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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] [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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2
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Case KC, Salsaa M, Yu W, Greenberg ML. Regulation of Inositol Biosynthesis: Balancing Health and Pathophysiology. Handb Exp Pharmacol 2020; 259:221-260. [PMID: 30591968 DOI: 10.1007/164_2018_181] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Inositol is the precursor for all inositol compounds and is essential for viability of eukaryotic cells. Numerous cellular processes and signaling functions are dependent on inositol compounds, and perturbation of their synthesis leads to a wide range of human diseases. Although considerable research has been directed at understanding the function of inositol compounds, especially phosphoinositides and inositol phosphates, a focus on regulatory and homeostatic mechanisms controlling inositol biosynthesis has been largely neglected. Consequently, little is known about how synthesis of inositol is regulated in human cells. Identifying physiological regulators of inositol synthesis and elucidating the molecular mechanisms that regulate inositol synthesis will contribute fundamental insight into cellular processes that are mediated by inositol compounds and will provide a foundation to understand numerous disease processes that result from perturbation of inositol homeostasis. In addition, elucidating the mechanisms of action of inositol-depleting drugs may suggest new strategies for the design of second-generation pharmaceuticals to treat psychiatric disorders and other illnesses.
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Affiliation(s)
- Kendall C Case
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Michael Salsaa
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Wenxi Yu
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA.
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3
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Multiple molecular pathways stimulating macroautophagy protect from alpha-synuclein-induced toxicity in human neurons. Neuropharmacology 2019; 149:13-26. [DOI: 10.1016/j.neuropharm.2019.01.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 01/16/2019] [Accepted: 01/20/2019] [Indexed: 12/16/2022]
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4
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Heron PW, Abellán-Flos M, Salmon L, Sygusch J. Bisphosphonate Inhibitors of Mammalian Glycolytic Aldolase. J Med Chem 2018; 61:10558-10572. [PMID: 30418024 DOI: 10.1021/acs.jmedchem.8b01000] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The glycolytic enzyme aldolase is an emerging drug target in diseases such as cancer and protozoan infections which are dependent on a hyperglycolytic phenotype to synthesize adenosine 5'-triphosphate and metabolic precursors for biomass production. To date, structural information for the enzyme in complex with phosphate-derived inhibitors has been lacking. Thus, we determined the crystal structure of mammalian aldolase in complex with naphthalene 2,6-bisphosphate (1) that served as a template for the design of bisphosphonate-based inhibitors, namely, 2-phosphate-naphthalene 6-bisphosphonate (2), 2-naphthol 6-bisphosphonate (3), and 1-phosphate-benzene 4-bisphosphonate (4). All inhibitors targeted the active site, and the most promising lead, 2, exhibited slow-binding inhibition with an overall inhibition constant of ∼38 nM. Compound 2 inhibited proliferation of HeLa cancer cells, whereas HEK293 cells expressing a normal phenotype were not inhibited. The crystal structures delineated the essential features of high-affinity phosphate-derived inhibitors and provide a template for the development of inhibitors with prophylaxis potential.
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Affiliation(s)
- Paul W Heron
- Département de Biochimie et Médecine Moléculaire , Université de Montréal , CP 6128, Succursale Centre-Ville, Montréal , Québec H3C 3J7 , Canada
| | - Marta Abellán-Flos
- Equipe de Chimie Bioorganique et Bioinorganique, Institut de Chimie Moléculaire et des Matériaux D'Orsay (ICMMO) , Univ Paris-Saclay, Univ Paris-Sud, CNRS UMR8182, LabEx LERMIT , rue du doyen Georges Poitou , F-91405 Orsay , France
| | - Laurent Salmon
- Equipe de Chimie Bioorganique et Bioinorganique, Institut de Chimie Moléculaire et des Matériaux D'Orsay (ICMMO) , Univ Paris-Saclay, Univ Paris-Sud, CNRS UMR8182, LabEx LERMIT , rue du doyen Georges Poitou , F-91405 Orsay , France
| | - Jurgen Sygusch
- Département de Biochimie et Médecine Moléculaire , Université de Montréal , CP 6128, Succursale Centre-Ville, Montréal , Québec H3C 3J7 , Canada
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5
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Kraft L, Roe SM, Gill R, Atack JR. Co-crystallization of human inositol monophosphatase with the lithium mimetic L-690,330. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2018; 74:973-978. [PMID: 30289407 DOI: 10.1107/s2059798318010380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/18/2018] [Indexed: 11/10/2022]
Abstract
Lithium, which is still the gold standard in the treatment of bipolar disorder, has been proposed to inhibit inositol monophosphatase (IMPase) and is hypothesized to exert its therapeutic effects by attenuating phosphatidylinositol (PI) cell signalling. Drug-discovery efforts have focused on small-molecule lithium mimetics that would specifically inhibit IMPase without exhibiting the undesired side effects of lithium. L-690,330 is a potent bisphosphonate substrate-based inhibitor developed by Merck Sharp & Dohme. To aid future structure-based inhibitor design, determination of the exact binding mechanism of L-690,330 to IMPase was of interest. Here, the high-resolution X-ray structure of human IMPase in complex with L690,330 and manganese ions determined at 1.39 Å resolution is reported.
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Affiliation(s)
- Lucas Kraft
- Sussex Drug Discovery Centre, University of Sussex, Chichester II, Falmer, Brighton BN1 9QJ, England
| | - S Mark Roe
- University of Sussex, Arundel Building, Falmer, Brighton BN1 9QJ, England
| | - Raj Gill
- Sussex Drug Discovery Centre, University of Sussex, Chichester II, Falmer, Brighton BN1 9QJ, England
| | - John R Atack
- School of Biosciences, Medicines Discovery Institute, Park Place, Cardiff CF10 3AT, Wales
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Kerr F, Bjedov I, Sofola-Adesakin O. Molecular Mechanisms of Lithium Action: Switching the Light on Multiple Targets for Dementia Using Animal Models. Front Mol Neurosci 2018; 11:297. [PMID: 30210290 PMCID: PMC6121012 DOI: 10.3389/fnmol.2018.00297] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/03/2018] [Indexed: 12/12/2022] Open
Abstract
Lithium has long been used for the treatment of psychiatric disorders, due to its robust beneficial effect as a mood stabilizing drug. Lithium’s effectiveness for improving neurological function is therefore well-described, stimulating the investigation of its potential use in several neurodegenerative conditions including Alzheimer’s (AD), Parkinson’s (PD) and Huntington’s (HD) diseases. A narrow therapeutic window for these effects, however, has led to concerted efforts to understand the molecular mechanisms of lithium action in the brain, in order to develop more selective treatments that harness its neuroprotective potential whilst limiting contraindications. Animal models have proven pivotal in these studies, with lithium displaying advantageous effects on behavior across species, including worms (C. elegans), zebrafish (Danio rerio), fruit flies (Drosophila melanogaster) and rodents. Due to their susceptibility to genetic manipulation, functional genomic analyses in these model organisms have provided evidence for the main molecular determinants of lithium action, including inhibition of inositol monophosphatase (IMPA) and glycogen synthase kinase-3 (GSK-3). Accumulating pre-clinical evidence has indeed provided a basis for research into the therapeutic use of lithium for the treatment of dementia, an area of medical priority due to its increasing global impact and lack of disease-modifying drugs. Although lithium has been extensively described to prevent AD-associated amyloid and tau pathologies, this review article will focus on generic mechanisms by which lithium preserves neuronal function and improves memory in animal models of dementia. Of these, evidence from worms, flies and mice points to GSK-3 as the most robust mediator of lithium’s neuro-protective effect, but it’s interaction with downstream pathways, including Wnt/β-catenin, CREB/brain-derived neurotrophic factor (BDNF), nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and toll-like receptor 4 (TLR4)/nuclear factor-κB (NFκB), have identified multiple targets for development of drugs which harness lithium’s neurogenic, cytoprotective, synaptic maintenance, anti-oxidant, anti-inflammatory and protein homeostasis properties, in addition to more potent and selective GSK-3 inhibitors. Lithium, therefore, has advantages as a multi-functional therapy to combat the complex molecular pathology of dementia. Animal studies will be vital, however, for comparative analyses to determine which of these defense mechanisms are most required to slow-down cognitive decline in dementia, and whether combination therapies can synergize systems to exploit lithium’s neuro-protective power while avoiding deleterious toxicity.
