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Birgbauer E. Lysophosphatidic Acid Signalling in Nervous System Development and Function. Neuromolecular Med 2020; 23:68-85. [PMID: 33151452 DOI: 10.1007/s12017-020-08630-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/30/2020] [Indexed: 02/06/2023]
Abstract
One class of molecules that are now coming to be recognized as essential for our understanding of the nervous system are the lysophospholipids. One of the major signaling lysophospholipids is lysophosphatidic acid, also known as LPA. LPA activates a variety of G protein-coupled receptors (GPCRs) leading to a multitude of physiological responses. In this review, I describe our current understanding of the role of LPA and LPA receptor signaling in the development and function of the nervous system, especially the central nervous system (CNS). In addition, I highlight how aberrant LPA receptor signaling may underlie neuropathological conditions, with important clinical application.
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Affiliation(s)
- Eric Birgbauer
- Department of Biology, Winthrop University, Rock Hill, SC, USA.
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2
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The Novel Perspectives of Adipokines on Brain Health. Int J Mol Sci 2019; 20:ijms20225638. [PMID: 31718027 PMCID: PMC6887733 DOI: 10.3390/ijms20225638] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 12/13/2022] Open
Abstract
First seen as a fat-storage tissue, the adipose tissue is considered as a critical player in the endocrine system. Precisely, adipose tissue can produce an array of bioactive factors, including cytokines, lipids, and extracellular vesicles, which target various systemic organ systems to regulate metabolism, homeostasis, and immune response. The global effects of adipokines on metabolic events are well defined, but their impacts on brain function and pathology remain poorly defined. Receptors of adipokines are widely expressed in the brain. Mounting evidence has shown that leptin and adiponectin can cross the blood–brain barrier, while evidence for newly identified adipokines is limited. Significantly, adipocyte secretion is liable to nutritional and metabolic states, where defective circuitry, impaired neuroplasticity, and elevated neuroinflammation are symptomatic. Essentially, neurotrophic and anti-inflammatory properties of adipokines underlie their neuroprotective roles in neurodegenerative diseases. Besides, adipocyte-secreted lipids in the bloodstream can act endocrine on the distant organs. In this article, we have reviewed five adipokines (leptin, adiponectin, chemerin, apelin, visfatin) and two lipokines (palmitoleic acid and lysophosphatidic acid) on their roles involving in eating behavior, neurotrophic and neuroprotective factors in the brain. Understanding and regulating these adipokines can lead to novel therapeutic strategies to counteract metabolic associated eating disorders and neurodegenerative diseases, thus promote brain health.
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Ramesh S, Govindarajulu M, Suppiramaniam V, Moore T, Dhanasekaran M. Autotaxin⁻Lysophosphatidic Acid Signaling in Alzheimer's Disease. Int J Mol Sci 2018; 19:ijms19071827. [PMID: 29933579 PMCID: PMC6073975 DOI: 10.3390/ijms19071827] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/12/2018] [Accepted: 06/18/2018] [Indexed: 12/14/2022] Open
Abstract
The brain contains various forms of lipids that are important for maintaining its structural integrity and regulating various signaling cascades. Autotaxin (ATX) is an ecto-nucleotide pyrophosphatase/phosphodiesterase-2 enzyme that hydrolyzes extracellular lysophospholipids into the lipid mediator lysophosphatidic acid (LPA). LPA is a major bioactive lipid which acts through G protein-coupled receptors (GPCRs) and plays an important role in mediating cellular signaling processes. The majority of synthesized LPA is derived from membrane phospholipids through the action of the secreted enzyme ATX. Both ATX and LPA are highly expressed in the central nervous system. Dysfunctional expression and activity of ATX with associated changes in LPA signaling have recently been implicated in the pathogenesis of Alzheimer’s disease (AD). This review focuses on the current understanding of LPA signaling, with emphasis on the importance of the autotaxin–lysophosphatidic acid (ATX–LPA) pathway and its alterations in AD and a brief note on future therapeutic applications based on ATX–LPA signaling.
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Affiliation(s)
- Sindhu Ramesh
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
| | - Manoj Govindarajulu
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
| | - Vishnu Suppiramaniam
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
| | - Timothy Moore
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
| | - Muralikrishnan Dhanasekaran
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
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González de San Román E, Manuel I, Giralt MT, Chun J, Estivill-Torrús G, Rodríguez de Fonseca F, Santín LJ, Ferrer I, Rodríguez-Puertas R. Anatomical location of LPA1 activation and LPA phospholipid precursors in rodent and human brain. J Neurochem 2015; 134:471-85. [PMID: 25857358 DOI: 10.1111/jnc.13112] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/02/2015] [Accepted: 03/31/2015] [Indexed: 12/29/2022]
Abstract
Lysophosphatidic acid (LPA) is a signaling molecule that binds to six known G protein-coupled receptors: LPA1 -LPA6 . LPA evokes several responses in the CNS, including cortical development and folding, growth of the axonal cone and its retraction process. Those cell processes involve survival, migration, adhesion proliferation, differentiation, and myelination. The anatomical localization of LPA1 is incompletely understood, particularly with regard to LPA binding. Therefore, we have used functional [(35) S]GTPγS autoradiography to verify the anatomical distribution of LPA1 binding sites in adult rodent and human brain. The greatest activity was observed in myelinated areas of the white matter such as corpus callosum, internal capsule and cerebellum. MaLPA1 -null mice (a variant of LPA1 -null) lack [(35) S]GTPγS basal binding in white matter areas, where the LPA1 receptor is expressed at high levels, suggesting a relevant role of the activity of this receptor in the most myelinated brain areas. In addition, phospholipid precursors of LPA were localized by MALDI-IMS in both rodent and human brain slices identifying numerous species of phosphatides and phosphatidylcholines. Both phosphatides and phosphatidylcholines species represent potential LPA precursors. The anatomical distribution of these precursors in rodent and human brain may indicate a metabolic relationship between LPA and LPA1 receptors. Lysophosphatidic acid (LPA) is a signaling molecule that binds to six known G protein-coupled receptors (GPCR), LPA1 to LPA6 . LPA evokes several responses in the central nervous system (CNS), including cortical development and folding, growth of the axonal cone and its retraction process. We used functional [(35) S]GTPγS autoradiography to verify the anatomical distribution of LPA1 -binding sites in adult rodent and human brain. The distribution of LPA1 receptors in rat, mouse and human brains show the highest activity in white matter myelinated areas. The basal and LPA-evoked activities are abolished in MaLPA1 -null mice. The phospholipid precursors of LPA are localized by MALDI-IMS. The anatomical distribution of LPA precursors in rodent and human brain suggests a relationship with functional LPA1 receptors.
