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Oren YS, Avizur-Barchad O, Ozeri-Galai E, Elgrabli R, Schirelman MR, Blinder T, Stampfer CD, Ordan M, Laselva O, Cohen-Cymberknoh M, Kerem E, Bear CE, Kerem B. Antisense oligonucleotide splicing modulation as a novel Cystic Fibrosis therapeutic approach for the W1282X nonsense mutation. J Cyst Fibros 2021; 21:630-636. [PMID: 34972649 DOI: 10.1016/j.jcf.2021.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND Antisense oligonucleotide- based drugs for splicing modulation were recently approved for various genetic diseases with unmet need. Here we aimed to generate skipping over exon 23 of the CFTR transcript, to eliminate the W1282X nonsense mutation and avoid RNA degradation induced by the nonsense mediated mRNA decay mechanism, allowing production of partially active CFTR proteins lacking exon 23. METHODS ∼80 ASOs were screened in 16HBEge W1282X cells. ASO candidates showing significant exon skipping were assessed for their W1282X allele selectivity and the increase of CFTR protein maturation and function. The effect of a highly potent ASO candidates was further analyzed in well differentiated primary human nasal epithelial cells, derived from a W1282X homozygous patient. RESULTS ASO screening led to identification of several ASOs that significantly decrease the level of CFTR transcripts including exon 23. These ASOs resulted in significant levels of mature CFTR protein and together with modulators restore the channel function following free uptake into these cells. Importantly, a highly potent lead ASOs, efficiently delivered by free uptake, was able to increase the level of transcripts lacking exon 23 and restore the CFTR function in cells from a W1282X homozygote patient. CONCLUSION The highly efficient exon 23 skipping induced by free uptake of the lead ASO and the resulting levels of mature CFTR protein exhibiting channel function in the presence of modulators, demonstrate the ASO therapeutic potential benefit for CF patients carrying the W1282X mutation with the objective to advance the lead candidate SPL23-2 to proof-of-concept clinical study.
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Affiliation(s)
- Yifat S Oren
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel
| | | | | | - Renana Elgrabli
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel
| | | | - Tehilla Blinder
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel
| | | | - Merav Ordan
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel
| | - Onofrio Laselva
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy; Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Malena Cohen-Cymberknoh
- Pediatric Pulmonology Unit and CF Center, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Eitan Kerem
- CF Center, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Christine E Bear
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Batsheva Kerem
- SpliSense Biohouse Labs, Hadassah Ein Kerem, Jerusalem, Israel; Department of Genetics, The Hebrew University, Jerusalem, Israel.
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52
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Integrity and Stability of PTC Bearing CFTR mRNA and Relevance to Future Modulator Therapies in Cystic Fibrosis. Genes (Basel) 2021; 12:genes12111810. [PMID: 34828417 PMCID: PMC8621375 DOI: 10.3390/genes12111810] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/16/2021] [Accepted: 11/18/2021] [Indexed: 12/26/2022] Open
Abstract
Major advances have recently been made in the development and application of CFTR (cystic fibrosis transmembrane conductance regulator) mutation class-specific modulator therapies, but to date, there are no approved modulators for Class I mutations, i.e., those introducing a premature termination codon (PTC) into the CFTR mRNA. Such mutations induce nonsense-mediated decay (NMD), a cellular quality control mechanism that reduces the quantity of PTC bearing mRNAs, presumably to avoid translation of potentially deleterious truncated CFTR proteins. The NMD-mediated reduction of PTC-CFTR mRNA molecules reduces the efficacy of one of the most promising approaches to treatment of such mutations, namely, PTC readthrough therapy, using molecules that induce the incorporation of near-cognate amino acids at the PTC codon, thereby enabling translation of a full-length protein. In this study, we measure the effect of three different PTC mutations on the abundance, integrity, and stability of respective CFTR mRNAs, using CFTR specific RT-qPCR-based assays. Altogether, our data suggest that optimized rescue of PTC mutations has to take into account (1) the different steady-state levels of the CFTR mRNA associated with each specific PTC mutation; (2) differences in abundance between the 3' and 5' regions of CFTR mRNA, even following PTC readthrough or NMD inhibition; and (3) variable effects on CFTR mRNA stability for each specific PTC mutation.
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53
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Laselva O, Guerra L, Castellani S, Favia M, Di Gioia S, Conese M. Small-molecule drugs for cystic fibrosis: Where are we now? Pulm Pharmacol Ther 2021; 72:102098. [PMID: 34793977 DOI: 10.1016/j.pupt.2021.102098] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/24/2021] [Accepted: 11/12/2021] [Indexed: 01/05/2023]
Abstract
The cystic fibrosis (CF) lung disease is due to the lack/dysfunction of the CF Transmembrane Conductance Regulator (CFTR), a chloride channel expressed by epithelial cells as the main regulator of ion and fluid homeostasis. More than 2000 genetic variation in the CFTR gene are known, among which those with identified pathomechanism have been divided into six VI mutation classes. A major advancement in the pharmacotherapy of CF has been the development of small-molecule drugs hitting the root of the disease, i.e. the altered ion and fluid transport through the airway epithelium. These drugs, called CFTR modulators, have been advanced to the clinics to treat nearly 90% of CF patients, including the CFTR potentiator ivacaftor, approved for residual function mutations (Classes III and IV), and combinations of correctors (lumacaftor, tezacaftor, elexacaftor) and ivacaftor for patients bearing at least one the F508del mutation, the most frequent mutation belonging to class II. To cover the 10% of CF patients without etiological therapies, other novel small-molecule CFTR modulators are in evaluation of their effectiveness in all the CFTR mutation classes: read-through agents for Class I, correctors, potentiators and amplifiers from different companies for Class II-V, stabilizers for Class VI. In alternative, other solute carriers, such as SLC26A9 and SLC6A14, are the focus of intensive investigation. Finally, other molecular targets are being evaluated for patients with no approved CFTR modulator therapy or as means of enhancing CFTR modulatory therapy, including small molecules forming ion channels, inhibitors of the ENaC sodium channel and potentiators of the calcium-activated chloride channel TMEM16A. This paper aims to give an up-to-date overview of old and novel CFTR modulators as well as of novel strategies based on small-molecule drugs. Further investigations in in-vivo and cell-based models as well as carrying out large prospective studies will be required to determine if novel CFTR modulators, stabilizers, amplifiers, and the ENaC inhibitors or TMEM16A potentiators will further improve the clinical outcomes in CF management.
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Affiliation(s)
- Onofrio Laselva
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Lorenzo Guerra
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Stefano Castellani
- Department of Medical Sciences and Human Oncology, University of Bari, Bari, Italy
| | - Maria Favia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Sante Di Gioia
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Massimo Conese
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy.
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A new platform for high-throughput therapy testing on iPSC-derived lung progenitor cells from cystic fibrosis patients. Stem Cell Reports 2021; 16:2825-2837. [PMID: 34678210 PMCID: PMC8581165 DOI: 10.1016/j.stemcr.2021.09.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/27/2021] [Accepted: 09/27/2021] [Indexed: 02/07/2023] Open
Abstract
For those people with cystic fibrosis carrying rare CFTR mutations not responding to currently available therapies, there is an unmet need for relevant tissue models for therapy development. Here, we describe a new testing platform that employs patient-specific induced pluripotent stem cells (iPSCs) differentiated to lung progenitor cells that can be studied using a dynamic, high-throughput fluorescence-based assay of CFTR channel activity. Our proof-of-concept studies support the potential use of this platform, together with a Canadian bioresource that contains iPSC lines and matched nasal cultures from people with rare mutations, to advance patient-oriented therapy development. Interventions identified in the high-throughput, stem cell-based model and validated in primary nasal cultures from the same person have the potential to be advanced as therapies. A Canadian resource (CFIT) has CF donor-matched iPSCs and nasal epithelial cells Lung progenitor cells (LPCs) differentiated from iPSCs express CFTR LPCs from people with rare CFTR mutations enable high-throughput therapy testing Matching nasal cultures can validate patient-specific drug responses in LPCs
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55
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Comprehensive Analysis of Combinatorial Pharmacological Treatments to Correct Nonsense Mutations in the CFTR Gene. Int J Mol Sci 2021; 22:ijms222111972. [PMID: 34769402 PMCID: PMC8584557 DOI: 10.3390/ijms222111972] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 12/11/2022] Open
Abstract
Cystic fibrosis (CF) is caused by loss of function of the CFTR chloride channel. A substantial number of CF patients carry nonsense mutations in the CFTR gene. These patients cannot directly benefit from pharmacological correctors and potentiators that have been developed for other types of CFTR mutations. We evaluated the efficacy of combinations of drugs targeting at various levels the effects of nonsense mutations: SMG1i to protect CFTR mRNA from nonsense-mediated decay (NMD), G418 and ELX-02 for readthrough, VX-809 and VX-445 to promote protein maturation and function, PTI-428 to enhance CFTR protein synthesis. We found that the extent of rescue and sensitivity to the various agents is largely dependent on the type of mutation, with W1282X and R553X being the mutations most and least sensitive to pharmacological treatments, respectively. In particular, W1282X-CFTR was highly responsive to NMD suppression by SMG1i but also required treatment with VX-445 corrector to show function. In contrast, G542X-CFTR required treatment with readthrough agents and VX-809. Importantly, we never found cooperativity between the NMD inhibitor and readthrough compounds. Our results indicate that treatment of CF patients with nonsense mutations requires a precision medicine approach with the design of specific drug combinations for each mutation.
