1
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Kim YJ, Krainer AR. Antisense Oligonucleotide Therapeutics for Cystic Fibrosis: Recent Developments and Perspectives. Mol Cells 2023; 46:10-20. [PMID: 36697233 PMCID: PMC9880599 DOI: 10.14348/molcells.2023.2172] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 01/27/2023] Open
Abstract
Antisense oligonucleotide (ASO) technology has become an attractive therapeutic modality for various diseases, including Mendelian disorders. ASOs can modulate the expression of a target gene by promoting mRNA degradation or changing pre-mRNA splicing, nonsense-mediated mRNA decay, or translation. Advances in medicinal chemistry and a deeper understanding of post-transcriptional mechanisms have led to the approval of several ASO drugs for diseases that had long lacked therapeutic options. For instance, an ASO drug called nusinersen became the first approved drug for spinal muscular atrophy, improving survival and the overall disease course. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF). Although Trikafta and other CFTR-modulation therapies benefit most CF patients, there is a significant unmet therapeutic need for a subset of CF patients. In this review, we introduce ASO therapies and their mechanisms of action, describe the opportunities and challenges for ASO therapeutics for CF, and discuss the current state and prospects of ASO therapies for CF.
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Affiliation(s)
- Young Jin Kim
- Department of Pediatrics, Mount Sinai Hospital, New York, NY 10029, USA
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2
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Ensinck MM, Carlon MS. One Size Does Not Fit All: The Past, Present and Future of Cystic Fibrosis Causal Therapies. Cells 2022; 11:cells11121868. [PMID: 35740997 PMCID: PMC9220995 DOI: 10.3390/cells11121868] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 05/25/2022] [Accepted: 05/28/2022] [Indexed: 02/04/2023] Open
Abstract
Cystic fibrosis (CF) is the most common monogenic disorder, caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Over the last 30 years, tremendous progress has been made in understanding the molecular basis of CF and the development of treatments that target the underlying defects in CF. Currently, a highly effective CFTR modulator treatment (Kalydeco™/Trikafta™) is available for 90% of people with CF. In this review, we will give an extensive overview of past and ongoing efforts in the development of therapies targeting the molecular defects in CF. We will discuss strategies targeting the CFTR protein (i.e., CFTR modulators such as correctors and potentiators), its cellular environment (i.e., proteostasis modulation, stabilization at the plasma membrane), the CFTR mRNA (i.e., amplifiers, nonsense mediated mRNA decay suppressors, translational readthrough inducing drugs) or the CFTR gene (gene therapies). Finally, we will focus on how these efforts can be applied to the 15% of people with CF for whom no causal therapy is available yet.
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Affiliation(s)
- Marjolein M. Ensinck
- Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Flanders, Belgium;
| | - Marianne S. Carlon
- Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Flanders, Belgium;
- Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), Department of Chronic Diseases and Metabolism, KU Leuven, 3000 Leuven, Flanders, Belgium
- Correspondence:
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3
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Kim YJ, Nomakuchi T, Papaleonidopoulou F, Yang L, Zhang Q, Krainer AR. Gene-specific nonsense-mediated mRNA decay targeting for cystic fibrosis therapy. Nat Commun 2022; 13:2978. [PMID: 35624092 PMCID: PMC9142507 DOI: 10.1038/s41467-022-30668-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 05/06/2022] [Indexed: 12/20/2022] Open
Abstract
Low CFTR mRNA expression due to nonsense-mediated mRNA decay (NMD) is a major hurdle in developing a therapy for cystic fibrosis (CF) caused by the W1282X mutation in the CFTR gene. CFTR-W1282X truncated protein retains partial function, so increasing its levels by inhibiting NMD of its mRNA will likely be beneficial. Because NMD regulates the normal expression of many genes, gene-specific stabilization of CFTR-W1282X mRNA expression is more desirable than general NMD inhibition. Synthetic antisense oligonucleotides (ASOs) designed to prevent binding of exon junction complexes (EJC) downstream of premature termination codons (PTCs) attenuate NMD in a gene-specific manner. We describe cocktails of three ASOs that specifically increase the expression of CFTR-W1282X mRNA and CFTR protein upon delivery into human bronchial epithelial cells. This treatment increases the CFTR-mediated chloride current. These results set the stage for clinical development of an allele-specific therapy for CF caused by the W1282X mutation. The W1282X nonsense mutation in the CFTR gene causes cystic fibrosis by reducing its mRNA and functional protein levels. Here the authors developed antisense-oligonucleotide cocktails that restore CFTR protein function by gene-specific stabilization of CFTR mRNA.
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Affiliation(s)
- Young Jin Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, 11794, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Tomoki Nomakuchi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA.,Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Foteini Papaleonidopoulou
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Francis Crick Institute, London, 1140062, UK
| | - Lucia Yang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, 11794, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Qian Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Molecular and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.
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4
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Sharma J, Du M, Wong E, Mutyam V, Li Y, Chen J, Wangen J, Thrasher K, Fu L, Peng N, Tang L, Liu K, Mathew B, Bostwick RJ, Augelli-Szafran CE, Bihler H, Liang F, Mahiou J, Saltz J, Rab A, Hong J, Sorscher EJ, Mendenhall EM, Coppola CJ, Keeling KM, Green R, Mense M, Suto MJ, Rowe SM, Bedwell DM. A small molecule that induces translational readthrough of CFTR nonsense mutations by eRF1 depletion. Nat Commun 2021; 12:4358. [PMID: 34272367 PMCID: PMC8285393 DOI: 10.1038/s41467-021-24575-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/22/2021] [Indexed: 11/09/2022] Open
Abstract
Premature termination codons (PTCs) prevent translation of a full-length protein and trigger nonsense-mediated mRNA decay (NMD). Nonsense suppression (also termed readthrough) therapy restores protein function by selectively suppressing translation termination at PTCs. Poor efficacy of current readthrough agents prompted us to search for better compounds. An NMD-sensitive NanoLuc readthrough reporter was used to screen 771,345 compounds. Among the 180 compounds identified with readthrough activity, SRI-37240 and its more potent derivative SRI-41315, induce a prolonged pause at stop codons and suppress PTCs associated with cystic fibrosis in immortalized and primary human bronchial epithelial cells, restoring CFTR expression and function. SRI-41315 suppresses PTCs by reducing the abundance of the termination factor eRF1. SRI-41315 also potentiates aminoglycoside-mediated readthrough, leading to synergistic increases in CFTR activity. Combining readthrough agents that target distinct components of the translation machinery is a promising treatment strategy for diseases caused by PTCs. Premature termination codons can cause early translation termination and lead to disease. Here the authors perform a screen to identify compounds with readthrough activity and show that these reduce eRF1 levels to suppress premature termination associated with cystic fibrosis.
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Affiliation(s)
- Jyoti Sharma
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Microbiology, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Ming Du
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Eric Wong
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Venkateshwar Mutyam
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Yao Li
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Jianguo Chen
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Jamie Wangen
- Department of Molecular Biology and Genetics and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kari Thrasher
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Lianwu Fu
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Ning Peng
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Liping Tang
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Kaimao Liu
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | | | | | | | - Hermann Bihler
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Feng Liang
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Jerome Mahiou
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Josef Saltz
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | - Andras Rab
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Jeong Hong
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Eric J Sorscher
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Eric M Mendenhall
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL, USA
| | - Candice J Coppola
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL, USA
| | - Kim M Keeling
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - Rachel Green
- Department of Molecular Biology and Genetics and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Martin Mense
- CFFT Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | | | - Steven M Rowe
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.,Department of Pediatrics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA
| | - David M Bedwell
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), Birmingham, AL, USA. .,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), Birmingham, AL, USA.
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5
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Sharma J, Abbott J, Klaskala L, Zhao G, Birket SE, Rowe SM. A Novel G542X CFTR Rat Model of Cystic Fibrosis Is Sensitive to Nonsense Mediated Decay. Front Physiol 2020; 11:611294. [PMID: 33391025 PMCID: PMC7772197 DOI: 10.3389/fphys.2020.611294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/19/2020] [Indexed: 12/22/2022] Open
Abstract
Nonsense mutations that lead to the insertion of a premature termination codon (PTC) in the cystic fibrosis transmembrane conductance regulator (CFTR) transcript affect 11% of patients with cystic fibrosis (CF) worldwide and are associated with severe disease phenotype. While CF rat models have contributed significantly to our understanding of CF disease pathogenesis, there are currently no rat models available for studying CF nonsense mutations. Here we created and characterized the first homozygous CF rat model that bears the CFTR G542X nonsense mutation in the endogenous locus using CRISPR/Cas9 gene editing. In addition to displaying severe CF manifestations and developmental defects such as reduced growth, abnormal tooth enamel, and intestinal obstruction, CFTR G542X knockin rats demonstrated an absence of CFTR function in tracheal and intestinal sections as assessed by nasal potential difference and transepithelial short-circuit current measurements. Reduced CFTR mRNA levels in the model further suggested sensitivity to nonsense-mediated decay, a pathway elicited by the presence of PTCs that degrades the PTC-bearing transcripts and thus further diminishes the level of CFTR protein. Although functional restoration of CFTR was observed in G542X rat tracheal epithelial cells in response to single readthrough agent therapy, therapeutic efficacy was not observed in G542X knockin rats in vivo. The G542X rat model provides an invaluable tool for the identification and in vivo validation of potential therapies for CFTR nonsense mutations.
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Affiliation(s)
- Jyoti Sharma
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Joseph Abbott
- Horizon Discovery Group, PLC, St. Louis, MO, United States
| | | | - Guojun Zhao
- Horizon Discovery Group, PLC, St. Louis, MO, United States
| | - Susan E. Birket
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Steven M. Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
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6
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Mall MA, Mayer-Hamblett N, Rowe SM. Cystic Fibrosis: Emergence of Highly Effective Targeted Therapeutics and Potential Clinical Implications. Am J Respir Crit Care Med 2020; 201:1193-1208. [PMID: 31860331 DOI: 10.1164/rccm.201910-1943so] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cystic fibrosis (CF) remains the most common life-shortening hereditary disease in white populations, with high morbidity and mortality related to chronic airway mucus obstruction, inflammation, infection, and progressive lung damage. In 1989, the discovery that CF is caused by mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene that encodes a cAMP-dependent anion channel vital for proper Cl- and HCO3- transport across epithelial surfaces provided a solid foundation for unraveling underlying disease mechanisms and the development of therapeutics targeting the basic defect in people with CF. In this review, we focus on recent advances in our understanding of the molecular defects caused by different classes of CFTR mutations, implications for pharmacological rescue of mutant CFTR, and insights into how CFTR dysfunction impairs key host defense mechanisms, such as mucociliary clearance and bacterial killing in CF airways. Furthermore, we review the path that led to the recent breakthrough in the development of highly effective CFTR-directed therapeutics, now applicable for up to 90% of people with CF who carry responsive CFTR mutations, including those with just a single copy of the most common F508del mutation. Finally, we discuss the remaining challenges and strategies to develop highly effective targeted therapies for all patients and the unprecedented potential of these novel therapies to transform CF from a fatal to a treatable chronic condition.
