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Strupp M, Churchill GC, Naumann I, Mansmann U, Al Tawil A, Golentsova A, Goldschagg N. Examination of betahistine bioavailability in combination with the monoamine oxidase B inhibitor, selegiline, in humans-a non-randomized, single-sequence, two-period titration, open label single-center phase 1 study (PK-BeST). Front Neurol 2023; 14:1271640. [PMID: 37920833 PMCID: PMC10619746 DOI: 10.3389/fneur.2023.1271640] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/04/2023] [Indexed: 11/04/2023] Open
Abstract
Background Betahistine was registered in Europe in the 1970s and approved in more than 80 countries as a first-line treatment for Menière's disease. It has been administered to more than 150 million patients. However, according to a Cochrane systematic review of betahistine and recent meta-analyses, there is insufficient evidence to say whether betahistine has any effect in the currently approved dosages of up to 48 mg/d. A combination with the monoamine oxidase B (MAO-B) inhibitor, selegiline, may increase the bioavailability of betahistine to levels similar to the well-established combination of L-DOPA with carbidopa or benserazide in the treatment of Parkinson's disease. We investigated the effect of selegiline on betahistine pharmacokinetics and the safety of the combination in humans. Methods In an investigator-initiated prospective, non-randomized, single-sequence, two-period titration, open label single-center phase 1 study, 15 healthy volunteers received three single oral dosages of betahistine (24, 48, and 96 mg in this sequence with at least 2 days' washout period) without and with selegiline (5 mg/d with a loading period of 7 days). Betahistine serum concentrations were measured over a period of 240 min at eight time points (area under the curve, AUC0-240 min). This trial is registered with EudraCT (2019-002610-39) and ClinicalTrials.gov. Findings In all three single betahistine dosages, selegiline increased the betahistine bioavailability about 80- to 100-fold. For instance, the mean (±SD) of the area under curve for betahistine 48 mg alone was 0.64 (+/-0.47) h*ng/mL and for betahistine plus selegiline 53.28 (+/-37.49) h*ng/mL. The half-life time of around 30 min was largely unaffected, except for the 24 mg betahistine dosage. In total, 14 mild adverse events were documented. Interpretation This phase 1 trial shows that the MAO-B inhibitor selegiline increases betahistine bioavailability by a factor of about 80 to 100. No safety concerns were detected. Whether the increased bioavailability has an impact on the preventive treatment of Menière's disease, acute vestibular syndrome, or post-BPPV residual dizziness has to be evaluated in placebo-controlled trials. Clinical trial registration https://clinicaltrials.gov/study/NCT05938517?intr=betahistine%20and%20selegiline&rank=1, identifier: NCT05938517.
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Affiliation(s)
- Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, LMU University Hospital, LMU Munich, Munich, Germany
| | - Grant C. Churchill
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Ivonne Naumann
- Department of Neurology and German Center for Vertigo and Balance Disorders, LMU University Hospital, LMU Munich, Munich, Germany
| | - Ulrich Mansmann
- Department of Medical Information Sciences, Biometry and Epidemiology, Ludwig Maximilians University, Munich, Germany
| | - Amani Al Tawil
- Department of Medical Information Sciences, Biometry and Epidemiology, Ludwig Maximilians University, Munich, Germany
| | - Anastasia Golentsova
- Department of Neurology and German Center for Vertigo and Balance Disorders, LMU University Hospital, LMU Munich, Munich, Germany
| | - Nicolina Goldschagg
- Department of Neurology and German Center for Vertigo and Balance Disorders, LMU University Hospital, LMU Munich, Munich, Germany
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Fields T, M Bremova T, Billington I, Churchill GC, Evans W, Fields C, Galione A, Kay R, Mathieson T, Martakis K, Patterson M, Platt F, Factor M, Strupp M. N-acetyl-L-leucine for Niemann-Pick type C: a multinational double-blind randomized placebo-controlled crossover study. Trials 2023; 24:361. [PMID: 37248494 DOI: 10.1186/s13063-023-07399-6] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 05/22/2023] [Indexed: 05/31/2023] Open
Abstract
BACKGROUND Niemann-Pick disease type C (NPC) is a rare autosomal recessive neurodegenerative lysosomal disease characterized by multiple symptoms such as progressive cerebellar ataxia and cognitive decline. The modified amino acid N-acetyl-leucine has been associated with positive symptomatic and neuroprotective, disease-modifying effects in various studies, including animal models of NPC, observational clinical case studies, and a multinational, rater-blinded phase IIb clinical trial. Here, we describe the development of a study protocol (Sponsor Code "IB1001-301") for the chronic treatment of symptoms in adult and pediatric patients with NPC. METHODS This multinational double-blind randomized placebo-controlled crossover phase III study will enroll patients with a genetically confirmed diagnosis of NPC patients aged 4 years and older across 16 trial sites. Patients are assessed during a baseline period and then randomized (1:1) to one of two treatment sequences: IB1001 followed by placebo or vice versa. Each sequence consists of a 12-week treatment period. The primary efficacy endpoint is based on the Scale for the Assessment and Rating of Ataxia, and secondary outcomes include cerebellar functional rating scales, clinical global impression, and quality of life assessments. DISCUSSION Pre-clinical as well as observational and phase IIb clinical trials have previously demonstrated that IB1001 rapidly improved symptoms, functioning, and quality of life for pediatric and adult NPC patients and is safe and well tolerated. In this placebo-controlled cross-over trial, the risk/benefit profile of IB1001 for NPC will be evaluated. It will also give information about the applicability of IB1001 as a therapeutic paradigm for other rare and common neurological disorders. TRIAL REGISTRATIONS The trial (IB1001-301) has been registered at www. CLINICALTRIALS gov (NCT05163288) and www.clinicaltrialsregister.eu (EudraCT: 2021-005356-10). Registered on 20 December 2021.
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Affiliation(s)
- T Fields
- IntraBio Ltd, Begbroke Science Park, Begroke Hill, Woodstock Road, Oxford, OX5 1PF, UK.
| | - T M Bremova
- Department of Neurology, Inselspital, University Hospital Bern, and University of Bern, Bern, Switzerland
| | - I Billington
- IntraBio Ltd, Begbroke Science Park, Begroke Hill, Woodstock Road, Oxford, OX5 1PF, UK
| | - G C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - W Evans
- Niemann-Pick UK, Suite 2, Vermont House, Concord, Tyne and Wear, Washington, NE37 2SQ, UK
- Primary Care Stratified Medicine (PRISM), Division of Primary Care, University of Nottingham, Nottingham, UK
| | - C Fields
- IntraBio Ltd, Begbroke Science Park, Begroke Hill, Woodstock Road, Oxford, OX5 1PF, UK
| | - A Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - R Kay
- RK Statistics, Brook House, Mesne Lane, Bakewell, DE45 1AL, UK
| | - T Mathieson
- Niemann-Pick UK, Suite 2, Vermont House, Concord, Tyne and Wear, Washington, NE37 2SQ, UK
- RK Statistics, Brook House, Mesne Lane, Bakewell, DE45 1AL, UK
| | - K Martakis
- Department of Pediatric Neurology, University Children's Hospital (UKGM) and Medical Faculty, Justus Liebig University of Giessen, Giessen, Germany
| | - M Patterson
- Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - F Platt
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - M Factor
- IntraBio Ltd, Begbroke Science Park, Begroke Hill, Woodstock Road, Oxford, OX5 1PF, UK
| | - M Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Ludwig Maximilians University, Munich, Germany
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Abuhammad A, Laurieri N, Rice A, Lowe ED, Singh N, Naser SM, Ratrout SS, Churchill GC. Structural and biochemical analysis of human inositol monophosphatase-1 inhibition by ebselen. J Biomol Struct Dyn 2023; 41:14036-14048. [PMID: 36762717 DOI: 10.1080/07391102.2023.2176925] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/30/2023] [Indexed: 02/11/2023]
Abstract
Bipolar disorder is a major psychiatric disorder associated with cognitive impairment and a high suicide rate. Frontline therapy for this condition includes lithium (Li+)-containing treatments that can exert severe side effects. One target of Li+ is inositol monophosphatase-1 (IMPase1); inhibition of IMPase1 through small-molecule compounds may provide an alternative treatment for bipolar disorder. One such compound is the anti-inflammatory drug ebselen, which is well tolerated and safe; however, ebselen's exact mechanism of action in IMPase1 inhibition is not fully understood, preventing rational design of IMPase1 inhibitors. To fill this gap, we performed crystallographic and biochemical studies to investigate how ebselen inhibits IMPase1. We obtained a structure of IMPase1 in space group P21 after treatment with ebselen that revealed three key active-site loops (residues 33-44, 70-79, and 161-165) that are either disordered or in multiple conformations, supporting a hypothesis whereby dynamic conformational changes may be important for catalysis and ebselen inhibition. Using the thermal shift assay, we confirmed that ebselen significantly destabilizes the enzyme. Molecular docking suggests that ebselen could bind in the vicinity of His217. Investigation of the role of IMPase1 residues His217 and Cys218 suggests that inhibition of IMPase1 by ebselen may not be mediated via covalent modification of the active-site cysteine (Cys218) and is not affected by the covalent modification of other cysteine residues in the structure. Our results suggest that effects previously ascribed to ebselen-dependent inhibition likely result from disruption of essential active-site architecture, preventing activation of the IMPase1-Mg2+ complex.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Areej Abuhammad
- Department of Pharmaceutical Sciences, School of Pharmacy, The University of Jordan, Amman, Jordan
| | - Nicola Laurieri
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Alistair Rice
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Edward D Lowe
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Nisha Singh
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Saleem M Naser
- Research and Development Department, APIs Division, Hikma Pharmaceutical Co. Ltd, Amman, Jordan
| | - Samer S Ratrout
- Research and Development Department, APIs Division, Hikma Pharmaceutical Co. Ltd, Amman, Jordan
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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Quinn TM, Gaughan EE, Bruce A, Antonelli J, O'Connor R, Li F, McNamara S, Koch O, MacKintosh C, Dockrell D, Walsh T, Blyth KG, Church C, Schwarze J, Boz C, Valanciute A, Burgess M, Emanuel P, Mills B, Rinaldi G, Hardisty G, Mills R, Findlay EG, Jabbal S, Duncan A, Plant S, Marshall ADL, Young I, Russell K, Scholefield E, Nimmo AF, Nazarov IB, Churchill GC, McCullagh JSO, Ebrahimi KH, Ferrett C, Templeton K, Rannard S, Owen A, Moore A, Finlayson K, Shankar-Hari M, Norrie J, Parker RA, Akram AR, Anthony DC, Dear JW, Hirani N, Dhaliwal K. Randomised controlled trial of intravenous nafamostat mesylate in COVID pneumonitis: Phase 1b/2a experimental study to investigate safety, Pharmacokinetics and Pharmacodynamics. EBioMedicine 2022; 76:103856. [PMID: 35152152 PMCID: PMC8831100 DOI: 10.1016/j.ebiom.2022.103856] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/12/2022] [Accepted: 01/17/2022] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Many repurposed drugs have progressed rapidly to Phase 2 and 3 trials in COVID19 without characterisation of Pharmacokinetics /Pharmacodynamics including safety data. One such drug is nafamostat mesylate. METHODS We present the findings of a phase Ib/IIa open label, platform randomised controlled trial of intravenous nafamostat in hospitalised patients with confirmed COVID-19 pneumonitis. Patients were assigned randomly to standard of care (SoC), nafamostat or an alternative therapy. Nafamostat was administered as an intravenous infusion at a dose of 0.2 mg/kg/h for a maximum of seven days. The analysis population included those who received any dose of the trial drug and all patients randomised to SoC. The primary outcomes of our trial were the safety and tolerability of intravenous nafamostat as an add on therapy for patients hospitalised with COVID-19 pneumonitis. FINDINGS Data is reported from 42 patients, 21 of which were randomly assigned to receive intravenous nafamostat. 86% of nafamostat-treated patients experienced at least one AE compared to 57% of the SoC group. The nafamostat group were significantly more likely to experience at least one AE (posterior mean odds ratio 5.17, 95% credible interval (CI) 1.10 - 26.05) and developed significantly higher plasma creatinine levels (posterior mean difference 10.57 micromol/L, 95% CI 2.43-18.92). An average longer hospital stay was observed in nafamostat patients, alongside a lower rate of oxygen free days (rate ratio 0.55-95% CI 0.31-0.99, respectively). There were no other statistically significant differences in endpoints between nafamostat and SoC. PK data demonstrated that intravenous nafamostat was rapidly broken down to inactive metabolites. We observed no significant anticoagulant effects in thromboelastometry. INTERPRETATION In hospitalised patients with COVID-19, we did not observe evidence of anti-inflammatory, anticoagulant or antiviral activity with intravenous nafamostat, and there were additional adverse events. FUNDING DEFINE was funded by LifeArc (an independent medical research charity) under the STOPCOVID award to the University of Edinburgh. We also thank the Oxford University COVID-19 Research Response Fund (BRD00230).
