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Forston MD, Wei GZ, Chariker JH, Stephenson T, Andres K, Glover C, Rouchka EC, Whittemore SR, Hetman M. Enhanced oxidative phosphorylation, re-organized intracellular signaling, and epigenetic de-silencing as revealed by oligodendrocyte translatome analysis after contusive spinal cord injury. Sci Rep 2023; 13:21254. [PMID: 38040794 PMCID: PMC10692148 DOI: 10.1038/s41598-023-48425-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 11/27/2023] [Indexed: 12/03/2023] Open
Abstract
Reducing the loss of oligodendrocytes (OLs) is a major goal for neuroprotection after spinal cord injury (SCI). Therefore, the OL translatome was determined in Ribotag:Plp1-CreERT2 mice at 2, 10, and 42 days after moderate contusive T9 SCI. At 2 and 42 days, mitochondrial respiration- or actin cytoskeleton/cell junction/cell adhesion mRNAs were upregulated or downregulated, respectively. The latter effect suggests myelin sheath loss/morphological simplification which is consistent with downregulation of cholesterol biosynthesis transcripts on days 10 and 42. Various regulators of pro-survival-, cell death-, and/or oxidative stress response pathways showed peak expression acutely, on day 2. Many acutely upregulated OL genes are part of the repressive SUZ12/PRC2 operon suggesting that epigenetic de-silencing contributes to SCI effects on OL gene expression. Acute OL upregulation of the iron oxidoreductase Steap3 was confirmed at the protein level and replicated in cultured OLs treated with the mitochondrial uncoupler FCCP. Hence, STEAP3 upregulation may mark mitochondrial dysfunction. Taken together, in SCI-challenged OLs, acute and subchronic enhancement of mitochondrial respiration may be driven by axonal loss and subsequent myelin sheath degeneration. Acutely, the OL switch to oxidative phosphorylation may lead to oxidative stress that is further amplified by upregulation of such enzymes as STEAP3.
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Affiliation(s)
- Michael D Forston
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - George Z Wei
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- MD/PhD Program, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Julia H Chariker
- Kentucky IDeA Networks of Biomedical Research Excellence (KY INBRE) Bioinformatics Core, University of Louisville, Louisville, KY, 40202, USA
- Neuroscience Training, University Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Tyler Stephenson
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Kariena Andres
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Charles Glover
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Eric C Rouchka
- Kentucky IDeA Networks of Biomedical Research Excellence (KY INBRE) Bioinformatics Core, University of Louisville, Louisville, KY, 40202, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Scott R Whittemore
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
- MD/PhD Program, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Michal Hetman
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY, 40202, USA.
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA.
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA.
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, KY, 40202, USA.
- MD/PhD Program, University of Louisville School of Medicine, Louisville, KY, 40202, USA.
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2
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Forston MD, Wei G, Chariker JH, Stephenson T, Andres K, Glover C, Rouchka EC, Whittemore SR, Hetman M. Enhanced oxidative phosphorylation, re-organized intracellular signaling, and epigenetic de-silencing as revealed by oligodendrocyte translatome analysis after contusive spinal cord injury. RESEARCH SQUARE 2023:rs.3.rs-3164618. [PMID: 37546871 PMCID: PMC10402259 DOI: 10.21203/rs.3.rs-3164618/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Reducing the loss of oligodendrocytes (OLs) is a major goal for neuroprotection after spinal cord injury (SCI). Therefore, the OL translatome was determined in Ribotag:Plp1-CreERT2 mice at 2, 10, and 42 days after moderate contusive T9 SCI. At 2 and 42 days, mitochondrial respiration- or actin cytoskeleton/cell junction/cell adhesion mRNAs were upregulated or downregulated, respectively. The latter effect suggests myelin sheath loss/morphological simplification which is consistent with downregulation of cholesterol biosynthesis transcripts on days 10 and 42. Various regulators of pro-survival-, cell death-, and/or oxidative stress response pathways showed peak expression acutely, on day 2. Many acutely upregulated OL genes are part of the repressive SUZ12/PRC2 operon suggesting that epigenetic de-silencing contributes to SCI effects on OL gene expression. Acute OL upregulation of the iron oxidoreductase Steap3 was confirmed at the protein level and replicated in cultured OLs treated with the mitochondrial uncoupler FCCP. Hence, STEAP3 upregulation may mark mitochondrial dysfunction. Taken together, in SCI-challenged OLs, acute and subchronic enhancement of mitochondrial respiration may be driven by axonal loss and subsequent myelin sheath degeneration. Acutely, the OL switch to oxidative phosphorylation may lead to oxidative stress that is further amplified by upregulation of such enzymes as STEAP3.
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Affiliation(s)
| | - George Wei
- University of Louisville School of Medicine
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3
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Rivera AD, Pieropan F, Williams G, Calzolari F, Butt AM, Azim K. Drug connectivity mapping and functional analysis reveal therapeutic small molecules that differentially modulate myelination. Biomed Pharmacother 2022; 145:112436. [PMID: 34813998 PMCID: PMC8664715 DOI: 10.1016/j.biopha.2021.112436] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/29/2021] [Accepted: 11/12/2021] [Indexed: 12/30/2022] Open
Abstract
Disruption or loss of oligodendrocytes (OLs) and myelin has devastating effects on CNS function and integrity, which occur in diverse neurological disorders, including Multiple Sclerosis (MS), Alzheimer's disease and neuropsychiatric disorders. Hence, there is a need to develop new therapies that promote oligodendrocyte regeneration and myelin repair. A promising approach is drug repurposing, but most agents have potentially contrasting biological actions depending on the cellular context and their dose-dependent effects on intracellular pathways. Here, we have used a combined systems biology and neurobiological approach to identify compounds that exert positive and negative effects on oligodendroglia, depending on concentration. Notably, next generation pharmacogenomic analysis identified the PI3K/Akt modulator LY294002 as the most highly ranked small molecule with both pro- and anti-oligodendroglial concentration-dependent effects. We validated these in silico findings using multidisciplinary approaches to reveal a profoundly bipartite effect of LY294002 on the generation of OPCs and their differentiation into myelinating oligodendrocytes in both postnatal and adult contexts. Finally, we employed transcriptional profiling and signalling pathway activity assays to determine cell-specific mechanisms of action of LY294002 on oligodendrocytes and resolve optimal in vivo conditions required to promote myelin repair. These results demonstrate the power of multidisciplinary strategies in determining the therapeutic potential of small molecules in neurodegenerative disorders.