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Affiliation(s)
- Fiona Kerr
- Department of Life Sciences, School of Health & Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | - Ivana Bjedov
- UCL Cancer Institute, University College London, London, United Kingdom
| | - Oyinkan Sofola-Adesakin
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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7
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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] [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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8
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Lei P, Ayton S, Appukuttan AT, Moon S, Duce JA, Volitakis I, Cherny R, Wood SJ, Greenough M, Berger G, Pantelis C, McGorry P, Yung A, Finkelstein DI, Bush AI. Lithium suppression of tau induces brain iron accumulation and neurodegeneration. Mol Psychiatry 2017; 22:396-406. [PMID: 27400857 DOI: 10.1038/mp.2016.96] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/25/2016] [Accepted: 05/09/2016] [Indexed: 02/05/2023]
Abstract
Lithium is a first-line therapy for bipolar affective disorder. However, various adverse effects, including a Parkinson-like hand tremor, often limit its use. The understanding of the neurobiological basis of these side effects is still very limited. Nigral iron elevation is also a feature of Parkinsonian degeneration that may be related to soluble tau reduction. We found that magnetic resonance imaging T2 relaxation time changes in subjects commenced on lithium therapy were consistent with iron elevation. In mice, lithium treatment lowers brain tau levels and increases nigral and cortical iron elevation that is closely associated with neurodegeneration, cognitive loss and parkinsonian features. In neuronal cultures lithium attenuates iron efflux by lowering tau protein that traffics amyloid precursor protein to facilitate iron efflux. Thus, tau- and amyloid protein precursor-knockout mice were protected against lithium-induced iron elevation and neurotoxicity. These findings challenge the appropriateness of lithium as a potential treatment for disorders where brain iron is elevated (for example, Alzheimer's disease), and may explain lithium-associated motor symptoms in susceptible patients.
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Affiliation(s)
- P Lei
- Department of Neurology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Sichuan, China.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - S Ayton
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - A T Appukuttan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - S Moon
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - J A Duce
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, West Yorkshire, UK
| | - I Volitakis
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - R Cherny
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - S J Wood
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,School of Psychology, University of Birmingham, Birmingham, UK
| | - M Greenough
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - G Berger
- ORYGEN Research Centre, University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,Department of Child and Adolescent Psychiatry, University of Zürich, Zurich, Switzerland
| | - C Pantelis
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,Centre for Neural Engineering, Department of Electrical and Electronic Engineering, University of Melbourne, Parkville, VIC, Australia
| | - P McGorry
- ORYGEN Research Centre, University of Melbourne and Melbourne Health, Parkville, VIC, Australia
| | - A Yung
- Institute of Brain, Behaviour and Mental Health, University of Manchester and Greater Manchester West NHS Mental Health Trust, Manchester, UK
| | - D I Finkelstein
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - A I Bush
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
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9
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Kruczek J, Chiu SW, Jakobsson E, Pandit SA. Effects of Lithium and Other Monovalent Ions on Palmitoyl Oleoyl Phosphatidylcholine Bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1105-1115. [PMID: 28076953 DOI: 10.1021/acs.langmuir.6b04166] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Interactions of monovalent salts with lipid membranes are explored with molecular dynamics (MD) simulations. The simulations included the monovalent ions Na+ and K+, for their importance in physiology, Li+ for its small size and importance in several medical conditions including bipolar disorder, and Rb+ for its large size. All simulations included Cl- as counterions. One bilayer was simulated without salt as a control. Palmitoyl oleoyl phosphatidylcholine (POPC) bilayers experienced reductions in area per lipid with the addition of salt; the smaller the ion the smaller the area, with the exception of Li+. Li+ exhibited unique binding affinities between phosphates and sn-2 carbonyls that lowered the order of the top part of sn-2 chain, which increased the area per lipid, compared to other ionic simulations. Further, we observe that monovalent salts alter bilayer properties through structural changes and not so much through the changes in surface potential.
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Affiliation(s)
- James Kruczek
- Department of Physics, University of South Florida , Tampa, Florida 33620, United States
| | | | | | - Sagar A Pandit
- Department of Physics, University of South Florida , Tampa, Florida 33620, United States
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10
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Lithium-Responsive Seizure-Like Hyperexcitability Is Caused by a Mutation in the Drosophila Voltage-Gated Sodium Channel Gene paralytic. eNeuro 2016; 3:eN-NWR-0221-16. [PMID: 27844061 PMCID: PMC5103163 DOI: 10.1523/eneuro.0221-16.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/06/2016] [Indexed: 01/01/2023] Open
Abstract
Shudderer (Shu) is an X-linked dominant mutation in Drosophila melanogaster identified more than 40 years ago. A previous study showed that Shu caused spontaneous tremors and defects in reactive climbing behavior, and that these phenotypes were significantly suppressed when mutants were fed food containing lithium, a mood stabilizer used in the treatment of bipolar disorder (Williamson, 1982). This unique observation suggested that the Shu mutation affects genes involved in lithium-responsive neurobiological processes. In the present study, we identified Shu as a novel mutant allele of the voltage-gated sodium (Nav) channel gene paralytic (para). Given that hypomorphic para alleles and RNA interference-mediated para knockdown reduced the severity of Shu phenotypes, Shu was classified as a para hypermorphic allele. We also demonstrated that lithium could improve the behavioral abnormalities displayed by other Nav mutants, including a fly model of the human generalized epilepsy with febrile seizures plus. Our electrophysiological analysis of Shu showed that lithium treatment did not acutely suppress Nav channel activity, indicating that the rescue effect of lithium resulted from chronic physiological adjustments to this drug. Microarray analysis revealed that lithium significantly alters the expression of various genes in Shu, including those involved in innate immune responses, amino acid metabolism, and oxidation-reduction processes, raising the interesting possibility that lithium-induced modulation of these biological pathways may contribute to such adjustments. Overall, our findings demonstrate that Nav channel mutants in Drosophila are valuable genetic tools for elucidating the effects of lithium on the nervous system in the context of neurophysiology and behavior.
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11
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Petibone DM, Majeed W, Casciano DA. Autophagy function and its relationship to pathology, clinical applications, drug metabolism and toxicity. J Appl Toxicol 2016; 37:23-37. [PMID: 27682190 DOI: 10.1002/jat.3393] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 08/30/2016] [Accepted: 08/30/2016] [Indexed: 12/19/2022]
Abstract
Autophagy is a cellular process that facilitates nutrient turnover and removal of expended macromolecules and organelles to maintain homeostasis. The recycling of cytosolic macromolecules and damaged organelles by autophagosomes occurs through the lysosomal degradation pathway. Autophagy can also be upregulated as a prosurvival pathway in response to stress stimuli such as starvation, hypoxia or cell damage. Over the last two decades, there has been a surge in research revealing the basic molecular mechanisms of autophagy in mammalian cells. A corollary of an advanced understanding of autophagy has been a concurrent expansion of research into understanding autophagic function and dysfunction in pathology. Recent studies have revealed a pivotal role for autophagy in drug toxicity, and for utilizing autophagic components as diagnostic markers and therapeutic targets in treating disease and cancer. In this review, advances in understanding the molecular basis of mammalian autophagy, methods used to induce and evaluate autophagy, and the diverse interactions between autophagy and drug toxicity, disease progression and carcinogenesis are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Dayton M Petibone
- National Center for Toxicological Research, US FDA, Division of Genetic and Molecular Toxicology, Jefferson, AR, 72079, USA
| | - Waqar Majeed
- Center of Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
| | - Daniel A Casciano
- Center of Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
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12
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Zheng W, Brandish PE, Kolodin DG, Scolnick EM, Strulovici B. High-Throughput Cell-Based Screening Using Scintillation Proximity Assay for the Discovery of Inositol Phosphatase Inhibitors. ACTA ACUST UNITED AC 2016; 9:132-40. [PMID: 15006136 DOI: 10.1177/1087057103261039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inositol monophosphatase is a potential drug target for developing lithium-mimetic agents for the treatment of bipolar disorder. Enzyme-based assays have been traditionally used in compound screening to identify inositol monophosphatase inhibitors. A cell-based screening assay in which the compound needs to cross the cell membrane before reaching the target enzyme offers a new approach for discovering novel structure leads of the inositol monophosphatase inhibitor. The authors have recently reported a high-throughput measurement of G-protein-coupled receptor activation by determining inositol phosphates in cell extracts using scintillation proximity assay. This cell-based assay has been modified to allow the determination of inositol monophosphatase activity instead of G-protein-coupled receptors. The enzyme is also assayed in its native form and physiological environment. The authors have applied this cell-based assay to the high-throughput screening of a large compound collection and identified several novel inositol monophosphatase inhibitors. ( Journal of Biomolecular Screening 2004:132-140)
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Affiliation(s)
- Wei Zheng
- Department of Automated Biotechnology, Merck & Co., North Wales, PA 19454, USA.