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Affiliation(s)
- Tom M Quinn
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK; Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | - Erin E Gaughan
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK; Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | - Annya Bruce
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Jean Antonelli
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Richard O'Connor
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Feng Li
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Sarah McNamara
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Oliver Koch
- Regional Infectious Disease Unit, NHS Lothian, UK
| | | | - David Dockrell
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK; Regional Infectious Disease Unit, NHS Lothian, UK
| | - Timothy Walsh
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK; Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | - Kevin G Blyth
- Institute of Cancer Sciences, University of Glasgow, UK
| | - Colin Church
- Department of Respiratory Medicine, Queen Elizabeth University Hospital, NHS Greater Glasgow and Clyde Health Board, Glasgow, UK
| | - Jürgen Schwarze
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Cecilia Boz
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Asta Valanciute
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Matthew Burgess
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Philip Emanuel
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Bethany Mills
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Giulia Rinaldi
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Gareth Hardisty
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Ross Mills
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Emily Gwyer Findlay
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Sunny Jabbal
- Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | | | - Sinéad Plant
- Regional Infectious Disease Unit, NHS Lothian, UK
| | - Adam D L Marshall
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK; Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | - Irene Young
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Kay Russell
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Emma Scholefield
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Alastair F Nimmo
- Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | - Islom B Nazarov
- Latus Therapeutics, Oxford, UK; Department of Pharmacology, University of Oxford, Oxford, UK
| | | | | | | | - Colin Ferrett
- Department of Radiology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Kate Templeton
- Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | - Steve Rannard
- Centre of Excellence for Long-acting Therapeutics, Materials Innovation Factory and Department of Pharmacology and Therapeutics, University of Liverpool, UK
| | - Andrew Owen
- Centre of Excellence for Long-acting Therapeutics, Materials Innovation Factory and Department of Pharmacology and Therapeutics, University of Liverpool, UK
| | - Anne Moore
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Keith Finlayson
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Manu Shankar-Hari
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK
| | - John Norrie
- Centre for Cardiovascular Science, Queen's Medical Research Institute, Bioquarter, University of Edinburgh, Edinburgh, UK
| | - Richard A Parker
- Edinburgh Clinical Trials Unit (ECTU), Usher Institute, University of Edinburgh, Edinburgh, UK
| | - Ahsan R Akram
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK; Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | | | - James W Dear
- Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh,; Centre for Cardiovascular Science, Queen's Medical Research Institute, Bioquarter, University of Edinburgh, Edinburgh, UK
| | - Nik Hirani
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK; Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh
| | - Kevin Dhaliwal
- Centre for Inflammation Research, Queen's Medical Research Institute, BioQuarter, University of Edinburgh, Edinburgh, UK; Royal Infirmary of Edinburgh, BioQuarter, Little France, Edinburgh,.
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Churchill GC, Strupp M, Factor C, Bremova-Ertl T, Factor M, Patterson MC, Platt FM, Galione A. Acetylation turns leucine into a drug by membrane transporter switching. Sci Rep 2021; 11:15812. [PMID: 34349180 PMCID: PMC8338929 DOI: 10.1038/s41598-021-95255-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/23/2021] [Indexed: 02/07/2023] Open
Abstract
Small changes to molecules can have profound effects on their pharmacological activity as exemplified by the addition of the two-carbon acetyl group to make drugs more effective by enhancing their pharmacokinetic or pharmacodynamic properties. N-acetyl-D,L-leucine is approved in France for vertigo and its L-enantiomer is being developed as a drug for rare and common neurological disorders. However, the precise mechanistic details of how acetylation converts leucine into a drug are unknown. Here we show that acetylation of leucine switches its uptake into cells from the L-type amino acid transporter (LAT1) used by leucine to organic anion transporters (OAT1 and OAT3) and the monocarboxylate transporter type 1 (MCT1). Both the kinetics of MCT1 (lower affinity compared to LAT1) and the ubiquitous tissue expression of MCT1 make it well suited for uptake and distribution of N-acetyl-L-leucine. MCT1-mediated uptake of a N-acetyl-L-leucine as a prodrug of leucine bypasses LAT1, the rate-limiting step in activation of leucine-mediated signalling and metabolic process inside cells such as mTOR. Converting an amino acid into an anion through acetylation reveals a way for the rational design of drugs to target anion transporters.
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Affiliation(s)
- Grant C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK.
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Hospital of the Ludwig Maximilians University, Munich, Germany
| | - Cailley Factor
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
| | - Tatiana Bremova-Ertl
- Department of Neurology, University Hospital Inselspital, Bern, BE, Switzerland
- Center for Rare Diseases, University Hospital Inselspital Bern, Bern, BE, Switzerland
| | - Mallory Factor
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
| | - Marc C Patterson
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Frances M Platt
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
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Chen OCW, Colaco A, Davis LC, Kiskin FN, Farhat NY, Speak AO, Smith DA, Morris L, Eden E, Tynan P, Churchill GC, Galione A, Porter FD, Platt FM. Defective platelet function in Niemann-Pick disease type C1. JIMD Rep 2020; 56:46-57. [PMID: 33204596 PMCID: PMC7653256 DOI: 10.1002/jmd2.12148] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/24/2020] [Accepted: 06/26/2020] [Indexed: 11/30/2022] Open
Abstract
Niemann-Pick disease type C (NPC) is a neurodegenerative lysosomal storage disorder caused by mutations in either NPC1 (95% of cases) or NPC2. Reduced late endosome/lysosome calcium (Ca2+) levels and the accumulation of unesterified cholesterol and sphingolipids within the late endocytic system characterize this disease. We previously reported impaired lysosome-related organelle (LRO) function in Npc1 -/- Natural Killer cells; however, the potential contribution of impaired acid compartment Ca2+ flux and LRO function in other cell types has not been determined. Here, we investigated LRO function in NPC1 disease platelets. We found elevated numbers of circulating platelets, impaired platelet aggregation and prolonged bleeding times in a murine model of NPC1 disease. Electron microscopy revealed abnormal ultrastructure in murine platelets, consistent with that seen in a U18666A (pharmacological inhibitor of NPC1) treated megakaryocyte cell line (MEG-01) exhibiting lipid storage and acidic compartment Ca2+ flux defects. Furthermore, platelets from NPC1 patients across different ages were found to cluster at the lower end of the normal range when platelet numbers were measured and had platelet volumes that were clustered at the top of the normal range. Taken together, these findings highlight the role of acid compartment Ca2+ flux in the function of platelet LROs.
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Affiliation(s)
| | | | | | | | - Nicole Y. Farhat
- Division in Translational MedicineEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human ServicesBethesdaMarylandUSA
| | | | | | - Lauren Morris
- Department of PharmacologyUniversity of OxfordOxfordUK
| | - Emily Eden
- Institute of Ophthalmology—Cell BiologyUniversity College LondonLondonUK
| | | | | | | | - Forbes D. Porter
- Division in Translational MedicineEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human ServicesBethesdaMarylandUSA
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Singh N, Serres F, Toker L, Sade Y, Blackburn V, Batra AS, Saiardi A, Agam G, Belmaker RH, Sharp T, Vasudevan SR, Churchill GC. Effects of the putative lithium mimetic ebselen on pilocarpine-induced neural activity. Eur J Pharmacol 2020; 883:173377. [PMID: 32687920 DOI: 10.1016/j.ejphar.2020.173377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 01/21/2023]
Abstract
Lithium, commonly used to treat bipolar disorder, potentiates the ability of the muscarinic agonist pilocarpine to induce seizures in rodents. As this potentiation by lithium is reversed by the administration of myo-inositol, the potentiation may be mediated by inhibition of inositol monophosphatase (IMPase), a known target of lithium. Recently, we demonstrated that ebselen is a 'lithium mimetic' in regard to behaviours in both mice and man. Ebselen inhibits IMPase in vitro and lowers myo-inositol in vivo in the brains of mice and men, making ebselen the only known inhibitor of IMPase, other than lithium, that penetrates the blood-brain barrier. Our objective was to determine the effects of ebselen on sensitization to pilocarpine-induced seizures and neural activity. We administered ebselen at different doses and time intervals to mice, followed by injection of a sub-seizure dose of pilocarpine. We assessed seizure and neural activity by a subjective seizure rating scale, by monitoring tremors, and by induction of the immediate early gene c-fos. In contrast to lithium, ebselen did not potentiate the ability of pilocarpine to induce seizures. Unexpectedly, ebselen inhibited pilocarpine-induced tremor as well as pilocarpine-induced increases in c-fos mRNA levels. Both lithium and ebselen inhibit a common target, IMPase, but only lithium potentiates pilocarpine-induced seizures, consistent with their polypharmacology at diverse molecular targets. We conclude that ebselen does not potentiate pilocarpine-induced seizures and instead, reduces pilocarpine-mediated neural activation. This lack of potentiation of muscarinic sensitization may be one reason for the lack of side-effects observed with ebselen treatment clinically.
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Affiliation(s)
- Nisha Singh
- Department of Pharmacology, University of Oxford, Oxford, UK.
| | - Florence Serres
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Lilah Toker
- Department of Clinical Biochemistry and Pharmacology and Psychiatry Research Unit, Faculty of Health Sciences and Mental Health Centre, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yeala Sade
- Department of Clinical Biochemistry and Pharmacology and Psychiatry Research Unit, Faculty of Health Sciences and Mental Health Centre, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | | | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, UK
| | - Galila Agam
- Department of Clinical Biochemistry and Pharmacology and Psychiatry Research Unit, Faculty of Health Sciences and Mental Health Centre, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Robert H Belmaker
- Department of Clinical Biochemistry and Pharmacology and Psychiatry Research Unit, Faculty of Health Sciences and Mental Health Centre, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Trevor Sharp
- Department of Pharmacology, University of Oxford, Oxford, UK
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Churchill GC, Strupp M, Galione A, Platt FM. Unexpected differences in the pharmacokinetics of N-acetyl-DL-leucine enantiomers after oral dosing and their clinical relevance. PLoS One 2020; 15:e0229585. [PMID: 32108176 PMCID: PMC7046201 DOI: 10.1371/journal.pone.0229585] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 02/11/2020] [Indexed: 12/18/2022] Open
Abstract
The enantiomers of many chiral drugs not only exhibit different pharmacological effects in regard to targets that dictate therapeutic and toxic effects, but are also handled differently in the body due to pharmacokinetic effects. We investigated the pharmacokinetics of the enantiomers of N-acetyl-leucine after administration of the racemate (N-acetyl-DL-leucine) or purified, pharmacologically active L-enantiomer (N-acetyl-L-leucine). The results suggest that during chronic administration of the racemate, the D-enantiomer would accumulate, which could have negative effects. Compounds were administered orally to mice. Plasma and tissue samples were collected at predetermined time points (0.25 to 8 h), quantified with liquid chromatography/mass spectrometry, and pharmacokinetic constants were calculated using a noncompartmental model. When administered as the racemate, both the maximum plasma concentration (Cmax) and the area under the plasma drug concentration over time curve (AUC) were much greater for the D-enantiomer relative to the L-enantiomer. When administered as the L-enantiomer, the dose proportionality was greater than unity compared to the racemate, suggesting saturable processes affecting uptake and/or metabolism. Elimination (ke and T1/2) was similar for both enantiomers. These results are most readily explained by inhibition of uptake at an intestinal carrier of the L-enantiomer by the D-enantiomer, and by first-pass metabolism of the L-, but not D-enantiomer, likely by deacetylation. In brain and muscle, N-acetyl-L-leucine levels were lower than N-acetyl-D-leucine, consistent with rapid conversion into L-leucine and utilization by normal leucine metabolism. In summary, the enantiomers of N-acetyl-leucine exhibit large, unexpected differences in pharmacokinetics due to both unique handling and/or inhibition of uptake and metabolism of the L-enantiomer by the D-enantiomer. Taken together, these results have clinical implications supporting the use of N-acetyl-L-leucine instead of the racemate or N-acetyl-D-leucine, and support the research and development of only N-acetyl-L-leucine.