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Affiliation(s)
- A D Rivera
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St Michael's Building, White Swan Road, PO1 2DT Portsmouth, UK; Section of Human Anatomy, Department of Neuroscience, University of Padua, Padua, Italy.
| | - F Pieropan
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St Michael's Building, White Swan Road, PO1 2DT Portsmouth, UK
| | - G Williams
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London, UK
| | - F Calzolari
- Research Group Adult Neurogenesis & Cellular Reprogramming Institute of Physiological Chemistry, University Medical Center, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 19, 55128 Mainz, Germany
| | - A M Butt
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St Michael's Building, White Swan Road, PO1 2DT Portsmouth, UK
| | - K Azim
- Department of Neurology, Neuroregeneration, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany.
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4
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Kang M, Yao Y. Laminin regulates oligodendrocyte development and myelination. Glia 2021; 70:414-429. [PMID: 34773273 DOI: 10.1002/glia.24117] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 11/08/2022]
Abstract
Oligodendrocytes are the cells that myelinate axons and provide trophic support to neurons in the CNS. Their dysfunction has been associated with a group of disorders known as demyelinating diseases, such as multiple sclerosis. Oligodendrocytes are derived from oligodendrocyte precursor cells, which differentiate into premyelinating oligodendrocytes and eventually mature oligodendrocytes. The development and function of oligodendrocytes are tightly regulated by a variety of molecules, including laminin, a major protein of the extracellular matrix. Accumulating evidence suggests that laminin actively regulates every aspect of oligodendrocyte biology, including survival, migration, proliferation, differentiation, and myelination. How can laminin exert such diverse functions in oligodendrocytes? It is speculated that the distinct laminin isoforms, laminin receptors, and/or key signaling molecules expressed in oligodendrocytes at different developmental stages are the reasons. Understanding molecular targets and signaling pathways unique to each aspect of oligodendrocyte biology will enable more accurate manipulation of oligodendrocyte development and function, which may have implications in the therapies of demyelinating diseases. Here in this review, we first introduce oligodendrocyte biology, followed by the expression of laminin and laminin receptors in oligodendrocytes and other CNS cells. Next, the functions of laminin in oligodendrocyte biology, including survival, migration, proliferation, differentiation, and myelination, are discussed in detail. Last, key questions and challenges in the field are discussed. By providing a comprehensive review on laminin's roles in OL lineage cells, we hope to stimulate novel hypotheses and encourage new research in the field.
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Affiliation(s)
- Minkyung Kang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Yao Yao
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
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Dowsett GKC, Lam BYH, Tadross JA, Cimino I, Rimmington D, Coll AP, Polex-Wolf J, Knudsen LB, Pyke C, Yeo GSH. A survey of the mouse hindbrain in the fed and fasted states using single-nucleus RNA sequencing. Mol Metab 2021; 53:101240. [PMID: 33962048 PMCID: PMC8170503 DOI: 10.1016/j.molmet.2021.101240] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/17/2021] [Accepted: 04/22/2021] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE The area postrema (AP) and nucleus tractus solitarius (NTS) located in the hindbrain are key nuclei that sense and integrate peripheral nutritional signals and consequently regulate feeding behaviour. While single-cell transcriptomics have been used in mice to reveal the gene expression profile and heterogeneity of key hypothalamic populations, similar in-depth studies have not yet been performed in the hindbrain. METHODS Using single-nucleus RNA sequencing, we provide a detailed survey of 16,034 cells within the AP and NTS of mice in the fed and fasted states. RESULTS Of these, 8,910 were neurons that group into 30 clusters, with 4,289 from mice fed ad libitum and 4,621 from overnight fasted mice. A total of 7,124 nuclei were from non-neuronal cells, including oligodendrocytes, astrocytes, and microglia. Interestingly, we identified that the oligodendrocyte population was particularly transcriptionally sensitive to an overnight fast. The receptors GLP1R, GIPR, GFRAL, and CALCR, which bind GLP1, GIP, GDF15, and amylin, respectively, are all expressed in the hindbrain and are major targets for anti-obesity therapeutics. We characterise the transcriptomes of these four populations and show that their gene expression profiles are not dramatically altered by an overnight fast. Notably, we find that roughly half of cells that express GIPR are oligodendrocytes. Additionally, we profile POMC-expressing neurons within the hindbrain and demonstrate that 84% of POMC neurons express either PCSK1, PSCK2, or both, implying that melanocortin peptides are likely produced by these neurons. CONCLUSION We provide a detailed single-cell level characterisation of AP and NTS cells expressing receptors for key anti-obesity drugs that are either already approved for human use or in clinical trials. This resource will help delineate the mechanisms underlying the effectiveness of these compounds and also prove useful in the continued search for other novel therapeutic targets.
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Affiliation(s)
- Georgina K C Dowsett
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - Brian Y H Lam
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - John A Tadross
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK; Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK.
| | - Irene Cimino
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - Debra Rimmington
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - Anthony P Coll
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | | | | | - Charles Pyke
- Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark.
| | - Giles S H Yeo
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
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Rodrigues RS, Lourenço DM, Paulo SL, Mateus JM, Ferreira MF, Mouro FM, Moreira JB, Ribeiro FF, Sebastião AM, Xapelli S. Cannabinoid Actions on Neural Stem Cells: Implications for Pathophysiology. Molecules 2019; 24:E1350. [PMID: 30959794 PMCID: PMC6480122 DOI: 10.3390/molecules24071350] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/01/2019] [Accepted: 04/03/2019] [Indexed: 02/06/2023] Open
Abstract
With the increase of life expectancy, neurodegenerative disorders are becoming not only a health but also a social burden worldwide. However, due to the multitude of pathophysiological disease states, current treatments fail to meet the desired outcomes. Therefore, there is a need for new therapeutic strategies focusing on more integrated, personalized and effective approaches. The prospect of using neural stem cells (NSC) as regenerative therapies is very promising, however several issues still need to be addressed. In particular, the potential actions of pharmacological agents used to modulate NSC activity are highly relevant. With the ongoing discussion of cannabinoid usage for medical purposes and reports drawing attention to the effects of cannabinoids on NSC regulation, there is an enormous, and yet, uncovered potential for cannabinoids as treatment options for several neurological disorders, specifically when combined with stem cell therapy. In this manuscript, we review in detail how cannabinoids act as potent regulators of NSC biology and their potential to modulate several neurogenic features in the context of pathophysiology.
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Affiliation(s)
- Rui S Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Diogo M Lourenço
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Sara L Paulo
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Joana M Mateus
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Miguel F Ferreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Francisco M Mouro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - João B Moreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Filipa F Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
| | - Sara Xapelli
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028 Lisboa, Portugal.
