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Luo S, Rollins S, Schmitz-Abe K, Tam A, Li Q, Shi J, Lin J, Wang R, Agrawal PB. The solute carrier family 26 member 9 modifies rapidly progressing cystic fibrosis associated with homozygous F508del CFTR mutation. Clin Chim Acta 2024; 561:119765. [PMID: 38852790 DOI: 10.1016/j.cca.2024.119765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/14/2024] [Accepted: 06/04/2024] [Indexed: 06/11/2024]
Abstract
BACKGROUND AND AIMS Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations to the CF transmembrane conductance regulator (CFTR). Symptoms and severity of the disease can be quite variable suggesting modifier genes play an important role. MATERIALS AND METHODS Exome sequencing was performed on six individuals carrying homozygous deltaF508 for CFTR genotype but present with rapidly progressing CF (RPCF). Data was analyzed using an unbiased genome-wide genetic burden test against 3076 controls. Single cell RNA sequencing data from LungMAP was utilized to evaluate unique and co-expression of candidate genes, and structural modeling to evaluate the deleterious effects of identified candidate variants. RESULTS We have identified solute carrier family 26 member 9 (SLC26A9) as a modifier gene to be associated with RPCF. Two rare missense SLC26A9 variants were discovered in three of six individuals deemed to have RPCF: c.229G > A; p.G77S (present in two patients), and c.1885C > T; p.P629S. Co-expression of SLC26A9 and CFTR mRNA is limited across different lung cell types, with the highest level of co-expression seen in human (6.3 %) and mouse (9.0 %) alveolar type 2 (AT2) cells. Structural modeling suggests deleterious effects of these mutations as they are in critical protein domains which might affect the anion transport capability of SLC26A9. CONCLUSION The enrichment of rare and potentially deleterious SLC26A9 mutations in patients with RPCF suggests SLC26A9 may act as an alternative anion transporter in CF and is a modifier gene associated with this lung phenotype.
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Affiliation(s)
- Shiyu Luo
- Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine and Holtz Children's Hospital, Jackson Health System, Miami, FL 33136, USA; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Stuart Rollins
- Division of Pulmonary Medicine, Boston Children's Hospital, USA; Department of Medicine, Harvard Medical School, USA
| | - Klaus Schmitz-Abe
- Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine and Holtz Children's Hospital, Jackson Health System, Miami, FL 33136, USA; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Amy Tam
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Qifei Li
- Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine and Holtz Children's Hospital, Jackson Health System, Miami, FL 33136, USA; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Jiahai Shi
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jasmine Lin
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ruobing Wang
- Division of Pulmonary Medicine, Boston Children's Hospital, USA; Department of Medicine, Harvard Medical School, USA; Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02115, USA.
| | - Pankaj B Agrawal
- Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine and Holtz Children's Hospital, Jackson Health System, Miami, FL 33136, USA; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Yuan F, Gasser GN, Lemire E, Montoro DT, Jagadeesh K, Zhang Y, Duan Y, Ievlev V, Wells KL, Rotti PG, Shahin W, Winter M, Rosen BH, Evans I, Cai Q, Yu M, Walsh SA, Acevedo MR, Pandya DN, Akurathi V, Dick DW, Wadas TJ, Joo NS, Wine JJ, Birket S, Fernandez CM, Leung HM, Tearney GJ, Verkman AS, Haggie PM, Scott K, Bartels D, Meyerholz DK, Rowe SM, Liu X, Yan Z, Haber AL, Sun X, Engelhardt JF. Transgenic ferret models define pulmonary ionocyte diversity and function. Nature 2023; 621:857-867. [PMID: 37730992 PMCID: PMC10533402 DOI: 10.1038/s41586-023-06549-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 08/17/2023] [Indexed: 09/22/2023]
Abstract
Speciation leads to adaptive changes in organ cellular physiology and creates challenges for studying rare cell-type functions that diverge between humans and mice. Rare cystic fibrosis transmembrane conductance regulator (CFTR)-rich pulmonary ionocytes exist throughout the cartilaginous airways of humans1,2, but limited presence and divergent biology in the proximal trachea of mice has prevented the use of traditional transgenic models to elucidate ionocyte functions in the airway. Here we describe the creation and use of conditional genetic ferret models to dissect pulmonary ionocyte biology and function by enabling ionocyte lineage tracing (FOXI1-CreERT2::ROSA-TG), ionocyte ablation (FOXI1-KO) and ionocyte-specific deletion of CFTR (FOXI1-CreERT2::CFTRL/L). By comparing these models with cystic fibrosis ferrets3,4, we demonstrate that ionocytes control airway surface liquid absorption, secretion, pH and mucus viscosity-leading to reduced airway surface liquid volume and impaired mucociliary clearance in cystic fibrosis, FOXI1-KO and FOXI1-CreERT2::CFTRL/L ferrets. These processes are regulated by CFTR-dependent ionocyte transport of Cl- and HCO3-. Single-cell transcriptomics and in vivo lineage tracing revealed three subtypes of pulmonary ionocytes and a FOXI1-lineage common rare cell progenitor for ionocytes, tuft cells and neuroendocrine cells during airway development. Thus, rare pulmonary ionocytes perform critical CFTR-dependent functions in the proximal airway that are hallmark features of cystic fibrosis airway disease. These studies provide a road map for using conditional genetics in the first non-rodent mammal to address gene function, cell biology and disease processes that have greater evolutionary conservation between humans and ferrets.
