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Larramona-Arcas R, González-Arias C, Perea G, Gutiérrez A, Vitorica J, García-Barrera T, Gómez-Ariza JL, Pascua-Maestro R, Ganfornina MD, Kara E, Hudry E, Martinez-Vicente M, Vila M, Galea E, Masgrau R. Sex-dependent calcium hyperactivity due to lysosomal-related dysfunction in astrocytes from APOE4 versus APOE3 gene targeted replacement mice. Mol Neurodegener 2020; 15:35. [PMID: 32517777 PMCID: PMC7285605 DOI: 10.1186/s13024-020-00382-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 05/25/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The apolipoprotein E (APOE) gene exists in three isoforms in humans: APOE2, APOE3 and APOE4. APOE4 causes structural and functional alterations in normal brains, and is the strongest genetic risk factor of the sporadic form of Alzheimer's disease (LOAD). Research on APOE4 has mainly focused on the neuronal damage caused by defective cholesterol transport and exacerbated amyloid-β and Tau pathology. The impact of APOE4 on non-neuronal cell functions has been overlooked. Astrocytes, the main producers of ApoE in the healthy brain, are building blocks of neural circuits, and Ca2+ signaling is the basis of their excitability. Because APOE4 modifies membrane-lipid composition, and lipids regulate Ca2+ channels, we determined whether APOE4 dysregulates Ca2+signaling in astrocytes. METHODS Ca2+ signals were recorded in astrocytes in hippocampal slices from APOE3 and APOE4 gene targeted replacement male and female mice using Ca2+ imaging. Mechanistic analyses were performed in immortalized astrocytes. Ca2+ fluxes were examined with pharmacological tools and Ca2+ probes. APOE3 and APOE4 expression was manipulated with GFP-APOE vectors and APOE siRNA. Lipidomics of lysosomal and whole-membranes were also performed. RESULTS We found potentiation of ATP-elicited Ca2+responses in APOE4 versus APOE3 astrocytes in male, but not female, mice. The immortalized astrocytes modeled the male response, and showed that Ca2+ hyperactivity associated with APOE4 is caused by dysregulation of Ca2+ handling in lysosomal-enriched acidic stores, and is reversed by the expression of APOE3, but not of APOE4, pointing to loss of function due to APOE4 malfunction. Moreover, immortalized APOE4 astrocytes are refractory to control of Ca2+ fluxes by extracellular lipids, and present distinct lipid composition in lysosomal and plasma membranes. CONCLUSIONS Immortalized APOE4 versus APOE3 astrocytes present: increased Ca2+ excitability due to lysosome dysregulation, altered membrane lipidomes and intracellular cholesterol distribution, and impaired modulation of Ca2+ responses upon changes in extracellular lipids. Ca2+ hyperactivity associated with APOE4 is found in astrocytes from male, but not female, targeted replacement mice. The study suggests that, independently of Aβ and Tau pathologies, altered astrocyte excitability might contribute to neural-circuit hyperactivity depending on APOE allele, sex and lipids, and supports lysosome-targeted therapies to rescue APOE4 phenotypes in LOAD.
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Affiliation(s)
- Raquel Larramona-Arcas
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, and, Institut de Neurociències (INc), Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Catalonia Spain
| | - Candela González-Arias
- Cajal Institute, Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain
| | - Gertrudis Perea
- Cajal Institute, Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain
| | - Antonia Gutiérrez
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Instituto de Investigación Biomedica de Málaga (IBIMA), Universidad de Málaga, 29071 Málaga, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
| | - Javier Vitorica
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Instituto de Biomedicina de Sevilla (IBiS)-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Sevilla, Spain
| | - Tamara García-Barrera
- Departamento de Química, Facultad de Ciencias Experimentales, Campus de El Carmen, Centro de Investigación en Recursos Naturales, Salud y Medio Ambiente (RENSMA), Universidad de Huelva, 21007 Huelva, Spain
| | - José Luis Gómez-Ariza
- Departamento de Química, Facultad de Ciencias Experimentales, Campus de El Carmen, Centro de Investigación en Recursos Naturales, Salud y Medio Ambiente (RENSMA), Universidad de Huelva, 21007 Huelva, Spain
| | - Raquel Pascua-Maestro
- Departamento de Bioquímica y Biología Molecular y Fisiología, Instituto de Biología y Genética Molecular, Universidad de Valladolid-CSIC, 43007 Valladolid, Spain
| | - María Dolores Ganfornina
- Departamento de Bioquímica y Biología Molecular y Fisiología, Instituto de Biología y Genética Molecular, Universidad de Valladolid-CSIC, 43007 Valladolid, Spain
| | - Eleanna Kara
- Alzheimer’s Disease Research Laboratory, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129 USA
- Present Address: Institute of Neuropathology, University Hospital of Zurich, 8091 Zurich, Switzerland
| | - Eloise Hudry
- Alzheimer’s Disease Research Laboratory, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129 USA
| | - Marta Martinez-Vicente
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
- Neurodegenerative Diseases Research Group, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain
| | - Miquel Vila
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, and, Institut de Neurociències (INc), Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Catalonia Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
- Neurodegenerative Diseases Research Group, Vall d’Hebron Research Institute (VHIR), 08035 Barcelona, Spain
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia Spain
| | - Elena Galea
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, and, Institut de Neurociències (INc), Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Catalonia Spain
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia Spain
| | - Roser Masgrau
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, and, Institut de Neurociències (INc), Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Catalonia Spain
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Kastanenka KV, Moreno-Bote R, De Pittà M, Perea G, Eraso-Pichot A, Masgrau R, Poskanzer KE, Galea E. A roadmap to integrate astrocytes into Systems Neuroscience. Glia 2020; 68:5-26. [PMID: 31058383 PMCID: PMC6832773 DOI: 10.1002/glia.23632] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/14/2022]
Abstract
Systems neuroscience is still mainly a neuronal field, despite the plethora of evidence supporting the fact that astrocytes modulate local neural circuits, networks, and complex behaviors. In this article, we sought to identify which types of studies are necessary to establish whether astrocytes, beyond their well-documented homeostatic and metabolic functions, perform computations implementing mathematical algorithms that sub-serve coding and higher-brain functions. First, we reviewed Systems-like studies that include astrocytes in order to identify computational operations that these cells may perform, using Ca2+ transients as their encoding language. The analysis suggests that astrocytes may carry out canonical computations in a time scale of subseconds to seconds in sensory processing, neuromodulation, brain state, memory formation, fear, and complex homeostatic reflexes. Next, we propose a list of actions to gain insight into the outstanding question of which variables are encoded by such computations. The application of statistical analyses based on machine learning, such as dimensionality reduction and decoding in the context of complex behaviors, combined with connectomics of astrocyte-neuronal circuits, is, in our view, fundamental undertakings. We also discuss technical and analytical approaches to study neuronal and astrocytic populations simultaneously, and the inclusion of astrocytes in advanced modeling of neural circuits, as well as in theories currently under exploration such as predictive coding and energy-efficient coding. Clarifying the relationship between astrocytic Ca2+ and brain coding may represent a leap forward toward novel approaches in the study of astrocytes in health and disease.