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Ilyasov AA, Milligan CE, Pharr EP, Howlett AC. The Endocannabinoid System and Oligodendrocytes in Health and Disease. Front Neurosci 2018; 12:733. [PMID: 30416422 PMCID: PMC6214135 DOI: 10.3389/fnins.2018.00733] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 09/24/2018] [Indexed: 12/22/2022] Open
Abstract
Cannabinoid-based interventions are being explored for central nervous system (CNS) pathologies such as neurodegeneration, demyelination, epilepsy, stroke, and trauma. As these disease states involve dysregulation of myelin integrity and/or remyelination, it is important to consider effects of the endocannabinoid system on oligodendrocytes and their precursors. In this review, we examine research reports on the effects of the endocannabinoid system (ECS) components on oligodendrocytes and their precursors, with a focus on therapeutic implications. Cannabinoid ligands and modulators of the endocannabinoid system promote cell signaling in oligodendrocyte precursor survival, proliferation, migration and differentiation, and mature oligodendrocyte survival and myelination. Agonist stimulation of oligodendrocyte precursor cells (OPCs) at both CB1 and CB2 receptors counter apoptotic processes via Akt/PI3K, and promote proliferation via Akt/mTOR and ERK pathways. CB1 receptors in radial glia promote proliferation and conversion to progenitors fated to become oligodendroglia, whereas CB2 receptors promote OPC migration in neonatal development. OPCs produce 2-arachidonoylglycerol (2-AG), stimulating cannabinoid receptor-mediated ERK pathways responsible for differentiation to arborized, myelin basic protein (MBP)-producing oligodendrocytes. In cell culture models of excitotoxicity, increased reactive oxygen species, and depolarization-dependent calcium influx, CB1 agonists improved viability of oligodendrocytes. In transient and permanent middle cerebral artery occlusion models of anoxic stroke, WIN55212-2 increased OPC proliferation and maturation to oligodendroglia, thereby reducing cerebral tissue damage. In several models of rodent encephalomyelitis, chronic treatment with cannabinoid agonists ameliorated the damage by promoting OPC survival and oligodendrocyte function. Pharmacotherapeutic strategies based upon ECS and oligodendrocyte production and survival should be considered.
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Affiliation(s)
- Alexander A Ilyasov
- Graduate Program in Neuroscience, Wake Forest School of Medicine, Winston Salem, NC, United States.,Department of Physiology and Pharmacology and Center for Research on Substance Use and Addiction, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Carolanne E Milligan
- Graduate Program in Neuroscience, Wake Forest School of Medicine, Winston Salem, NC, United States.,Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Emily P Pharr
- Graduate Program in Neuroscience, Wake Forest School of Medicine, Winston Salem, NC, United States.,Department of Neurology and Comprehensive Multiple Sclerosis Center, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Allyn C Howlett
- Graduate Program in Neuroscience, Wake Forest School of Medicine, Winston Salem, NC, United States.,Department of Physiology and Pharmacology and Center for Research on Substance Use and Addiction, Wake Forest School of Medicine, Winston-Salem, NC, United States
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8
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CK2 inhibition protects white matter from ischemic injury. Neurosci Lett 2018; 687:37-42. [PMID: 30125643 DOI: 10.1016/j.neulet.2018.08.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 11/21/2022]
Abstract
Strokes occur predominantly in the elderly and white matter (WM) is injured in most strokes, contributing to the disability associated with clinical deficits. Casein kinase 2 (CK2) is expressed in neuronal cells and was reported to be neuroprotective during cerebral ischemia. Recently, we reported that CK2 is abundantly expressed by glial cells and myelin. However, in contrast to its role in cerebral (gray matter) ischemia, CK2 activation during ischemia mediated WM injury via the CDK5 and AKT/GSK3β signaling pathways (Bastian et al., 2018). Subsequently, CK2 inhibition using the small molecule inhibitor CX-4945 correlated with preservation of oligodendrocytes as well as conservation of axon structure and axonal mitochondria, leading to improved functional recovery. Notably, CK2 inhibition promoted WM function when applied before or after ischemic injury by differentially regulating the CDK5 and AKT/GSK3β pathways. Specifically, blockade of the active conformation of AKT conferred post-ischemic protection to young, aging, and old WM, suggesting a common therapeutic target across age groups. CK2 inhibitors are currently being used in clinical trials for cancer patients; therefore, it is important to consider the potential benefits of CK2 inhibitors during an ischemic attack.
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9
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Azim K, Angonin D, Marcy G, Pieropan F, Rivera A, Donega V, Cantù C, Williams G, Berninger B, Butt AM, Raineteau O. Pharmacogenomic identification of small molecules for lineage specific manipulation of subventricular zone germinal activity. PLoS Biol 2017; 15:e2000698. [PMID: 28350803 PMCID: PMC5370089 DOI: 10.1371/journal.pbio.2000698] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 02/21/2017] [Indexed: 11/18/2022] Open
Abstract
Strategies for promoting neural regeneration are hindered by the difficulty of manipulating desired neural fates in the brain without complex genetic methods. The subventricular zone (SVZ) is the largest germinal zone of the forebrain and is responsible for the lifelong generation of interneuron subtypes and oligodendrocytes. Here, we have performed a bioinformatics analysis of the transcriptome of dorsal and lateral SVZ in early postnatal mice, including neural stem cells (NSCs) and their immediate progenies, which generate distinct neural lineages. We identified multiple signaling pathways that trigger distinct downstream transcriptional networks to regulate the diversity of neural cells originating from the SVZ. Next, we used a novel in silico genomic analysis, searchable platform-independent expression database/connectivity map (SPIED/CMAP), to generate a catalogue of small molecules that can be used to manipulate SVZ microdomain-specific lineages. Finally, we demonstrate that compounds identified in this analysis promote the generation of specific cell lineages from NSCs in vivo, during postnatal life and adulthood, as well as in regenerative contexts. This study unravels new strategies for using small bioactive molecules to direct germinal activity in the SVZ, which has therapeutic potential in neurodegenerative diseases. The subventricular zone (SVZ) is the largest germinal zone of the postnatal and adult brain. It contains neural stem cells (NSCs) that give rise to neurons and oligodendrocytes (OLs) in a region-specific manner. Here, we use a bioinformatics approach to identify multiple signaling pathways that regulate the diversity of cell lineages that originate from different subregions of the SVZ. We further use a computational-based drug-discovery strategy to identify a catalogue of small molecules that can be used to manipulate the regionalization of the SVZ. We provide proof that, by administration of small molecules in vivo, it is possible to promote the specific generation of neurons and OLs from NSCs in both the postnatal and adult brain, as well as in regenerative contexts after lesion. This study unravels novel strategies for using small bioactive molecules to direct germinal activity in the SVZ, which has therapeutic potential in neurodegenerative diseases.