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Affiliation(s)
- Feng Yuan
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Grace N Gasser
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Evan Lemire
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | | | | | - Yan Zhang
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Yifan Duan
- Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Vitaly Ievlev
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Kristen L Wells
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Pavana G Rotti
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Weam Shahin
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Michael Winter
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Bradley H Rosen
- Division of Pulmonary, Critical Care, Occupational, and Sleep Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Idil Evans
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Qian Cai
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Miao Yu
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Susan A Walsh
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Michael R Acevedo
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Darpan N Pandya
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Vamsidhar Akurathi
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - David W Dick
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Thaddeus J Wadas
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Nam Soo Joo
- Cystic Fibrosis Research Laboratory, Department of Psychology, Stanford University, Stanford, CA, USA
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Jeffrey J Wine
- Cystic Fibrosis Research Laboratory, Department of Psychology, Stanford University, Stanford, CA, USA
| | - Susan Birket
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Courtney M Fernandez
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hui Min Leung
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
| | - Guillermo J Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
| | - Alan S Verkman
- Department of Medicine, UCSF, San Francisco, CA, USA
- Department of Physiology, UCSF, San Francisco, CA, USA
| | - Peter M Haggie
- Department of Medicine, UCSF, San Francisco, CA, USA
- Department of Physiology, UCSF, San Francisco, CA, USA
| | - Kathleen Scott
- Office of Animal Resources, University of Iowa, Iowa City, IA, USA
| | - Douglas Bartels
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | | | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Xiaoming Liu
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Ziying Yan
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Adam L Haber
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
| | - Xingshen Sun
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
| | - John F Engelhardt
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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Oliver KE, Carlon MS, Pedemonte N, Lopes-Pacheco M. The revolution of personalized pharmacotherapies for cystic fibrosis: what does the future hold? Expert Opin Pharmacother 2023; 24:1545-1565. [PMID: 37379072 PMCID: PMC10528905 DOI: 10.1080/14656566.2023.2230129] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/16/2023] [Accepted: 06/23/2023] [Indexed: 06/29/2023]
Abstract
INTRODUCTION Cystic fibrosis (CF), a potentially fatal genetic disease, is caused by loss-of-function mutations in the gene encoding for the CFTR chloride/bicarbonate channel. Modulator drugs rescuing mutant CFTR traffic and function are now in the clinic, providing unprecedented breakthrough therapies for people with CF (PwCF) carrying specific genotypes. However, several CFTR variants are unresponsive to these therapies. AREA COVERED We discussed several therapeutic approaches that are under development to tackle the fundamental cause of CF, including strategies targeting defective CFTR mRNA and/or protein expression and function. Alternatively, defective chloride secretion and dehydration in CF epithelia could be restored by exploiting pharmacological modulation of alternative targets, i.e., ion channels/transporters that concur with CFTR to maintain the airway surface liquid homeostasis (e.g., ENaC, TMEM16A, SLC26A4, SLC26A9, and ATP12A). Finally, we assessed progress and challenges in the development of gene-based therapies to replace or correct the mutant CFTR gene. EXPERT OPINION CFTR modulators are benefiting many PwCF responsive to these drugs, yielding substantial improvements in various clinical outcomes. Meanwhile, the CF therapy development pipeline continues to expand with the development of novel CFTR modulators and alternative therapeutic strategies with the ultimate goal of providing effective therapies for all PwCF in the foreseeable future.
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Affiliation(s)
- Kathryn E. Oliver
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
- Center for Cystic Fibrosis and Airways Disease Research, Emory University and Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Marianne S. Carlon
- Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
- Center for Molecular Medicine, KU Leuven, Leuven, Belgium
| | | | - Miquéias Lopes-Pacheco
- Biosystems & Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisbon, Lisbon, Portugal
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Gavioli Santos L, Villa-Nova Pereira S, Henrique Pezzo Kmit A, Cardoso Bonadia L, Silvia Bertuzzo C, Dirceu Ribeiro J, Nitsch Mazzola T, Augusto Lima Marson F. Identification of Single Nucleotide Variants in SLC26A9 Gene in Patients with Cystic Fibrosis (p.Phe508del Homozygous) and its Association to Orkambi® (Lumacaftor and Ivacaftor) Response in vitro. Gene 2023; 871:147428. [PMID: 37068695 DOI: 10.1016/j.gene.2023.147428] [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: 02/04/2023] [Revised: 03/28/2023] [Accepted: 04/10/2023] [Indexed: 04/19/2023]
Abstract
BACKGROUND Since patients with cystic fibrosis with different Cystic Fibrosis Transmembrane Regulator (CFTR) genotypes present a wide response variability for modulator drugs such as Orkambi®, it is important to screen variants in candidate genes with an impact on precision and personalized medicine, such as Solute Carrier Family 26, member 9 (SLC26A9) gene. METHODS Sanger sequencing for the exons and intron-exon boundary junctions of the SLC26A9 gene was employed in nine individuals with p.Phe508del homozygous genotype for the CFTR gene who were not under CFTR modulators therapy. The sequencing variants were evaluated by in silico prediction tools. The CFTR function was measured by cAMP-stimulated current (ΔIsc-eq-FSK) in polarized CFTR of human nasal epithelial cells cultured in micro-Ussing chambers with Orkambi®. RESULTS We found 24 intronic variants, three in the coding region (missense variants - rs74146719 and rs16856462 and synonymous - rs33943971), and three in the three prime untranslated region (3' UTR) region in the SLC26A9 gene. Twenty variants were considered benign according to American College of Medical Genetics and Genomics guidelines, and ten were classified as uncertain significance. Although some variants had deleterious predictions or possible alterations in splicing, the majority of predictions were benign or neutral. When we analyzed the ΔIsc-eq-FSK response to Orkambi®, there were no significant differences within the genotypes and alleles for all 30 variants in the SLC26A9 gene. CONCLUSIONS Among the nine individuals with p.Phe508del homozygous genotype for the CFTR gene, no pathogenic SLC26A9 variants were found, and we did not detect associations from the 30 SLC26A9 variants and the response to the Orkambi® in vitro.
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Affiliation(s)
- Luana Gavioli Santos
- Laboratory of Medical Genetics and Genome Medicine, Department of Medical Genetics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil.
| | - Stéphanie Villa-Nova Pereira
- Laboratory of Medical Genetics and Genome Medicine, Department of Medical Genetics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil.
| | - Arthur Henrique Pezzo Kmit
- Center for Investigation in Pediatrics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil.
| | - Luciana Cardoso Bonadia
- Laboratory of Medical Genetics and Genome Medicine, Department of Medical Genetics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil.
| | - Carmem Silvia Bertuzzo
- Laboratory of Medical Genetics and Genome Medicine, Department of Medical Genetics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil.
| | - José Dirceu Ribeiro
- Center for Investigation in Pediatrics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil.
| | - Taís Nitsch Mazzola
- Center for Investigation in Pediatrics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil.
| | - Fernando Augusto Lima Marson
- Laboratory of Medical Genetics and Genome Medicine, Department of Medical Genetics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil; Center for Investigation in Pediatrics, Faculty of Medical Sciences, University of Campinas, Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, Campinas 13083-887, São Paulo, Brazil; Laboratory of Human and Medical Genetics, Laboratory of Cell and Molecular Tumor Biology and Bioactive Compounds, São Francisco University, Avenida São Francisco de Assis, 218, Jardim São José, Bragança Paulista 12916-900, São Paulo, Brazil.