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Affiliation(s)
| | - Iván Manuel
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - María Teresa Giralt
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Jerold Chun
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, USA
| | - Guillermo Estivill-Torrús
- UGC Intercentros de Neurociencias y UGC de Salud Mental, Instituto de Investigación Biomédica de Malaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, Universidad de Málaga, Spain
| | - Fernando Rodríguez de Fonseca
- UGC Intercentros de Neurociencias y UGC de Salud Mental, Instituto de Investigación Biomédica de Malaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, Universidad de Málaga, Spain
| | - Luis Javier Santín
- Departmento de Psicobiología y Metodología de las Ciencias del Comportamiento. Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad of Málaga, Málaga, Spain
| | - Isidro Ferrer
- Institute of Neuropathology, University Hospital Bellvitge, University of Barcelona, Ciberned, Spain
| | - Rafael Rodríguez-Puertas
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, UPV/EHU, Leioa, Spain
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Abstract
The brain is composed of many lipids with varied forms that serve not only as structural components but also as essential signaling molecules. Lysophosphatidic acid (LPA) is an important bioactive lipid species that is part of the lysophospholipid (LP) family. LPA is primarily derived from membrane phospholipids and signals through six cognate G protein-coupled receptors (GPCRs), LPA1-6. These receptors are expressed on most cell types within central and peripheral nervous tissues and have been functionally linked to many neural processes and pathways. This Review covers a current understanding of LPA signaling in the nervous system, with particular focus on the relevance of LPA to both physiological and diseased states.
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Affiliation(s)
- Yun C Yung
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nicole C Stoddard
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Biomedical Sciences Graduate Program, University of California, San Diego School of Medicine, La Jolla, CA 92037, USA
| | - Hope Mirendil
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jerold Chun
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037, USA.
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García-Díaz B, Riquelme R, Varela-Nieto I, Jiménez AJ, de Diego I, Gómez-Conde AI, Matas-Rico E, Aguirre JÁ, Chun J, Pedraza C, Santín LJ, Fernández O, Rodríguez de Fonseca F, Estivill-Torrús G. Loss of lysophosphatidic acid receptor LPA1 alters oligodendrocyte differentiation and myelination in the mouse cerebral cortex. Brain Struct Funct 2014; 220:3701-20. [PMID: 25226845 DOI: 10.1007/s00429-014-0885-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 09/08/2014] [Indexed: 12/16/2022]
Abstract
Lysophosphatidic acid (LPA) is an intercellular signaling lipid that regulates multiple cellular functions, acting through specific G-protein coupled receptors (LPA(1-6)). Our previous studies using viable Malaga variant maLPA1-null mice demonstrated the requirement of the LPA1 receptor for normal proliferation, differentiation, and survival of the neuronal precursors. In the cerebral cortex LPA1 is expressed extensively in differentiating oligodendrocytes, in parallel with myelination. Although exogenous LPA-induced effects have been investigated in myelinating cells, the in vivo contribution of LPA1 to normal myelination remains to be demonstrated. This study identified a relevant in vivo role for LPA1 as a regulator of cortical myelination. Immunochemical analysis in adult maLPA1-null mice demonstrated a reduction in the steady-state levels of the myelin proteins MBP, PLP/DM20, and CNPase in the cerebral cortex. The myelin defects were confirmed using magnetic resonance spectroscopy and electron microscopy. Stereological analysis limited the defects to adult differentiating oligodendrocytes, without variation in the NG2+ precursor cells. Finally, a possible mechanism involving oligodendrocyte survival was demonstrated by the impaired intracellular transport of the PLP/DM20 myelin protein which was accompanied by cellular loss, suggesting stress-induced apoptosis. These findings describe a previously uncharacterized in vivo functional role for LPA1 in the regulation of oligodendrocyte differentiation and myelination in the CNS, underlining the importance of the maLPA1-null mouse as a model for the study of demyelinating diseases.