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Affiliation(s)
- Marcus A Mall
- Department of Pediatric Pulmonology, Immunology, and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,German Center for Lung Research (DZL), Berlin, Germany
| | - Nicole Mayer-Hamblett
- Department of Pediatrics and.,Department of Biostatistics, University of Washington, Seattle, Washington.,Seattle Children's Hospital, Seattle, Washington
| | - Steven M Rowe
- Department of Medicine.,Department of Pediatrics, and.,Department of Cell, Developmental and Integrative Biology, Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama
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7
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Strub MD, McCray, Jr. PB. Transcriptomic and Proteostasis Networks of CFTR and the Development of Small Molecule Modulators for the Treatment of Cystic Fibrosis Lung Disease. Genes (Basel) 2020; 11:genes11050546. [PMID: 32414011 PMCID: PMC7288469 DOI: 10.3390/genes11050546] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/18/2022] Open
Abstract
Cystic fibrosis (CF) is a lethal autosomal recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The diversity of mutations and the multiple ways by which the protein is affected present challenges for therapeutic development. The observation that the Phe508del-CFTR mutant protein is temperature sensitive provided proof of principle that mutant CFTR could escape proteosomal degradation and retain partial function. Several specific protein interactors and quality control checkpoints encountered by CFTR during its proteostasis have been investigated for therapeutic purposes, but remain incompletely understood. Furthermore, pharmacological manipulation of many CFTR interactors has not been thoroughly investigated for the rescue of Phe508del-CFTR. However, high-throughput screening technologies helped identify several small molecule modulators that rescue CFTR from proteosomal degradation and restore partial function to the protein. Here, we discuss the current state of CFTR transcriptomic and biogenesis research and small molecule therapy development. We also review recent progress in CFTR proteostasis modulators and discuss how such treatments could complement current FDA-approved small molecules.
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Affiliation(s)
- Matthew D. Strub
- Interdisciplinary Graduate Program in Genetics, The University of Iowa, Iowa City, IA 52242, USA;
- Stead Family Department of Pediatrics, The University of Iowa, Iowa City, IA 52242, USA
| | - Paul B. McCray, Jr.
- Interdisciplinary Graduate Program in Genetics, The University of Iowa, Iowa City, IA 52242, USA;
- Stead Family Department of Pediatrics, The University of Iowa, Iowa City, IA 52242, USA
- Correspondence: ; Tel.: +1-(319)-335-6844
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8
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Didiasova M, Banning A, Brennenstuhl H, Jung-Klawitter S, Cinquemani C, Opladen T, Tikkanen R. Succinic Semialdehyde Dehydrogenase Deficiency: An Update. Cells 2020; 9:cells9020477. [PMID: 32093054 PMCID: PMC7072817 DOI: 10.3390/cells9020477] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 02/06/2023] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADH-D) is a genetic disorder that results from the aberrant metabolism of the neurotransmitter γ-amino butyric acid (GABA). The disease is caused by impaired activity of the mitochondrial enzyme succinic semialdehyde dehydrogenase. SSADH-D manifests as varying degrees of mental retardation, autism, ataxia, and epileptic seizures, but the clinical picture is highly heterogeneous. So far, there is no approved curative therapy for this disease. In this review, we briefly summarize the molecular genetics of SSADH-D, the past and ongoing clinical trials, and the emerging features of the molecular pathogenesis, including redox imbalance and mitochondrial dysfunction. The main aim of this review is to discuss the potential of further therapy approaches that have so far not been tested in SSADH-D, such as pharmacological chaperones, read-through drugs, and gene therapy. Special attention will also be paid to elucidating the role of patient advocacy organizations in facilitating research and in the communication between researchers and patients.
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Affiliation(s)
- Miroslava Didiasova
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; (M.D.); (A.B.)
| | - Antje Banning
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; (M.D.); (A.B.)
| | - Heiko Brennenstuhl
- Division of Neuropediatrics and Metabolic Medicine, Department of General Pediatrics, University Children’s Hospital Heidelberg, 69120 Heidelberg, Germany; (H.B.); (S.J.-K.); (T.O.)
| | - Sabine Jung-Klawitter
- Division of Neuropediatrics and Metabolic Medicine, Department of General Pediatrics, University Children’s Hospital Heidelberg, 69120 Heidelberg, Germany; (H.B.); (S.J.-K.); (T.O.)
| | | | - Thomas Opladen
- Division of Neuropediatrics and Metabolic Medicine, Department of General Pediatrics, University Children’s Hospital Heidelberg, 69120 Heidelberg, Germany; (H.B.); (S.J.-K.); (T.O.)
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; (M.D.); (A.B.)
- Correspondence: ; Tel.: +49-641-9947-420
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9
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Cho DY, Skinner D, Mackey C, Lampkin HB, Elder JB, Lim DJ, Zhang S, McCormick J, Tearney GJ, Rowe SM, Woodworth BA. Herbal dry extract BNO 1011 improves clinical and mucociliary parameters in a rabbit model of chronic rhinosinusitis. Int Forum Allergy Rhinol 2019; 9:629-637. [PMID: 30657641 DOI: 10.1002/alr.22290] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/22/2018] [Accepted: 12/27/2018] [Indexed: 11/08/2022]
Abstract
BACKGROUND Enhancing chloride (Cl- ) secretion in sinus epithelia represents a novel therapeutic approach to chronic rhinosinusitis (CRS). Herbal dry extract BNO 1011 enhances mucociliary clearance (MCC) via upregulation of Cl- secretion in sinonasal cultures in vitro and murine epithelium in vivo. The objective of this study is to evaluate whether the BNO 1011 improves MCC and clinical parameters in a rabbit model of CRS. METHODS After the development of CRS in 30 New Zealand white rabbits, animals were randomly assigned to receive oral placebo (n = 10), BNO 1011 (low dose [LD], 25 mg/kg/daily) (n = 10), or BNO1011 (high dose [HD], 125 mg/kg/daily) (n = 10) for 4 weeks. Outcomes included sinus opacification (Kerschner's rabbit sinus CT grade), maxillary epithelial Cl- secretion (sinus potential difference [PD] assay), airway surface liquid (ASL) depth using micro-optical coherence tomography (μOCT), and submucosal gland density (SMD) on histopathology. Outcome parameters were analyzed by 2 blinded investigators. RESULTS BNO 1011 significantly cleared sinus opacification (HD = 1.21 ± 0.63, LD = 1.26 ± 0.37,) compared to placebo (4.02 ± 0.92) (p = 0.009). BNO 1011 resulted in markedly greater mean sinus PD polarization (HD = -12.23 ± 1.4 mV, LD = -12.0 ± 3.0 mV) when compared to rabbits treated with placebo (-4.1 ± 1.1 mV) (p = 0.03). ASL depth was significantly improved when treated with HD (4.08 ± 0.06 μm) and LD (4.05 ± 0.06 μm) compared to placebo (3.5 ± 0.05 μm) (post hoc analysis, p < 0.0001). Histologically, epithelial thickness (HD = 10.0 ± 0.7 μm; LD = 13.7 ± 0.9 μm; placebo = 21.1 ± 2.3 μm; p < 0.005), subepithelial thickness (HD = 63.1 ± 6.6 μm; LD = 103.2 ± 6.7 μm; placebo = 113.3 ± 6.0 μm; p < 0.001), and SMD (HD = 22.2 ± 2.9%; LD = 31.8 ± 1.1%; placebo = 43.8 ± 1.7%; p < 0.0001) were noticeably better with the HD. CONCLUSION Herbal dry extract BNO 1011 improves radiographic, histologic, and MCC parameters in a rabbit model of CRS.
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Affiliation(s)
- Do-Yeon Cho
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Daniel Skinner
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL
| | - Calvin Mackey
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL
| | - Harold B Lampkin
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL
| | - Jeffrey Brent Elder
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL
| | - Dong Jin Lim
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL
| | - Shaoyan Zhang
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL
| | - Justin McCormick
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL
| | - Guillermo J Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA
| | - Steven M Rowe
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL.,Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.,Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL.,Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Bradford A Woodworth
- Department of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
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10
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Beka M, Leal T. Nasal Potential Difference to Quantify Trans-epithelial Ion Transport in Mice. J Vis Exp 2018. [PMID: 30035761 DOI: 10.3791/57934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The nasal potential difference test has been used for almost three decades to assist in the diagnosis of cystic fibrosis (CF). It has proven to be helpful in cases of attenuated, oligo- or mono-symptomatic forms of CF usually diagnosed later in life, and of CF-related disorders such as congenital bilateral absence of vas deferens, idiopathic chronic pancreatitis, allergic bronchopulmonary aspergillosis, and bronchiectasis. In both clinical and preclinical settings, the test has been used as a biomarker to quantify responses to targeted therapeutic strategies for CF. Adapting the test to a mouse is challenging and can entail an associated mortality. This paper describes the adequate depth of anesthesia required to maintain a nasal catheter in situ for continuous perfusion. It lists measures to avoid broncho-aspiration of solutions perfused in the nose. It also describes the animal care at the end of the test, including administration of a combination of antidotes of the anesthetic drugs, leading to rapidly reversing the anesthesia with full recovery of the animals. Representative data obtained from a CF and a wild-type mouse show that the test discriminates between CF and non-CF. Altogether, the protocol described here allows reliable measurements of the functional status of trans-epithelial chloride and sodium transporters in spontaneously breathing mice, as well as multiple tests in the same animal while reducing test-related mortality.