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Mésinèle J, Ruffin M, Guillot L, Corvol H. Modifier Factors of Cystic Fibrosis Phenotypes: A Focus on Modifier Genes. Int J Mol Sci 2022; 23:ijms232214205. [PMID: 36430680 PMCID: PMC9698440 DOI: 10.3390/ijms232214205] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/07/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
Although cystic fibrosis (CF) is recognized as a monogenic disease, due to variants within the CFTR (Cystic Fibrosis Transmembrane Regulator) gene, an extreme clinical heterogeneity is described among people with CF (pwCF). Apart from the exocrine pancreatic status, most studies agree that there is little association between CFTR variants and disease phenotypes. Environmental factors have been shown to contribute to this heterogeneity, accounting for almost 50% of the variability of the lung function of pwCF. Nevertheless, pwCF with similar CFTR variants and sharing the same environment (such as in siblings) may have highly variable clinical manifestations not explained by CFTR variants, and only partly explained by environmental factors. It is recognized that genetic variants located outside the CFTR locus, named "modifier genes", influence the clinical expression of the disease. This short review discusses the latest studies that have described modifier factors associated with the various CF phenotypes as well as the response to the recent CFTR modulator therapies.
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Affiliation(s)
- Julie Mésinèle
- Sorbonne Université, Inserm U938, Centre de Recherche Saint-Antoine (CRSA), 75012 Paris, France
- Inovarion, 75005 Paris, France
| | - Manon Ruffin
- Sorbonne Université, Inserm U938, Centre de Recherche Saint-Antoine (CRSA), 75012 Paris, France
| | - Loïc Guillot
- Sorbonne Université, Inserm U938, Centre de Recherche Saint-Antoine (CRSA), 75012 Paris, France
- Correspondence: (L.G.); (H.C.)
| | - Harriet Corvol
- Sorbonne Université, Inserm U938, Centre de Recherche Saint-Antoine (CRSA), 75012 Paris, France
- Sorbonne Université, Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Trousseau, Service de Pneumologie Pédiatrique, 75012 Paris, France
- Correspondence: (L.G.); (H.C.)
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Gong J, He G, Wang C, Bartlett C, Panjwani N, Mastromatteo S, Lin F, Keenan K, Avolio J, Halevy A, Shaw M, Esmaeili M, Côté-Maurais G, Adam D, Bégin S, Bjornson C, Chilvers M, Reisman J, Price A, Parkins M, van Wylick R, Berthiaume Y, Bilodeau L, Mateos-Corral D, Hughes D, Smith MJ, Morrison N, Brusky J, Tullis E, Stephenson AL, Quon BS, Wilcox P, Leung WM, Solomon M, Sun L, Brochiero E, Moraes TJ, Gonska T, Ratjen F, Rommens JM, Strug LJ. Genetic evidence supports the development of SLC26A9 targeting therapies for the treatment of lung disease. NPJ Genom Med 2022; 7:28. [PMID: 35396391 PMCID: PMC8993824 DOI: 10.1038/s41525-022-00299-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/04/2022] [Indexed: 12/19/2022] Open
Abstract
Over 400 variants in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) are CF-causing. CFTR modulators target variants to improve lung function, but marked variability in response exists and current therapies do not address all CF-causing variants highlighting unmet needs. Alternative epithelial ion channel/transporters such as SLC26A9 could compensate for CFTR dysfunction, providing therapeutic targets that may benefit all individuals with CF. We investigate the relationship between rs7512462, a marker of SLC26A9 activity, and lung function pre- and post-treatment with CFTR modulators in Canadian and US CF cohorts, in the general population, and in those with chronic obstructive pulmonary disease (COPD). Rs7512462 CC genotype is associated with greater lung function in CF individuals with minimal function variants (for which there are currently no approved therapies; p = 0.008); and for gating (p = 0.033) and p.Phe508del/ p.Phe508del (p = 0.006) genotypes upon treatment with CFTR modulators. In parallel, human nasal epithelia with CC and p.Phe508del/p.Phe508del after Ussing chamber analysis of a combination of approved and experimental modulator treatments show greater CFTR function (p = 0.0022). Beyond CF, rs7512462 is associated with peak expiratory flow in a meta-analysis of the UK Biobank and Spirometa Consortium (p = 2.74 × 10-44) and provides p = 0.0891 in an analysis of COPD case-control status in the UK Biobank defined by spirometry. These findings support SLC26A9 as a therapeutic target to improve lung function for all people with CF and in individuals with other obstructive lung diseases.
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Affiliation(s)
- Jiafen Gong
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Gengming He
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Biostatistics Division, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Cheng Wang
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Claire Bartlett
- Program in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Naim Panjwani
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Scott Mastromatteo
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Fan Lin
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Katherine Keenan
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Program in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Julie Avolio
- Program in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Anat Halevy
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Michelle Shaw
- Program in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Mohsen Esmaeili
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Guillaume Côté-Maurais
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Damien Adam
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Stéphanie Bégin
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | | | - Mark Chilvers
- British Columbia Children's Hospital, Vancouver, BC, Canada
| | - Joe Reisman
- The Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - April Price
- The Children's Hospital, London Health Science Centre, London, ON, Canada
| | | | | | - Yves Berthiaume
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Lara Bilodeau
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec City, QC, Canada
| | | | | | - Mary J Smith
- Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Nancy Morrison
- Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada
| | - Janna Brusky
- Department of Pediatrics, University of Saskatchewan, Saskatoon, SK, Canada
| | | | | | | | | | | | - Melinda Solomon
- Respiratory Medicine, Hospital for Sick Children, Toronto, ON, Canada
- Department of Paediatrics, University of Toronto, Toronto, ON, Canada
| | - Lei Sun
- Biostatistics Division, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- Department of Statistical Sciences, University of Toronto, Toronto, ON, Canada
| | - Emmanuelle Brochiero
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Theo J Moraes
- Program in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Respiratory Medicine, Hospital for Sick Children, Toronto, ON, Canada
| | - Tanja Gonska
- Program in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Division of Gastroenterology, Hepatology and Nutrition, The Hospital for Sick Children, Toronto, ON, Canada
| | - Felix Ratjen
- Program in Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Paediatrics, University of Toronto, Toronto, ON, Canada
| | - Johanna M Rommens
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Lisa J Strug
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada.
- Biostatistics Division, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
- Department of Statistical Sciences, University of Toronto, Toronto, ON, Canada.
- The Centre for Applied Genomics, Hospital for Sick Children, Toronto, ON, Canada.
- Department of Computer Science, University of Toronto, Toronto, ON, Canada.