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Affiliation(s)
- Beatriz García-Díaz
- Laboratorio de Investigación, UGC Intercentros de Neurociencias, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, Hospital Civil, Pabellón 5, Planta Sótano, Plaza del Hospital Civil s/n, 29009, Málaga, Spain.,Department of Neurology, H. Houston Merritt Clinical Research Center, Columbia University Medical Center, New York, NY, 10032, USA
| | - Raquel Riquelme
- Instituto de Investigaciones Biomédicas 'Alberto Sols', Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), 28029, Madrid, Spain
| | - Isabel Varela-Nieto
- Instituto de Investigaciones Biomédicas 'Alberto Sols', Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), 28029, Madrid, Spain
| | - Antonio Jesús Jiménez
- Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, 29071, Málaga, Spain
| | - Isabel de Diego
- Departamento de Anatomía y Medicina Legal, Universidad de Málaga, 29071, Málaga, Spain
| | - Ana Isabel Gómez-Conde
- ECAI de Microscopía, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, 29010, Málaga, Spain
| | - Elisa Matas-Rico
- Laboratorio de Investigación, UGC Intercentros de Neurociencias, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, Hospital Civil, Pabellón 5, Planta Sótano, Plaza del Hospital Civil s/n, 29009, Málaga, Spain.,Division of Cell Biology I, The Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - José Ángel Aguirre
- Departamento de Fisiología Humana y Educación Físico Deportiva, Universidad de Málaga, 29071, Málaga, Spain
| | - Jerold Chun
- Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Centre, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Carmen Pedraza
- Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, 29071, Málaga, Spain
| | - Luis Javier Santín
- Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, 29071, Málaga, Spain
| | - Oscar Fernández
- Neurology Service, UGC Intercentros de Neurociencias, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, Universidad de Málaga, 29010, Málaga, Spain
| | - Fernando Rodríguez de Fonseca
- Laboratorio de Medicina Regenerativa, UGC de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Universitario Regional de Málaga, 29010, Málaga, Spain
| | - Guillermo Estivill-Torrús
- Laboratorio de Investigación, UGC Intercentros de Neurociencias, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, Hospital Civil, Pabellón 5, Planta Sótano, Plaza del Hospital Civil s/n, 29009, Málaga, Spain. .,ECAI de Microscopía, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, 29010, Málaga, Spain.
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Goldshmit Y, Matteo R, Sztal T, Ellett F, Frisca F, Moreno K, Crombie D, Lieschke GJ, Currie PD, Sabbadini RA, Pébay A. Blockage of lysophosphatidic acid signaling improves spinal cord injury outcomes. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:978-92. [PMID: 22819724 DOI: 10.1016/j.ajpath.2012.06.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 05/28/2012] [Accepted: 06/07/2012] [Indexed: 01/10/2023]
Abstract
Evidence suggests a proinflammatory role of lysophosphatidic acid (LPA) in various pathologic abnormalities, including in the central nervous system. Herein, we describe LPA as an important mediator of inflammation after spinal cord injury (SCI) in zebrafish and mice. Furthermore, we describe a novel monoclonal blocking antibody raised against LPA that potently inhibits LPA's effect in vitro and in vivo. This antibody, B3, specifically binds LPA, prevents it from interacting with its complement of receptors, and blocks LPA's effects on the neuronal differentiation of human neural stem/progenitor cells, demonstrating its specificity toward LPA signaling. When administered systemically to mice subjected to SCI, B3 substantially reduced glial inflammation and neuronal death. B3-treated animals demonstrated significantly more neuronal survival upstream of the lesion site, with some functional improvement. This study describes the use of anti-LPA monoclonal antibody as a novel therapeutic approach for the treatment of SCI.
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Frisca F, Sabbadini RA, Goldshmit Y, Pébay A. Biological Effects of Lysophosphatidic Acid in the Nervous System. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY VOLUME 296 2012; 296:273-322. [DOI: 10.1016/b978-0-12-394307-1.00005-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Frugier T, Crombie D, Conquest A, Tjhong F, Taylor C, Kulkarni T, McLean C, Pébay A. Modulation of LPA Receptor Expression in the Human Brain Following Neurotrauma. Cell Mol Neurobiol 2011; 31:569-77. [DOI: 10.1007/s10571-011-9650-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 01/05/2011] [Indexed: 01/07/2023]
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Tigyi G. Aiming drug discovery at lysophosphatidic acid targets. Br J Pharmacol 2010; 161:241-70. [PMID: 20735414 PMCID: PMC2989581 DOI: 10.1111/j.1476-5381.2010.00815.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 02/12/2010] [Accepted: 03/20/2010] [Indexed: 12/22/2022] Open
Abstract
Lysophosphatidic acid (LPA, 1-radyl-2-hydroxy-sn-glycero-3-phosphate) is the prototype member of a family of lipid mediators and second messengers. LPA and its naturally occurring analogues interact with G protein-coupled receptors on the cell surface and a nuclear hormone receptor within the cell. In addition, there are several enzymes that utilize LPA as a substrate or generate it as a product and are under its regulatory control. LPA is present in biological fluids, and attempts have been made to link changes in its concentration and molecular composition to specific disease conditions. Through their many targets, members of the LPA family regulate cell survival, apoptosis, motility, shape, differentiation, gene transcription, malignant transformation and more. The present review depicts arbitrary aspects of the physiological and pathophysiological actions of LPA and attempts to link them with select targets. Many of us are now convinced that therapies targeting LPA biosynthesis and signalling are feasible for the treatment of devastating human diseases such as cancer, fibrosis and degenerative conditions. However, successful targeting of the pathways associated with this pleiotropic lipid will depend on the future development of as yet undeveloped pharmacons.
