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Jarvis MF. Decatastrophizing research irreproducibility. Biochem Pharmacol 2024:116090. [PMID: 38408680 DOI: 10.1016/j.bcp.2024.116090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 02/03/2024] [Accepted: 02/23/2024] [Indexed: 02/28/2024]
Abstract
The reported inability to replicate research findings from the published literature precipitated extensive efforts to identify and correct perceived deficiencies in the execution and reporting of biomedical research. Despite these efforts, quantification of the magnitude of irreproducible research or the effectiveness of associated remediation initiatives, across diverse biomedical disciplines, has made little progress over the last decade. The idea that science is self-correcting has been further challenged in recent years by the proliferation of unverified or fraudulent scientific content generated by predatory journals, paper mills, pre-print server postings, and the inappropriate use of artificial intelligence technologies. The degree to which the field of pharmacology has been negatively impacted by these evolving pressures is unknown. Regardless of these ambiguities, pharmacology societies and their associated journals have championed best practices to enhance the experimental rigor and reporting of pharmacological research. The value of transparent and independent validation of raw data generation and its analysis in basic and clinical research is exemplified by the discovery, development, and approval of Highly Effective Modulator Therapy (HEMT) for Cystic Fibrosis (CF) patients. This provides a didactic counterpoint to concerns regarding the current state of biomedical research. Key features of this important therapeutic advance include objective construction of basic and translational research hypotheses, associated experimental designs, and validation of experimental effect sizes with quantitative alignment to meaningful clinical endpoints with input from the FDA, which enhanced scientific rigor and transparency with real world deliverables for patients in need.
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Affiliation(s)
- Michael F Jarvis
- Department of Pharmaceutical Sciences, University of Illinois-Chicago, USA.
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2
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Joynt AT, Kavanagh EW, Newby GA, Mitchell S, Eastman AC, Paul KC, Bowling AD, Osorio DL, Merlo CA, Patel SU, Raraigh KS, Liu DR, Sharma N, Cutting GR. Protospacer modification improves base editing of a canonical splice site variant and recovery of CFTR function in human airway epithelial cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 33:335-350. [PMID: 37547293 PMCID: PMC10400809 DOI: 10.1016/j.omtn.2023.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 06/26/2023] [Indexed: 08/08/2023]
Abstract
Canonical splice site variants affecting the 5' GT and 3' AG nucleotides of introns result in severe missplicing and account for about 10% of disease-causing genomic alterations. Treatment of such variants has proven challenging due to the unstable mRNA or protein isoforms that typically result from disruption of these sites. Here, we investigate CRISPR-Cas9-mediated adenine base editing for such variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. We validate a CFTR expression minigene (EMG) system for testing base editing designs for two different targets. We then use the EMG system to test non-standard single-guide RNAs with either shortened or lengthened protospacers to correct the most common cystic fibrosis-causing variant in individuals of African descent (c.2988+1G>A). Varying the spacer region length allowed placement of the editing window in a more efficient context and enabled use of alternate protospacer adjacent motifs. Using these modifications, we restored clinically significant levels of CFTR function to human airway epithelial cells from two donors bearing the c.2988+1G>A variant.
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Affiliation(s)
- Anya T. Joynt
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - Erin W. Kavanagh
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - Gregory A. Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Shakela Mitchell
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - Alice C. Eastman
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - Kathleen C. Paul
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - Alyssa D. Bowling
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - Derek L. Osorio
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - Christian A. Merlo
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, MD 21287, USA
| | - Shivani U. Patel
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, MD 21287, USA
| | - Karen S. Raraigh
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - David R. Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Neeraj Sharma
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
| | - Garry R. Cutting
- Department of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, MD 21205, USA
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Dawood SN, Rabih AM, Niaj A, Raman A, Uprety M, Calero MJ, Villanueva MRB, Joshaghani N, Villa N, Badla O, Goit R, Saddik SE, Mohammed L. Newly Discovered Cutting-Edge Triple Combination Cystic Fibrosis Therapy: A Systematic Review. Cureus 2022; 14:e29359. [DOI: 10.7759/cureus.29359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/20/2022] [Indexed: 11/05/2022] Open
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Fajac I, Sermet-Gaudelus I. Emerging medicines to improve the basic defect in cystic fibrosis. Expert Opin Emerg Drugs 2022; 27:229-239. [PMID: 35731915 DOI: 10.1080/14728214.2022.2092612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Cystic fibrosis (CF) is a severe autosomal recessive disorder featuring exocrine pancreatic insufficiency and bronchiectasis. It is caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) encoding the CFTR protein, which is an anion channel. CF treatment has long been based only on intensive symptomatic treatment. During the last 10 years, new drugs called CFTR modulators aiming at restoring the CFTR protein function have become available, and they will benefit around 80% of patients with CF. However, more than 10% of CFTR mutations do not produce any CFTR protein for CFTR modulators to act upon. AREAS COVERED The development of CFTR modulators and their effectiveness in patients with CF will be reviewed. Then, the different strategies to treat patients bearing mutations non-responsive to CFTR modulators will be covered. They comprise DNA- and RNA-based therapies, readthrough agents for nonsense mutations, and cell-based therapies. EXPERT OPINION CF disease has changed tremendously since the advent of CFTR modulators. For mutations that are not amenable to CFTR modulators, new approaches that are being developed benefit from advances in molecular therapy, but many challenges will have to be solved before they can be safely translated to patients.