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Factors Predisposing the Response to Lumacaftor/Ivacaftor in People with Cystic Fibrosis. J Pers Med 2022; 12:jpm12020252. [PMID: 35207740 PMCID: PMC8876860 DOI: 10.3390/jpm12020252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 12/04/2022] Open
Abstract
Lumacaftor/ivacaftor (LUMA-IVA) therapy is prescribed to people with cystic fibrosis (pwCF) homozygous for the Phe508del-CFTR variant to restore CFTR protein function. There is, however, large inter-individual variability in treatment response. Here, we seek to identify clinical and/or genetic factors that may modulate the response to this CFTR modulator therapy. A total of 765 pwCF older than 12 years under LUMA-IVA therapy and with lung function and nutritional measurements available before and after treatment initiation were included. Response to treatment was determined by the change in lung function and nutritional status, from baseline and over the first two years after initiation, and it was assessed by weighted generalized estimating equation models. Gains in lung function and nutritional status were observed after 6 months of treatment (on average 2.11 ± 7.81% for percent predicted FEV1 and 0.44 ± 0.77 kg/m2 for BMI) and sustained over the 2 years. We observed that the more severe patients gained the most in lung function and nutritional status. While females started with a nutritional status more impaired than males, they had a larger response and regained BMI Z-score values similar to men after 2 years of treatment. We observed no association between variants in solute carrier (SLC) genes and the respiratory function response to LUMA-IVA, but the SLC6A14 rs12839137 variant was associated with the nutritional response. Further investigations, including other genomic regions, will be needed to fully explore the inter-individual variability of the response to LUMA-IVA.
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8
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SLC26A9 as a Potential Modifier and Therapeutic Target in Cystic Fibrosis Lung Disease. Biomolecules 2022; 12:biom12020202. [PMID: 35204703 PMCID: PMC8961553 DOI: 10.3390/biom12020202] [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: 12/27/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 11/16/2022] Open
Abstract
SLC26A9 belongs to the solute carrier family 26 (SLC26), which comprises membrane proteins involved in ion transport mechanisms. On the basis of different preliminary findings, including the phenotype of SlC26A9-deficient mice and its possible role as a gene modifier of the human phenotype and treatment response, SLC26A9 has emerged as one of the most interesting alternative targets for the treatment of cystic fibrosis (CF). However, despite relevant clues, some open issues and controversies remain. The lack of specific pharmacological modulators, the elusive expression reported in the airways, and its complex relationships with CFTR and the CF phenotype prevent us from conclusively understanding the contribution of SLC26A9 in human lung physiology and its real potential as a therapeutic target in CF. In this review, we summarized the various studies dealing with SLC26A9 expression, molecular structure, and function as an anion channel or transporter; its interaction and functional relationships with CFTR; and its role as a gene modifier and tried to reconcile them in order to highlight the current understanding and the gap in knowledge regarding the contribution of SLC26A9 to human lung physiology and CF disease and treatment.
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9
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Thursfield RM, Shafi N, Davies JC. COUNTERPOINT: In the Era of Cystic Fibrosis Transmembrane Regulator Protein Modulator Therapy, Are the Treatment Goals for Adults Now Different From Those for Children With Cystic Fibrosis? No. Chest 2022; 161:21-24. [DOI: 10.1016/j.chest.2021.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/31/2021] [Accepted: 06/14/2021] [Indexed: 10/19/2022] Open
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10
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SLC26A9 is selected for endoplasmic reticulum associated degradation (ERAD) via Hsp70-dependent targeting of the soluble STAS domain. Biochem J 2021; 478:4203-4220. [PMID: 34821356 PMCID: PMC8826537 DOI: 10.1042/bcj20210644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 12/24/2022]
Abstract
SLC26A9, a member of the solute carrier protein family, transports chloride ions across various epithelia. SLC26A9 also associates with other ion channels and transporters linked to human health, and in some cases these heterotypic interactions are essential to support the biogenesis of both proteins. Therefore, understanding how this complex membrane protein is initially folded might provide new therapeutic strategies to overcome deficits in the function of SLC26A9 partners, one of which is associated with Cystic Fibrosis. To this end, we developed a novel yeast expression system for SLC26A9. This facile system has been used extensively with other ion channels and transporters to screen for factors that oversee protein folding checkpoints. As commonly observed for other channels and transporters, we first noted that a substantial fraction of SLC26A9 is targeted for endoplasmic reticulum associated degradation (ERAD), which destroys folding-compromised proteins in the early secretory pathway. We next discovered that ERAD selection requires the Hsp70 chaperone, which can play a vital role in ERAD substrate selection. We then created SLC26A9 mutants and found that the transmembrane-rich domain of SLC26A9 was quite stable, whereas the soluble cytosolic STAS domain was responsible for Hsp70-dependent ERAD. To support data obtained in the yeast model, we were able to recapitulate Hsp70-facilitated ERAD of the STAS domain in human tissue culture cells. These results indicate that a critical barrier to nascent membrane protein folding can reside within a specific soluble domain, one that is monitored by components associated with the ERAD machinery.
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11
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Butnariu LI, Țarcă E, Cojocaru E, Rusu C, Moisă ȘM, Leon Constantin MM, Gorduza EV, Trandafir LM. Genetic Modifying Factors of Cystic Fibrosis Phenotype: A Challenge for Modern Medicine. J Clin Med 2021; 10:5821. [PMID: 34945117 PMCID: PMC8707808 DOI: 10.3390/jcm10245821] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 12/13/2022] Open
Abstract
Cystic fibrosis (CF) is a monogenic autosomal recessive disease caused by cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. CF is characterized by a high phenotypic variability present even in patients with the same genotype. This is due to the intervention of modifier genes that interact with both the CFTR gene and environmental factors. The purpose of this review is to highlight the role of non-CFTR genetic factors (modifier genes) that contribute to phenotypic variability in CF. We analyzed literature data starting with candidate gene studies and continuing with extensive studies, such as genome-wide association studies (GWAS) and whole exome sequencing (WES). The results of both types of studies revealed that the number of modifier genes in CF patients is impressive. Their identification offers a new perspective on the pathophysiological mechanisms of the disease, paving the way for the understanding of other genetic disorders. In conclusion, in the future, genetic analysis, such as GWAS and WES, should be performed routinely. A challenge for future research is to integrate their results in the process of developing new classes of drugs, with a goal to improve the prognosis, increase life expectancy, and enhance quality of life among CF patients.