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Affiliation(s)
- Gabor Tigyi
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA.
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Goldshmit Y, Munro K, Leong SY, Pébay A, Turnley AM. LPA receptor expression in the central nervous system in health and following injury. Cell Tissue Res 2010; 341:23-32. [PMID: 20495828 DOI: 10.1007/s00441-010-0977-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 04/06/2010] [Indexed: 11/30/2022]
Abstract
Lysophosphatidic acid (LPA) is released from platelets following injury and also plays a role in neural development but little is known about its effects in the adult central nervous system (CNS). We have examined the expression of LPA receptors 1-3 (LPA(1-3)) in intact mouse spinal cord and cortical tissues and following injury. In intact and injured tissues, LPA(1) was expressed by ependymal cells in the central canal of the spinal cord and was upregulated in reactive astrocytes following spinal cord injury. LPA(2) showed low expression in intact CNS tissue, on grey matter astrocytes in spinal cord and in ependymal cells lining the lateral ventricle. Following injury, its expression was upregulated on astrocytes in both cortex and spinal cord. LPA(3) showed low expression in intact CNS tissue, viz. on cortical neurons and motor neurons in the spinal cord, and was upregulated on neurons in both regions after injury. Therefore, LPA(1-3) are differentially expressed in the CNS and their expression is upregulated in response to injury. LPA release following CNS injury may have different consequences for each cell type because of this differential expression in the adult nervous system.
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Affiliation(s)
- Yona Goldshmit
- Centre for Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
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12
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Parys B, Côté A, Gallo V, De Koninck P, Sík A. Intercellular calcium signaling between astrocytes and oligodendrocytes via gap junctions in culture. Neuroscience 2010; 167:1032-43. [PMID: 20211698 DOI: 10.1016/j.neuroscience.2010.03.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 02/23/2010] [Accepted: 03/02/2010] [Indexed: 11/16/2022]
Abstract
To understand further how oligodendrocytes regulate brain function, the mechanism of communication between oligodendrocytes and other cell types needs to be explored. An important mode of communication between various cell types in the nervous system involves gap junctions. Astroglial cells are extensively connected through gap junctions forming the glial syncytium. Although the presence of gap junctions between oligodendrocytes and astrocytes have been well documented, evidence for gap junction-mediated calcium transfer between these two glial populations is still missing. To measure functional coupling between astrocytes and oligodendrocytes and to test whether this coupling is mediated by gap junctions we used laser photostimulation and monitored Ca(2+) propagation in cultures from transgenic animals in which oligodendrocytes express enhanced green fluorescent protein (eGFP). We show that waves of Ca(2+) spread from astrocytes to oligodendrocytes and that these waves are blocked by the broad-spectrum gap junction blocker carbenoxolone, but not the neuron-specific gap junction blocker quinine. We also show that the spread of Ca(2+) waves between astrocytes and oligodendrocytes is bi-directional. Thus, increase of Ca(2+) concentration in astrocytes triggered by surrounding neuronal activity may feed back onto different neuronal populations through oligodendrocytes.
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Affiliation(s)
- B Parys
- Centre de Recherche Université Laval Robert-Giffard; 2601, chemin de la Canardière, Quebec, QC, G1J 2G3 Canada
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Bernhart E, Kollroser M, Rechberger G, Reicher H, Heinemann A, Schratl P, Hallström S, Wintersperger A, Nusshold C, DeVaney T, Zorn-Pauly K, Malli R, Graier W, Malle E, Sattler W. Lysophosphatidic acid receptor activation affects the C13NJ microglia cell line proteome leading to alterations in glycolysis, motility, and cytoskeletal architecture. Proteomics 2010; 10:141-58. [PMID: 19899077 DOI: 10.1002/pmic.200900195] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microglia, the immunocompetent cells of the CNS, are rapidly activated in response to injury and microglia migration towards and homing at damaged tissue plays a key role in CNS regeneration. Lysophosphatidic acid (LPA) is involved in signaling events evoking microglia responses through cognate G protein-coupled receptors. Here we show that human immortalized C13NJ microglia express LPA receptor subtypes LPA(1), LPA(2), and LPA(3) on mRNA and protein level. LPA activation of C13NJ cells induced Rho and extracellular signal-regulated kinase activation and enhanced cellular ATP production. In addition, LPA induced process retraction, cell spreading, led to pronounced changes of the actin cytoskeleton and reduced cell motility, which could be reversed by inhibition of Rho activity. To get an indication about LPA-induced global alterations in protein expression patterns a 2-D DIGE/LC-ESI-MS proteomic approach was applied. On the proteome level the most prominent changes in response to LPA were observed for glycolytic enzymes and proteins regulating cell motility and/or cytoskeletal dynamics. The present findings suggest that naturally occurring LPA is a potent regulator of microglia biology. This might be of particular relevance in the pathophysiological context of neurodegenerative disorders where LPA concentrations can be significantly elevated in the CNS.