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Affiliation(s)
- Isabelle Fajac
- AP-HP. Centre - Université Paris Cité; Hôpital Cochin, Centre de Référence Maladie Rare- Mucoviscidose, Paris, France.,Faculté de Médecine, Université de Paris, Paris, France
| | - Isabelle Sermet-Gaudelus
- Faculté de Médecine, Université de Paris, Paris, France.,Institut Necker Enfants Malades, INSERM U 1151, Paris, France.,AP-HP. Centre - Université Paris Cité; Hôpital Necker Enfants Malades, Centre de Référence Maladie Rare - Mucoviscidose, Paris, France
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Holliday ZM, Launspach JL, Durairaj L, Singh PK, Zabner J, Stoltz DA. Effects of Tham Nasal Alkalinization on Airway Microbial Communities: A Pilot Study in Non-CF and CF Adults. Ann Otol Rhinol Laryngol 2022; 131:1013-1020. [PMID: 34674574 PMCID: PMC9021322 DOI: 10.1177/00034894211051814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES In cystic fibrosis (CF), loss of CFTR-mediated bicarbonate secretion reduces the airway surface liquid (ASL) pH causing airway host defense defects. Aerosolized sodium bicarbonate can reverse these defects, but its effects are short-lived. Aerosolized tromethamine (THAM) also raises the ASL pH but its effects are much longer lasting. In this pilot study, we tested the hypothesis that nasally administered THAM would alter the nasal bacterial composition in adults with and without CF. METHODS Subjects (n = 32 total) received intranasally administered normal saline or THAM followed by a wash out period prior to receiving the other treatment. Nasal bacterial cultures were obtained prior to and after each treatment period. RESULTS At baseline, nasal swab bacterial counts were similar between non-CF and CF subjects, but CF subjects had reduced microbial diversity. Both nasal saline and THAM were well-tolerated. In non-CF subjects, nasal airway alkalinization decreased both the total bacterial density and the gram-positive bacterial species recovered. In both non-CF and CF subjects, THAM decreased the amount of Corynebacterium accolens detected, but increased the amount of Corynebacterium pseudodiphtheriticum recovered on nasal swabs. A reduction in Staphylococcus aureus nasal colonization was also found in subjects who grew C. pseudodiphtheriticum. CONCLUSIONS This study shows that aerosolized THAM is safe and well-tolerated and that nasal airway alkalinization alters the composition of mucosal bacterial communities. CLINICAL TRIAL REGISTRATION NCT00928135 (https://clinicaltrials.gov/ct2/show/NCT00928135).
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Affiliation(s)
- Zachary M Holliday
- Department of Internal Medicine, University of Iowa, Roy J and Lucille A. Carver College of Medicine, Iowa City, IA, USA
| | - Janice L Launspach
- Department of Internal Medicine, University of Iowa, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - Lakshmi Durairaj
- Department of Internal Medicine, University of Iowa, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - Pradeep K Singh
- Departments of Microbiology and Medicine, University of Washington, Seattle, WA, USA
| | - Joseph Zabner
- Department of Internal Medicine and Pappajohn Biomedical Institute, University of Iowa, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - David A Stoltz
- Departments of Biomedical Engineering, Molecular Physiology and Biophysics, Internal Medicine and Pappajohn Biomedical Institute, University of Iowa, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
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Wang C, Anglès F, Balch WE. Triangulating variation in the population to define mechanisms for precision management of genetic disease. Structure 2022; 30:1190-1207.e5. [PMID: 35714602 PMCID: PMC9357173 DOI: 10.1016/j.str.2022.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 04/18/2022] [Accepted: 05/17/2022] [Indexed: 10/18/2022]
Abstract
To understand mechanistically how the protein fold is shaped by therapeutics to inform precision management of disease, we developed variation-capture (VarC) mapping. VarC triangulates sparse sequence variation information found in the population using Gaussian process regression (GPR)-based machine learning to define the combined pairwise-residue interactions contributing to dynamic protein function in the individual in response to therapeutics. Using VarC mapping, we now reveal the pairwise-residue covariant relationships across the entire protein fold of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) to define the molecular mechanisms of clinically approved CF chemical modulators. We discover an energetically destabilized covariant core containing a di-acidic YKDAD endoplasmic reticulum (ER) exit code that is only weakly corrected by current therapeutics. Our results illustrate that VarC provides a generalizable tool to triangulate information from genetic variation in the population to mechanistically discover therapeutic strategies that guide precision management of the individual.
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Affiliation(s)
- Chao Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA 92037, USA
| | - Frédéric Anglès
- Department of Molecular Medicine, Scripps Research, La Jolla, CA 92037, USA
| | - William E Balch
- Department of Molecular Medicine, Scripps Research, La Jolla, CA 92037, USA.