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Affiliation(s)
- Lăcrămioara Ionela Butnariu
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (L.I.B.); (C.R.); (E.V.G.)
| | - Elena Țarcă
- Department of Surgery II—Pediatric Surgery, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iaşi, Romania
| | - Elena Cojocaru
- Department of Morphofunctional Sciences I, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iaşi, Romania
| | - Cristina Rusu
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (L.I.B.); (C.R.); (E.V.G.)
| | - Ștefana Maria Moisă
- Department of Mother and Child, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (Ș.M.M.); (L.M.T.)
| | | | - Eusebiu Vlad Gorduza
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (L.I.B.); (C.R.); (E.V.G.)
| | - Laura Mihaela Trandafir
- Department of Mother and Child, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (Ș.M.M.); (L.M.T.)
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12
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Synergy in Cystic Fibrosis Therapies: Targeting SLC26A9. Int J Mol Sci 2021; 22:ijms222313064. [PMID: 34884866 PMCID: PMC8658147 DOI: 10.3390/ijms222313064] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/24/2021] [Accepted: 12/01/2021] [Indexed: 11/16/2022] Open
Abstract
SLC26A9, a constitutively active Cl- transporter, has gained interest over the past years as a relevant disease modifier in several respiratory disorders including Cystic Fibrosis (CF), asthma, and non-CF bronchiectasis. SLC26A9 contributes to epithelial Cl- secretion, thus preventing mucus obstruction under inflammatory conditions. Additionally, SLC26A9 was identified as a CF gene modifier, and its polymorphisms were shown to correlate with the response to drugs modulating CFTR, the defective protein in CF. Here, we aimed to investigate the relationship between SLC26A9 and CFTR, and its role in CF pathogenesis. Our data show that SLC26A9 expression contributes to enhanced CFTR expression and function. While knocking-down SLC26A9 in human bronchial cells leads to lower wt- and F508del-CFTR expression, function, and response to CFTR correctors, the opposite occurs upon its overexpression, highlighting SLC26A9 relevance for CF. Accordingly, F508del-CFTR rescue by the most efficient correctors available is further enhanced by increasing SLC26A9 expression. Interestingly, SLC26A9 overexpression does not increase the PM expression of non-F508del CFTR traffic mutants, namely those unresponsive to corrector drugs. Altogether, our data indicate that SLC26A9 stabilizes CFTR at the ER level and that the efficacy of CFTR modulator drugs may be further enhanced by increasing its expression.
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13
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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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14
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Lee JA, Cho A, Huang EN, Xu Y, Quach H, Hu J, Wong AP. Gene therapy for cystic fibrosis: new tools for precision medicine. J Transl Med 2021; 19:452. [PMID: 34717671 PMCID: PMC8556969 DOI: 10.1186/s12967-021-03099-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/01/2021] [Indexed: 12/18/2022] Open
Abstract
The discovery of the Cystic fibrosis (CF) gene in 1989 has paved the way for incredible progress in treating the disease such that the mean survival age of individuals living with CF is now ~58 years in Canada. Recent developments in gene targeting tools and new cell and animal models have re-ignited the search for a permanent genetic cure for all CF. In this review, we highlight some of the more recent gene therapy approaches as well as new models that will provide insight into personalized therapies for CF.
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Affiliation(s)
- Jin-A Lee
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, 686 Bay Street, PGCRL 16-9420, Toronto, ON, M5G0A4, Canada
| | - Alex Cho
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Elena N Huang
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Yiming Xu
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Henry Quach
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Jim Hu
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Program in Translational Medicine, Hospital for Sick Children, Toronto, ON, M5G0A4, Canada
| | - Amy P Wong
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, 686 Bay Street, PGCRL 16-9420, Toronto, ON, M5G0A4, Canada. .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.
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15
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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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16
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Sepahzad A, Morris-Rosendahl DJ, Davies JC. Cystic Fibrosis Lung Disease Modifiers and Their Relevance in the New Era of Precision Medicine. Genes (Basel) 2021; 12:genes12040562. [PMID: 33924524 PMCID: PMC8069009 DOI: 10.3390/genes12040562] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/08/2021] [Accepted: 04/08/2021] [Indexed: 02/06/2023] Open
Abstract
Our understanding of cystic fibrosis (CF) has grown exponentially since the discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 1989. With evolving genetic and genomic tools, we have come to better understand the role of CFTR genotypes in the pathophysiology of the disease. This, in turn, has paved the way for the development of modulator therapies targeted at mutations in the CFTR, which are arguably one of the greatest advances in the treatment of CF. These modulator therapies, however, do not target all the mutations in CFTR that are seen in patients with CF and, furthermore, a variation in response is seen in patients with the same genotype who are taking modulator therapies. There is growing evidence to support the role of non-CFTR modifiers, both genetic and environmental, in determining the variation seen in CF morbidity and mortality and also in the response to existing therapies. This review focusses on key findings from studies using candidate gene and genome-wide approaches to identify CF modifier genes of lung disease in cystic fibrosis and considers the interaction between modifiers and the response to modulator therapies. As the use of modulator therapies expands and we gain data around outcomes, it will be of great interest to investigate this interaction further. Going forward, it will also be crucial to better understand the relative influence of genomic versus environmental factors. With this understanding, we can truly begin to deliver personalised care by better profiling the likely disease phenotype for each patient and their response to treatment.
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Affiliation(s)
- Afsoon Sepahzad
- Department of Paediatric Respiratory Medicine, Royal Brompton and Harefield Hospitals, London SW3 6NP, UK;
| | | | - Jane C. Davies
- Department of Paediatric Respiratory Medicine, Royal Brompton and Harefield Hospitals, London SW3 6NP, UK;
- National Heart & Lung Institute, Imperial College London, Emmanuel Kay Building, 1b Manresa Rd, London SW3 6LR, UK
- Correspondence:
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17
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Duckers J, Lesher B, Thorat T, Lucas E, McGarry LJ, Chandarana K, De Iorio F. Real-World Outcomes of Ivacaftor Treatment in People with Cystic Fibrosis: A Systematic Review. J Clin Med 2021; 10:1527. [PMID: 33917386 PMCID: PMC8038673 DOI: 10.3390/jcm10071527] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 12/20/2022] Open
Abstract
Cystic fibrosis (CF) is a rare, progressive, multi-organ genetic disease. Ivacaftor, a small-molecule CF transmembrane conductance regulator modulator, was the first medication to treat the underlying cause of CF. Since its approval, real-world clinical experience on the use of ivacaftor has been documented in large registries and smaller studies. Here, we systematically review data from real-world observational studies of ivacaftor treatment in people with CF (pwCF). Searches of MEDLINE and Embase identified 368 publications reporting real-world studies that enrolled six or more pwCF treated with ivacaftor published between January 2012 and September 2019. Overall, 75 publications providing data from 57 unique studies met inclusion criteria and were reviewed. Studies reporting within-group change for pwCF treated with ivacaftor consistently showed improvements in lung function, nutritional parameters, and patient-reported respiratory and sino-nasal symptoms. Benefits were evident as early as 1 month following ivacaftor initiation and were sustained over long-term follow-up. Decreases in pulmonary exacerbations, Pseudomonas aeruginosa prevalence, and healthcare resource utilization also were reported for up to 66 months following ivacaftor initiation. In studies comparing ivacaftor treatment to modulator untreated comparator groups, clinical benefits similarly were reported as were decreases in mortality, organ-transplantation, and CF-related complications. The safety profile of ivacaftor observed in these real-world studies was consistent with the well-established safety profile based on clinical trial data. Our systematic review of real-world studies shows ivacaftor treatment in pwCF results in highly consistent and sustained clinical benefit in both pulmonary and non-pulmonary outcomes across various geographies, study designs, patient characteristics, and follow-up durations, confirming and expanding upon evidence from clinical trials.