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Affiliation(s)
- Ksenia V. Kastanenka
- Department of Neurology, MassGeneral Institute for Neurodegenerative Diseases, Massachusetts General Hospital and Harvard Medical School, Massachusetts 02129, USA
| | - Rubén Moreno-Bote
- Department of Information and Communications Technologies, Center for Brain and Cognition and Universitat Pompeu Fabra, 08018 Barcelona, Spain
- ICREA, 08010 Barcelona, Spain
| | | | | | - Abel Eraso-Pichot
- Departament de Bioquímica, Institut de Neurociències i Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Roser Masgrau
- Departament de Bioquímica, Institut de Neurociències i Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Kira E. Poskanzer
- Department of Biochemistry & Biophysics, Neuroscience Graduate Program, and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, California 94143, USA
- Equally contributing authors
| | - Elena Galea
- ICREA, 08010 Barcelona, Spain
- Departament de Bioquímica, Institut de Neurociències i Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Equally contributing authors
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Riefolo F, Matera C, Garrido-Charles A, Gomila AMJ, Sortino R, Agnetta L, Claro E, Masgrau R, Holzgrabe U, Batlle M, Decker M, Guasch E, Gorostiza P. Optical Control of Cardiac Function with a Photoswitchable Muscarinic Agonist. J Am Chem Soc 2019; 141:7628-7636. [DOI: 10.1021/jacs.9b03505] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Fabio Riefolo
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute for Science and Technology (BIST), Carrer de Baldiri Reixac 15-21, 08028 Barcelona, Spain
- Network Biomedical Research Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
| | - Carlo Matera
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute for Science and Technology (BIST), Carrer de Baldiri Reixac 15-21, 08028 Barcelona, Spain
- Network Biomedical Research Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
| | - Aida Garrido-Charles
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute for Science and Technology (BIST), Carrer de Baldiri Reixac 15-21, 08028 Barcelona, Spain
- Network Biomedical Research Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
| | - Alexandre M. J. Gomila
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute for Science and Technology (BIST), Carrer de Baldiri Reixac 15-21, 08028 Barcelona, Spain
- Network Biomedical Research Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
| | - Rosalba Sortino
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute for Science and Technology (BIST), Carrer de Baldiri Reixac 15-21, 08028 Barcelona, Spain
- Network Biomedical Research Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
| | - Luca Agnetta
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, Julius Maximilian University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Enrique Claro
- Institut de Neurociències (INc), and Dept. Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Barcelona, Spain
| | - Roser Masgrau
- Institut de Neurociències (INc), and Dept. Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Barcelona, Spain
| | - Ulrike Holzgrabe
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, Julius Maximilian University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Montserrat Batlle
- Cardiovascular Institute, Hospital Clinic, University of Barcelona (UB), IDIBAPS, 08036 Barcelona, Spain
| | - Michael Decker
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, Julius Maximilian University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Eduard Guasch
- Cardiovascular Institute, Hospital Clinic, University of Barcelona (UB), IDIBAPS, 08036 Barcelona, Spain
- Network Biomedical Research Center in Cardiovascular Diseases (CIBER-CV), 28029 Madrid, Spain
| | - Pau Gorostiza
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute for Science and Technology (BIST), Carrer de Baldiri Reixac 15-21, 08028 Barcelona, Spain
- Network Biomedical Research Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
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Eraso-Pichot A, Brasó-Vives M, Golbano A, Menacho C, Claro E, Galea E, Masgrau R. GSEA of mouse and human mitochondriomes reveals fatty acid oxidation in astrocytes. Glia 2018; 66:1724-1735. [PMID: 29575211 DOI: 10.1002/glia.23330] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/27/2018] [Accepted: 03/05/2018] [Indexed: 12/18/2022]
Abstract
The prevalent view in neuroenergetics is that glucose is the main brain fuel, with neurons being mostly oxidative and astrocytes glycolytic. Evidence supporting that astrocyte mitochondria are functional has been overlooked. Here we sought to determine what is unique about astrocyte mitochondria by performing unbiased statistical comparisons of the mitochondriome in astrocytes and neurons. Using MitoCarta, a compendium of mitochondrial proteins, together with transcriptomes of mouse neurons and astrocytes, we generated cell-specific databases of nuclear genes encoding for mitochondrion proteins, ranked according to relative expression. Standard and in-house Gene Set Enrichment Analyses (GSEA) of five mouse transcriptomes revealed that genes encoding for enzymes involved in fatty acid oxidation (FAO) and amino acid catabolism are consistently more expressed in astrocytes than in neurons. FAO and oxidative-metabolism-related genes are also up-regulated in human cortical astrocytes versus the whole cortex, and in adult astrocytes versus fetal astrocytes. We thus present the first evidence of FAO in human astrocytes. Further, as shown in vitro, FAO coexists with glycolysis in astrocytes and is inhibited by glutamate. Altogether, these analyses provide arguments against the glucose-centered view of energy metabolism in astrocytes and reveal mitochondria as specialized organelles in these cells.
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Affiliation(s)
- Abel Eraso-Pichot
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Marina Brasó-Vives
- Institute of Evolutionary Biology (Universitat Pompeu Fabra - CSIC), PRBB, Barcelona, 08003, Spain
| | - Arantxa Golbano
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Carmen Menacho
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Enrique Claro
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Elena Galea
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain.,ICREA, Passeig Lluís Companys 23, Barcelona, 08010, Spain
| | - Roser Masgrau
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, i Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
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Pardo L, Valor LM, Eraso-Pichot A, Barco A, Golbano A, Hardingham GE, Masgrau R, Galea E. CREB Regulates Distinct Adaptive Transcriptional Programs in Astrocytes and Neurons. Sci Rep 2017; 7:6390. [PMID: 28743894 PMCID: PMC5526874 DOI: 10.1038/s41598-017-06231-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 06/12/2017] [Indexed: 01/04/2023] Open
Abstract
The cyclic AMP response element binding protein (CREB) is a primary hub of activity-driven genetic programs in neurons controlling plasticity, neurogenesis and survival. By contrast, the gene networks coordinated by CREB in astrocytes are unknown despite the fact that the astrocytic CREB is also activity-driven and neuroprotective. Herein we identified the transcriptional programs regulated by CREB in astrocytes as compared to neurons using, as study materials, transcriptome databases of astrocyte exposed to well-known activators of CREB-dependent transcription as well as publicly available transcriptomes of neuronal cultures. Functional CREB signatures were extracted from the transcriptomes using Gene Ontology, adult-brain gene lists generated by Translating Ribosome Affinity Purification (TRAP) and CREB-target gene repositories. We found minimal overlap between CREB signatures in astrocytes and neurons. In astrocytes, the top triad of functions regulated by CREB consists of 'Gene expression', 'Mitochondria', and 'Signalling', while in neurons it is 'Neurotransmission', 'Signalling' and 'Gene expression', the latter two being represented by different genes from those in astrocytes. The newly generated databases will provide a tool to explore novel means whereby CREB impinges on brain functions requiring adaptive, long-lasting changes by coordinating transcriptional cascades in astrocytes.
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Affiliation(s)
- Luis Pardo
- Institut de Neurociències and Unitat de Bioquímica, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain.
| | - Luis Miguel Valor
- Unidad de Investigación, Hospital Universitario Puerta del Mar, Av. Ana de Viya 21, 11009, Cádiz, Spain
| | - Abel Eraso-Pichot
- Institut de Neurociències and Unitat de Bioquímica, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Angel Barco
- Instituto de Neurociencias, Universidad Miguel Hernández/Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, 03550, Alicante, Spain
| | - Arantxa Golbano
- Institut de Neurociències and Unitat de Bioquímica, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Giles E Hardingham
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.,Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Roser Masgrau
- Institut de Neurociències and Unitat de Bioquímica, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Elena Galea
- Institut de Neurociències and Unitat de Bioquímica, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain. .,ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain.
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Larramona R, Cobos C, Eraso‐Pichot A, Golbano A, Menacho C, Masgrau R, Galea E. [P4–431]: MITOCHONDRION HYPERFUSION AND HYPERMOTILITY IN APOE4 ASTROCYTES. Alzheimers Dement 2017. [DOI: 10.1016/j.jalz.2017.07.591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Raquel Larramona
- Universitat Autònoma de BarcelonaBellaterraSpain
- ICREABarcelonaSpain
| | | | | | | | | | | | - Elena Galea
- Universitat Autònoma de BarcelonaBellaterraSpain
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Masgrau R, Guaza C, Ransohoff RM, Galea E. Should We Stop Saying 'Glia' and 'Neuroinflammation'? Trends Mol Med 2017; 23:486-500. [PMID: 28499701 DOI: 10.1016/j.molmed.2017.04.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 12/15/2022]
Abstract
Central nervous system (CNS) therapeutics based on the theoretical framework of neuroinflammation have only barely succeeded. We argue that a problem may be the wrong use of the term 'neuroinflammation' as a distinct nosological entity when, based on recent evidence, it may not explain CNS disease pathology. Indeed, the terms 'neuroinflammation' and 'glia' could be obsolete. First, unbiased molecular profiling of CNS cell populations and individual cells reveals striking phenotypic heterogeneity in health and disease. Second, astrocytes, microglia, oligodendrocytes, and NG2 cells may contribute to higher-brain functions by performing actions beyond housekeeping. We propose that CNS diseases be viewed as failed circuits caused in part by disease-specific dysfunction of cells traditionally called 'glia', and hence, favor therapies promoting their functional recovery.