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Knoppers T, Cosquer M, Hagan J, Nguyen MT, Knoppers BM. “The Stakes Are Higher”- Patient and Caregiver Perspectives on Cystic Fibrosis Research and Personalized Medicine. Front Med (Lausanne) 2022; 9:841887. [PMID: 35402437 PMCID: PMC8984098 DOI: 10.3389/fmed.2022.841887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/14/2022] [Indexed: 11/18/2022] Open
Abstract
Introduction Making bench to bedside advances in cystic fibrosis (CF) care requires the sustained engagement and trust of people living with CF. However, there is a scarcity of studies exploring their concerns and priorities regarding research and its end products. The aim of this qualitative study was to generate empirical evidence regarding patient and caregiver perspectives on cystic fibrosis research and personalized medicine to foster developments in translational research in Canada. Methods A total of 15 focus groups were conducted, engaging 22 adults with CF and 18 caregivers (e.g., parents, siblings and partners) living in Canada. Inductive thematic analysis relied on an iterative process involving themes derived from both participant meaning-making and existing scientific literature. Participant perspectives were considered along intrapersonal, intracommunity, interpersonal, and structural lines. Results Overall, participants described a relationship to CF research inextricable from the lived experience of CF as a lifelong progressive and terminal disease and from the goal of advancing medical science. They were enthusiastic and excited about the emergence of CFTR modulators, although they had some knowledge gaps regarding the associated research. They largely spoke to positive experiences with researcher communication but had feedback regarding informed consent processes and the return of study results. Participants also voiced concerns about structural access barriers to research and to its end products. Extensive histories of research participation, a relatively small and intercommunicative CF community, and structural overlap between research and care settings contributed to their perspectives and priorities. Conclusion Study findings are valuable for researchers and policy-makers in CF and rare or progressive diseases more broadly. Continuing to solicit and listen to the voices of patients and caregivers is crucial for research ethics and the translation of new therapies in the area of personalized medicine.
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Affiliation(s)
- Terese Knoppers
- Centre of Genomics and Policy, McGill University, Montreal, QC, Canada
- *Correspondence: Terese Knoppers,
| | - Marie Cosquer
- Centre of Genomics and Policy, McGill University, Montreal, QC, Canada
| | - Julie Hagan
- Department of Sociology, Laval University, Quebec, QC, Canada
| | - Minh Thu Nguyen
- Centre of Genomics and Policy, McGill University, Montreal, QC, Canada
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Morgan R, Manfredi C, Easley KF, Watkins LD, Hunt WR, Goudy SL, Sorscher EJ, Koval M, Molina SA. A medium composition containing normal resting glucose that supports differentiation of primary human airway cells. Sci Rep 2022; 12:1540. [PMID: 35087167 PMCID: PMC8795386 DOI: 10.1038/s41598-022-05446-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 01/10/2022] [Indexed: 02/07/2023] Open
Abstract
Primary cells isolated from the human respiratory tract are the state-of-the-art for in vitro airway epithelial cell research. Airway cell isolates require media that support expansion of cells in a basal state to maintain the capacity for differentiation as well as proper cellular function. By contrast, airway cell differentiation at an air-liquid interface (ALI) requires a distinct medium formulation that typically contains high levels of glucose. Here, we expanded and differentiated human basal cells isolated from the nasal and conducting airway to a mature mucociliary epithelial cell layer at ALI using a medium formulation containing normal resting glucose levels. Of note, bronchial epithelial cells expanded and differentiated in normal resting glucose medium showed insulin-stimulated glucose uptake which was inhibited by high glucose concentrations. Normal glucose containing ALI also enabled differentiation of nasal and tracheal cells that showed comparable electrophysiological profiles when assessed for cystic fibrosis transmembrane conductance regulator (CFTR) function and that remained responsive for up to 7 weeks in culture. These data demonstrate that normal glucose containing medium supports differentiation of primary nasal and lung epithelial cells at ALI, is well suited for metabolic studies, and avoids pitfalls associated with exposure to high glucose.
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Affiliation(s)
- Rachel Morgan
- Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, 205 Whitehead Building, 615 Michael Street, Atlanta, GA, 30322, USA
| | - Candela Manfredi
- Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Division of Pulmonary, Allergy & Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Kristen F Easley
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, 205 Whitehead Building, 615 Michael Street, Atlanta, GA, 30322, USA
| | - Lionel D Watkins
- Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, 205 Whitehead Building, 615 Michael Street, Atlanta, GA, 30322, USA
| | - William R Hunt
- Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, 205 Whitehead Building, 615 Michael Street, Atlanta, GA, 30322, USA
| | - Steven L Goudy
- Division of Pulmonary, Allergy & Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Eric J Sorscher
- Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Division of Pulmonary, Allergy & Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Michael Koval
- Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, 205 Whitehead Building, 615 Michael Street, Atlanta, GA, 30322, USA.