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Affiliation(s)
- Jamie Duckers
- All Wales Adult Cystic Fibrosis Centre, University Hospital Llandough, Cardiff CF64 2XX, UK
| | - Beth Lesher
- Pharmerit—An OPEN Health Company, 4350 East-West Highway, Suite 1100, Bethesda, MD 20814, USA; (B.L.); (E.L.)
| | - Teja Thorat
- Vertex Pharmaceuticals Incorporated, Boston, MA 02210, USA; (T.T.); (L.J.M.); (K.C.)
| | - Eleanor Lucas
- Pharmerit—An OPEN Health Company, 4350 East-West Highway, Suite 1100, Bethesda, MD 20814, USA; (B.L.); (E.L.)
| | - Lisa J. McGarry
- Vertex Pharmaceuticals Incorporated, Boston, MA 02210, USA; (T.T.); (L.J.M.); (K.C.)
| | - Keval Chandarana
- Vertex Pharmaceuticals Incorporated, Boston, MA 02210, USA; (T.T.); (L.J.M.); (K.C.)
| | - Fosca De Iorio
- Vertex Pharmaceuticals (Europe) Limited, London W2 6BD, UK;
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18
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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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19
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Abstract
Since the cloning of the CFTR gene 30 years ago, research aiming at understanding how CFTR mutations translate to abnormal synthesis or function of the CFTR protein has opened the way to genomically-guided therapy to improve CFTR function. A CFTR potentiator to enhance CFTR channel function has been approved in 2012 for specific and quite rare mutations. Subsequently, combinations of a corrector to increase CFTR expression at the cell membrane, plus a potentiator, have been approved for patients homozygous for the p.Phe508del mutation. To obtain robust correction of CFTR, new combinations of drugs are being studied. A triple combination associating two correctors and one potentiator is very promising and if data of clinical trials are confirmed, it could be a robust and well tolerated CFTR modulator for patients bearing at least one p.Phe508del mutation. Many other strategies are also in development to make these genomically-guided treatments available to all patients with CF. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.
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Affiliation(s)
- I Fajac
- AP-HP, Hôpital Cochin, Service de Physiologie et Explorations Fonctionnelles, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
| | - E Girodon
- APHP, Centre-Université de Paris, Hôpital Cochin, Laboratoire de Génétique et Biologie Moléculaires, Paris, France
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20
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Abstract
Because CFTR gene studies now represent one of the most frequent genetic analyses routinely performed worldwide, the number of rare CFTR variants identified in various clinical situations, regularly increases. To provide appropriate diagnosis and prognosis to CF patients as well as appropriate genetic counseling to families, the clinical impact and the phenotypic spectrum of variants identified by diagnostic techniques need to be characterized. Three complementary locus specific databases, called CFTR1, CFTR2 and CFTR-France were developed to address these issues. Besides, the growing knowledge of the CF pathophysiology and the technical evolution in molecular biology allowed to identify candidate modifier genes, regulatory loci, epigenetic profiles and trans-regulators that could help to refine genotype-phenotype correlations at the individual level. These different factors may contribute to the large phenotypic variability between patients with CF, even when they carry identical CFTR variants, regarding lung function, meconium ileus susceptibility or the risk for developing CFTR-related diabetes and liver disease. Finally, the availability of new therapies that target the CFTR protein for numbers of CF patients led to the identification of 'good' and 'poor' responders, thus raising questions of pharmacogenetics factors that may influence treatment efficiency as a novel feature of the complexity of CF patients' management. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.
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21
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Rang C, Keating D, Wilson J, Kotsimbos T. Re-imagining cystic fibrosis care: next generation thinking. Eur Respir J 2020; 55:13993003.02443-2019. [PMID: 32139465 DOI: 10.1183/13993003.02443-2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 02/20/2020] [Indexed: 12/26/2022]
Abstract
Cystic fibrosis (CF) is a common multi-system genetically inherited condition, predominately found in individuals of Caucasian decent. Since the identification of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene in 1989, and the subsequent improvement in understanding of CF pathophysiology, significant increases in life-expectancy have followed. Initially this was related to improvements in the management and systems of care for treating the various affected organ systems. These cornerstone treatments are still essential for CF patients born today. However, over the last decade, the major advance has been in therapies that target the resultant genetic defect: the dysfunctional CFTR protein. Small molecule agents that target this dysfunctional protein via a variety of mechanisms have led to lung function improvements, reductions in pulmonary exacerbation rates and increases in weight and quality-of-life indices. As more patients receive these agents earlier and earlier in life, it is likely that general CF care will increasingly pivot around these specific therapies, although it is also likely that effects other than those identified in the initial trials will be discovered and need to be managed. Despite great excitement for modulator therapies, they are unlikely to be suitable or available for all; whether this is due to a lack of availability for specific CFTR mutations, drug-reactions or the health economic set-up in certain countries. Nevertheless, the CF community must be applauded for its ongoing focus on research and development for this life-limiting disease. With time, personalised individualised therapy would ideally be the mainstay of CF care.