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Affiliation(s)
- Roser Masgrau
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Carmen Guaza
- Neuroimmunology Group, Functional and Systems Neurobiology Department, Instituto Cajal, Agencia Estatal del Consejo Superior de Investigaciones Científicas, Madrid, España; Spanish Network of Multiple Sclerosis, RETICS, Instituto de Salud Carlos III, Madrid, España
| | | | - Elena Galea
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain; ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain.
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Hasel P, Dando O, Jiwaji Z, Baxter P, Todd AC, Heron S, Márkus NM, McQueen J, Hampton DW, Torvell M, Tiwari SS, McKay S, Eraso-Pichot A, Zorzano A, Masgrau R, Galea E, Chandran S, Wyllie DJA, Simpson TI, Hardingham GE. Neurons and neuronal activity control gene expression in astrocytes to regulate their development and metabolism. Nat Commun 2017; 8:15132. [PMID: 28462931 PMCID: PMC5418577 DOI: 10.1038/ncomms15132] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 03/02/2017] [Indexed: 12/17/2022] Open
Abstract
The influence that neurons exert on astrocytic function is poorly understood. To investigate this, we first developed a system combining cortical neurons and astrocytes from closely related species, followed by RNA-seq and in silico species separation. This approach uncovers a wide programme of neuron-induced astrocytic gene expression, involving Notch signalling, which drives and maintains astrocytic maturity and neurotransmitter uptake function, is conserved in human development, and is disrupted by neurodegeneration. Separately, hundreds of astrocytic genes are acutely regulated by synaptic activity via mechanisms involving cAMP/PKA-dependent CREB activation. This includes the coordinated activity-dependent upregulation of major astrocytic components of the astrocyte-neuron lactate shuttle, leading to a CREB-dependent increase in astrocytic glucose metabolism and elevated lactate export. Moreover, the groups of astrocytic genes induced by neurons or neuronal activity both show age-dependent decline in humans. Thus, neurons and neuronal activity regulate the astrocytic transcriptome with the potential to shape astrocyte-neuron metabolic cooperation.
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Affiliation(s)
- Philip Hasel
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Owen Dando
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4SB, UK
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, National Centre for Biological Sciences, Bangalore 560065, India
| | - Zoeb Jiwaji
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Paul Baxter
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Alison C. Todd
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Samuel Heron
- School of Informatics, University of Edinburgh, Edinburgh EH8 9AB, UK
| | - Nóra M. Márkus
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Jamie McQueen
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - David W. Hampton
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Megan Torvell
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Sachin S. Tiwari
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Sean McKay
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Abel Eraso-Pichot
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, Barcelona 08193, Spain
| | - Antonio Zorzano
- Institute for Research in Biomedicine, Barcelona 08028, Spain
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona 08028, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ISCIII), Madrid 28029, Spain
| | - Roser Masgrau
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, Barcelona 08193, Spain
| | - Elena Galea
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Medicina, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, Barcelona 08193, Spain
- Institució Catalana De Recerca I Estudis Avançats (ICREA), Passeig Lluís Companys 23, Barcelona, Catalonia, 08010, Spain
| | - Siddharthan Chandran
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4SB, UK
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, National Centre for Biological Sciences, Bangalore 560065, India
| | - David J. A. Wyllie
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - T. Ian Simpson
- School of Informatics, University of Edinburgh, Edinburgh EH8 9AB, UK
| | - Giles E. Hardingham
- Deanery of Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9XD, UK
- 10UK Dementia Research Institute at The University of Edinburgh, Edinburgh Medical School, 47 Little France Crescent, Edinburgh EH16 4TJ, , UK
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9
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Eraso-Pichot A, Larramona-Arcas R, Vicario-Orri E, Villalonga R, Pardo L, Galea E, Masgrau R. CREB decreases astrocytic excitability by modifying subcellular calcium fluxes via the sigma-1 receptor. Cell Mol Life Sci 2017; 74:937-950. [PMID: 27761593 DOI: 10.1007/s00018-016-2397-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 10/04/2016] [Accepted: 10/10/2016] [Indexed: 12/15/2022]
Abstract
Astrocytic excitability relies on cytosolic calcium increases as a key mechanism, whereby astrocytes contribute to synaptic transmission and hence learning and memory. While it is a cornerstone of neurosciences that experiences are remembered, because transmitters activate gene expression in neurons, long-term adaptive astrocyte plasticity has not been described. Here, we investigated whether the transcription factor CREB mediates adaptive plasticity-like phenomena in astrocytes. We found that activation of CREB-dependent transcription reduced the calcium responses induced by ATP, noradrenaline, or endothelin-1. As to the mechanism, expression of VP16-CREB, a constitutively active CREB mutant, had no effect on basal cytosolic calcium levels, extracellular calcium entry, or calcium mobilization from lysosomal-related acidic stores. Rather, VP16-CREB upregulated sigma-1 receptor expression thereby increasing the release of calcium from the endoplasmic reticulum and its uptake by mitochondria. Sigma-1 receptor was also upregulated in vivo upon VP16-CREB expression in astrocytes. We conclude that CREB decreases astrocyte responsiveness by increasing calcium signalling at the endoplasmic reticulum-mitochondria interface, which might be an astrocyte-based form of long-term depression.
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Affiliation(s)
- A Eraso-Pichot
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
| | - R Larramona-Arcas
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
| | - E Vicario-Orri
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
- Department of Neurosciences, School of Medicine, University of California, 9500 Gilman Dr, La Jolla, CA, 92093, USA
| | - R Villalonga
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
| | - L Pardo
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
| | - E Galea
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain.
- Institució Catalana De Recerca I Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010, Barcelona, Catalonia, Spain.
| | - R Masgrau
- Unitat de Bioquímica de Medicina, Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Edifici M, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain.
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10
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Pardo L, Schlüter A, Valor LM, Barco A, Giralt M, Golbano A, Hidalgo J, Jia P, Zhao Z, Jové M, Portero-Otin M, Ruiz M, Giménez-Llort L, Masgrau R, Pujol A, Galea E. Targeted activation of CREB in reactive astrocytes is neuroprotective in focal acute cortical injury. Glia 2016; 64:853-74. [PMID: 26880229 DOI: 10.1002/glia.22969] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 01/07/2023]
Abstract
The clinical challenge in acute injury as in traumatic brain injury (TBI) is to halt the delayed neuronal loss that occurs hours and days after the insult. Here we report that the activation of CREB-dependent transcription in reactive astrocytes prevents secondary injury in cerebral cortex after experimental TBI. The study was performed in a novel bitransgenic mouse in which a constitutively active CREB, VP16-CREB, was targeted to astrocytes with the Tet-Off system. Using histochemistry, qPCR, and gene profiling we found less neuronal death and damage, reduced macrophage infiltration, preserved mitochondria, and rescued expression of genes related to mitochondrial metabolism in bitransgenic mice as compared to wild type littermates. Finally, with meta-analyses using publicly available databases we identified a core set of VP16-CREB candidate target genes that may account for the neuroprotective effect. Enhancing CREB activity in astrocytes thus emerges as a novel avenue in acute brain post-injury therapeutics.
