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Meng Z, Capel RA, Bose SJ, Bosch E, de Jong S, Planque R, Galione A, Burton RAB, Bueno-Orovio A. Lysosomal calcium loading promotes spontaneous calcium release by potentiating ryanodine receptors. Biophys J 2023; 122:3044-3059. [PMID: 37329137 PMCID: PMC10432190 DOI: 10.1016/j.bpj.2023.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 05/03/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023] Open
Abstract
Spontaneous calcium release by ryanodine receptors (RyRs) due to intracellular calcium overload results in delayed afterdepolarizations, closely associated with life-threatening arrhythmias. In this regard, inhibiting lysosomal calcium release by two-pore channel 2 (TPC2) knockout has been shown to reduce the incidence of ventricular arrhythmias under β-adrenergic stimulation. However, mechanistic investigations into the role of lysosomal function on RyR spontaneous release remain missing. We investigate the calcium handling mechanisms by which lysosome function modulates RyR spontaneous release, and determine how lysosomes are able to mediate arrhythmias by its influence on calcium loading. Mechanistic studies were conducted using a population of biophysically detailed mouse ventricular models including for the first time modeling of lysosomal function, and calibrated by experimental calcium transients modulated by TPC2. We demonstrate that lysosomal calcium uptake and release can synergistically provide a pathway for fast calcium transport, by which lysosomal calcium release primarily modulates sarcoplasmic reticulum calcium reuptake and RyR release. Enhancement of this lysosomal transport pathway promoted RyR spontaneous release by elevating RyR open probability. In contrast, blocking either lysosomal calcium uptake or release revealed an antiarrhythmic impact. Under conditions of calcium overload, our results indicate that these responses are strongly modulated by intercellular variability in L-type calcium current, RyR release, and sarcoplasmic reticulum calcium-ATPase reuptake. Altogether, our investigations identify that lysosomal calcium handling directly influences RyR spontaneous release by regulating RyR open probability, suggesting antiarrhythmic strategies and identifying key modulators of lysosomal proarrhythmic action.
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Affiliation(s)
- Zhaozheng Meng
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Rebecca A Capel
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Samuel J Bose
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Erik Bosch
- Department of Mathematics, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Sophia de Jong
- Department of Mathematics, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Robert Planque
- Department of Mathematics, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Rebecca A B Burton
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom.
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Bose SJ, Read MJ, Akerman E, Capel RA, Ayagama T, Russell A, Terrar DA, Zaccolo M, Burton RAB. Inhibition of adenylyl cyclase 1 by ST034307 inhibits IP3-evoked changes in sino-atrial node beat rate. Front Pharmacol 2022; 13:951897. [PMID: 36105228 PMCID: PMC9465815 DOI: 10.3389/fphar.2022.951897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Atrial arrhythmias, such as atrial fibrillation (AF), are a major mortality risk and a leading cause of stroke. The IP3 signalling pathway has been proposed as an atrial-specific target for AF therapy, and atrial IP3 signalling has been linked to the activation of calcium sensitive adenylyl cyclases AC1 and AC8. We investigated the involvement of AC1 in the response of intact mouse atrial tissue and isolated guinea pig atrial and sino-atrial node (SAN) cells to the α-adrenoceptor agonist phenylephrine (PE) using the selective AC1 inhibitor ST034307. The maximum rate change of spontaneously beating mouse right atrial tissue exposed to PE was reduced from 14.5% to 8.2% (p = 0.005) in the presence of 1 μM ST034307, whereas the increase in tension generated in paced left atrial tissue in the presence of PE was not inhibited by ST034307 (Control = 14.2%, ST034307 = 16.3%; p > 0.05). Experiments were performed using isolated guinea pig atrial and SAN cells loaded with Fluo-5F-AM to record changes in calcium transients (CaT) generated by 10 μM PE in the presence and absence of 1 μM ST034307. ST034307 significantly reduced the beating rate of SAN cells (0.34-fold decrease; p = 0.003) but did not inhibit changes in CaT amplitude in response to PE in atrial cells. The results presented here demonstrate pharmacologically the involvement of AC1 in the downstream response of atrial pacemaker activity to α-adrenoreceptor stimulation and IP3R calcium release.
