1
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Han X, Li D, Zhu Y, Schneider-Futschik EK. Recommended Tool Compounds for Modifying the Cystic Fibrosis Transmembrane Conductance Regulator Channel Variants. ACS Pharmacol Transl Sci 2024; 7:933-950. [PMID: 38633590 PMCID: PMC11019735 DOI: 10.1021/acsptsci.3c00362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 04/19/2024]
Abstract
Cystic fibrosis (CF) is a genetic disorder arising from variations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, leading to multiple organ system defects. CFTR tool compounds are molecules that can modify the activity of the CFTR channel. Especially, patients that are currently not able to benefit from approved CFTR modulators, such as patients with rare CFTR variants, benefit from further research in discovering novel tools to modulate CFTR. This Review explores the development and classification of CFTR tool compounds, including CFTR blockers (CFTRinh-172, GlyH-101), potentiators (VRT-532, Genistein), correctors (VRT-325, Corr-4a), and other approved and unapproved modulators, with detailed descriptions and discussions for each compound. The challenges and future directions in targeting rare variants and optimizing drug delivery, and the potential synergistic effects in combination therapies are outlined. CFTR modulation holds promise not only for CF treatment but also for generating CF models that contribute to CF research and potentially treating other diseases such as secretory diarrhea. Therefore, continued research on CFTR tool compounds is critical.
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Affiliation(s)
- XiaoXuan Han
- Department of Biochemistry & Pharmacology,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Danni Li
- Department of Biochemistry & Pharmacology,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Yimin Zhu
- Department of Biochemistry & Pharmacology,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Elena K. Schneider-Futschik
- Department of Biochemistry & Pharmacology,
School of Biomedical Sciences, Faculty of Medicine, Dentistry and
Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
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2
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Yeh HI, Sutcliffe KJ, Sheppard DN, Hwang TC. CFTR Modulators: From Mechanism to Targeted Therapeutics. Handb Exp Pharmacol 2024; 283:219-247. [PMID: 35972584 DOI: 10.1007/164_2022_597] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
People with cystic fibrosis (CF) suffer from a multi-organ disorder caused by loss-of-function variants in the gene encoding the epithelial anion channel cystic fibrosis transmembrane conductance regulator (CFTR). Tremendous progress has been made in both basic and clinical sciences over the past three decades since the identification of the CFTR gene. Over 90% of people with CF now have access to therapies targeting dysfunctional CFTR. This success was made possible by numerous studies in the field that incrementally paved the way for the development of small molecules known as CFTR modulators. The advent of CFTR modulators transformed this life-threatening illness into a treatable disease by directly binding to the CFTR protein and correcting defects induced by pathogenic variants. In this chapter, we trace the trajectory of structural and functional studies that brought CF therapies from bench to bedside, with an emphasis on mechanistic understanding of CFTR modulators.
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Affiliation(s)
- Han-I Yeh
- Department of Pharmacology, National Yang Ming Chiao Tung University, Taipei City, Taiwan
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Katy J Sutcliffe
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Tzyh-Chang Hwang
- Department of Pharmacology, National Yang Ming Chiao Tung University, Taipei City, Taiwan.
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA.
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA.
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3
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Juarez-Navarro K, Ayala-Garcia VM, Ruiz-Baca E, Meneses-Morales I, Rios-Banuelos JL, Lopez-Rodriguez A. Assistance for Folding of Disease-Causing Plasma Membrane Proteins. Biomolecules 2020; 10:biom10050728. [PMID: 32392767 PMCID: PMC7277483 DOI: 10.3390/biom10050728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 04/16/2020] [Accepted: 04/21/2020] [Indexed: 02/06/2023] Open
Abstract
An extensive catalog of plasma membrane (PM) protein mutations related to phenotypic diseases is associated with incorrect protein folding and/or localization. These impairments, in addition to dysfunction, frequently promote protein aggregation, which can be detrimental to cells. Here, we review PM protein processing, from protein synthesis in the endoplasmic reticulum to delivery to the PM, stressing the main repercussions of processing failures and their physiological consequences in pathologies, and we summarize the recent proposed therapeutic strategies to rescue misassembled proteins through different types of chaperones and/or small molecule drugs that safeguard protein quality control and regulate proteostasis.
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4
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Rescue of tight junctional localization of a claudin-16 mutant D97S by antimalarial medicine primaquine in Madin-Darby canine kidney cells. Sci Rep 2019; 9:9647. [PMID: 31273276 PMCID: PMC6609605 DOI: 10.1038/s41598-019-46250-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 06/17/2019] [Indexed: 12/20/2022] Open
Abstract
Magnesium ion (Mg2+) is paracellularly reabsorbed through claudin-16 (CLDN16) in the thick ascending limb (TAL) of Henle's loop in the kidney. Genetic disorders of CLDN16 cause mislocalization of CLDN16, resulting in hypomagnesemia. There is no effective treatment for hypomagnesemia except for magnesium administration. Here, we searched for a novel drug to restore tight junctional localization of a CLDN16 mutant. A D97S mutant, which has a mutation in the first extracellular loop (ECL) of CLDN16, was mainly colocalized with endosome marker, whereas wild-type (WT) CLDN16 was colocalized with ZO-1, an adaptor protein of tight junctions. The protein stability of the D97S mutant was lower than that of WT. The expression level of the D97S mutant was increased by lactacystin, a proteasomal inhibitor. Endocytosis inhibitors increased the tight junctional localization of the D97S mutant. We found that primaquine, an antimalarial agent, increased the protein stability and cell surface localization of the D97S mutant, but the localization of other mutants, which have mutations in the cytosolic domain or second ECL, was not affected. Transepithelial Mg2+ flux was increased by primaquine in D97S mutant-expressing cells. The expression of chaperon proteins, proteasome activity, and lactate dehydrogenase release were decreased by primaquine, and the proportion of viable cells increased. In contrast, these effects were not observed in WT CLDN16-expressing cells. These results suggested that primaquine increases the tight junctional localization of the D97S mutant, resulting in a reduction in ER stress and cellular injury. Primaquine may become an effective treatment drug for selected patients with mutant CLDN16.
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5
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Marinko J, Huang H, Penn WD, Capra JA, Schlebach JP, Sanders CR. Folding and Misfolding of Human Membrane Proteins in Health and Disease: From Single Molecules to Cellular Proteostasis. Chem Rev 2019; 119:5537-5606. [PMID: 30608666 PMCID: PMC6506414 DOI: 10.1021/acs.chemrev.8b00532] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Indexed: 12/13/2022]
Abstract
Advances over the past 25 years have revealed much about how the structural properties of membranes and associated proteins are linked to the thermodynamics and kinetics of membrane protein (MP) folding. At the same time biochemical progress has outlined how cellular proteostasis networks mediate MP folding and manage misfolding in the cell. When combined with results from genomic sequencing, these studies have established paradigms for how MP folding and misfolding are linked to the molecular etiologies of a variety of diseases. This emerging framework has paved the way for the development of a new class of small molecule "pharmacological chaperones" that bind to and stabilize misfolded MP variants, some of which are now in clinical use. In this review, we comprehensively outline current perspectives on the folding and misfolding of integral MPs as well as the mechanisms of cellular MP quality control. Based on these perspectives, we highlight new opportunities for innovations that bridge our molecular understanding of the energetics of MP folding with the nuanced complexity of biological systems. Given the many linkages between MP misfolding and human disease, we also examine some of the exciting opportunities to leverage these advances to address emerging challenges in the development of therapeutics and precision medicine.
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Affiliation(s)
- Justin
T. Marinko
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Wesley D. Penn
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - John A. Capra
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37245, United States
| | - Jonathan P. Schlebach
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
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6
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Carotti M, Marsolier J, Soardi M, Bianchini E, Gomiero C, Fecchio C, Henriques SF, Betto R, Sacchetto R, Richard I, Sandonà D. Repairing folding-defective α-sarcoglycan mutants by CFTR correctors, a potential therapy for limb-girdle muscular dystrophy 2D. Hum Mol Genet 2019; 27:969-984. [PMID: 29351619 PMCID: PMC5886177 DOI: 10.1093/hmg/ddy013] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 12/30/2017] [Indexed: 11/22/2022] Open
Abstract
Limb-girdle muscular dystrophy type 2D (LGMD2D) is a rare autosomal-recessive disease, affecting striated muscle, due to mutation of SGCA, the gene coding for α-sarcoglycan. Nowadays, more than 50 different SGCA missense mutations have been reported. They are supposed to impact folding and trafficking of α-sarcoglycan because the defective polypeptide, although potentially functional, is recognized and disposed of by the quality control of the cell. The secondary reduction of α-sarcoglycan partners, β-, γ- and δ-sarcoglycan, disrupts a key membrane complex that, associated to dystrophin, contributes to assure sarcolemma stability during muscle contraction. The complex deficiency is responsible for muscle wasting and the development of a severe form of dystrophy. Here, we show that the application of small molecules developed to rescue ΔF508-CFTR trafficking, and known as CFTR correctors, also improved the maturation of several α-sarcoglycan mutants that were consequently rescued at the plasma membrane. Remarkably, in myotubes from a patient with LGMD2D, treatment with CFTR correctors induced the proper re-localization of the whole sarcoglycan complex, with a consequent reduction of sarcolemma fragility. Although the mechanism of action of CFTR correctors on defective α-sarcoglycan needs further investigation, this is the first report showing a quantitative and functional recovery of the sarcoglycan-complex in human pathologic samples, upon small molecule treatment. It represents the proof of principle of a pharmacological strategy that acts on the sarcoglycan maturation process and we believe it has a great potential to develop as a cure for most of the patients with LGMD2D.