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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] [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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Regulation of autophagy by mTOR-dependent and mTOR-independent pathways: autophagy dysfunction in neurodegenerative diseases and therapeutic application of autophagy enhancers. Biochem Soc Trans 2014; 41:1103-30. [PMID: 24059496 DOI: 10.1042/bst20130134] [Citation(s) in RCA: 274] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autophagy is an intracellular degradation pathway essential for cellular and energy homoeostasis. It functions in the clearance of misfolded proteins and damaged organelles, as well as recycling of cytosolic components during starvation to compensate for nutrient deprivation. This process is regulated by mTOR (mammalian target of rapamycin)-dependent and mTOR-independent pathways that are amenable to chemical perturbations. Several small molecules modulating autophagy have been identified that have potential therapeutic application in diverse human diseases, including neurodegeneration. Neurodegeneration-associated aggregation-prone proteins are predominantly degraded by autophagy and therefore stimulating this process with chemical inducers is beneficial in a wide range of transgenic disease models. Emerging evidence indicates that compromised autophagy contributes to the aetiology of various neurodegenerative diseases related to protein conformational disorders by causing the accumulation of mutant proteins and cellular toxicity. Combining the knowledge of autophagy dysfunction and the mechanism of drug action may thus be rational for designing targeted therapy. The present review describes the cellular signalling pathways regulating mammalian autophagy and highlights the potential therapeutic application of autophagy inducers in neurodegenerative disorders.
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Hale AN, Ledbetter DJ, Gawriluk TR, Rucker EB. Autophagy: regulation and role in development. Autophagy 2014; 9:951-72. [PMID: 24121596 DOI: 10.4161/auto.24273] [Citation(s) in RCA: 252] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Autophagy is an evolutionarily conserved cellular process through which long-lived proteins and damaged organelles are recycled to maintain energy homeostasis. These proteins and organelles are sequestered into a double-membrane structure, or autophagosome, which subsequently fuses with a lysosome in order to degrade the cargo. Although originally classified as a type of programmed cell death, autophagy is more widely viewed as a basic cell survival mechanism to combat environmental stressors. Autophagy genes were initially identified in yeast and were found to be necessary to circumvent nutrient stress and starvation. Subsequent elucidation of mammalian gene counterparts has highlighted the importance of this process to normal development. This review provides an overview of autophagy, the types of autophagy, its regulation and its known impact on development gleaned primarily from murine models.
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Affiliation(s)
- Amber N Hale
- Department of Biology; University of Kentucky; Lexington, KY USA
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16
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Shtein L, Toker L, Bersudsky Y, Belmaker RH, Agam G. The inositol monophosphatase inhibitor L-690,330 affects pilocarpine-behavior and the forced swim test. Psychopharmacology (Berl) 2013; 227:503-8. [PMID: 23344554 DOI: 10.1007/s00213-013-2969-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 01/04/2013] [Indexed: 11/25/2022]
Abstract
RATIONALE Lithium has been a standard pharmacological treatment for bipolar disorder over the last 60 years; however, the molecular targets through which lithium exerts its therapeutic effects are still not defined. Attenuation of the phosphatidylinositol signal transduction pathway as a consequence of inhibition of inositol monophosphatase (IMPase) has been proposed as one of the possible mechanisms for lithium-induced mood stabilization. OBJECTIVES The objective was to study the behavioral effect of the specific competitive IMPase inhibitor L-690,330 in mice in the lithium-sensitive pilocarpine-induced seizures paradigm and the forced swim test (FST). METHODS The inhibitor was administered intracerebroventricularly in liposomes. RESULTS L-690,330 increased the sensitivity to subconvulsive doses of pilocarpine and decreased immobility time in the FST. CONCLUSIONS It is possible that the behavioral effects of lithium in the pilocarpine-induced seizures and in the FST are mediated through the inhibition of IMPase, but reversal of the inhibitor's effect with intracerebroventricular inositol would be an important further step in proof.
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Affiliation(s)
- Liza Shtein
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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17
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Yang YP, Hu LF, Zheng HF, Mao CJ, Hu WD, Xiong KP, Wang F, Liu CF. Application and interpretation of current autophagy inhibitors and activators. Acta Pharmacol Sin 2013; 34:625-35. [PMID: 23524572 DOI: 10.1038/aps.2013.5] [Citation(s) in RCA: 278] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Autophagy is the major intracellular degradation system, by which cytoplasmic materials are delivered to and degraded in the lysosome. As a quality control mechanism for cytoplasmic proteins and organelles, autophagy plays important roles in a variety of human diseases, including neurodegenerative diseases, cancer, cardiovascular disease, diabetes and infectious and inflammatory diseases. The discovery of ATG genes and the dissection of the signaling pathways involved in regulating autophagy have greatly enriched our knowledge on the occurrence and development of this lysosomal degradation pathway. In addition to its role in degradation, autophagy may also promote a type of programmed cell death that is different from apoptosis, termed type II programmed cell death. Owing to the dual roles of autophagy in cell death and the specificity of diseases, the exact mechanisms of autophagy in various diseases require more investigation. The application of autophagy inhibitors and activators will help us understand the regulation of autophagy in human diseases, and provide insight into the use of autophagy-targeted drugs. In this review, we summarize the latest research on autophagy inhibitors and activators and discuss the possibility of their application in human disease therapy.
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18
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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] [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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19
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Mayati A, Levoin N, Paris H, N'Diaye M, Courtois A, Uriac P, Lagadic-Gossmann D, Fardel O, Le Ferrec E. Induction of intracellular calcium concentration by environmental benzo(a)pyrene involves a β2-adrenergic receptor/adenylyl cyclase/Epac-1/inositol 1,4,5-trisphosphate pathway in endothelial cells. J Biol Chem 2011; 287:4041-52. [PMID: 22167199 DOI: 10.1074/jbc.m111.319970] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (B(a)P) are widely distributed environmental contaminants, known as potent ligands of the aryl hydrocarbon receptor (AhR). These chemicals trigger an early and transient increase of intracellular calcium concentration ([Ca(2+)](i)), required for AhR-related effects of PAHs. The mechanisms involved in this calcium mobilization were investigated in the present study. We demonstrated that B(a)P-mediated [Ca(2+)](i) induction was prevented in endothelial HMEC-1 cells by counteracting β2-adrenoreceptor (β2ADR) activity using pharmacological antagonists, anti-β2ADR antibodies, or siRNA-mediated knockdown of β2ADR expression; by contrast, it was strongly potentiated by β2ADR overexpression in human kidney HEK293 cells. B(a)P was shown, moreover, to directly bind to β2ADR, as assessed by in vitro binding assays and molecular modeling. Pharmacological inhibition and/or siRNA-mediated silencing of various signaling actors acting downstream of β2ADR in a sequential manner, such as G protein, adenylyl cyclase, Epac-1 protein, and inositol 1,4,5-trisphosphate (IP(3))/IP(3) receptor, were next demonstrated to prevent B(a)P-induced calcium signal. Inhibition or knockdown of these signaling elements, as well as the use of chemical β-blockers, were finally shown to counteract B(a)P-mediated induction of cytochrome P-450 1B1, a prototypical AhR target gene. Taken together, our results show that B(a)P binds directly to β2ADR and consequently utilizes β2ADR machinery to mobilize [Ca(2+)](i), through activation of a G protein/adenylyl cyclase/cAMP/Epac-1/IP(3) pathway. This β2ADR-dependent signaling pathway activated by PAHs may likely be crucial for PAH-mediated up-regulation of AhR target genes, thus suggesting a contribution of β2ADR to the health-threatening effects of these environmental pollutants.
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Affiliation(s)
- Abdullah Mayati
- INSERM U1085/IRSET, IFR140, Université de Rennes 1, 2 Avenue du Pr. L. Bernard, Rennes 35043, France
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20
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Sorting nexin 3, a protein upregulated by lithium, contains a novel phosphatidylinositol-binding sequence and mediates neurite outgrowth in N1E-115 cells. Cell Signal 2009; 21:1586-94. [DOI: 10.1016/j.cellsig.2009.06.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 06/22/2009] [Accepted: 06/23/2009] [Indexed: 11/19/2022]
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21
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Di Daniel E, Mok MHS, Mead E, Mutinelli C, Zambello E, Caberlotto LL, Pell TJ, Langmead CJ, Shah AJ, Duddy G, Kew JNC, Maycox PR. Evaluation of expression and function of the H+/myo-inositol transporter HMIT. BMC Cell Biol 2009; 10:54. [PMID: 19607714 PMCID: PMC2717050 DOI: 10.1186/1471-2121-10-54] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 07/16/2009] [Indexed: 11/24/2022] Open
Abstract
Background The phosphoinositide (PIns) signalling pathway regulates a series of neuronal processes, such as neurotransmitter release, that are thought to be altered in mood disorders. Furthermore, mood-stabilising drugs have been shown to inhibit key enzymes that regulate PIns production and alter neuronal growth cone morphology in an inositol-reversible manner. Here, we describe analyses of expression and function of the recently identified H+/myo-inositol transporter (HMIT) investigated as a potential regulator of PIns signalling. Results We show that HMIT is primarily a neuronal transporter widely expressed in the rat and human brain, with particularly high levels in the hippocampus and cortex, as shown by immunohistochemistry. The transporter is localised at the Golgi apparatus in primary cultured neurones. No HMIT-mediated electrophysiological responses were detected in rat brain neurones or slices; in addition, inositol transport and homeostasis were unaffected in HMIT targeted null-mutant mice. Conclusion Together, these data do not support a role for HMIT as a neuronal plasma membrane inositol transporter, as previously proposed. However, we observed that HMIT can transport inositol triphosphate, indicating unanticipated intracellular functions for this transporter that may be relevant to mood control.