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Affiliation(s)
- Samuel J. Bose
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Matthew J. Read
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Emily Akerman
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Rebecca A. Capel
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Thamali Ayagama
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Angela Russell
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Derek A. Terrar
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Rebecca A. B. Burton
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
- *Correspondence: Rebecca A. B. Burton,
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Ayagama T, Bose SJ, Capel RA, Priestman DA, Berridge G, Fischer R, Galione A, Platt FM, Kramer H, Burton RA. A modified density gradient proteomic-based method to analyze endolysosomal proteins in cardiac tissue. iScience 2021; 24:102949. [PMID: 34466782 PMCID: PMC8384914 DOI: 10.1016/j.isci.2021.102949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 03/04/2021] [Accepted: 08/02/2021] [Indexed: 11/22/2022] Open
Abstract
The importance of lysosomes in cardiac physiology and pathology is well established, and evidence for roles in calcium signaling is emerging. We describe a label-free proteomics method suitable for small cardiac tissue biopsies based on density-separated fractionation, which allows study of endolysosomal (EL) proteins. Density gradient fractions corresponding to tissue lysate; sarcoplasmic reticulum (SR), mitochondria (Mito) (1.3 g/mL); and EL with negligible contamination from SR or Mito (1.04 g/mL) were analyzed using Western blot, enzyme activity assay, and liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis (adapted discontinuous Percoll and sucrose differential density gradient). Kyoto Encyclopedia of Genes and Genomes, Reactome, Panther, and Gene Ontology pathway analysis showed good coverage of RAB proteins and lysosomal cathepsins (including cardiac-specific cathepsin D) in the purified EL fraction. Significant EL proteins recovered included catalytic activity proteins. We thus present a comprehensive protocol and data set of guinea pig atrial EL organelle proteomics using techniques also applicable for non-cardiac tissue.
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Affiliation(s)
- Thamali Ayagama
- University of Oxford, Department of Pharmacology, Oxford, OX1 3QT UK
| | - Samuel J. Bose
- University of Oxford, Department of Pharmacology, Oxford, OX1 3QT UK
| | - Rebecca A. Capel
- University of Oxford, Department of Pharmacology, Oxford, OX1 3QT UK
| | | | - Georgina Berridge
- Target Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
| | - Roman Fischer
- Target Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
| | - Antony Galione
- University of Oxford, Department of Pharmacology, Oxford, OX1 3QT UK
| | - Frances M. Platt
- University of Oxford, Department of Pharmacology, Oxford, OX1 3QT UK
| | - Holger Kramer
- Biological Mass Spectrometry and Proteomics Facility, MRC London Institute of Medical Sciences, Imperial College London, London, W12 0NN UK
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Capel RA, Bose SJ, Collins TP, Rajasundaram S, Ayagama T, Zaccolo M, Burton RAB, Terrar DA. IP 3-mediated Ca 2+ release regulates atrial Ca 2+ transients and pacemaker function by stimulation of adenylyl cyclases. Am J Physiol Heart Circ Physiol 2020; 320:H95-H107. [PMID: 33064562 PMCID: PMC7864251 DOI: 10.1152/ajpheart.00380.