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Affiliation(s)
- Grant C. Churchill
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Michael Strupp
- Department of Neurology, German Center for Vertigo and Balance Disorders, Ludwig Maximilians University Hospital Munich, Munich, Germany
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Frances M. Platt
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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9
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Singh N, McMahon H, Bilderbeck A, Reed ZE, Tunbridge E, Brett D, Geddes JR, Churchill GC, Goodwin GM. Plasma glutathione suggests oxidative stress is equally present in early- and late-onset bipolar disorder. Bipolar Disord 2019; 21:61-67. [PMID: 29600584 DOI: 10.1111/bdi.12640] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVES We previously demonstrated oxidative stress in bipolar patients and a relationship between the age of illness onset and total glutathione, a principal antioxidant. In this study, we sought to replicate these findings in a new cohort of patients. METHODS We recruited bipolar patients from Warneford Hospital, Oxford, UK, of similar age and grouped them according to age of onset of illness. The early-onset group comprised patients with onset at <23 years, and the late group comprised patients with onset at >30 years. A third group, comprising age-matched healthy volunteers, was also included. Reduced and oxidized glutathione, cysteine, and cystine were determined in plasma, using high-performance liquid chromatography. Mitochondrial DNA copy number, measured in whole blood, was also compared between patients and healthy controls. RESULTS Significant increases in oxidative stress were observed in the patient groups, compared with the control group; however, no differences in glutathione-related oxidative stress measures were detected between the early- and late-onset bipolar patient groups. No differences were observed in the amount of mitochondrial DNA, and there was no correlation with mood state. CONCLUSION Using a more accurate method to quantify oxidative stress than in our previous study, we show that oxidative stress is a consistent feature of bipolar disorder. Although we did not reproduce our finding correlating age of onset of illness to oxidative stress, we have shown, once again, that oxidative stress is a consistent feature of bipolar disorder.
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Affiliation(s)
- Nisha Singh
- Department of Psychiatry and Oxford Health NHS Trust, Warneford Hospital, University of Oxford, Oxford, UK.,Department of Pharmacology, University of Oxford, Oxford, UK.,Centre for Neuroimaging Sciences, IoPPN, King's College, London, UK
| | - Hannah McMahon
- Department of Psychiatry and Oxford Health NHS Trust, Warneford Hospital, University of Oxford, Oxford, UK
| | - Amy Bilderbeck
- Department of Psychiatry and Oxford Health NHS Trust, Warneford Hospital, University of Oxford, Oxford, UK.,P1Vital, Wallingford, UK
| | - Zoe E Reed
- Department of Psychiatry and Oxford Health NHS Trust, Warneford Hospital, University of Oxford, Oxford, UK.,MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Elizabeth Tunbridge
- Department of Psychiatry and Oxford Health NHS Trust, Warneford Hospital, University of Oxford, Oxford, UK
| | - Daniel Brett
- Department of Psychiatry and Oxford Health NHS Trust, Warneford Hospital, University of Oxford, Oxford, UK
| | - John R Geddes
- Department of Psychiatry and Oxford Health NHS Trust, Warneford Hospital, University of Oxford, Oxford, UK
| | | | - Guy M Goodwin
- Department of Psychiatry and Oxford Health NHS Trust, Warneford Hospital, University of Oxford, Oxford, UK
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10
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Barkus C, Ferland JMN, Adams WK, Churchill GC, Cowen PJ, Bannerman DM, Rogers RD, Winstanley CA, Sharp T. The putative lithium-mimetic ebselen reduces impulsivity in rodent models. J Psychopharmacol 2018; 32:1018-1026. [PMID: 29986609 DOI: 10.1177/0269881118784876] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Deficits in impulse control feature in many psychiatric conditions including bipolar disorder, suicidality and addictions. Lithium lowers impulsivity in clinical populations and decreases pathological gambling in experimental medicine studies, but suffers from adverse effects, poor compliance and a low therapeutic index. AIMS Recently we identified that the neuroprotective agent ebselen, which is reportedly safe in humans, inhibited inositol monophosphatase (IMPase), a candidate lithium mechanism. Ebselen also reduced 5-HT receptor (5-HT2A) function which predicts impulsivity lowering properties. Here we investigated the effect of ebselen in rat models of impulsive behaviour. METHODS Ebselen was tested in two models of impulsivity with human analogues: the five-choice serial reaction time task (5-CSRTT) and rodent gambling task (rGT). The main outcome measures were premature responses (5-CSRTT and rGT) and choice behaviour (rGT), which model motor impulsivity and choice impulsivity, respectively. RESULTS At doses that decreased 5-HT2A receptor function (DOI-induced wet dog shakes), ebselen decreased premature responding in the 5-CSRTT both in the absence and presence of cocaine. The 5-HT2A receptor antagonist MDL 100,907 also reduced premature responding in the 5-CSRTT although not in the presence of cocaine. In the rGT ebselen showed a tendency to reduce premature responding but had no effect on choice behaviour. CONCLUSIONS These findings suggest that ebselen preferentially reduces motor impulsivity over choice impulsivity, and that inhibition of 5-HT2A receptor function is a contributing mechanism. Collectively, these data support the repurposing of ebselen as an anti-impulsive treatment and fast-tracking to clinical trials in patient groups characterised by poor impulse control.
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Affiliation(s)
- Chris Barkus
- 1 Department of Pharmacology, University of Oxford, UK
- 2 Department of Psychology, University of British Columbia, Vancouver, Canada
| | | | - Wendy K Adams
- 2 Department of Psychology, University of British Columbia, Vancouver, Canada
| | | | | | | | | | | | - Trevor Sharp
- 1 Department of Pharmacology, University of Oxford, UK
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11
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Antoniadou I, Kouskou M, Arsiwala T, Singh N, Vasudevan SR, Fowler T, Cadirci E, Churchill GC, Sharp T. Ebselen has lithium-like effects on central 5-HT 2A receptor function. Br J Pharmacol 2018; 175:2599-2610. [PMID: 29488218 DOI: 10.1111/bph.14179] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/23/2018] [Accepted: 01/30/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Lithium's antidepressant action may be mediated by inhibition of inositol monophosphatase (IMPase), a key enzyme in Gq -protein coupled receptor signalling. Recently, the antioxidant agent ebselen was identified as an IMPase inhibitor. Here, we investigated both ebselen and lithium in models of the 5-HT2A receptor, a Gq -protein coupled receptor involved in lithium's actions. EXPERIMENTAL APPROACH 5-HT2A receptor function was assessed in mice by measuring the behavioural (head-twitches, ear scratches) and molecular (cortical immediate early gene [IEG] mRNA; Arc, c-fos, Egr2) responses to 5-HT2A receptor agonists. Ebselen and lithium were administered either acutely or repeatedly prior to assessment of 5-HT2A receptor function. Because lithium and 5-HT2A receptor antagonists augment the action of selective serotonin reuptake inhibitors (SSRIs), ebselen was tested for this activity by co-administration with the SSRI citalopram in microdialysis (extracellular 5-HT) experiments. KEY RESULTS Acute and repeated administration of ebselen inhibited behavioural and IEG responses to the 5-HT2A receptor agonist DOI. Repeated lithium also inhibited DOI-evoked behavioural and IEG responses. In comparison, a selective IMPase inhibitor (L-690330) attenuated the behavioural response to DOI whereas glycogen synthase kinase inhibitor (AR-A014418) did not. Finally, ebselen enhanced the increase in extracellular 5-HT induced by citalopram, and also increased regional brain 5-HT synthesis. CONCLUSIONS AND IMPLICATIONS Our data demonstrated lithium-mimetic effects of ebselen in different experimental models of 5-HT2A receptor function, probably mediated by IMPase inhibition. This evidence of lithium-like neuropharmacological effects of ebselen adds further support for the clinical testing of ebselen in mood disorders, including as an antidepressant augmenting agent.
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Affiliation(s)
- I Antoniadou
- Department of Pharmacology, University of Oxford, Oxford, UK.,Department of Pharmacy, European University of Cyprus, Nicosia, Cyprus
| | - M Kouskou
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - T Arsiwala
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - N Singh
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - S R Vasudevan
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - T Fowler
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - E Cadirci
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - G C Churchill
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - T Sharp
- Department of Pharmacology, University of Oxford, Oxford, UK
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12
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Fernández B, Fdez E, Gómez-Suaga P, Gil F, Molina-Villalba I, Ferrer I, Patel S, Churchill GC, Hilfiker S. Iron overload causes endolysosomal deficits modulated by NAADP-regulated 2-pore channels and RAB7A. Autophagy 2016; 12:1487-506. [PMID: 27383256 PMCID: PMC5082776 DOI: 10.1080/15548627.2016.1190072] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 05/05/2016] [Accepted: 05/11/2016] [Indexed: 12/19/2022] Open
Abstract
Various neurodegenerative disorders are associated with increased brain iron content. Iron is known to cause oxidative stress, which concomitantly promotes cell death. Whereas endolysosomes are known to serve as intracellular iron storage organelles, the consequences of increased iron on endolysosomal functioning, and effects on cell viability upon modulation of endolysosomal iron release remain largely unknown. Here, we show that increasing intracellular iron causes endolysosomal alterations associated with impaired autophagic clearance of intracellular protein aggregates, increased cytosolic oxidative stress and increased cell death. These effects are subject to regulation by NAADP, a potent second messenger reported to target endolysosomal TPCNs (2-pore channels). Consistent with endolysosomal iron storage, cytosolic iron levels are modulated by NAADP, and increased cytosolic iron is detected when overexpressing active, but not inactive TPCNs, indicating that these channels can modulate endolysosomal iron release. Cell death triggered by altered intralysosomal iron handling is abrogated in the presence of an NAADP antagonist or when inhibiting RAB7A activity. Taken together, our results suggest that increased endolysosomal iron causes cell death associated with increased cytosolic oxidative stress as well as autophagic impairments, and these effects are subject to modulation by endolysosomal ion channel activity in a RAB7A-dependent manner. These data highlight alternative therapeutic strategies for neurodegenerative disorders associated with increased intracellular iron load.
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Affiliation(s)
- Belén Fernández
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Elena Fdez
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Patricia Gómez-Suaga
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Fernando Gil
- Department of Legal Medicine and Toxicology, School of Medicine, University of Granada, Granada, Spain
| | - Isabel Molina-Villalba
- Department of Legal Medicine and Toxicology, School of Medicine, University of Granada, Granada, Spain
| | - Isidro Ferrer
- Institute of Neuropathology, IDIBELL-University Hospital Bellvitge, University of Barcelona, Llobregat, Spain
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK
| | | | - Sabine Hilfiker
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
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13
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Singh N, Sharpley AL, Emir UE, Masaki C, Herzallah MM, Gluck MA, Sharp T, Harmer CJ, Vasudevan SR, Cowen PJ, Churchill GC. Effect of the Putative Lithium Mimetic Ebselen on Brain Myo-Inositol, Sleep, and Emotional Processing in Humans. Neuropsychopharmacology 2016; 41:1768-78. [PMID: 26593266 PMCID: PMC4770517 DOI: 10.1038/npp.2015.343] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/25/2015] [Accepted: 11/11/2015] [Indexed: 01/09/2023]
Abstract
Lithium remains the gold standard in treating bipolar disorder but has unwanted toxicity and side effects. We previously reported that ebselen inhibits inositol monophosphatase (IMPase) and exhibits lithium-like effects in animal models through lowering of inositol. Ebselen has been tested in clinical trials for other disorders, enabling us to determine for the first time the effect of a blood-brain barrier-penetrant IMPase inhibitor on human central nervous system (CNS) function. We now report that in a double-blind, placebo-controlled trial with healthy participants, acute oral ebselen reduced brain myo-inositol in the anterior cingulate cortex, consistent with CNS target engagement. Ebselen decreased slow-wave sleep and affected emotional processing by increasing recognition of some emotions, decreasing latency time in the acoustic startle paradigm, and decreasing the reinforcement of rewarding stimuli. In summary, ebselen affects the phosphoinositide cycle and has CNS effects on surrogate markers that may be relevant to the treatment of bipolar disorder that can be tested in future clinical trials.