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Affiliation(s)
- Kasum Azim
- Brain Research Institute, University of Zürich/ETHZ, Zürich, Switzerland
- Adult Neurogenesis and Cellular Reprogramming, Institute of Physiological Chemistry, University Medical Centre of the Johannes Gutenberg University Mainz, Germany
- Focus Program Translational Neuroscience, Johannes Gutenberg University Mainz, Germany
- * E-mail: (KA); (OR); (AMB)
| | - Diane Angonin
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Guillaume Marcy
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Francesca Pieropan
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Andrea Rivera
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Vanessa Donega
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | | | - Gareth Williams
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London, United Kingdom
| | - Benedikt Berninger
- Adult Neurogenesis and Cellular Reprogramming, Institute of Physiological Chemistry, University Medical Centre of the Johannes Gutenberg University Mainz, Germany
- Focus Program Translational Neuroscience, Johannes Gutenberg University Mainz, Germany
| | - Arthur M. Butt
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
- * E-mail: (KA); (OR); (AMB)
| | - Olivier Raineteau
- Brain Research Institute, University of Zürich/ETHZ, Zürich, Switzerland
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
- * E-mail: (KA); (OR); (AMB)
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Delaney CL, Feldman EL. Review ■ : Insulin-like Growth Factor-I and Apoptosis in Glial Cell Biology. Neuroscientist 2016. [DOI: 10.1177/107385840000600112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Insulin-like growth factor-I (IGF-I) is a potent trophic factor capable of promoting both survival and differentiation of neurons and glia. This review examines the role of IGF-I and apoptosis in oligodendrocyte and Schwann cell biology in vitro and in vivo. Apoptosis is an essential element of development, homeostasis, and disease. IGF-I protects oligodendrocytes and Schwann cells from apoptosis during development and after apoptotic stimuli. Transgenic mouse models, which ablate or increase expression of IGF-I, have abnormal oligodendrocytes and myelin formation. A more thorough understanding of the protective mechanism of IGF-I in oligodendrocytes and Schwann cells will aid in its precise application in treating a variety of neurologic disorders. NEUROSCIENTIST 6:39-47, 2000
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Affiliation(s)
| | - Eva L. Feldman
- Department of Neurology University of Michigan Ann Arbor, Michigan
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11
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Dukala DE, Soliven B. S1P1deletion in oligodendroglial lineage cells: Effect on differentiation and myelination. Glia 2015; 64:570-82. [DOI: 10.1002/glia.22949] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 10/14/2015] [Accepted: 11/17/2015] [Indexed: 01/21/2023]
Affiliation(s)
- Danuta E. Dukala
- Department of Neurology; the University of Chicago; Chicago Illinois
| | - Betty Soliven
- Department of Neurology; the University of Chicago; Chicago Illinois
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12
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Carvalho LA, Vitorino LC, Guimarães RPM, Allodi S, de Melo Reis RA, Cavalcante LA. Selective stimulatory action of olfactory ensheathing glia-conditioned medium on oligodendroglial differentiation, with additional reference to signaling mechanisms. Biochem Biophys Res Commun 2014; 449:338-43. [PMID: 24853803 DOI: 10.1016/j.bbrc.2014.05.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 05/13/2014] [Indexed: 12/14/2022]
Abstract
We examined the effects of conditioned medium from olfactory ensheathing glia (OEGCM) on the differentiation of oligodendrocytes in mixed cultures of early postnatal hippocampi. Differentiation was judged from the numerical density (ND) of cells immunoreactive to 2'3' cyclic nucleotide 3'phosphodiesterase (CNPase) and O4 antibodies. NDs increased according to inverted-U dose-response curves, particularly for CNPase+ cells (9-fold at optimal dilution) and these changes were blocked by inhibitors of ERK1, p38-MAPK, and PI3K. Our results raise the possibility that OEG secreted factor(s) may counteract demyelination induced by trauma, neurodegenerative diseases, and advanced age, and should stimulate novel methods to deliver these factors and/or potentiating chemicals.
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Affiliation(s)
- Litia A Carvalho
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Fisiologia), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Biofísica), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil
| | - Louise C Vitorino
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Biofísica), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil
| | - Roberta P M Guimarães
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Biofísica), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil
| | - Silvana Allodi
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Fisiologia), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Biofísica), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil
| | - Ricardo A de Melo Reis
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Fisiologia), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Biofísica), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil
| | - Leny A Cavalcante
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Fisiologia), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil.
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Brazel CY, Alaythan AA, Felling RJ, Calderon F, Levison SW. Molecular features of neural stem cells enable their enrichment using pharmacological inhibitors of survival-promoting kinases. J Neurochem 2013; 128:376-90. [PMID: 24032666 DOI: 10.1111/jnc.12447] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 09/05/2013] [Accepted: 09/10/2013] [Indexed: 11/28/2022]
Abstract
Isolating a pure population of neural stem cells (NSCs) has been difficult since no exclusive surface markers have been identified for panning or FACS purification. Moreover, additional refinements for maintaining NSCs in culture are required, since NSCs generate a variety of neural precursors (NPs) as they proliferate. Here, we demonstrate that post-natal rat NPs express low levels of pro-apoptotic molecules and resist phosphatidylinositol 3'OH kinase and extracellular regulated kinase 1/2 inhibition as compared to late oligodendrocyte progenitors. Furthermore, maintaining subventricular zone precursors in LY294002 and PD98059, inhibitors of PI3K and ERK1/2 signaling, eliminated lineage-restricted precursors as revealed by enrichment for Nestin(+)/SOX-2(+) cells. The cells that survived formed neurospheres and 89% of these neurospheres were tripotential, generating neurons, astrocytes, and oligodendrocytes. Without this enrichment step, less than 50% of the NPs were Nestin(+)/SOX-2(+) and 42% of the neurospheres were tripotential. In addition, neurospheres enriched using this procedure produced 3-times more secondary neurospheres, supporting the conclusion that this procedure enriches for NSCs. A number of genes that enhance survival were more highly expressed in neurospheres compared to late oligodendrocyte progenitors. Altogether, these studies demonstrate that primitive neural precursors can be enriched using a relatively simple and inexpensive means that will facilitate cell replacement strategies using stem cells as well as other studies whose goal is to reveal the fundamental properties of primitive neural precursors.
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Affiliation(s)
- Christine Y Brazel
- Department of Neurology and Neurosciences, Rutgers University-New Jersey Medical School, Newark, New Jersey, USA
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14
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O’Kusky J, Ye P. Neurodevelopmental effects of insulin-like growth factor signaling. Front Neuroendocrinol 2012; 33:230-51. [PMID: 22710100 PMCID: PMC3677055 DOI: 10.1016/j.yfrne.2012.06.002] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/09/2012] [Accepted: 06/07/2012] [Indexed: 11/28/2022]
Abstract
Insulin-like growth factor (IGF) signaling greatly impacts the development and growth of the central nervous system (CNS). IGF-I and IGF-II, two ligands of the IGF system, exert a wide variety of actions both during development and in adulthood, promoting the survival and proliferation of neural cells. The IGFs also influence the growth and maturation of neural cells, augmenting dendritic growth and spine formation, axon outgrowth, synaptogenesis, and myelination. Specific IGF actions, however, likely depend on cell type, developmental stage, and local microenvironmental milieu within the brain. Emerging research also indicates that alterations in IGF signaling likely contribute to the pathogenesis of some neurological disorders. This review summarizes experimental studies and shed light on the critical roles of IGF signaling, as well as its mechanisms, during CNS development.