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56
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Functional Restoration of CFTR Nonsense Mutations in Intestinal Organoids. J Cyst Fibros 2021; 21:246-253. [PMID: 34666947 DOI: 10.1016/j.jcf.2021.09.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND Pharmacotherapies for people with cystic fibrosis (pwCF) who have premature termination codons (PTCs) in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are under development. Thus far, clinical studies focused on compounds that induce translational readthrough (RT) at the mRNA PTC location. Recent studies using primary airway cells showed that PTC functional restoration can be achieved through combining compounds with multiple mode-of-actions. Here, we assessed induction of CFTR function in PTC-containing intestinal organoids using compounds targeting RT, nonsense mRNA mediated decay (NMD) and CFTR protein modulation. METHODS Rescue of PTC CFTR protein was assessed by forskolin-induced swelling of 12 intestinal organoid cultures carrying distinct PTC mutations. Effects of compounds on mRNA CFTR level was assessed by RT-qPCRs. RESULTS Whilst response varied between donors, significant rescue of CFTR function was achieved for most donors with the quintuple combination of a commercially available pharmacological equivalent of the RT compound (ELX-02-disulfate or ELX-02ds), NMD inhibitor SMG1i, correctors VX-445 and VX-661 and potentiator VX-770. The quintuple combination of pharmacotherapies reached swelling quantities higher than the mean swelling of three VX-809/VX-770-rescued F508del/F508del organoid cultures, indicating level of rescue is of clinical relevance as VX-770/VX-809-mediated F508del/F508del rescue in organoids correlate with substantial improvement of clinical outcome. CONCLUSIONS Whilst variation in efficacy was observed between genotypes as well as within genotypes, the data suggests that strong pharmacological rescue of PTC requires a combination of drugs that target RT, NMD and protein function.
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57
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Krishnamurthy S, Traore S, Cooney AL, Brommel CM, Kulhankova K, Sinn P, Newby G, Liu D, McCray P. Functional correction of CFTR mutations in human airway epithelial cells using adenine base editors. Nucleic Acids Res 2021; 49:10558-10572. [PMID: 34520545 PMCID: PMC8501978 DOI: 10.1093/nar/gkab788] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 08/26/2021] [Accepted: 09/01/2021] [Indexed: 12/31/2022] Open
Abstract
Mutations in the CFTR gene that lead to premature stop codons or splicing defects cause cystic fibrosis (CF) and are not amenable to treatment by small-molecule modulators. Here, we investigate the use of adenine base editor (ABE) ribonucleoproteins (RNPs) that convert A•T to G•C base pairs as a therapeutic strategy for three CF-causing mutations. Using ABE RNPs, we corrected in human airway epithelial cells premature stop codon mutations (R553X and W1282X) and a splice-site mutation (3849 + 10 kb C > T). Following ABE delivery, DNA sequencing revealed correction of these pathogenic mutations at efficiencies that reached 38-82% with minimal bystander edits or indels. This range of editing was sufficient to attain functional correction of CFTR-dependent anion channel activity in primary epithelial cells from CF patients and in a CF patient-derived cell line. These results demonstrate the utility of base editor RNPs to repair CFTR mutations that are not currently treatable with approved therapeutics.
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Affiliation(s)
| | - Soumba Traore
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
| | - Ashley L Cooney
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
| | - Christian M Brommel
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
- Molecular Medicine Graduate Program, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, USA
| | | | - Patrick L Sinn
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
- Molecular Medicine Graduate Program, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Paul B McCray
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
- Molecular Medicine Graduate Program, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, USA
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58
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Three-Dimensional Airway Spheroids and Organoids for Cystic Fibrosis Research. JOURNAL OF RESPIRATION 2021. [DOI: 10.3390/jor1040022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive multi-organ disease caused by mutations in the CF Transmembrane Conductance Regulator (CFTR) gene, with morbidity and mortality primacy related to the lung disease. The CFTR protein, a chloride/bicarbonate channel, is expressed at the apical side of airway epithelial cells and is mainly involved in appropriate ion and fluid transport across the epithelium. Although many animal and cellular models have been developed to study the pathophysiological consequences of the lack/dysfunction of CFTR, only the three-dimensional (3D) structures termed “spheroids” and “organoids” can enable the reconstruction of airway mucosa to model organ development, disease pathophysiology, and drug screening. Airway spheroids and organoids can be derived from different sources, including adult lungs and induced pluripotent stem cells (iPSCs), each with its advantages and limits. Here, we review the major features of airway spheroids and organoids, anticipating that their potential in the CF field has not been fully shown. Further work is mandatory to understand whether they can accomplish better outcomes than other culture conditions of airway epithelial cells for CF personalized therapies and tissue engineering aims.
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59
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Mutyam V, Sharma J, Li Y, Peng N, Chen J, Tang LP, Falk Libby E, Singh AK, Conrath K, Rowe SM. Novel Correctors and Potentiators Enhance Translational Readthrough in CFTR Nonsense Mutations. Am J Respir Cell Mol Biol 2021; 64:604-616. [PMID: 33616476 DOI: 10.1165/rcmb.2019-0291oc] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Premature-termination codons (PTCs) in CFTR (cystic fibrosis [CF] transmembrane conductance regulator) result in nonfunctional CFTR protein and are the proximate cause of ∼11% of CF-causing alleles, for which no treatments exist. The CFTR corrector lumacaftor and the potentiator ivacaftor improve CFTR function with terminal PTC mutations and enhance the effect of readthrough agents. Novel correctors GLPG2222 (corrector 1 [C1]), GLPG3221 (corrector 2 [C2]), and potentiator GLPG1837 compare favorably with lumacaftor and ivacaftor in vitro. Here, we evaluated the effect of correctors C1a and C2a (derivatives of C1 and C2) and GLPG1837 alone or in combination with the readthrough compound G418 on CFTR function using heterologous Fischer rat thyroid (FRT) cells, the genetically engineered human bronchial epithelial (HBE) 16HBE14o- cell lines, and primary human cells with PTC mutations. In FRT lines pretreated with G418, GLPG1837 elicited dose-dependent increases in CFTR activity that exceeded those from ivacaftor in FRT-W1282X and FRT-R1162X cells. A three-mechanism strategy consisting of G418, GLPG1837, and two correctors (C1a + C2a) yielded the greatest functional improvements in FRT and 16HBE14o- PTC variants, noting that correction and potentiation without readthrough was sufficient to stimulate CFTR activity for W1282X cells. GLPG1837 + C1a + C2a restored substantial function in G542X/F508del HBE cells and restored even more function for W1282X/F508del cells, largely because of the corrector/potentiator effect, with no additional benefit from G418. In G542X/R553X or R1162X/R1162X organoids, enhanced forskolin-induced swelling was observed with G418 + GLPG1837 + C1a + C2a, although GLPG1837 + C1a + C2a alone was sufficient to improve forskolin-induced swelling in W1282X/W1282X organoids. Combination of CFTR correctors, potentiators, and readthrough compounds augments the functional repair of CFTR nonsense mutations, indicating the potential for novel correctors and potentiators to restore function to truncated W1282X CFTR.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Steven M Rowe
- Department of Medicine.,Department of Pediatrics.,Department of Cell Developmental and Integrative Biology, and.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama
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60
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Pinto MC, Silva IAL, Figueira MF, Amaral MD, Lopes-Pacheco M. Pharmacological Modulation of Ion Channels for the Treatment of Cystic Fibrosis. J Exp Pharmacol 2021; 13:693-723. [PMID: 34326672 PMCID: PMC8316759 DOI: 10.2147/jep.s255377] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/30/2021] [Indexed: 12/12/2022] Open
Abstract
Cystic fibrosis (CF) is a life-shortening monogenic disease caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein, an anion channel that transports chloride and bicarbonate across epithelia. Despite clinical progress in delaying disease progression with symptomatic therapies, these individuals still develop various chronic complications in lungs and other organs, which significantly restricts their life expectancy and quality of life. The development of high-throughput assays to screen drug-like compound libraries have enabled the discovery of highly effective CFTR modulator therapies. These novel therapies target the primary defect underlying CF and are now approved for clinical use for individuals with specific CF genotypes. However, the clinically approved modulators only partially reverse CFTR dysfunction and there is still a considerable number of individuals with CF carrying rare CFTR mutations who remain without any effective CFTR modulator therapy. Accordingly, additional efforts have been pursued to identify novel and more potent CFTR modulators that may benefit a larger CF population. The use of ex vivo individual-derived specimens has also become a powerful tool to evaluate novel drugs and predict their effectiveness in a personalized medicine approach. In addition to CFTR modulators, pro-drugs aiming at modulating alternative ion channels/transporters are under development to compensate for the lack of CFTR function. These therapies may restore normal mucociliary clearance through a mutation-agnostic approach (ie, independent of CFTR mutation) and include inhibitors of the epithelial sodium channel (ENaC), modulators of the calcium-activated channel transmembrane 16A (TMEM16, or anoctamin 1) or of the solute carrier family 26A member 9 (SLC26A9), and anionophores. The present review focuses on recent progress and challenges for the development of ion channel/transporter-modulating drugs for the treatment of CF.