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Affiliation(s)
- Nisha Singh
- Department of Pharmacology, University of Oxford, Oxford, UK,Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Ann L Sharpley
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Uzay E Emir
- The Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Charles Masaki
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Mohammad M Herzallah
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, USA,Palestinian Neuroscience Initiative, Faculty of Medicine, Al-Quds University, Abu Dis, Jerusalem, Palestine
| | - Mark A Gluck
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Trevor Sharp
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Catherine J Harmer
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | | | - Philip J Cowen
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford, UK,Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK, Tel: +44 (0)1865 271 635, Fax: +44 (0)1865 271 853, E-mail:
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14
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Masaki C, Sharpley AL, Godlewska BR, Berrington A, Hashimoto T, Singh N, Vasudevan SR, Emir UE, Churchill GC, Cowen PJ. Effects of the potential lithium-mimetic, ebselen, on brain neurochemistry: a magnetic resonance spectroscopy study at 7 tesla. Psychopharmacology (Berl) 2016; 233:1097-104. [PMID: 26758281 PMCID: PMC4759215 DOI: 10.1007/s00213-015-4189-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 12/13/2015] [Indexed: 11/27/2022]
Abstract
RATIONALE Lithium is an effective treatment for bipolar disorder, but safety issues complicate its clinical use. The antioxidant drug, ebselen, may be a possible lithium-mimetic based on its ability to inhibit inositol monophosphatase (IMPase), an action which it shares with lithium. OBJECTIVES Our primary aim was to determine whether ebselen lowered levels of inositol in the human brain. We also assessed the effect of ebselen on other brain neurometabolites, including glutathione, glutamate, glutamine, and glutamate + glutamine (Glx) METHODS Twenty healthy volunteers were tested on two occasions receiving either ebselen (3600 mg over 24 h) or identical placebo in a double-blind, random-order, crossover design. Two hours after the final dose of ebselen/placebo, participants underwent proton magnetic resonance spectroscopy ((1)H MRS) at 7 tesla (T) with voxels placed in the anterior cingulate and occipital cortex. Neurometabolite levels were calculated using an unsuppressed water signal as a reference and corrected for individual cerebrospinal fluid content in the voxel. RESULTS Ebselen produced no effect on neurometabolite levels in the occipital cortex. In the anterior cingulate cortex, ebselen lowered concentrations of inositol (p = 0.028, Cohen's d = 0.60) as well as those of glutathione (p = 0.033, d = 0.58), glutamine (p = 0.024, d = 0.62), glutamate (p = 0.01, d = 0.73), and Glx (p = 0.001, d = 1.0). CONCLUSIONS The study suggests that ebselen produces a functional inhibition of IMPase in the human brain. The effect of ebselen to lower glutamate is consistent with its reported ability to inhibit the enzyme, glutaminase. Ebselen may have potential as a repurposed treatment for bipolar disorder.
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Affiliation(s)
- Charles Masaki
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, OX3 7JX, UK
| | - Ann L Sharpley
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, OX3 7JX, UK
| | - Beata R Godlewska
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, OX3 7JX, UK
| | - Adam Berrington
- The Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Tasuku Hashimoto
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, OX3 7JX, UK
| | - Nisha Singh
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
- Current Address: Centre for Neuroimaging Studies, PO 089, De Crespigny Park, London, SE5 8AF, UK
| | - Sridhar R Vasudevan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Uzay E Emir
- The Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Philip J Cowen
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, OX3 7JX, UK.
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15
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Masaki C, Sharpley AL, Cooper CM, Godlewska BR, Singh N, Vasudevan SR, Harmer CJ, Churchill GC, Sharp T, Rogers RD, Cowen PJ. Effects of the potential lithium-mimetic, ebselen, on impulsivity and emotional processing. Psychopharmacology (Berl) 2016; 233:2655-61. [PMID: 27256357 PMCID: PMC4917572 DOI: 10.1007/s00213-016-4319-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 02/22/2016] [Indexed: 11/30/2022]
Abstract
RATIONALE Lithium remains the most effective treatment for bipolar disorder and also has important effects to lower suicidal behaviour, a property that may be linked to its ability to diminish impulsive, aggressive behaviour. The antioxidant drug, ebselen, has been proposed as a possible lithium-mimetic based on its ability in animals to inhibit inositol monophosphatase (IMPase), an action which it shares with lithium. OBJECTIVES The aim of the study was to determine whether treatment with ebselen altered emotional processing and diminished measures of risk-taking behaviour. METHODS We studied 20 healthy participants who were tested on two occasions receiving either ebselen (3600 mg over 24 h) or identical placebo in a double-blind, randomized, cross-over design. Three hours after the final dose of ebselen/placebo, participants completed the Cambridge Gambling Task (CGT) and a task that required the detection of emotional facial expressions (facial emotion recognition task (FERT)). RESULTS On the CGT, relative to placebo, ebselen reduced delay aversion while on the FERT, it increased the recognition of positive vs negative facial expressions. CONCLUSIONS The study suggests that at the dosage used, ebselen can decrease impulsivity and produce a positive bias in emotional processing. These findings have implications for the possible use of ebselen in the disorders characterized by impulsive behaviour and dysphoric mood.
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Affiliation(s)
- Charles Masaki
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK
| | - Ann L Sharpley
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK
| | - Charlotte M Cooper
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK
| | - Beata R Godlewska
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK
| | - Nisha Singh
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
- Centre for Neuroimaging Studies, PO 089, DeCrespigny Park, London, SE5 8AF, UK
| | - Sridhar R Vasudevan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Catherine J Harmer
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Trevor Sharp
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Robert D Rogers
- School of Psychology, Bangor University, Penrallt Road, Gwynedd, LL57 2AS, UK
| | - Philip J Cowen
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK.
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16
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Kilpatrick BS, Magalhaes J, Beavan MS, McNeill A, Gegg ME, Cleeter MWJ, Bloor-Young D, Churchill GC, Duchen MR, Schapira AH, Patel S. Endoplasmic reticulum and lysosomal Ca²⁺ stores are remodelled in GBA1-linked Parkinson disease patient fibroblasts. Cell Calcium 2015; 59:12-20. [PMID: 26691915 PMCID: PMC4751977 DOI: 10.1016/j.ceca.2015.11.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/06/2015] [Accepted: 11/25/2015] [Indexed: 11/19/2022]
Abstract
Mutations in β-glucocerebrosidase (encoded by GBA1) cause Gaucher disease (GD), a lysosomal storage disorder, and increase the risk of developing Parkinson disease (PD). The pathogenetic relationship between the two disorders is unclear. Here, we characterised Ca(2+) release in fibroblasts from type I GD and PD patients together with age-matched, asymptomatic carriers, all with the common N370S mutation in β-glucocerebrosidase. We show that endoplasmic reticulum (ER) Ca(2+) release was potentiated in GD and PD patient fibroblasts but not in cells from asymptomatic carriers. ER Ca(2+) signalling was also potentiated in fibroblasts from aged healthy subjects relative to younger individuals but not further increased in aged PD patient cells. Chemical or molecular inhibition of β-glucocerebrosidase in fibroblasts and a neuronal cell line did not affect ER Ca(2+) signalling suggesting defects are independent of enzymatic activity loss. Conversely, lysosomal Ca(2+) store content was reduced in PD fibroblasts and associated with age-dependent alterations in lysosomal morphology. Accelerated remodelling of Ca(2+) stores by pathogenic GBA1 mutations may therefore feature in PD.
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Affiliation(s)
- Bethan S Kilpatrick
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Joana Magalhaes
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
| | - Michelle S Beavan
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
| | - Alisdair McNeill
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
| | - Matthew E Gegg
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
| | - Michael W J Cleeter
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
| | | | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Anthony H Schapira
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
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17
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Hui L, Geiger NH, Bloor-Young D, Churchill GC, Geiger JD, Chen X. Release of calcium from endolysosomes increases calcium influx through N-type calcium channels: Evidence for acidic store-operated calcium entry in neurons. Cell Calcium 2015; 58:617-27. [PMID: 26475051 DOI: 10.1016/j.ceca.2015.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/02/2015] [Accepted: 10/04/2015] [Indexed: 01/22/2023]
Abstract
Neurons possess an elaborate system of endolysosomes. Recently, endolysosomes were found to have readily releasable stores of intracellular calcium; however, relatively little is known about how such 'acidic calcium stores' affect calcium signaling in neurons. Here we demonstrated in primary cultured neurons that calcium released from acidic calcium stores triggered calcium influx across the plasma membrane, a phenomenon we have termed "acidic store-operated calcium entry (aSOCE)". aSOCE was functionally distinct from store-operated calcium release and calcium entry involving endoplasmic reticulum. aSOCE appeared to be governed by N-type calcium channels (NTCCs) because aSOCE was attenuated significantly by selectively blocking NTCCs or by siRNA knockdown of NTCCs. Furthermore, we demonstrated that NTCCs co-immunoprecipitated with the lysosome associated membrane protein 1 (LAMP1), and that aSOCE is accompanied by increased cell-surface expression levels of NTCC and LAMP1 proteins. Moreover, we demonstrated that siRNA knockdown of LAMP1 or Rab27a, both of which are key proteins involved in lysosome exocytosis, attenuated significantly aSOCE. Taken together our data suggest that aSOCE occurs in neurons, that aSOCE plays an important role in regulating the levels and actions of intraneuronal calcium, and that aSOCE is regulated at least in part by exocytotic insertion of N-type calcium channels into plasma membranes through LAMP1-dependent lysosome exocytosis.
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Affiliation(s)
- Liang Hui
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Nicholas H Geiger
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Duncan Bloor-Young
- Department of Pharmacology, University of Oxford, Mansfield Rd., Oxford OX1 3QT, UK
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Rd., Oxford OX1 3QT, UK
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
| | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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18
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Capel RA, Bolton EL, Lin WK, Aston D, Wang Y, Liu W, Wang X, Burton RAB, Bloor-Young D, Shade KT, Ruas M, Parrington J, Churchill GC, Lei M, Galione A, Terrar DA. Two-pore Channels (TPC2s) and Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) at Lysosomal-Sarcoplasmic Reticular Junctions Contribute to Acute and Chronic β-Adrenoceptor Signaling in the Heart. J Biol Chem 2015; 290:30087-98. [PMID: 26438825 PMCID: PMC4705968 DOI: 10.1074/jbc.m115.684076] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 12/12/2022] Open
Abstract
Ca2+-permeable type 2 two-pore channels (TPC2) are lysosomal proteins required for nicotinic acid adenine dinucleotide phosphate (NAADP)-evoked Ca2+ release in many diverse cell types. Here, we investigate the importance of TPC2 proteins for the physiology and pathophysiology of the heart. NAADP-AM failed to enhance Ca2+ responses in cardiac myocytes from Tpcn2−/− mice, unlike myocytes from wild-type (WT) mice. Ca2+/calmodulin-dependent protein kinase II inhibitors suppressed actions of NAADP in myocytes. Ca2+ transients and contractions accompanying action potentials were increased by isoproterenol in myocytes from WT mice, but these effects of β-adrenoreceptor stimulation were reduced in myocytes from Tpcn2−/− mice. Increases in amplitude of L-type Ca2+ currents evoked by isoproterenol remained unchanged in myocytes from Tpcn2−/− mice showing no loss of β-adrenoceptors or coupling mechanisms. Whole hearts from Tpcn2−/− mice also showed reduced inotropic effects of isoproterenol and a reduced tendency for arrhythmias following acute β-adrenoreceptor stimulation. Hearts from Tpcn2−/− mice chronically exposed to isoproterenol showed less cardiac hypertrophy and increased threshold for arrhythmogenesis compared with WT controls. Electron microscopy showed that lysosomes form close contacts with the sarcoplasmic reticulum (separation ∼25 nm). We propose that Ca2+-signaling nanodomains between lysosomes and sarcoplasmic reticulum dependent on NAADP and TPC2 comprise an important element in β-adrenoreceptor signal transduction in cardiac myocytes. In summary, our observations define a role for NAADP and TPC2 at lysosomal/sarcoplasmic reticulum junctions as unexpected but major contributors in the acute actions of β-adrenergic signaling in the heart and also in stress pathways linking chronic stimulation of β-adrenoceptors to hypertrophy and associated arrhythmias.
