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Kotsimbos T, Kaye D, Keating D. Pulmonary arterial hypertension and CFTR: the paradox of going forward by tacking sideways! Eur Respir J 2021; 58:58/5/2101839. [PMID: 34824129 DOI: 10.1183/13993003.01839-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 07/13/2021] [Indexed: 11/05/2022]
Affiliation(s)
- Tom Kotsimbos
- Dept of Respiratory Medicine, Alfred Hospital, Central Clinical School, Monash University, Melbourne, Australia .,Dept of Medicine, Central Clinical School, Monash University, Melbourne, Australia
| | - David Kaye
- Dept of Cardiology, Alfred Hospital, Central Clinical School, Monash University, Melbourne, Australia.,Dept of Medicine, Central Clinical School, Monash University, Melbourne, Australia
| | - Dominic Keating
- Dept of Respiratory Medicine, Alfred Hospital, Central Clinical School, Monash University, Melbourne, Australia.,Dept of Medicine, Central Clinical School, Monash University, Melbourne, Australia
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2
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Sharma J, Abbott J, Klaskala L, Zhao G, Birket SE, Rowe SM. A Novel G542X CFTR Rat Model of Cystic Fibrosis Is Sensitive to Nonsense Mediated Decay. Front Physiol 2020; 11:611294. [PMID: 33391025 PMCID: PMC7772197 DOI: 10.3389/fphys.2020.611294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/19/2020] [Indexed: 12/22/2022] Open
Abstract
Nonsense mutations that lead to the insertion of a premature termination codon (PTC) in the cystic fibrosis transmembrane conductance regulator (CFTR) transcript affect 11% of patients with cystic fibrosis (CF) worldwide and are associated with severe disease phenotype. While CF rat models have contributed significantly to our understanding of CF disease pathogenesis, there are currently no rat models available for studying CF nonsense mutations. Here we created and characterized the first homozygous CF rat model that bears the CFTR G542X nonsense mutation in the endogenous locus using CRISPR/Cas9 gene editing. In addition to displaying severe CF manifestations and developmental defects such as reduced growth, abnormal tooth enamel, and intestinal obstruction, CFTR G542X knockin rats demonstrated an absence of CFTR function in tracheal and intestinal sections as assessed by nasal potential difference and transepithelial short-circuit current measurements. Reduced CFTR mRNA levels in the model further suggested sensitivity to nonsense-mediated decay, a pathway elicited by the presence of PTCs that degrades the PTC-bearing transcripts and thus further diminishes the level of CFTR protein. Although functional restoration of CFTR was observed in G542X rat tracheal epithelial cells in response to single readthrough agent therapy, therapeutic efficacy was not observed in G542X knockin rats in vivo. The G542X rat model provides an invaluable tool for the identification and in vivo validation of potential therapies for CFTR nonsense mutations.
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Affiliation(s)
- Jyoti Sharma
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Joseph Abbott
- Horizon Discovery Group, PLC, St. Louis, MO, United States
| | | | - Guojun Zhao
- Horizon Discovery Group, PLC, St. Louis, MO, United States
| | - Susan E. Birket
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Steven M. Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
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3
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Birket SE, Davis JM, Fernandez-Petty CM, Henderson AG, Oden AM, Tang L, Wen H, Hong J, Fu L, Chambers A, Fields A, Zhao G, Tearney GJ, Sorscher EJ, Rowe SM. Ivacaftor Reverses Airway Mucus Abnormalities in a Rat Model Harboring a Humanized G551D-CFTR. Am J Respir Crit Care Med 2020; 202:1271-1282. [PMID: 32584141 PMCID: PMC7605185 DOI: 10.1164/rccm.202002-0369oc] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/22/2020] [Indexed: 12/25/2022] Open
Abstract
Rationale: Animal models have been highly informative for understanding the characteristics, onset, and progression of cystic fibrosis (CF) lung disease. In particular, the CFTR-/- rat has revealed insights into the airway mucus defect characteristic of CF but does not replicate a human-relevant CFTR (cystic fibrosis transmembrane conductance regulator) variant.Objectives: We hypothesized that a rat expressing a humanized version of CFTR and harboring the ivacaftor-sensitive variant G551D could be used to test the impact of CFTR modulators on pathophysiologic development and correction.Methods: In this study, we describe a humanized-CFTR rat expressing the G551D variant obtained by zinc finger nuclease editing of a human complementary DNA superexon, spanning exon 2-27, with a 5' insertion site into the rat gene just beyond intron 1. This targeted insertion takes advantage of the endogenous rat promoter, resulting in appropriate expression compared with wild-type animals.Measurements and Main Results: The bioelectric phenotype of the epithelia recapitulates the expected absence of CFTR activity, which was restored with ivacaftor. Large airway defects, including depleted airway surface liquid and periciliary layers, delayed mucus transport rates, and increased mucus viscosity, were normalized after the administration of ivacaftor.Conclusions: This model is useful to understand the mechanisms of disease and the extent of pathology reversal with CFTR modulators.