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Affiliation(s)
- Luis Pardo
- Institut De Neurociències and Unitat De Bioquímica, Facultat De Medicina, Universitat Autònoma De Barcelona, Bellaterra, Barcelona, 08193, Spain
| | - Agatha Schlüter
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, L'hospitalet De Llobregat, Barcelona, 08907, Spain
| | - Luis M Valor
- Instituto De Neurociencias De Alicante, Universidad Miguel Hernández/Consejo Superior De Investigaciones Científicas, Sant Joan D'alacant, Alicante, 03550, Spain
| | - Angel Barco
- Instituto De Neurociencias De Alicante, Universidad Miguel Hernández/Consejo Superior De Investigaciones Científicas, Sant Joan D'alacant, Alicante, 03550, Spain
| | - Mercedes Giralt
- Institut De Neurociències and Department of Cellular Biology, Physiology and Immunology, Faculty of Biosciences, Universitat Autònoma, Barcelona, 08193, Spain
| | - Arantxa Golbano
- Institut De Neurociències and Unitat De Bioquímica, Facultat De Medicina, Universitat Autònoma De Barcelona, Bellaterra, Barcelona, 08193, Spain
| | - Juan Hidalgo
- Institut De Neurociències and Department of Cellular Biology, Physiology and Immunology, Faculty of Biosciences, Universitat Autònoma, Barcelona, 08193, Spain
| | - Peilin Jia
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee.,Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Zhongming Zhao
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee.,Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Mariona Jové
- Department of Experimental Medicine, University of Lleida-Biomedical Research Institute of Lleida, Lleida, 25198, Spain
| | - Manuel Portero-Otin
- Department of Experimental Medicine, University of Lleida-Biomedical Research Institute of Lleida, Lleida, 25198, Spain
| | - Montserrat Ruiz
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, L'hospitalet De Llobregat, Barcelona, 08907, Spain
| | - Lydia Giménez-Llort
- Institut De Neurociènces and Department of Psychiatry and Forensic Medicine, School of Medicine, Universitat Autònoma De Barcelona, Bellaterra, 08193, Spain
| | - Roser Masgrau
- Institut De Neurociències and Unitat De Bioquímica, Facultat De Medicina, Universitat Autònoma De Barcelona, Bellaterra, Barcelona, 08193, Spain
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, L'hospitalet De Llobregat, Barcelona, 08907, Spain.,Institució Catalana De Recerca I Estudis Avançats (ICREA), Barcelona, Spain
| | - Elena Galea
- Institut De Neurociències and Unitat De Bioquímica, Facultat De Medicina, Universitat Autònoma De Barcelona, Bellaterra, Barcelona, 08193, Spain.,Institució Catalana De Recerca I Estudis Avançats (ICREA), Barcelona, Spain
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11
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Melachroinou K, Xilouri M, Emmanouilidou E, Masgrau R, Papazafiri P, Stefanis L, Vekrellis K. Deregulation of calcium homeostasis mediates secreted α-synuclein-induced neurotoxicity. Neurobiol Aging 2013; 34:2853-65. [PMID: 23891486 DOI: 10.1016/j.neurobiolaging.2013.06.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 06/04/2013] [Accepted: 06/14/2013] [Indexed: 01/24/2023]
Abstract
α-Synuclein (AS) plays a crucial role in Parkinson's disease pathogenesis. AS is normally secreted from neuronal cells and can thus exert paracrine effects. We have previously demonstrated that naturally secreted AS species, derived from SH-SY5Y cells inducibly overexpressing human wild type AS, can be toxic to recipient neuronal cells. In the current study, we show that application of secreted AS alters membrane fluidity and increases calcium (Ca2+) entry. This influx is reduced on pharmacological inhibition of voltage-operated Ca2+ channels. Although no change in free cytosolic Ca2+ levels is observed, a significantly increased mitochondrial Ca2+ sequestration is found in recipient cells. Application of voltage-operated Ca2+ channel blockers or Ca2+ chelators abolishes AS-mediated toxicity. AS-treated cells exhibit increased calpain activation, and calpain inhibition greatly alleviates the observed toxicity. Collectively, our data suggest that secreted AS exerts toxicity through engagement, at least in part, of the Ca2+ homeostatic machinery. Therefore, manipulating Ca2+ signaling pathways might represent a potential therapeutic strategy for Parkinson's disease.
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Affiliation(s)
- Katerina Melachroinou
- Division of Basic Neurosciences, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
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12
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Lewis AM, Aley PK, Roomi A, Thomas JM, Masgrau R, Garnham C, Shipman K, Paramore C, Bloor-Young D, Sanders LEL, Terrar DA, Galione A, Churchill GC. β-Adrenergic receptor signaling increases NAADP and cADPR levels in the heart. Biochem Biophys Res Commun 2012; 427:326-9. [PMID: 22995315 DOI: 10.1016/j.bbrc.2012.09.054] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 09/10/2012] [Indexed: 10/27/2022]
Abstract
Evidence suggests that β-Adrenergic receptor signaling increases heart rate and force through not just cyclic AMP but also the Ca(2+)-releasing second messengers NAADP (nicotinic acid adenine dinucleotide phosphate) and cADPR (cyclic ADP-ribose). Nevertheless, proof of the physiological relevance of these messengers requires direct measurements of their levels in response to receptor stimulation. Here we report that in intact Langendorff-perfused hearts β-adrenergic stimulation increased both messengers, with NAADP being transient and cADPR being sustained. Both NAADP and cADPR have physiological and therefore pathological relevance by providing alternative drug targets in the β-adrenergic receptor signaling pathway.
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Affiliation(s)
- Alexander M Lewis
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
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13
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Carriba P, Pardo L, Parra-Damas A, Lichtenstein MP, Saura CA, Pujol A, Masgrau R, Galea E. ATP and noradrenaline activate CREB in astrocytes via noncanonical Ca(2+) and cyclic AMP independent pathways. Glia 2012; 60:1330-44. [PMID: 22593004 DOI: 10.1002/glia.22352] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 04/20/2012] [Indexed: 12/20/2022]
Abstract
In neurons, it is well established that CREB contributes to learning and memory by orchestrating the translation of experience into the activity-dependent (i.e., driven by neurotransmitters) transcription of plasticity-related genes. The activity-dependent CREB-triggered transcription requires the concerted action of cyclic AMP/protein kinase A and Ca(2+) /calcineurin via the CREB-regulated transcription co-activator (CRTC). It is not known, however, whether a comparable molecular sequence occurs in astrocytes, despite the unquestionable contribution of these cells to brain plasticity. Here we sought to determine whether and how ATP and noradrenaline cause CREB-dependent transcription in rat cortical astrocyte cultures. Both transmitters induced CREB phosphorylation (Western Blots), CREB-dependent transcription (CRE-luciferase reporter assays), and the transcription of Bdnf, a canonical regulator of synaptic plasticity (quantitative RT-PCR). We indentified a Ca(2+) and diacylglycerol-independent protein kinase C at the uppermost position of the cascade leading to CREB-dependent transcription. Notably, CREB-dependent transcription was partially dependent on ERK1/2 and CRTC, but independent of cyclic AMP/protein kinase A or Ca(2+) /calcineurin. We conclude that ATP and noradrenaline activate CREB-dependent transcription in cortical astrocytes via an atypical protein kinase C. It is of relevance that the signaling involved be starkly different to the one described in neurons since there is no convergence of Ca(2+) and cyclic AMP-dependent pathways on CRTC, which, moreover, exerts a modulatory rather than a central role. Our data thus point to the existence of an alternative, non-neuronal, glia-based role of CREB in plasticity.