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Affiliation(s)
- Madalena C Pinto
- Biosystems & Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisboa, Lisboa, Portugal
| | - Iris A L Silva
- Biosystems & Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisboa, Lisboa, Portugal
| | - Miriam F Figueira
- Marsico Lung Institute/Cystic Fibrosis Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Margarida D Amaral
- Biosystems & Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisboa, Lisboa, Portugal
| | - Miquéias Lopes-Pacheco
- Biosystems & Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisboa, Lisboa, Portugal
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61
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Sharma J, Du M, Wong E, Mutyam V, Li Y, Chen J, Wangen J, Thrasher K, Fu L, Peng N, Tang L, Liu K, Mathew B, Bostwick RJ, Augelli-Szafran CE, Bihler H, Liang F, Mahiou J, Saltz J, Rab A, Hong J, Sorscher EJ, Mendenhall EM, Coppola CJ, Keeling KM, Green R, Mense M, Suto MJ, Rowe SM, Bedwell DM. A small molecule that induces translational readthrough of CFTR nonsense mutations by eRF1 depletion. Nat Commun 2021; 12:4358. [PMID: 34272367 PMCID: PMC8285393 DOI: 10.1038/s41467-021-24575-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/22/2021] [Indexed: 11/09/2022] Open
Abstract
Premature termination codons (PTCs) prevent translation of a full-length protein and trigger nonsense-mediated mRNA decay (NMD). Nonsense suppression (also termed readthrough) therapy restores protein function by selectively suppressing translation termination at PTCs. Poor efficacy of current readthrough agents prompted us to search for better compounds. An NMD-sensitive NanoLuc readthrough reporter was used to screen 771,345 compounds. Among the 180 compounds identified with readthrough activity, SRI-37240 and its more potent derivative SRI-41315, induce a prolonged pause at stop codons and suppress PTCs associated with cystic fibrosis in immortalized and primary human bronchial epithelial cells, restoring CFTR expression and function. SRI-41315 suppresses PTCs by reducing the abundance of the termination factor eRF1. SRI-41315 also potentiates aminoglycoside-mediated readthrough, leading to synergistic increases in CFTR activity. Combining readthrough agents that target distinct components of the translation machinery is a promising treatment strategy for diseases caused by PTCs. Premature termination codons can cause early translation termination and lead to disease. Here the authors perform a screen to identify compounds with readthrough activity and show that these reduce eRF1 levels to suppress premature termination associated with cystic fibrosis.
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Affiliation(s)
- Jyoti Sharma
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Microbiology, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Ming Du
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Eric Wong
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Venkateshwar Mutyam
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Yao Li
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Jianguo Chen
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Jamie Wangen
- Department of Molecular Biology and Genetics and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kari Thrasher
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Lianwu Fu
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Ning Peng
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Liping Tang
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Kaimao Liu
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | | | | | | | - Hermann Bihler
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Feng Liang
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Jerome Mahiou
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Josef Saltz
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Andras Rab
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Jeong Hong
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Eric J Sorscher
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Eric M Mendenhall
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL, USA
| | - Candice J Coppola
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL, USA
| | - Kim M Keeling
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Rachel Green
- Department of Molecular Biology and Genetics and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Martin Mense
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | | | - Steven M Rowe
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Pediatrics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - David M Bedwell
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA. .,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.
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Santos L, Mention K, Cavusoglu-Doran K, Sanz DJ, Bacalhau M, Lopes-Pacheco M, Harrison PT, Farinha CM. Comparison of Cas9 and Cas12a CRISPR editing methods to correct the W1282X-CFTR mutation. J Cyst Fibros 2021; 21:181-187. [PMID: 34103250 DOI: 10.1016/j.jcf.2021.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/07/2021] [Accepted: 05/22/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND W1282X-CFTR variant (c.3846G>A) is the second most common nonsense cystic fibrosis (CF)-causing mutation in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. Even though remarkable breakthroughs have been done towards CF treatment with the approval of four CFTR protein modulators, none of these are approved for patients with nonsense mutations. CRISPR gene editing tools can be of great value to permanently correct the genetic defects caused by these mutations. METHODS We compared the capacity of homology-directed repair (HDR) mediated by Cas9 or Cas12a to correct W1282X CFTR mutation in the CFF-16HBEge W1282X CFTR cell line (obtained from CFF), using Cas9/gRNA and Cas12a/gRNA ribonucleoproteins (RNPs) and single strand DNA (ssODN) oligonucleotide donors. RESULTS Cas9 shows higher levels of correction than Cas12a as, by electroporating cells with Cas9 RNPs and ssODN donor, nearly 18% of precise editing was achieved compared to just 8% for Cas12a. Such levels of correction increase the abundance of CFTR mRNA and protein, and partially restore CFTR function in the pool of edited cells to 18% of WT CFTR function. Moreover, homozygous corrected clones produced levels of mRNA, protein, and function comparable to those of cells expressing WT CFTR. CONCLUSION Altogether, this work demonstrates the potential of gene editing as a therapeutic strategy for CF directly correcting the root cause of the disease.
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Affiliation(s)
- Lúcia Santos
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal; Department of Physiology, University College Cork, Cork T12 K8AF, Ireland
| | - Karen Mention
- Department of Physiology, University College Cork, Cork T12 K8AF, Ireland
| | | | - David J Sanz
- Department of Physiology, University College Cork, Cork T12 K8AF, Ireland
| | - Mafalda Bacalhau
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal
| | - Miquéias Lopes-Pacheco
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal
| | - Patrick T Harrison
- Department of Physiology, University College Cork, Cork T12 K8AF, Ireland
| | - Carlos M Farinha
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal.
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Laselva O, Bartlett C, Gunawardena TNA, Ouyang H, Eckford PDW, Moraes TJ, Bear CE, Gonska T. Rescue of multiple class II CFTR mutations by elexacaftor+tezacaftor+ivacaftor mediated in part by the dual activities of elexacaftor as both corrector and potentiator. Eur Respir J 2021; 57:2002774. [PMID: 33303536 PMCID: PMC8209484 DOI: 10.1183/13993003.02774-2020] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 11/20/2020] [Indexed: 12/20/2022]
Abstract
Positive results in pre-clinical studies of the triple combination of elexacaftor, tezacaftor and ivacaftor, performed in airway epithelial cell cultures obtained from patients harbouring the class II cystic fibrosis transmembrane conductance regulator (CFTR) mutation F508del-CFTR, translated to impressive clinical outcomes for subjects carrying this mutation in clinical trials and approval of Trikafta.Encouraged by this correlation, we were prompted to evaluate the effect of the elexacaftor, tezacaftor and ivacaftor triple combination on primary nasal epithelial cultures obtained from individuals with rare class II CF-causing mutations (G85E, M1101K and N1303K) for which Trikafta is not approved.Cultures from individuals homozygous for M1101K responded better than cultures harbouring G85E and N1303K after treatment with the triple combination with respect to improvement in regulated channel function and protein processing. A similar genotype-specific effect of the triple combination was observed when the different mutations were expressed in HEK293 cells, supporting the hypothesis that these modulators may act directly on the mutant proteins. Detailed studies in nasal cultures and HEK293 cells showed that the corrector, elexacaftor, exhibited dual activity as both corrector and potentiator, and suggested that the potentiator activity contributes to its pharmacological activity.These pre-clinical studies using nasal epithelial cultures identified mutation genotypes for which elexacaftor, tezacaftor and ivacaftor may produce clinical responses that are comparable to, or inferior to, those observed for F508del-CFTR.
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Affiliation(s)
- Onofrio Laselva
- Programme in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Dept of Physiology, University of Toronto, Toronto, ON, Canada
| | - Claire Bartlett
- Programme in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Tarini N A Gunawardena
- Programme in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Programme in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Hong Ouyang
- Programme in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Paul D W Eckford
- Programme in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Theo J Moraes
- Programme in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Dept of Paediatrics, University of Toronto, Toronto, ON, Canada
| | - Christine E Bear
- Programme in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Dept of Physiology, University of Toronto, Toronto, ON, Canada
- Dept of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Tanja Gonska
- Programme in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Dept of Paediatrics, University of Toronto, Toronto, ON, Canada
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64
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Ensinck M, Mottais A, Detry C, Leal T, Carlon MS. On the Corner of Models and Cure: Gene Editing in Cystic Fibrosis. Front Pharmacol 2021; 12:662110. [PMID: 33986686 PMCID: PMC8111007 DOI: 10.3389/fphar.2021.662110] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/15/2021] [Indexed: 12/11/2022] Open
Abstract
Cystic fibrosis (CF) is a severe genetic disease for which curative treatment is still lacking. Next generation biotechnologies and more efficient cell-based and in vivo disease models are accelerating the development of novel therapies for CF. Gene editing tools, like CRISPR-based systems, can be used to make targeted modifications in the genome, allowing to correct mutations directly in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. Alternatively, with these tools more relevant disease models can be generated, which in turn will be invaluable to evaluate novel gene editing-based therapies for CF. This critical review offers a comprehensive description of currently available tools for genome editing, and the cell and animal models which are available to evaluate them. Next, we will give an extensive overview of proof-of-concept applications of gene editing in the field of CF. Finally, we will touch upon the challenges that need to be addressed before these proof-of-concept studies can be translated towards a therapy for people with CF.