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| | - Samuel A Molina
- Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, 205 Whitehead Building, 615 Michael Street, Atlanta, GA, 30322, USA
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Cottrill KA, Giacalone VD, Margaroli C, Bridges RJ, Koval M, Tirouvanziam R, McCarty NA. Mechanistic analysis and significance of sphingomyelinase-mediated decreases in transepithelial CFTR currents in nHBEs. Physiol Rep 2021; 9:e15023. [PMID: 34514718 PMCID: PMC8436056 DOI: 10.14814/phy2.15023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 07/02/2021] [Indexed: 12/15/2022] Open
Abstract
Loss of function of the cystic fibrosis transmembrane conductance regulator (CFTR) causes cystic fibrosis (CF). In the lungs, this manifests as immune cell infiltration and bacterial infections, leading to tissue destruction. Previous work has determined that acute bacterial sphingomyelinase (SMase) decreases CFTR function in bronchial epithelial cells from individuals without CF (nHBEs) and with CF (cfHBEs, homozygous ΔF508-CFTR mutation). This study focuses on exploring the mechanisms underlying this effect. SMase increased the abundance of dihydroceramides, a result mimicked by blockade of ceramidase enzyme using ceranib-1, which also decreased CFTR function. The SMase-mediated inhibitory mechanism did not involve the reduction of cellular CFTR abundance or removal of CFTR from the apical surface, nor did it involve the activation of 5' adenosine monophosphate-activated protein kinase. In order to determine the pathological relevance of these sphingolipid imbalances, we evaluated the sphingolipid profiles of cfHBEs and cfHNEs (nasal) as compared to non-CF controls. Sphingomyelins, ceramides, and dihydroceramides were largely increased in CF cells. Correction of ΔF508-CFTR trafficking with VX445 + VX661 decreased some sphingomyelins and all ceramides, but exacerbated increases in dihydroceramides. Additional treatment with the CFTR potentiator VX770 did not affect these changes, suggesting rescue of misfolded CFTR was sufficient. We furthermore determined that cfHBEs express more acid-SMase protein than nHBEs. Lastly, we determined that airway-like neutrophils, which are increased in the CF lung, secrete acid-SMase. Identifying the mechanism of SMase-mediated inhibition of CFTR will be important, given the imbalance of sphingolipids in CF cells and the secretion of acid-SMase from cell types relevant to CF.
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Affiliation(s)
- Kirsten A. Cottrill
- Molecular and Systems Pharmacology PhD ProgramEmory UniversityAtlantaGeorgiaUSA
| | - Vincent D. Giacalone
- Immunology and Molecular Pathogenesis PhD ProgramEmory UniversityAtlantaGeorgiaUSA
| | - Camilla Margaroli
- Department of MedicineDivision of PulmonaryAllergy & Critical Care MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
- Program in Protease/Matrix BiologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Robert J. Bridges
- Department of Physiology and BiophysicsCenter for Genetic DiseasesChicago Medical SchoolNorth ChicagoIllinoisUSA
| | - Michael Koval
- Department of MedicineDivision of Pulmonary, Allergy, Critical Care and Sleep Medicine and Department of Cell BiologyEmory UniversityAtlantaGeorgiaUSA
| | - Rabindra Tirouvanziam
- Department of Pediatrics and Children’s Healthcare of AtlantaCenter for Cystic Fibrosis and Airways Disease ResearchEmory University School of MedicineAtlantaGeorgiaUSA
| | - Nael A. McCarty
- Molecular and Systems Pharmacology PhD ProgramEmory UniversityAtlantaGeorgiaUSA
- Department of Pediatrics and Children’s Healthcare of AtlantaCenter for Cystic Fibrosis and Airways Disease ResearchEmory University School of MedicineAtlantaGeorgiaUSA
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Cottrill KA, Peterson RJ, Lewallen CF, Koval M, Bridges RJ, McCarty NA. Sphingomyelinase decreases transepithelial anion secretion in airway epithelial cells in part by inhibiting CFTR-mediated apical conductance. Physiol Rep 2021; 9:e14928. [PMID: 34382377 PMCID: PMC8358481 DOI: 10.14814/phy2.14928] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 12/11/2022] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel whose dysfunction causes cystic fibrosis (CF). The loss of CFTR function in pulmonary epithelial cells causes surface dehydration, mucus build-up, inflammation, and bacterial infections that lead to lung failure. Little has been done to evaluate the effects of lipid perturbation on CFTR activity, despite CFTR residing in the plasma membrane. This work focuses on the acute effects of sphingomyelinase (SMase), a bacterial virulence factor secreted by CF relevant airway bacteria which degrades sphingomyelin into ceramide and phosphocholine, on the electrical circuitry of pulmonary epithelial monolayers. We report that basolateral SMase decreases CFTR-mediated transepithelial anion secretion in both primary bronchial and tracheal epithelial cells from explant tissue, with current CFTR modulators unable to rescue this effect. Focusing on primary cells, we took a holistic ion homeostasis approach to determine a cause for reduced anion secretion following SMase treatment. Using impedance analysis, we determined that basolateral SMase inhibits apical and basolateral conductance in non-CF primary cells without affecting paracellular permeability. In CF primary airway cells, correction with clinically relevant CFTR modulators did not prevent SMase-mediated inhibition of CFTR currents. Furthermore, SMase was found to inhibit only apical conductance in these cells. Future work should determine the mechanism for SMase-mediated inhibition of CFTR currents, and further explore the clinical relevance of SMase and sphingolipid imbalances.