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Affiliation(s)
- Paulina Carriba
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
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14
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Martiáñez T, Carrascal M, Lamarca A, Segura M, Durany N, Masgrau R, Abian J, Gella A. UTP affects the Schwannoma cell line proteome through P2Y receptors leading to cytoskeletal reorganisation. Proteomics 2011; 12:145-56. [PMID: 22065602 DOI: 10.1002/pmic.201100187] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 09/09/2011] [Accepted: 10/19/2011] [Indexed: 12/23/2022]
Abstract
Glial cells in the peripheral nervous system, such as Schwann cells, respond to nucleotides, which play an important role in axonal regeneration and myelination. Metabotropic P2Y receptor agonists are promising therapeutic molecules for peripheral neuropathies. Nevertheless, the proteomic mechanisms involved in nucleotide action on Schwann cells remain unknown. Here, we studied intracellular protein changes in RT4-D6P2T Schwann cells after treatment with nucleotides and Nucleo CMP Forte (CMPF), a nucleotide-based drug. After treatment with CMPF, 2-D DIGE revealed 11 differential gel spots, which were all upregulated. Among these, six different proteins were identified by MS. Some of these proteins are involved in actin remodelling (actin-related protein, Arp3), membrane vesicle transport (Rab GDP dissociation inhibitor β, Rab GDI), and the endoplasmic reticulum stress response (protein disulfide isomerase A3, PDI), which are hallmarks of a possible P2Y receptor signalling pathway. Expression of P2Y receptors in RT4-D6P2T cells was demonstrated by RT-PCR and a transient elevation of intracellular calcium measured in response to UTP. Actin reorganisation was visualized after UTP treatment using phalloidin-FITC staining and was blocked by the P2Y antagonist suramin, which also inhibited Arp3, Rab GDI, and PDI protein upregulation. Our data indicate that extracellular UTP interacts with Schwann P2Y receptors and activates molecular machinery that induces changes in the glial cell cytoskeleton.
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Affiliation(s)
- Tánia Martiáñez
- Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Josep Trueta s/n, Sant Cugat del Vallès, Spain
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15
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Barceló-Torns M, Lewis AM, Gubern A, Barneda D, Bloor-Young D, Picatoste F, Churchill GC, Claro E, Masgrau R. NAADP mediates ATP-induced Ca2+ signals in astrocytes. FEBS Lett 2011; 585:2300-6. [PMID: 21664355 DOI: 10.1016/j.febslet.2011.05.062] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 11/17/2022]
Abstract
Intracellular Ca(2+) signals provide astrocytes with a specific form of excitability that enables them to regulate synaptic transmission. In this study, we demonstrate that NAADP-AM, a membrane-permeant analogue of the new second messenger nicotinic acid-adenine dinucleotide phosphate (NAADP), mobilizes Ca(2+) in astrocytes and that the response is blocked by Ned-19, an antagonist of NAADP signalling. We also show that NAADP receptors are expressed in lysosome-related acidic vesicles. Pharmacological disruption of either NAADP or lysosomal signalling reduced Ca(2+) responses induced by ATP and endothelin-1, but not by bradykinin. Furthermore, ATP increased endogenous NAADP levels. Overall, our data provide evidence for NAADP being an intracellular messenger for agonist-mediated calcium signalling in astrocytes.
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Affiliation(s)
- Miquel Barceló-Torns
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
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16
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Lichtenstein MP, Carriba P, Masgrau R, Pujol A, Galea E. Staging anti-inflammatory therapy in Alzheimer's disease. Front Aging Neurosci 2010; 2:142. [PMID: 21152343 PMCID: PMC2998033 DOI: 10.3389/fnagi.2010.00142] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 09/16/2010] [Indexed: 01/25/2023] Open
Abstract
The use of non-steroidal anti-inflammatory drugs (NSAIDs) in Alzheimer's disease (AD) is controversial because conclusions from numerous epidemiological studies reporting delayed onset of AD in NSAID users have not been corroborated in clinical trials. The purpose of this personal view is to revise the case for NSAIDs in AD therapeutics in light of: (i) the last report from the only primary prevention trial in AD, ADAPT, which, although incomplete, points to significant protection in long-term naproxen users, and (ii) the recently proposed dynamic model of AD evolution. The model contends that there is a clinical silent phase in AD that can last up to 20 years, the duration depending on life style habits, genetic factors, or cognitive reserve. The failure of many purported disease-modifying drugs in AD clinical trials is forcing the view that treatments will only be efficacious if administered pre-clinically. Here we will argue that NSAIDs failed in clinical trials because they are disease-modifying drugs, and they should be administered in early stages of the disease. A complete prevention trial in cognitively normal individuals is thus called for. Further, the shift of anti-inflammatory treatment to early stages uncovers a knowledge void about the targets of NSAIDs in asymptomatic individuals. AD researchers have mostly relied on post-mortem analysis of Aβ plaque-laden brains from demented patients or animal models, thus drawing conclusions about AD pathogenesis based on late symptoms. We will discuss evidence in support that defective, not excessive, inflammation underlies AD pathogenesis, that NSAIDs are multifunctional drugs acting on inflammatory and non-inflammatory targets, and that astrocytes and microglia may play differing roles in disease progression, with an emphasis of ApoEε4 as a key, undervalued target of NSAIDs. According to a meta-analysis of epidemiological data, NSAIDs afford an average protection of 58%. If this figure is true, and translated into patient numbers, NSAID treatment may revive as a worth pursuing strategy to significantly reduce the socio-economical burden imposed by AD.
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17
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Gubern A, Barceló-Torns M, Barneda D, López JM, Masgrau R, Picatoste F, Chalfant CE, Balsinde J, Balboa MA, Claro E. JNK and ceramide kinase govern the biogenesis of lipid droplets through activation of group IVA phospholipase A2. J Biol Chem 2009; 284:32359-69. [PMID: 19778898 DOI: 10.1074/jbc.m109.061515] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The biogenesis of lipid droplets (LD) induced by serum depends on group IVA phospholipase A(2) (cPLA(2)alpha). This work dissects the pathway leading to cPLA(2)alpha activation and LD biogenesis. Both processes were Ca(2+)-independent, as they took place after pharmacological blockade of Ca(2+) transients elicited by serum or chelation with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester). The single mutation D43N in cPLA(2)alpha, which abrogates its Ca(2+) binding capacity and translocation to membranes, did not affect enzyme activation and formation of LD. In contrast, the mutation S505A did not affect membrane relocation of the enzyme in response to Ca(2+) but prevented its phosphorylation, activation, and the appearance of LD. Expression of specific activators of different mitogen-activated protein kinases showed that phosphorylation of cPLA(2)alpha at Ser-505 is due to JNK. This was confirmed by pharmacological inhibition and expression of a dominant-negative form of the upstream activator MEKK1. LD biogenesis was accompanied by increased synthesis of ceramide 1-phosphate. Overexpression of its synthesizing enzyme ceramide kinase increased phosphorylation of cPLA(2)alpha at Ser-505 and formation of LD, and its down-regulation blocked the phosphorylation of cPLA(2)alpha and LD biogenesis. These results demonstrate that LD biogenesis induced by serum is regulated by JNK and ceramide kinase.
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Affiliation(s)
- Albert Gubern
- Institut de Neurociències i Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, E-08193 Barcelona, Spain
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18
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Gubern A, Barceló-Torns M, Casas J, Barneda D, Masgrau R, Picatoste F, Balsinde J, Balboa MA, Claro E. Lipid droplet biogenesis induced by stress involves triacylglycerol synthesis that depends on group VIA phospholipase A2. J Biol Chem 2008; 284:5697-708. [PMID: 19117952 DOI: 10.1074/jbc.m806173200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
This work investigates the metabolic origin of triacylglycerol (TAG) formed during lipid droplet (LD) biogenesis induced by stress. Cytotoxic inhibitors of fatty acid synthase induced TAG synthesis and LD biogenesis in CHO-K1 cells, in the absence of external sources of fatty acids. TAG synthesis was required for LD biogenesis and was sensitive to inhibition and down-regulation of the expression of group VIA phospholipase A(2) (iPLA(2)-VIA). Induction of stress with acidic pH, C(2)-ceramide, tunicamycin, or deprivation of glucose also stimulated TAG synthesis and LD formation in a manner dependent on iPLA(2)-VIA. Overexpression of the enzyme enhanced TAG synthesis from endogenous fatty acids and LD occurrence. During stress, LD biogenesis but not TAG synthesis required phosphorylation and activation of group IVA PLA(2) (cPLA(2)alpha). The results demonstrate that iPLA(2)-VIA provides fatty acids for TAG synthesis while cPLA(2)alpha allows LD biogenesis. LD biogenesis during stress may be a survival strategy, recycling structural phospholipids into energy-generating substrates.