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Affiliation(s)
- John O’Kusky
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada V5Z 1M9
| | - Ping Ye
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
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15
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Correa F, Gauberti M, Parcq J, Macrez R, Hommet Y, Obiang P, Hernangómez M, Montagne A, Liot G, Guaza C, Maubert E, Ali C, Vivien D, Docagne F. Tissue plasminogen activator prevents white matter damage following stroke. ACTA ACUST UNITED AC 2011; 208:1229-42. [PMID: 21576385 PMCID: PMC3173251 DOI: 10.1084/jem.20101880] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tissue plasminogen activator (tPA) is the only available treatment for acute stroke. In addition to its vascular fibrinolytic action, tPA exerts various effects within the brain, ranging from synaptic plasticity to control of cell fate. To date, the influence of tPA in the ischemic brain has only been investigated on neuronal, microglial, and endothelial fate. We addressed the mechanism of action of tPA on oligodendrocyte (OL) survival and on the extent of white matter lesions in stroke. We also investigated the impact of aging on these processes. We observed that, in parallel to reduced levels of tPA in OLs, white matter gets more susceptible to ischemia in old mice. Interestingly, tPA protects murine and human OLs from apoptosis through an unexpected cytokine-like effect by the virtue of its epidermal growth factor-like domain. When injected into aged animals, tPA, although toxic to the gray matter, rescues white matter from ischemia independently of its proteolytic activity. These studies reveal a novel mechanism of action of tPA and unveil OL as a target cell for cytokine effects of tPA in brain diseases. They show overall that tPA protects white matter from stroke-induced lesions, an effect which may contribute to the global benefit of tPA-based stroke treatment.
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Affiliation(s)
- Fernando Correa
- Institut National de la Santé et de la Recherche Médicale (INSERM), INSERM-U919, Caen Cedex, F-14074 France
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16
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Integrin signaling in oligodendrocytes and its importance in CNS myelination. JOURNAL OF SIGNAL TRANSDUCTION 2010; 2011:354091. [PMID: 21637375 PMCID: PMC3101883 DOI: 10.1155/2011/354091] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 10/28/2010] [Indexed: 12/22/2022]
Abstract
Multiple sclerosis is characterized by repeated demyelinating attacks of the central nervous system (CNS) white matter tracts. To tailor novel therapeutics to halt or reverse disease process, we require a better understanding of oligodendrocyte biology and of the molecular mechanisms that initiate myelination. Cell extrinsic mechanisms regulate CNS myelination through the interaction of extracellular matrix proteins and their transmembrane receptors. The engagement of one such receptor family, the integrins, initiates intracellular signaling cascades that lead to changes in cell phenotype. Oligodendrocytes express a diverse array of integrins, and the expression of these receptors is developmentally regulated. Integrin-mediated signaling is crucial to the proliferation, survival, and maturation of oligodendrocytes through the activation of downstream signaling pathways involved in cytoskeletal remodeling. Here, we review the current understanding of this important signaling axis and its role in oligodendrocyte biology and ultimately in the myelination of axons within the CNS.
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17
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Ye P, Hu Q, Liu H, Yan Y, D'ercole AJ. beta-catenin mediates insulin-like growth factor-I actions to promote cyclin D1 mRNA expression, cell proliferation and survival in oligodendroglial cultures. Glia 2010; 58:1031-41. [PMID: 20235220 PMCID: PMC2917840 DOI: 10.1002/glia.20984] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
By promoting cell proliferation, survival and maturation insulin-like growth factor (IGF)-I is essential to the normal growth and development of the central nervous system. It is clear that IGF-I actions are primarily mediated by the type I IGF receptor (IGF1R), and that phosphoinositide 3 (PI3)-Akt kinases and MAP kinases signal many of IGF-I-IGF1R actions in neural cells, including oligodendrocyte lineage cells. The precise downstream targets of these signaling pathways, however, remain to be defined. We studied oligodendroglial cells to determine whether beta-catenin, a molecule that is a downstream target of glycogen synthase kinase-3beta (GSK3beta) and plays a key role in the Wnt canonical signaling pathway, mediates IGF-I actions. We found that IGF-I increases beta-catenin protein abundance within an hour after IGF-I-induced phosphorylation of Akt and GSK3beta. Inhibiting the PI3-Akt pathway suppressed IGF-I-induced increases in beta-catenin and cyclin D1 mRNA, while suppression of GSK3beta activity simulated IGF-I actions. Knocking-down beta-catenin mRNA by RNA interference suppressed IGF-I-stimulated increases in the abundance of cyclin D1 mRNA, cell proliferation, and cell survival. Our data suggest that beta-catenin is an important downstream molecule in the PI3-Akt-GSK3beta pathway, and as such it mediates IGF-I upregulation of cyclin D1 mRNA and promotion of cell proliferation and survival in oligodendroglial cells.
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Affiliation(s)
- Ping Ye
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7039, USA.
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18
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Thimmaiah KN, Easton JB, Houghton PJ. Protection from rapamycin-induced apoptosis by insulin-like growth factor-I is partially dependent on protein kinase C signaling. Cancer Res 2010; 70:2000-9. [PMID: 20179209 DOI: 10.1158/0008-5472.can-09-3693] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Rapamycin-induced apoptosis in sarcoma cells is inhibited by insulin-like growth factor-I (IGF-I) through a signaling pathway independent of Ras-extracellular signal-regulated kinase 1/2 and Akt. IGF-I induces Bad phosphorylation (Ser112, Ser136, and Ser155) in a pathway involving phosphoinositide 3' kinase (PI3K) and protein kinase C (PKC; mu, epsilon, or theta) resulting in sequestering Bad from mitochondria and subsequently interacting with 14-3-3gamma in the cytosol. Gene knockdown of Bad, Bid, Akt1, Akt2, PKC-mu, PKC-epsilon, or PKC-theta was achieved by transient transfection using small interfering RNAs. Results indicate that IGF-I signaling to Bad requires activation of PI3K and PKC (mu, theta, epsilon) but not mTOR, Ras-extracellular signal-regulated kinase 1/2, protein kinase A, or p90(RSK). Wortmannin blocked the phosphorylation of PKC-mu (Ser744/Ser748), suggesting that PI3K is required for the activation of PKCs. PKCs phosphorylate Bad under in vitro conditions, and the association of phosphorylated Bad with PKC-mu or PKC-epsilon, as shown by immunoprecipitation, indicated direct involvement of PKCs in Bad phosphorylation. To confirm these results, cells overexpressing pEGFP-N1, wt-Bad, or Bad with a single site mutated (Ser112Ala; Ser136Ala; Ser155Ala), two sites mutated (Ser(112/136)Ala; Ser(112/155)Ala; Ser(136/155)Ala), or the triple mutant were tested. IGF-I protected completely against rapamycin-induced apoptosis in cells overexpressing wt-Bad and mutants having either one or two sites of phosphorylation mutated. Knockdown of Bid using small interfering RNA showed that Bid is not required for rapamycin-induced cell death. Collectively, these data suggest that IGF-I-induced phosphorylation of Bad at multiple sites via a pathway involving PI3K and PKCs is important for protecting sarcoma cells from rapamycin-induced apoptosis.