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Affiliation(s)
- Mathilde Beka
- Louvain Center for Toxicology and Applied Pharmacology (LTAP), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain
| | - Teresinha Leal
- Louvain Center for Toxicology and Applied Pharmacology (LTAP), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain;
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11
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Pranke I, Bidou L, Martin N, Blanchet S, Hatton A, Karri S, Cornu D, Costes B, Chevalier B, Tondelier D, Girodon E, Coupet M, Edelman A, Fanen P, Namy O, Sermet-Gaudelus I, Hinzpeter A. Factors influencing readthrough therapy for frequent cystic fibrosis premature termination codons. ERJ Open Res 2018; 4:00080-2017. [PMID: 29497617 PMCID: PMC5827411 DOI: 10.1183/23120541.00080-2017] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 12/22/2017] [Indexed: 01/17/2023] Open
Abstract
Premature termination codons (PTCs) are generally associated with severe forms of genetic diseases. Readthrough of in-frame PTCs using small molecules is a promising therapeutic approach. Nonetheless, the outcome of preclinical studies has been low and variable. Treatment efficacy depends on: 1) the level of drug-induced readthrough, 2) the amount of target transcripts, and 3) the activity of the recoded protein. The aim of the present study was to identify, in the cystic fibrosis transmembrane conductance regulator (CFTR) model, recoded channels from readthrough therapy that may be enhanced using CFTR modulators. First, drug-induced readthrough of 15 PTCs was measured using a dual reporter system under basal conditions and in response to gentamicin and negamycin. Secondly, exon skipping associated with these PTCs was evaluated with a minigene system. Finally, incorporated amino acids were identified by mass spectrometry and the function of the predicted recoded CFTR channels corresponding to these 15 PTCs was measured. Nonfunctional channels were subjected to CFTR-directed ivacaftor-lumacaftor treatments. The results demonstrated that CFTR modulators increased activity of recoded channels, which could also be confirmed in cells derived from a patient. In conclusion, this work will provide a framework to adapt treatments to the patient's genotype by identifying the most efficient molecule for each PTC and the recoded channels needing co-therapies to rescue channel function.
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Affiliation(s)
- Iwona Pranke
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
- Université Paris Descartes, Paris, France
- Both authors contributed equally
| | - Laure Bidou
- Sorbonne Universités, Université Pierre et Marie Curie, UPMC, Paris, France
- Institute for Integrative Biology of the Cell, I2BC, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
- Both authors contributed equally
| | - Natacha Martin
- INSERM, U955, Institut de Recherche Henri Mondor, Créteil, France
| | - Sandra Blanchet
- Institute for Integrative Biology of the Cell, I2BC, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Aurélie Hatton
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
- Université Paris Descartes, Paris, France
| | - Sabrina Karri
- Institute for Integrative Biology of the Cell, I2BC, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - David Cornu
- Institute for Integrative Biology of the Cell, I2BC, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Bruno Costes
- INSERM, U955, Institut de Recherche Henri Mondor, Créteil, France
- Université Paris-Est, Créteil, France
| | - Benoit Chevalier
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
- Université Paris Descartes, Paris, France
| | - Danielle Tondelier
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
- Université Paris Descartes, Paris, France
| | - Emmanuelle Girodon
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
- Laboratoire de Génétique et Biologie Moléculaires, HUPC Hôpital Cochin, AP-HP, Paris, France
| | - Matthieu Coupet
- Institute for Integrative Biology of the Cell, I2BC, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Aleksander Edelman
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
- Université Paris Descartes, Paris, France
| | - Pascale Fanen
- INSERM, U955, Institut de Recherche Henri Mondor, Créteil, France
- Université Paris-Est, Créteil, France
- Dept of Genetics, GH Henri Mondor, AP-HP, Créteil, France
| | - Olivier Namy
- Institute for Integrative Biology of the Cell, I2BC, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Isabelle Sermet-Gaudelus
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
- Université Paris Descartes, Paris, France
| | - Alexandre Hinzpeter
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
- Université Paris Descartes, Paris, France
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12
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Oren YS, Pranke IM, Kerem B, Sermet-Gaudelus I. The suppression of premature termination codons and the repair of splicing mutations in CFTR. Curr Opin Pharmacol 2017; 34:125-131. [PMID: 29128743 DOI: 10.1016/j.coph.2017.09.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/20/2017] [Accepted: 09/26/2017] [Indexed: 12/31/2022]
Abstract
Premature termination codons (PTC) originate from nucleotide substitution introducing an in-frame PTC. They induce truncated, usually non-functional, proteins, degradation of the PTC containing transcripts by the nonsense-mediated decay (NMD) pathway and abnormal exon skipping. Readthrough compounds facilitate near cognate amino-acyl-tRNA incorporation, leading potentially to restoration of a functional full-length protein. Splicing mutations can lead to aberrantly spliced transcripts by creating a cryptic splice site or destroying a normal site. Most mutations result in disruption of the open reading frame and activation of NMD. Antisense oligonucleotides are single stranded short synthetic RNA-like molecules chemically modified to improve their stability and ability to recognize their target RNAs and modify the splice site. This review focuses on recent developments in therapies aiming to improve the health of CF patients carrying nonsense or splicing mutations.
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Affiliation(s)
- Yifat S Oren
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel; SpliSense Therapeutics, Givat Ram Campus, Hebrew University, Jerusalem, Israel
| | - Iwona M Pranke
- INSERM U 1151, Institut Necker Enfants Malades, Paris, France; Université Paris Sorbonne, France
| | - Batsheva Kerem
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel.
| | - Isabelle Sermet-Gaudelus
- INSERM U 1151, Institut Necker Enfants Malades, Paris, France; Unité de Pneumo-Allergologie Pédiatrique, Centre de Ressources et de Compétence de la Mucoviscidose, Hôpital Necker Enfants Malades, Paris, France; Université Paris Sorbonne, France.
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13
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Zak SM, Clancy JP, Brewington JJ. CFTR functional assays in drug development. Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1393413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Sara M. Zak
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, USA
| | - John P. Clancy
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, USA
| | - John J. Brewington
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, USA
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14
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Solomon GM, Liu B, Sermet-Gaudelus I, Fajac I, Wilschanski M, Vermeulen F, Rowe SM. A multiple reader scoring system for Nasal Potential Difference parameters. J Cyst Fibros 2017; 16:573-578. [PMID: 28465124 DOI: 10.1016/j.jcf.2017.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 03/10/2017] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND Nasal Potential Difference (NPD) is a biomarker of CFTR activity used to diagnose CF and monitor experimental therapies. Limited studies have been performed to assess agreement between expert readers of NPD interpretation using a scoring algorithm. METHODS We developed a standardized scoring algorithm for "interpretability" and "confidence" for PD (potential difference) measures, and sought to determine the degree of agreement on NPD parameters between trained readers. RESULTS There was excellent agreement for interpretability between NPD readers for CF and fair agreement for normal tracings but slight agreement of interpretability in indeterminate tracings. Amongst interpretable tracings, excellent correlation of mean scores for Ringer's Baseline PD, Δamiloride, and ΔCl-free+Isoproterenol was observed. There was slight agreement regarding confidence of the interpretable PD tracings, resulting in divergence of the Ringers and Δamiloride, and ΔCl-free+Isoproterenol PDs between "high" and "low" confidence CF tracings. CONCLUSION A multi-reader process with adjudication is important for scoring NPDs for diagnosis and in monitoring of CF clinical trials.
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Affiliation(s)
- George M Solomon
- Department of Medicine, The Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Bo Liu
- Department of Medicine, The Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Isabelle Sermet-Gaudelus
- Hôpital Necker-Enfants Malades, France; Université Paris René Descartes, Sorbonne Paris Cité, Paris, France
| | - Isabelle Fajac
- Université Paris René Descartes, Sorbonne Paris Cité, Paris, France; AP-HP, Hôpital Cochin, Service de Physiologie et Explorations Fonctionnelles, Paris, France
| | | | | | - Steven M Rowe
- Department of Medicine, The Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
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15
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Mutyam V, Du M, Xue X, Keeling KM, White EL, Bostwick JR, Rasmussen L, Liu B, Mazur M, Hong JS, Falk Libby E, Liang F, Shang H, Mense M, Suto MJ, Bedwell DM, Rowe SM. Discovery of Clinically Approved Agents That Promote Suppression of Cystic Fibrosis Transmembrane Conductance Regulator Nonsense Mutations. Am J Respir Crit Care Med 2016; 194:1092-1103. [PMID: 27104944 PMCID: PMC5114449 DOI: 10.1164/rccm.201601-0154oc] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/21/2016] [Indexed: 01/03/2023] Open
Abstract
RATIONALE Premature termination codons (PTCs) in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF). Several agents are known to suppress PTCs but are poorly efficacious or toxic. OBJECTIVES To determine whether there are clinically available agents that elicit translational readthrough and improve CFTR function sufficient to confer therapeutic benefit to patients with CF with PTCs. METHODS Two independent screens, firefly luciferase and CFTR-mediated transepithelial chloride conductance assay, were performed on a library of 1,600 clinically approved compounds using fisher rat thyroid cells stably transfected with stop codons. Select agents were further evaluated using secondary screening assays including short circuit current analysis on primary cells from patients with CF. In addition, the effect of CFTR modulators (ivacaftor) was tested in combination with the most efficacious agents. MEASUREMENTS AND MAIN RESULTS From the primary screen, 48 agents were selected as potentially active. Following confirmatory tests in the transepithelial chloride conductance assay and prioritizing agents based on favorable pharmacologic properties, eight agents were advanced for secondary screening. Ivacaftor significantly increased short circuit current following forskolin stimulation in cells treated with pyranoradine tetraphosphate, potassium p-aminobenzoate, and escin as compared with vehicle control. Escin, an herbal agent, consistently induced readthrough activity as demonstrated by enhanced CFTR expression and function in vitro. CONCLUSIONS Clinically approved drugs identified as potential readthrough agents, in combination with ivacaftor, may induce nonsense suppression to restore therapeutic levels of CFTR function. One or more agents may be suitable to advance to human testing.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Marina Mazur
- Gregory Fleming James Cystic Fibrosis Research Center
| | - Jeong S. Hong
- Gregory Fleming James Cystic Fibrosis Research Center
- Department of Cell Developmental and Integrative Biology, and
| | | | - Feng Liang
- Cystic Fibrosis Foundation Therapeutics, Boston, Massachusetts
| | - Haibo Shang
- Cystic Fibrosis Foundation Therapeutics, Boston, Massachusetts
| | - Martin Mense
- Cystic Fibrosis Foundation Therapeutics, Boston, Massachusetts
| | | | - David M. Bedwell
- Department of Microbiology
- Gregory Fleming James Cystic Fibrosis Research Center
| | - Steven M. Rowe
- Department of Medicine
- Gregory Fleming James Cystic Fibrosis Research Center
- Department of Cell Developmental and Integrative Biology, and
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
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16
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Biomarkers for cystic fibrosis drug development. J Cyst Fibros 2016; 15:714-723. [PMID: 28215711 DOI: 10.1016/j.jcf.2016.10.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 10/12/2016] [Indexed: 12/14/2022]
Abstract
PURPOSE To provide a review of the status of biomarkers in cystic fibrosis drug development, including regulatory definitions and considerations, a summary of biomarkers in current use with supportive data, current gaps, and future needs. METHODS Biomarkers are considered across several areas of CF drug development, including cystic fibrosis transmembrane conductance regulator modulation, infection, and inflammation. RESULTS Sweat chloride, nasal potential difference, and intestinal current measurements have been standardized and examined in the context of multicenter trials to quantify CFTR function. Detection and quantification of pathogenic bacteria in CF respiratory cultures (e.g.: Pseudomonas aeruginosa) are commonly used in early phase antimicrobial clinical trials, and to monitor safety of therapeutic interventions. Sputum (e.g.: neutrophil elastase, myeloperoxidase, calprotectin) and blood biomarkers (e.g.: C reactive protein, calprotectin, serum amyloid A) have had variable success in detecting response to inflammatory treatments. CONCLUSIONS Biomarkers are used throughout the drug development process in CF, and many have been used in early phase clinical trials to provide proof of concept, detect drug bioactivity, and inform dosing for later-phase studies. Advances in the precision of current biomarkers, and the identification of new biomarkers with 'omics-based technologies, are needed to accelerate CF drug development.