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Inositol trisphosphate (IP3) is a Ca2+-mobilizing second messenger shown to modulate atrial muscle contraction and is thought to contribute to atrial fibrillation. Cellular pathways underlying IP3 actions in cardiac tissue remain poorly understood, and the work presented here addresses the question whether IP3-mediated Ca2+ release from the sarcoplasmic reticulum is linked to adenylyl cyclase activity including Ca2+-stimulated adenylyl cyclases (AC1 and AC8) that are selectively expressed in atria and sinoatrial node (SAN). Immunocytochemistry in guinea pig atrial myocytes identified colocalization of type 2 IP3 receptors with AC8, while AC1 was located in close vicinity. Intracellular photorelease of IP3 by UV light significantly enhanced the amplitude of the Ca2+ transient (CaT) evoked by electrical stimulation of atrial myocytes (31 ± 6% increase 60 s after photorelease, n = 16). The increase in CaT amplitude was abolished by inhibitors of adenylyl cyclases (MDL-12,330) or protein kinase A (H89), showing that cAMP signaling is required for this effect of photoreleased IP3. In mouse, spontaneously beating right atrial preparations, phenylephrine, an α-adrenoceptor agonist with effects that depend on IP3-mediated Ca2+ release, increased the maximum beating rate by 14.7 ± 0.5%, n = 10. This effect was substantially reduced by 2.5 µmol/L 2-aminoethyl diphenylborinate and abolished by a low dose of MDL-12,330, observations which are again consistent with a functional interaction between IP3 and cAMP signaling involving Ca2+ stimulation of adenylyl cyclases in the SAN pacemaker. Understanding the interaction between IP3 receptor pathways and Ca2+-stimulated adenylyl cyclases provides important insights concerning acute mechanisms for initiation of atrial arrhythmias. NEW & NOTEWORTHY This study provides evidence supporting the proposal that IP3 signaling in cardiac atria and sinoatrial node involves stimulation of Ca2+-activated adenylyl cyclases (AC1 and AC8) by IP3-evoked Ca2+ release from junctional sarcoplasmic reticulum. AC8 and IP3 receptors are shown to be located close together, while AC1 is nearby. Greater understanding of these novel aspects of the IP3 signal transduction mechanism is important for future study in atrial physiology and pathophysiology, particularly atrial fibrillation.
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Affiliation(s)
- Rebecca A Capel
- Department of Pharmacology, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Samuel J Bose
- Department of Pharmacology, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Thomas P Collins
- Department of Pharmacology, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Skanda Rajasundaram
- Department of Pharmacology, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Thamali Ayagama
- Department of Pharmacology, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Rebecca-Ann Beatrice Burton
- Department of Pharmacology, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Derek A Terrar
- Department of Pharmacology, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
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Burton RAB, Tomek J, Ambrosi CM, Larsen HE, Sharkey AR, Capel RA, Corbett AD, Bilton S, Klimas A, Stephens G, Cremer M, Bose SJ, Li D, Gallone G, Herring N, Mann EO, Kumar A, Kramer H, Entcheva E, Paterson DJ, Bub G. Optical Interrogation of Sympathetic Neuronal Effects on Macroscopic Cardiomyocyte Network Dynamics. iScience 2020; 23:101334. [PMID: 32674058 PMCID: PMC7363704 DOI: 10.1016/j.isci.2020.101334] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 05/12/2020] [Accepted: 06/26/2020] [Indexed: 12/21/2022] Open
Abstract
Cardiac stimulation via sympathetic neurons can potentially trigger arrhythmias. We present approaches to study neuron-cardiomyocyte interactions involving optogenetic selective probing and all-optical electrophysiology to measure activity in an automated fashion. Here we demonstrate the utility of optical interrogation of sympathetic neurons and their effects on macroscopic cardiomyocyte network dynamics to address research targets such as the effects of adrenergic stimulation via the release of neurotransmitters, the effect of neuronal numbers on cardiac behavior, and the applicability of optogenetics in mechanistic in vitro studies. As arrhythmias are emergent behaviors that involve the coordinated activity of millions of cells, we image at macroscopic scales to capture complex dynamics. We show that neurons can both decrease and increase wave stability and re-entrant activity in culture depending on their induced activity-a finding that may help us understand the often conflicting results seen in experimental and clinical studies.