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Affiliation(s)
- Kirsten A. Cottrill
- Molecular and Systems Pharmacology PhD ProgramEmory UniversityAtlantaGeorgiaUSA
| | - Raven J. Peterson
- Biochemistry, Cell, and Developmental Biology PhD ProgramEmory UniversityAtlantaGeorgiaUSA
| | - Colby F. Lewallen
- Georgia Institute of TechnologyG.W. Woodruff School of Mechanical EngineeringAtlantaGeorgiaUSA
| | - Michael Koval
- Division of Pulmonary, Allergy, Critical Care and Sleep MedicineDepartment of MedicineEmory UniversityAtlantaGeorgiaUSA
- Department of Cell BiologyEmory UniversityAtlantaGeorgiaUSA
| | - Robert J. Bridges
- Department of Physiology and BiophysicsCenter for Genetic DiseasesChicago Medical SchoolNorth Chicago, IllinoisUSA
| | - Nael A. McCarty
- Molecular and Systems Pharmacology PhD ProgramEmory UniversityAtlantaGeorgiaUSA
- Department of Pediatrics and Children’s Healthcare of AtlantaCenter for Cystic Fibrosis and Airways Disease ResearchEmory University School of MedicineAtlantaGeorgiaUSA
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Cui G, Cottrill KA, Strickland KM, Mashburn SA, Koval M, McCarty NA. Alteration of Membrane Cholesterol Content Plays a Key Role in Regulation of Cystic Fibrosis Transmembrane Conductance Regulator Channel Activity. Front Physiol 2021; 12:652513. [PMID: 34163370 PMCID: PMC8215275 DOI: 10.3389/fphys.2021.652513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/23/2021] [Indexed: 11/30/2022] Open
Abstract
Altered cholesterol homeostasis in cystic fibrosis patients has been reported, although controversy remains. As a major membrane lipid component, cholesterol modulates the function of multiple ion channels by complicated mechanisms. However, whether cholesterol directly modulates cystic fibrosis transmembrane conductance regulator (CFTR) channel function remains unknown. To answer this question, we determined the effects of changing plasma membrane cholesterol levels on CFTR channel function utilizing polarized fischer rat thyroid (FRT) cells and primary human bronchial epithelial (HBE) cells. Treatment with methyl-β-cyclodextrin (MβCD) significantly reduced total cholesterol content in FRT cells, which significantly decreased forskolin (FSK)-mediated activation of both wildtype (WT-) and P67L-CFTR. This effect was also seen in HBE cells expressing WT-CFTR. Cholesterol modification by cholesterol oxidase and cholesterol esterase also distinctly affected activation of CFTR by FSK. In addition, alteration of cholesterol increased the potency of VX-770, a clinically used potentiator of CFTR, when both WT- and P67L-CFTR channels were activated at low FSK concentrations; this likely reflects the apparent shift in the sensitivity of WT-CFTR to FSK after alteration of membrane cholesterol. These results demonstrate that changes in the plasma membrane cholesterol level significantly modulate CFTR channel function and consequently may affect sensitivity to clinical therapeutics in CF patients.
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Affiliation(s)
- Guiying Cui
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Kirsten A Cottrill
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Kerry M Strickland
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Sarah A Mashburn
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Michael Koval
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Nael A McCarty
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, United States
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12
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The Equitable Implementation of Cystic Fibrosis Personalized Medicines in Canada. J Pers Med 2021; 11:jpm11050382. [PMID: 34067090 PMCID: PMC8151662 DOI: 10.3390/jpm11050382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/04/2021] [Accepted: 05/04/2021] [Indexed: 11/16/2022] Open
Abstract
This article identifies the potential sources of inequity in three stages of integrating cystic fibrosis personalized medicines into the Canadian healthcare system and proposes mitigating strategies: (1) clinical research and diagnostic testing; (2) regulatory oversight and market authorization; and (3) implementation into the healthcare system. There is concern that differential access will cast a dark shadow over personalized medicine by stratifying the care that groups of patients will receive-not only based on their genetic profiles, but also on the basis of their socioeconomic status. Furthermore, there is a need to re-evaluate regulatory and market approval mechanisms to accommodate the unique nature of personalized medicines. Physical and financial accessibility ought to be remedied before personalized medicines can be equitably delivered to patients. This article identifies the socio-ethical and legal challenges at each stage and recommends mitigating policy solutions.
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13
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Eastman AC, Pace RG, Dang H, Aksit MA, Vecchio-Pagán B, Lam ATN, O'Neal WK, Blackman SM, Knowles MR, Cutting GR. SLC26A9 SNP rs7512462 is not associated with lung disease severity or lung function response to ivacaftor in cystic fibrosis patients with G551D-CFTR. J Cyst Fibros 2021; 20:851-856. [PMID: 33674211 DOI: 10.1016/j.jcf.2021.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/05/2021] [Accepted: 02/10/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND The CFTR modulator ivacaftor has been variably effective in treating individuals with cystic fibrosis (CF) who harbor CFTR gating variants such as G551D, as well as other classes of CFTR variants when used with other modulators. Because CFTR genotype does not fully explain this variability, defining genetic modifiers of response to modulator therapy is of particular interest to the field of individualized CF drug therapy. Previous studies have proposed that a variant in SLC26A9 (rs7512462) is associated with lung disease severity and with response to treatment with ivacaftor in individuals with CF who carry G551D or gating variants. METHODS Given the implications for CF treatment, we re-examined the reported associations in three cohorts; patients enrolled in the Twin and Siblings study at Johns Hopkins University, the CF modifier study at the University of North Carolina at Chapel Hill, and the prospective G551D Observational (GOAL) study. The GOAL study was specifically designed to measure lung function response to ivacaftor. RESULTS We find no association between SLC26A9 (rs7512462) genotype and lung disease severity (n = 272) or change in lung function at one-, three-, and six-month intervals following ivacaftor treatment(n = 141) in individuals with CF who carry at least one G551D variant. CONCLUSIONS Our inability to replicate this association indicates that rs7512462 genotype should not be used in treatment decisions.