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Affiliation(s)
- Marcello Carotti
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Justine Marsolier
- Genethon, Evry F-91002, France.,INSERM, U951, INTEGRARE Research Unit, Evry F-91002, France
| | - Michela Soardi
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Elisa Bianchini
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy.,Aptuit, 37135 Verona, Italy
| | - Chiara Gomiero
- Department of Comparative Biomedicine and Food Science, University of Padova, Agripolis, 35020 Legnaro, Padova, Italy
| | - Chiara Fecchio
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Sara F Henriques
- Genethon, Evry F-91002, France.,INSERM, U951, INTEGRARE Research Unit, Evry F-91002, France
| | - Romeo Betto
- Neuroscience Institute (CNR Padova), 35131 Padova, Italy
| | - Roberta Sacchetto
- Department of Comparative Biomedicine and Food Science, University of Padova, Agripolis, 35020 Legnaro, Padova, Italy
| | - Isabelle Richard
- Genethon, Evry F-91002, France.,INSERM, U951, INTEGRARE Research Unit, Evry F-91002, France
| | - Dorianna Sandonà
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
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7
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Tao YX, Conn PM. Pharmacoperones as Novel Therapeutics for Diverse Protein Conformational Diseases. Physiol Rev 2018; 98:697-725. [PMID: 29442594 DOI: 10.1152/physrev.00029.2016] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
After synthesis, proteins are folded into their native conformations aided by molecular chaperones. Dysfunction in folding caused by genetic mutations in numerous genes causes protein conformational diseases. Membrane proteins are more prone to misfolding due to their more intricate folding than soluble proteins. Misfolded proteins are detected by the cellular quality control systems, especially in the endoplasmic reticulum, and proteins may be retained there for eventual degradation by the ubiquitin-proteasome system or through autophagy. Some misfolded proteins aggregate, leading to pathologies in numerous neurological diseases. In vitro, modulating mutant protein folding by altering molecular chaperone expression can ameliorate some misfolding. Some small molecules known as chemical chaperones also correct mutant protein misfolding in vitro and in vivo. However, due to their lack of specificity, their potential as therapeutics is limited. Another class of compounds, known as pharmacological chaperones (pharmacoperones), binds with high specificity to misfolded proteins, either as enzyme substrates or receptor ligands, leading to decreased folding energy barriers and correction of the misfolding. Because many of the misfolded proteins are misrouted but do not have defects in function per se, pharmacoperones have promising potential in advancing to the clinic as therapeutics, since correcting routing may ameliorate the underlying mechanism of disease. This review will comprehensively summarize this exciting area of research, surveying the literature from in vitro studies in cell lines to transgenic animal models and clinical trials in several protein misfolding diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama ; and Departments of Internal Medicine and Cell Biology, Texas Tech University Health Science Center , Lubbock, Texas
| | - P Michael Conn
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama ; and Departments of Internal Medicine and Cell Biology, Texas Tech University Health Science Center , Lubbock, Texas
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8
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Hou ZS, Ulloa-Aguirre A, Tao YX. Pharmacoperone drugs: targeting misfolded proteins causing lysosomal storage-, ion channels-, and G protein-coupled receptors-associated conformational disorders. Expert Rev Clin Pharmacol 2018; 11:611-624. [DOI: 10.1080/17512433.2018.1480367] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Zhi-Shuai Hou
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM) and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City, Mexico
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
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9
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Liu J, Bihler H, Farinha CM, Awatade NT, Romão AM, Mercadante D, Cheng Y, Musisi I, Jantarajit W, Wang Y, Cai Z, Amaral MD, Mense M, Sheppard DN. Partial rescue of F508del-cystic fibrosis transmembrane conductance regulator channel gating with modest improvement of protein processing, but not stability, by a dual-acting small molecule. Br J Pharmacol 2018; 175:1017-1038. [PMID: 29318594 DOI: 10.1111/bph.14141] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 12/08/2017] [Accepted: 12/10/2017] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND AND PURPOSE Rescue of F508del-cystic fibrosis (CF) transmembrane conductance regulator (CFTR), the most common CF mutation, requires small molecules that overcome protein processing, stability and channel gating defects. Here, we investigate F508del-CFTR rescue by CFFT-004, a small molecule designed to independently correct protein processing and channel gating defects. EXPERIMENTAL APPROACH Using CFTR-expressing recombinant cells and CF patient-derived bronchial epithelial cells, we studied CFTR expression by Western blotting and channel gating and stability with the patch-clamp and Ussing chamber techniques. KEY RESULTS Chronic treatment with CFFT-004 improved modestly F508del-CFTR processing, but not its plasma membrane stability. By contrast, CFFT-004 rescued F508del-CFTR channel gating better than C18, an analogue of the clinically used CFTR corrector lumacaftor. Subsequent acute addition of CFFT-004, but not C18, potentiated F508del-CFTR channel gating. However, CFFT-004 was without effect on A561E-CFTR, a CF mutation with a comparable mechanism of CFTR dysfunction as F508del-CFTR. To investigate the mechanism of action of CFFT-004, we used F508del-CFTR revertant mutations. Potentiation by CFFT-004 was unaffected by revertant mutations, but correction was abolished by the revertant mutation G550E. These data suggest that correction, but not potentiation, by CFFT-004 might involve nucleotide-binding domain 1 of CFTR. CONCLUSIONS AND IMPLICATIONS CFFT-004 is a dual-acting small molecule with independent corrector and potentiator activities that partially rescues F508del-CFTR in recombinant cells and native airway epithelia. The limited efficacy and potency of CFFT-004 suggests that combinations of small molecules targeting different defects in F508del-CFTR might be a more effective therapeutic strategy than a single agent.
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Affiliation(s)
- Jia Liu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Hermann Bihler
- Cystic Fibrosis Foundation Therapeutics, Lexington, MA, USA
| | - Carlos M Farinha
- Faculty of Sciences, BioISI - Biosystems and Integrative Sciences Institute, University of Lisboa, Lisboa, Portugal
| | - Nikhil T Awatade
- Faculty of Sciences, BioISI - Biosystems and Integrative Sciences Institute, University of Lisboa, Lisboa, Portugal
| | - Ana M Romão
- Faculty of Sciences, BioISI - Biosystems and Integrative Sciences Institute, University of Lisboa, Lisboa, Portugal
| | | | - Yi Cheng
- Cystic Fibrosis Foundation Therapeutics, Lexington, MA, USA
| | - Isaac Musisi
- Cystic Fibrosis Foundation Therapeutics, Lexington, MA, USA
| | - Walailak Jantarajit
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK.,Center of Calcium and Bone Research and Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Yiting Wang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Zhiwei Cai
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Margarida D Amaral
- Faculty of Sciences, BioISI - Biosystems and Integrative Sciences Institute, University of Lisboa, Lisboa, Portugal
| | - Martin Mense
- Cystic Fibrosis Foundation Therapeutics, Lexington, MA, USA
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
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10
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Pereira DM, Valentão P, Andrade PB. Tuning protein folding in lysosomal storage diseases: the chemistry behind pharmacological chaperones. Chem Sci 2018; 9:1740-1752. [PMID: 29719681 PMCID: PMC5896381 DOI: 10.1039/c7sc04712f] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/10/2018] [Indexed: 12/15/2022] Open
Abstract
Misfolding of proteins is the basis of several proteinopathies. Chemical and pharmacological chaperones are small molecules capable of inducing the correct conformation of proteins, thus being of interest for human therapeutics. The most recent developments in medicinal chemistry and in the drug development of pharmacological chaperones are discussed, with focus on lysosomal storage diseases.
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Affiliation(s)
- David M Pereira
- REQUIMTE/LAQV , Laboratório de Farmacognosia , Departamento de Química , Faculdade de Farmácia , Universidade do Porto , Rua de Jorge Viterbo Ferreira 228 , 4050-313 Porto , Portugal .
| | - Patrícia Valentão
- REQUIMTE/LAQV , Laboratório de Farmacognosia , Departamento de Química , Faculdade de Farmácia , Universidade do Porto , Rua de Jorge Viterbo Ferreira 228 , 4050-313 Porto , Portugal .
| | - Paula B Andrade
- REQUIMTE/LAQV , Laboratório de Farmacognosia , Departamento de Química , Faculdade de Farmácia , Universidade do Porto , Rua de Jorge Viterbo Ferreira 228 , 4050-313 Porto , Portugal .
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11
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Calvez ML, Benz N, Huguet F, Saint-Pierre A, Rouillé E, Coraux C, Férec C, Kerbiriou M, Trouvé P. Buserelin alleviates chloride transport defect in human cystic fibrosis nasal epithelial cells. PLoS One 2017; 12:e0187774. [PMID: 29145426 PMCID: PMC5690610 DOI: 10.1371/journal.pone.0187774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/25/2017] [Indexed: 11/18/2022] Open
Abstract
Cystic fibrosis (CF) is the most common autosomal recessive disease in Caucasians caused by mutations in the gene encoding the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) chloride (Cl-) channel regulated by protein kinases, phosphatases, divalent cations and by protein-protein interactions. Among protein-protein interactions, we previously showed that Annexin A5 (AnxA5) binds to CFTR and is involved in the channel localization within membranes and in its Cl- channel function. The deletion of phenylalanine at position 508 (F508del) is the most common mutation in CF which leads to an altered protein (F508del-CFTR) folding with a nascent protein retained within the ER and is quickly degraded. We previously showed that AnxA5 binds to F508del-CFTR and that its increased expression due to a Gonadoliberin (GnRH) augments Cl- efflux in cells expressing F508del-CFTR. The aim of the present work was to use the GnRH analog buserelin which is already used in medicine. Human nasal epithelial cells from controls and CF patients (F508del/F508del) were treated with buserelin and we show here that the treatment alleviates Cl- channel defects in CF cells. Using proteomics we highlighted some proteins explaining this result. Finally, we propose that buserelin is a potential new pharmaceutical compound that can be used in CF and that bronchus can be targeted since we show here that they express GnRH-R.