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17
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Schmidt BZ, Haaf JB, Leal T, Noel S. Cystic fibrosis transmembrane conductance regulator modulators in cystic fibrosis: current perspectives. Clin Pharmacol 2016; 8:127-140. [PMID: 27703398 PMCID: PMC5036583 DOI: 10.2147/cpaa.s100759] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mutations of the CFTR gene cause cystic fibrosis (CF), the most common recessive monogenic disease worldwide. These mutations alter the synthesis, processing, function, or half-life of CFTR, the main chloride channel expressed in the apical membrane of epithelial cells in the airway, intestine, pancreas, and reproductive tract. Lung disease is the most critical manifestation of CF. It is characterized by airway obstruction, infection, and inflammation that lead to fatal tissue destruction. In spite of great advances in early and multidisciplinary medical care, and in our understanding of the pathophysiology, CF is still considerably reducing the life expectancy of patients. This review highlights the current development in pharmacological modulators of CFTR, which aim at rescuing the expression and/or function of mutated CFTR. While only Kalydeco® and Orkambi® are currently available to patients, many other families of CFTR modulators are undergoing preclinical and clinical investigations. Drug repositioning and personalized medicine are particularly detailed in this review as they represent the most promising strategies for restoring CFTR function in CF.
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Affiliation(s)
- Béla Z Schmidt
- Stem Cell Biology and Embryology, Department of Development and Regeneration, Katholieke Universiteit Leuven, Leuven
| | - Jérémy B Haaf
- Louvain Center for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
| | - Teresinha Leal
- Louvain Center for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
| | - Sabrina Noel
- Louvain Center for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
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18
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Lopes-Pacheco M. CFTR Modulators: Shedding Light on Precision Medicine for Cystic Fibrosis. Front Pharmacol 2016; 7:275. [PMID: 27656143 PMCID: PMC5011145 DOI: 10.3389/fphar.2016.00275] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/11/2016] [Indexed: 12/15/2022] Open
Abstract
Cystic fibrosis (CF) is the most common life-threatening monogenic disease afflicting Caucasian people. It affects the respiratory, gastrointestinal, glandular and reproductive systems. The major cause of morbidity and mortality in CF is the respiratory disorder caused by a vicious cycle of obstruction of the airways, inflammation and infection that leads to epithelial damage, tissue remodeling and end-stage lung disease. Over the past decades, life expectancy of CF patients has increased due to early diagnosis and improved treatments; however, these patients still present limited quality of life. Many attempts have been made to rescue CF transmembrane conductance regulator (CFTR) expression, function and stability, thereby overcoming the molecular basis of CF. Gene and protein variances caused by CFTR mutants lead to different CF phenotypes, which then require different treatments to quell the patients' debilitating symptoms. In order to seek better approaches to treat CF patients and maximize therapeutic effects, CFTR mutants have been stratified into six groups (although several of these mutations present pleiotropic defects). The research with CFTR modulators (read-through agents, correctors, potentiators, stabilizers and amplifiers) has achieved remarkable progress, and these drugs are translating into pharmaceuticals and personalized treatments for CF patients. This review summarizes the main molecular and clinical features of CF, emphasizes the latest clinical trials using CFTR modulators, sheds light on the molecular mechanisms underlying these new and emerging treatments, and discusses the major breakthroughs and challenges to treating all CF patients.
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Affiliation(s)
- Miquéias Lopes-Pacheco
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
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19
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Turnbull AR, Davies JC. New drug developments in the management of cystic fibrosis lung disease. Expert Opin Pharmacother 2016; 17:1103-12. [PMID: 27017976 DOI: 10.1517/14656566.2016.1157582] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Therapies for cystic fibrosis (CF) pulmonary disease have, until recently, all targeted downstream manifestations rather than the root cause of the disease. A step-change in our approach has been achieved in the last few years, with novel small-molecule CFTR modulating drugs entering the clinic. AREAS COVERED In this article, we will discuss the field of drug development for CF lung disease. The case will be made for the potential benefits of basic defect-targeted strategies, which will be described in detail. Novel therapies directed at the downstream pulmonary manifestations of CF - infection, inflammation, and mucus impaction - will be reviewed. Finally, we will speculate on future directions and challenges. EXPERT OPINION CF drug development is in an exciting phase, catalysed by the impressive results seen in patients with ivacaftor-responsive CFTR mutations. The research field is active with trials of novel therapies targeting the basic defect, alongside drugs targeting downstream effects. In order to detect potentially small improvements due to novel therapies, especially in the context of treating young patients with early disease, sensitive outcome measures and the coordinated efforts of collaborative research networks are crucial.
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Affiliation(s)
- Andrew R Turnbull
- a National Heart and Lung Institute, Imperial College , London , UK.,b Department of Paediatric Respiratory Medicine , Royal Brompton and Harefield NHS Foundation Trust , London , UK
| | - Jane C Davies
- a National Heart and Lung Institute, Imperial College , London , UK.,b Department of Paediatric Respiratory Medicine , Royal Brompton and Harefield NHS Foundation Trust , London , UK
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20
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Colemeadow J, Joyce H, Turcanu V. Precise treatment of cystic fibrosis – current treatments and perspectives for using CRISPR. EXPERT REVIEW OF PRECISION MEDICINE AND DRUG DEVELOPMENT 2016. [DOI: 10.1080/23808993.2016.1146077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Trimble AT, Donaldson SH. CFTR Modulator Therapies for Cystic Fibrosis. PEDIATRIC ALLERGY, IMMUNOLOGY, AND PULMONOLOGY 2015; 28:230-236. [PMID: 35923001 DOI: 10.1089/ped.2015.0583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The cloning of cystic fibrosis transmembrane conductance regulator (CFTR) set into motion a cascade of discoveries that have helped to reveal the underlying pathophysiologic basis of cystic fibrosis (CF). This discovery and the knowledge that followed have also provided the opportunity to target this basic defect, with the hope of reversing or preventing the serious clinical consequences that result from absent CFTR function. With the recent approval of 2 therapies that directly modulate CFTR function in more than half of the CF population, we are now at the beginning of a pathway to providing increasingly effective therapies that have the potential to provide a fundamental change in the outcome of most patients with CF.
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Affiliation(s)
- Aaron T Trimble
- Division of Pulmonary and Critical Care Medicine, Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Scott H Donaldson
- Division of Pulmonary and Critical Care Medicine, Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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22
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Tiddens HAWM, Puderbach M, Venegas JG, Ratjen F, Donaldson SH, Davis SD, Rowe SM, Sagel SD, Higgins M, Waltz DA. Novel outcome measures for clinical trials in cystic fibrosis. Pediatr Pulmonol 2015; 50:302-315. [PMID: 25641878 PMCID: PMC4365726 DOI: 10.1002/ppul.23146] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 10/20/2014] [Accepted: 11/02/2014] [Indexed: 12/25/2022]
Abstract
Cystic fibrosis (CF) is a common inherited condition caused by mutations in the gene encoding the CF transmembrane regulator protein. With increased understanding of the molecular mechanisms underlying CF and the development of new therapies there comes the need to develop new outcome measures to assess the disease, its progression and response to treatment. As there are limitations to the current endpoints accepted for regulatory purposes, a workshop to discuss novel endpoints for clinical trials in CF was held in Anaheim, California in November 2011. The pros and cons of novel outcome measures with potential utility for evaluation of novel treatments in CF were critically evaluated. The highlights of the 2011 workshop and subsequent advances in technologies and techniques that could be used to inform the development of clinical trial endpoints are summarized in this review. Pediatr Pulmonol. © 2014 The Authors. Pediatric Pulmonology published by Wiley Periodicals, Inc.