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Affiliation(s)
- Rebecca-Ann B Burton
- University of Oxford, Department of Pharmacology, Mansfield Road, Oxford OX1 3QT, UK; University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK.
| | - Jakub Tomek
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Christina M Ambrosi
- The George Washington University, Department of Biomedical Engineering, Washington, DC 20052, USA
| | - Hege E Larsen
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Amy R Sharkey
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Rebecca A Capel
- University of Oxford, Department of Pharmacology, Mansfield Road, Oxford OX1 3QT, UK
| | | | - Samuel Bilton
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Aleksandra Klimas
- The George Washington University, Department of Biomedical Engineering, Washington, DC 20052, USA
| | - Guy Stephens
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Maegan Cremer
- University of Oxford, Department of Pharmacology, Mansfield Road, Oxford OX1 3QT, UK
| | - Samuel J Bose
- University of Oxford, Department of Pharmacology, Mansfield Road, Oxford OX1 3QT, UK
| | - Dan Li
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Giuseppe Gallone
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK; Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
| | - Neil Herring
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Edward O Mann
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Abhinav Kumar
- University of Oxford, Department of Biochemistry, Glycobiology Institute, Oxford, UK
| | - Holger Kramer
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Emilia Entcheva
- The George Washington University, Department of Biomedical Engineering, Washington, DC 20052, USA
| | - David J Paterson
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK
| | - Gil Bub
- University of Oxford, Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, Parks Road, Oxford OX1 3PT, UK; McGill University, Department of Physiology, McIntyre Medical Sciences Building, Room 1128, 3655 Promenade Sir William Osler, Montréal, QC H3G 1Y6, Canada.
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6
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Sigalas C, Cremer M, Winbo A, Bose SJ, Ashton JL, Bub G, Montgomery JM, Burton RAB. Combining tissue engineering and optical imaging approaches to explore interactions along the neuro-cardiac axis. R Soc Open Sci 2020; 7:200265. [PMID: 32742694 PMCID: PMC7353978 DOI: 10.1098/rsos.200265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/27/2020] [Indexed: 05/05/2023]
Abstract
Interactions along the neuro-cardiac axis are being explored with regard to their involvement in cardiac diseases, including catecholaminergic polymorphic ventricular tachycardia, hypertension, atrial fibrillation, long QT syndrome and sudden death in epilepsy. Interrogation of the pathophysiology and pathogenesis of neuro-cardiac diseases in animal models present challenges resulting from species differences, phenotypic variation, developmental effects and limited availability of data relevant at both the tissue and cellular level. By contrast, tissue-engineered models containing cardiomyocytes and peripheral sympathetic and parasympathetic neurons afford characterization of cellular- and tissue-level behaviours while maintaining precise control over developmental conditions, cellular genotype and phenotype. Such approaches are uniquely suited to long-term, high-throughput characterization using optical recording techniques with the potential for increased translational benefit compared to more established techniques. Furthermore, tissue-engineered constructs provide an intermediary between whole animal/tissue experiments and in silico models. This paper reviews the advantages of tissue engineering methods of multiple cell types and optical imaging techniques for the characterization of neuro-cardiac diseases.
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Affiliation(s)
| | - Maegan Cremer
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Annika Winbo
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Department of Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand
| | - Samuel J. Bose
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Jesse L. Ashton
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Gil Bub
- Department of Physiology, McGill University, Montreal, Canada
| | | | - Rebecca A. B. Burton
- Department of Pharmacology, University of Oxford, Oxford, UK
- Author for correspondence: Rebecca A. B. Burton e-mail:
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Bose SJ, Bijvelds MJC, Wang Y, Liu J, Cai Z, Bot AGM, de Jonge HR, Sheppard DN. Differential thermostability and response to cystic fibrosis transmembrane conductance regulator potentiators of human and mouse F508del-CFTR. Am J Physiol Lung Cell Mol Physiol 2019; 317:L71-L86. [PMID: 30969810 PMCID: PMC6689747 DOI: 10.1152/ajplung.00034.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Cross-species comparative studies have highlighted differences between human and mouse cystic fibrosis transmembrane conductance regulator (CFTR), the epithelial Cl- channel defective in cystic fibrosis (CF). Here, we compare the impact of the most common CF mutation F508del on the function of human and mouse CFTR heterologously expressed in mammalian cells and their response to CFTR modulators using the iodide efflux and patch-clamp techniques. Once delivered to the plasma membrane, human F508del-CFTR exhibited a severe gating defect characterized by infrequent channel openings and was thermally unstable, deactivating within minutes at 37°C. By contrast, the F508del mutation was without effect on the gating pattern of mouse CFTR, and channel activity demonstrated thermostability at 37°C. Strikingly, at all concentrations tested, the clinically approved CFTR potentiator ivacaftor was without effect on the mouse F508del-CFTR Cl- channel. Moreover, eight CFTR potentiators, including ivacaftor, failed to generate CFTR-mediated iodide efflux from CHO cells expressing mouse F508del-CFTR. However, they all produced CFTR-mediated iodide efflux with human F508del-CFTR-expressing CHO cells, while fifteen CFTR correctors rescued the plasma membrane expression of both human and mouse F508del-CFTR. Interestingly, the CFTR potentiator genistein enhanced CFTR-mediated iodide efflux from CHO cells expressing either human or mouse F508del-CFTR, whereas it only potentiated human F508del-CFTR Cl- channels in cell-free membrane patches, suggesting that its action on mouse F508del-CFTR is indirect. Thus, the F508del mutation has distinct effects on human and mouse CFTR Cl- channels.