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Affiliation(s)
- Elena Di Daniel
- Psychiatry Discovery Technology Group, GlaxoSmithKline, New Frontiers Science Park, Harlow, UK.
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22
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Yan Z, Zhao J, Peng P, Chihara RK, Li J. BIN2 functions redundantly with other Arabidopsis GSK3-like kinases to regulate brassinosteroid signaling. PLANT PHYSIOLOGY 2009; 150:710-21. [PMID: 19395409 PMCID: PMC2689954 DOI: 10.1104/pp.109.138099] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 04/20/2009] [Indexed: 05/18/2023]
Abstract
GLYCOGEN SYNTHASE KINASE3 (GSK3) is a highly conserved serine/threonine kinase involved in a variety of developmental signaling processes. The Arabidopsis (Arabidopsis thaliana) genome encodes 10 GSK3-like kinases that are clustered into four groups. Forward genetic screens have so far uncovered eight mutants, all of which carry gain-of-function mutations in BRASSINOSTEROID-INSENSITIVE2 (BIN2), one of the three members in group II. Genetic and biochemical studies have implicated a negative regulatory role for BIN2 in brassinosteroid (BR) signaling. Here, we report the identification of eight ethyl methanesulfonate-mutagenized loss-of-function bin2 alleles and one T-DNA insertional mutation each for BIN2 and its two closest homologs, BIN2-Like1 and BIN2-Like2. Our genetic, biochemical, and physiological assays revealed that despite functional redundancy, BIN2 plays a dominant role among the three group II members in regulating BR signaling. Surprisingly, the bin2bil1bil2 triple T-DNA insertional mutant still responds to BR and accumulates a more phosphorylated form of a BIN2 substrate than the wild-type plant. Using the specific GSK3 inhibitor lithium chloride, we have provided strong circumstantial evidence for the involvement of other Arabidopsis GSK3-like kinases in BR signaling. Interestingly, lithium chloride treatment was able to suppress the gain-of-function bin2-1 mutation but had a much weaker effect on a strong BR receptor mutant, suggesting the presence of a BIN2-independent regulatory step downstream of BR receptor activation.
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Affiliation(s)
- Zhenyan Yan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1048, USA
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23
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Nowicki MO, Dmitrieva N, Stein AM, Cutter JL, Godlewski J, Saeki Y, Nita M, Berens ME, Sander LM, Newton HB, Chiocca EA, Lawler S. Lithium inhibits invasion of glioma cells; possible involvement of glycogen synthase kinase-3. Neuro Oncol 2008; 10:690-9. [PMID: 18715951 DOI: 10.1215/15228517-2008-041] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Therapies targeting glioma cells that diffusely infiltrate normal brain are highly sought after. Our aim was to identify novel approaches to this problem using glioma spheroid migration assays. Lithium, a currently approved drug for the treatment of bipolar illnesses, has not been previously examined in the context of glioma migration. We found that lithium treatment potently blocked glioma cell migration in spheroid, wound-healing, and brain slice assays. The effects observed were dose dependent and reversible, and worked using every glioma cell line tested. In addition, there was little effect on cell viability at lithium concentrations that inhibit migration, showing that this is a specific effect. Lithium treatment was associated with a marked change in cell morphology, with cells retracting the long extensions at their leading edge. Examination of known targets of lithium showed that inositol monophosphatase inhibition had no effect on glioma migration, whereas inhibition of glycogen synthase kinase-3 (GSK-3) did. This suggested that the effects of lithium on glioma cell migration could possibly be mediated through GSK-3. Specific pharmacologic GSK-3 inhibitors and siRNA knockdown of GSK-3alpha or GSK-3beta isoforms both reduced cell motility. These data outline previously unidentified pathways and inhibitors that may be useful for the development of novel anti-invasive therapeutics for the treatment of brain tumors.
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Affiliation(s)
- Michal O Nowicki
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center, Columbus, OH 43210, USA
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Sarkar S, Rubinsztein DC. Small molecule enhancers of autophagy for neurodegenerative diseases. MOLECULAR BIOSYSTEMS 2008; 4:895-901. [PMID: 18704227 DOI: 10.1039/b804606a] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, prion diseases and polyglutamine disorders, including Huntington's disease and various spinocerebellar ataxias, are associated with the formation of protein aggregates. These aggregates and/or their precursors are thought to be toxic disease-causing species. Autophagy is a major degradation pathway for intracytosolic aggregate-prone proteins, including those associated with neurodegeneration. It is a constitutive self-degradative process involved both in the basal turnover of cellular components and in response to nutrient starvation in eukaryotes. Enhancing autophagy may be a possible therapeutic strategy for neurodegenerative disorders where the mutant proteins are autophagy substrates. In cell and animal models, chemical induction of autophagy protects against the toxic insults of these mutant aggregate-prone proteins by enhancing their clearance. We will discuss various autophagy-inducing small molecules that have emerged in the past few years that may be leads towards the treatment of such devastating diseases.
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Affiliation(s)
- Sovan Sarkar
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Hills Road, Cambridge, UK.
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25
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Bachmann RF, Schloesser RJ, Gould TD, Manji HK. Mood stabilizers target cellular plasticity and resilience cascades: implications for the development of novel therapeutics. Mol Neurobiol 2007; 32:173-202. [PMID: 16215281 DOI: 10.1385/mn:32:2:173] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bipolar disorder is a devastating disease with a lifetime incidence of about 1% in the general population. Suicide is the cause of death in 10 to 15% of patients and in addition to suicide, mood disorders are associated with many other harmful health effects. Mood stabilizers are medications used to treat bipolar disorder. In addition to their therapeutic effects for the treatment of acute manic episodes, mood stabilizers are useful as prophylaxis against future episodes and as adjunctive antidepressant medications. The most established and investigated mood-stabilizing drugs are lithium and valproate but other anticonvulsants (such as carbamazepine and lamotrigine) and antipsychotics are also considered as mood stabilizers. Despite the efficacy of these diverse medications, their mechanisms of action remain, to a great extent, unknown. Lithium's inhibition of some enzymes, such as inositol monophosphatase and glycogen synthase kinase-3, probably results in its mood-stabilizing effects. Valproate may share its anticonvulsant target with its mood-stabilizing target or may act through other mechanisms. It has been shown that lithium, valproate, and/or carbamazepine regulate numerous factors involved in cell survival pathways, including cyclic adenine monophospate response element-binding protein, brain-derived neurotrophic factor, bcl-2, and mitogen-activated protein kinases. These drugs have been suggested to have neurotrophic and neuroprotective properties that ameliorate impairments of cellular plasticity and resilience underlying the pathophysiology of mood disorders. This article also discusses approaches to develop novel treatments specifically for bipolar disorder.
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Affiliation(s)
- Rosilla F Bachmann
- Laboratory of Molecular Pathophysiology, National Institute of Mental Health, Bethesda, MD, USA
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26
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Gould TD. Targeting glycogen synthase kinase-3 as an approach to develop novel mood-stabilising medications. Expert Opin Ther Targets 2006; 10:377-92. [PMID: 16706678 DOI: 10.1517/14728222.10.3.377] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Historically, success in the pharmacological treatment of bipolar disorder has arisen either from serendipitous findings or from studies with drugs (antipsychotics and anticonvulsants) developed for other indications (schizophrenia and epilepsy, respectively). Lithium has been in widespread clinical use in the treatment of bipolar disorder for > 30 years. Development of lithium-mimetic compounds has the potential to result in a more specific medication, with fewer side effects and a less narrow dose range. However, novel medications based upon a known mechanism of action of this drug are yet to be developed. Increasing evidence suggests that a next-generation lithium compound may derive from knowledge of a direct target of lithium, glycogen synthase kinase-3 (GSK-3). GSK-3 is an intracellular enzyme implicated as a critical component in many neuronal signalling pathways. However, despite the large body of preclinical data discussed in this review, definitive validation of GSK-3 as therapeutically relevant target of lithium will require clinical trials with novel GSK-3 inhibitors. A number of recent reports suggest that it is possible to develop selective, small-molecule GSK-3 inhibitors.