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Affiliation(s)
- Eva Bernhart
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Austria
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Yuelling LM, Fuss B. Autotaxin (ATX): a multi-functional and multi-modular protein possessing enzymatic lysoPLD activity and matricellular properties. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1781:525-30. [PMID: 18485925 PMCID: PMC2564869 DOI: 10.1016/j.bbalip.2008.04.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 04/15/2008] [Accepted: 04/19/2008] [Indexed: 01/02/2023]
Abstract
Recent studies have established that autotaxin (ATX), also known as phosphodiesterase Ialpha/autotaxin (PD-Ialpha/ATX) or (ecto)nucleotide pyrophosphatase/phosphodiesterase 2 [(E)NPP2], represents a multi-functional and multi-modular protein. ATX was initially thought to function exclusively as a phosphodiesterase/pyrophosphatase. However, it has become apparent that this enzymatically active site, which is ultimately responsible for ATX's originally discovered property of tumor cell motility stimulation, mediates the conversion of lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA). In addition, a separate functionally active domain, here referred to as the Modulator of Oligodendrocyte Remodeling and Focal adhesion Organization (MORFO) domain, was discovered in studies analyzing the role of ATX during the differentiation of myelinating cells of the central nervous system (CNS), namely oligodendrocytes. This novel domain was found to mediate anti-adhesive, i.e. matricellular, properties and to promote morphological maturation of oligodendrocytes. In this review, we summarize our current understanding of ATX's structure-function domains and discuss their contribution to the presently known main functional roles of ATX.
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Affiliation(s)
- Larra M Yuelling
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, PO Box 980709, Richmond, VA 23298, USA
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Nogaroli L, Yuelling LM, Dennis J, Gorse K, Payne SG, Fuss B. Lysophosphatidic acid can support the formation of membranous structures and an increase in MBP mRNA levels in differentiating oligodendrocytes. Neurochem Res 2008; 34:182-93. [PMID: 18594965 DOI: 10.1007/s11064-008-9772-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 06/03/2008] [Indexed: 11/29/2022]
Abstract
During development, differentiating oligodendrocytes progress in distinct maturation steps from premyelinating to myelinating cells. Such maturing oligodendrocytes express both the receptors mediating signaling via extracellular lysophosphatidic acid (LPA) and the major enzyme generating extracellular LPA, namely phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX). However, the biological role of extracellular LPA during the maturation of differentiating oligodendrocytes is currently unclear. Here, we demonstrate that application of exogenous LPA induced an increase in the area occupied by the oligodendrocytes' process network, but only when PD-Ialpha/ATX expression was down-regulated. This increase in network area was caused primarily by the formation of membranous structures. In addition, LPA increased the number of cells positive for myelin basic protein (MBP). This effect was associated by an increase in the mRNA levels coding for MBP but not myelin oligodendrocyte glycoprotein (MOG). Taken together, these data suggest that LPA may play a crucial role in regulating the later stages of oligodendrocyte maturation.
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Affiliation(s)
- Luciana Nogaroli
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, PO Box 980709, Richmond, VA 23298, USA
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16
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Abstract
The function of oligodendrocytes is to myelinate CNS axons. Oligodendrocytes and the axons they myelinate are functional units, and neurotransmitters released by axons can influence all stages of oligodendrocyte development via calcium dependent mechanisms. Some of the clearest functional evidence is for adenosine, ATP, and glutamate, which are released by electrically active axons and regulate the migration and proliferation of oligodendrocyte progenitor cells and their differentiation into myelinating oligodendrocytes. Glutamate and ATP, released by both axons and astrocytes, continue to mediate Ca(2+) signaling in mature oligodendrocytes, acting via AMPA and NMDA glutamate receptors, and heterogeneous P2X and P2Y purinoceptors. Physiological signalling between axons, astrocytes, and oligodendrocytes is likely to play an important role in myelin maintenance throughout life. Significantly, ATP- and glutamate-mediated Ca(2+) signaling are also major components of oligodendrocyte and myelin damage in numerous pathologies, most notably ischemia, injury, periventricular leukomalacia, and multiple sclerosis. In addition, NG2-expressing glia (synantocytes) in the adult CNS are highly reactive cells that respond rapidly to any CNS insult by a characteristic gliosis, and are able to regenerate oligodendrocytes and possibly neurons. Glutamate and ATP released by neurons and astrocytes evoke Ca(2+) signaling in NG2-glia (synantocytes), and it is proposed these regulate their differentiation capacity and response to injury. In summary, clear roles have been demonstrated for neurotransmitter-mediated Ca(2+) signaling in oligodendrocyte development and pathology. A key issue for future studies is to determine the physiological roles of neurotransmitters in mature oligodendrocytes and NG2-glia (synantocytes).