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Affiliation(s)
- Samuel J Bose
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Marcel J C Bijvelds
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center , Rotterdam , The Netherlands
| | - Yiting Wang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Jia Liu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Zhiwei Cai
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Alice G M Bot
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center , Rotterdam , The Netherlands
| | - Hugo R de Jonge
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center , Rotterdam , The Netherlands
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
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8
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Chen X, Zhu S, Zhenin M, Xu W, Bose SJ, Wong MPF, Leung GPH, Senderowitz H, Chen JH. A defective flexible loop contributes to the processing and gating defects of the predominant cystic fibrosis-causing mutation. FASEB J 2019; 33:5126-5142. [PMID: 30668920 DOI: 10.1096/fj.201801218rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
People with the genetic disease cystic fibrosis (CF) often carry a deletion mutation ΔF508 on the gene encoding the CF transmembrane conductance regulator (CFTR) Cl- channel. This mutation greatly reduces the CFTR maturation process and slows the channel opening rate. Here, we investigate whether residues near F508 contribute to these defects in ΔF508-CFTR. Most deletion mutations, but not alanine substitutions, of individual residues from positions 503 to 513 impaired CFTR maturation. Interestingly, only protein processing of ΔY512-CFTR, like that of ΔF508-CFTR, was greatly improved by low-temperature culture at 27°C or small-molecule corrector C18. The 2 mutant Cl- channels were equally slow to open, suggesting that they may share common structural flaws. Studies on the H3-H4 loop that links residues F508 and Y512 demonstrate that G509A/V510G mutations, moving G509 1 position backward in the loop, markedly enhanced ΔF508-CFTR maturation and opening rate while promoting protein stability and persistence of the H3 helix in ΔF508 nucleotide-binding domain 1. Moreover, V510A/S511A mutations noticeably increased ΔY512-CFTR maturation at 27°C and its opening rate. Thus, loop abnormalities may contribute to ΔF508- and ΔY512-CFTR defects. Importantly, correcting defects from G509 displacement in ΔF508-CFTR may offer a new avenue for drug discovery and CF treatments.-Chen, X., Zhu, S., Zhenin, M., Xu, W., Bose, S. J., Wong, M. P.-F., Leung, G. P. H., Senderowitz, H., Chen, J.-H. A defective flexible loop contributes to the processing and gating defects of the predominant cystic fibrosis-causing mutation.
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Affiliation(s)
- Xinying Chen
- School of Biomedical Sciences, University of Hong Kong, Hong Kong.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, China
| | - Siyu Zhu
- School of Biomedical Sciences, University of Hong Kong, Hong Kong.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, China
| | - Michael Zhenin
- Department of Chemistry, Bar Ilan University, Ramat-Gan, Israel
| | - Weiyi Xu
- School of Biomedical Sciences, University of Hong Kong, Hong Kong.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, China
| | - Samuel J Bose
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom; and
| | - Molly Pik-Fan Wong
- School of Biomedical Sciences, University of Hong Kong, Hong Kong.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, China
| | - George P H Leung
- Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong, China
| | | | - Jeng-Haur Chen
- School of Biomedical Sciences, University of Hong Kong, Hong Kong.,The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, China
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