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Affiliation(s)
- Harm A W M Tiddens
- Department of Pediatric Pulmonology and Allergology, Department of Radiology, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Michael Puderbach
- Department for Diagnostic and Interventional Radiology, Hufeland Klinikum, Bad Langensalza, Germany
| | - Jose G Venegas
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Felix Ratjen
- Department of Pediatrics, Division of Respiratory Medicine, Hospital for Sick Children, University of Toronto, Toronto, Ontario
| | - Scott H Donaldson
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Stephanie D Davis
- Department of Pediatrics, James Whitcomb Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, Indiana
| | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Scott D Sagel
- Department of Pediatrics, Children's Hospital Colorado, University of Colorado School of Medicine, Denver, Colorado
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23
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Oren YS, McClure ML, Rowe SM, Sorscher EJ, Bester AC, Manor M, Kerem E, Rivlin J, Zahdeh F, Mann M, Geiger T, Kerem B. The unfolded protein response affects readthrough of premature termination codons. EMBO Mol Med 2014; 6:685-701. [PMID: 24705877 PMCID: PMC4023889 DOI: 10.1002/emmm.201303347] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
One-third of monogenic inherited diseases result from premature termination codons (PTCs). Readthrough of in-frame PTCs enables synthesis of full-length functional proteins. However, extended variability in the response to readthrough treatment is found among patients, which correlates with the level of nonsense transcripts. Here, we aimed to reveal cellular pathways affecting this inter-patient variability. We show that activation of the unfolded protein response (UPR) governs the response to readthrough treatment by regulating the levels of transcripts carrying PTCs. Quantitative proteomic analyses showed substantial differences in UPR activation between patients carrying PTCs, correlating with their response. We further found a significant inverse correlation between the UPR and nonsense-mediated mRNA decay (NMD), suggesting a feedback loop between these homeostatic pathways. We uncovered and characterized the mechanism underlying this NMD-UPR feedback loop, which augments both UPR activation and NMD attenuation. Importantly, this feedback loop enhances the response to readthrough treatment, highlighting its clinical importance. Altogether, our study demonstrates the importance of the UPR and its regulatory network for genetic diseases caused by PTCs and for cell homeostasis under normal conditions.
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Affiliation(s)
- Yifat S Oren
- Department of Genetics, The Hebrew University, Jerusalem, Israel
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Vermeulen F, Proesmans M, Boon M, De Boeck K. Improved repeatability of nasal potential difference with a larger surface catheter. J Cyst Fibros 2014; 14:317-23. [PMID: 25439742 DOI: 10.1016/j.jcf.2014.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 08/13/2014] [Accepted: 08/18/2014] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To increase the power of nasal potential difference (NPD) as a biomarker of CFTR function, improvement of its repeatability is needed. We evaluated the improvement in repeatability resulting from measuring NPD (1) over a larger surface area and (2) at a fixed location. METHODS To assess repeatability, NPD was measured on two occasions with a new method using a larger surface catheter at fixed locations on the nasal floor (LSC-floor(5cm) and LSC-floor(3cm)) or at the most negative basal potential (LSC-floor(max)); with a sidehole catheter on the nasal floor at 5 cm) from the nasal margin (SHC-floor(5cm)) or at the most negative potential (SHC-floor(max)); and with an endhole catheter below the inferior surface of the lower turbinate at the most negative potential (EHC-turb(max)). RESULTS The within-subject standard deviation (S(w)) for repeated measurements of the total chloride response in the controls was smallest with the LSC-floor at a fixed location (LSC-floor(5cm) 3.1 mV; 95% CI 2.3-4.6 mV) and highest with the SHC-floor (SHC-floor(max) 14.6 mV; 95% CI 10.9-22.2 mV) or the EHC-turbinate (EHC-turb(max) 12.5 mV; 95% CI 10.7-23.0 mV) at the most negative basal potential. Measuring with the LSC-floor at the maximal potential increased the Sw (LSC-floor(max) 8.8 mV, 95% CI 6.0-16.1 mV, p=0.009 vs LSC-floor(5cm)), while measuring with the SHC-floor at a fixed location slightly decreased the Sw (SHC-floor(5cm) 9.8 mV, 95% CI 8.9-20.6 mV, p=0.06 vs SHC-floor(max)). In patients with cystic fibrosis, the S(w) was comparable, between 2.2 mV and 4.3 mV. Sample size calculations for trials using NPD to assess changes in ion transport showed that the number of subjects to be included could be approximately halved measuring with the larger surface catheter at a fixed location vs SHC or EHC at fixed locations. CONCLUSION Measuring the NPD at a fixed location and over a larger surface resulted in increased repeatability and thereby also power as a biomarker of CFTR modulation.
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Affiliation(s)
- François Vermeulen
- CF Center, Department of Pediatrics, University Hospital of Leuven, Leuven, Belgium.
| | - Marijke Proesmans
- CF Center, Department of Pediatrics, University Hospital of Leuven, Leuven, Belgium
| | - Mieke Boon
- CF Center, Department of Pediatrics, University Hospital of Leuven, Leuven, Belgium
| | - Kris De Boeck
- CF Center, Department of Pediatrics, University Hospital of Leuven, Leuven, Belgium
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Keenan K, Avolio J, Rueckes-Nilges C, Tullis E, Gonska T, Naehrlich L. Nasal potential difference: Best or average result for CFTR function as diagnostic criteria for cystic fibrosis? J Cyst Fibros 2014; 14:310-6. [PMID: 25300456 DOI: 10.1016/j.jcf.2014.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 12/23/2022]
Abstract
BACKGROUND The current practice of averaging the nasal potential difference (NPD) results of right and left nostril measurements reduce inter-individual variability but may underestimate individual CFTR function. METHODS Best NPD response to Cl(-)-free and isoproterenol perfusion (=largest ΔPD(0Cl/Iso)) from the right and left nostril was compared to the average result in 13 cystic fibrosis (CF), 78 query-CF patients and 22 healthy controls from 2 cohorts. RESULTS Despite moderate to good correlation (p<0.001) between right and left measured ΔPD(0Cl/Iso), we observed large differences in some individuals. A comparison of average versus best ΔPD(0Cl/Iso) showed only moderate agreement (Giessen κ=0.538; Toronto κ=0.607). Averaging ΔPD(0Cl/Iso) showed a lower composite chloride response compared to best ΔPD(0Cl/Iso) and altered diagnostic NPD interpretation in 30 of 113 (27%) subjects. CONCLUSIONS The current practice of averaging the NPD results of right and left nostril measurements leads to an underestimation of the individual CFTR function and should be reconsidered.
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Affiliation(s)
- Katherine Keenan
- Division of Paediatric Gastroenterology, Hepatology and Nutrition, University of Toronto and Physiology and Experimental Medicine, Research Institute, the Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Julie Avolio
- Division of Paediatric Gastroenterology, Hepatology and Nutrition, University of Toronto and Physiology and Experimental Medicine, Research Institute, the Hospital for Sick Children, Toronto, Ontario, Canada.
| | | | - Elizabeth Tullis
- Department of Medicine, University of Toronto and Division of Respirology and Keenan Research Centre of Li Ka Shing Knowledge Institute St. Michael's Hospital, Toronto, Ontario, Canada.
| | - Tanja Gonska
- Division of Paediatric Gastroenterology, Hepatology and Nutrition, University of Toronto and Physiology and Experimental Medicine, Research Institute, the Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Lutz Naehrlich
- Department of Pediatrics, Justus-Liebig-University Giessen, Giessen, Germany.
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Rowe SM, Reeves G, Hathorne H, Solomon GM, Abbi S, Renard D, Lock R, Zhou P, Danahay H, Clancy JP, Waltz DA. Reduced sodium transport with nasal administration of the prostasin inhibitor camostat in subjects with cystic fibrosis. Chest 2013; 144:200-207. [PMID: 23412700 DOI: 10.1378/chest.12-2431] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Prostasin, a trypsin-like serine protease, is a channel-activating protease and major regulator of epithelial sodium channel-mediated sodium absorption. Its direct inhibition by camostat represents a potential approach to inhibiting sodium transport in cystic fibrosis (CF). METHODS To determine whether a topical formulation of camostat represents an efficacious and tolerable approach to reducing Na+ transport in the CF airway, we conducted a two-part randomized, double-blind, placebo-controlled, crossover, ascending single-dose study to evaluate the pharmacodynamics, safety, and pharmacokinetics of camostat administered through a nasal spray pump in subjects with CF. Nasal potential difference (PD) was measured before and after treatment, and safety and pharmacokinetics were assessed by a standardized approach. RESULTS In part 1, nine subjects were enrolled, and six completed crossover dosing at the maximally tolerated dose. The change in maximal (most polarizing) basal PD 2 h following administration of camostat was +13.1 mV (1.6-mg dose group) compared with -8.6 mV following placebo (P<.005). Intrasubject change in Ringer and amiloride-sensitive PDs exhibited similar and consistent responses. Bayesian analysis in an additional six subjects in part 2 estimated a dose of 18 μg/mL to provide 50% of the maximum effect. There was no significant change in chloride transport or total nasal symptom score, nasal examination rating, and laboratory parameters. CONCLUSIONS This study establishes the proof of concept that a reduction in sodium transport in the human CF airway can be achieved through inhibition of prostasin activity, identifying a potential therapeutic target in the disease. TRIAL REGISTRATION ClinicalTrials.gov; No.: NCT00506792; URL: www.clinicaltrials.gov.
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Affiliation(s)
- Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL; Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL; Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, AL; Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL.
| | - Ginger Reeves
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL; Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Heather Hathorne
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL; Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - G Martin Solomon
- Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Smita Abbi
- Novartis Institutes for BioMedical Research, East Hanover, NJ
| | - Didier Renard
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Ruth Lock
- Novartis Institutes for BioMedical Research, Horsham, England
| | - Ping Zhou
- Novartis Institutes for BioMedical Research, Horsham, England
| | - Henry Danahay
- Novartis Institutes for BioMedical Research, Horsham, England
| | - John P Clancy
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, and University of Cincinnati, Cincinnati, OH
| | - David A Waltz
- Novartis Institutes for BioMedical Research, Cambridge, MA
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O'Reilly R, Elphick HE. Development, clinical utility, and place of ivacaftor in the treatment of cystic fibrosis. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:929-37. [PMID: 24039402 PMCID: PMC3770629 DOI: 10.2147/dddt.s30345] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Cystic fibrosis (CF) is a life-limiting, multisystem disease characterized by thick viscous secretions leading to recurrent lung infections, bronchiectasis, and progressive deterioration in lung function. CF is caused by loss or dysfunction of the CF transmembrane conductance regulator (CFTR) protein which is responsible for transepithelial chloride and water transport. Improved understanding of CFTR protein dysfunction has allowed the development of mutation-specific small-molecule compounds which directly target the underlying CFTR defect. Ivacaftor is the first licensed small-molecule compound for CF patients which targets the CFTR gating mutation Gly551Asp (previously termed G551D) and has the potential to be truly disease-modifying. Ivacaftor is an oral medication given twice daily and has shown benefit in terms of an increase in lung function, decreased sweat chloride, weight gain, improvement in patient-reported quality of life, and reduction in number of respiratory exacerbations in clinical trials. Although ivacaftor is currently only licensed for use in approximately 5% of the CF population (those who have at least one Gly551Asp mutation), the developmental pathway established by ivacaftor paves the way for other CFTR modulators that may benefit many more patients. In particular, a CFTR modulator for those with the Phe508del deletion (previously ∆F508) would allow 90% of the CF population to benefit from disease-modifying treatment.