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Affiliation(s)
- Albert Gubern
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona (UAB), Edifici M2, Campus de la UAB, Barcelona E-08193, Spain
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19
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Masgrau R, Hurel C, Papastefanaki F, Georgopoulou N, Thomaidou D, Matsas R. BM88/Cend1 regulates stimuli-induced intracellular calcium mobilization. Neuropharmacology 2008; 56:598-609. [PMID: 19061903 DOI: 10.1016/j.neuropharm.2008.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 10/24/2008] [Accepted: 10/28/2008] [Indexed: 11/19/2022]
Abstract
In neurogenesis, little is known about signal transduction pathways upstream of gene expression however, mounting evidence suggests that calcium release from internal stores plays a critical role. We have previously demonstrated that BM88 is a neuronal lineage-specific regulator of cell cycle exit and differentiation; we now report a link between BM88 and calcium signaling. Calcium imaging experiments revealed that P2Y-induced calcium mobilization is diminished in mouse neuroblastoma Neuro 2a cells stably transfected with BM88 (N2A-BM88 cells) as compared with N2A cells or N2A cells differentiated with retinoic acid. This effect is not restricted to N2A cells but is also observed in HeLa cells that are transiently transfected with BM88, indicating that cells of both neural and non-neural origin respond similarly. Further, activation of P2Y1 but not purinergic P2X receptors induces proliferation of N2A and to a lesser extent of N2A-BM88 cells. Conversely, knockdown of BM88 facilitates N2A cell proliferation both under stimulating and non-stimulating conditions. Importantly, N2A-BM88 cells are less susceptible to apoptosis triggered by C2-ceramide and exhibit reduced C2-ceramide-induced intracellular calcium release. Higher calcium uptake from mitochondria and/or lower calcium levels inside the endoplasmic reticulum may explain the reduced calcium mobilization in response to BM88. Overall, our data reveal a novel signaling mechanism by which BM88 interferes with calcium release from inositol 1,4,5-trisphosphate-sensitive stores and exerts anti-proliferative and anti-apoptotic functions.
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Affiliation(s)
- Roser Masgrau
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 127 Vassilissis Sofias Avenue, 11521 Athens, Greece.
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20
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Gubern A, Casas J, Barceló-Torns M, Barneda D, de la Rosa X, Masgrau R, Picatoste F, Balsinde J, Balboa MA, Claro E. Group IVA phospholipase A2 is necessary for the biogenesis of lipid droplets. J Biol Chem 2008; 283:27369-27382. [PMID: 18632668 DOI: 10.1074/jbc.m800696200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Lipid droplets (LD) are organelles present in all cell types, consisting of a hydrophobic core of triacylglycerols and cholesteryl esters, surrounded by a monolayer of phospholipids and cholesterol. This work shows that LD biogenesis induced by serum, by long-chain fatty acids, or the combination of both in CHO-K1 cells was prevented by phospholipase A(2) inhibitors with a pharmacological profile consistent with the implication of group IVA cytosolic phospholipase A(2) (cPLA(2)alpha). Knocking down cPLA(2)alpha expression with short interfering RNA was similar to pharmacological inhibition in terms of enzyme activity and LD biogenesis. A Chinese hamster ovary cell clone stably expressing an enhanced green fluorescent protein-cPLA(2)alpha fusion protein (EGFP-cPLA(2)) displayed higher LD occurrence under basal conditions and upon LD induction. Induction of LD took place with concurrent phosphorylation of cPLA(2)alpha at Ser(505). Transfection of a S505A mutant cPLA(2)alpha showed that phosphorylation at Ser(505) is key for enzyme activity and LD formation. cPLA(2)alpha contribution to LD biogenesis was not because of the generation of arachidonic acid, nor was it related to neutral lipid synthesis. cPLA(2)alpha inhibition in cells induced to form LD resulted in the appearance of tubulo-vesicular profiles of the smooth endoplasmic reticulum, compatible with a role of cPLA(2)alpha in the formation of nascent LD from the endoplasmic reticulum.
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Affiliation(s)
- Albert Gubern
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, E-08193 Barcelona
| | - Javier Casas
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, E-47003 Valladolid, Spain
| | - Miquel Barceló-Torns
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, E-08193 Barcelona
| | - David Barneda
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, E-08193 Barcelona
| | - Xavier de la Rosa
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, E-08193 Barcelona
| | - Roser Masgrau
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, E-08193 Barcelona
| | - Fernando Picatoste
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, E-08193 Barcelona
| | - Jesús Balsinde
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, E-47003 Valladolid, Spain
| | - María A Balboa
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, E-47003 Valladolid, Spain
| | - Enrique Claro
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, E-08193 Barcelona.
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Lewis AM, Masgrau R, Vasudevan SR, Yamasaki M, O'Neill JS, Garnham C, James K, Macdonald A, Ziegler M, Galione A, Churchill GC. Refinement of a radioreceptor binding assay for nicotinic acid adenine dinucleotide phosphate. Anal Biochem 2007; 371:26-36. [PMID: 17919448 PMCID: PMC2518627 DOI: 10.1016/j.ab.2007.08.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 08/16/2007] [Accepted: 08/22/2007] [Indexed: 11/07/2022]
Abstract
The measurement of changes in nicotinic acid adenine dinucleotide phosphate (NAADP) levels in cells has been, and remains, key to the investigation of the functions of NAADP as a Ca2+-releasing second messenger. Here we provide details of how to isolate NAADP from cells by extraction with perchloric acid and then measure the NAADP using a radioreceptor assay. We demonstrate that NAADP is neither generated nor broken down during sample processing conditions and that radioreceptor assay is highly selective for the detection of NAADP under cell extract conditions. Furthermore, a number of improvements, such as solid-state detection of the radioactivity, are incorporated to enhance the safety of the procedure. Finally, we have developed a new method to prevent the endogenous metabolism of NAADP by chelating Ca2+ with bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA), thereby reducing the difficulty of catching a small transient rise in NAADP levels. In summary, we have refined and improved a method for measuring NAADP levels and presented it in a manner accessible to a wide range of laboratories. It is expected that this will enhance research in the NAADP field.
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Affiliation(s)
- Alexander M Lewis
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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22
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Yamasaki M, Masgrau R, Morgan AJ, Churchill GC, Patel S, Ashcroft SJH, Galione A. Organelle selection determines agonist-specific Ca2+ signals in pancreatic acinar and beta cells. J Biol Chem 2003; 279:7234-40. [PMID: 14660554 DOI: 10.1074/jbc.m311088200] [Citation(s) in RCA: 173] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
How different extracellular stimuli can evoke different spatiotemporal Ca2+ signals is uncertain. We have elucidated a novel paradigm whereby different agonists use different Ca2+-storing organelles ("organelle selection") to evoke unique responses. Some agonists select the endoplasmic reticulum (ER), and others select lysosome-related (acidic) organelles, evoking spatial Ca2+ responses that mirror the organellar distribution. In pancreatic acinar cells, acetylcholine and bombesin exclusively select the ER Ca2+ store, whereas cholecystokinin additionally recruits a lysosome-related organelle. Similarly, in a pancreatic beta cell line MIN6, acetylcholine selects only the ER, whereas glucose mobilizes Ca2+ from a lysosome-related organelle. We also show that the key to organelle selection is the agonist-specific coupling messenger(s) such that the ER is selected by recruitment of inositol 1,4,5-trisphosphate (or cADP-ribose), whereas lysosome-related organelles are selected by NAADP.