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Affiliation(s)
- Marie-Laure Calvez
- Inserm, UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies", Univ Brest, EFS, IBSAM, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
- Association G Saleun, Brest, France
| | - Nathalie Benz
- Inserm, UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies", Univ Brest, EFS, IBSAM, Brest, France
- Association G Saleun, Brest, France
| | - Florentin Huguet
- Inserm, UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies", Univ Brest, EFS, IBSAM, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
- Association G Saleun, Brest, France
| | - Aude Saint-Pierre
- Inserm, UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies", Univ Brest, EFS, IBSAM, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
| | - Elise Rouillé
- Inserm, UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies", Univ Brest, EFS, IBSAM, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
| | | | - Claude Férec
- Inserm, UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies", Univ Brest, EFS, IBSAM, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
- CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
- Etablissement Français du Sang—Bretagne, Brest, France
| | - Mathieu Kerbiriou
- Inserm, UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies", Univ Brest, EFS, IBSAM, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
| | - Pascal Trouvé
- Inserm, UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies", Univ Brest, EFS, IBSAM, Brest, France
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12
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Affiliation(s)
- George M. Burslem
- Departments of Molecular,
Cellular, and Developmental Biology, Chemistry, and Pharmacology, Yale University, 219 Prospect Street, New Haven, Connecticut 06511, United States
| | - Craig M. Crews
- Departments of Molecular,
Cellular, and Developmental Biology, Chemistry, and Pharmacology, Yale University, 219 Prospect Street, New Haven, Connecticut 06511, United States
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13
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Vauthier V, Housset C, Falguières T. Targeted pharmacotherapies for defective ABC transporters. Biochem Pharmacol 2017; 136:1-11. [DOI: 10.1016/j.bcp.2017.02.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 02/23/2017] [Indexed: 02/07/2023]
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14
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Rafeeq MM, Murad HAS. Cystic fibrosis: current therapeutic targets and future approaches. J Transl Med 2017; 15:84. [PMID: 28449677 PMCID: PMC5408469 DOI: 10.1186/s12967-017-1193-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 04/23/2017] [Indexed: 01/01/2023] Open
Abstract
Objectives Study of currently approved drugs and exploration of future clinical development pipeline therapeutics for cystic fibrosis, and possible limitations in their use. Methods Extensive literature search using individual and a combination of key words related to cystic fibrosis therapeutics. Key findings Cystic fibrosis is an autosomal recessive disorder due to mutations in CFTR gene leading to abnormality of chloride channels in mucus and sweat producing cells. Respiratory system and GIT are primarily involved but eventually multiple organs are affected leading to life threatening complications. Management requires drug therapy, extensive physiotherapy and nutritional support. Previously, the focus was on symptomatic improvement and complication prevention but recently the protein rectifiers are being studied which are claimed to correct underlying structural and functional abnormalities. Some improvement is observed by the corrector drugs. Other promising approaches are gene therapy, targeting of cellular interactomes, and newer drugs for symptomatic improvement. Conclusions The treatment has a long way to go as most of the existing therapeutics is for older children. Other limiting factors include mutation class, genetic profile, drug interactions, adverse effects, and cost. Novel approaches like gene transfer/gene editing, disease modeling and search for alternative targets are warranted.
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Affiliation(s)
- Misbahuddin M Rafeeq
- Department of Pharmacology, Faculty of Medicine, King Abdulaziz University, Rabigh Campus, Jeddah, 21589, Saudi Arabia.
| | - Hussam Aly Sayed Murad
- Department of Pharmacology, Faculty of Medicine, King Abdulaziz University, Rabigh Campus, Jeddah, 21589, Saudi Arabia.,Department of Pharmacology, Faculty of Medicine, Ain Shams University, Cairo, 11562, Egypt
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15
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Vij N. Nano-based rescue of dysfunctional autophagy in chronic obstructive lung diseases. Expert Opin Drug Deliv 2016; 14:483-489. [PMID: 27561233 DOI: 10.1080/17425247.2016.1223040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION ΔF508-CFTR (cystic fibrosis transmembrane conductance regulator) is a common CF-mutation that is known to induce oxidative-inflammatory stress through activation of reactive oxygen species (ROS), which induces autophagy-impairment resulting in accumulation of CFTR in aggresome-bodies. Cysteamine, the reduced form of cystamine, is a FDA-approved drug that has anti-oxidant, anti-bacterial, and mucolytic properties. This drug has been shown in a recent clinical trial to decrease lung inflammation and improve lung function in CF patients by potentially restoring autophagy and allowing CFTR to be trafficked to the cell membrane. Areas covered: The delivery of cysteamine to airway epithelia of chronic subjects prerequisite the need for a delivery system to allow rescue of dysfunctional autophagy. Expert opinion: We anticipate based on our ongoing studies that PLGA-PEG- or Dendrimer-mediated cysteamine delivery could allow sustained airway delivery over standard cysteamine tablets or delay release capsules that are currently used for systemic treatment. In addition, proposed nano-based autophagy induction strategy can also allow rescue of cigarette smoke (CS) induced acquired-CFTR dysfunction seen in chronic obstructive pulmonary disease (COPD)-emphysema subjects. The CS induced acquired-CFTR dysfunction involves CFTR-accumulation in aggresome-bodies that can be rescued by an autophagy-inducing antioxidant drug, cysteamine. Moreover, chronic CS-exposure generates ROS that induces overall protein-misfolding and aggregation of ubiquitinated-proteins as aggresome-bodies via autophagy-impairment that can be also be resolved by treatment with autophagy-inducing antioxidant drug, cysteamine.
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Affiliation(s)
- Neeraj Vij
- a College of Medicine , Central Michigan University , Mount Pleasant , MI , USA.,b Department of Pediatric Respiratory Sciences , The Johns Hopkins School of Medicine , Baltimore , MD , USA
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16
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Wentzel JL, Virella-Lowell I, Schlosser RJ, Soler ZM. Quantitative sinonasal symptom assessment in an unselected pediatric population with cystic fibrosis. Am J Rhinol Allergy 2016; 29:357-61. [PMID: 26358346 DOI: 10.2500/ajra.2015.29.4196] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
INTRODUCTION The aim of this study was to establish baseline sinonasal quality of life scores in an unselected pediatric population with cystic fibrosis (CF) and to test the correlation of those scores with various clinical outcome measurements. METHODS A total of 50 consecutive children, ages 2-12 years, seen routinely in a large CF clinic were evaluated by using the Sinus and Nasal Quality of Life Survey (SN-5) tool at the time of their visit. At this time, the parent or guardian of the child was also questioned about recent episodes of sinusitis, antibiotic prescriptions for sinusitis, recent hospitalizations, and days missed from school or recreational activities due to sinonasal symptoms. CF genotype, pulmonary function, recent sinus surgeries, and computed tomography scores were established by thorough chart review. RESULTS The average SN-5 score of this group was lower than published averages in children with baseline, preoperative, or postoperative chronic sinusitis, and demonstrated significant correlations with a visual analog scale, recent episodes of sinusitis, antibiotic prescriptions for sinusitis, and the number of days missed from school or recreational activities due to sinonasal symptoms, with a nonsignificant trend observed with previous sinus surgery. No correlations were seen with CF genotype, pulmonary function, or hospitalization days. Computed tomography results were overwhelmingly abnormal, and Lund-MacKay scores did not correlate with SN-5 scores or clinical outcome measurements. CONCLUSIONS The SN-5 tool provides a quick, safe, and reliable qualitative metric for monitoring sinonasal symptoms in young children with CF.
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Affiliation(s)
- Jennifer L Wentzel
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
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17
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Farinha CM, Matos P. Repairing the basic defect in cystic fibrosis - one approach is not enough. FEBS J 2015; 283:246-64. [PMID: 26416076 DOI: 10.1111/febs.13531] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/21/2015] [Accepted: 09/23/2015] [Indexed: 12/16/2022]
Abstract
Cystic fibrosis has attracted much attention in recent years due to significant advances in the pharmacological targeting of the basic defect underlying this recessive disorder: the deficient functional expression of mutant cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels at the apical membrane of epithelial cells. However, increasing evidence points to the reduced efficacy of single treatments, thus reinforcing the need to combine several therapeutic strategies to effectively target the multiple basic defect(s). Protein-repair therapies that use potentiators (activating membrane-located CFTR) or correctors (promoting the relocation of intracellular-retained trafficking mutants of CFTR) in frequent mutations such as F508del and G551D have been put forward and made their way to the clinic with moderate to good efficiency. However, alternative (or additional) approaches targeting the membrane stability of mutant proteins, or correcting the cellular phenotype through a direct effect upon other ion channels (affecting the overall electrolyte transport or simply promoting alternative chloride transport) or targeting less frequent mutations (splicing variants, for example), have been proposed and tested in the field of cystic fibrosis (CF). Here, we cover the different strategies that rely on novel findings concerning the CFTR interactome and signalosome through which it might be possible to further influence the cellular trafficking and post-translational modification machinery (to increase rescued CFTR abundance and membrane stability). We also highlight the new data on strategies aiming at the regulation of sodium absorption or to increase chloride transport through alternative channels. The development and implementation of these complementary approaches will pave the way to combinatorial therapeutic strategies with increased benefit to CF patients.
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Affiliation(s)
- Carlos M Farinha
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal
| | - Paulo Matos
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal.,Department of Human Genetics, National Health Institute 'Dr. Ricardo Jorge', Lisboa, Portugal
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18
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Sphingosine-1-Phosphate Is a Novel Regulator of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Activity. PLoS One 2015; 10:e0130313. [PMID: 26079370 PMCID: PMC4469317 DOI: 10.1371/journal.pone.0130313] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 05/18/2015] [Indexed: 01/12/2023] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) attenuates sphingosine-1-phosphate (S1P) signaling in resistance arteries and has emerged as a prominent regulator of myogenic vasoconstriction. This investigation demonstrates that S1P inhibits CFTR activity via adenosine monophosphate-activated kinase (AMPK), establishing a potential feedback link. In Baby Hamster Kidney (BHK) cells expressing wild-type human CFTR, S1P (1μmol/L) attenuates forskolin-stimulated, CFTR-dependent iodide efflux. S1P's inhibitory effect is rapid (within 30 seconds), transient and correlates with CFTR serine residue 737 (S737) phosphorylation. Both S1P receptor antagonism (4μmol/L VPC 23019) and AMPK inhibition (80μmol/L Compound C or AMPK siRNA) attenuate S1P-stimluated (i) AMPK phosphorylation, (ii) CFTR S737 phosphorylation and (iii) CFTR activity inhibition. In BHK cells expressing the ΔF508 CFTR mutant (CFTRΔF508), the most common mutation causing cystic fibrosis, both S1P receptor antagonism and AMPK inhibition enhance CFTR activity, without instigating discernable correction. In summary, we demonstrate that S1P/AMPK signaling transiently attenuates CFTR activity. Since our previous work positions CFTR as a negative S1P signaling regulator, this signaling link may positively reinforce S1P signals. This discovery has clinical ramifications for the treatment of disease states associated with enhanced S1P signaling and/or deficient CFTR activity (e.g. cystic fibrosis, heart failure). S1P receptor/AMPK inhibition could synergistically enhance the efficacy of therapeutic strategies aiming to correct aberrant CFTR trafficking.