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Affiliation(s)
- Rebecca A Capel
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Emma L Bolton
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Wee K Lin
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Daniel Aston
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Yanwen Wang
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Wei Liu
- the Faculty of Life Science, University of Manchester, Manchester M13 9NT, and
| | - Xin Wang
- the Faculty of Life Science, University of Manchester, Manchester M13 9NT, and
| | - Rebecca-Ann B Burton
- the Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Sherrington Road, Oxford OX1 3PT, United Kingdom
| | - Duncan Bloor-Young
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Kai-Ting Shade
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Margarida Ruas
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - John Parrington
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Grant C Churchill
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Ming Lei
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Antony Galione
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT
| | - Derek A Terrar
- From the Department of Pharmacology, BHF Centre of Research Excellence, University of Oxford, Mansfield Road, Oxford OX1 3QT,
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19
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Arredouani A, Ruas M, Collins SC, Parkesh R, Clough F, Pillinger T, Coltart G, Rietdorf K, Royle A, Johnson P, Braun M, Zhang Q, Sones W, Shimomura K, Morgan AJ, Lewis AM, Chuang KT, Tunn R, Gadea J, Teboul L, Heister PM, Tynan PW, Bellomo EA, Rutter GA, Rorsman P, Churchill GC, Parrington J, Galione A. Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) and Endolysosomal Two-pore Channels Modulate Membrane Excitability and Stimulus-Secretion Coupling in Mouse Pancreatic β Cells. J Biol Chem 2015; 290:21376-92. [PMID: 26152717 PMCID: PMC4571866 DOI: 10.1074/jbc.m115.671248] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Indexed: 12/02/2022] Open
Abstract
Pancreatic β cells are electrically excitable and respond to elevated glucose concentrations with bursts of Ca2+ action potentials due to the activation of voltage-dependent Ca2+ channels (VDCCs), which leads to the exocytosis of insulin granules. We have examined the possible role of nicotinic acid adenine dinucleotide phosphate (NAADP)-mediated Ca2+ release from intracellular stores during stimulus-secretion coupling in primary mouse pancreatic β cells. NAADP-regulated Ca2+ release channels, likely two-pore channels (TPCs), have recently been shown to be a major mechanism for mobilizing Ca2+ from the endolysosomal system, resulting in localized Ca2+ signals. We show here that NAADP-mediated Ca2+ release from endolysosomal Ca2+ stores activates inward membrane currents and depolarizes the β cell to the threshold for VDCC activation and thereby contributes to glucose-evoked depolarization of the membrane potential during stimulus-response coupling. Selective pharmacological inhibition of NAADP-evoked Ca2+ release or genetic ablation of endolysosomal TPC1 or TPC2 channels attenuates glucose- and sulfonylurea-induced membrane currents, depolarization, cytoplasmic Ca2+ signals, and insulin secretion. Our findings implicate NAADP-evoked Ca2+ release from acidic Ca2+ storage organelles in stimulus-secretion coupling in β cells.
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Affiliation(s)
- Abdelilah Arredouani
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom,
| | - Margarida Ruas
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Stephan C Collins
- the Centre des Sciences du Gout et de l'Alimentation, Equipe 5, 9E Boulevard Jeanne d'Arc 21000 Dijon, France
| | - Raman Parkesh
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Frederick Clough
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Toby Pillinger
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - George Coltart
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Katja Rietdorf
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Andrew Royle
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Paul Johnson
- the Nuffield Department of Surgery, John Radcliffe Hospital, Headley Way, Headington, Oxford OX3 9DU, United Kingdom
| | - Matthias Braun
- the The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - Quan Zhang
- the The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - William Sones
- the The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - Kenju Shimomura
- the Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy, and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, United Kingdom
| | - Anthony J Morgan
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Alexander M Lewis
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Kai-Ting Chuang
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Ruth Tunn
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Joaquin Gadea
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Lydia Teboul
- The Mary Lyon Centre, Medical Research Council Harwell, Oxfordshire OX11 0RD, United Kingdom
| | - Paula M Heister
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Patricia W Tynan
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Elisa A Bellomo
- the Centre des Sciences du Gout et de l'Alimentation, Equipe 5, 9E Boulevard Jeanne d'Arc 21000 Dijon, France
| | - Guy A Rutter
- the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Medicine, Imperial College London, Hammersmith Hospital, du Cane Road, London W12 0NN, United Kingdom, and
| | - Patrik Rorsman
- the The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - Grant C Churchill
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - John Parrington
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom,
| | - Antony Galione
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom,
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20
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Vasudevan SR, Singh N, Churchill GC. Scaffold hopping with virtual screening from IP3 to a drug-like partial agonist of the inositol trisphosphate receptor. Chembiochem 2014; 15:2774-82. [PMID: 25399672 DOI: 10.1002/cbic.201402440] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Indexed: 11/06/2022]
Abstract
Inositol 1,4,5-trisphosphate (IP3 ) is a universal signalling molecule that releases calcium from stores within cells by activating the IP3 receptor. Although chemical tools that modulate the IP3 receptor exist, none is ideal due to trade offs between potency, selectivity and cell permeability, and their chemical properties make them challenging starting points for optimisation. Therefore, to find new leads, we used virtual screening to scaffold hop from IP3 by using the program ROCS to perform a 3D ligand-based screen of the ZINC database of purchasable compounds. We then used the program FRED to dock the top-ranking hits into the IP3 binding pocket of the receptor. We tested the 12 highest-scoring hits in a calcium-release bioassay and identified SI-9 as a partial agonist. SI-9 competed with [(3) H]IP3 binding, and reduced histamine-induced calcium signalling in HeLa cells. SI-9 has a novel 2D scaffold that represents a tractable lead for designing improved IP3 receptor modulators.
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Affiliation(s)
- Sridhar R Vasudevan
- Department of Pharmacology, University of Oxford, Mansfield Road, OX1 3QT (UK).
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21
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Galione A, Chuang KT, Funnell TM, Davis LC, Morgan AJ, Ruas M, Parrington J, Churchill GC. Synthesis of caged NAADP. Cold Spring Harb Protoc 2014; 2014:pdb.prot076943. [PMID: 25275103 DOI: 10.1101/pdb.prot076943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Caged derivatives of Ca²⁺-mobilizing messengers, such as nicotinic acid adenine dinucleotide phosphate (NAADP), are particularly useful for establishing the effects of these messengers on Ca²⁺ signaling. Caged NAADP is no longer commercially available but can be synthesized in house, as described here. In brief, a stable precursor of the caging reagent is made and converted to an unstable reactive reagent immediately before addition to the compound to be caged.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Kai-Ting Chuang
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Tim M Funnell
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Margarida Ruas
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - John Parrington
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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22
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Galione A, Chuang KT, Funnell TM, Davis LC, Morgan AJ, Ruas M, Parrington J, Churchill GC. Measurement of luminal pH of acidic stores as a readout for NAADP action. Cold Spring Harb Protoc 2014; 2014:pdb.prot076935. [PMID: 25275102 DOI: 10.1101/pdb.prot076935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In addition to mobilizing Ca²⁺, NAADP plays a role in modulating the luminal pH (pHL) of acidic stores of the endolysosomal system. The effects of NAADP on pHL have been most extensively studied in the sea urchin egg, both in the intact egg and in egg homogenates. Related observations have also been made in mammalian systems (e.g., guinea pig atrial myocytes and pancreatic acinar cells). Although the connection between Ca²⁺ mobilization and increase in pHL is not understood, pHL can be a useful parameter to measure when studying NAADP-mediated signaling. This protocol describes the fluorescent measurement of pHL of acidic stores. It relies on the use of acridine orange (AO), a standard dye for pHL. AO selectively accumulates to high concentrations in the lumen of organelles as a function of acidity; at these high concentrations it self-quenches. When pHL increases, some AO is lost from the vesicle. As a result, the lower luminal AO concentration relieves the quenching and fluorescence increases in the lumen.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Kai-Ting Chuang
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Tim M Funnell
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Margarida Ruas
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - John Parrington
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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23
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Galione A, Chuang KT, Funnell TM, Davis LC, Morgan AJ, Ruas M, Parrington J, Churchill GC. Synthesis of NAADP-AM as a membrane-permeant NAADP analog. Cold Spring Harb Protoc 2014; 2014:pdb.prot076927. [PMID: 25275101 DOI: 10.1101/pdb.prot076927] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP), like the other major messengers for Ca²⁺ mobilization, is passively membrane-impermeant. Instead, a cell-permeant acetoxymethyl ester derivative of NAADP (NAADP-AM) can be synthesized as described here and used to study NAADP-mediated Ca²⁺ release.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Kai-Ting Chuang
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Tim M Funnell
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Margarida Ruas
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - John Parrington
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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24
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Galione A, Chuang KT, Funnell TM, Davis LC, Morgan AJ, Ruas M, Parrington J, Churchill GC. Synthesis of [³²P]NAADP for the radioreceptor binding assay. Cold Spring Harb Protoc 2014; 2014:993-5. [PMID: 25183813 DOI: 10.1101/pdb.prot076919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a major messenger for Ca(2+) mobilization in cells. NAADP-binding proteins are highly selective and have a strong affinity for NAADP. This is the basis of the radioreceptor binding assay, which is used to measure NAADP levels in cells and tissues and to identify cellular stimuli that use NAADP as an intracellular messenger. In the radioreceptor binding assay, radiolabeled NAADP ([(32)P]NAADP) competes with endogenous NAADP present in samples for binding to their receptors. Here, we describe the synthesis of [(32)P]NAADP for use in the radioreceptor binding assay.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Kai-Ting Chuang
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Tim M Funnell
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Margarida Ruas
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - John Parrington
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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25
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Galione A, Chuang KT, Funnell TM, Davis LC, Morgan AJ, Ruas M, Parrington J, Churchill GC. Preparation and use of sea urchin egg homogenates for studying NAADP-mediated Ca²⁺ release. Cold Spring Harb Protoc 2014; 2014:988-92. [PMID: 25183812 DOI: 10.1101/pdb.prot076901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
NAADP and other Ca(2+)-mobilizing messengers are membrane impermeant and thus must be added directly to cell-free or broken-cell preparations to effect Ca(2+) release. The sea urchin egg homogenate, where the biological activity of NAADP was first reported, remains the gold standard cell-free system for studying NAADP-mediated Ca(2+) release. Here we describe how to prepare sea urchin egg homogenate and use it to measure NAADP-mediated Ca(2+) release.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Kai-Ting Chuang
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Tim M Funnell
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Margarida Ruas
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - John Parrington
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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26
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Rosa AR, Singh N, Whitaker E, de Brito M, Lewis AM, Vieta E, Churchill GC, Geddes JR, Goodwin GM. Altered plasma glutathione levels in bipolar disorder indicates higher oxidative stress; a possible risk factor for illness onset despite normal brain-derived neurotrophic factor (BDNF) levels. Psychol Med 2014; 44:2409-2418. [PMID: 24467931 DOI: 10.1017/s0033291714000014] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Oxidative stress and neurotrophic factors have been implicated in the pathophysiology of bipolar disorder. Our objective was to determine whether plasma glutathione or brain-derived neurotrophic factor (BDNF) levels were abnormal in bipolar disorder and therefore useful as possible biomarkers. METHOD Blood samples were collected from subsyndromal, medicated bipolar I patients (n = 50), recruited from OXTEXT, University of Oxford, and from 50 matched healthy controls. Total and oxidized glutathione levels were measured using an enzymatic recycling method and used to calculate reduced, percentage oxidized, ratio of reduced:oxidized and redox state. BDNF was measured using an enzyme-linked immunoassay. Self-monitored mood scores for the bipolar group were available (Quick Inventory of Depressive Symptomatology and the Altman Self-Rating Mania Scale) over an 8-week period. RESULTS Compared with controls, bipolar patients had significantly lower levels of total glutathione and it was more oxidized. BDNF levels were not different. Age of illness onset but not current mood state correlated with total glutathione levels and its oxidation status, so that lower levels of total and reduced glutathione were associated with later onset of disease, not length of illness. CONCLUSIONS Plasma glutathione levels and redox state detect oxidative stress even in subsyndromal patients with normal BDNF. It may relate to the onset and development of bipolar disorder. Plasma glutathione appears to be a suitable biomarker for detecting underlying oxidative stress and for evaluating the efficacy of antioxidant intervention studies.
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Affiliation(s)
- A R Rosa
- Bipolar Disorders Program, Institute of Neurosciences, Hospital Clinic,University of Barcelona,IDIBAPS, CIBERSAM,Spain
| | - N Singh
- Department of Pharmacology,University of Oxford,Oxford,UK
| | - E Whitaker
- Department of Pharmacology,University of Oxford,Oxford,UK
| | - M de Brito
- Department of Pharmacology,University of Oxford,Oxford,UK
| | - A M Lewis
- Department of Pharmacology,University of Oxford,Oxford,UK
| | - E Vieta
- Bipolar Disorders Program, Institute of Neurosciences, Hospital Clinic,University of Barcelona,IDIBAPS, CIBERSAM,Spain
| | - G C Churchill
- Department of Pharmacology,University of Oxford,Oxford,UK
| | - J R Geddes
- Department of Psychiatry, Warneford Hospital,University of Oxford,Oxford,UK
| | - G M Goodwin
- Department of Psychiatry, Warneford Hospital,University of Oxford,Oxford,UK
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27
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Taylor L, Vasudevan SR, Jones CI, Gibbins JM, Churchill GC, Campbell RD, Coxon CH. Discovery of novel GPVI receptor antagonists by structure-based repurposing. PLoS One 2014; 9:e101209. [PMID: 24971515 PMCID: PMC4074120 DOI: 10.1371/journal.pone.0101209] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 06/04/2014] [Indexed: 01/30/2023] Open
Abstract
Inappropriate platelet aggregation creates a cardiovascular risk that is largely managed with thienopyridines and aspirin. Although effective, these drugs carry risks of increased bleeding and drug ‘resistance’, underpinning a drive for new antiplatelet agents. To discover such drugs, one strategy is to identify a suitable druggable target and then find small molecules that modulate it. A good and unexploited target is the platelet collagen receptor, GPVI, which promotes thrombus formation. To identify inhibitors of GPVI that are safe and bioavailable, we docked a FDA-approved drug library into the GPVI collagen-binding site in silico. We now report that losartan and cinanserin inhibit GPVI-mediated platelet activation in a selective, competitive and dose-dependent manner. This mechanism of action likely underpins the cardioprotective effects of losartan that could not be ascribed to its antihypertensive effects. We have, therefore, identified small molecule inhibitors of GPVI-mediated platelet activation, and also demonstrated the utility of structure-based repurposing.