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Affiliation(s)
- Marjolein Ensinck
- Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Angélique Mottais
- Institut de Recherche Expérimentale et Clinique, Louvain Centre for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
| | - Claire Detry
- Institut de Recherche Expérimentale et Clinique, Louvain Centre for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
| | - Teresinha Leal
- Institut de Recherche Expérimentale et Clinique, Louvain Centre for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
| | - Marianne S. Carlon
- Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
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Lopes-Pacheco M, Pedemonte N, Veit G. Discovery of CFTR modulators for the treatment of cystic fibrosis. Expert Opin Drug Discov 2021; 16:897-913. [PMID: 33823716 DOI: 10.1080/17460441.2021.1912732] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Cystic fibrosis (CF) is a life-threatening inherited disease caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein, an anion channel expressed at the apical membrane of secretory epithelia. CF leads to multiorgan dysfunction with progressive deterioration of lung function being the major cause of untimely death. Conventional CF therapies target only symptoms and consequences downstream of the primary genetic defect and the current life expectancy and quality of life of these individuals are still very limited. AREA COVERED CFTR modulator drugs are novel-specialized therapies that enhance or even restore functional expression of CFTR mutants and have been approved for clinical use for individuals with specific CF genotypes. This review summarizes classical approaches used for the pre-clinical development of CFTR correctors and potentiators as well as emerging strategies aiming to accelerate modulator development and expand theratyping efforts. EXPERT OPINION Highly effective CFTR modulator drugs are expected to deeply modify the disease course for the majority of individuals with CF. A multitude of experimental approaches have been established to accelerate the development of novel modulators. CF patient-derived specimens are valuable cell models to predict therapeutic effectiveness of existing (and novel) modulators in a precision medicine approach.
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Affiliation(s)
| | | | - Guido Veit
- Department of Physiology, McGill University, Montréal, Canada
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66
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Son JH, Phuan PW, Zhu JS, Lipman E, Cheung A, Tsui KY, Tantillo DJ, Verkman AS, Haggie PM, Kurth MJ. 1-BENZYLSPIRO[PIPERIDINE-4,1'-PYRIDO[3,4-b]indole] 'co-potentiators' for minimal function CFTR mutants. Eur J Med Chem 2021; 209:112888. [PMID: 33092904 PMCID: PMC7744356 DOI: 10.1016/j.ejmech.2020.112888] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/19/2020] [Accepted: 09/23/2020] [Indexed: 11/25/2022]
Abstract
We previously identified a spiro [piperidine-4,1-pyrido [3,4-b]indole] class of co-potentiators that function in synergy with existing CFTR potentiators such as VX-770 or GLGP1837 to restore channel activity of a defined subset of minimal function cystic fibrosis transmembrane conductance regulator (CFTR) mutants. Here, structure-activity studies were conducted to improve their potency over the previously identified compound, 20 (originally termed CP-A01). Targeted synthesis of 37 spiro [piperidine-4,1-pyrido [3,4-b]indoles] was generally accomplished using versatile two or three step reaction protocols with each step having high efficiency. Structure-activity relationship studies established that analog 2i, with 6'-methoxyindole and 2,4,5-trifluorobenzyl substituents, had the greatest potency for activation of N1303K-CFTR, with EC50 ∼600 nM representing an ∼17-fold improvement over the original compound identified in a small molecule screen.
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Affiliation(s)
- Jung-Ho Son
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Puay-Wah Phuan
- Departments of Medicine & Physiology, University of California San Francisco, CA 94143, USA
| | - Jie S Zhu
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Elena Lipman
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Amy Cheung
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Ka Yi Tsui
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Dean J Tantillo
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Alan S Verkman
- Departments of Medicine & Physiology, University of California San Francisco, CA 94143, USA
| | - Peter M Haggie
- Departments of Medicine & Physiology, University of California San Francisco, CA 94143, USA.
| | - Mark J Kurth
- Department of Chemistry, University of California, Davis, CA, 95616, USA.
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McHugh DR, Cotton CU, Hodges CA. Synergy between Readthrough and Nonsense Mediated Decay Inhibition in a Murine Model of Cystic Fibrosis Nonsense Mutations. Int J Mol Sci 2020; 22:ijms22010344. [PMID: 33396210 PMCID: PMC7794695 DOI: 10.3390/ijms22010344] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/17/2020] [Accepted: 12/29/2020] [Indexed: 12/15/2022] Open
Abstract
Many heritable genetic disorders arise from nonsense mutations, which generate premature termination codons (PTCs) in transcribed mRNA. PTCs ablate protein synthesis by prematurely terminating the translation of mutant mRNA, as well as reducing mutant mRNA quantity through targeted degradation by nonsense-mediated decay (NMD) mechanisms. Therapeutic strategies for nonsense mutations include facilitating ribosomal readthrough of the PTC and/or inhibiting NMD to restore protein function. However, the efficacy of combining readthrough agents and NMD inhibitors has not been thoroughly explored. In this study, we examined combinations of known NMD inhibitors and readthrough agents using functional analysis of the CFTR protein in primary cells from a mouse model carrying a G542X nonsense mutation in Cftr. We observed synergy between an inhibitor of the NMD component SMG-1 (SMG1i) and the readthrough agents G418, gentamicin, and paromomycin, but did not observe synergy with readthrough caused by amikacin, tobramycin, PTC124, escin, or amlexanox. These results indicate that treatment with NMD inhibitors can increase the quantity of functional protein following readthrough, and that combining NMD inhibitors and readthrough agents represents a potential therapeutic option for treating nonsense mutations.
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Affiliation(s)
- Daniel R. McHugh
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA;
| | - Calvin U. Cotton
- Department of Pediatrics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA;
- Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
| | - Craig A. Hodges
- Department of Genetics and Genome Sciences, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA;
- Department of Pediatrics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA;
- Correspondence:
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Laselva O, McCormack J, Bartlett C, Ip W, Gunawardena TNA, Ouyang H, Eckford PDW, Gonska T, Moraes TJ, Bear CE. Preclinical Studies of a Rare CF-Causing Mutation in the Second Nucleotide Binding Domain (c.3700A>G) Show Robust Functional Rescue in Primary Nasal Cultures by Novel CFTR Modulators. J Pers Med 2020; 10:jpm10040209. [PMID: 33167369 PMCID: PMC7712331 DOI: 10.3390/jpm10040209] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022] Open
Abstract
The combination therapies ORKAMBITM and TRIKAFTATM are approved for people who have the F508del mutation on at least one allele. In this study we examine the effects of potentiator and corrector combinations on the rare mutation c.3700A>G. This mutation produces a cryptic splice site that deletes six amino acids in NBD2 (I1234-R1239del). Like F508del it causes protein misprocessing and reduced chloride channel function. We show that a novel cystic fibrosis transmembrane conductance regulator CFTR modulator triple combination (AC1, corrector, AC2-2, co-potentiator and AP2, potentiator), rescued I1234-R1239del-CFTR activity to WT-CFTR level in HEK293 cells. Moreover, we show that although the response to ORKAMBI was modest in nasal epithelial cells from two individuals homozygous for I1234-R1239del-CFTR, a substantial functional rescue was achieved with the novel triple combination. Interestingly, while both the novel CFTR triple combination and TRIKAFTATM treatment showed functional rescue in gene-edited I1234-R1239del-CFTR-expressing HBE cells and in nasal cells from two CF patients heterozygous for I1234-R1239del/W1282X, nasal cells homozygous for I1234-R1239del-CFTR showed no significant response to the TRIKAFTATM combination. These data suggest a potential benefit of CFTR modulators on the functional rescue of I1234-R1239del -CFTR, which arises from the rare CF-causing mutation c.3700A>G, and highlight that patient tissues are crucial to our full understanding of functional rescue in rare CFTR mutations.
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Affiliation(s)
- Onofrio Laselva
- Programme in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (O.L.); (J.M.); (T.N.A.G.); (P.D.W.E.)
- Department of Physiology, University of Toronto, Toronto, ON M5G 8X4, Canada
| | - Jacqueline McCormack
- Programme in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (O.L.); (J.M.); (T.N.A.G.); (P.D.W.E.)
| | - Claire Bartlett
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (C.B.); (W.I.); (H.O.); (T.G.); (T.J.M.)
| | - Wan Ip
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (C.B.); (W.I.); (H.O.); (T.G.); (T.J.M.)
| | - Tarini N. A. Gunawardena
- Programme in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (O.L.); (J.M.); (T.N.A.G.); (P.D.W.E.)
| | - Hong Ouyang
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (C.B.); (W.I.); (H.O.); (T.G.); (T.J.M.)
| | - Paul D. W. Eckford
- Programme in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (O.L.); (J.M.); (T.N.A.G.); (P.D.W.E.)
| | - Tanja Gonska
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (C.B.); (W.I.); (H.O.); (T.G.); (T.J.M.)
- Department of Paediatrics, University of Toronto, Toronto, ON M5G 8X4, Canada
| | - Theo J. Moraes
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (C.B.); (W.I.); (H.O.); (T.G.); (T.J.M.)
- Department of Paediatrics, University of Toronto, Toronto, ON M5G 8X4, Canada
| | - Christine E. Bear
- Programme in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada; (O.L.); (J.M.); (T.N.A.G.); (P.D.W.E.)