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19
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Farinha CM, Sousa M, Canato S, Schmidt A, Uliyakina I, Amaral MD. Increased efficacy of VX-809 in different cellular systems results from an early stabilization effect of F508del-CFTR. Pharmacol Res Perspect 2015; 3:e00152. [PMID: 26171232 PMCID: PMC4492728 DOI: 10.1002/prp2.152] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/15/2015] [Accepted: 04/22/2015] [Indexed: 12/11/2022] Open
Abstract
Cystic fibrosis (CF), the most common recessive autosomal disease among Caucasians, is caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein. The most common mutation, F508del, leads to CFTR impaired plasma membrane trafficking. Therapies modulating CFTR basic defect are emerging, such as VX-809, a corrector of F508del-CFTR traffic which just succeeded in a Phase III clinical trial. We recently showed that VX-809 is additive to two other correctors (VRT-325 and compound 4a). Here, we aimed to determine whether the differential rescuing by these compounds results from cell-specific factors or rather from distinct effects at the early biogenesis and/or processing. The rescuing efficiencies of the above three correctors were first compared in different cellular models (primary respiratory cells, cystic fibrosis bronchial epithelial and baby hamster kidney [BHK] cell lines) by functional approaches: micro-Ussing chamber and iodide efflux. Next, biochemical methods (metabolic labeling, pulse-chase and immunoprecipitation) were used to determine their impact on CFTR biogenesis / processing. Functional analyses revealed that VX-809 has the greatest rescuing efficacy and that the relative efficiencies of the three compounds are essentially maintained in all three cellular models tested. Nevertheless, biochemical data show that VX-809 significantly stabilizes F508del-CFTR immature form, an effect that is not observed for C3 nor C4. VX-809 and C3 also significantly increase accumulation of immature CFTR. Our data suggest that VX-809 increases the stability of F508del-CFTR immature form at an early phase of its biogenesis, thus explaining its increased efficacy when inducing its rescue.
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Affiliation(s)
- Carlos M Farinha
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute Campo Grande-C8, 1749-016, Lisboa, Portugal
| | - Marisa Sousa
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute Campo Grande-C8, 1749-016, Lisboa, Portugal
| | - Sara Canato
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute Campo Grande-C8, 1749-016, Lisboa, Portugal
| | - André Schmidt
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute Campo Grande-C8, 1749-016, Lisboa, Portugal
| | - Inna Uliyakina
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute Campo Grande-C8, 1749-016, Lisboa, Portugal
| | - Margarida D Amaral
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute Campo Grande-C8, 1749-016, Lisboa, Portugal
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20
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Shah K, Cheng Y, Hahn B, Bridges R, Bradbury NA, Mueller DM. Synonymous codon usage affects the expression of wild type and F508del CFTR. J Mol Biol 2015; 427:1464-1479. [PMID: 25676312 DOI: 10.1016/j.jmb.2015.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/03/2015] [Accepted: 02/04/2015] [Indexed: 10/24/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel composed of 1480 amino acids. The major mutation responsible for cystic fibrosis results in loss of amino acid residue, F508 (F508del). Loss of F508 in CFTR alters the folding pathway resulting in endoplasmic-reticulum-associated degradation. This study investigates the role of synonymous codon in the expression of CFTR and CFTR F508del in human HEK293 cells. DNA encoding the open reading frame (ORF) for CFTR containing synonymous codon replacements was expressed using a heterologous vector integrated into the genome. The results indicate that the codon usage greatly affects the expression of CFTR. While the promoter strength driving expression of the ORFs was largely unchanged and the mRNA half-lives were unchanged, the steady-state levels of the mRNA varied by as much as 30-fold. Experiments support that this apparent inconsistency is attributed to nonsense mediated decay independent of exon junction complex. The ratio of CFTR/mRNA indicates that mRNA containing native codons was more efficient in expressing mature CFTR as compared to mRNA containing synonymous high-expression codons. However, when F508del CFTR was expressed after codon optimization, a greater percentage of the protein escaped endoplasmic-reticulum-associated degradation resulting in considerable levels of mature F508del CFTR on the plasma membrane, which showed channel activity. These results indicate that codon usage has an effect on mRNA levels and protein expression, for CFTR, and likely on chaperone-assisted folding pathway, for F508del CFTR.
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Affiliation(s)
- Kalpit Shah
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University, The Chicago Medical School, North Chicago, IL 60064, USA; Department of Physiology and Biophysics, Rosalind Franklin University, The Chicago Medical School, North Chicago, IL 60064, USA
| | - Yi Cheng
- Department of Physiology and Biophysics, Rosalind Franklin University, The Chicago Medical School, North Chicago, IL 60064, USA
| | - Brian Hahn
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University, The Chicago Medical School, North Chicago, IL 60064, USA
| | - Robert Bridges
- Department of Physiology and Biophysics, Rosalind Franklin University, The Chicago Medical School, North Chicago, IL 60064, USA
| | - Neil A Bradbury
- Department of Physiology and Biophysics, Rosalind Franklin University, The Chicago Medical School, North Chicago, IL 60064, USA
| | - David M Mueller
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University, The Chicago Medical School, North Chicago, IL 60064, USA.
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21
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Loganathan SK, Casey JR. Corneal dystrophy-causing SLC4A11 mutants: suitability for folding-correction therapy. Hum Mutat 2014; 35:1082-91. [PMID: 24916015 DOI: 10.1002/humu.22601] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/28/2014] [Indexed: 12/25/2022]
Abstract
SLC4A11 mutations cause some cases of the corneal endothelial dystrophies, congenital hereditary endothelial corneal dystrophy type 2 (CHED2), Harboyan syndrome (HS), and Fuchs endothelial corneal dystrophy (FECD). SLC4A11 protein was recently identified as facilitating water flux across membranes. SLC4A11 point mutations usually cause SLC4A11 misfolding and retention in the endoplasmic reticulum (ER). We set about to test the feasibility of rescuing misfolded SLC4A11 protein to the plasma membrane as a therapeutic approach. Using a transfected HEK293 cell model, we measured functional activity present in cells expressing SLC4A11 variants in combinations representing the state found in CHED2 carriers, affected CHED2, FECD individuals, and unaffected individuals. These cells manifest respectively about 60%, 5%, and 25% of the water flux activity, relative to the unaffected (WT alone). ER-retained CHED2 mutant SLC4A11 protein could be rescued to the plasma membrane, where it conferred 25%-30% of WT water flux level. Further, some ER-retained CHED2 mutants expressed at 30°C supported increased water flux compared with 37°C cultures. Caspase activation and cell vitality assays revealed that expression of SLC4A11 mutants in HEK293 cells does not induce cell death. We conclude that therapeutics able to increase cell surface localization of ER-retained SLC4A11 mutants hold promise to treat CHED2 and FECD patients.
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Affiliation(s)
- Sampath K Loganathan
- Department of Biochemistry, Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
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22
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Favia M, Mancini MT, Bezzerri V, Guerra L, Laselva O, Abbattiscianni AC, Debellis L, Reshkin SJ, Gambari R, Cabrini G, Casavola V. Trimethylangelicin promotes the functional rescue of mutant F508del CFTR protein in cystic fibrosis airway cells. Am J Physiol Lung Cell Mol Physiol 2014; 307:L48-61. [PMID: 24816489 DOI: 10.1152/ajplung.00305.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) carrying the F508del mutation is retained in endoplasmic reticulum and fails to traffic to the cell surface where it functions as a protein kinase A (PKA)-activated chloride channel. Pharmacological correctors that rescue the trafficking of F508del CFTR may overcome this defect; however, the rescued F508del CFTR still displays reduced chloride permeability. Therefore, a combined administration of correctors and potentiators of the gating defect is ideal. We recently found that 4,6,4'-trimethylangelicin (TMA), besides inhibiting the expression of the IL-8 gene in airway cells in which the inflammatory response was challenged with Pseudomonas aeruginosa, also potentiates the cAMP/PKA-dependent activation of wild-type CFTR or F508del CFTR that has been restored to the plasma membrane. Here, we demonstrate that long preincubation with nanomolar concentrations of TMA is able to effectively rescue both F508del CFTR-dependent chloride secretion and F508del CFTR cell surface expression in both primary or secondary airway cell monolayers homozygous for F508del mutation. The correction effect of TMA seems to be selective for CFTR and persisted for 24 h after washout. Altogether, the results suggest that TMA, besides its anti-inflammatory and potentiator activities, also displays corrector properties.
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Affiliation(s)
- Maria Favia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Maria T Mancini
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Valentino Bezzerri
- Laboratory of Molecular Pathology, Department of Pathology and Diagnostics, University Hospital Verona, Verona, Italy
| | - Lorenzo Guerra
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Onofrio Laselva
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Anna C Abbattiscianni
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Lucantonio Debellis
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Stephan J Reshkin
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Roberto Gambari
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy; and
| | - Giulio Cabrini
- Laboratory of Molecular Pathology, Department of Pathology and Diagnostics, University Hospital Verona, Verona, Italy
| | - Valeria Casavola
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy; Centre of Excellence in Comparative Genomics, University of Bari, Bari, Italy
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23
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Using pharmacological chaperones to restore proteostasis. Pharmacol Res 2014; 83:3-9. [PMID: 24747662 DOI: 10.1016/j.phrs.2014.04.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 04/02/2014] [Accepted: 04/02/2014] [Indexed: 12/18/2022]
Abstract
Normal organismal physiology depends on the maintenance of proteostasis in each cellular compartment to achieve a delicate balance between protein synthesis, folding, trafficking, and degradation while minimizing misfolding and aggregation. Defective proteostasis leads to numerous protein misfolding diseases. Pharmacological chaperones are cell-permeant small molecules that promote the proper folding and trafficking of a protein via direct binding to that protein. They stabilize their target protein in a protein-pharmacological chaperone state, increasing the natively folded protein population that can effectively engage trafficking machinery for transport to the final destination for function. Here, as regards the application of pharmacological chaperones, we focus on their capability to promote the folding and trafficking of lysosomal enzymes, G protein coupled receptors (GPCRs), and ion channels, each of which is presently an important drug target. Pharmacological chaperones hold great promise as potential therapeutics to ameliorate a variety of protein misfolding diseases.