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Affiliation(s)
- Alice C Eastman
- Department of Genetic Medicine, Johns Hopkins University (JHU), Baltimore, MD, 21205, USA
| | - Rhonda G Pace
- University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, 27599, USA
| | - Hong Dang
- University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, 27599, USA
| | - Melis Atalar Aksit
- Department of Genetic Medicine, Johns Hopkins University (JHU), Baltimore, MD, 21205, USA
| | - Briana Vecchio-Pagán
- Department of Genetic Medicine, Johns Hopkins University (JHU), Baltimore, MD, 21205, USA
| | - Anh-Thu N Lam
- Department of Genetic Medicine, Johns Hopkins University (JHU), Baltimore, MD, 21205, USA
| | - Wanda K O'Neal
- University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, 27599, USA
| | - Scott M Blackman
- Department of Genetic Medicine, Johns Hopkins University (JHU), Baltimore, MD, 21205, USA
| | - Michael R Knowles
- University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, 27599, USA.
| | - Garry R Cutting
- Department of Genetic Medicine, Johns Hopkins University (JHU), Baltimore, MD, 21205, USA.
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14
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Rauscher R, Bampi GB, Guevara-Ferrer M, Santos LA, Joshi D, Mark D, Strug LJ, Rommens JM, Ballmann M, Sorscher EJ, Oliver KE, Ignatova Z. Positive epistasis between disease-causing missense mutations and silent polymorphism with effect on mRNA translation velocity. Proc Natl Acad Sci U S A 2021; 118:e2010612118. [PMID: 33468668 PMCID: PMC7848603 DOI: 10.1073/pnas.2010612118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Epistasis refers to the dependence of a mutation on other mutation(s) and the genetic context in general. In the context of human disorders, epistasis complicates the spectrum of disease symptoms and has been proposed as a major contributor to variations in disease outcome. The nonadditive relationship between mutations and the lack of complete understanding of the underlying physiological effects limit our ability to predict phenotypic outcome. Here, we report positive epistasis between intragenic mutations in the cystic fibrosis transmembrane conductance regulator (CFTR)-the gene responsible for cystic fibrosis (CF) pathology. We identified a synonymous single-nucleotide polymorphism (sSNP) that is invariant for the CFTR amino acid sequence but inverts translation speed at the affected codon. This sSNP in cis exhibits positive epistatic effects on some CF disease-causing missense mutations. Individually, both mutations alter CFTR structure and function, yet when combined, they lead to enhanced protein expression and activity. The most robust effect was observed when the sSNP was present in combination with missense mutations that, along with the primary amino acid change, also alter the speed of translation at the affected codon. Functional studies revealed that synergistic alteration in ribosomal velocity is the underlying mechanism; alteration of translation speed likely increases the time window for establishing crucial domain-domain interactions that are otherwise perturbed by each individual mutation.
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Affiliation(s)
- Robert Rauscher
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Giovana B Bampi
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Marta Guevara-Ferrer
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Leonardo A Santos
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Disha Joshi
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322
- Children's Healthcare of Atlanta, Atlanta, GA 30322
| | - David Mark
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Lisa J Strug
- Program in Genetics & Genome Biology, The Hospital for Sick Children, Toronto M5G 0A4, Canada
- Department of Statistical Sciences, Computer Science and Division of Biostatistics, University of Toronto, Toronto M5G 0A4, Canada
| | - Johanna M Rommens
- Program in Genetics & Genome Biology, The Hospital for Sick Children, Toronto M5G 0A4, Canada
| | | | - Eric J Sorscher
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322
- Children's Healthcare of Atlanta, Atlanta, GA 30322
| | - Kathryn E Oliver
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322
- Children's Healthcare of Atlanta, Atlanta, GA 30322
| | - Zoya Ignatova
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, 20146 Hamburg, Germany;
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15
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Da Silva Sanchez A, Paunovska K, Cristian A, Dahlman JE. Treating Cystic Fibrosis with mRNA and CRISPR. Hum Gene Ther 2020; 31:940-955. [PMID: 32799680 PMCID: PMC7495921 DOI: 10.1089/hum.2020.137] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/13/2020] [Indexed: 12/16/2022] Open
Abstract
Less than 20% of the protein coding genome is thought to be targetable using small molecules. mRNA therapies are not limited in the same way since in theory, they can silence or edit any gene by encoding CRISPR nucleases, or alternatively, produce any missing protein. Yet not all mRNA therapies are equally likely to succeed. Over the past several years, an increasing number of clinical trials with siRNA- and antisense oligonucleotide-based drugs have revealed three key concepts that will likely extend to mRNA therapies delivered by nonviral systems. First, scientists have come to understand that some genes make better targets for RNA therapies than others. Second, scientists have learned that the type and position of chemical modifications made to an RNA drug can alter its therapeutic window, toxicity, and bioavailability. Third, scientists have found that safe and targeted drug delivery vehicles are required to ferry mRNA therapies into diseased cells. In this study, we apply these learnings to cystic fibrosis (CF). We also describe lessons learned from a subset of CF gene therapies that have already been tested in patients. Finally, we highlight the scientific advances that are still required for nonviral mRNA- or CRISPR-based drugs to treat CF successfully in patients.