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Affiliation(s)
- Lewis Taylor
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, United Kingdom
| | - Sridhar R. Vasudevan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, United Kingdom
| | - Chris I. Jones
- Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Hopkins Building, Reading, United Kingdom
| | - Jonathan M. Gibbins
- Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Hopkins Building, Reading, United Kingdom
| | - Grant C. Churchill
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, United Kingdom
| | - R. Duncan Campbell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, United Kingdom
| | - Carmen H. Coxon
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford, United Kingdom
- * E-mail:
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Bayliss RA, Lin W, Bolton E, Bloor-Young D, Churchill GC, Galione A, Terrar DA. CaMKII-Mediated Amplification is Essential to NAADP Signalling in Cardiac Myocytes. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.1420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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29
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Sánchez-Tusie AA, Vasudevan SR, Churchill GC, Nishigaki T, Treviño CL. Characterization of NAADP-mediated calcium signaling in human spermatozoa. Biochem Biophys Res Commun 2013; 443:531-6. [PMID: 24326068 DOI: 10.1016/j.bbrc.2013.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 12/02/2013] [Indexed: 11/17/2022]
Abstract
Ca(2+) signaling in spermatozoa plays a crucial role during processes such as capacitation and release of the acrosome, but the underlying molecular mechanisms still remain unclear. Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent Ca(2+)-releasing second messenger in a variety of cellular processes. The presence of a NAADP synthesizing enzyme in sea urchin sperm has been previously reported, suggesting a possible role of NAADP in sperm Ca(2+) signaling. In this work we used in vitro enzyme assays to show the presence of a novel NAADP synthesizing enzyme in human sperm, and to characterize its sensitivity to Ca(2+) and pH. Ca(2+) fluorescence imaging studies demonstrated that the permeable form of NAADP (NAADP-AM) induces intracellular [Ca(2+)] increases in human sperm even in the absence of extracellular Ca(2+). Using LysoTracker, a fluorescent probe that selectively accumulates in acidic compartments, we identified two such stores in human sperm cells. Their acidic nature was further confirmed by the reduction in staining intensity observed upon inhibition of the endo-lysosomal proton pump with Bafilomycin, or after lysosomal bursting with glycyl-l-phenylalanine-2-naphthylamide. The selective fluorescent NAADP analog, Ned-19, stained the same subcellular regions as LysoTracker, suggesting that these stores are the targets of NAADP action.
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Affiliation(s)
- A A Sánchez-Tusie
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - S R Vasudevan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, England, UK
| | - G C Churchill
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, England, UK
| | - T Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - C L Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
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30
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Jagannath A, Butler R, Godinho SIH, Couch Y, Brown LA, Vasudevan SR, Flanagan KC, Anthony D, Churchill GC, Wood MJA, Steiner G, Ebeling M, Hossbach M, Wettstein JG, Duffield GE, Gatti S, Hankins MW, Foster RG, Peirson SN. The CRTC1-SIK1 pathway regulates entrainment of the circadian clock. Cell 2013; 154:1100-1111. [PMID: 23993098 PMCID: PMC3898689 DOI: 10.1016/j.cell.2013.08.004] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 05/24/2013] [Accepted: 07/29/2013] [Indexed: 11/09/2022]
Abstract
Retinal photoreceptors entrain the circadian system to the solar day. This photic resetting involves cAMP response element binding protein (CREB)-mediated upregulation of Per genes within individual cells of the suprachiasmatic nuclei (SCN). Our detailed understanding of this pathway is poor, and it remains unclear why entrainment to a new time zone takes several days. By analyzing the light-regulated transcriptome of the SCN, we have identified a key role for salt inducible kinase 1 (SIK1) and CREB-regulated transcription coactivator 1 (CRTC1) in clock re-setting. An entrainment stimulus causes CRTC1 to coactivate CREB, inducing the expression of Per1 and Sik1. SIK1 then inhibits further shifts of the clock by phosphorylation and deactivation of CRTC1. Knockdown of Sik1 within the SCN results in increased behavioral phase shifts and rapid re-entrainment following experimental jet lag. Thus SIK1 provides negative feedback, acting to suppress the effects of light on the clock. This pathway provides a potential target for the regulation of circadian rhythms. Nocturnal light induces widespread transcriptional changes in the SCN The CRTC1-SIK1 cascade regulates entrainment of the circadian clock Negative feedback by SIK1 limits the effects of light on the clock Homeostatic regulation of entrainment ensures gradual adaptation to a new time zone
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Affiliation(s)
- Aarti Jagannath
- Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; pRED Pharma Research and Development F. Hoffmann-La Roche, 4070 Basel, Switzerland
| | - Rachel Butler
- Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; pRED Pharma Research and Development F. Hoffmann-La Roche, 4070 Basel, Switzerland
| | - Sofia I H Godinho
- Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; pRED Pharma Research and Development F. Hoffmann-La Roche, 4070 Basel, Switzerland
| | - Yvonne Couch
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Laurence A Brown
- Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| | - Sridhar R Vasudevan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Kevin C Flanagan
- Department of Biological Sciences, University of Notre Dame, Galvin Life Sciences Center, Notre Dame, IN 46556, USA
| | - Daniel Anthony
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Guido Steiner
- pRED Pharma Research and Development F. Hoffmann-La Roche, 4070 Basel, Switzerland
| | - Martin Ebeling
- pRED Pharma Research and Development F. Hoffmann-La Roche, 4070 Basel, Switzerland
| | - Markus Hossbach
- Axolabs GmbH Fritz-Hornschuch-Straße 9, 95326 Kulmbach, Germany
| | - Joseph G Wettstein
- pRED Pharma Research and Development F. Hoffmann-La Roche, 4070 Basel, Switzerland
| | - Giles E Duffield
- Department of Biological Sciences, University of Notre Dame, Galvin Life Sciences Center, Notre Dame, IN 46556, USA
| | - Silvia Gatti
- pRED Pharma Research and Development F. Hoffmann-La Roche, 4070 Basel, Switzerland
| | - Mark W Hankins
- Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| | - Russell G Foster
- Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK.
| | - Stuart N Peirson
- Nuffield Department of Clinical Neurosciences (Nuffield Laboratory of Ophthalmology), University of Oxford, Levels 5-6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK.
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Singh N, Halliday AC, Thomas JM, Kuznetsova OV, Baldwin R, Woon ECY, Aley PK, Antoniadou I, Sharp T, Vasudevan SR, Churchill GC. A safe lithium mimetic for bipolar disorder. Nat Commun 2013; 4:1332. [PMID: 23299882 PMCID: PMC3605789 DOI: 10.1038/ncomms2320] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 11/22/2012] [Indexed: 12/29/2022] Open
Abstract
Lithium is the most effective mood stabilizer for the treatment of bipolar disorder, but it is toxic at only twice the therapeutic dosage and has many undesirable side effects. It is likely that a small molecule could be found with lithium-like efficacy but without toxicity through target-based drug discovery; however, lithium’s therapeutic target remains equivocal. Inositol monophosphatase is a possible target but no bioavailable inhibitors exist. Here we report that the antioxidant ebselen inhibits inositol monophosphatase and induces lithium-like effects on mouse behaviour, which are reversed with inositol, consistent with a mechanism involving inhibition of inositol recycling. Ebselen is part of the National Institutes of Health Clinical Collection, a chemical library of bioavailable drugs considered clinically safe but without proven use. Therefore, ebselen represents a lithium mimetic with the potential both to validate inositol monophosphatase inhibition as a treatment for bipolar disorder and to serve as a treatment itself.
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Affiliation(s)
- Nisha Singh
- University of Oxford, Department of Pharmacology, Mansfield Road, Oxford OX1 3QT, UK
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32
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Singh N, Rosa AR, Whitaker E, Britto M, Lewis A, Vieta E, Churchill GC, Geddes JR, Goodwin GM. Relating mood to plasma glutathione and BDNF levels in patients with bipolar disorder. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.lb528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Nisha Singh
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | | | - Eleanor Whitaker
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Marianne Britto
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Alexander Lewis
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Edward Vieta
- University Hospital Clinic of BarcelonaBarcelonaSpain
| | | | - John R Geddes
- Department of PsychiatryUniversity of OxfordOxfordUnited Kingdom
| | - Guy M Goodwin
- Department of PsychiatryUniversity of OxfordOxfordUnited Kingdom
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33
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Morgan AJ, Davis LC, Wagner SKTY, Lewis AM, Parrington J, Churchill GC, Galione A. Bidirectional Ca²⁺ signaling occurs between the endoplasmic reticulum and acidic organelles. ACTA ACUST UNITED AC 2013; 200:789-805. [PMID: 23479744 PMCID: PMC3601362 DOI: 10.1083/jcb.201204078] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
After acidic organelles induce signaling to activate ER calcium ion release, local microdomains of high calcium at ER–acidic organelle junctions feed back to activate further acidic organelle calcium release. The endoplasmic reticulum (ER) and acidic organelles (endo-lysosomes) act as separate Ca2+ stores that release Ca2+ in response to the second messengers IP3 and cADPR (ER) or NAADP (acidic organelles). Typically, trigger Ca2+ released from acidic organelles by NAADP subsequently recruits IP3 or ryanodine receptors on the ER, an anterograde signal important for amplification and Ca2+ oscillations/waves. We therefore investigated whether the ER can signal back to acidic organelles, using organelle pH as a reporter of NAADP action. We show that Ca2+ released from the ER can activate the NAADP pathway in two ways: first, by stimulating Ca2+-dependent NAADP synthesis; second, by activating NAADP-regulated channels. Moreover, the differential effects of EGTA and BAPTA (slow and fast Ca2+ chelators, respectively) suggest that the acidic organelles are preferentially activated by local microdomains of high Ca2+ at junctions between the ER and acidic organelles. Bidirectional organelle communication may have wider implications for endo-lysosomal function as well as the generation of Ca2+ oscillations and waves.
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Affiliation(s)
- Anthony J Morgan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, England, UK.
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34
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Aley PK, Singh N, Brailoiu GC, Brailoiu E, Churchill GC. Nicotinic acid adenine dinucleotide phosphate (NAADP) is a second messenger in muscarinic receptor-induced contraction of guinea pig trachea. J Biol Chem 2013; 288:10986-93. [PMID: 23467410 DOI: 10.1074/jbc.m113.458620] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is increasingly being demonstrated to be involved in calcium signaling in many cell types and species. Although it has been shown to play a role in smooth muscle cell contraction in several tissues, nothing is known about its possible role in tracheal smooth muscle, a muscle type that is clinically relevant to asthma. To determine whether NAADP functions as a second messenger in tracheal smooth muscle contraction, we used the criteria set out by Sutherland for a molecule to be designated a second messenger. We report that NAADP satisfies all five criteria as follows. First, the NAADP antagonist Ned-19 inhibited contractions in tracheal rings and calcium increases in isolated smooth muscle cells induced by the muscarinic agonist carbachol. Second, NAADP increased cytosolic calcium in isolated cells when microinjected and was blocked by Ned-19. Third, tracheal homogenates could synthesize NAADP by base exchange from exogenous NADP and nicotinic acid and metabolize exogenous NAADP to nicotinic acid adenine dinucleotide by a 2'-phosphatase. Fourth, carbachol induced a rapid and transient increase in endogenous NAADP levels. Fifth, tracheal homogenates contained NAADP-binding sites of high affinity. Taken together, these data demonstrate that NAADP functions as a second messenger in tracheal smooth muscle, and therefore, steps in the NAADP signaling pathway might provide possible new drug targets.