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Benz N, Le Hir S, Norez C, Kerbiriou M, Calvez ML, Becq F, Trouvé P, Férec C. Improvement of chloride transport defect by gonadotropin-releasing hormone (GnRH) in cystic fibrosis epithelial cells. PLoS One 2014; 9:e88964. [PMID: 24586461 PMCID: PMC3929654 DOI: 10.1371/journal.pone.0088964] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 01/16/2014] [Indexed: 11/18/2022] Open
Abstract
Cystic fibrosis (CF), the most common autosomal recessive disease in Caucasians, is due to mutations in the CFTR gene. F508del, the most frequent mutation in patients, impairs CFTR protein folding and biosynthesis. The F508del-CFTR protein is retained in the endoplasmic reticulum (ER) and its traffic to the plasma membrane is altered. Nevertheless, if it reaches the cell surface, it exhibits a Cl− channel function despite a short half-life. Pharmacological treatments may target the F508del-CFTR defect directly by binding to the mutant protein or indirectly by altering cellular proteostasis, and promote its plasma membrane targeting and stability. We previously showed that annexine A5 (AnxA5) directly binds to F508del-CFTR and, when overexpressed, promotes its membrane stability, leading to the restoration of some Cl− channel function in cells. Because Gonadotropin-Releasing Hormone (GnRH) increases AnxA5 expression in some cells, we tested it in CF cells. We showed that human epithelial cells express GnRH-receptors (GnRH-R) and that GnRH induces an AnxA5 overexpression and an increased Cl− channel function in F508del-CFTR cells, due to an increased stability of the protein in the membranes. Beside the numerous physiological implications of the GnRH-R expression in epithelial cells, we propose that a topical use of GnRH is a potential treatment in CF.
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Affiliation(s)
- Nathalie Benz
- Institut National de la Santé et de la Recherche Médicale, UMR1078, Brest, France
- Association Gaetan Saleun, Brest, France
| | - Sophie Le Hir
- Institut National de la Santé et de la Recherche Médicale, UMR1078, Brest, France
- C.H.U. Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Caroline Norez
- Institut de Physiologie et Biologie Cellulaires, Centre national de la recherche scientifique FRE 3511, Université de Poitiers, Poitiers, France
| | - Mathieu Kerbiriou
- Institut National de la Santé et de la Recherche Médicale, UMR1078, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
| | - Marie-Laure Calvez
- Institut National de la Santé et de la Recherche Médicale, UMR1078, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
| | - Frédéric Becq
- Institut de Physiologie et Biologie Cellulaires, Centre national de la recherche scientifique FRE 3511, Université de Poitiers, Poitiers, France
| | - Pascal Trouvé
- Institut National de la Santé et de la Recherche Médicale, UMR1078, Brest, France
- * E-mail: (PT); (CF)
| | - Claude Férec
- Institut National de la Santé et de la Recherche Médicale, UMR1078, Brest, France
- C.H.U. Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
- Université de Bretagne Occidentale, Faculté de Médecine et des sciences de la santé, Brest, France
- Etablissement Français du Sang - Bretagne, Brest, France
- * E-mail: (PT); (CF)
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Pharmacological chaperoning: a primer on mechanism and pharmacology. Pharmacol Res 2014; 83:10-9. [PMID: 24530489 DOI: 10.1016/j.phrs.2014.01.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 12/26/2022]
Abstract
Approximately forty percent of diseases are attributable to protein misfolding, including those for which genetic mutation produces misfolding mutants. Intriguingly, many of these mutants are not terminally misfolded since native-like folding, and subsequent trafficking to functional locations, can be induced by target-specific, small molecules variably termed pharmacological chaperones, pharmacoperones, or pharmacochaperones (PCs). PC targets include enzymes, receptors, transporters, and ion channels, revealing the breadth of proteins that can be engaged by ligand-assisted folding. The purpose of this review is to provide an integrated primer of the diverse mechanisms and pharmacology of PCs. In this regard, we examine the structural mechanisms that underlie PC rescue of misfolding mutants, including the ability of PCs to act as surrogates for defective intramolecular interactions and, at the intermolecular level, overcome oligomerization deficiencies and dominant negative effects, as well as influence the subunit stoichiometry of heteropentameric receptors. Not surprisingly, PC-mediated structural correction of misfolding mutants normalizes interactions with molecular chaperones that participate in protein quality control and forward-trafficking. A variety of small molecules have proven to be efficacious PCs and the advantages and disadvantages of employing orthostatic antagonists, active-site inhibitors, orthostatic agonists, and allosteric modulator PCs are considered. Also examined is the possibility that several therapeutic agents may have unrecognized activity as PCs, and this chaperoning activity may mediate/contribute to therapeutic action and/or account for adverse effects. Lastly, we explore evidence that pharmacological chaperoning exploits intrinsic ligand-assisted folding mechanisms. Given the widespread applicability of PC rescue of mutants associated with protein folding disorders, both in vitro and in vivo, the therapeutic potential of PCs is vast. This is most evident in the treatment of lysosomal storage disorders, cystic fibrosis, and nephrogenic diabetes insipidus, for which proof of principle in humans has been demonstrated.
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The cystic fibrosis V232D mutation inhibits CFTR maturation by disrupting a hydrophobic pocket rather than formation of aberrant interhelical hydrogen bonds. Biochem Pharmacol 2014; 88:46-57. [PMID: 24412276 DOI: 10.1016/j.bcp.2013.12.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 12/30/2013] [Accepted: 12/31/2013] [Indexed: 11/21/2022]
Abstract
Processing mutations that inhibit folding and trafficking of CFTR are the main cause of cystic fibrosis. Repair of CFTR mutants requires an understanding of the mechanisms of misfolding caused by processing mutations. Previous studies on helix-loop-helix fragments of the V232D processing mutation suggested that its mechanism was to lock transmembrane (TM) segments 3 and 4 together by a non-native hydrogen bond (Asp232(TM4)/Gln207(TM3)). Here, we performed mutational analysis to test for Asp232/Gln207 interactions in full-length CFTR. The rationale was that a V232N mutation should mimic V232D and a V232D/Q207A mutant should mature if the processing defect was caused by hydrogen bonds. We report that only Val232 mutations to charged amino acids severely blocked CFTR maturation. The V232N mutation did not mimic V232D as V232N showed 40% maturation compared to 2% for V232D. Mutation of Val232 to large nonpolar residues (Leu, Phe) had little effect. The Q207L mutation did not rescue V232D because Q207L showed about 50% maturation in the presence of corrector VX-809 while V232D/Q207A could no longer be rescued. These results suggest that V232D inhibits maturation by disrupting a hydrophobic pocket between TM segments rather than forming a non-native hydrogen bond. Disulfide cross-linking analysis of cysteines W356C(TM6) and W1145C(TM12) suggest that the V232D mutation inhibits maturation by trapping CFTR as a partially folded intermediate. Since correctors can efficiently rescue V232D CFTR, the results suggest that hydrophilic processing mutations facing a hydrophobic pocket are good candidates for rescue with pharmacological chaperones.
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Hanrahan JW, Sampson HM, Thomas DY. Novel pharmacological strategies to treat cystic fibrosis. Trends Pharmacol Sci 2013; 34:119-25. [PMID: 23380248 DOI: 10.1016/j.tips.2012.11.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 11/28/2012] [Accepted: 11/28/2012] [Indexed: 12/15/2022]
Abstract
Cystic fibrosis (CF) is a lethal disease caused by mutations in the CFTR gene. The most frequent mutation is deletion of a phenylalanine residue (ΔF508) that results in retention of the mutant, but otherwise functional, protein in the endoplasmic reticulum (ER). There have been recent advances in the identification of chemically diverse corrector compounds that allow ΔF508-CFTR protein to traffic from the ER to the plasma membrane. The most studied correctors fall into two categories, pharmacological chaperones that bind to the mutant protein and circumvent its recognition by the cellular protein quality control systems and proteostasis regulators that modify the cellular pathways responsible for protein quality control and trafficking. This review focuses on recent advances in the field, strategies for the development of drugs from corrector compounds for the treatment of CF, and identification of their targets and mechanism(s) of action.
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Affiliation(s)
- John W Hanrahan
- Cystic Fibrosis Translation Research centre, Faculty of Medicine, McGill University, 3655 Promenade Sir William Osler, Montreal H3G 1Y6, Quebec, Canada
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Merk D, Schubert-Zsilavecz M. Repairing mutated proteins – development of small molecules targeting defects in the cystic fibrosis transmembrane conductance regulator. Expert Opin Drug Discov 2013; 8:691-708. [DOI: 10.1517/17460441.2013.788495] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Wilke M, Bot A, Jorna H, Scholte BJ, de Jonge HR. Rescue of murine F508del CFTR activity in native intestine by low temperature and proteasome inhibitors. PLoS One 2012; 7:e52070. [PMID: 23284872 PMCID: PMC3528711 DOI: 10.1371/journal.pone.0052070] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 11/15/2012] [Indexed: 11/19/2022] Open
Abstract
Most patients with Cystic Fibrosis (CF) carry at least one allele with the F508del mutation, resulting in a CFTR chloride channel protein with a processing, gating and stability defect, but with substantial residual activity when correctly sorted to the apical membranes of epithelial cells. New therapies are therefore aimed at improving the folding and trafficking of F508del CFTR, (CFTR correctors) or at enhancing the open probability of the CFTR chloride channel (CFTR potentiators). Preventing premature breakdown of F508del CFTR is an alternative or additional strategy, which is investigated in this study. We established an ex vivo assay for murine F508del CFTR rescue in native intestinal epithelium that can be used as a pre-clinical test for candidate therapeutics. Overnight incubation of muscle stripped ileum in modified William's E medium at low temperature (26°C), and 4 h or 6 h incubation at 37°C with different proteasome inhibitors (PI: ALLN, MG-132, epoxomicin, PS341/bortezomib) resulted in fifty to hundred percent respectively of the wild type CFTR mediated chloride secretion (forskolin induced short-circuit current). The functional rescue was accompanied by enhanced expression of the murine F508del CFTR protein at the apical surface of intestinal crypts and a gain in the amount of complex-glycosylated CFTR (band C) up to 20% of WT levels. Sustained rescue in the presence of brefeldin A shows the involvement of a post-Golgi compartment in murine F508del CFTR degradation, as was shown earlier for its human counterpart. Our data show that proteasome inhibitors are promising candidate compounds for improving rescue of human F508del CFTR function, in combination with available correctors and potentiators.
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Affiliation(s)
- Martina Wilke
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.