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Affiliation(s)
- Todd D Gould
- Laboratory of Molecular Pathophysiology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-3711, USA.
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Sarkar S, Floto RA, Berger Z, Imarisio S, Cordenier A, Pasco M, Cook LJ, Rubinsztein DC. Lithium induces autophagy by inhibiting inositol monophosphatase. ACTA ACUST UNITED AC 2005; 170:1101-11. [PMID: 16186256 PMCID: PMC2171537 DOI: 10.1083/jcb.200504035] [Citation(s) in RCA: 743] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Macroautophagy is a key pathway for the clearance of aggregate-prone cytosolic proteins. Currently, the only suitable pharmacologic strategy for up-regulating autophagy in mammalian cells is to use rapamycin, which inhibits the mammalian target of rapamycin (mTOR), a negative regulator of autophagy. Here we describe a novel mTOR-independent pathway that regulates autophagy. We show that lithium induces autophagy, and thereby, enhances the clearance of autophagy substrates, like mutant huntingtin and α-synucleins. This effect is not mediated by glycogen synthase kinase 3β inhibition. The autophagy-enhancing properties of lithium were mediated by inhibition of inositol monophosphatase and led to free inositol depletion. This, in turn, decreased myo-inositol-1,4,5-triphosphate (IP3) levels. Our data suggest that the autophagy effect is mediated at the level of (or downstream of) lowered IP3, because it was abrogated by pharmacologic treatments that increased IP3. This novel pharmacologic strategy for autophagy induction is independent of mTOR, and may help treatment of neurodegenerative diseases, like Huntington's disease, where the toxic protein is an autophagy substrate.
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Affiliation(s)
- Sovan Sarkar
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge CB2 2XY, England, UK
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Gould TD, Quiroz JA, Singh J, Zarate CA, Manji HK. Emerging experimental therapeutics for bipolar disorder: insights from the molecular and cellular actions of current mood stabilizers. Mol Psychiatry 2004; 9:734-55. [PMID: 15136794 DOI: 10.1038/sj.mp.4001518] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bipolar disorder afflicts approximately 1-3% of both men and women, and is coincident with major economic, societal, medical, and interpersonal consequences. Current mediations used for its treatment are associated with variable rates of efficacy and often intolerable side effects. While preclinical and clinical knowledge in the neurosciences has expanded at a tremendous rate, recent years have seen no major breakthroughs in the development of novel types of treatment for bipolar disorder. We review here approaches to develop novel treatments specifically for bipolar disorder. Deliberate (ie not by serendipity) treatments may come from one of two general mechanisms: (1) Understanding the mechanism of action of current medications and thereafter designing novel drugs that mimics these mechanism(s); (2) Basing medication development upon the hypothetical or proven underlying pathophysiology of bipolar disorder. In this review, we focus upon the first approach. Molecular and cellular targets of current mood stabilizers include lithium inhibitable enzymes where lithium competes for a magnesium binding site (inositol monophosphatase, inositol polyphosphate 1-phosphatase, glycogen synthase kinase-3 (GSK-3), fructose 1,6-bisphosphatase, bisphosphate nucleotidase, phosphoglucomutase), valproate inhibitable enzymes (succinate semialdehyde dehydrogenase, succinate semialdehyde reductase, histone deacetylase), targets of carbamazepine (sodium channels, adenosine receptors, adenylate cyclase), and signaling pathways regulated by multiple drugs of different classes (phosphoinositol/protein kinase C, cyclic AMP, arachidonic acid, neurotrophic pathways). While the task of developing novel medications for bipolar disorder is truly daunting, we are hopeful that understanding the mechanism of action of current mood stabilizers will ultimately lead clinical trials with more specific medications and thus better treatments those who suffer from this devastating illness.
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Affiliation(s)
- T D Gould
- Laboratory of Molecular Pathophysiology, National Institute of Mental Health, Bethesda, MD 20892, USA
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Abstract
Lithium is an effective drug for both the treatment and prophylaxis of bipolar disorder. However, the precise mechanism of lithium action is not yet well understood. Extensive research aiming to elucidate the molecular mechanisms underlying the therapeutic effects of lithium has revealed several possible targets. The behavioral and physiological manifestations of the illness are complex and are mediated by a network of interconnected neurotransmitter pathways. Thus, lithium's ability to modulate the release of serotonin at presynaptic sites and modulate receptor-mediated supersensitivity in the brain remains a relevant line of investigation. However, it is at the molecular level that some of the most exciting advances in the understanding of the long-term therapeutic action of lithium will continue in the coming years. The lithium cation possesses the selective ability, at clinically relevant concentrations, to alter the PI second-messenger system, potentially altering the activity and dynamic regulation of receptors that are coupled to this intracellular response. Subtypes of muscarinic receptors in the limbic system may represent particularly sensitive targets in this regard. Likewise, preclinical data have shown that lithium regulates arachidonic acid and the protein kinase C signaling cascades. It also indirectly regulates a number of factors involved in cell survival pathways, including cAMP response element binding protein, brain-derived neurotrophic factor, bcl-2 and mitogen-activated protein kinases, and may thus bring about delayed long-term beneficial effects via under-appreciated neurotrophic effects. Identification of the molecular targets for lithium in the brain could lead to the elucidation of the pathophysiology of bipolar disorder and the discovery of a new generation of mood stabilizers, which in turn may lead to improvements in the long-term outcome of this devastating illness (1).
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Affiliation(s)
- B Corbella
- 1Clinical Institute of Psychiatry and Psychology, University of Barcelona, Barcelona, Spain
| | - E Vieta
- 1Clinical Institute of Psychiatry and Psychology, University of Barcelona, Barcelona, Spain
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Pardo R, Andreolotti AG, Ramos B, Picatoste F, Claro E. Opposed effects of lithium on the MEK-ERK pathway in neural cells: inhibition in astrocytes and stimulation in neurons by GSK3 independent mechanisms. J Neurochem 2003; 87:417-26. [PMID: 14511119 DOI: 10.1046/j.1471-4159.2003.02015.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Lithium is widely used in the treatment of bipolar disorder, but despite its proven therapeutic efficacy, the molecular mechanisms of action are not fully understood. The present study was undertaken to explore lithium effects of the MEK/ERK cascade of protein kinases in astrocytes and neurons. In asynchronously proliferating rat cortical astrocytes, lithium decreased time- and dose-dependently the phosphorylation of MEK and ERK, with 1 mM concentrations achieving 60 and 50% inhibition of ERK and MEK, respectively, after a 7-day exposure. Lithium also inhibited [3H]thymidine incorporation into DNA and induced a G2/M cell cycle arrest. In serum-deprived, quiescent astrocytes, pre-exposure to lithium resulted in the inhibition of cell cycle re-entry as stimulated by the mitogen endothelin-1: under this experimental setting, lithium did not affect the rapid, peak phosphorylation of MEK taking place after 3-5 min, but was effective in inhibiting the long-term, sustained phosphorylation of MEK. Lithium inhibition of the astrocyte MEK/ERK pathway was independent of inositol depletion. Further, compound SB216763 inhibited Tau phosphorylation at Ser396 and stabilized cytosolic beta-catenin, consistent with the inhibition of glycogen synthase kinase-3 beta (GSK-3 beta), but failed to reproduce lithium effects on MEK and ERK phosphorylation and cell cycle arrest. In cerebellar granule neurons, millimolar concentrations of lithium enhanced MEK and ERK phosphorylation in a concentration-dependent manner, again through an inositol and GSK-3 beta independent mechanism. These opposing effects in astrocytes and neurons make lithium treatment a promising strategy to favour neural repair and reduce reactive gliosis after traumatic injury.
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Affiliation(s)
- Raúl Pardo
- Institut de Neurosciènces and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain
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31
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Westfall TA, Brimeyer R, Twedt J, Gladon J, Olberding A, Furutani-Seiki M, Slusarski DC. Wnt-5/pipetail functions in vertebrate axis formation as a negative regulator of Wnt/beta-catenin activity. J Cell Biol 2003; 162:889-98. [PMID: 12952939 PMCID: PMC2172822 DOI: 10.1083/jcb.200303107] [Citation(s) in RCA: 205] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2003] [Accepted: 07/02/2003] [Indexed: 11/22/2022] Open
Abstract
We provide genetic evidence defining a role for noncanonical Wnt function in vertebrate axis formation. In zebrafish, misexpression of Wnt-4, -5, and -11 stimulates calcium (Ca2+) release, defining the Wnt/Ca2+ class. We describe genetic interaction between two Wnt/Ca2+ members, Wnt-5 (pipetail) and Wnt-11 (silberblick), and a reduction of Ca2+ release in Wnt-5/pipetail. Embryos genetically depleted of both maternal and zygotic Wnt-5 product exhibit cell movement defects as well as hyperdorsalization and axis-duplication phenotypes. The dorsalized phenotypes result from increased beta-catenin accumulation and activation of downstream genes. The Wnt-5 loss-of-function defect is consistent with Ca2+ modulation having an antagonistic interaction with Wnt/beta-catenin signaling.