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Affiliation(s)
- Ruth O'Reilly
- Sheffield Children's Hospital, Western Bank, Sheffield, United Kingdom
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Koukuntla R, Ramsey WJ, Young WB, Link CJ. U6 promoter-enhanced GlnUAG suppressor tRNA has higher suppression efficacy and can be stably expressed in 293 cells. J Gene Med 2013; 15:93-101. [PMID: 23303531 DOI: 10.1002/jgm.2696] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 11/17/2012] [Accepted: 01/02/2013] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Almost one-third of all human genetic diseases are the result of nonsense mutations that can result in truncated proteins. Nonsense suppressor tRNAs (NSTs) were proposed as valuable tools for gene therapy of genetic diseases caused by premature termination codons (PTCs). Although various strategies have been adapted aiming to increase NST expression and efficacy, low suppression efficacies of NSTs and toxicity associated with stable expression of suppressor tRNAs have hampered the development of NST-mediated gene therapy. METHODS We have employed the U6 promoter to enhance Gln-Amber suppressor tRNA (GlnUAG) expression and to increase PTC suppression in mammalian cells. In an attempt to study the toxic effects of NSTs, a stable 293 cell line constitutively expressing a U6 promoter-enhanced GlnUAG tRNA was established. To examine whether any proteomic changes occurred in cells that constitutively express suppressor tRNA, whole cell proteins from cells with and without any suppressor tRNA expression were analyzed. RESULTS The data obtained suggest that U6 promoter-enhanced GlnUAG tRNAs have higher suppression efficacies than multimers of the same suppressor tRNA without a U6 promoter. Proteomic analysis of cells constitutively expressing the GlnUAG suppressor tRNA indicates that stable expression of NSTs may not lead to significant read through of normal cellular proteins. CONCLUSIONS Because most tRNAs have cell-specific differential expression, this technique will enable the expression of different kinds of suppressor tRNAs in various cell types at high, functionally relevant levels. The techniques developed in the present study may contribute to the further development of suppressor tRNA-mediated gene therapy.
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Affiliation(s)
- Ramesh Koukuntla
- Genetics, Cellular and Developmental Biology, Iowa State University, Ames, IA, USA
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Rowe SM, Liu B, Hill A, Hathorne H, Cohen M, Beamer JR, Accurso FJ, Dong Q, Ordoñez CL, Stone AJ, Olson ER, Clancy JP. Optimizing nasal potential difference analysis for CFTR modulator development: assessment of ivacaftor in CF subjects with the G551D-CFTR mutation. PLoS One 2013; 8:e66955. [PMID: 23922647 PMCID: PMC3724869 DOI: 10.1371/journal.pone.0066955] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 05/13/2013] [Indexed: 11/18/2022] Open
Abstract
Nasal potential difference (NPD) is used as a biomarker of the cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC) activity. We evaluated methods to detect changes in chloride and sodium transport by NPD based on a secondary analysis of a Phase II CFTR-modulator study. Thirty-nine subjects with CF who also had the G551D-CFTR mutation were randomized to receive ivacaftor (Kalydeco™; also known as VX-770) in four doses or placebo twice daily for at least 14 days. All data were analyzed by a single investigator who was blinded to treatment assignment. We compared three analysis methods to determine the best approach to quantify changes in chloride and sodium transport: (1) the average of both nostrils; (2) the most-polarized nostril at each visit; and (3) the most-polarized nostril at screening carried forward. Parameters of ion transport included the PD change with zero chloride plus isoproterenol (CFTR activity), the basal PD, Ringer's PD, and change in PD with amiloride (measurements of ENaC activity), and the delta NPD (measuring CFTR and ENaC activity). The average and most-polarized nostril at each visit were most sensitive to changes in chloride and sodium transport, whereas the most-polarized nostril at screening carried forward was less discriminatory. Based on our findings, NPD studies should assess both nostrils rather than a single nostril. We also found that changes in CFTR activity were more readily detected than changes in ENaC activity, and that rigorous standardization was associated with relatively good within-subject reproducibility in placebo-treated subjects (±2.8 mV). Therefore, we have confirmed an assay of reasonable reproducibility for detecting chloride-transport improvements in response to CFTR modulation.
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Affiliation(s)
- Steven M. Rowe
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Bo Liu
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Aubrey Hill
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Heather Hathorne
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Morty Cohen
- Seattle Children's Hospital, Seattle, Washington, United States of America
| | - John R. Beamer
- Seattle Children's Hospital, Seattle, Washington, United States of America
| | - Frank J. Accurso
- University of Colorado Denver, Aurora, Colorado, United States of America
| | - Qunming Dong
- Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts, United States of America
| | - Claudia L. Ordoñez
- Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts, United States of America
| | - Anne J. Stone
- Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts, United States of America
| | - Eric R. Olson
- Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts, United States of America
| | - John P. Clancy
- Cincinnati Children's Hospital Medical Center and the University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail:
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Fajac I, Sermet-Gaudelus I. Mucoviscidose : nouvelles thérapeutiques ciblant la protéine CFTR. Rev Mal Respir 2013; 30:255-61. [DOI: 10.1016/j.rmr.2012.10.631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 10/23/2012] [Indexed: 12/01/2022]
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Altamura N, Castaldo R, Finotti A, Breveglieri G, Salvatori F, Zuccato C, Gambari R, Panin GC, Borgatti M. Tobramycin is a suppressor of premature termination codons. J Cyst Fibros 2013; 12:806-11. [PMID: 23540394 DOI: 10.1016/j.jcf.2013.02.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 02/04/2013] [Accepted: 02/24/2013] [Indexed: 11/19/2022]
Abstract
Premature translation terminations (PTCs) constitute the molecular basis of many genetic diseases, including cystic fibrosis, as they lead to the synthesis of truncated non-functional or partially functional protein. Suppression of translation terminations at PTCs (read-through) has been developed as a therapeutic strategy to restore full-length protein in several genetic diseases. Phenotypic consequences of PTCs can be exacerbated by the nonsense-mediated mRNA decay (NMD) pathway that detects and degrades mRNA containing PTC. Modulation of NMD, therefore, is also of interest as a potential target for the suppression therapy. Tobramycin is an aminoglycoside antibiotic, normally used to treat Pseudomonas aeruginosa pulmonary infection in CF patients. In the present study, by using yeast as a genetic system, we have examined the ability of Tobramycin to suppress PTCs as a function of the presence or absence of NMD. Results demonstrate that Tobramycin exhibits read-through ability on PTCs and preferentially in absence of NMD.
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Affiliation(s)
- Nicola Altamura
- Institute of Biomembranes and Bioenergetics, CNR, Via Amendola 165/A, 70126 Bari, Italy.
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Leonard A, Leal T, Lebecque P. [Mucoviscidosis: CFTR mutation-specific therapy: a ray of sunshine in a cloudy sky]. Arch Pediatr 2012. [PMID: 23199563 DOI: 10.1016/j.arcped.2012.10.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
There is a need to find a cure for pulmonary disease in cystic fibrosis (CF), though full benefit of this approach will be restricted to those patients with well-preserved lungs. The most promising route is currently that of a pharmacological mutation-specific approach aiming at correcting the mechanism by which mutations lead to impairment of chloride conductance across respiratory epithelial cells. In the past 14years, 7 candidate drugs (CPX, 4PBA, gentamicin, PTC124, VX-770 or Ivacaftor, VX-809 or Lumacaftor, and Miglustat) have been investigated in CF patients. A postulate of 14 out of the 15 published studies has been that an effective agent had to improve total chloride secretion as assessed in vivo by nasal potential difference measurements. The present review casts a critical look at these studies. Apparent inconsistencies are discussed as well as possible limitations of nasal potential difference measurements as outcome parameters in these trials. Primarily targeting a mutation carried by less than 2% of French CF patients, the 2 Ivacaftor studies could well be a milestone on the long road toward a cure for CF. However, further data on safety and long-term efficacy are obviously needed and the current price of this medication in the US would make it unaffordable for European patients.
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Affiliation(s)
- A Leonard
- Unité de pneumologie pédiatrique et mucoviscidose, cliniques Saint-Luc, université de Louvain, Bruxelles, Belgique.
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Abstract
Cystic Fibrosis (CF) is caused by a large number of mutations in the CFTR gene, leading to specific classes of protein defects. This review discusses these classes, an understanding of which has paved the way for novel treatment strategies. The progress in this field, through from basic research to, in one case, application for license, is described.
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Affiliation(s)
- Rebecca M Thursfield
- National Heart and Lung Institute, Imperial College, Manresa Road, London, SW3 6LR.
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Bordeira-Carriço R, Pêgo AP, Santos M, Oliveira C. Cancer syndromes and therapy by stop-codon readthrough. Trends Mol Med 2012; 18:667-78. [PMID: 23044248 DOI: 10.1016/j.molmed.2012.09.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Revised: 08/10/2012] [Accepted: 09/17/2012] [Indexed: 12/19/2022]
Abstract
Several hereditary cancer syndromes are associated with nonsense mutations that create premature termination codons (PTC). Therapeutic strategies involving readthrough induction partially restore expression of proteins with normal function from nonsense-mutated genes, and small molecules such as aminoglycosides and PTC124 have exhibited promising results for treating patients with cystic fibrosis and Duchenne muscular dystrophy. Transgenic expression of suppressor-tRNAs and depleting translation termination factors are, among others, potential strategies for treating PTC-associated diseases. In this review, the potential of using readthrough strategies as a therapy for cancer syndromes is discussed, and we consider the effect of nonsense-mediated decay and other factors on readthrough efficiency.