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Molinski S, Eckford PDW, Pasyk S, Ahmadi S, Chin S, Bear CE. Functional Rescue of F508del-CFTR Using Small Molecule Correctors. Front Pharmacol 2012; 3:160. [PMID: 23055971 PMCID: PMC3458236 DOI: 10.3389/fphar.2012.00160] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 08/17/2012] [Indexed: 01/21/2023] Open
Abstract
High-throughput screens for small molecules that are effective in “correcting” the functional expression of F508del-CFTR have yielded several promising hits. Two such compounds are currently in clinical trial. Despite this success, it is clear that further advances will be required in order to restore 50% or greater of wild-type CFTR function to the airways of patients harboring the F508del-CFTR protein. Progress will be enhanced by our better understanding of the molecular and cellular defects caused by the F508del mutation, present in 90% of CF patients. The goal of this chapter is to review the current understanding of defects caused by F508del in the CFTR protein and in CFTR-mediated interactions important for its biosynthesis, trafficking, channel function, and stability at the cell surface. Finally, we will discuss the gaps in our knowledge regarding the mechanism of action of existing correctors, the unmet need to discover compounds which restore proper CFTR structure and function in CF affected tissues and new strategies for therapy development.
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Affiliation(s)
- Steven Molinski
- Programme in Molecular Structure and Function, Research Institute, Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, University of Toronto Toronto, ON, Canada
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Li H, Yang W, Mendes F, Amaral MD, Sheppard DN. Impact of the cystic fibrosis mutation F508del-CFTR on renal cyst formation and growth. Am J Physiol Renal Physiol 2012; 303:F1176-86. [PMID: 22874761 DOI: 10.1152/ajprenal.00130.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In autosomal dominant polycystic kidney disease (ADPKD), cystic fibrosis transmembrane conductance regulator (CFTR), the protein product of the gene defective in cystic fibrosis (CF), plays a crucial role in fluid accumulation, which promotes cyst swelling. Several studies have identified individuals afflicted by both ADPKD and CF. Two studies suggested that CF mutations might attenuate the severity of ADPKD, whereas a third found no evidence of a protective effect. In this study, we investigated the impact of the commonest CF mutation F508del-CFTR on the formation and growth of renal cysts. As a model system, we used Madin-Darby canine kidney (MDCK) epithelial cells engineered to express wild-type and F508del human CFTR. We grew MDCK cysts in collagen gels in the presence of the cAMP agonist forskolin and measured transepithelial resistance and Cl(-) secretion with the Ussing chamber technique and assayed cell proliferation using nonpolarized MDCK cells. When compared with untransfected MDCK cells, cells expressing wild-type CFTR generated substantial numbers of large cysts, which grew markedly over time. By contrast, MDCK cells expressing F508del-CFTR formed very few tiny cysts that failed to enlarge. Interestingly, treatment of F508del-CFTR cysts with the CFTR corrector VRT-325 and the CFTR corrector-potentiator VRT-532 increased the number, but not size, of F508del-CFTR cysts, possibly because VRT-325 inhibited strongly cell proliferation. Based on its effects on transepithelial resistance, Cl(-) secretion, and cell proliferation, we conclude that the F508del-CFTR mutation disrupts cyst formation and growth by perturbing strongly fluid accumulation within the cyst lumen without compromising epithelial integrity.
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Affiliation(s)
- Hongyu Li
- School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol, UK
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Cattaneo M, Dominici R, Cardano M, Diaferia G, Rovida E, Biunno I. Molecular chaperones as therapeutic targets to counteract proteostasis defects. J Cell Physiol 2012; 227:1226-34. [PMID: 21618531 DOI: 10.1002/jcp.22856] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The health of cells is preserved by the levels and correct folding states of the proteome, which is generated and maintained by the proteostasis network, an integrated biological system consisting of several cytoprotective and degradative pathways. Indeed, the health conditions of the proteostasis network is a fundamental prerequisite to life as the inability to cope with the mismanagement of protein folding arising from genetic, epigenetic, and micro-environment stress appears to trigger a whole spectrum of unrelated diseases. Here we describe the potential functional role of the proteostasis network in tumor biology and in conformational diseases debating on how the signaling branches of this biological system may be manipulated to develop more efficacious and selective therapeutic strategies. We discuss the dual strategy of these processes in modulating the folding activity of molecular chaperones in order to counteract the antithetic proteostasis deficiencies occurring in cancer and loss/gain of function diseases. Finally, we provide perspectives on how to improve the outcome of these disorders by taking advantage of proteostasis modeling.
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Corrector-mediated rescue of misprocessed CFTR mutants can be reduced by the P-glycoprotein drug pump. Biochem Pharmacol 2012; 83:345-54. [DOI: 10.1016/j.bcp.2011.11.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Revised: 11/17/2011] [Accepted: 11/18/2011] [Indexed: 11/18/2022]
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Alkhouri B, Denning RA, Kim Chiaw P, Eckford PDW, Yu W, Li C, Bogojeski JJ, Bear CE, Viirre RD. Synthesis and properties of molecular probes for the rescue site on mutant cystic fibrosis transmembrane conductance regulator. J Med Chem 2011; 54:8693-701. [PMID: 22074181 PMCID: PMC3241338 DOI: 10.1021/jm201335c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cystic fibrosis is a genetic disease caused by mutations in the gene for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. In vitro experiments have demonstrated that 4-methyl-2-(5-phenyl-1H-pyrazol-3-yl)phenol (VRT-532, 1) is able to partially restore the function of mutant CFTR proteins. To help elucidate the nature of the interactions between 1 and mutant CFTR, molecular probes based on the structure of 1 have been prepared. These include a photoreactive aryl azide derivative 11 and a fluorescent dansyl sulfonamide 15. Additionally, a method for hydrogen isotope exchange on 1 has been developed, which could be used for the incorporation of radioactive tritium. Using iodide efflux assays, the probe molecules have been demonstrated to modulate the activity of mutant CFTR in the same manner as 1. These probe molecules enable a number of biochemical experiments aimed at understanding how 1 rescues the function of mutant CFTR. This understanding can in turn aid in the design and development of more efficacious compounds which may serve as therapeutic agents in the treatment of cystic fibrosis.
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Affiliation(s)
- Bashar Alkhouri
- Department of Chemistry and Biology, Ryerson University, and Programme in Molecular Structure and Function, Research Institute, Hospital for Sick Children, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
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Wang W, Okeyo GO, Tao B, Hong JS, Kirk KL. Thermally unstable gating of the most common cystic fibrosis mutant channel (ΔF508): "rescue" by suppressor mutations in nucleotide binding domain 1 and by constitutive mutations in the cytosolic loops. J Biol Chem 2011; 286:41937-41948. [PMID: 21965669 DOI: 10.1074/jbc.m111.296061] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most cystic fibrosis (CF) cases are caused by the ΔF508 mutation in the CF transmembrane conductance regulator (CFTR), which disrupts both the processing and gating of this chloride channel. The cell surface expression of ΔF508-CFTR can be "rescued" by culturing cells at 26-28 °C and treating cells with small molecule correctors or intragenic suppressor mutations. Here, we determined whether these various rescue protocols induce a ΔF508-CFTR conformation that is thermally stable in excised membrane patches. We also tested the impact of constitutive cytosolic loop mutations that increase ATP-independent channel activity (K978C and K190C/K978C) on ΔF508-CFTR function. Low temperature-rescued ΔF508-CFTR channels irreversibly inactivated with a time constant of 5-6 min when excised patches were warmed from 22 °C to 36.5 °C. A panel of CFTR correctors and potentiators that increased ΔF508-CFTR maturation or channel activity failed to prevent this inactivation. Conversely, three suppressor mutations in the first nucleotide binding domain rescued ΔF508-CFTR maturation and stabilized channel activity at 36.5 °C. The constitutive loop mutations increased ATP-independent activity of low temperature-rescued ΔF508-CFTR but did not enhance protein maturation. Importantly, the ATP-independent activities of these ΔF508-CFTR constructs were stable at 36.5 °C, whereas their ATP-dependent activities were not. Single channel recordings of this thermally stable ATP-independent activity revealed dynamic gating and unitary currents of normal amplitudes. We conclude that: (i) ΔF508-CFTR gating is highly unstable at physiologic temperature; (ii) most rescue protocols do not prevent this thermal instability; and (iii) ATP-independent gating and the pore are spared from ΔF508-induced thermal instability, a finding that may inform alternative treatment strategies.
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Affiliation(s)
- Wei Wang
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35294; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294.
| | - George O Okeyo
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35294; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Binli Tao
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35294; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jeong S Hong
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Kevin L Kirk
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35294; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
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Abstract
With knowledge of the molecular behaviour of the cystic fibrosis transmembrane conductance regulator (CFTR), its physiological role and dysfunction in cystic fibrosis (CF), therapeutic strategies are now being developed that target the root cause of CF rather than disease symptoms. Here, we review progress towards the development of rational new therapies for CF. We highlight the discovery of small molecules that rescue the cell surface expression and defective channel gating of CF mutants, termed CFTR correctors and CFTR potentiators, respectively. We draw attention to alternative approaches to restore epithelial ion transport to CF epithelia, including inhibitors of the epithelial Na(+) channel (ENaC) and activators of the Ca(2+)-activated Cl(-) channel TMEM16A. The expertise required to translate small molecules identified in the laboratory to drugs for CF patients depends on our ability to coordinate drug development at an international level and our ability to provide pertinent biological information using suitable disease models.
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Phuan PW, Yang B, Knapp JM, Wood AB, Lukacs GL, Kurth MJ, Verkman AS. Cyanoquinolines with independent corrector and potentiator activities restore ΔPhe508-cystic fibrosis transmembrane conductance regulator chloride channel function in cystic fibrosis. Mol Pharmacol 2011; 80:683-93. [PMID: 21730204 DOI: 10.1124/mol.111.073056] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ΔPhe508 mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) protein impairs its folding, stability, and chloride channel gating. Although small molecules that separately correct defective ΔPhe508-CFTR folding/cellular processing ("correctors") or chloride channel gating ("potentiators") have been discovered and are in clinical trials, single compounds with bona fide dual corrector and potentiator activities have not been identified. Here, screening of ∼110,000 small molecules not tested previously revealed a cyanoquinoline class of compounds with independent corrector and potentiator activities (termed CoPo). Analysis of 180 CoPo analogs revealed 6 compounds with dual corrector and potentiator activities and 13 compounds with only potentiator activity. N-(2-((3-Cyano-5,7-dimethylquinolin-2-yl)amino)ethyl)-3-methoxybenzamide (CoPo-22), which was synthesized in six steps in 52% overall yield, had low micromolar EC(50) for ΔPhe508-CFTR corrector and potentiator activities by short-circuit current assay. Maximal corrector and potentiator activities were comparable with those conferred by the bithiazole Corr-4a and the flavone genistein, respectively. CoPo-22 also activated wild-type and G551D CFTR chloride conductance within minutes in a forskolin-dependent manner. Compounds with dual corrector and potentiator activities may be useful for single-drug treatment of cystic fibrosis caused by ΔPhe508 mutation.