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Affiliation(s)
- Parvinder K Aley
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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35
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Davis LC, Morgan AJ, Chen JL, Snead CM, Bloor-Young D, Shenderov E, Stanton-Humphreys MN, Conway SJ, Churchill GC, Parrington J, Cerundolo V, Galione A. NAADP activates two-pore channels on T cell cytolytic granules to stimulate exocytosis and killing. Curr Biol 2012. [PMID: 23177477 PMCID: PMC3525857 DOI: 10.1016/j.cub.2012.10.035] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A cytotoxic T lymphocyte (CTL) kills an infected or tumorigenic cell by Ca2+-dependent exocytosis of cytolytic granules at the immunological synapse formed between the two cells. Although inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ release from the endoplasmic reticulum activates the store-operated Ca2+-influx pathway that is necessary for exocytosis, it is not a sufficient stimulus [1–4]. Here we identify the Ca2+-mobilizing messenger nicotinic acid adenine dinucleotide phosphate (NAADP) and its recently identified molecular target, two-pore channels (TPCs) [5–7], as being important for T cell receptor signaling in CTLs. We demonstrate that cytolytic granules are not only reservoirs of cytolytic proteins but are also the acidic Ca2+ stores mobilized by NAADP via TPC channels on the granules themselves, so that TPCs migrate to the immunological synapse upon CTL activation. Moreover, NAADP activates TPCs to drive exocytosis in a way that is not mimicked by global Ca2+ signals induced by IP3 or ionomycin, suggesting that critical, local Ca2+ nanodomains around TPCs stimulate granule exocytosis. Hence, by virtue of the NAADP/TPC pathway, cytolytic granules generate Ca2+ signals that lead to their own exocytosis and to cell killing. This study highlights a selective role for NAADP in stimulating exocytosis crucial for immune cell function and may impact on stimulus-secretion coupling in wider cellular contexts.
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Affiliation(s)
- Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford, UK.
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36
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Singh N, Halliday AC, Knight M, Lack NA, Lowe E, Churchill GC. Cloning, expression, purification, crystallization and X-ray analysis of inositol monophosphatase from Mus musculus and Homo sapiens. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1149-52. [PMID: 23027737 PMCID: PMC3497969 DOI: 10.1107/s1744309112035191] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/08/2012] [Indexed: 11/10/2022]
Abstract
Inositol monophosphatase (IMPase) catalyses the hydrolysis of inositol monophosphate to inositol and is crucial in the phosphatidylinositol (PI) signalling pathway. Lithium, which is the drug of choice for bipolar disorder, inhibits IMPase at therapeutically relevant plasma concentrations. Both mouse IMPase 1 (MmIMPase 1) and human IMPase 1 (HsIMPase 1) were cloned into pRSET5a, expressed in Escherichia coli, purified and crystallized using the sitting-drop method. The structures were solved at resolutions of 2.4 and 1.7 Å, respectively. Comparison of MmIMPase 1 and HsIMPase 1 revealed a core r.m.s. deviation of 0.516 Å.
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Affiliation(s)
- Nisha Singh
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, England
| | - Amy C. Halliday
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, England
| | - Matthew Knight
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, England
| | - Nathan A. Lack
- Koç University School of Medicine, Rumelifeneri Yolu, Sarıyer, Istanbul, Turkey
| | - Edward Lowe
- Biochemistry Department, University of Oxford, Oxford OX1 3QU, England
| | - Grant C. Churchill
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, England
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37
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Lewis AM, Aley PK, Roomi A, Thomas JM, Masgrau R, Garnham C, Shipman K, Paramore C, Bloor-Young D, Sanders LEL, Terrar DA, Galione A, Churchill GC. β-Adrenergic receptor signaling increases NAADP and cADPR levels in the heart. Biochem Biophys Res Commun 2012; 427:326-9. [PMID: 22995315 DOI: 10.1016/j.bbrc.2012.09.054] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 09/10/2012] [Indexed: 10/27/2022]
Abstract
Evidence suggests that β-Adrenergic receptor signaling increases heart rate and force through not just cyclic AMP but also the Ca(2+)-releasing second messengers NAADP (nicotinic acid adenine dinucleotide phosphate) and cADPR (cyclic ADP-ribose). Nevertheless, proof of the physiological relevance of these messengers requires direct measurements of their levels in response to receptor stimulation. Here we report that in intact Langendorff-perfused hearts β-adrenergic stimulation increased both messengers, with NAADP being transient and cADPR being sustained. Both NAADP and cADPR have physiological and therefore pathological relevance by providing alternative drug targets in the β-adrenergic receptor signaling pathway.
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Affiliation(s)
- Alexander M Lewis
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
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Abstract
Reprofiling of existing drugs to treat conditions not originally targeted is an attractive means of addressing the problem of a decreasing stream of approved drugs. To determine if 3D shape similarity can be used to rationalize an otherwise serendipitous process, we employed 3D shape-based virtual screening to reprofile existing FDA-approved drugs. The study was conducted in two phases. First, multiple histamine H(1) receptor antagonists were identified to be used as query molecules, and these were compared to a database of approved drugs. Second, the hits were ranked according to 3D similarity and the top drugs evaluated in a cell-based assay. The virtual screening methodology proved highly successful, as 13 of 23 top drugs tested selectively inhibited histamine-induced calcium release with the best being chlorprothixene (IC(50) 1 nM). Finally, we confirmed that the drugs identified using the cell-based assay were all acting at the receptor level by conducting a radioligand-binding assay using rat membrane.
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Affiliation(s)
- Sridhar R Vasudevan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, United Kingdom.
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39
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Rosen D, Bloor-Young D, Squires J, Parkesh R, Waters G, Vasudevan SR, Lewis AM, Churchill GC. Synthesis and use of cell-permeant cyclic ADP-ribose. Biochem Biophys Res Commun 2012; 418:353-8. [PMID: 22274607 DOI: 10.1016/j.bbrc.2012.01.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 01/06/2012] [Indexed: 12/13/2022]
Abstract
Cyclic ADP-ribose (cADPR) is a second messenger that acts on ryanodine receptors to mobilize Ca(2+). cADPR has a net negative charge at physiological pH making it not passively membrane permeant thereby requiring it to be injected, electroporated or loaded via liposomes. Such membrane impermeance of other charged intracellular messengers (including cyclic AMP, inositol 1,4,5-trisphosphate and nicotinic acid adenine dinucleotide phosphate) and fluorescent dyes (including fura-2 and fluorescein) has been overcome by synthesizing masked analogs (prodrugs), which are passively permeant and hydrolyzed to the parent compound inside cells. We now report the synthesis and biological activity of acetoxymethyl (AM) and butoxymethyl (BM) analogs of cADPR. Extracellular addition of cADPR-AM or cADPR-BM to neuronal cells in primary culture or PC12 neuroblastoma cells induced increases in cytosolic Ca(2+). Pre-incubation of PC12 cells with thapsigargin, ryanodine or caffeine eliminated the response to cADPR-AM, whereas the response still occurred in the absence of extracellular Ca(2+). Combined, these data demonstrate that masked cADPR analogs are cell-permeant and biologically active. We hope these cell-permeant tools will facilitate cADPR research and reveal its diverse physiological functions.
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Affiliation(s)
- Daniel Rosen
- University of Oxford, Department of Pharmacology, Mansfield Road, Oxford OX1 3QT, UK
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40
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Bayliss RA, Bloor-Young D, Churchill GC, Terrar DA. NAADP is a Physiologically-Relevant Calcium Mobilising Compound in Atrial Myocytes. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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41
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Gómez-Suaga P, Luzón-Toro B, Churamani D, Zhang L, Bloor-Young D, Patel S, Woodman PG, Churchill GC, Hilfiker S. Leucine-rich repeat kinase 2 regulates autophagy through a calcium-dependent pathway involving NAADP. Hum Mol Genet 2011; 21:511-25. [PMID: 22012985 PMCID: PMC3259011 DOI: 10.1093/hmg/ddr481] [Citation(s) in RCA: 249] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mutations in the leucine-rich repeat kinase-2 (LRRK2) gene cause late-onset Parkinson’s disease, but its physiological function has remained largely unknown. Here we report that LRRK2 activates a calcium-dependent protein kinase kinase-β (CaMKK-β)/adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway which is followed by a persistent increase in autophagosome formation. Simultaneously, LRKR2 overexpression increases the levels of the autophagy receptor p62 in a protein synthesis-dependent manner, and decreases the number of acidic lysosomes. The LRRK2-mediated effects result in increased sensitivity of cells to stressors associated with abnormal protein degradation. These effects can be mimicked by the lysosomal Ca2+-mobilizing messenger nicotinic acid adenine dinucleotide phosphate (NAADP) and can be reverted by an NAADP receptor antagonist or expression of dominant-negative receptor constructs. Collectively, our data indicate a molecular mechanism for LRRK2 deregulation of autophagy and reveal previously unidentified therapeutic targets.
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Affiliation(s)
- Patricia Gómez-Suaga
- Institute of Parasitology and Biomedicine ‘López-Neyra’, Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18100 Granada, Spain
| | - Berta Luzón-Toro
- Institute of Parasitology and Biomedicine ‘López-Neyra’, Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18100 Granada, Spain
| | - Dev Churamani
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Ling Zhang
- Faculty of Life Sciences, University of Manchester, Manchester, UK and
| | | | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Philip G. Woodman
- Faculty of Life Sciences, University of Manchester, Manchester, UK and
| | | | - Sabine Hilfiker
- Institute of Parasitology and Biomedicine ‘López-Neyra’, Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18100 Granada, Spain
- To whom correspondence should be addressed. Tel: +34 958181654; Fax: +34 958181632;
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42
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Collins TP, Bayliss R, Churchill GC, Galione A, Terrar DA. NAADP influences excitation-contraction coupling by releasing calcium from lysosomes in atrial myocytes. Cell Calcium 2011; 50:449-58. [PMID: 21906808 DOI: 10.1016/j.ceca.2011.07.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 07/18/2011] [Accepted: 07/26/2011] [Indexed: 10/17/2022]
Abstract
In atrial myocytes, the sarcoplasmic reticulum (SR) has an essential role in regulating the force of contraction as a consequence of its involvement in excitation-contraction coupling (ECC). Nicotinic acid adenine dinucleotide phosphate (NAADP) is a Ca(2+) mobilizing messenger that acts to release Ca(2+) from an acidic store in mammalian cells. The photorelease of NAADP in atrial myocytes increased Ca(2+) transient amplitude with no effect on accompanying action potentials or the L-type Ca(2+) current. NAADP-AM, a cell permeant form of NAADP, increased Ca(2+) spark amplitude and frequency. The effect on Ca(2+) spark frequency could be prevented by bafilomycin A1, a vacuolar H(+)-ATPase inhibitor, or by disruption of lysosomes by GPN. Bafilomycin prevented staining of acidic stores with LysoTracker red by increasing lysosomal pH. NAADP-AM also produced an increase in the lysosomal pH, as detected by a reduction in LysoSensor green fluorescence. These effects of NAADP were associated with an increase in the amount of caffeine-releasable Ca(2+) in the SR and may be regulated by β-adrenoceptor stimulation with isoprenaline. These observations are consistent with a role for NAADP in regulating ECC in atrial myocytes by releasing Ca(2+) from an acidic store, which enhances SR Ca(2+) release by increasing SR load.
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Affiliation(s)
- Thomas P Collins
- Department of Pharmacology, University of Oxford, Mansfield Road, UK.
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43
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Barceló-Torns M, Lewis AM, Gubern A, Barneda D, Bloor-Young D, Picatoste F, Churchill GC, Claro E, Masgrau R. NAADP mediates ATP-induced Ca2+ signals in astrocytes. FEBS Lett 2011; 585:2300-6. [PMID: 21664355 DOI: 10.1016/j.febslet.2011.05.062] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 11/17/2022]
Abstract
Intracellular Ca(2+) signals provide astrocytes with a specific form of excitability that enables them to regulate synaptic transmission. In this study, we demonstrate that NAADP-AM, a membrane-permeant analogue of the new second messenger nicotinic acid-adenine dinucleotide phosphate (NAADP), mobilizes Ca(2+) in astrocytes and that the response is blocked by Ned-19, an antagonist of NAADP signalling. We also show that NAADP receptors are expressed in lysosome-related acidic vesicles. Pharmacological disruption of either NAADP or lysosomal signalling reduced Ca(2+) responses induced by ATP and endothelin-1, but not by bradykinin. Furthermore, ATP increased endogenous NAADP levels. Overall, our data provide evidence for NAADP being an intracellular messenger for agonist-mediated calcium signalling in astrocytes.