- Department of Physiology, University of Toronto, Toronto, ON M5G 8X4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5G 8X4, Canada
- Correspondence: ; Tel.: +1-416-816-5981
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Joynt AT, Evans TA, Pellicore MJ, Davis-Marcisak EF, Aksit MA, Eastman AC, Patel SU, Paul KC, Osorio DL, Bowling AD, Cotton CU, Raraigh KS, West NE, Merlo CA, Cutting GR, Sharma N. Evaluation of both exonic and intronic variants for effects on RNA splicing allows for accurate assessment of the effectiveness of precision therapies. PLoS Genet 2020; 16:e1009100. [PMID: 33085659 PMCID: PMC7605713 DOI: 10.1371/journal.pgen.1009100] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/02/2020] [Accepted: 09/08/2020] [Indexed: 12/21/2022] Open
Abstract
Elucidating the functional consequence of molecular defects underlying genetic diseases enables appropriate design of therapeutic options. Treatment of cystic fibrosis (CF) is an exemplar of this paradigm as the development of CFTR modulator therapies has allowed for targeted and effective treatment of individuals harboring specific genetic variants. However, the mechanism of these drugs limits effectiveness to particular classes of variants that allow production of CFTR protein. Thus, assessment of the molecular mechanism of individual variants is imperative for proper assignment of these precision therapies. This is particularly important when considering variants that affect pre-mRNA splicing, thus limiting success of the existing protein-targeted therapies. Variants affecting splicing can occur throughout exons and introns and the complexity of the process of splicing lends itself to a variety of outcomes, both at the RNA and protein levels, further complicating assessment of disease liability and modulator response. To investigate the scope of this challenge, we evaluated splicing and downstream effects of 52 naturally occurring CFTR variants (exonic = 15, intronic = 37). Expression of constructs containing select CFTR intronic sequences and complete CFTR exonic sequences in cell line models allowed for assessment of RNA and protein-level effects on an allele by allele basis. Characterization of primary nasal epithelial cells obtained from individuals harboring splice variants corroborated in vitro data. Notably, we identified exonic variants that result in complete missplicing and thus a lack of modulator response (e.g. c.2908G>A, c.523A>G), as well as intronic variants that respond to modulators due to the presence of residual normally spliced transcript (e.g. c.4242+2T>C, c.3717+40A>G). Overall, our data reveals diverse molecular outcomes amongst both exonic and intronic variants emphasizing the need to delineate RNA, protein, and functional effects of each variant in order to accurately assign precision therapies. Genetic variants that impact pre-mRNA splicing are a common cause of genetic disease and have varying downstream molecular consequences. As a result, precision therapies that function at the protein level are not always effective for these variants and thus careful assessment is necessary. Here we evaluate RNA-level effects of 52 variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and show that study of splicing and its consequences allows for more accurate assignment of precision therapies.
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Affiliation(s)
- Anya T. Joynt
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Taylor A. Evans
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Matthew J. Pellicore
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Emily F. Davis-Marcisak
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Melis A. Aksit
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alice C. Eastman
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shivani U. Patel
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Kathleen C. Paul
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Derek L. Osorio
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alyssa D. Bowling
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Calvin U. Cotton
- Departments of Pediatrics, Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Karen S. Raraigh
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Natalie E. West
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Christian A. Merlo
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Garry R. Cutting
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (GRC); (NS)
| | - Neeraj Sharma
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (GRC); (NS)
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King NE, Suzuki S, Barillà C, Hawkins FJ, Randell SH, Reynolds SD, Stripp BR, Davis BR. Correction of Airway Stem Cells: Genome Editing Approaches for the Treatment of Cystic Fibrosis. Hum Gene Ther 2020; 31:956-972. [PMID: 32741223 PMCID: PMC7495916 DOI: 10.1089/hum.2020.160] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/30/2020] [Indexed: 12/26/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive disease caused by variations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Although CF affects multiple organs, the primary cause of mortality is respiratory failure resulting from poor clearance of hyperviscous secretions and subsequent airway infection. Recently developed CFTR modulators provide significant therapeutic benefit to the majority of CF individuals. However, treatments directed at the underlying cause are needed for the ∼7% of CF patients who are not expected to be responsive to these modulators. Genome editing can restore the native CFTR genetic sequence and function to mutant cells, representing an approach to establish durable physiologic CFTR correction. Although editing the CFTR gene in various airway cell types may transiently restore CFTR activity, effort is focused on editing airway basal stem/progenitor cells, since their correction would allow appropriate and durable expression of CFTR in stem cell-derived epithelial cell types. Substantial progress has been made to directly correct airway basal cells in vitro, theoretically enabling transplantation of autologous corrected cells to regenerate an airway with CFTR functional cells. Another approach to create autologous, gene-edited airway basal cells is derivation of CF donor-specific induced pluripotent stem cells, correction of the CFTR gene, and subsequent directed differentiation to airway basal cells. Further work is needed to translate these advances by developing effective transplantation methods. Alternatively, gene editing in vivo may enable CFTR correction. However, this approach will require robust delivery methods ensuring that basal cells are efficiently targeted and corrected. Recent advances in gene editing-based therapies provide hope that the genetic underpinning of CF can be durably corrected in airway epithelial stem cells, thereby preventing or treating lung disease in all people with CF.
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Affiliation(s)
- Nicholas E. King
- Center for Stem Cell and Regenerative Medicine, Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Shingo Suzuki
- Center for Stem Cell and Regenerative Medicine, Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Cristina Barillà
- Center for Stem Cell and Regenerative Medicine, Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Finn J. Hawkins
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
| | - Scott H. Randell
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Susan D. Reynolds
- Center for Perinatal Research, Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Barry R. Stripp
- Lung and Regenerative Medicine Institutes, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Brian R. Davis
- Center for Stem Cell and Regenerative Medicine, Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
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71
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Laselva O, Bartlett C, Popa A, Ouyang H, Gunawardena TNA, Gonska T, Moraes TJ, Bear CE. Emerging preclinical modulators developed for F508del-CFTR have the potential to be effective for ORKAMBI resistant processing mutants. J Cyst Fibros 2020; 20:106-119. [PMID: 32741662 DOI: 10.1016/j.jcf.2020.07.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/07/2020] [Accepted: 07/22/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND F508del is prototypical of Class 2 CFTR mutations associated with protein misprocessing and reduced function. Corrector compounds like lumacaftor partially rescue the processing defect of F508del-CFTR whereas potentiators like ivacaftor, enhance its channel activity once trafficked to the cell surface. We asked if emerging modulators developed for F508del-CFTR can rescue Class 2 mutations previously shown to be poorly responsive to lumacaftor and ivacaftor. METHODS Rescue of mutant CFTRs by the correctors: AC1, AC2-1 or AC2-2 and the potentiator, AP2, was studied in HEK-293 cells and in primary human nasal epithelial (HNE) cultures, using a membrane potential assay and Ussing chamber, respectively. RESULTS In HEK-293 cells, we found that a particular combination of corrector molecules (AC1 plus AC2-1) and a potentiator (AP2) was effective in rescuing both the misprocessing and reduced function of M1101K and G85E respectively. These findings were recapitulated in patient-derived nasal cultures, although another corrector combination, AC1 plus AC2-2 also improved misprocessing in these primary tissues. Interestingly, while this corrector combination only led to a modest increase in the abundance of mature N1303K-CFTR it did enable its functional expression in the presence of the potentiator, AP2, in part, because the nominal corrector, AC2-2 also exhibits potentiator activity. CONCLUSIONS Strategic combinations of novel modulators can potentially rescue Class 2 mutants thought to be relatively unresponsive to lumacaftor and ivacaftor.
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Affiliation(s)
- Onofrio Laselva
- Programme in Molecular Medicine, Hospital for Sick Children, Toronto, Canada; Department of Physiology, University of Toronto, Toronto, Canada
| | - Claire Bartlett
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, Canada
| | - Alec Popa
- Programme in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - Hong Ouyang
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, Canada
| | | | - Tanja Gonska
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, Canada; Department of Paediatrics, University of Toronto, Toronto, Canada
| | - Theo J Moraes
- Programme in Translational Medicine, Hospital for Sick Children, Toronto, Canada; Department of Paediatrics, University of Toronto, Toronto, Canada
| | - Christine E Bear
- Programme in Molecular Medicine, Hospital for Sick Children, Toronto, Canada; Department of Physiology, University of Toronto, Toronto, Canada; Department of Biochemistry, University of Toronto, Toronto, Canada.
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72
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Erwood S, Laselva O, Bily TM, Brewer RA, Rutherford AH, Bear CE, Ivakine EA. Allele-Specific Prevention of Nonsense-Mediated Decay in Cystic Fibrosis Using Homology-Independent Genome Editing. Mol Ther Methods Clin Dev 2020; 17:1118-1128. [PMID: 32490033 PMCID: PMC7256445 DOI: 10.1016/j.omtm.2020.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/07/2020] [Indexed: 02/07/2023]
Abstract
Nonsense-mediated decay (NMD) is a major pathogenic mechanism underlying a diversity of genetic disorders. Nonsense variants tend to lead to more severe disease phenotypes and are often difficult targets for small molecule therapeutic development as a result of insufficient protein production. The treatment of cystic fibrosis (CF), an autosomal recessive disease caused by mutations in the CFTR gene, exemplifies the challenge of therapeutically addressing nonsense mutations in human disease. Therapeutic development in CF has led to multiple, highly successful protein modulatory interventions, yet no targeted therapies have been approved for nonsense mutations. Here, we have designed a CRISPR-Cas9-based strategy for the targeted prevention of NMD of CFTR transcripts containing the second most common nonsense variant listed in CFTR2, W1282X. By introducing a deletion of the downstream genic region following the premature stop codon, we demonstrate significantly increased protein expression of this mutant variant. Notably, in combination with protein modulators, genome editing significantly increases the potentiated channel activity of W1282X-CFTR in human bronchial epithelial cells. Furthermore, we show how the outlined approach can be modified to permit allele-specific editing. The described approach can be extended to other late-occurring nonsense mutations in the CFTR gene or applied as a generalized approach for gene-specific prevention of NMD in disorders where a truncated protein product retains full or partial functionality.