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Affiliation(s)
- Puay-Wah Phuan
- Department of Medicine, University of California, San Francisco, California, USA
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Pyle LC, Ehrhardt A, Mitchell LH, Fan L, Ren A, Naren AP, Li Y, Clancy JP, Bolger GB, Sorscher EJ, Rowe SM. Regulatory domain phosphorylation to distinguish the mechanistic basis underlying acute CFTR modulators. Am J Physiol Lung Cell Mol Physiol 2011; 301:L587-97. [PMID: 21724857 DOI: 10.1152/ajplung.00465.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Modulator compounds intended to overcome disease-causing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) show significant promise in clinical testing for cystic fibrosis. However, the mechanism(s) of action underlying these compounds are not fully understood. Activation of CFTR ion transport requires PKA-regulated phosphorylation of the regulatory domain (R-D) and dimerization of the nucleotide binding domains. Using a newly developed assay, we evaluated nine compounds including both CFTR potentatiators and activators discovered via various high-throughput screening strategies to acutely augment CFTR activity. We found considerable differences in the effects on R-D phosphorylation. Some (including UC(CF)-152) stimulated robust phosphorylation, and others had little effect (e.g., VRT-532 and VX-770). We then compared CFTR activation by UC(CF)-152 and VRT-532 in Ussing chamber studies using two epithelial models, CFBE41o(-) and Fischer rat thyroid cells, expressing various CFTR forms. UC(CF)-152 activated wild-type-, G551D-, and rescued F508del-CFTR currents but did not potentiate cAMP-mediated CFTR activation. In contrast, VRT-532 moderately activated CFTR short-circuit current and strongly potentiated forskolin-mediated current. Combined with the result that UC(CF)-152, but not VRT-532 or VX-770, acts by increasing CFTR R-D phosphorylation, these findings indicate that potentiation of endogenous cAMP-mediated activation of mutant CFTR is not due to a pathway involving augmented R-D phosphorylation. This study presents an assay useful to distinguish preclinical compounds by a crucial mechanism underlying CFTR activation, delineates two types of compound able to acutely augment CFTR activity (e.g., activators and potentiators), and demonstrates that a number of different mechanisms can be successfully employed to activate mutant CFTR.
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Affiliation(s)
- Louise C Pyle
- Departments of Genetics, University of Alabama at Birmingham, 35294-0006, USA
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Caldwell RA, Grove DE, Houck SA, Cyr DM. Increased folding and channel activity of a rare cystic fibrosis mutant with CFTR modulators. Am J Physiol Lung Cell Mol Physiol 2011; 301:L346-52. [PMID: 21642448 DOI: 10.1152/ajplung.00044.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cystic fibrosis (CF) is a lethal recessive genetic disease caused by mutations in the CFTR gene. The gene product is a PKA-regulated anion channel that is important for fluid and electrolyte transport in the epithelia of lung, gut, and ducts of the pancreas and sweat glands. The most common CFTR mutation, ΔF508, causes a severe, but correctable, folding defect and gating abnormality, resulting in negligible CFTR function and disease. There are also a large number of rare CF-related mutations where disease is caused by CFTR misfolding. Yet the extent to which defective biogenesis of these CFTR mutants can be corrected is not clear. CFTRV232D is one such mutant that exhibits defective folding and trafficking. CFTRΔF508 misfolding is difficult to correct, but defective biogenesis of CFTRV232D is corrected to near wild-type levels by small-molecule folding correctors in development as CF therapeutics. To determine if CFTRV232D protein is competent as a Cl(-) channel, we utilized single-channel recordings from transfected human embryonic kidney (HEK-293) cells. After PKA stimulation, CFTRV232D channels were detected in patches with a unitary Cl(-) conductance indistinguishable from that of CFTR. Yet the frequency of detecting CFTRV232D channels was reduced to ∼20% of patches compared with 60% for CFTR. The folding corrector Corr-4a increased the CFTRV232D channel detection rate and activity to levels similar to CFTR. CFTRV232D-corrected channels were inhibited with CFTR(inh-172) and stimulated fourfold by the CFTR channel potentiator VRT-532. These data suggest that CF patients with rare mutations that cause CFTR misfolding, such as CFTRV232D, may benefit from treatment with folding correctors and channel potentiators in development to restore CFTRΔF508 function.
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Affiliation(s)
- Ray A Caldwell
- Dept. of Cell and Developmental Biology, Univ. of North Carolina, Chapel Hill, NC 27599, USA.
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Pedemonte N, Tomati V, Sondo E, Caci E, Millo E, Armirotti A, Damonte G, Zegarra-Moran O, Galietta LJV. Dual activity of aminoarylthiazoles on the trafficking and gating defects of the cystic fibrosis transmembrane conductance regulator chloride channel caused by cystic fibrosis mutations. J Biol Chem 2011; 286:15215-26. [PMID: 21383017 PMCID: PMC3083174 DOI: 10.1074/jbc.m110.184267] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A large fraction of mutations causing cystic fibrosis impair the function of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel by causing reduced channel activity (gating defect) and/or impaired exit from the endoplasmic reticulum (trafficking defect). Such defects need to be treated with separate pharmacological compounds termed potentiators and correctors, respectively. Here, we report the characterization of aminoarylthiazoles (AATs) as compounds having dual activity. Cells expressing mutant CFTR were studied with functional assays (fluorescence-based halide transport and short circuit current measurements) to assess the effect of acute and chronic treatment with compounds. We found that AATs are effective on F508del, the most frequent cystic fibrosis mutation, which is associated with both a gating and a trafficking defect. AATs are also effective on mutations like G1349D and G551D, which cause only a gating defect. Evaluation of a panel of AAT analogs identified EN277I as the most effective compound. Incubation of cells expressing mutant CFTR with EN277I caused a strong stimulation of channel activity as demonstrated by single channel recordings. Compounds with dual activity such as AATs may be useful for the development of effective drugs for the treatment of cystic fibrosis.
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Affiliation(s)
- Nicoletta Pedemonte
- Laboratorio di Genetica Molecolare, Istituto Giannina Gaslini, Genova, Italy
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Vilas GL, Morgan PE, Loganathan SK, Quon A, Casey JR. A Biochemical Framework for SLC4A11, the Plasma Membrane Protein Defective in Corneal Dystrophies. Biochemistry 2011; 50:2157-69. [DOI: 10.1021/bi101887z] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Gonzalo L. Vilas
- Membrane Protein Disease Research Group, Department of Physiology, and Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Canada T6G 2H7
| | - Patricio E. Morgan
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina CP1900
| | - Sampath K. Loganathan
- Membrane Protein Disease Research Group, Department of Physiology, and Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Canada T6G 2H7
| | - Anita Quon
- Membrane Protein Disease Research Group, Department of Physiology, and Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Canada T6G 2H7
| | - Joseph R. Casey
- Membrane Protein Disease Research Group, Department of Physiology, and Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Canada T6G 2H7
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Sampson H, Robert R, Liao J, Matthes E, Carlile G, Hanrahan J, Thomas D. Identification of a NBD1-Binding Pharmacological Chaperone that Corrects the Trafficking Defect of F508del-CFTR. ACTA ACUST UNITED AC 2011; 18:231-42. [DOI: 10.1016/j.chembiol.2010.11.016] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 11/09/2010] [Accepted: 11/29/2010] [Indexed: 11/28/2022]
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Kalid O, Mense M, Fischman S, Shitrit A, Bihler H, Ben-Zeev E, Schutz N, Pedemonte N, Thomas PJ, Bridges RJ, Wetmore DR, Marantz Y, Senderowitz H. Small molecule correctors of F508del-CFTR discovered by structure-based virtual screening. J Comput Aided Mol Des 2010; 24:971-91. [PMID: 20976528 DOI: 10.1007/s10822-010-9390-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 10/06/2010] [Indexed: 10/18/2022]
Abstract
Folding correctors of F508del-CFTR were discovered by in silico structure-based screening utilizing homology models of CFTR. The intracellular segment of CFTR was modeled and three cavities were identified at inter-domain interfaces: (1) Interface between the two Nucleotide Binding Domains (NBDs); (2) Interface between NBD1 and Intracellular Loop (ICL) 4, in the region of the F508 deletion; (3) multi-domain interface between NBD1:2:ICL1:2:4. We hypothesized that compounds binding at these interfaces may improve the stability of the protein, potentially affecting the folding yield or surface stability. In silico structure-based screening was performed at the putative binding-sites and a total of 496 candidate compounds from all three sites were tested in functional assays. A total of 15 compounds, representing diverse chemotypes, were identified as F508del folding correctors. This corresponds to a 3% hit rate, ~tenfold higher than hit rates obtained in corresponding high-throughput screening campaigns. The same binding sites also yielded potentiators and, most notably, compounds with a dual corrector-potentiator activity (dual-acting). Compounds harboring both activity types may prove to be better leads for the development of CF therapeutics than either pure correctors or pure potentiators. To the best of our knowledge this is the first report of structure-based discovery of CFTR modulators.
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Affiliation(s)
- Ori Kalid
- EPIX Pharmaceuticals Ltd., 3 Hayetzira Street, Ramat Gan, Israel.
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Louie RJ, Pagant S, Youn JY, Halliday JJ, Huyer G, Michaelis S, Miller EA. Functional rescue of a misfolded eukaryotic ATP-binding cassette transporter by domain replacement. J Biol Chem 2010; 285:36225-34. [PMID: 20843810 DOI: 10.1074/jbc.m110.160523] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP-binding cassette (ABC) transporters are integral membrane proteins that couple ATP binding/hydrolysis with the transport of hydrophilic substrates across lipid barriers. Deletion of Phe-670 in the first nucleotide-binding domain (NBD1) of the yeast ABC transporter, Yor1p, perturbs interdomain associations, reduces functionality, and hinders proper transport to the plasma membrane. Functionality of Yor1p-ΔF was restored upon co-expression of a peptide containing wild-type NBD1. To gain insight into the biogenesis of this important class of proteins, we defined the requirements for this rescue. We show that a misfolding lesion in NBD1 of the full-length protein is a prerequisite for functional rescue by exogenous NBD1, which is mediated by physical replacement of the dysfunctional domain by the soluble NBD1. This association does not restore trafficking of Yor1p-ΔF but instead confers catalytic activity to the small population of Yor1p-ΔF that escapes to the plasma membrane. An important coupling between the exogenous NBD1 and ICL4 within full-length aberrant Yor1p-ΔF is required for functional rescue but not for the physical interaction between the two polypeptides. Together, our genetic and biochemical data reveal that it is possible to modulate activity of ABC transporters by physically replacing dysfunctional domains.