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19
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Frost EE, Zhou Z, Krasnesky K, Armstrong RC. Initiation of oligodendrocyte progenitor cell migration by a PDGF-A activated extracellular regulated kinase (ERK) signaling pathway. Neurochem Res 2008; 34:169-81. [PMID: 18512152 DOI: 10.1007/s11064-008-9748-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 05/12/2008] [Indexed: 01/27/2023]
Abstract
During CNS development, oligodendrocyte progenitor (OP) cells migrate from germinal zones to presumptive white matter tracts to generate myelinating oligodendrocytes. In vitro and in vivo studies indicate that platelet-derived growth factor-A (PDGF-A) is a potent chemoattractant for OP cells and important for normal distribution throughout the developing CNS. However, PDGF-A does not localize in concentration gradients corresponding to OP migratory pathways, as would be expected for a chemoattractant to direct migration. Therefore, the mechanism by which PDGF-A regulates OP distribution remains to be clarified. Here we show that PDGF-A induces OP migration and continuous exposure to PDGF-A is not required to maintain migration. Using pharmacological inhibitors, we show that a self-sustaining extracellular-regulated-kinase signaling pathway drives OP migration for up to 72 hours after the initial PDGF stimulus. These findings indicate PDGF-A may act to mobilize OP cells that then respond to distinct directional signals to distribute appropriately within the CNS.
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Affiliation(s)
- Emma E Frost
- Department of Pathology, University of Manitoba, JBRC401, 727 McDermot Avenue, Winnipeg, MB, Canada, R3E 3P5.
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20
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Chen CR, Young TH. The effect of gallium nitride on long-term culture induced aging of neuritic function in cerebellar granule cells. Biomaterials 2008; 29:1573-82. [DOI: 10.1016/j.biomaterials.2007.11.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Accepted: 11/26/2007] [Indexed: 10/22/2022]
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Diemer C, Schneider M, Seebach J, Quaas J, Frösner G, Schätzl HM, Gilch S. Cell type-specific cleavage of nucleocapsid protein by effector caspases during SARS coronavirus infection. J Mol Biol 2007; 376:23-34. [PMID: 18155731 PMCID: PMC7094231 DOI: 10.1016/j.jmb.2007.11.081] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2007] [Revised: 11/20/2007] [Accepted: 11/26/2007] [Indexed: 12/30/2022]
Abstract
The epidemic outbreak of severe acute respiratory syndrome (SARS) in 2003 was caused by a novel coronavirus (CoV), designated SARS-CoV. The RNA genome of SARS-CoV is complexed by the nucleocapsid protein (N) to form a helical nucleocapsid. Besides this primary function, N seems to be involved in apoptotic scenarios. We show that upon infection of Vero E6 cells with SARS-CoV, which elicits a pronounced cytopathic effect and a high viral titer, N is cleaved by caspases. In contrast, in SARS-CoV-infected Caco-2 cells, which show a moderate cytopathic effect and a low viral titer, this processing of N was not observed. To further verify these observations, we transiently expressed N in different cell lines. Caco-2 and N2a cells served as models for persistent SARS-CoV infection, whereas Vero E6 and A549 cells did as prototype cell lines lytically infected by SARS-CoV. The experiments revealed that N induces the intrinsic apoptotic pathway, resulting in processing of N at residues 400 and 403 by caspase-6 and/or caspase-3. Of note, caspase activation is highly cell type specific in SARS-CoV-infected as well as transiently transfected cells. In Caco-2 and N2a cells, almost no N-processing was detectable. In Vero E6 and A549 cells, a high proportion of N was cleaved by caspases. Moreover, we examined the subcellular localization of SARS-CoV N in these cell lines. In transfected Vero E6 and A549 cells, SARS-CoV N was localized both in the cytoplasm and nucleus, whereas in Caco-2 and N2a cells, nearly no nuclear localization was observed. In addition, our studies indicate that the nuclear localization of N is essential for its caspase-6-mediated cleavage. These data suggest a correlation among the replication cycle of SARS-CoV, subcellular localization of N, induction of apoptosis, and the subsequent activation of caspases leading to cleavage of N.
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Affiliation(s)
- Claudia Diemer
- Institute of Virology, Technical University of Munich, Trogerstr. 30, 81675 Munich, Germany
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22
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Frederick TJ, Min J, Altieri SC, Mitchell NE, Wood TL. Synergistic induction of cyclin D1 in oligodendrocyte progenitor cells by IGF-I and FGF-2 requires differential stimulation of multiple signaling pathways. Glia 2007; 55:1011-22. [PMID: 17508424 DOI: 10.1002/glia.20520] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
D-type cyclins are direct targets of extracellular signals and critical regulators of G(1) progression. Our previous data demonstrated that IGF-I and FGF-2 synergize to enhance cyclin D1 expression, cyclin E/cdk2 complex activation, and S-phase entry in OP cells. Here, we provide a mechanistic explanation for how two growth factor signaling pathways converge on a major cell cycle regulator. IGF-I and FGF-2 differentially activate signaling pathways to coordinately promote cyclin D1 expression. We show that the p44/p42 MAPK signaling pathway is essential for FGF-2 induction of cyclin D1 mRNA. In contrast, blocking the PI3-Kinase pathway results in loss of IGF-I/FGF-2 synergistic induction of cyclin D1 protein levels. Moreover, the presence of IGF-I significantly enhances nuclear localization of cyclin D1, which also requires PI3K signaling. GSK-3beta, a downstream target of the PI3K/Akt pathway, is phosphorylated in the presence of IGF-I in OPs. Consistent with a known role for GSK-3beta in cyclin D1 degradation, we show that proteasome inhibition in OPs exposed to FGF-2 increased cyclin D1 levels, equivalent to levels seen in IGF-I/FGF-2 treated cells. Thus, we provide a model for cyclin D1 coordinate regulation where FGF-2 stimulation of the MAPK pathway promotes cyclin D1 mRNA expression while IGF-I activation of the PI3K pathway inhibits proteasome degradation of cyclin D1 and enhances nuclear localization of cyclin D1.