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Affiliation(s)
- Miquel Barceló-Torns
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
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44
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Brailoiu GC, Gurzu B, Gao X, Parkesh R, Aley PK, Trifa DI, Galione A, Dun NJ, Madesh M, Patel S, Churchill GC, Brailoiu E. Acidic NAADP-sensitive calcium stores in the endothelium: agonist-specific recruitment and role in regulating blood pressure. J Biol Chem 2010; 285:37133-7. [PMID: 20876534 DOI: 10.1074/jbc.c110.169763] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Accumulating evidence implicates nicotinic acid adenine dinucleotide phosphate (NAADP) in the control of Ca(2+)-dependent functions. Little, however, is known concerning its role in the vascular endothelium, a major regulator of blood pressure. Here, we show that NAADP acetoxymethyl ester (NAADP-AM), a cell-permeant NAADP analog, increases cytosolic Ca(2+) concentration in aortic endothelial cells. We demonstrate that these signals and those evoked by acetylcholine are blocked by disrupting acidic organelles with bafilomycin A1. In contrast, Ca(2+) signals in response to thrombin are only partially inhibited by bafilomycin A1 treatment, and those to ATP were insensitive, suggesting that recruitment of acidic stores is agonist-specific. We further show that NAADP-evoked Ca(2+) signals hyperpolarize endothelial cells and generate NO. Additionally, we demonstrate that NAADP dilates aortic rings in an endothelium- and NO-dependent manner. Finally, we show that intravenous administration of NAADP-AM into anesthetized rats decreases mean arterial pressure. Our data extend the actions of NAADP to the endothelium both in vitro and in vivo, pointing to a previously unrecognized role for this messenger in controlling blood pressure.
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Affiliation(s)
- G Cristina Brailoiu
- Departments of Pharmacology, University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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45
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Pitt SJ, Funnell TM, Sitsapesan M, Venturi E, Rietdorf K, Ruas M, Ganesan A, Gosain R, Churchill GC, Zhu MX, Parrington J, Galione A, Sitsapesan R. TPC2 is a novel NAADP-sensitive Ca2+ release channel, operating as a dual sensor of luminal pH and Ca2+. J Biol Chem 2010; 285:35039-46. [PMID: 20720007 PMCID: PMC2966118 DOI: 10.1074/jbc.m110.156927] [Citation(s) in RCA: 176] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a molecule capable of initiating the release of intracellular Ca2+ required for many essential cellular processes. Recent evidence links two-pore channels (TPCs) with NAADP-induced release of Ca2+ from lysosome-like acidic organelles; however, there has been no direct demonstration that TPCs can act as NAADP-sensitive Ca2+ release channels. Controversial evidence also proposes ryanodine receptors as the primary target of NAADP. We show that TPC2, the major lysosomal targeted isoform, is a cation channel with selectivity for Ca2+ that will enable it to act as a Ca2+ release channel in the cellular environment. NAADP opens TPC2 channels in a concentration-dependent manner, binding to high affinity activation and low affinity inhibition sites. At the core of this process is the luminal environment of the channel. The sensitivity of TPC2 to NAADP is steeply dependent on the luminal [Ca2+] allowing extremely low levels of NAADP to open the channel. In parallel, luminal pH controls NAADP affinity for TPC2 by switching from reversible activation of TPC2 at low pH to irreversible activation at neutral pH. Further evidence earmarking TPCs as the likely pathway for NAADP-induced intracellular Ca2+ release is obtained from the use of Ned-19, the selective blocker of cellular NAADP-induced Ca2+ release. Ned-19 antagonizes NAADP-activation of TPC2 in a non-competitive manner at 1 μm but potentiates NAADP activation at nanomolar concentrations. This single-channel study provides a long awaited molecular basis for the peculiar mechanistic features of NAADP signaling and a framework for understanding how NAADP can mediate key physiological events.
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Affiliation(s)
- Samantha J Pitt
- School of Physiology and Pharmacology, Medical Sciences Building, and Center for Nanoscience and Quantum Information, University of Bristol, Bristol BS8 1TD, United Kingdom
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46
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Vasudevan SR, Lewis AM, Chan JW, Machin CL, Sinha D, Galione A, Churchill GC. The calcium-mobilizing messenger nicotinic acid adenine dinucleotide phosphate participates in sperm activation by mediating the acrosome reaction. J Biol Chem 2010; 285:18262-9. [PMID: 20400502 PMCID: PMC2881750 DOI: 10.1074/jbc.m109.087858] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Before a sperm can fertilize an egg it must undergo a final activation step induced by the egg termed the acrosome reaction. During the acrosome reaction a lysosome-related organelle, the acrosome, fuses with the plasma membrane to release hydrolytic enzymes and expose an egg-binding protein. Because NAADP (nicotinic acid adenine dinucleotide phosphate) releases Ca2+ from acidic lysosome-related organelles in other cell types, we investigated a possible role for NAADP in mediating the acrosome reaction. We report that NAADP binds with high affinity to permeabilized sea urchin sperm. Moreover, we used Mn2+ quenching of luminal fura-2 and 45Ca2+ to directly demonstrate NAADP regulation of a cation channel on the acrosome. Additionally, we show that NAADP synthesis occurs through base exchange and is driven by an increase in Ca2+. We propose a new model for acrosome reaction signaling in which Ca2+ influx initiated by egg jelly stimulates NAADP synthesis and that this NAADP acts on its receptor/channel on the acrosome to release Ca2+ to drive acrosomal exocytosis.
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Affiliation(s)
- Sridhar R Vasudevan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
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47
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Ruas M, Rietdorf K, Arredouani A, Davis LC, Lloyd-Evans E, Koegel H, Funnell TM, Morgan AJ, Ward JA, Watanabe K, Cheng X, Churchill GC, Zhu MX, Platt FM, Wessel GM, Parrington J, Galione A. Purified TPC isoforms form NAADP receptors with distinct roles for Ca(2+) signaling and endolysosomal trafficking. Curr Biol 2010; 20:703-9. [PMID: 20346675 PMCID: PMC2861162 DOI: 10.1016/j.cub.2010.02.049] [Citation(s) in RCA: 214] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 01/07/2010] [Accepted: 02/09/2010] [Indexed: 11/29/2022]
Abstract
Intracellular Ca2+ signals constitute key elements in signal transduction. Of the three major Ca2+ mobilizing messengers described, the most potent, nicotinic acid adenine dinucleotide phosphate (NAADP) is the least well understood in terms of its molecular targets [1]. Recently, we showed that heterologous expression of two-pore channel (TPC) proteins enhances NAADP-induced Ca2+ release, whereas the NAADP response was abolished in pancreatic beta cells from Tpcn2 gene knockout mice [2]. However, whether TPCs constitute native NAADP receptors is unclear. Here we show that immunopurified endogenous TPC complexes possess the hallmark properties ascribed to NAADP receptors, including nanomolar ligand affinity [3–5]. Our study also reveals important functional differences between the three TPC isoforms. Thus, TPC1 and TPC2 both mediate NAADP-induced Ca2+ release, but the subsequent amplification of this trigger Ca2+ by IP3Rs is more tightly coupled for TPC2. In contrast, TPC3 expression suppressed NAADP-induced Ca2+ release. Finally, increased TPC expression has dramatic and contrasting effects on endolysosomal structures and dynamics, implicating a role for NAADP in the regulation of vesicular trafficking. We propose that NAADP regulates endolysosomal Ca2+ storage and release via TPCs and coordinates endoplasmic reticulum Ca2+ release in a role that impacts on Ca2+ signaling in health and disease [6].
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Affiliation(s)
- Margarida Ruas
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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48
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Aley PK, Noh HJ, Gao X, Tica AA, Brailoiu E, Churchill GC. A functional role for nicotinic acid adenine dinucleotide phosphate in oxytocin-mediated contraction of uterine smooth muscle from rat. J Pharmacol Exp Ther 2010; 333:726-35. [PMID: 20304938 DOI: 10.1124/jpet.110.165837] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Conventionally, G protein-coupled receptors are thought to increase calcium via inositol 1,4,5-trisphosphate (InsP(3)). More recent evidence shows that an alternative second messenger, nicotinic acid adenine dinucleotide phosphate (NAADP), also has a role to play, causing researchers to question established calcium releasing pathways. With the recent development, by our group, of cell-permeant NAADP (NAADP-aceteoxymethyl ester) and a selective NAADP receptor antagonist (Ned-19; 1-(3-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-4-methoxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid),the ability to investigate this signaling pathway has improved. Therefore, we investigated a role for NAADP in oxytocin-mediated responses in the rat uterus. Oxytocin- and NAADP-mediated effects were investigated by using contractile measurements of whole uterine strips from rat in organ baths. Responses were correlated to calcium release in cultured rat uterine smooth muscle cells measured by fluorescence microscopy. Inhibition of both oxytocin-induced contraction and calcium release by the traditional NAADP-signaling disrupter bafilomycin and the NAADP receptor antagonist Ned-19 clearly demonstrated a role for NAADP in oxytocin-induced signaling. A cell-permeant form of NAADP was able to produce both uterine contractions and calcium release. This response was unaffected by depletion of sarcoplasmic reticulum stores with thapsigargin, but was abolished by both bafilomycin and Ned-19. Crucially, oxytocin stimulated an increase in NAADP in rat uterine tissue. The present study demonstrates directly that NAADP signaling plays a role in rat uterine contractions. Moreover, investigation of this signaling pathway highlights yet another component of oxytocin-mediated signaling, stressing the need to consider the action of new components as they are discovered, even in signaling pathways that are thought to be well established.
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Affiliation(s)
- Parvinder K Aley
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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49
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Dickinson GD, Churchill GC, Brailoiu E, Patel S. Deviant nicotinic acid adenine dinucleotide phosphate (NAADP)-mediated Ca2+ signaling upon lysosome proliferation. J Biol Chem 2010; 285:13321-5. [PMID: 20231291 DOI: 10.1074/jbc.c110.112573] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Accumulating evidence suggests that the endolysosomal system is a novel intracellular Ca(2+) pool mobilized by the second messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). Although lysosomes in neurons are known to proliferate in numerous neurodegenerative diseases and during the normal course of aging, little is known concerning the effect of lysosomal proliferation on Ca(2+) homeostasis. Here, we induce proliferation of lysosomes in primary cultures of rat hippocampal neurons and PC12 cells through chronic treatment with the cathepsin inhibitor, Z-Phe-Ala-diazomethylketone. We demonstrate that lysosome proliferation increases the size of the lysosomal Ca(2+) pool and enhances Ca(2+) signals in response to direct cellular delivery of NAADP and glutamate, an identified NAADP-producing agonist. Our data suggest that deregulated lysosomal Ca(2+) signaling through NAADP may contribute to neuronal dysfunction and highlight the usefulness of lysosomal hydrolase inhibition in probing NAADP action.
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Affiliation(s)
- George D Dickinson
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
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50
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Rosen D, Lewis AM, Mizote A, Thomas JM, Aley PK, Vasudevan SR, Parkesh R, Galione A, Izumi M, Ganesan A, Churchill GC. Analogues of the nicotinic acid adenine dinucleotide phosphate (NAADP) antagonist Ned-19 indicate two binding sites on the NAADP receptor. J Biol Chem 2009; 284:34930-4. [PMID: 19826006 DOI: 10.1074/jbc.m109.016519] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a Ca(2+)-releasing messenger. Biological data suggest that its receptor has two binding sites: one high-affinity locking site and one low-affinity opening site. To directly address the presence and function of these putative binding sites, we synthesized and tested analogues of the NAADP antagonist Ned-19. Ned-19 itself inhibits both NAADP-mediated Ca(2+) release and NAADP binding. A fluorometry bioassay was used to assess NAADP-mediated Ca(2+) release, whereas a radioreceptor assay was used to assess binding to the NAADP receptor (only at the high-affinity site). In Ned-20, the fluorine is para rather than ortho as in Ned-19. Ned-20 does not inhibit NAADP-mediated Ca(2+) release but inhibits NAADP binding. Conversely, Ned-19.4 (a methyl ester of Ned-19) inhibits NAADP-mediated Ca(2+) release but cannot inhibit NAADP binding. Furthermore, Ned-20 prevents the self-desensitization response characteristic of NAADP in sea urchin eggs, confirming that this response is mediated by a high-affinity allosteric site to which NAADP binds in the radioreceptor assay. Collectively, these data provide the first direct evidence for two binding sites (one high- and one low-affinity) on the NAADP receptor.
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Affiliation(s)
- Daniel Rosen
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
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