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Affiliation(s)
- Raymond J Louie
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Nakagawa H, Wakabayashi-Nakao K, Tamura A, Toyoda Y, Koshiba S, Ishikawa T. Disruption of N-linked glycosylation enhances ubiquitin-mediated proteasomal degradation of the human ATP-binding cassette transporter ABCG2. FEBS J 2010; 276:7237-52. [PMID: 19909340 DOI: 10.1111/j.1742-4658.2009.07423.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The human ATP-binding cassette (ABC) transporter, ABCG2 (BCRP/MXR/ABCP), is a plasma membrane protein containing intramolecular and intermolecular disulfide bonds and an N-linked glycan at Asn596. We have recently reported that the intramolecular disulfide bond is a critical checkpoint for determining the degradation fates of ABCG2. In the present study, we aimed to analyze quantitatively the impact of the N-linked glycan on the protein stability of ABCG2. For this purpose, we incorporated one single copy of ABCG2 cDNA into a designated site of genomic DNA in Flp-In-293 cells to stably express ABCG2 or its variant proteins. When ABCG2 wild type-expressing cells were incubated with various N-linked glycosylation inhibitors, tunicamycin profoundly suppressed the protein expression level of ABCG2 and, accordingly, reduced the ABCG2-mediated cellular resistance to the cancer chemotherapeutic SN-38. When Asn596 was converted to Gln596, the resulting variant protein was not glycosylated, and its protein level was about one-third of the wild type level in Flp-In-293 cells. Treatment with MG132, a proteasome inhibitor, increased the level of the variant protein. Immunoblotting with anti-ubiquitin IgG1k after immunoprecipitation of ABCG2 revealed that the N596Q protein was ubiquitinated at levels that were significantly enhanced by treatment with MG132. Immunofluorescence microscopy demonstrated that treatment with MG132 increased the level of ABCG2 N596Q protein both in intracellular compartments and in the plasma membrane. In conclusion, we propose that the N-linked glycan at Asn596 is important for stabilizing de novo-synthesized ABCG2 and that disruption of this linkage results in protein destabilization and enhanced ubiquitin-mediated proteasomal degradation.
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Affiliation(s)
- Hiroshi Nakagawa
- Department of Biomolecular Engineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
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Roy G, Chalfin EM, Saxena A, Wang X. Interplay between ER exit code and domain conformation in CFTR misprocessing and rescue. Mol Biol Cell 2009; 21:597-609. [PMID: 20032308 PMCID: PMC2820424 DOI: 10.1091/mbc.e09-05-0427] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Multiple mutations in cystic fibrosis transmembrane conductance regulator (CFTR) impair its exit from the endoplasmic reticulum (ER). We compared two processing mutants: DeltaF508 and the ER exit code mutant DAA. Although both have severe kinetic processing defect, DAA but not DeltaF508 has substantial accumulation in its mature form, leading to higher level of processing at the steady state. DAA has much less profound conformational abnormalities. It has lower Hsp70 association and higher post-ER stability than DeltaF508. The ER exit code is necessary for DeltaF508 residual export and rescue. R555K, a mutation that rescues DeltaF508 misprocessing, improves Sec24 association and enhances its post-ER stability. Using in situ limited proteolysis, we demonstrated a clear change in trypsin sensitivity in DeltaF508 NBD1, which is reversed, together with that of other domains, by low temperature, R555K or both. We observed a conversion of the proteolytic pattern of DAA from the one resembling DeltaF508 to the one similar to wild-type CFTR during its maturation. Low temperature and R555K are additive in improving DeltaF508 conformational maturation and processing. Our data reveal a dual contribution of ER exit code and domain conformation to CFTR misprocessing and underscore the importance of conformational repair in effective rescue of DeltaF508.
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Affiliation(s)
- Gargi Roy
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, OH 43614, USA
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Penmatsa H, Frederick CA, Nekkalapu S, Conoley VG, Zhang W, Li C, Kappes J, Stokes DC, Naren AP. Clinical and molecular characterization of S1118F-CFTR. Pediatr Pulmonol 2009; 44:1003-9. [PMID: 19774621 PMCID: PMC2821577 DOI: 10.1002/ppul.21092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Cystic fibrosis is a lethal autosomal recessive disorder usually associated with lung disease, pancreatic insufficiency and high sweat chloride levels. CLINICAL CASE A patient admitted to Le Bonheur Children's Medical Center (LBCMC, Memphis, TN) showed symptoms of meconium ileus which required exploratory laparotomy, bowel resection and ileostomy. Genotyping showed DeltaF508/I1027T on one chromosome and S1118F on the other. Sweat testing on three different occasions gave negative and intermediate results (22.7, 24.6 mmol/L; 55.1, 58.6 mmol/L and 55.1, 58 mmol/L) and pancreatic elastase testing showed normal levels. OBJECTIVE To characterize S1118F-CFTR mutation at a molecular level to help understand the associated CF-phenotype. METHODS Molecular characterization of S1118F-CFTR mutant was studied in HEK-293 cells at 37 degrees C. Various biochemical methods such as Western blotting, real-time PCR, Pulse chase labeling and iodide efflux assay were employed. RESULTS S1118F-CFTR makes less than 10-15% of mature CFTR (band C) compared to WT-CFTR. The mRNA levels of S1118F-CFTR and WT-CFTR are comparable. S1118F-CFTR is functional but shows about 10-15% of WT-CFTR activity. S1118F-CFTR shows impaired maturation and CF-correctors can increase the amount of mature and functional CFTR by three- to fourfold. CONCLUSION S1118F-CFTR shows impaired maturation and an individual with S1118F-CFTR paired with DeltaF508-CFTR exhibits atypical CF symptoms with intermediate sweat chloride level and meconium ileus despite documented pancreatic sufficiency.
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Affiliation(s)
- Himabindu Penmatsa
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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Grove DE, Rosser MFN, Ren HY, Naren AP, Cyr DM. Mechanisms for rescue of correctable folding defects in CFTRDelta F508. Mol Biol Cell 2009; 20:4059-69. [PMID: 19625452 DOI: 10.1091/mbc.e08-09-0929] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Premature degradation of CFTRDeltaF508 causes cystic fibrosis (CF). CFTRDeltaF508 folding defects are conditional and folding correctors are being developed as CF therapeutics. How the cellular environment impacts CFTRDeltaF508 folding efficiency and the identity of CFTRDeltaF508's correctable folding defects is unclear. We report that inactivation of the RMA1 or CHIP ubiquitin ligase permits a pool of CFTRDeltaF508 to escape the endoplasmic reticulum. Combined RMA1 or CHIP inactivation and Corr-4a treatment enhanced CFTRDeltaF508 folding to 3-7-fold greater levels than those elicited by Corr-4a. Some, but not all, folding defects in CFTRDeltaF508 are correctable. CHIP and RMA1 recognize different regions of CFTR and a large pool of nascent CFTRDeltaF508 is ubiquitinated by RMA1 before Corr-4a action. RMA1 recognizes defects in CFTRDeltaF508 related to misassembly of a complex that contains MSD1, NBD1, and the R-domain. Corr-4a acts on CFTRDeltaF508 after MSD2 synthesis and was ineffective at rescue of DeltaF508 dependent folding defects in amino-terminal regions. In contrast, misfolding caused by the rare CF-causing mutation V232D in MSD1 was highly correctable by Corr-4a. Overall, correction of folding defects recognized by RMA1 and/or global modulation of ER quality control has the potential to increase CFTRDeltaF508 folding and provide a therapeutic approach for CF.
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Affiliation(s)
- Diane E Grove
- Department of Cell and Developmental Biology and the UNC-Cystic Fibrosis Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Jurkuvenaite A, Chen L, Bartoszewski R, Goldstein R, Bebok Z, Matalon S, Collawn JF. Functional stability of rescued delta F508 cystic fibrosis transmembrane conductance regulator in airway epithelial cells. Am J Respir Cell Mol Biol 2009; 42:363-72. [PMID: 19502384 DOI: 10.1165/rcmb.2008-0434oc] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The most common mutation in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene, Delta F508, results in the production of a misfolded protein that is rapidly degraded. The mutant protein is temperature sensitive, and prior studies indicate that the low-temperature-rescued channel is poorly responsive to physiological stimuli, and is rapidly degraded from the cell surface at 37 degrees C. In the present studies, we tested the effect of a recently characterized pharmacological corrector, 2-(5-chloro-2-methoxy-phenylamino)-4'-methyl-[4,5'bithiazolyl-2'-yl]-phenyl-methanone (corr-4a), on cell surface stability and function of the low-temperature-rescued Delta F508 CFTR. We demonstrate that corr-4a significantly enhanced the protein stability of rescued Delta F508 CFTR for up to 12 hours at 37 degrees C (P < 0.05). Using firefly luciferase-based reporters to investigate the mechanisms by which low temperature and corr-4a enhance rescue, we found that low-temperature treatment inhibited proteasomal function, whereas corr-4a treatment inhibited the E1-E3 ubiquitination pathway. Ussing chamber studies indicated that corr-4a increased the cAMP-mediated Delta F508 CFTR response by 61% at 6 hours (P < 0.05), but not at later time points. However, addition of the CFTR channel activator, 4-methyl-2-(5-phenyl-1H-pyrazol-3-yl)-phenol, significantly augmented cAMP-stimulated currents, revealing that the biochemically detectable cell surface Delta F508 CFTR could be stimulated under the right conditions. Our studies demonstrate that stabilizing rescued Delta F508 CFTR was not sufficient to obtain maximal Delta F508 CFTR function in airway epithelial cells. These results strongly support the idea that maximal correction of Delta F508 CFTR requires a chemical corrector that: (1) promotes folding and exit from the endoplasmic reticulum; (2) enhances surface stability; and (3) improves channel activity.
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Affiliation(s)
- Asta Jurkuvenaite
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Conn PM, Janovick JA. Drug development and the cellular quality control system. Trends Pharmacol Sci 2009; 30:228-33. [DOI: 10.1016/j.tips.2009.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 02/11/2009] [Accepted: 02/12/2009] [Indexed: 01/01/2023]
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