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Affiliation(s)
- Trudi A Westfall
- Department of Biological Sciences, University of Iowa, Iowa City, IA 52242, USA
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32
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Westfall TA, Hjertos B, Slusarski DC. Requirement for intracellular calcium modulation in zebrafish dorsal-ventral patterning. Dev Biol 2003; 259:380-91. [PMID: 12871708 DOI: 10.1016/s0012-1606(03)00209-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The phosphoinositide (PI) cycle is an important signal transduction pathway that, upon activation, generates intracellular second messengers and leads to calcium release. To determine whether PI cycle-mediated intracellular calcium release is required for body plan formation, we systematically dissect PI cycle function in the zebrafish (Danio rerio). We inhibit PI cycle function at three different steps and deplete internal calcium stores, demonstrating an impact on endogenous calcium release and Wnt/beta-catenin signaling. Inhibition of endogenous calcium modulation induces hyperdorsalized phenotypes in a dose-dependent manner. Ectopic dorsal-signaling centers are generated in PI cycle-inhibited embryos as demonstrated by altered beta-catenin subcellular localization and ectopic expression of beta-catenin target genes. These results provide evidence that modulation of calcium release is critical for early embryonic patterning and acts by influencing the stabilization of beta-catenin protein.
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Affiliation(s)
- Trudi A Westfall
- Department of Biological Sciences, University of Iowa, Iowa City, IA 52242, USA
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33
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Abstract
Bioactivatable protecting groups represent an enormously powerful tool to increase bioavailability or to generally help deliver drugs to cells. This approach is particularly valuable in the case of biologically active phosphates because of the high intrinsic hydrophilicity and the multitude of biological functions phosphate esters exhibit inside cells. Here, the most prominent masking groups used so far are introduced. The stability and toxicology of the resulting prodrugs is discussed. Finally, this review tries to cover briefly some of the work that describes the usefulness and efficiency of the approach in various application areas.
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Affiliation(s)
- Carsten Schultz
- European Molecular Biology Laboratory, Meyerhofstr. 1, 69117, Heidelberg, Germany.
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34
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Wang X, Liu XT, Dunn R, Ohl DA, Smith GD. Glycogen synthase kinase-3 regulates mouse oocyte homologue segregation. Mol Reprod Dev 2003; 64:96-105. [PMID: 12420304 DOI: 10.1002/mrd.10213] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Intracellular regulation of oocyte meiosis is not completely understood. However, reversible phosphorylation, which involves serine/threonine protein kinases and phosphatases (PP), is an important mediator. Glycogen synthase kinase-3 (GSK-3) is a highly conserved serine/threonine protein kinase. Currently no reports exist on presence or function of GSK-3 in mammalian oocytes. The aim of this study was to determine GSK-3 presence/absence, transcript and protein expression, intracellular protein distribution, and to investigate the functional importance of GSK-3 in mouse oocyte meiosis. Germinal vesicle-intact (GVI) oocytes contained both GSK-3 transcript and protein. Although GSK-3 beta-isoform is the only transcript identifiable in GVI oocytes, both alpha- and beta-isoforms were recognized by Western blot analysis. In growing, meiotic-incompetent oocytes GSK-3 was present, diffusely located throughout the cytoplasm and absent in the nucleus, whereas in meiotic-competent oocytes this cytoplasmic GSK-3 displays a predominant peri-oolemma staining. Treatment of mouse GVI oocytes with lithium chloride (LiCl), which inhibits both inositol monophosphatase (IMPase) and GSK-3, had no significant influence on oocyte viability, morphology, or development to metaphase II (MII). However, LiCl caused abnormal spindle formation and significantly increased incidence of abnormal homologue segregation during the first meiotic division. L690,330, which is a specific IMPase inhibitor, had no significant effect on oocyte viability, morphology, MII development, or homologue segregation. This is the first report of GSK-3 in mammalian oocytes. LiCl inhibition of mouse oocyte GSK-3 modified organization of microtubules and/or function of meiotic spindles thus compromising segregation of condensed bivalent chromosomes.
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Affiliation(s)
- Xia Wang
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan, USA
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35
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Sun X, Sato S, Murayama O, Murayama M, Park JM, Yamaguchi H, Takashima A. Lithium inhibits amyloid secretion in COS7 cells transfected with amyloid precursor protein C100. Neurosci Lett 2002; 321:61-4. [PMID: 11872257 DOI: 10.1016/s0304-3940(01)02583-6] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To examine the regulation of amyloid secretion in more detail, Abeta sandwich ELISAs with high sensitivity and specificity were developed. Using this technique, we measured Abeta secreted from COS7 cells transiently transfected with APP C100 in the presence of LiCl, a potent glycogen synthase kinase (GSK)-3beta inhibitor. We found that both Abetax-40 and Abetax-42 secretion were reduced by LiCl treatment in a dose-dependent manner. Diminished amyloid secretion was associated with GSK-3beta activity. These results suggest that GSK-3beta might function as a possible mediator for regulating both amyloid deposition and tau pathology in Alzheimer's disease (AD), and that lithium should be re-evaluated as a candidate reagent for preventing AD pathology.
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Affiliation(s)
- X Sun
- Lab for Alzheimer's Disease, The Brain Science Institute of RIKEN, 2-1 Hirosawa, Wako, 351-0198 Saitama, Japan
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36
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Ali A, Hoeflich KP, Woodgett JR. Glycogen synthase kinase-3: properties, functions, and regulation. Chem Rev 2001; 101:2527-40. [PMID: 11749387 DOI: 10.1021/cr000110o] [Citation(s) in RCA: 297] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A Ali
- Division of Experimental Therapeutics, Ontario Cancer Institute, 610-University Avenue, Toronto, Ontario, Canada M5G 2M9.
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37
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Abstract
Lithium is highly effective in the treatment of bipolar disorder and also has multiple effects on embryonic development, glycogen synthesis, hematopoiesis, and other processes. However, the mechanism of lithium action is still unclear. A number of enzymes have been proposed as potential targets of lithium action, including inositol monophosphatase, a family of structurally related phosphomonoesterases, and the protein kinase glycogen synthase kinase-3. These potential targets are widely expressed, require metal ions for catalysis, and are generally inhibited by lithium in an uncompetitive manner, most likely by displacing a divalent cation. Thus, the challenge is to determine which target, if any, is responsible for a given response to lithium in cells. Comparison of lithium effects with genetic disruption of putative target molecules has helped to validate these targets, and the use of alternative inhibitors of a given target can also lend strong support for or against a proposed mechanism of lithium action. In this review, lithium sensitive enzymes are discussed, and a number of criteria are proposed to evaluate which of these enzymes are involved in the response to lithium in a given setting.
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Affiliation(s)
- C J Phiel
- Department of Medicine and Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104. USA.
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38
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Abstract
Inositol monophosphatase (IMPase) catalyses the hydrolysis of myo-inositol monophosphates to myo-inositol, which is required in the phosphatidyl inositol cell signalling pathway. Here the enzyme structure, mechanism and inhibition of IMPase are reviewed. Lithium, an effective therapy for manic depression, is an uncompetitive inhibitor. In the search for alternative inhibitors to lithium, substrate-based inhibitors, bisphosphonates, terpenoid and tropolone analogues are described.