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Affiliation(s)
- Arthur M Butt
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
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17
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Dennis J, Nogaroli L, Fuss B. Phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX): a multifunctional protein involved in central nervous system development and disease. J Neurosci Res 2006; 82:737-42. [PMID: 16267828 DOI: 10.1002/jnr.20686] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX) was originally identified as a cell-motility-stimulating factor secreted by a variety of tumor cells. Thus, studies related to its potential functional roles have traditionally focused on tumorigenesis. PD-Ialpha/ATX's catalytic activity, initially defined as nucleotide pyrophosphatase/phosphodiesterase, was soon recognized as being necessary for its tumor cell-motility-stimulating activity. However, only the discovery of PD-Ialpha/ATX's identity with lysophospholipase D, an extracellular enzyme that converts lysophosphatidylcholine into lysophosphatidic acid (LPA) and potentially sphingosylphosphoryl choline into sphingosine 1-phosphate (S1P), revealed the actual effectors responsible for PD-Ialpha/ATX's ascribed motogenic functions, i.e., its catalytic products. PD-Ialpha/ATX has also been detected during normal development in a number of tissues, in particular, the central nervous system (CNS), where expression levels are high. Similar to tumor cells, PD-Ialpha/ATX-expressing CNS cells secrete catalytically active PD-Ialpha/ATX into the extracellular environment. Thus, it appears reasonable to assume that PD-Ialpha/ATX's CNS-related functions are mediated via lysophospholipid, LPA and potentially S1P, signaling. However, recent studies identified PD-Ialpha/ATX as a matricellular protein involved in the modulation of oligodendrocyte-extracellular matrix interactions and oligodendrocyte remodeling. This property of PD-Ialpha/ATX was found to be independent of its catalytic activity and to be mediated by a novel functionally active domain. These findings, therefore, uncover PD-Ialpha/ATX, at least in the CNS, as a multifunctional protein able to induce complex signaling cascades via distinct structure-function domains. This Mini-Review describes PD-Ialpha/ATX's multifunctional roles in the CNS and discusses their potential contributions to CNS development and pathology.
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Affiliation(s)
- Jameel Dennis
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, 23298, USA
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18
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Jaillard C, Harrison S, Stankoff B, Aigrot MS, Calver AR, Duddy G, Walsh FS, Pangalos MN, Arimura N, Kaibuchi K, Zalc B, Lubetzki C. Edg8/S1P5: an oligodendroglial receptor with dual function on process retraction and cell survival. J Neurosci 2005; 25:1459-69. [PMID: 15703400 PMCID: PMC6726002 DOI: 10.1523/jneurosci.4645-04.2005] [Citation(s) in RCA: 259] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Endothelial differentiation gene (Edg) proteins are G-protein-coupled receptors activated by lysophospholipid mediators: sphingosine-1-phosphate (S1P) or lysophosphatidic acid. We show that in the CNS, expression of Edg8/S1P5, a high-affinity S1P receptor, is restricted to oligodendrocytes and expressed throughout development from the immature stages to the mature myelin-forming cell. S1P activation of Edg8/S1P5 on O4-positive pre-oligodendrocytes induced process retraction via a Rho kinase/collapsin response-mediated protein signaling pathway, whereas no retraction was elicited by S1P on these cells derived from Edg8/S1P5-deficient mice. Edg8/S1P5-mediated process retraction was restricted to immature cells and was no longer observed at later developmental stages. In contrast, S1P activation promoted the survival of mature oligodendrocytes but not of pre-oligodendrocytes. The S1P-induced survival of mature oligodendrocytes was mediated through a pertussis toxin-sensitive, Akt-dependent pathway. Our data demonstrate that Edg8/S1P5 activation on oligodendroglial cells modulates two distinct functional pathways mediating either process retraction or cell survival and that these effects depend on the developmental stage of the cell.
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MESH Headings
- Amino Acid Sequence
- Animals
- Ankyrins/analysis
- Brain/cytology
- Brain/growth & development
- Brain Chemistry
- Cell Differentiation
- Cell Lineage
- Cell Shape/drug effects
- Cell Surface Extensions/drug effects
- Cell Surface Extensions/physiology
- Cell Survival/drug effects
- Cells, Cultured/drug effects
- Cells, Cultured/metabolism
- Cells, Cultured/ultrastructure
- Crosses, Genetic
- Female
- GTP-Binding Protein alpha Subunit, Gi2
- GTP-Binding Protein alpha Subunits, Gi-Go/physiology
- Intercellular Signaling Peptides and Proteins
- Intracellular Signaling Peptides and Proteins
- Kv1.1 Potassium Channel
- Lysophospholipids/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Molecular Sequence Data
- Nerve Tissue Proteins/deficiency
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Nerve Tissue Proteins/physiology
- Oligodendroglia/drug effects
- Oligodendroglia/metabolism
- Oligodendroglia/ultrastructure
- Phosphorylation
- Potassium Channels, Voltage-Gated/analysis
- Protein Processing, Post-Translational
- Protein Serine-Threonine Kinases/metabolism
- Protein Serine-Threonine Kinases/physiology
- Proto-Oncogene Proteins/physiology
- Proto-Oncogene Proteins c-akt
- RNA, Messenger/analysis
- RNA, Small Interfering/pharmacology
- Rats
- Rats, Wistar
- Receptors, Lysosphingolipid/deficiency
- Receptors, Lysosphingolipid/genetics
- Receptors, Lysosphingolipid/physiology
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Sphingosine/analogs & derivatives
- Sphingosine/pharmacology
- rho-Associated Kinases
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Affiliation(s)
- C Jaillard
- Biologie des Interactions Neurones/Glie, Institut National de la Santé et de la Recherche Médicale and Université Pierre et Marie Curie, Unité Mixte de Recherche 711, Hôpital de la Salpêtrière, F-75651 Paris, France
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19
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Abstract
Lysophosphatidic acid (LPA) elicits diverse cellular responses through cell surface LPA receptors in nervous system-derived cells and cell lines. The developing nervous system is one of the major loci for LPA receptor expression. Recent studies have also revealed that metabolic pathways of LPA are present in the nervous system. A growing body of literature suggests a crucial role for LPA in neuronal development processes, including neurogenesis, neuronal migration, neuritogenesis, and myelination.