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Affiliation(s)
- Michiko Yamasaki
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
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23
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Masgrau R, Churchill GC, Morgan AJ, Ashcroft SJH, Galione A. NAADP: a new second messenger for glucose-induced Ca2+ responses in clonal pancreatic beta cells. Curr Biol 2003; 13:247-51. [PMID: 12573222 DOI: 10.1016/s0960-9822(03)00041-1] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Important questions remain concerning how elevated blood glucose levels are coupled to insulin secretion from pancreatic beta cells and how this process is impaired in type 2 diabetes. Glucose uptake and metabolism in beta cells cause the intracellular Ca(2+) concentration ([Ca(2+)](i)) to increase to a degree necessary and sufficient for triggering insulin release. Although both Ca(2+) influx and Ca(2+) release from internal stores are critical, the roles of inositol 1,4,5-trisphosphate (IP(3)) and cyclic adenosine dinucleotide phosphate ribose (cADPR) in regulating the latter have proven equivocal. Here we show that glucose also increases [Ca(2+)](i) via the novel Ca(2+)-mobilizing agent nicotinic acid adenine dinucleotide phosphate (NAADP) in the insulin-secreting beta-cell line MIN6. NAADP binds to specific, high-affinity membrane binding sites and at low concentrations elicits robust Ca(2+) responses in intact cells. Higher concentrations of NAADP inactivate NAADP receptors and attenuate the glucose-induced Ca(2+) increases. Importantly, glucose stimulation increases endogenous NAADP levels, providing strong evidence for recruitment of this pathway. In conclusion, our results support a model in which NAADP mediates glucose-induced Ca(2+) signaling in pancreatic beta cells and are the first demonstration in mammalian cells of the presence of endogenous NAADP levels that can be regulated by a physiological stimulus.
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Affiliation(s)
- Roser Masgrau
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom.
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24
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Servitja JM, Masgrau R, Pardo R, Sarri E, von Eichel-Streiber C, Gutkind JS, Picatoste F. Metabotropic glutamate receptors activate phospholipase D in astrocytes through a protein kinase C-dependent and Rho-independent pathway. Neuropharmacology 2003; 44:171-80. [PMID: 12623215 DOI: 10.1016/s0028-3908(02)00361-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors that mediate phospholipase D (PLD) activation in brain, but the mechanism underlying this response remains unclear. Here we used primary cultures of astrocytes as a cell model to explore the mechanism that links mGluRs to PLD. Glutamate activated both phospholipase C (PLC) and PLD with equal potency and this effect was mimicked by L-cysteinesulfinic acid, a putative neurotransmitter previously shown to activate mGluRs coupled to PLD, but not PLC, in adult brain. PLD activation by glutamate was dependent on Ca(2+) mobilization and fully blocked by both protein kinase C (PKC) inhibitors and PKC down-regulation, suggesting that PLD activation is secondary to PLC stimulation. Furthermore, brefeldin A, an inhibitor of ADP-ribosylation factor (ARF) activation, partially inhibited the activation of PLD by glutamate. By contrast, pretreatment of astrocytes with Clostridium difficile toxin B, which inactivates small G proteins of the Rho family (Rho, Rac, and Cdc42), had no effect on PLD stimulation by glutamate. Taken together, these results indicate that PLD activation by mGluRs in astrocytes is dependent on PKC and small G proteins of the ARF family, but does not require Rho proteins.
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Affiliation(s)
- Joan-Marc Servitja
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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25
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Abstract
NAADP is a highly potent mobilizer of Ca(2+), which in turn triggers Ca(2+)-induced Ca(2+) release pathways in a wide range of species. Nevertheless, NAADP is not presently classified as a second messenger because it has not been shown to increase in response to a physiological stimulus. We now report a dramatic increase in NAADP during sea urchin egg fertilization that was largely due to production in sperm upon contacting egg jelly. The NAADP bolus plays a physiological role upon delivery to the egg based on its ability to induce a cortical flash, a depolarization-induced activation of L-type Ca(2+) channels. Moreover, the sperm-induced cortical flash was eliminated in eggs desensitized to NAADP. We conclude that an NAADP increase plays a physiologically relevant role during fertilization and provides the first conclusive demonstration that NAADP is a genuine second messenger.
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Affiliation(s)
- Grant C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Road, OX1 3QT, Oxford, United Kingdom.
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26
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Abstract
cADP-ribose (cADPR), a naturally occurring metabolite of NAD(+), has been shown to be an important regulator of intracellular Ca(2+) release. Considerable evidence suggests that cADPR is the endogenous modulator of the ryanodine receptor (RyR), which mediates Ca(2+)-induced Ca(2+) release (CICR). Indeed, cADPR-mediated Ca(2+) release is subject to functional regulation by other modulators of CICR, including Ca(2+), caffeine and calmodulin. However, the underlying basis behind the effect of such agents on cADPR activity (in particular whether they regulate cADPR binding), as well as the precise nature of the cADPR receptor remains unclear. In the present study, use of (32)P-radiolabelled cADPR has enabled a detailed pharmacological characterization of cADPR-binding sites in sea urchin egg homogenates. We report that cADPR binds specifically to a single class of high affinity receptor. Retainment of binding to membranes after a high-salt wash suggests the involvement of either an integral membrane protein (possibly the RyR itself) or a peripheral protein tightly associated to the membrane. Insensitivity of [(32)P]cADPR binding to either FK506 or rapamycin suggests that this does not concern the FK506-binding protein. Significantly, binding is highly robust, being relatively insensitive to both endogenous and pharmacological modulators of RyR-mediated CICR. In turn, this suggests that such agents modulate cADPR-mediated Ca(2+) release primarily by tuning the 'gain' of the CICR system, upon which cADPR acts, rather than influencing the interaction of cADPR with its target receptor. The exception to this is calmodulin, for which our results indicate an additional role in facilitating cADPR binding.
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Affiliation(s)
- J M Thomas
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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27
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Masgrau R, Servitja JM, Young KW, Pardo R, Sarri E, Nahorski SR, Picatoste F. Characterization of the metabotropic glutamate receptors mediating phospholipase C activation and calcium release in cerebellar granule cells: calcium-dependence of the phospholipase C response. Eur J Neurosci 2001; 13:248-56. [PMID: 11168529 DOI: 10.1046/j.0953-816x.2000.01384.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this study we have determined the metabotropic glutamate receptors (mGluRs) involved in the glutamate activation of phospholipase C (PLC) and Ca(2+) mobilization in cerebellar granule cells at 9 days in vitro; and studied the Ca(2+) modulation of the PLC response. Both PLC activation and Ca(2+) signalling were found to be mediated exclusively by the mGluR1 subtype, although both group I mGluRs, mGluR1 alpha and mGluR5, could be detected in cell extracts. Exposure of cells to medium devoid of Ca(2+) for various times before agonist stimulation reduced the PLC response, which was quickly recovered following the re-exposure of cells to Ca(2+)-containing medium. The extent of the glutamate response correlated well with changes in the cytosolic Ca(2+) concentration. On the other hand, loading of the intracellular Ca(2+) stores by a transient depolarization followed by washing in nondepolarizing buffer, allowed glutamate to release stored Ca(2+) in the majority of cells and enhanced glutamate activation of PLC. Under such conditions, the absence of extracellular Ca(2+) during stimulation and the chelation of cytosolic Ca(2+) with BAPTA/AM inhibited both glutamate-elicited Ca(2+) response and PLC activation. Overall, these results indicate that the mGluR-mediated activation of PLC depends on the presence of extracellular Ca(2+) and can be modulated by moderate changes of cytosolic Ca(2+). Furthermore, ryanodine reduced PLC stimulation by glutamate in predepolarized cells but not in control cells, suggesting that ryanodine receptors could play a role in the potentiation of the mGluR-mediated activation of PLC by Ca(2+) release in predepolarized cells.
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Affiliation(s)
- R Masgrau
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Catalonia, Spain.