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Rowe SM, Borowitz DS, Burns JL, Clancy JP, Donaldson SH, Retsch-Bogart G, Sagel SD, Ramsey BW. Progress in cystic fibrosis and the CF Therapeutics Development Network. Thorax 2012; 67:882-90. [PMID: 22960984 PMCID: PMC3787701 DOI: 10.1136/thoraxjnl-2012-202550] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cystic fibrosis (CF), the most common life-shortening genetic disorder in Caucasians, affects approximately 70 000 individuals worldwide. In 1998, the Cystic Fibrosis Foundation (CFF) launched the CF Therapeutics Development Network (CF-TDN) as a central element of its Therapeutics Development Programme. Designed to accelerate the clinical evaluation of new therapies needed to fulfil the CFF mission to control and cure CF, the CF-TDN has conducted 75 clinical trials since its inception, and has contributed to studies as varied as initial safety and proof of concept trials to pivotal programmes required for regulatory approval. This review highlights recent and significant research efforts of the CF-TDN, including a summary of contributions to studies involving CF transmembrane conductance regulator (CFTR) modulators, airway surface liquid hydrators and mucus modifiers, anti-infectives, anti-inflammatories, and nutritional therapies. Efforts to advance CF biomarkers, necessary to accelerate the therapeutic goals of the network, are also summarised.
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Affiliation(s)
- Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, 1819 University Boulevard (MCLM 768), Birmingham, AL 35294, USA.
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Keeling KM, Wang D, Conard SE, Bedwell DM. Suppression of premature termination codons as a therapeutic approach. Crit Rev Biochem Mol Biol 2012; 47:444-63. [PMID: 22672057 PMCID: PMC3432268 DOI: 10.3109/10409238.2012.694846] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In this review, we describe our current understanding of translation termination and pharmacological agents that influence the accuracy of this process. A number of drugs have been identified that induce suppression of translation termination at in-frame premature termination codons (PTCs; also known as nonsense mutations) in mammalian cells. We discuss efforts to utilize these drugs to suppress disease-causing PTCs that result in the loss of protein expression and function. In-frame PTCs represent a genotypic subset of mutations that make up ~11% of all known mutations that cause genetic diseases, and millions of patients have diseases attributable to PTCs. Current approaches aimed at reducing the efficiency of translation termination at PTCs (referred to as PTC suppression therapy) have the goal of alleviating the phenotypic consequences of a wide range of genetic diseases. Suppression therapy is currently in clinical trials for treatment of several genetic diseases caused by PTCs, and preliminary results suggest that some patients have shown clinical improvements. While current progress is promising, we discuss various approaches that may further enhance the efficiency of this novel therapeutic approach.
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Affiliation(s)
- Kim M. Keeling
- Dept. of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dan Wang
- Dept. of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sara E. Conard
- Dept. of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David M. Bedwell
- Dept. of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
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Cystic fibrosis: insight into CFTR pathophysiology and pharmacotherapy. Clin Biochem 2012; 45:1132-44. [PMID: 22698459 DOI: 10.1016/j.clinbiochem.2012.05.034] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 05/15/2012] [Accepted: 05/28/2012] [Indexed: 12/14/2022]
Abstract
Cystic fibrosis is the most common life-threatening recessively inherited disease in Caucasians. Due to early provision of care in specialized reference centers and more comprehensive care, survival has improved over time. Despite great advances in supportive care and in our understanding of its pathophysiology, there is still no cure for the disease. Therapeutic strategies aimed at rescuing the abnormal protein are either being sought after or under investigation. This review highlights salient insights into pathophysiology and candidate molecules suitable for CFTR pharmacotherapy. Clinical trials using Ataluren, VX-809 and ivacaftor have provided encouraging data. Preclinical data with inhibitors of phosphodiesterase type 5, such as sildenafil and analogs, have highlighted their potential for CFTR pharmacotherapy. Because sildenafil and analogs are in clinical use for other clinical applications, research on this class of drugs might speed up the development of new therapies for CF.
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Leonard A, Lebecque P, Dingemanse J, Leal T. A randomized placebo-controlled trial of miglustat in cystic fibrosis based on nasal potential difference. J Cyst Fibros 2012; 11:231-6. [PMID: 22281182 DOI: 10.1016/j.jcf.2011.12.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 12/16/2011] [Accepted: 12/17/2011] [Indexed: 10/14/2022]
Abstract
BACKGROUND Preclinical data suggest that miglustat could restore the function of the cystic fibrosis transmembrane conductance regulator gene in cystic fibrosis cells. METHODS Single-center, randomized, double-blind, placebo-controlled, crossover Phase II study in 11 patients (mean±SD age, 26.3±7.7 years) homozygous for the F508del mutation received oral miglustat 200 mgt.i.d. or placebo for two 8-day cycles separated by a 14-day washout period. The primary endpoint was the change in total chloride secretion (TCS) assessed by nasal potential difference. RESULTS No statistically significant changes in TCS, sweat chloride values or FEV(1) were detected. Pharmacokinetic and safety were similar to those observed in patients with other diseases exposed to miglustat. CONCLUSIONS There was no evidence of a treatment effect on any nasal potential difference variable. Further studies with miglustat need to adequately address criteria for assessment of nasal potential difference.
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Affiliation(s)
- Anissa Leonard
- Pediatric Pulmonology & Cystic Fibrosis Unit, Cliniques St Luc, Université catholique de Louvain, 10 Avenue Hippocrate, 1200 Brussels, Belgium.
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Leonard A, Lubamba B, Dhooghe B, Noel S, Wallemacq P, Lebecque P, Leal T. Comparative Variability of Nasal Potential Difference Measurements in Human and Mice. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ojrd.2012.22007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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CFTR expression analysis in human nasal epithelial cells by flow cytometry. PLoS One 2011; 6:e27658. [PMID: 22163268 PMCID: PMC3233544 DOI: 10.1371/journal.pone.0027658] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 10/21/2011] [Indexed: 01/08/2023] Open
Abstract
Rationale Unbiased approaches that study aberrant protein expression in primary airway epithelial cells at single cell level may profoundly improve diagnosis and understanding of airway diseases. We here present a flow cytometric procedure to study CFTR expression in human primary nasal epithelial cells from patients with Cystic Fibrosis (CF). Our novel approach may be important in monitoring of therapeutic responses, and better understanding of CF disease at the molecular level. Objectives Validation of a panel of CFTR-directed monoclonal antibodies for flow cytometry and CFTR expression analysis in nasal epithelial cells from healthy controls and CF patients. Methods We analyzed CFTR expression in primary nasal epithelial cells at single cell level using flow cytometry. Nasal cells were stained for pan-Cytokeratin, E cadherin, and CD45 (to discriminate epithelial cells and leukocytes) in combination with intracellular staining of CFTR. Healthy individuals and CF patients were compared. Measurements and Main Results We observed various cellular populations present in nasal brushings that expressed CFTR protein at different levels. Our data indicated that CF patients homozygous for F508del express varying levels of CFTR protein in nasal epithelial cells, although at a lower level than healthy controls. Conclusion CFTR protein is expressed in CF patients harboring F508del mutations but at lower levels than in healthy controls. Multicolor flow cytometry of nasal cells is a relatively simple procedure to analyze the composition of cellular subpopulations and protein expression at single cell level.
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Rogan MP, Stoltz DA, Hornick DB. Cystic fibrosis transmembrane conductance regulator intracellular processing, trafficking, and opportunities for mutation-specific treatment. Chest 2011; 139:1480-1490. [PMID: 21652558 DOI: 10.1378/chest.10-2077] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Recent advances in basic science have greatly expanded our understanding of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR), the chloride and bicarbonate channel that is encoded by the gene, which is mutated in patients with CF. We review the structure, function, biosynthetic processing, and intracellular trafficking of CFTR and discuss the five classes of mutations and their impact on the CF phenotype. The therapeutic discussion is focused on the significant progress toward CFTR mutation-specific therapies. We review the results of encouraging clinical trials examining orally administered therapeutics, including agents that promote read-through of class I mutations (premature termination codons); correctors, which overcome the CFTR misfolding that characterizes the common class II mutation F508del; and potentiators, which enhance the function of class III or IV mutated CFTR at the plasma membrane. Long-term outcomes from successful mutation-specific treatments could finally answer the question that has been lingering since and even before the CFTR gene discovery: Will therapies that specifically restore CFTR-mediated chloride secretion slow or arrest the deleterious cascade of events leading to chronic infection, bronchiectasis, and end-stage lung disease?
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Affiliation(s)
- Mark P Rogan
- Department of Respiratory Medicine, Waterford Regional Hospital, Waterford, Ireland
| | - David A Stoltz
- Department of Internal Medicine, Division of Pulmonary, Critical Care, and Occupational Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA
| | - Douglas B Hornick
- Department of Internal Medicine, Division of Pulmonary, Critical Care, and Occupational Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA.
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Rowe SM, Sloane P, Tang LP, Backer K, Mazur M, Buckley-Lanier J, Nudelman I, Belakhov V, Bebok Z, Schwiebert E, Baasov T, Bedwell DM. Suppression of CFTR premature termination codons and rescue of CFTR protein and function by the synthetic aminoglycoside NB54. J Mol Med (Berl) 2011; 89:1149-61. [PMID: 21779978 DOI: 10.1007/s00109-011-0787-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 05/18/2011] [Accepted: 06/23/2011] [Indexed: 01/28/2023]
Abstract
Certain aminoglycosides are capable of inducing "translational readthrough" of premature termination codons (PTCs). However, toxicity and relative lack of efficacy deter treatment with clinically available aminoglycosides for genetic diseases caused by PTCs, including cystic fibrosis (CF). Using a structure-based approach, the novel aminoglycoside NB54 was developed that exhibits reduced toxicity and enhanced suppression of PTCs in cell-based reporter assays relative to gentamicin. We examined whether NB54 administration rescued CFTR protein and function in clinically relevant CF models. In a fluorescence-based halide efflux assay, NB54 partially restored halide efflux in a CF bronchial epithelial cell line (CFTR genotype W1282X/F508del), but not in a CF epithelial cell line lacking a PTC (F508del/F508del). In polarized airway epithelial cells expressing either a CFTR-W1282X or -G542X cDNA, treatment with NB54 increased stimulated short-circuit current (I (SC)) with greater efficiency than gentamicin. NB54 and gentamicin induced comparable increases in forskolin-stimulated I (SC) in primary airway epithelial cells derived from a G542X/F508del CF donor. Systemic administration of NB54 to Cftr-/- mice expressing a human CFTR-G542X transgene restored 15-17% of the average stimulated transepithelial chloride currents observed in wild-type (Cftr+/+) mice, comparable to gentamicin. NB54 exhibited reduced cellular toxicity in vitro and was tolerated at higher concentrations than gentamicin in vivo. These results provide evidence that synthetic aminoglycosides are capable of PTC suppression in relevant human CF cells and a CF animal model and support further development of these compounds as a treatment modality for genetic diseases caused by PTCs.