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Affiliation(s)
- Nobuyuki Fukushima
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, N15W7, Kita-ku, Sapporo 060-8638, Japan
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20
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Dawson J, Hotchin N, Lax S, Rumsby M. Lysophosphatidic acid induces process retraction in CG-4 line oligodendrocytes and oligodendrocyte precursor cells but not in differentiated oligodendrocytes. J Neurochem 2004; 87:947-57. [PMID: 14622125 DOI: 10.1046/j.1471-4159.2003.02056.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Lysophosphatidic acid is a growth factor-like signalling phospholipid. We demonstrate here that lysophosphatidic acid induces process retraction in central glia-4 cells and oligodendrocyte precursors. This lysophosphatidic acid effect is rapid and concentration-dependent and results in cell rounding. It is inhibited by pre-treatment of cells with C3 exoenzyme, a specific inhibitor of Rho, or with Y-27632, a specific inhibitor of ROCK, a downstream kinase of Rho. Processes of differentiated central glia-4 oligodendrocytes were insensitive to lysophosphatidic acid treatment but cell bodies became phase dark, indicating cell spreading on the poly-l-lysine substratum. RT-PCR and Western blot analyses indicate that oligodendrocyte precursors and mature oligodendrocytes express mRNA and protein for LPA1, one of several LPA receptors. Thus lysophosphatidic acid may be signalling to Rho and stimulating actomyosin contraction in precursor oligodendrocytes by this family of receptors. The results show that lysophosphatidic acid signalling pathways influence retraction of processes in oligodendrocyte precursors but that this effect changes as oligodendrocytes differentiate.
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Affiliation(s)
- John Dawson
- Department of Biology, University of York, York, UK.
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21
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Charrier E, Reibel S, Rogemond V, Aguera M, Thomasset N, Honnorat J. Collapsin response mediator proteins (CRMPs): involvement in nervous system development and adult neurodegenerative disorders. Mol Neurobiol 2003; 28:51-64. [PMID: 14514985 DOI: 10.1385/mn:28:1:51] [Citation(s) in RCA: 225] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2003] [Accepted: 03/26/2003] [Indexed: 11/11/2022]
Abstract
The members of the collapsin response mediator protein (CRMP) family-five cytosolic phosphoproteins -are highly expressed throughout brain development. The first member to be cloned, CRMP2, was identified as an intracellular messenger required for the growth cone-collapse induced by semaphorin 3A (Sema3A). A rapidly expanding body of study indicates that the functions of CRMPs are not solely limited to the signaling transduction of the Sema3A guidance cue. They are probably involved in multiple cellular and molecular events involved in apoptosis/proliferation, cell migration, and differentiation. In the adult brain, the expression of CRMPs is dramatically downregulated. However, they remain expressed in structures that retain their capacity for differentiation and plasticity and also in a subpopulation of oligodendrocytes (CRMP2 and CRMP5). Moreover, the expression of CRMPs is altered in neurodegenerative diseases, and these proteins may be of key importance in the physiopathology of the adult nervous system.
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Affiliation(s)
- Emmanuelle Charrier
- Institut National de la Santé et de la Recherche Médicale U 433, Hôpital Neurologique, 59 Bd Pinel, 69003 Lyon, France
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22
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Yu N, Lariosa-Willingham KD, Lin FF, Webb M, Rao TS. Characterization of lysophosphatidic acid and sphingosine-1-phosphate-mediated signal transduction in rat cortical oligodendrocytes. Glia 2003; 45:17-27. [PMID: 14648542 DOI: 10.1002/glia.10297] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) have been proposed to play a key role in oligodendrocyte maturation and myelinogenesis. In this study, we examined lysophospholipid receptor gene expression in differentiated rat oligodendrocyte cultures and signaling downstream of lysophospholipid receptor activation by LPA and S1P. Differentiated oligodendrocytes express mRNAs encoding lysophospholipid receptors with the relative abundance of lpa1>s1p5>s1p1=s1p2=lpa3>s1p3. LPA and S1P transiently increased phosphorylation of extracellular signal-regulated kinase (ERK) with EC50 values of 956 and 168 nM, respectively. LPA- and S1P-induced ERK phosphorylation was dependent on the activation of mitogen-activated protein kinase (MAPK), phospholipase C (PLC), and protein kinase C (PKC), but was insensitive to pertussis toxin (PTX). LPA increased intracellular calcium levels in oligodendrocytes and these increases were partially blocked by a PLC inhibitor but not by PTX. In contrast, S1P was not found to induce measurable changes of intracellular calcium. These results taken together suggest that lysophospholipid receptor activation involves receptor coupling to heterotrimeric Gq subunits with consequent activation of PLC, PKC, and MAPK pathways leading to ERK phosphorylation.
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Affiliation(s)
- Naichen Yu
- Molecular Neuroscience, Merck Research Laboratories, San Diego, California 92121, USA.
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23
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Abstract
The physiological and pathological importance of lysophosphatidic acid (LPA) in the nervous system is underscored by its presence, as well as the expression of its receptors in neural tissues. In fact, LPA produces responses in a broad range of cell types related to the function of the nervous system. These cell types include neural cell lines, neural progenitors, primary neurons, oligodendrocytes, Schwann cells, astrocytes, microglia, and brain endothelial cells. LPA-induced cell type-specific effects include changes in cell morphology, promotion of cell proliferation and cell survival, induction of cell death, changes in ion conductance and Ca2+ mobilization, induction of pain transmission, and stimulation of vasoconstriction. These effects are mediated through a number of G protein-coupled LPA receptors that activate various downstream signaling cascades. This review provides a current summary of LPA-induced effects in neural cells in vitro or in vivo in combination with our current understanding of the signaling pathways responsible for these effects.
