes in the last decade as therapies targeting the basic defect in the CFTR protein were approved. Significant scientific progress has also been made in several other areas that may lead in the future to novel therapeutic approaches that can help fight CF in all individuals living with this disease. Thus, focusing on fundamental research in the CF field has and will continue to be of great importance. This has been one of the aims of the European Cystic Fibrosis Society (ECFS), which has promoted the ECFS Basic Science Conference (BSC) every year since 2004. This special issue covers the topics featured and discussed at the 17th ECFS BSC, held in Albufeira (Portugal) in March 2022, and highlights advances in understanding CFTR, in using personalized medicine, and in developing innovative strategies to identify breakthrough therapies. This introduction highlights the topics presented throughout this special issue, thereby underscoring the relevance of fundamental research in CF.
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