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Affiliation(s)
- Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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Keeling KM, Bedwell DM. Suppression of nonsense mutations as a therapeutic approach to treat genetic diseases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:837-52. [PMID: 21976286 DOI: 10.1002/wrna.95] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Suppression therapy is a treatment strategy for genetic diseases caused by nonsense mutations. This therapeutic approach utilizes pharmacological agents that suppress translation termination at in-frame premature termination codons (PTCs) to restore translation of a full-length, functional polypeptide. The efficiency of various classes of compounds to suppress PTCs in mammalian cells is discussed along with the current limitations of this therapy. We also elaborate on approaches to improve the efficiency of suppression that include methods to enhance the effectiveness of current suppression drugs and the design or discovery of new, more effective suppression agents. Finally, we discuss the role of nonsense-mediated mRNA decay (NMD) in limiting the effectiveness of suppression therapy, and describe tactics that may allow the efficiency of NMD to be modulated in order to enhance suppression therapy.
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Affiliation(s)
- Kim M Keeling
- Department of Microbiology, Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
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Rüegg MA, Glass DJ. Molecular mechanisms and treatment options for muscle wasting diseases. Annu Rev Pharmacol Toxicol 2011; 51:373-95. [PMID: 20936944 DOI: 10.1146/annurev-pharmtox-010510-100537] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Loss of muscle mass can be the consequence of pathological changes, as observed in muscular dystrophies; or it can be secondary to cachexia-inducing diseases that cause muscle atrophy, such as cancer, heart disease, or chronic obstructive pulmonary disease; or it can be a consequence of aging or simple disuse. Although muscular dystrophies are rare, muscle loss affects millions of people worldwide. We discuss the molecular mechanisms involved in muscular dystrophy and in muscle atrophy and present current strategies aimed at ameliorating these diseases. Finally, we discuss whether lessons learned from studying muscular dystrophies will also be helpful for halting muscle loss secondary to nondystrophic diseases and whether strategies to halt muscle atrophy have potential for the treatment of muscular dystrophies.
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46
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Rowe SM, Clancy JP, Wilschanski M. Nasal potential difference measurements to assess CFTR ion channel activity. Methods Mol Biol 2011; 741:69-86. [PMID: 21594779 DOI: 10.1007/978-1-61779-117-8_6] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Nasal potential difference measurement is used to measure the voltage across the nasal epithelium, which results from transepithelial ion transport and reflects in part CFTR function. The electrophysiologic abnormality in cystic fibrosis was first described 30 years ago and correlates with features of the CF phenotype. NPD measurement is an important in vivo research and diagnostic tool, and is used to assess the efficacy of new treatments such as gene therapy and ion transport modulators. This chapter will elaborate on the electrophysiological principles behind the test, the equipment required, the methods, and the analysis of the data.
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Affiliation(s)
- Steven M Rowe
- Department of Medicine, University of Alabama, Birmingham, AL 35294-0006, USA.
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Hug MJ, Derichs N, Bronsveld I, Clancy JP. Measurement of ion transport function in rectal biopsies. Methods Mol Biol 2011; 741:87-107. [PMID: 21594780 DOI: 10.1007/978-1-61779-117-8_7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Cystic fibrosis (CF) is caused by mutations in the gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR functions as an anion channel and is known to interact with a number of other cellular proteins involved in ion transport. To date more than 1,800 mutations are known, most of which result in various degrees of impaired transport function of the gene product. Due to the high inter-individual variability of disease onset and progression, CF still is a diagnostic challenge. Implemented almost 20 years ago, the measurement of electrolyte transport function of rectal biopsies is a useful ex vivo tool to diagnose CF. In this chapter we will review the different approaches to perform ion transport measurements and try to highlight the advantages and limitations of these techniques.
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Affiliation(s)
- Martin J Hug
- Pharmacy, University Medical Center Freiburg, D-79106, Freiburg, Germany.
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Abstract
The report of the first CF patients to receive CFTR gene therapy appeared in 1993; since then, there have been over 20 clinical trials of both viral and non-viral gene transfer agents. These have largely been single dose to either nose or lower airway and have been designed around molecular or bioelectrical outcome measures. Both transgene mRNA and partial correction of chloride secretion have been reported, although sodium hyperabsorption has not been improved. The UK CF Gene Therapy Consortium is focussed on a clinical programme to establish whether these proof-of-principle measures translate into clinical benefit. Here, we discuss the considerations in designing such a programme, focusing in particular on our choice of the optimal, currently available delivery method and established and novel outcome measures. We highlight the logistic and regulatory complexities of such a clinical programme and finally, we look to the future and consider possible alternative strategies.
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Affiliation(s)
- Jane C Davies
- Department of Gene Therapy, Imperial College London, SW3 6LR, London, UK.
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Collawn JF, Fu L, Bebok Z. Targets for cystic fibrosis therapy: proteomic analysis and correction of mutant cystic fibrosis transmembrane conductance regulator. Expert Rev Proteomics 2010; 7:495-506. [PMID: 20653506 DOI: 10.1586/epr.10.45] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Proteomic analysis has proved to be an important tool for understanding the complex nature of genetic disorders, such as cystic fibrosis (CF), by defining the cellular protein environment (proteome) associated with wild-type and mutant proteins. Proteomic screens identified the proteome of CF transmembrane conductance regulator (CFTR), and provided fundamental information to studies designed for understanding the crucial components of physiological CFTR function. Simultaneously, high-throughput screens for small-molecular correctors of CFTR mutants provided promising candidates for therapy. The majority of CF cases are caused by nucleotide deletions (DeltaF508 CFTR; >75%), resulting in CFTR misfolding, or insertion of premature termination codons ( approximately 10%), leading to unstable mRNA and reduced levels of truncated dysfunctional CFTR. In this article, we review recent results of proteomic screens, developments in identifying correctors for the most frequent CFTR mutants, and comment on how integration of the knowledge gained from these studies may aid in finding a cure for CF and a number of other genetic disorders.
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Affiliation(s)
- James F Collawn
- University of Alabama at Birmingham, Department of Cell Biology, Birmingham, AL, USA.
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Simon AJ, Lev A, Wolach B, Gavrieli R, Amariglio N, Rosenthal E, Gazit E, Eyal E, Rechavi G, Somech R. The effect of gentamicin-induced readthrough on a novel premature termination codon of CD18 leukocyte adhesion deficiency patients. PLoS One 2010; 5:e13659. [PMID: 21103413 PMCID: PMC2982813 DOI: 10.1371/journal.pone.0013659] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 09/23/2010] [Indexed: 12/22/2022] Open
Abstract
Background Leukocyte adhesion deficiency 1 (LAD1) is an inherited disorder of neutrophil function. Nonsense mutations in the affected CD18 (ITB2) gene have rarely been described. In other genes containing such mutations, treatments with aminoglycoside types of antibiotics (e.g., gentamicin) were reported to partially correct the premature protein termination, by induction of readthrough mechanism. Methodology/Principal Findings Genetic analysis was performed on 2 LAD1 patients. Expression, functional and immunofluorescence assays of CD18 in the patients were used to determine the in-vivo and in-vitro effects of gentamicin-induced readthrough. A theoretical modeling of the corrected CD18 protein was developed to predict the protein function. Results We found a novel premature termination codon, C562T (R188X), in exon 6 of the CD18 gene that caused a severe LAD1 phenotype in two unrelated Palestinian children. In-vivo studies on these patients' cells after gentamicin treatment showed abnormal adhesion and chemotactic functions, while in-vitro studies showed mislocalization of the corrected protein to the cytoplasm and not to the cell surface. A theoretical modeling of the corrected CD18 protein suggested that the replacement of the wild type arginine by gentamicin induced tryptophan at the position of the nonsense mutation, although enabled the expression of the entire CD18 protein, this was not sufficient to stabilize the CD18/11 heterodimer at the cell surface. Conclusion A novel nonsense mutation in the CD18 gene causing a complete absence of CD18 protein and severe LAD1 clinical phenotype is reported. Both in vivo and in vitro treatments with gentamicin resulted in the expression of a corrected full-length dysfunctional or mislocalized CD18 protein. However, while the use of gentamicin increased the expression of CD18, it did not improve leukocyte adhesion and chemotaxis. Moreover, the integrity of the CD18/CD11 complex at the cell surface was impaired, due to abnormal CD18 protein and possibly lack of CD11a expression.
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Affiliation(s)
- Amos J. Simon
- Cancer Research Center, Chaim Sheba Medical Center, Tel Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Hematology Laboratory, Chaim Sheba Medical Center, Tel Hashomer, Israel
| | - Atar Lev
- Cancer Research Center, Chaim Sheba Medical Center, Tel Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Baruch Wolach
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Laboratory for Leukocyte Function and Department of Pediatrics, Meir Medical Center, Kfar Saba, Israel
| | - Ronit Gavrieli
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Laboratory for Leukocyte Function and Department of Pediatrics, Meir Medical Center, Kfar Saba, Israel
| | - Ninette Amariglio
- Cancer Research Center, Chaim Sheba Medical Center, Tel Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Hematology Laboratory, Chaim Sheba Medical Center, Tel Hashomer, Israel
| | - Ester Rosenthal
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Hematology Laboratory, Chaim Sheba Medical Center, Tel Hashomer, Israel
| | - Ephraim Gazit
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Tissue Typing Laboratory, Chaim Sheba Medical Center, Tel Hashomer, Israel
| | - Eran Eyal
- Cancer Research Center, Chaim Sheba Medical Center, Tel Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gideon Rechavi
- Cancer Research Center, Chaim Sheba Medical Center, Tel Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Raz Somech
- Cancer Research Center, Chaim Sheba Medical Center, Tel Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Immunology Service, Chaim Sheba Medical Center, Edmond and Lily Safra Children's Hospital, Tel Hashomer, Israel
- * E-mail:
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