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Affiliation(s)
- Alejandro Da Silva Sanchez
- Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Kalina Paunovska
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Ana Cristian
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - James E. Dahlman
- Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
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16
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Phuan PW, Haggie PM, Tan JA, Rivera AA, Finkbeiner WE, Nielson DW, Thomas MM, Janahi IA, Verkman AS. CFTR modulator therapy for cystic fibrosis caused by the rare c.3700A>G mutation. J Cyst Fibros 2020; 20:452-459. [PMID: 32674984 DOI: 10.1016/j.jcf.2020.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/09/2020] [Accepted: 07/06/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND The c.3700A>G mutation, a rare cystic fibrosis (CF)-causing CFTR mutation found mainly in the Middle East, produces full-length transcript encoding a missense mutation (I1234V-CFTR), and a cryptic splice site that deletes 6 amino acids in nucleotide binding domain 2 (I1234del-CFTR). METHODS FRT cell models expressing I1234V-CFTR and I1234del-CFTR were generated. We also studied an I1234del-CFTR-expressing gene-edited human bronchial (16HBE14o-) cell model, and primary cultures of nasal epithelial cells from a c.3700A>G homozygous subject. To identify improved mutation-specific CFTR modulators, high-throughput screening was done using I1234del-CFTR-expressing FRT cells. Motivated by the in vitro findings, Trikafta was tested in two c.3700A>G homozygous CF subjects. RESULTS FRT cells expressing full-length I1234V-CFTR had similar function to that of wildtype CFTR. I1234del-CFTR showed reduced activity, with modest activation seen with potentiators VX-770 and GLPG1837, correctors VX-809, VX-661 and VX-445, and low-temperature incubation. Screening identified novel arylsulfonyl-piperazine and spiropiperidine-quinazolinone correctors, which when used in combination with VX-445 increased current ~2-fold compared with the VX-661/VX-445 combination. The combination of VX-770 with arylsulfonamide-pyrrolopyridine, piperidine-pyridoindole or pyrazolo-quinoline potentiators gave 2-4-fold greater current than VX-770 alone. Combination potentiator (co-potentiator) efficacy was also seen in gene-edited I1234del-CFTR-expressing human bronchial epithelial cells. In two CF subjects homozygous for the c.3700A>G mutation, one subject had a 27 mmol/L decrease in sweat chloride and symptomatic improvement on Trikafta, and a second subject showed a small improvement in lung function. CONCLUSIONS These results support the potential benefit of CFTR modulators, including co-potentiators, for CF caused by the c.3700A>G mutation.
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Affiliation(s)
- Puay-Wah Phuan
- Department of Medicine, University of California San Francisco, CA 94143, USA
| | - Peter M Haggie
- Department of Medicine, University of California San Francisco, CA 94143, USA.
| | - Joseph A Tan
- Department of Medicine, University of California San Francisco, CA 94143, USA
| | - Amber A Rivera
- Department of Medicine, University of California San Francisco, CA 94143, USA
| | - Walter E Finkbeiner
- Department of Pathology, University of California San Francisco, CA 94143, USA
| | - Dennis W Nielson
- Department of Pediatrics, University of California San Francisco, CA 94143, USA
| | - Merlin M Thomas
- Department of Chest, Hamad General Hospital, PO Box 3050, Doha, Qatar
| | - Ibrahim A Janahi
- Pediatric Pulmonary, Pediatric Medicine, Sidra Medicine, PO Box 26999, Doha, Qatar
| | - Alan S Verkman
- Department of Medicine, University of California San Francisco, CA 94143, USA; Department of Physiology, University of California San Francisco, CA 94143, USA
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Abstract
PURPOSE OF REVIEW Cystic fibrosis transmembrane conductance receptor (CFTR) modulators are a new class of drugs that treat the underlying cause of cystic fibrosis. To date, there are four approved medications, which are mutation-specific. Although the number of mutations that respond to these agents is expanding, effective CFTR modulators are not available to all cystic fibrosis patients. The purpose of this article is to review the approved CFTR modulators and discuss the mutations that can be treated with these agents, as well as, review the long-term benefits of modulator therapy. RECENT FINDINGS More people with cystic fibrosis can be effectively treated with CFTR modulators. The new, highly effective triple therapy, elexacaftor/tezacaftor/ivacaftor is indicated for more than 90% of patients with cystic fibrosis and ivacaftor is now approved for children as young as 6 months of age with 1 of 30 CFTR mutations. Long-term use of modulator therapy is associated with fewer pulmonary exacerbations, maintenance of lung function, improved weight gain, and quality of life. SUMMARY CFTR modulators are the first therapies developed to treat the underlying defect in cystic fibrosis. Their use is associated with preserved lung function and improved health in patients with cystic fibrosis.