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Affiliation(s)
- Terra J Frederick
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, Pennsylvania, USA
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Lagarde WH, Benjamin R, Heerens AT, Ye P, Cohen RI, Moats-Staats BM, D'Ercole AJ. A non-transformed oligodendrocyte precursor cell line, OL-1, facilitates studies of insulin-like growth factor-I signaling during oligodendrocyte development. Int J Dev Neurosci 2007; 25:95-105. [PMID: 17306496 PMCID: PMC2302791 DOI: 10.1016/j.ijdevneu.2006.12.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 12/19/2006] [Accepted: 12/20/2006] [Indexed: 11/20/2022] Open
Abstract
The process by which oligodendrocyte progenitors differentiate into mature oligodendrocytes is complex and incompletely understood in part because of the paucity of oligodendrocyte precursors cell lines that can be studied in culture. We have developed a non-immortalized rat oligodendrocyte precursor line, called OL-1, which behaves in a fashion consistent with developing oligodendrocytes in vivo. This OL-1 line provides a model for the study of oligodendrocyte development and offers an alternative to the CG-4 cell line. When OL-1 cells are propagated in conditioned growth media, they have morphology consistent with immature oligodendrocytes and exhibit A2B5 antigen positive and myelin basic protein-negative immunoreactivity. Withdrawal of conditioned growth media and culture in serum-free medium results in OL-1 cell maturation, manifested by a shift to myelin basic protein-positive immunoreactivity, A2B5 antigen-negative immunoreactivity, decreased NG2 mRNA expression, increased expression of proteolipid protein mRNA, and increased expression of CNP protein. In addition, the expression of proteolipid protein and its splicing variant DM-20 exhibit a pattern that is similar to brain proteolipid protein expression during development. When OL-1 cells are exposed to Insulin-like growth factor-I, there are significant increases in proteolipid protein mRNA expression (p<0.05), the number of cell processes (p<0.05), and cell number (p<0.05). Treatment with the caspase inhibitors Z-DEVD-FMK and Z-VAD-FMK (inhibitors of caspases 3, 6, 7, 8, 10 and 1, 3, 4, respectively), Insulin-like growth factor-I, or both, results in a similar increase in cell number. Because Insulin-like growth factor-I does not substantially increase the BrdU labeling of OL-1 cells, these data collectively indicate that Insulin-like growth factor-I increases OL-1 cell number predominately by promoting survival, rather than stimulating proliferation. This non-immortalized oligodendrocyte precursor cell line, therefore, exhibits behavior consistent with the in vivo development of oligodendrocytes and provides an excellent model for the study of developing oligodendrocytes.
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Affiliation(s)
- William H Lagarde
- Department of Pediatrics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7039, USA.
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24
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Albrecht PJ, Enterline JC, Cromer J, Levison SW. CNTF-Activated Astrocytes Release a Soluble Trophic Activity for Oligodendrocyte Progenitors. Neurochem Res 2006; 32:263-71. [PMID: 17004130 DOI: 10.1007/s11064-006-9151-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Accepted: 08/29/2006] [Indexed: 10/24/2022]
Abstract
CNTF (ciliary neurotrophic factor) has been suggested to be an important survival factor for oligodendrocytes; however, this effect is inconsistently obtained and myelination appears normal in CNTF null animals. On the other hand, CNTF stimulates astrocytes to produce growth and trophic factors. Therefore, we tested the hypothesis that CNTF acts indirectly through astrocytes to promote oligodendrocyte survival. We show that CNTF-stimulated astrocytes release a trophic factor(s) that leads to more than double the number of oligodendrocyte progenitor cells (OPCs) by 48 h. The trophic activity fractionates at greater than 30 kD. By contrast, OPCs grown in CNTF supplemented chemically defined medium fared no better than cells grown without CNTF. Untreated astrocytes, and CNTF- and IL-1beta -stimulated astrocytes all promoted the proliferation of OPCs to a similar extent, but only the CNTF-stimulated astrocyte conditioned media (CM) resulted in increased OPCs numbers. Cumulatively, these results confirm previous data indicating that astrocytes release potent mitogens for oligodendroglia, and demonstrate that CNTF stimulates astrocytes to release an OPC survival-promoting activity.
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Affiliation(s)
- Phillip J Albrecht
- Center for Neuropharmacolgy and Neuroscience, Albany Medical Center, Albany, NY 12208, USA
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Cui QL, Fogle E, Almazan G. Muscarinic acetylcholine receptors mediate oligodendrocyte progenitor survival through Src-like tyrosine kinases and PI3K/Akt pathways. Neurochem Int 2006; 48:383-93. [PMID: 16439036 DOI: 10.1016/j.neuint.2005.11.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 11/22/2005] [Accepted: 11/29/2005] [Indexed: 01/22/2023]
Abstract
The function of muscarinic acetylcholine receptors expressed in oligodendrocytes and in myelin has remained largely undetermined. Here we present evidence that incubation of oligodendrocyte progenitors, deprived of growth factor, with the acetylcholine analog carbachol significantly reduced cell death by apoptosis and blocked caspase-3 cleavage. This protective effect was reversed by atropine, a muscarinic acetylcholine receptor antagonist, as well as by specific inhibitors of intracellular signaling molecules, including phosphatidylinositol 3-kinase (Wortmannin and LY294002), Akt (Akt inhibitor III) and Src-like tyrosine kinases (PP2), but not by the mitogen-activated protein kinase kinase inhibitor, PD98059. Activation of Akt by carbachol was antagonized by atropine and inhibited by LY294002 and PP2. The Src-like tyrosine kinase inhibitor, PP2, also reduced carbachol stimulation of extracellular signal-regulated kinases 1/2 and cAMP-response element binding protein in a dose-dependent manner. Furthermore, carbachol increased tyrosine-phosphorylation of Fyn, a member of the Src-like tyrosine kinases. These results indicate that muscarinic acetylcholine receptors play an important role in oligodendrocyte progenitor survival through transduction pathways involving activation of Src-like tyrosine kinases and phosphatidylinositol 3-kinase/Akt.
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Affiliation(s)
- Qiao-Ling Cui
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Que., Canada
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26
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Ye P, D'Ercole AJ. Insulin-like growth factor actions during development of neural stem cells and progenitors in the central nervous system. J Neurosci Res 2006; 83:1-6. [PMID: 16294334 DOI: 10.1002/jnr.20688] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Insulin-like growth factor-I (IGF-I) plays a key role in normal development. Recent studies show that IGF-I exerts a wide variety actions in the central nervous system during development as well as in adulthood. This report reviews recent developments on IGF-I actions and its mechanisms in the central nervous system, with a focus on its actions during the development of neural stem cells and progenitors. Available data strongly indicate that IGF-I shortens the length of the cell cycle in neuron progenitors during embryonic life and has an influence on the growth of all neural cell types. The phosphatidylinositol-3 kinase/Akt and mitogen-activated protein kinase pathways seem to be the predominant mediators of IGF-I-stimulated neural cell proliferation and survival. IGF-I actions, however, likely depend on cell type, developmental stage, and microenvironmental milieu.