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28
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Abstract
Although reactive oxygen species (ROS) are conventionally viewed as toxic by-products of cellular metabolism, a growing body of evidence suggests that they may act as signaling molecules. We have studied the effects of hydrogen peroxide (H(2)O(2))-induced oxidative stress on phospholipid signaling in cultured rat cortical astrocytes. H(2)O(2) stimulated the formation of phosphatidic acid and the accumulation of phosphatidylbutanol, a product of the phospholipase D (PLD)-catalyzed transphosphatidylation reaction. The effect of exogenous H(2)O(2) on the PLD response was mimicked by menadione-induced production of endogenous H(2)O(2). Oxidative stress also elicited inositol phosphate accumulation resulting from phosphoinositide phospholipase C (PLC) activation. The PLD response to H(2)O(2) was totally suppressed by chelation of both extracellular and cytosolic Ca(2+) with EGTA and BAPTA/AM, respectively. Furthermore, H(2)O(2)-induced PLD stimulation was completely abolished by the protein kinase C (PKC) inhibitors bisindolylmaleimide and chelerythrine and by PKC down-regulation. Activation of PLD by H(2)O(2) was also inhibited by the protein-tyrosine kinase inhibitor genistein. Finally, H(2)O(2) also stimulated both PLC and PLD in rat brain cortical slices. These results show for the first time that oxidative stress elicits phospholipid breakdown by both PLC and PLD in rat cultured astrocytes and brain slices.
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Affiliation(s)
- J M Servitja
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Catalonia, Spain.
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29
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Masgrau R, Servitja JM, Sarri E, Young KW, Nahorski SR, Picatoste F. Intracellular Ca2+ stores regulate muscarinic receptor stimulation of phospholipase C in cerebellar granule cells. J Neurochem 2000; 74:818-26. [PMID: 10646535 DOI: 10.1046/j.1471-4159.2000.740818.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Muscarinic receptor activation of phosphoinositide phospholipase C (PLC) has been examined in rat cerebellar granule cells under conditions that modify intracellular Ca2+ stores. Exposure of cells to medium devoid of Ca2+ for various times reduced carbachol stimulation of PLC with a substantial loss (88%) seen at 30 min. A progressive recovery of responses was observed following the reexposure of cells to Ca2+-containing medium (1.3 mM). However, these changes did not appear to result exclusively from changes in the cytosolic Ca2+ concentration ([Ca2+]i), which decreased to a lower steady level (approximately 25 nM decrease in 1-3 min after extracellular omission) and rapidly returned (within 1 min) to control values when extracellular Ca2+ was restored. Only after loading of the intracellular Ca2+ stores through a transient 1-min depolarization of cerebellar granule cells with 40 mM KCl, followed by washing in nondepolarizing buffer, was carbachol able to mobilize intracellular Ca2+. However, the same treatment resulted in an 80% enhancement of carbachol activation of PLC. In other experiments, partial depletion of the Ca2+ stores by pretreatment of cells with thapsigargin and caffeine resulted in an inhibition (18 and 52%, respectively) of the PLC response. Furthermore, chelation of cytosolic Ca2+ with BAPTA/AM did not influence muscarinic activation of PLC in either the control or predepolarized cells. These conditions, however, inhibited both the increase in [Ca2+]i and the PLC activation elicited by 40 mM KCl and abolished carbachol-induced intracellular Ca2+ release in predepolarized cells. Overall, these results suggest that muscarinic receptor activation of PLC in cerebellar granule cells can be modulated by changes in the loading state of the Ca2+ stores.
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Affiliation(s)
- R Masgrau
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Catalonia, Spain
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30
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Abstract
We have studied the activation of phospholipase D (PLD) by glutamate in rat cultured astrocytes by measuring the PLD-catalyzed formation of [32P]phosphatidylbutanol in [32P]Pi-prelabeled cells, stimulated in the presence of butanol. Glutamate elicited the activation of PLD in cortical astrocytes but not in cortical neurons, whereas similar glutamate activation of phosphoinositide phospholipase C was found in both astrocytes and neurons. The extent of PLD stimulation by glutamate was similar in astrocytes from brain cortex and hippocampus, but no effect was found in cerebellar astrocytes. In cortical astrocytes, the glutamate response was insensitive to antagonists of ionotropic glutamate receptors and was reproduced by agonists of metabotropic glutamate receptors (mGluRs) with a rank order of agonist potency similar to that reported for group I mGluR-mediated phosphoinositide phospholipase activation [quisqualate > (S)-3,5-dihydroxyphenylglycine > (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid]. The response to (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid was inhibited by the mGluR antagonist (S)-alpha-methyl-4-carboxyphenylglycine and, less potently, by 1-aminoindan-1,5-dicarboxylic acid and 4-carboxyphenylglycine, two antagonists of group I mGluRs that display higher potency on mGluR1 than on mGluR5. The mGluR5-selective agonist (RS)-2-chloro-5-hydroxyphenylglycine also activated PLD in astrocytes. These findings indicate the involvement of group I mGluRs, most likely mGluR5, in the glutamate activation of PLD in cultured rat cortical astrocytes.
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Affiliation(s)
- J M Servitja
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
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Servitja JM, Masgrau R, Sarri E, Picatoste F. Involvement of ET(A) and ET(B) receptors in the activation of phospholipase D by endothelins in cultured rat cortical astrocytes. Br J Pharmacol 1998; 124:1728-34. [PMID: 9756390 PMCID: PMC1565560 DOI: 10.1038/sj.bjp.0701997] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This study was performed to characterize the receptor subtypes involved in the endothelin stimulation of phospholipase D (PLD) in rat cortical astrocytes in primary culture. PLD activity was determined by measuring the formation of [32P]phosphatidylbutanol in [32P]orthophosphate prelabelled cells stimulated in the presence of 25 mM butanol. The agonists endothelin-1 (ET-1), endothelin-3 (ET-3), sarafotoxin 6c (S6c) and IRL 1620 elicited PLD activation in a concentration-dependent manner. The potencies of ET-1, ET-3 and S6c were similar. The maximal effects evoked by the ET(B)-preferring agonists, ET-3, S6c and IRL 1620, were significantly lower than the maximal response to the non-selective agonist ET-1. The response to 1 nM ET-1 was inhibited by increasing concentrations of the ET(A) receptor antagonist BQ-123 in a biphasic manner. A high potency component of the inhibition curve (24.2+/-3.5% of the ET-1 response) was defined at low (up to 1 microM) concentrations of BQ-123, yielding an estimated Ki value for BQ-123 of 21.3+/-2.5 nM. In addition, the presence of 1 microM BQ-123 significantly reduced the maximal response to ET-1 but did not change the pD2 value. Increasing concentrations of the ET(B) selective antagonist BQ-788 inhibited the S6c response with a Ki of 17.8+/-0.8 nM. BQ-788 also inhibited the effect of ET-1, although, in this case, two components were defined, accounting for approximately 50% of the response, and showing Ki values of 20.9+/-5.1 nM and 439+/-110 nM, respectively. The ET-1 concentration-response curve was shifted to the right by 1 microM BQ-788, also revealing two components. Only one of them, corresponding to 69.8+/-4.4% of the response, was sensitive to BQ-788 which showed a Ki value of 28.8+/-8.9 nM. Rapid desensitization was achieved by preincubation with ET-1 or S6c. In cells pretreated with S6c neither ET-3 nor S6c activated PLD, but ET-1 still induced approximately 40% of the response shown by non-desensitised cells. This remaining response was insensitive to BQ-788, but fully inhibited by BQ-123. In conclusion, endothelins activate PLD in rat cortical astrocytes acting through both ET(A) and ET(B) receptors, and this response desensitizes rapidly in an apparently homologous fashion. The percentage contribution of ET(A) and ET(B) receptors to the ET-1 response was found to be approximately 20% and 80%, respectively, when ET(B) receptors were not blocked, and 30-50% and 50-70%, respectively, when ET(B) receptors were inhibited or desensitized. These results may be relevant to the study of a possible role of PLD in the proliferative effects shown by endothelins on cultured and reactive astrocytes.
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Affiliation(s)
- J M Servitja
- Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
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