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Affiliation(s)
- Xiaoqin Ye
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0636, USA
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24
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Abstract
Lysophosphatidic acid (LPA), a growth factor-like lysophospholipid, induces diverse cellular responses. The identification of the first LPA receptor gene, through studies of neuroproliferative regions within the embryonic cerebral cortex, has led to the classification of a family of at least eight lysophospholipid receptors with diverse roles in organismal development and function. A growing body of literature has identified roles for LPA signaling under physiological and pathological conditions, particularly within the developing nervous system. Here the authors review features of the LPA receptor family and cellular responses of nervous system-derived cells, and discuss developmental and pathological roles for LPA signaling in the nervous system.
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Affiliation(s)
- Nobuyuki Fukushima
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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25
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Möller T, Contos JJ, Musante DB, Chun J, Ransom BR. Expression and function of lysophosphatidic acid receptors in cultured rodent microglial cells. J Biol Chem 2001; 276:25946-52. [PMID: 11340076 DOI: 10.1074/jbc.m102691200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Microglia are the resident tissue macrophages of the central nervous system. They are rapidly activated by a variety of insults; and recently, receptors linked to cytoplasmic Ca(2+) signals have been implicated in such events. One potential class of receptors are those recognizing lysophosphatidic acid (LPA). LPA is a phospholipid signaling molecule that has been shown to cause multiple cellular responses, including increases in cytoplasmic calcium. We examined whether any of the known LPA receptor genes (lp(A1)/Edg2, lp(A2)/Edg4, and lp(A3)/Edg7) are expressed by cultured mouse or rat microglia. Reverse transcriptase-polymerase chain reaction indicated that mouse microglia predominantly expressed the lp(A1) gene, whereas rat microglia predominantly expressed lp(A3). Although LPA induced increases in the cytoplasmic Ca(2+) concentration in both microglial preparations, the responses differed substantially. The Ca(2+) signal in rat microglia occurred primarily through Ca(2+) influx via the plasma membrane, whereas the Ca(2+) signal in mouse microglia was due to release from intracellular stores. Only at high concentrations was an additional influx component recruited. Additionally, LPA induced increased metabolic activity in mouse (but not rat) microglial cells. Our findings provide evidence for functional LPA receptors on microglia. Thus, LPA might play an important role as a mediator of microglial activation in response to central nervous system injury.
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Affiliation(s)
- T Möller
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington 98195, USA.
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26
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Abstract
Intracellular Ca2+ is the key signal that regulates the efficacy of neurotransmitter release and synaptic plasticity in neurons but is also an important second messenger involved in the signal transduction and modulation of gene expression in both excitable and non-excitable cells. Glial cells, including cells of oligodendroglial (OLG) lineage, are capable of responding to extracellular stimuli via changes in the intracellular Ca2+. This review article focuses on the mechanisms of Ca2+ signalling in cells of OLG lineage with the goal of providing the basis for understanding the relevance of receptor- and non-receptor-mediated signalling to oligodendroglial development, myelination, and demyelination. Conclusions to date indicate that cells of OLG lineage exhibit remarkable plasticity with regard to the expression of ion channels and receptors linked to Ca2+ signalling and that perturbation of [Ca2](i) homeostasis contributes to the pathogenesis of demyelinating diseases.
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Affiliation(s)
- B Soliven
- Department of Neurology and Comm. on Neurobiology, The Brain Research Institute, University of Chicago, 5841 S. Maryland, Chicago, IL 60637, USA.
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27
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Hooks SB, Santos WL, Im DS, Heise CE, Macdonald TL, Lynch KR. Lysophosphatidic acid-induced mitogenesis is regulated by lipid phosphate phosphatases and is Edg-receptor independent. J Biol Chem 2001; 276:4611-21. [PMID: 11042183 DOI: 10.1074/jbc.m007782200] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lysophosphatidic acid (LPA) is an extracellular signaling mediator with a broad range of cellular responses. Three G-protein-coupled receptors (Edg-2, -4, and -7) have been identified as receptors for LPA. In this study, the ectophosphatase lipid phosphate phosphatase 1 (LPP1) has been shown to down-regulate LPA-mediated mitogenesis. Furthermore, using degradation-resistant phosphonate analogs of LPA and stereoselective agonists of the Edg receptors we have demonstrated that the mitogenic and platelet aggregation responses to LPA are independent of Edg-2, -4, and -7. Specifically, we found that LPA degradation is insufficient to account for the decrease in LPA potency in mitogenic assays, and the stereoselectivity observed at the Edg receptors is not reflected in mitogenesis. Additionally, RH7777 cells, which are devoid of Edg-2, -4, and -7 receptor mRNA, have a mitogenic response to LPA and LPA analogs. Finally, we have determined that the ligand selectivity of the platelet aggregation response is consistent with that of mitogenesis, but not with Edg-2, -4, and -7.
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Affiliation(s)
- S B Hooks
- Departments of Biochemistry, Chemistry, and Pharmacology, University of Virginia Health Sciences Center, Charlotte, VA 22908, USA.
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