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Affiliation(s)
- Catherine Rang
- Cystic Fibrosis Service, Dept of Respiratory Medicine, Alfred Health, Melbourne, Australia
| | - Dominic Keating
- Cystic Fibrosis Service, Dept of Respiratory Medicine, Alfred Health, Melbourne, Australia.,Dept of Medicine, Monash University, Alfred Campus, Melbourne, Australia
| | - John Wilson
- Cystic Fibrosis Service, Dept of Respiratory Medicine, Alfred Health, Melbourne, Australia.,Dept of Medicine, Monash University, Alfred Campus, Melbourne, Australia
| | - Tom Kotsimbos
- Cystic Fibrosis Service, Dept of Respiratory Medicine, Alfred Health, Melbourne, Australia.,Dept of Medicine, Monash University, Alfred Campus, Melbourne, Australia
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22
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Aoyama BC, Mogayzel PJ. Ivacaftor for the treatment of cystic fibrosis in children under six years of age. Expert Rev Respir Med 2020; 14:547-557. [PMID: 32154747 DOI: 10.1080/17476348.2020.1741352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Introduction: Cystic fibrosis (CF) results from aberrant ion transport due to abnormalities or absence of the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride transporter that resides on the apical surface of epithelial cells. A novel class of medications, known as CFTR modulators, specifically target the abnormal protein.Areas covered: Ivacaftor increases the open probability of CFTR located on the cell surface, leading to enhanced chloride transport, and has been shown to improve lung function, weight, and quality of life. We reviewed the sentinel studies that lead to the approval of the use of ivacaftor in people with CF age six months and older with at least one CFTR gene mutation that is responsive to ivacaftor based on clinical trial and/or in vitro data. Children with CF have the greatest potential to benefit from CFTR modulator therapy when it is initiated prior to the development of permanent damage; however, challenges remain regarding use of ivacaftor in the youngest pediatric population.Expert opinion: Ivacaftor is safe and effective CFTR modulator that can be prescribed in children over six months of age with at least one CFTR gene mutation that is responsive to ivacaftor.
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Affiliation(s)
- Brianna C Aoyama
- Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter J Mogayzel
- Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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23
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Paranjapye A, Ruffin M, Harris A, Corvol H. Genetic variation in CFTR and modifier loci may modulate cystic fibrosis disease severity. J Cyst Fibros 2020; 19 Suppl 1:S10-S14. [PMID: 31734115 PMCID: PMC7036019 DOI: 10.1016/j.jcf.2019.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 12/11/2022]
Abstract
In patients with cystic fibrosis (CF), genetic variants within and outside the CFTR locus contribute to the variability of the disease severity. CFTR transcription is tightly regulated by cis-regulatory elements (CREs) that control the three-dimensional structure of the locus, chromatin accessibility and transcription factor recruitment. Variants within these CREs may contribute to the pathophysiology and to the phenotypic heterogeneity by altering CFTR transcript abundance. In addition to the CREs, variants outside the CFTR locus, namely "modifiers genes", may also be associated with the clinical variability. This review addresses variants at the CFTR locus itself and CFTR CREs, together with the outcomes of the latest modifier gene studies with respect to the different CF phenotypes.
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Affiliation(s)
- Alekh Paranjapye
- Department of Genetics and Genome Sciences, Case Western Reserve University Medical School, 10900 Euclid Avenue, Cleveland, OH, USA
| | - Manon Ruffin
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, Paris, France
| | - Ann Harris
- Department of Genetics and Genome Sciences, Case Western Reserve University Medical School, 10900 Euclid Avenue, Cleveland, OH, USA.
| | - Harriet Corvol
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, Paris, France; AP-HP, Hôpital Trousseau, Service de Pneumologie Pédiatrique, Paris, France.
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24
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Lopes-Pacheco M. CFTR Modulators: The Changing Face of Cystic Fibrosis in the Era of Precision Medicine. Front Pharmacol 2020; 10:1662. [PMID: 32153386 PMCID: PMC7046560 DOI: 10.3389/fphar.2019.01662] [Citation(s) in RCA: 280] [Impact Index Per Article: 70.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/19/2019] [Indexed: 12/22/2022] Open
Abstract
Cystic fibrosis (CF) is a lethal inherited disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, which result in impairment of CFTR mRNA and protein expression, function, stability or a combination of these. Although CF leads to multifaceted clinical manifestations, the respiratory disorder represents the major cause of morbidity and mortality of these patients. The life expectancy of CF patients has substantially lengthened due to early diagnosis and improvements in symptomatic therapeutic regimens. Quality of life remains nevertheless limited, as these individuals are subjected to considerable clinical, psychosocial and economic burdens. Since the discovery of the CFTR gene in 1989, tremendous efforts have been made to develop therapies acting more upstream on the pathogenesis cascade, thereby overcoming the underlying dysfunctions caused by CFTR mutations. In this line, the advances in cell-based high-throughput screenings have been facilitating the fast-tracking of CFTR modulators. These modulator drugs have the ability to enhance or even restore the functional expression of specific CF-causing mutations, and they have been classified into five main groups depending on their effects on CFTR mutations: potentiators, correctors, stabilizers, read-through agents, and amplifiers. To date, four CFTR modulators have reached the market, and these pharmaceutical therapies are transforming patients' lives with short- and long-term improvements in clinical outcomes. Such breakthroughs have paved the way for the development of novel CFTR modulators, which are currently under experimental and clinical investigations. Furthermore, recent insights into the CFTR structure will be useful for the rational design of next-generation modulator drugs. This review aims to provide a summary of recent developments in CFTR-directed therapeutics. Barriers and future directions are also discussed in order to optimize treatment adherence, identify feasible and sustainable solutions for equitable access to these therapies, and continue to expand the pipeline of novel modulators that may result in effective precision medicine for all individuals with CF.
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Affiliation(s)
- Miquéias Lopes-Pacheco
- Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
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25
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Touré A. Importance of SLC26 Transmembrane Anion Exchangers in Sperm Post-testicular Maturation and Fertilization Potential. Front Cell Dev Biol 2019; 7:230. [PMID: 31681763 PMCID: PMC6813192 DOI: 10.3389/fcell.2019.00230] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/26/2019] [Indexed: 12/17/2022] Open
Abstract
In mammals, sperm cells produced within the testis are structurally differentiated but remain immotile and are unable to fertilize the oocyte unless they undergo a series of maturation events during their transit in the male and female genital tracts. This post-testicular functional maturation is known to rely on the micro-environment of both male and female genital tracts, and is tightly controlled by the pH of their luminal milieus. In particular, within the epididymis, the establishment of a low bicarbonate (HCO3–) concentration contributes to luminal acidification, which is necessary for sperm maturation and subsequent storage in a quiescent state. Following ejaculation, sperm is exposed to the basic pH of the female genital tract and bicarbonate (HCO3–), calcium (Ca2+), and chloride (Cl–) influxes induce biochemical and electrophysiological changes to the sperm cells (cytoplasmic alkalinization, increased cAMP concentration, and protein phosphorylation cascades), which are indispensable for the acquisition of fertilization potential, a process called capacitation. Solute carrier 26 (SLC26) members are conserved membranous proteins that mediate the transport of various anions across the plasma membrane of epithelial cells and constitute important regulators of pH and HCO3– concentration. Most SLC26 members were shown to physically interact and cooperate with the cystic fibrosis transmembrane conductance regulator channel (CFTR) in various epithelia, mainly by stimulating its Cl– channel activity. Among SLC26 members, the function of SLC26A3, A6, and A8 were particularly investigated in the male genital tract and the sperm cells. In this review, we will focus on SLC26s contributions to ionic- and pH-dependent processes during sperm post-testicular maturation. We will specify the current knowledge regarding their functions, based on data from the literature generated by means of in vitro and in vivo studies in knock-out mouse models together with genetic studies of infertile patients. We will also discuss the limits of those studies, the current research gaps and identify some key points for potential developments in this field.