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Affiliation(s)
- Steven Erwood
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Onofrio Laselva
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Teija M.I. Bily
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, ON, Canada
| | - Reid A. Brewer
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, ON, Canada
| | - Alexandra H. Rutherford
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, ON, Canada
| | - Christine E. Bear
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Evgueni A. Ivakine
- Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
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73
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Cuevas-Ocaña S, Laselva O, Avolio J, Nenna R. The era of CFTR modulators: improvements made and remaining challenges. Breathe (Sheff) 2020; 16:200016. [PMID: 33304402 PMCID: PMC7714553 DOI: 10.1183/20734735.0016-2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The entry into the clinic of CFTR modulators such as TRIKAFTA has significantly improved life for ∼90% CF patients carrying one or two F508del mutations but challenges remain for rare CFTR mutations and the management of lung infections @SaraOcana1 https://bit.ly/3aRafQF.
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Affiliation(s)
- Sara Cuevas-Ocaña
- Wolfson Centre for Stem Cells, Tissue Engineering and Modelling, School of Medicine, University of Nottingham Biodiscovery Institute, Nottingham, UK
| | - Onofrio Laselva
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Canada
- Dept of Physiology, University of Toronto, Toronto, Canada
| | - Julie Avolio
- Program in Translational Medicine, SickKids Research Institute, The Hospital for Sick Children, Toronto, Canada
| | - Raffaella Nenna
- Dept of Paediatrics, “Sapienza” University of Rome, Rome, Italy
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74
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Maule G, Arosio D, Cereseto A. Gene Therapy for Cystic Fibrosis: Progress and Challenges of Genome Editing. Int J Mol Sci 2020; 21:E3903. [PMID: 32486152 PMCID: PMC7313467 DOI: 10.3390/ijms21113903] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/27/2020] [Accepted: 05/28/2020] [Indexed: 02/07/2023] Open
Abstract
Since the early days of its conceptualization and application, human gene transfer held the promise of a permanent solution to genetic diseases including cystic fibrosis (CF). This field went through alternated periods of enthusiasm and distrust. The development of refined technologies allowing site specific modification with programmable nucleases highly revived the gene therapy field. CRISPR nucleases and derived technologies tremendously facilitate genome manipulation offering diversified strategies to reverse mutations. Here we discuss the advancement of gene therapy, from therapeutic nucleic acids to genome editing techniques, designed to reverse genetic defects in CF. We provide a roadmap through technologies and strategies tailored to correct different types of mutations in the cystic fibrosis transmembrane regulator (CFTR) gene, and their applications for the development of experimental models valuable for the advancement of CF therapies.
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Affiliation(s)
- Giulia Maule
- Department of Cellular Computational Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy;
- National Council of Research, CNR, 38123 Trento, Italy;
| | | | - Anna Cereseto
- Department of Cellular Computational Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy;
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75
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Sharma J, Keeling KM, Rowe SM. Pharmacological approaches for targeting cystic fibrosis nonsense mutations. Eur J Med Chem 2020; 200:112436. [PMID: 32512483 DOI: 10.1016/j.ejmech.2020.112436] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 12/11/2022]
Abstract
Cystic fibrosis (CF) is a monogenic autosomal recessive disorder. The clinical manifestations of the disease are caused by ∼2,000 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. It is unlikely that any one approach will be efficient in correcting all defects. The recent approvals of ivacaftor, lumacaftor/ivacaftor and elexacaftor/tezacaftor/ivacaftor represent the genesis of a new era of precision combination medicine for the CF patient population. In this review, we discuss targeted translational readthrough approaches as mono and combination therapies for CFTR nonsense mutations. We examine the current status of efficacy of translational readthrough/nonsense suppression therapies and their limitations, including non-native amino acid incorporation at PTCs and nonsense-mediated mRNA decay (NMD), along with approaches to tackle these limitations. We further elaborate on combining various therapies such as readthrough agents, NMD inhibitors, and corrector/potentiators to improve the efficacy and safety of suppression therapy. These mutation specific strategies that are directed towards the basic CF defects should positively impact CF patients bearing nonsense mutations.
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Affiliation(s)
- Jyoti Sharma
- Department of Medicine, University of Alabama at Birmingham (UAB), USA; Department of Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), USA
| | - Kim M Keeling
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), USA; Department of Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), USA
| | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham (UAB), USA; Department of Pediatrics, University of Alabama at Birmingham (UAB), USA; Department of Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), USA.
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76
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Suzuki S, Crane AM, Anirudhan V, Barillà C, Matthias N, Randell SH, Rab A, Sorscher EJ, Kerschner JL, Yin S, Harris A, Mendel M, Kim K, Zhang L, Conway A, Davis BR. Highly Efficient Gene Editing of Cystic Fibrosis Patient-Derived Airway Basal Cells Results in Functional CFTR Correction. Mol Ther 2020; 28:1684-1695. [PMID: 32402246 DOI: 10.1016/j.ymthe.2020.04.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 04/01/2020] [Accepted: 04/23/2020] [Indexed: 12/26/2022] Open
Abstract
There is a strong rationale to consider future cell therapeutic approaches for cystic fibrosis (CF) in which autologous proximal airway basal stem cells, corrected for CFTR mutations, are transplanted into the patient's lungs. We assessed the possibility of editing the CFTR locus in these cells using zinc-finger nucleases and have pursued two approaches. The first, mutation-specific correction, is a footprint-free method replacing the CFTR mutation with corrected sequences. We have applied this approach for correction of ΔF508, demonstrating restoration of mature CFTR protein and function in air-liquid interface cultures established from bulk edited basal cells. The second is targeting integration of a partial CFTR cDNA within an intron of the endogenous CFTR gene, providing correction for all CFTR mutations downstream of the integration and exploiting the native CFTR promoter and chromatin architecture for physiologically relevant expression. Without selection, we observed highly efficient, site-specific targeted integration in basal cells carrying various CFTR mutations and demonstrated restored CFTR function at therapeutically relevant levels. Significantly, Omni-ATAC-seq analysis revealed minimal impact on the positions of open chromatin within the native CFTR locus. These results demonstrate efficient functional correction of CFTR and provide a platform for further ex vivo and in vivo editing.
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Affiliation(s)
- Shingo Suzuki
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ana M Crane
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Varada Anirudhan
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Cristina Barillà
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Nadine Matthias
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Scott H Randell
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Andras Rab
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Eric J Sorscher
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jenny L Kerschner
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Shiyi Yin
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ann Harris
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | | | - Kenneth Kim
- Sangamo Therapeutics, Richmond, CA 94804, USA
| | - Lei Zhang
- Sangamo Therapeutics, Richmond, CA 94804, USA
| | | | - Brian R Davis
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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77
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Jiang T, Henderson JM, Coote K, Cheng Y, Valley HC, Zhang XO, Wang Q, Rhym LH, Cao Y, Newby GA, Bihler H, Mense M, Weng Z, Anderson DG, McCaffrey AP, Liu DR, Xue W. Chemical modifications of adenine base editor mRNA and guide RNA expand its application scope. Nat Commun 2020; 11:1979. [PMID: 32332735 PMCID: PMC7181807 DOI: 10.1038/s41467-020-15892-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/02/2020] [Indexed: 12/13/2022] Open
Abstract
CRISPR-Cas9-associated base editing is a promising tool to correct pathogenic single nucleotide mutations in research or therapeutic settings. Efficient base editing requires cellular exposure to levels of base editors that can be difficult to attain in hard-to-transfect cells or in vivo. Here we engineer a chemically modified mRNA-encoded adenine base editor that mediates robust editing at various cellular genomic sites together with moderately modified guide RNA, and show its therapeutic potential in correcting pathogenic single nucleotide mutations in cell and animal models of diseases. The optimized chemical modifications of adenine base editor mRNA and guide RNA expand the applicability of CRISPR-associated gene editing tools in vitro and in vivo.
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Affiliation(s)
- Tingting Jiang
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | | | - Kevin Coote
- Cystic Fibrosis Foundation, CFFT Lab, Lexington, MA, 02421, USA
| | - Yi Cheng
- Cystic Fibrosis Foundation, CFFT Lab, Lexington, MA, 02421, USA
| | | | - Xiao-Ou Zhang
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Qin Wang
- School of Life Sciences and Technology, Tongji University, 200092, Shanghai, China
| | - Luke H Rhym
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yueying Cao
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Hermann Bihler
- Cystic Fibrosis Foundation, CFFT Lab, Lexington, MA, 02421, USA
| | - Martin Mense
- Cystic Fibrosis Foundation, CFFT Lab, Lexington, MA, 02421, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Daniel G Anderson
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Wen Xue
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA.
- Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA.
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78
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NandyMazumdar M, Yin S, Paranjapye A, Kerschner JL, Swahn H, Ge A, Leir SH, Harris A. Looping of upstream cis-regulatory elements is required for CFTR expression in human airway epithelial cells. Nucleic Acids Res 2020; 48:3513-3524. [PMID: 32095812 PMCID: PMC7144911 DOI: 10.1093/nar/gkaa089] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 01/14/2020] [Accepted: 02/03/2020] [Indexed: 12/14/2022] Open
Abstract
The CFTR gene lies within an invariant topologically associated domain (TAD) demarcated by CTCF and cohesin, but shows cell-type specific control mechanisms utilizing different cis-regulatory elements (CRE) within the TAD. Within the respiratory epithelium, more than one cell type expresses CFTR and the molecular mechanisms controlling its transcription are likely divergent between them. Here, we determine how two extragenic CREs that are prominent in epithelial cells in the lung, regulate expression of the gene. We showed earlier that these CREs, located at -44 and -35 kb upstream of the promoter, have strong cell-type-selective enhancer function. They are also responsive to inflammatory mediators and to oxidative stress, consistent with a key role in CF lung disease. Here, we use CRISPR/Cas9 technology to remove these CREs from the endogenous locus in human bronchial epithelial cells. Loss of either site extinguished CFTR expression and abolished long-range interactions between these sites and the gene promoter, suggesting non-redundant enhancers. The deletions also greatly reduced promoter interactions with the 5' TAD boundary. We show substantial recruitment of RNAPII to the -35 kb element and identify CEBPβ as a key activator of airway expression of CFTR, likely through occupancy at this CRE and the gene promoter.