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Affiliation(s)
- C M Fauroux
- School of Pharmacy and Pharmaceutical Sciences, University of Manchester, UK
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39
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Chalecka-Franaszek E, Chuang DM. Lithium activates the serine/threonine kinase Akt-1 and suppresses glutamate-induced inhibition of Akt-1 activity in neurons. Proc Natl Acad Sci U S A 1999; 96:8745-50. [PMID: 10411946 PMCID: PMC17587 DOI: 10.1073/pnas.96.15.8745] [Citation(s) in RCA: 416] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This report describes a modulatory action of lithium and glutamate on the activity of serine/threonine kinase Akt-1. Lithium is most commonly used to treat bipolar disorder, but the mechanism of its therapeutic action remains unknown. We have recently demonstrated that lithium protects against glutamate-induced excitotoxicity in cultured brain neurons and in an animal model of cerebral ischemia. This study was undertaken to investigate the role of Akt-1, activated by the phosphatidylinositol 3-kinase (PI 3-K) signaling pathway, in mediating glutamate excitotoxicity and lithium protection in cerebellar granule cells. High levels of phosphorylation and activity of Akt-1 were detected in cerebellar neurons cultured in the presence of serum. Protracted treatment with selective PI 3-K inhibitors, wortmannin and LY294002, abolished Akt-1 activity and induced neuronal death that could be reduced by long-term lithium pretreatment. Exposure of cells to glutamate induced a rapid and reversible loss of Akt-1 phosphorylation and kinase activity. These effects were closely correlated with excitotoxicity and caspase 3 activation and were prevented by phosphatase inhibitors, okadaic acid and caliculin A. Long-term lithium pretreatment suppressed glutamate-induced loss of Akt-1 activity and accelerated its recovery toward the control levels. Lithium treatment alone induced rapid increase in PI 3-K activity, and Akt-1 phosphorylation with accompanying kinase activation, which was blocked by PI 3-K inhibitors. Lithium also increased the phosphorylation of glycogen synthase kinase-3 (GSK-3), a downstream physiological target of Akt. Thus, modulation of Akt-1 activity appears to play a key role in the mechanism of glutamate excitotoxicity and lithium neuroprotection.
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Affiliation(s)
- E Chalecka-Franaszek
- Section on Molecular Neurobiology, Biological Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1272, USA
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40
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Ganzhorn AJ, Hoflack J, Pelton PD, Strasser F, Chanal MC, Piettre SR. Inhibition of myo-inositol monophosphatase isoforms by aromatic phosphonates. Bioorg Med Chem 1998; 6:1865-74. [PMID: 9839016 DOI: 10.1016/s0968-0896(98)00148-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
alpha-Hydroxyphosphonates are moderately potent (Ki = 6-600 microM) inhibitors of the enzyme myo-inositol monophosphatase (McLeod et al., Med. Chem. Res. 1992, 2, 96). Hydroxy-[4-(5,6,7,8-tetrahydronaphtyl-1-oxy)phenyl]methyl phosphonate (3) was resynthesized and its inhibitory potency towards the recombinant bovine brain enzyme confirmed (Ki = 20 microM). Similar aromatic difluoro-, keto-, and ketodifluorophosphonates (5, 7, 9) were inactive. Compound 3 was 15-fold less active on the human as compared to the bovine enzyme. Molecular modeling suggested that the hydrophobic part of the inhibitor interacts with amino acid side chains that are located at the interface between the enzyme subunits in an area (amino acids 175-185) with low similarity between the two isozymes. Phe-183 in the human enzyme was replaced with leucine, the corresponding residue in the bovine isoform. The three isozymes (human wild-type, bovine wild-type and human F183L) had similar kinetic properties, except that the bovine enzyme was less effectively inhibited by high concentrations of the activator Mg2+. The F183L mutant enzyme had a twofold increased affinity for compound 3 as compared to the human wild-type form. We conclude that residue 183 contributes to the binding of aromatic hydroxyphosphonates to IMPase, but it is not the only determining factor for inhibitor specificity with respect to different isozymes.
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Affiliation(s)
- A J Ganzhorn
- Marion Merrell Research Institute, Strasbourg, France
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41
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Nonaka S, Hough CJ, Chuang DM. Chronic lithium treatment robustly protects neurons in the central nervous system against excitotoxicity by inhibiting N-methyl-D-aspartate receptor-mediated calcium influx. Proc Natl Acad Sci U S A 1998; 95:2642-7. [PMID: 9482940 PMCID: PMC19446 DOI: 10.1073/pnas.95.5.2642] [Citation(s) in RCA: 339] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Lithium is the most commonly used drug for the treatment of manic depressive illness. The precise mechanisms underlying its clinical efficacy remain unknown. We found that long-term exposure to lithium chloride dramatically protects cultured rat cerebellar, cerebral cortical, and hippocampal neurons against glutamate-induced excitotoxicity, which involves apoptosis mediated by N-methyl-D-aspartate (NMDA) receptors. This neuroprotection is long-lasting, occurs at therapeutically relevant concentrations of lithium with an EC50 of approximately 1.3 mM, and requires treatment for 6-7 days for complete protection to occur. In contrast, a 24-h treatment with lithium is ineffective. The protection in cerebellar neurons is specific for glutamate-induced excitotoxicity and can be attributed to inhibition of NMDA receptor-mediated calcium influx measured by 45Ca2+ uptake studies and fura-2 fluorescence microphotometry. The long-term effects of lithium are not caused by down-regulation of NMDA receptor subunit proteins and are unlikely related to its known ability to block inositol monophosphatase activity. Our results suggest that modulation of glutamate receptor hyperactivity represents at least part of the molecular mechanisms by which lithium alters brain function and exerts its clinical efficacy in the treatment for manic depressive illness. These actions of lithium also suggest that abnormality of glutamatergic neurotransmission as a pathogenic mechanism underlying bipolar illness warrants future investigation.
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Affiliation(s)
- S Nonaka
- Section on Molecular Neurobiology, Biological Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, MSC 1272, Bethesda, MD 20892-1272, USA
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42
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Piettre SR, André C, Chanal MC, Ducep JB, Lesur B, Piriou F, Raboisson P, Rondeau JM, Schelcher C, Zimmermann P, Ganzhorn AJ. Monoaryl- and bisaryldihydroxytropolones as potent inhibitors of inositol monophosphatase. J Med Chem 1997; 40:4208-21. [PMID: 9435892 DOI: 10.1021/jm9701942] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The first successful preparation of mono- and disubstituted 3,7-dihydroxytropolone involves a four-step synthetic scheme. Thus, bromination of 3,7-dihydroxytropolone (8) followed by permethylation of the resultant products furnished gram quantities of intermediates 13-18. Single or double Suzuki coupling reactions between these permethylated monobromo- and dibromodihydroxytropolone derivatives and a variety of boronic acids delivered the expected products whose deprotection yielded the desired compounds 1a-u and 26a-n, usually in fair to good yields. Tropolones 1 and 26 were found to be potent inhibitors of inositol monophosphatase with IC50 values in the low-micromolar range. The results are discussed in the context of the recently described novel mode of inhibition of the enzyme by 3,7-dihydroxytropolones.
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Affiliation(s)
- S R Piettre
- Marion Merrell Research Institute, Strasbourg, France.
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43
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Kume S, Muto A, Inoue T, Suga K, Okano H, Mikoshiba K. Role of inositol 1,4,5-trisphosphate receptor in ventral signaling in Xenopus embryos. Science 1997; 278:1940-3. [PMID: 9395395 DOI: 10.1126/science.278.5345.1940] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The inositol 1,4,5-trisphosphate (IP3) receptor is a calcium ion channel involved in the release of free Ca2+ from intracellular stores. For analysis of the role of IP3-induced Ca2+ release (IICR) on patterning of the embryonic body, monoclonal antibodies that inhibit IICR were produced. Injection of these blocking antibodies into the ventral part of early Xenopus embryos induced modest dorsal differentiation. A close correlation between IICR blocking potencies and ectopic dorsal axis induction frequency suggests that an active IP3-Ca2+ signal may participate in the modulation of ventral differentiation.
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MESH Headings
- Activins
- Animals
- Antibodies, Blocking
- Antibodies, Monoclonal
- Body Patterning
- Calcium/metabolism
- Calcium Channels/immunology
- Calcium Channels/metabolism
- Cell Differentiation
- Embryo, Nonmammalian/metabolism
- Embryonic Development
- Embryonic Induction
- Fibroblast Growth Factor 2/pharmacology
- Gastrula/metabolism
- Gene Expression Regulation, Developmental
- Inhibins/pharmacology
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate Receptors
- Receptors, Cytoplasmic and Nuclear/immunology
- Receptors, Cytoplasmic and Nuclear/metabolism
- Signal Transduction
- Xenopus
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Affiliation(s)
- S Kume
- Mikoshiba Calciosignal Net Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST), 2-9-3 Shimo-Meguro, Meguro-ku, Tokyo 153, Japan.
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44
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Slusarski DC, Corces VG, Moon RT. Interaction of Wnt and a Frizzled homologue triggers G-protein-linked phosphatidylinositol signalling. Nature 1997; 390:410-3. [PMID: 9389482 DOI: 10.1038/37138] [Citation(s) in RCA: 498] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In Drosophila, members of the frizzled family of tissue-polarity genes encode proteins that are likely to function as cell-surface receptors of the type known as Wnt receptors, and to initiate signal transduction across the cell membrane, although how they do this is unclear. We show here that the rat protein Frizzled-2 causes an increase in the release of intracellular calcium which is enhanced by Xwnt-5a, a member of the Wnt family. This release of intracellular calcium is suppressed by an inhibitor of the enzyme inositol monophosphatase and hence of the phosphatidylinositol signalling pathway; this suppression can be rescued by injection of the compound myo-inositol, which overcomes the decrease in this intermediate caused by the inhibitor. Agents that inhibit specific G-protein subunits, pertussis toxin, GDP-beta-S and alpha-transducin also inhibit the calcium release triggered by Xwnt-5a and rat Frizzled-2. Our results indicate that some Wnt proteins work through specific Frizzled homologues to stimulate the phosphatidylinositol signalling pathway via heterotrimeric G-protein subunits.