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Affiliation(s)
- Aminata Touré
- INSERM U1016, Centre National de la Recherche Scientifique, UMR 8104, Institut Cochin, Université de Paris, Paris, France
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26
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Shanthikumar S, Neeland MN, Saffery R, Ranganathan S. Gene modifiers of cystic fibrosis lung disease: A systematic review. Pediatr Pulmonol 2019; 54:1356-1366. [PMID: 31140758 DOI: 10.1002/ppul.24366] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 05/03/2019] [Accepted: 05/05/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Lung disease is the major source of morbidity and mortality in cystic fibrosis (CF), with large variability in severity between patients. Although accurate prediction of lung disease severity would be extremely useful, no robust methods exist. Twin and sibling studies have highlighted the importance of non-cystic fibrosis transmembrane conductance regulator (CFTR) genes in determining lung disease severity but how these impact on the severity in CF remains unclear. METHODS A systematic review was undertaken to answer the question "In patients with CF which non-CFTR genes modify the severity of lung disease?" The method for this systematic review was based upon the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)" statement, with a narrative synthesis of results planned. RESULTS A total of 1168 articles were screened for inclusion, with 275 articles undergoing detailed assessment for inclusion. One hundred and forty articles were included. Early studies focused on candidate genes, whereas more recent studies utilized genome-wide approaches and also examined epigenetic mechanisms, gene expression, and therapeutic response. DISCUSSION A large body of evidence regarding non-CFTR gene modifiers of lung disease severity has been generated, examining a wide array of genes. Limitations to existing studies include heterogeneity in outcome measures used, limited replication, and relative lack of clinical impact. Future work examining non-CFTR gene modifiers will have to overcome these limitations if gene modifiers are to have a meaningful role in the care of patients with CF.
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Affiliation(s)
- Shivanthan Shanthikumar
- Respiratory and Sleep Medicine Department, Royal Children's Hospital, Melbourne, Australia.,Respiratory Diseases Department, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, The University of Melbourne, Australia
| | - Melanie N Neeland
- Department of Paediatrics, The University of Melbourne, Australia.,Centre of Food and Allergy Research, Murdoch Children's Research Institute, Melbourne, Australia
| | - Richard Saffery
- Department of Paediatrics, The University of Melbourne, Australia.,Cancer & Disease Epigenetics, Murdoch Children's Research Institute, Melbourne, Australia
| | - Sarath Ranganathan
- Respiratory and Sleep Medicine Department, Royal Children's Hospital, Melbourne, Australia.,Respiratory Diseases Department, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, The University of Melbourne, Australia
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27
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Welsner M, Straßburg S, Taube C, Sutharsan S. Use of ivacaftor in late diagnosed cystic fibrosis monozygotic twins heterozygous for F508del and R117H-7T - a case report. BMC Pulm Med 2019; 19:76. [PMID: 30975115 PMCID: PMC6458608 DOI: 10.1186/s12890-019-0840-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 03/28/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND CFTR modulator therapy with ivacaftor is a treatment option for Cystic Fibrosis (CF) patients with at least one copy of a R117H-7T mutation in the CFTR gene. Desirable effects of this therapy are improvement of lung function, decrease in exacerbation rate, normalization or reduction of sweat chloride and weight gain. Monogenetic CF-twins carry identical genetic information, so therapy response and side effects are expected to be nearly identical under this specific therapy. CASE PRESENTATION In monozygotic twins, at the age of 55, two pathogenic variants in the CFTR gene (F508del and R117H-7T) were detected. Both patients presented with a borderline sweat test (30-59 mmol/L) and despite the same genetic information and similar life circumstances the disease proceeds completely different. While one patient has severe pulmonary involvement with chronic P. aeruginosa infection, her twin sister is almost unimpaired. Liver or pancreatic involvement was not seen in either patient. Due to the presence of one copy of a R117H-7T mutation, CFTR modulator therapy with ivacaftor was initiated in both. Response and side effects were significantly different. In the less affected patient, we observed an improvement in lung function and a normalization of sweat chloride. In the severely affected patient, no functional response to treatment was seen, but stabilization of the disease state with a decrease in exacerbation and hospitalization rate and weight gain as well as a normalization of sweat chloride. There was an increase in liver enzymes in the less affected patient, which normalized after halving the dose of ivacaftor, while the therapeutic effect was maintained. CONCLUSIONS Despite nearly identical genetic information, as in monogenetic twins, therapy response and onset of side effects of CFTR modulating therapy are very different. In patients with late diagnosis and severe pulmonary involvement, ivacaftor does not seem to improve lung function, whereas in patients with late diagnosis and low disease severity a relevant therapy response was obtained. In addition to lung function, additional clinical parameters such as reduction of exacerbation and hospitalization rate and weight gain should be used to assess therapy response, especially in severely affected patients.
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Affiliation(s)
- Matthias Welsner
- Department of Pulmonary Medicine, University Hospital Essen - Ruhrlandklinik, Adult Cystic Fibrosis Center, University of Duisburg-Essen, Tueschener Weg 40, 45329, Essen, Germany.
| | - Svenja Straßburg
- Department of Pulmonary Medicine, University Hospital Essen - Ruhrlandklinik, Adult Cystic Fibrosis Center, University of Duisburg-Essen, Tueschener Weg 40, 45329, Essen, Germany
| | - Christian Taube
- Department of Pulmonary Medicine, University Hospital Essen - Ruhrlandklinik, Adult Cystic Fibrosis Center, University of Duisburg-Essen, Tueschener Weg 40, 45329, Essen, Germany
| | - Sivagurunathan Sutharsan
- Department of Pulmonary Medicine, University Hospital Essen - Ruhrlandklinik, Adult Cystic Fibrosis Center, University of Duisburg-Essen, Tueschener Weg 40, 45329, Essen, Germany
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