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Affiliation(s)
- Monali NandyMazumdar
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Shiyi Yin
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Alekh Paranjapye
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Jenny L Kerschner
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Hannah Swahn
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Alex Ge
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Shih-Hsing Leir
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44116, USA
| | - Ann Harris
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44116, USA
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79
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Guerra L, Favia M, Di Gioia S, Laselva O, Bisogno A, Casavola V, Colombo C, Conese M. The preclinical discovery and development of the combination of ivacaftor + tezacaftor used to treat cystic fibrosis. Expert Opin Drug Discov 2020; 15:873-891. [PMID: 32290721 DOI: 10.1080/17460441.2020.1750592] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Cystic Fibrosis (CF) is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. The most common mutation, F508del, induces protein misprocessing and loss of CFTR function. The discovery through in vitro studies of the CFTR correctors (i.e. lumacaftor, tezacaftor) that partially rescue the misprocessing of F508del-CFTR with the potentiator ivacaftor is promising in giving an unprecedented clinical benefit in affected patients. AREAS COVERED Online databases were searched using key phrases for CF and CFTR modulators. Tezacaftor-ivacaftor treatment has proved to be safer than lumacaftor-ivacaftor, although clinical efficacy is similar. Further clinical efficacy has ensued with the introduction of triple therapy, i.e. applying second-generation correctors, such as VX-569 and VX-445 (elexacaftor) to tezacaftor-ivacaftor. The triple combinations will herald the availability of etiologic therapies for patients for whom no CFTR modulators are currently applied (i.e. F508del/minimal function mutations) and enhance CFTR modulator therapy for patients homozygous for F508del. EXPERT OPINION CF patient-derived tissue models are being explored to determine donor-specific response to current approved and future novel CFTR modulators for F508del and other rare mutations. The discovery and validation of biomarkers of CFTR modulation will complement these studies in the long term and in real-life world.
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Affiliation(s)
- Lorenzo Guerra
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari , Bari, Italy
| | - Maria Favia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari , Bari, Italy
| | - Sante Di Gioia
- Department of Medical and Surgical Sciences, University of Foggia , Foggia, Italy
| | - Onofrio Laselva
- Programme in Molecular Medicine, Research Institute, Hospital for Sick Children , Toronto, Ontario, Canada.,Department of Physiology, University of Toronto , Toronto, Ontario, Canada
| | - Arianna Bisogno
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Centro Regionale di Riferimento per la Fibrosi Cistica, Università degli Studi di Milano , Milan, Italy
| | - Valeria Casavola
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari , Bari, Italy
| | - Carla Colombo
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Centro Regionale di Riferimento per la Fibrosi Cistica, Università degli Studi di Milano , Milan, Italy
| | - Massimo Conese
- Department of Medical and Surgical Sciences, University of Foggia , Foggia, Italy
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80
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Keenan MM, Huang L, Jordan NJ, Wong E, Cheng Y, Valley HC, Mahiou J, Liang F, Bihler H, Mense M, Guo S, Monia BP. Nonsense-mediated RNA Decay Pathway Inhibition Restores Expression and Function of W1282X CFTR. Am J Respir Cell Mol Biol 2020; 61:290-300. [PMID: 30836009 DOI: 10.1165/rcmb.2018-0316oc] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The recessive genetic disease cystic fibrosis (CF) is caused by loss-of-function mutations in the CFTR (CF transmembrane conductance regulator) gene. Approximately 10% of patients with CF have at least one allele with a nonsense mutation in CFTR. Nonsense mutations generate premature termination codons that can subject mRNA transcripts to rapid degradation through the nonsense-mediated mRNA decay (NMD) pathway. Currently, there are no approved therapies that specifically target nonsense mutations in CFTR. Here, we identified antisense oligonucleotides (ASOs) that target the NMD factor SMG1 to inhibit the NMD pathway, and determined their effects on the W1282X CFTR mutation. First, we developed and validated two in vitro models of the W1282X CFTR mutation. Next, we treated these cells with antisense oligonucleotides to inhibit NMD and measured the effects of these treatments on W1282X expression and function. SMG1-ASO-mediated NMD inhibition upregulated the RNA, protein, and surface-localized protein expression of the truncated W1282X gene product. Additionally, these ASOs increased the CFTR chloride channel function in cells homozygous for the W1282X mutation. Our approach suggests a new therapeutic strategy for patients harboring nonsense mutations and may be beneficial as a single agent in patients with CF and the W1282X mutation.
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Affiliation(s)
| | - Lulu Huang
- Ionis Pharmaceuticals, Carlsbad, California; and
| | - Nikole J Jordan
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, Massachusetts
| | - Eric Wong
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, Massachusetts
| | - Yi Cheng
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, Massachusetts
| | - Hillary C Valley
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, Massachusetts
| | - Jerome Mahiou
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, Massachusetts
| | - Feng Liang
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, Massachusetts
| | - Hermann Bihler
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, Massachusetts
| | - Martin Mense
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, Massachusetts
| | - Shuling Guo
- Ionis Pharmaceuticals, Carlsbad, California; and
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81
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Laselva O, Stone TA, Bear CE, Deber CM. Anti-Infectives Restore ORKAMBI ® Rescue of F508del-CFTR Function in Human Bronchial Epithelial Cells Infected with Clinical Strains of P. aeruginosa. Biomolecules 2020; 10:biom10020334. [PMID: 32092967 PMCID: PMC7072183 DOI: 10.3390/biom10020334] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/04/2020] [Accepted: 02/16/2020] [Indexed: 12/21/2022] Open
Abstract
Chronic infection and inflammation are the primary causes of declining lung function in Cystic Fibrosis (CF) patients. ORKAMBI® (Lumacaftor-Ivacaftor) is an approved combination therapy for Cystic Fibrosis (CF) patients bearing the most common mutation, F508del, in the cystic fibrosis conductance regulator (CFTR) protein. It has been previously shown that ORKAMBI®-mediated rescue of CFTR is reduced by a pre-existing Pseudomonas aeruginosa infection. Here, we show that the infection of F508del-CFTR human bronchial epithelial (HBE) cells with lab strain and four different clinical strains of P. aeruginosa, isolated from the lung sputum of CF patients, decreases CFTR function in a strain-specific manner by 48 to 88%. The treatment of infected cells with antibiotic tobramycin or cationic antimicrobial peptide 6K-F17 was found to decrease clinical strain bacterial growth on HBE cells and restore ORKAMBI®-mediated rescue of F508del-CFTR function. Further, 6K-F17 was found to downregulate the expression of pro-inflammatory cytokines, interleukin (IL)-8, IL-6, and tumor necrosis factor-α in infected HBE cells. The results provide strong evidence for a combination therapy approach involving CFTR modulators and anti-infectives (i.e., tobramycin and/or 6K-F17) to improve their overall efficacy in CF patients.
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Affiliation(s)
- Onofrio Laselva
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (O.L.); (T.A.S.); (C.E.B.)
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Tracy A. Stone
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (O.L.); (T.A.S.); (C.E.B.)
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Christine E. Bear
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (O.L.); (T.A.S.); (C.E.B.)
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Charles M. Deber
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (O.L.); (T.A.S.); (C.E.B.)
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence: ; Tel.: +1-416-813-5924
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Laselva O, Eckford PD, Bartlett C, Ouyang H, Gunawardena TN, Gonska T, Moraes TJ, Bear CE. Functional rescue of c.3846G>A (W1282X) in patient-derived nasal cultures achieved by inhibition of nonsense mediated decay and protein modulators with complementary mechanisms of action. J Cyst Fibros 2019; 19:717-727. [PMID: 31831337 DOI: 10.1016/j.jcf.2019.12.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/26/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND The nonsense mutation, c.3846G>A (aka: W1282X-CFTR) leads to a truncated transcript that is susceptible to nonsense-mediated decay (NMD) and produces a shorter protein that is unstable and lacks normal channel activity in patient-derived tissues. However, if overexpressed in a heterologous expression system, the truncated mutant protein has been shown to mediate CFTR channel function following the addition of potentiators. In this study, we asked if a quadruple combination of small molecules that together inhibit nonsense mediated decay, stabilize both halves of the mutant protein and potentiate CFTR channel activity could rescue the functional expression of W1282X-CFTR in patient derived nasal cultures. METHODS We identified the CFTR domains stabilized by corrector compounds supplied from AbbVie using a fragment based, biochemical approach. Rescue of the channel function of W1282X.-CFTR protein by NMD inhibition and small molecule protein modulators was studied using a bronchial cell line engineered to express W1282X and in primary nasal epithelial cultures derived from four patients homozygous for this mutation. RESULTS We confirmed previous studies showing that inhibition of NMD using the inhibitor: SMG1i, led to an increased abundance of the shorter transcript in a bronchial cell line. Interestingly, on top of SMG1i, treatment with a combination of two new correctors developed by Galapagos/AbbVie (AC1 and AC2-2, separately targeting either the first or second half of CFTR and promoting assembly, significantly increased the potentiated channel activity by the mutant in the bronchial epithelial cell line and in patient-derived nasal epithelial cultures. The average rescue effect in primary cultures was approximately 50% of the regulated chloride conductance measured in non-CF cultures. CONCLUSIONS These studies provide the first in-vitro evidence in patient derived airway cultures that the functional defects incurred by W1282X, has the potential to be effectively repaired pharmacologically.