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Affiliation(s)
| | | | | | | | | | | | - Hui Wen
- Cystic Fibrosis Research Center, and
| | - Jeong Hong
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Lianwu Fu
- Cystic Fibrosis Research Center, and
- Cell, Developmental, and Integrated Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | | | - Alvin Fields
- Horizon Discovery Group PLC, St. Louis, Missouri; and
| | - Gojun Zhao
- Horizon Discovery Group PLC, St. Louis, Missouri; and
| | - Guillermo J. Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Eric J. Sorscher
- Cell, Developmental, and Integrated Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Steven M. Rowe
- Department of Medicine
- Cystic Fibrosis Research Center, and
- Cell, Developmental, and Integrated Biology, University of Alabama at Birmingham, Birmingham, Alabama
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4
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Lin VY, Fain MD, Jackson PL, Berryhill TF, Wilson LS, Mazur M, Barnes SJ, Blalock JE, Raju SV, Rowe SM. Vaporized E-Cigarette Liquids Induce Ion Transport Dysfunction in Airway Epithelia. Am J Respir Cell Mol Biol 2020; 61:162-173. [PMID: 30576219 DOI: 10.1165/rcmb.2017-0432oc] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cigarette smoking is associated with chronic obstructive pulmonary disease and chronic bronchitis. Acquired ion transport abnormalities, including cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction, caused by cigarette smoking have been proposed as potential mechanisms for mucus obstruction in chronic bronchitis. Although e-cigarette use is popular and perceived to be safe, whether it harms the airways via mechanisms altering ion transport remains unclear. In the present study, we sought to determine if e-cigarette vapor, like cigarette smoke, has the potential to induce acquired CFTR dysfunction, and to what degree. Electrophysiological methods demonstrated reduced chloride transport caused by vaporized e-cigarette liquid or vegetable glycerin at various exposures (30 min, 57.2% and 14.4% respectively, vs. control; P < 0.0001), but not by unvaporized liquid (60 min, 17.6% vs. untreated), indicating that thermal degradation of these products is required to induce the observed defects. We also observed reduced ATP-dependent responses (-10.8 ± 3.0 vs. -18.8 ± 5.1 μA/cm2 control) and epithelial sodium channel activity (95.8% reduction) in primary human bronchial epithelial cells after 5 minutes, suggesting that exposures dramatically inhibit epithelial ion transport beyond CFTR, even without diminished transepithelial resistance or cytotoxicity. Vaporizing e-cigarette liquid produced reactive aldehydes, including acrolein (shown to induce acquired CFTR dysfunction), as quantified by mass spectrometry, demonstrating that respiratory toxicants in cigarette smoke can also be found in e-cigarette vapor (30 min air, 224.5 ± 15.99; unvaporized liquid, 284.8 ± 35.03; vapor, 54,468 ± 3,908 ng/ml; P < 0.0001). E-cigarettes can induce ion channel dysfunction in airway epithelial cells, partly through acrolein production. These findings indicate a heretofore unknown toxicity of e-cigarette use known to be associated with chronic bronchitis onset and progression, as well as with chronic obstructive pulmonary disease severity.
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Affiliation(s)
| | | | | | - Taylor F Berryhill
- 2Pharmacology/Toxicology and Targeted Metabolomics and Proteomics Laboratory
| | - Landon S Wilson
- 2Pharmacology/Toxicology and Targeted Metabolomics and Proteomics Laboratory
| | | | - Stephen J Barnes
- 2Pharmacology/Toxicology and Targeted Metabolomics and Proteomics Laboratory
| | | | | | - Steven M Rowe
- 1Department of Medicine.,3Gregory J. Fleming Cystic Fibrosis Center.,4Department of Pediatrics, and.,5Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
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5
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Rasmussen LW, Stanford D, Patel K, Raju SV. Evaluation of secondhand smoke effects on CFTR function in vivo. Respir Res 2020; 21:70. [PMID: 32192506 PMCID: PMC7082971 DOI: 10.1186/s12931-020-1324-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/17/2020] [Indexed: 01/01/2023] Open
Affiliation(s)
- Lawrence W Rasmussen
- Departments of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
- Environmental Health Sciences, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Denise Stanford
- Departments of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
- Gregory Fleming James Cystic Fibrosis Research Center, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Krina Patel
- Departments of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - S Vamsee Raju
- Departments of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA.
- Gregory Fleming James Cystic Fibrosis Research Center, The University of Alabama at Birmingham, Birmingham, AL, USA.
- Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, USA.
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McCormick LL, Phillips SE, Kaza N, Tang LP, Rasmussen L, Byzek SA, Raju SV, Rowe SM. Maternal Smoking Induces Acquired CFTR Dysfunction in Neonatal Rats. Am J Respir Crit Care Med 2019; 198:672-674. [PMID: 29979606 DOI: 10.1164/rccm.201805-0827le] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
| | | | - Niroop Kaza
- 1 University of Alabama at Birmingham Birmingham, Alabama
| | - Li Ping Tang
- 1 University of Alabama at Birmingham Birmingham, Alabama
| | | | | | - S Vamsee Raju
- 1 University of Alabama at Birmingham Birmingham, Alabama
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