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18
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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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19
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TMEM16A: An Alternative Approach to Restoring Airway Anion Secretion in Cystic Fibrosis? Int J Mol Sci 2020; 21:ijms21072386. [PMID: 32235608 PMCID: PMC7177896 DOI: 10.3390/ijms21072386] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 12/18/2022] Open
Abstract
The concept that increasing airway hydration leads to improvements in mucus clearance and lung function in cystic fibrosis has been clinically validated with osmotic agents such as hypertonic saline and more convincingly with cystic fibrosis transmembrane conductance regulator (CFTR) repair therapies. Although rapidly becoming the standard of care in cystic fibrosis (CF), current CFTR modulators do not treat all patients nor do they restore the rate of decline in lung function to normal levels. As such, novel approaches are still required to ensure all with CF have effective therapies. Although CFTR plays a fundamental role in the regulation of fluid secretion across the airway mucosa, there are other ion channels and transporters that represent viable targets for future therapeutics. In this review article we will summarise the current progress with CFTR-independent approaches to restoring mucosal hydration, including epithelial sodium channel (ENaC) blockade and modulators of SLC26A9. A particular emphasis is given to modulation of the airway epithelial calcium-activated chloride channel (CaCC), TMEM16A, as there is controversy regarding whether it should be positively or negatively modulated. This is discussed in light of a recent report describing for the first time bona fide TMEM16A potentiators and their positive effects upon epithelial fluid secretion and mucus clearance.
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20
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Callebaut I, Mense M, Farinha CM. Exploring the basic mechanisms in Cystic Fibrosis: Promoting data presentation and discussion at the 16th ECFS Basic Science Conference. J Cyst Fibros 2020; 19 Suppl 1:S1-S4. [PMID: 31932104 DOI: 10.1016/j.jcf.2019.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The revolution in cystic fibrosis treatment is rooted in tremendous interdisciplinary research efforts, which led in recent years to significant progress in precision medicine. Since 2004, a key annual event for the CF research community is the ECFS Basic Science Conference (BSC), which is an ideal venue for deep discussions around topical subjects and fosters basic CF-related research in Europe and beyond. This special issue explores topics that were featured at the 16th ECFS BSC, held in Dubrovnik in March 2019 and provides an overview of recent progress in various fields for understanding disease mechanisms, developing relevant cell and animal models and designing breakthrough therapies. The special issue also identifies a number of the key issues and challenges in the future development of transformative therapies for all patients with CF.
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Affiliation(s)
- Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France.
| | - Martin Mense
- Cystic Fibrosis Foundation, CFFT Lab, 44 Hartwell Ave., Lexington, MA 02421, USA
| | - Carlos M Farinha
- Biosystems and Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande 1749-016, Lisboa, Portugal
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21
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Regulation of CFTR Biogenesis by the Proteostatic Network and Pharmacological Modulators. Int J Mol Sci 2020; 21:ijms21020452. [PMID: 31936842 PMCID: PMC7013518 DOI: 10.3390/ijms21020452] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 12/14/2022] Open
Abstract
Cystic fibrosis (CF) is the most common lethal inherited disease among Caucasians in North America and a significant portion of Europe. The disease arises from one of many mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator, or CFTR. The most common disease-associated allele, F508del, along with several other mutations affect the folding, transport, and stability of CFTR as it transits from the endoplasmic reticulum (ER) to the plasma membrane, where it functions primarily as a chloride channel. Early data demonstrated that F508del CFTR is selected for ER associated degradation (ERAD), a pathway in which misfolded proteins are recognized by ER-associated molecular chaperones, ubiquitinated, and delivered to the proteasome for degradation. Later studies showed that F508del CFTR that is rescued from ERAD and folds can alternatively be selected for enhanced endocytosis and lysosomal degradation. A number of other disease-causing mutations in CFTR also undergo these events. Fortunately, pharmacological modulators of CFTR biogenesis can repair CFTR, permitting its folding, escape from ERAD, and function at the cell surface. In this article, we review the many cellular checkpoints that monitor CFTR biogenesis, discuss the emergence of effective treatments for CF, and highlight future areas of research on the proteostatic control of CFTR.
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Targeting cell plasticity for regeneration: From in vitro to in vivo reprogramming. Adv Drug Deliv Rev 2020; 161-162:124-144. [PMID: 32822682 DOI: 10.1016/j.addr.2020.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 12/14/2022]
Abstract
The discovery of induced pluripotent stem cells (iPSCs), reprogrammed to pluripotency from somatic cells, has transformed the landscape of regenerative medicine, disease modelling and drug discovery pipelines. Since the first generation of iPSCs in 2006, there has been enormous effort to develop new methods that increase reprogramming efficiency, and obviate the need for viral vectors. In parallel to this, the promise of in vivo reprogramming to convert cells into a desired cell type to repair damage in the body, constitutes a new paradigm in approaches for tissue regeneration. This review article explores the current state of reprogramming techniques for iPSC generation with a specific focus on alternative methods that use biophysical and biochemical stimuli to reduce or eliminate exogenous factors, thereby overcoming the epigenetic barrier towards vector-free approaches with improved clinical viability. We then focus on application of iPSC for therapeutic approaches, by giving an overview of ongoing clinical trials using iPSCs for a variety of health conditions and discuss future scope for using materials and reagents to reprogram cells in the body.
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