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Affiliation(s)
- D C Slusarski
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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45
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Abstract
This review starts from the classical standpoint that there are at least two separable processes acting with respect to axis formation and tissue specification in the early Xenopus embryo: a UV-insensitive event establishing a postgastrula embryo consisting of three concentric germ layers, ectoderm, mesoderm and endoderm, all of a ventral character; and a UV-sensitive event producing tissue of a dorsal type, including somites, notochord and neural tissue, and concomitantly establishing the dorsoventral and anteroposterior axes. The experimental evidence suggesting the molecular basis of the dorsal and ventral pathways is reviewed.
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Affiliation(s)
- J Heasman
- Institute of Human Genetics and Department of Cell Biology and Neuroanatomy, University of Minnesota School of Medicine, Minneapolis 55455, USA.
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46
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Hong M, Chen DC, Klein PS, Lee VM. Lithium reduces tau phosphorylation by inhibition of glycogen synthase kinase-3. J Biol Chem 1997; 272:25326-32. [PMID: 9312151 DOI: 10.1074/jbc.272.40.25326] [Citation(s) in RCA: 345] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Lithium is one of the most widely used drugs for treating bipolar (manic-depressive) disorder. Despite its efficacy, the molecular mechanism underlying its action has not been elucidated. One recent study has proposed that lithium inhibits glycogen synthase kinase-3 and thereby affects multiple cellular functions. Because glycogen synthase kinase-3 regulates the phosphorylation of tau (microtubule-binding protein that forms paired helical filaments in neurons of the Alzheimer's disease brain), we hypothesized that lithium could affect tau phosphorylation by inhibiting glycogen synthase kinase-3. Using cultured human NT2N neurons, we demonstrate that lithium reduces the phosphorylation of tau, enhances the binding of tau to microtubules, and promotes microtubule assembly through direct and reversible inhibition of glycogen synthase kinase-3. These results provide new insights into how lithium mediates its effects in the central nervous system, and these findings could be exploited to develop a novel intervention for Alzheimer's disease.
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Affiliation(s)
- M Hong
- Department of Pharmacology, the Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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47
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Kume S, Muto A, Okano H, Mikoshiba K. Developmental expression of the inositol 1,4,5-trisphosphate receptor and localization of inositol 1,4,5-trisphosphate during early embryogenesis in Xenopus laevis. Mech Dev 1997; 66:157-68. [PMID: 9376319 DOI: 10.1016/s0925-4773(97)00101-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
To study the role of inositol 1,4,5-trisphosphate (IP3) receptors during early embryogenesis in Xenopus, we examined the temporal-spatial localization of Xenopus IP3 receptor (XIP3R). XIP3R protein is enriched in the animal hemisphere of early cleavage stage embryos and becomes localized in the ectoderm and involuted mesoderm in gastrula stage embryos. Up to tailbud stages, expression of XIP3R is observed in the mesodermal tissues and in most subregions of the central nervous system. A quantitative analysis of endogenous IP3 mass during normal early embryogenesis revealed an increase in IP3 mass first observed at early gastrula stage of 10.5 with an enrichment in the ectoderm throughout the gastrula stages, implying a potential role during gastrulation.
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Affiliation(s)
- S Kume
- Mikoshiba Calciosignal Net Project, Exploratory Research for Advanced Technology, Japan Science and Technology Corporation, Tokyo.
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48
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Murakami H, Takahashi N, Tanaka S, Nakamura I, Udagawa N, Nakajo S, Nakaya K, Abe M, Yuda Y, Konno F, Barbier A, Suda T. Tiludronate inhibits protein tyrosine phosphatase activity in osteoclasts. Bone 1997; 20:399-404. [PMID: 9145236 DOI: 10.1016/s8756-3282(97)00025-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Signaling pathways mediated by tyrosine phosphorylation and dephosphorylation have been reported to be involved in the regulation of cytoskeletal organization in osteoclasts, the principal cells responsible for bone resorption. We examined the effects of tiludronate [(4-chlorophenyl)thiomethylene bisphosphonate] on the cytoskeleton and the balance of phosphotyrosine levels in osteoclast-like multinucleated cells (OCLs) formed in cocultures of mouse osteoblastic cells and bone marrow cells. When OCLs were placed on plastic dishes in the presence of 10% fetal bovine serum, they formed a ringed structure of F-actin dots (actin ring) within 2 h. Tiludronate did not inhibit the process of actin ring formation, but it disrupted preformed actin rings in a time- and a dose-dependent manner. Western blot analysis using an antiphosphotyrosine antibody revealed that tyrosine phosphorylation of certain proteins in OCLs was stimulated by tiludronate added to the purified OCLs. Tyrosine kinase activity of the p60c-src immunoprecipitated from cell lysates of the purified OCLs was not affected by tiludronate directly added to the kinase assay. OCL lysates stimulated dephosphorylation of tyrosine-phosphorylated substrates such as phosphoneuroprotein 14 and epidermal growth factor receptors. Like sodium orthovanadate, an inhibitor of protein tyrosine phosphatases, tiludronate dose-dependently inhibited tyrosine dephosphorylation of those substrates induced by OCL lysates. These findings suggest that tiludronate disrupts the preformed actin rings and suppresses bone-resorbing activity by inhibiting protein tyrosine phosphatases in osteoclasts.
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Affiliation(s)
- H Murakami
- Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan
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49
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Hedgepeth CM, Conrad LJ, Zhang J, Huang HC, Lee VM, Klein PS. Activation of the Wnt signaling pathway: a molecular mechanism for lithium action. Dev Biol 1997; 185:82-91. [PMID: 9169052 DOI: 10.1006/dbio.1997.8552] [Citation(s) in RCA: 482] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Glycogen synthase kinase-3 beta (GSK-3 beta/zeste-white-3/shaggy) is a negative regulator of the wnt signaling pathway which plays a central role in the development of invertebrates and vertebrates; loss of function and dominant negative mutations in GSK-3 beta lead to activation of the wnt pathway in Drosophila and Xenopus. We now provide evidence that lithium activates downstream components of the wnt signaling pathway in vivo, leading to accumulation of beta-catenin protein. Our data indicate that this activation of the wnt pathway is a consequence of inhibition of GSK-3 beta by lithium. Using a novel assay for GSK-3 beta in oocytes, we show that lithium inhibits GSK-3 beta from species as diverse as Dictyostelium discoideum and Xenopus laevis, providing a biochemical mechanism for the action of lithium on the development of these organisms. Lithium treatment also leads to activation of an AP-1-luciferase reporter in Xenopus embryos, consistent with previous observations that GSK-3 beta inhibits c-jun activity. Activation of the wnt pathway with a dominant negative form of GSK-3 beta is inhibited by myo-inositol, similar to the previously described effect of coinjecting myo-inositol with lithium. The mechanism by which myo-inositol inhibits both dominant negative GSK-3 beta and lithium remains uncertain.
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Affiliation(s)
- C M Hedgepeth
- Cell and Molecular Biology Graduate Group, University of Pennsylvania School of Medicine, Philadelphia 19104-6148, USA
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Piettre SR, Ganzhorn A, Hoflack J, Islam K, Hornsperger JM. α-Hydroxytropolones: A New Class of Potent Inhibitors of Inositol Monophosphatase and Other Bimetallic Enzymes. J Am Chem Soc 1997. [DOI: 10.1021/ja9634278] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Serge R. Piettre
- Contribution from the Marion Merrell Research Institute (presently Synthélabo Biomoléculaire), 16 rue d'Ankara, F-67080-Strasbourg, France
| | - Axel Ganzhorn
- Contribution from the Marion Merrell Research Institute (presently Synthélabo Biomoléculaire), 16 rue d'Ankara, F-67080-Strasbourg, France
| | - Jan Hoflack
- Contribution from the Marion Merrell Research Institute (presently Synthélabo Biomoléculaire), 16 rue d'Ankara, F-67080-Strasbourg, France
| | - Khalid Islam
- Contribution from the Marion Merrell Research Institute (presently Synthélabo Biomoléculaire), 16 rue d'Ankara, F-67080-Strasbourg, France
| | - Jean-Marie Hornsperger
- Contribution from the Marion Merrell Research Institute (presently Synthélabo Biomoléculaire), 16 rue d'Ankara, F-67080-Strasbourg, France
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