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Affiliation(s)
- Onofrio Laselva
- Programme in Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, Canada; Department of Physiology, University of Toronto, Toronto, Canada
| | - Paul Dw Eckford
- Programme in Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, Canada
| | - Claire Bartlett
- Programme in Translational Medicine, Hospital for Sick Children Research Institute, Toronto, Canada
| | - Hong Ouyang
- Programme in Translational Medicine, Hospital for Sick Children Research Institute, Toronto, Canada
| | - Tarini Na Gunawardena
- Programme in Translational Medicine, Hospital for Sick Children Research Institute, Toronto, Canada
| | - Tanja Gonska
- Programme in Translational Medicine, Hospital for Sick Children Research Institute, Toronto, Canada; Department of Paediatrics, University of Toronto, Toronto, Canada
| | - Theo J Moraes
- Programme in Translational Medicine, Hospital for Sick Children Research Institute, Toronto, Canada; Department of Paediatrics, University of Toronto, Toronto, Canada.
| | - Christine E Bear
- Programme in Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, Canada; Department of Physiology, University of Toronto, Toronto, Canada; Department of Biochemistry, University of Toronto, Toronto, Canada.
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Phuan PW, Tan JA, Rivera AA, Zlock L, Nielson DW, Finkbeiner WE, Haggie PM, Verkman AS. Nanomolar-potency 'co-potentiator' therapy for cystic fibrosis caused by a defined subset of minimal function CFTR mutants. Sci Rep 2019; 9:17640. [PMID: 31776420 PMCID: PMC6881293 DOI: 10.1038/s41598-019-54158-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/07/2019] [Indexed: 12/11/2022] Open
Abstract
Available CFTR modulators provide no therapeutic benefit for cystic fibrosis (CF) caused by many loss-of-function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, including N1303K. We previously introduced the concept of ‘co-potentiators’ (combination-potentiators) to rescue CFTR function in some minimal function CFTR mutants. Herein, a screen of ~120,000 drug-like synthetic small molecules identified active co-potentiators of pyrazoloquinoline, piperidine-pyridoindole, tetrahydroquinoline and phenylazepine classes, with EC50 down to ~300 nM following initial structure-activity studies. Increased CFTR chloride conductance by up to 8-fold was observed when a co-potentiator (termed ‘Class II potentiator’) was used with a classical potentiator (‘Class I potentiator’) such as VX-770 or GLPG1837. To investigate the range of CFTR mutations benefitted by co-potentiators, 14 CF-associated CFTR mutations were studied in transfected cell models. Co-potentiator efficacy was found for CFTR missense, deletion and nonsense mutations in nucleotide binding domain-2 (NBD2), including W1282X, N1303K, c.3700A > G and Q1313X (with corrector for some mutations). In contrast, CFTR mutations G85E, R334W, R347P, V520F, R560T, A561E, M1101K and R1162X showed no co-potentiator activity, even with corrector. Co-potentiator efficacy was confirmed in primary human bronchial epithelial cell cultures generated from a N1303K homozygous CF subject. The Class II potentiators identified here may have clinical benefit for CF caused by mutations in the NBD2 domain of CFTR.
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Affiliation(s)
- Puay-Wah Phuan
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA.
| | - Joseph-Anthony Tan
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Amber A Rivera
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Lorna Zlock
- Department of Pathology, University of California, San Francisco, San Francisco, CA, USA
| | - Dennis W Nielson
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA, USA
| | - Walter E Finkbeiner
- Department of Pathology, University of California, San Francisco, San Francisco, CA, USA
| | - Peter M Haggie
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Alan S Verkman
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA.,Department of Physiology, University of California, San Francisco, San Francisco, CA, USA
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84
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Serum starvation enhances nonsense mutation readthrough. J Mol Med (Berl) 2019; 97:1695-1710. [PMID: 31786671 DOI: 10.1007/s00109-019-01847-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 10/03/2019] [Accepted: 10/23/2019] [Indexed: 12/13/2022]
Abstract
Of all genetic mutations causing human disease, premature termination codons (PTCs) that result from splicing defaults, insertions, deletions, and point mutations comprise around 30%. From these mutations, around 11% are a substitution of a single nucleotide that change a codon into a premature termination codon. These types of mutations affect several million patients suffering from a large variety of genetic diseases, ranging from relatively common inheritable cancer syndromes to muscular dystrophy or very rare neuro-metabolic disorders. Over the past three decades, genetic and biochemical studies have revealed that certain antibiotics and other synthetic molecules can act as nonsense mutation readthrough-inducing drugs. These compounds bind a specific site on the rRNA and, as a result, the stop codon is misread and an amino acid (that may or may not differ from the wild-type amino acid) is inserted and translation occurs through the premature termination codon. This strategy has great therapeutic potential. Unfortunately, many readthrough agents are toxic and cannot be administered over the extended period usually required for the chronic treatment of genetic diseases. Furthermore, readthrough compounds only restore protein production in very few disease models and the readthrough levels are usually low, typically achieving no more than 5% of normal protein expression. Efforts have been made over the years to overcome these obstacles so that readthrough treatment can become clinically relevant. Here, we present the creation of a stable cell line system that constitutively expresses our dual-reporter vector harboring two cancer initiating nonsense mutations in the adenomatous polyposis coli (APC) gene. This system will be used as an improved screening method for isolation of new nonsense mutation readthrough inducers. Using these cell lines as well as colorectal cancer cell lines, we demonstrate that serum starvation enhances drug-induced readthrough activity, an observation which may prove beneficial in a therapeutic scenario that requires higher levels of the restored protein. KEY MESSAGES: Nonsense mutations affects millions of people worldwide. We have developed a nonsense mutation read-through screening tool. We find that serum starvation enhances antibiotic-induced nonsense mutation read-through. Our results suggest new strategies for enhancing nonsense mutation read-through that may have positive effects on a large number of patients.
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85
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Sasaki S, Sun R, Bui HH, Crosby JR, Monia BP, Guo S. Steric Inhibition of 5' UTR Regulatory Elements Results in Upregulation of Human CFTR. Mol Ther 2019; 27:1749-1757. [PMID: 31351782 PMCID: PMC6822282 DOI: 10.1016/j.ymthe.2019.06.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/20/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive monogenic disease caused by mutations in the CFTR gene. Therapeutic approaches that are focused on correcting CFTR protein face the challenge of the heterogeneity in CFTR mutations and resulting defects. Thus, while several small molecules directed at CFTR show benefit in the clinic for subsets of CF patients, these drugs cannot treat all CF patients. Additionally, the clinical benefit from treatment with these modulators could be enhanced with novel therapies. To address this unmet need, we utilized an approach to increase CFTR protein levels through antisense oligonucleotide (ASO)-mediated steric inhibition of 5′ UTR regulatory elements. We identified ASOs to upregulate CFTR protein expression and confirmed the regulatory role of the sites amenable to ASO-mediated upregulation. Two ASOs were investigated further, and both increased CFTR protein expression and function in cell lines and primary human bronchial epithelial cells with distinct CF genotypes. ASO treatment further increased CFTR function in almost all CF genotypes tested on top of treatment with the FDA approved drug Symdeko (ivacaftor and tezacaftor). Thus, we present a novel approach to CFTR therapeutic intervention, through ASO-mediated modulation of translation.
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Affiliation(s)
- Shruti Sasaki
- Ionis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Rachel Sun
- University of Michigan, Ann Arbor, 500 S State St., Ann Arbor, MI 48109, USA
| | - Huynh-Hoa Bui
- Ionis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Jeff R Crosby
- Ionis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Brett P Monia
- Ionis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Shuling Guo
- Ionis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA.
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Efficient Gene Editing at Major CFTR Mutation Loci. MOLECULAR THERAPY-NUCLEIC ACIDS 2019; 16:73-81. [PMID: 30852378 PMCID: PMC6409404 DOI: 10.1016/j.omtn.2019.02.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 02/11/2019] [Accepted: 02/11/2019] [Indexed: 11/22/2022]
Abstract
Cystic fibrosis (CF) is a lethal autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Nuclease-mediated precise gene editing (PGE) represents a promising therapy for CF, for which an efficient strategy that is free of viral vector, drug selection, and reporter enrichment (VDR free) is desirable. Here we compared different transfection methods (lipofectamine versus electroporation) and formats (plasmid DNA versus ribonucleoprotein) in delivering the CRISPR/Cas9 elements along with single-stranded oligodeoxynucleotides (ssODNs) to clinically relevant cells targeting major CFTR mutation loci. We demonstrate that, among different combinations, electroporation of CRISPR/Cas9 and guide RNA (gRNA) ribonucleoprotein (Cas9 RNP) is the most effective one. By using this VDR-free method, 4.8% to 27.2% efficiencies were achieved in creating dF508, G542X, and G551D mutations in a wild-type induced pluripotent stem cell (iPSC) line. When it is applied to a patient-derived iPSC line carrying the dF508 mutation, a greater than 20% precise correction rate was achieved. As expected, genetic correction leads to the restoration of CFTR function in iPSC-derived proximal lung organoids, as well as in a patient-derived adenocarcinoma cell line CFPAC-1. The present work demonstrates the feasibility of gene editing-based therapeutics toward monogenic diseases such as CF.
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