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Affiliation(s)
- Ping Ye
- Department of Pediatrics, The University of North Carolina at Chapel Hill, 27599-7220, USA.
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27
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Palacios N, Sánchez-Franco F, Fernández M, Sánchez I, Cacicedo L. Intracellular events mediating insulin-like growth factor I-induced oligodendrocyte development: modulation by cyclic AMP. J Neurochem 2006; 95:1091-107. [PMID: 16271046 DOI: 10.1111/j.1471-4159.2005.03419.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Insulin-like growth factor I (IGF-I) is a potent inducer of oligodendrocyte development and myelination. Although IGF-I intracellular signaling has been well described in several cell types, intracellular mechanisms for IGF-I-induced oligodendrocyte development have not been defined. By using specific inhibitors of intracellular signaling pathways, we report here that the MAPK and phosphatidylinositol 3-kinase signaling pathways are required for the full effect of IGF-I on oligodendrocyte development in primary mixed rat cerebrocortical cell cultures. The MAPK activation, but not the phosphatidylinositol 3-kinase activation, leads to phosphorylation of the cAMP response element-binding protein, which is necessary for IGF-I to induce oligodendrocyte development. cAMP, although it does not show any effect on oligodendrocyte development, has an inhibitory effect on IGF-I-induced oligodendrocyte development that is mediated by the cAMP-dependent protein kinase. Furthermore, cAMP also has an inhibitory effect on IGF-I-dependent MAPK activation. This is a cAMP-dependent protein kinase-independent effect and probably contributes to the cAMP action on IGF-I-induced oligodendrocyte development.
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Affiliation(s)
- Nuria Palacios
- Servicio de Endocrinología, Hospital Ramón y Cajal, Madrid, Spain
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Popken GJ, Dechert-Zeger M, Ye P, D'Ercole AJ. Brain Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2005; 567:187-220. [PMID: 16372399 DOI: 10.1007/0-387-26274-1_8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Affiliation(s)
- Gregory J Popken
- Division Pediatric Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, NC 27599-7039, USA
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29
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Riley JK, Carayannopoulos MO, Wyman AH, Chi M, Ratajczak CK, Moley KH. The PI3K/Akt pathway is present and functional in the preimplantation mouse embryo. Dev Biol 2005; 284:377-86. [PMID: 16005454 DOI: 10.1016/j.ydbio.2005.05.033] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 05/24/2005] [Accepted: 05/25/2005] [Indexed: 11/19/2022]
Abstract
The PI3K/Akt signal transduction pathway is a well-known mediator of growth promoting and cell survival signals. While the expression and function of this pathway have been documented during early and late stages of the reproductive process, currently, there is no evidence demonstrating either the presence or function of the PI3K/Akt pathway in murine preimplantation embryos. We found, using confocal immunofluorescent microscopy and Western blot analysis, that the p 85 and p110 subunits of PI3K and Akt are expressed from the 1-cell through the blastocyst stage of murine preimplantation embryo development. These proteins were localized predominantly at the cell surface from the 1-cell through the morula stage. At a blastocyst stage, both PI3K and Akt exhibited an apical staining pattern in the trophectoderm cells. Interestingly, phosphorylated Akt was detected throughout murine preimplantation development, and its presence at the plasma membrane is a reflection of its activation status. Inhibition of Akt activity had significant effects on the normal physiology of the blastocyst. Specifically, inhibition of this pathway resulted in a reduction in insulin-stimulated glucose uptake. In addition, inhibiting Akt activity resulted in a significant delay in blastocyst hatching, a developmental step facilitating implantation. Finally, we established the presence of this pathway in trophoblast stem (TS) cells, a potentially useful in vitro model to study this signaling cascade. Taken together, these data are the first to demonstrate the presence and function of the PI3K/Akt pathway in mammalian preimplantation embryos.
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Affiliation(s)
- Joan K Riley
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO 63110, USA
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30
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Zaka M, Rafi MA, Rao HZ, Luzi P, Wenger DA. Insulin-like growth factor-1 provides protection against psychosine-induced apoptosis in cultured mouse oligodendrocyte progenitor cells using primarily the PI3K/Akt pathway. Mol Cell Neurosci 2005; 30:398-407. [PMID: 16169744 DOI: 10.1016/j.mcn.2005.08.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 07/28/2005] [Accepted: 08/12/2005] [Indexed: 10/25/2022] Open
Abstract
Psychosine (galactosylsphingosine) is a toxic metabolite that accumulates in globoid cell leukodystrophy (GLD) due to the deficiency of galactocerebrosidase (GALC) activity. This results in subsequent programmed cell death of oligodendrocytes and demyelination in human patients and animal models. We investigated the potential role of insulin-like growth factor-1 (IGF-1) in modifying the apoptotic effect of psychosine in cultured mouse oligodendrocyte progenitor cells (OLP-II). We show that psychosine inhibits the phosphorylation of Akt and Erk1/Erk2 (Erk1/2), which are the main anti-apoptotic pathways of the IGF-1 receptor (IGF-1R). Although IGF-1 sustained phosphorylation of both of these pathways, it provided maximum protection to OLP-II cells from psychosine-induced cell death in a PI3K/Akt-dependent manner. The effects of IGF-1 were dose-dependent and resulted in increased IGF-1R autophosphorylation levels. Although relatively high concentrations of IGF-1 also resulted in the activation of the insulin receptor (IR), its effect was more significant on the IGF-1R.
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Affiliation(s)
- Mariam Zaka
- Department of Neurology, 1020 Locust Street, Room 394, Jefferson Medical College, Philadelphia, PA 19107, USA
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Saito A, Tominaga T, Chan PH. Neuroprotective role of neurotrophins: Relationship between nerve growth factor and apoptotic cell survival pathway after cerebral ischemia. Curr Atheroscler Rep 2005; 7:268-73. [PMID: 15975319 DOI: 10.1007/s11883-005-0018-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Neurotrophins provide a neuroprotective effect in a variety of brain diseases. Recent reports demonstrate that neurotrophins play an important role in the regulation of apoptotic neuronal cell death and in the relationship between this machinery and activation of cell survival pathways. The cascade reactions of the two major cell survival pathways, mitogen-activated protein kinase and phosphatidylinositol 3-kinase, are known to play a critical role in the regulation of apoptotic neuronal cell survival pathways. Neurotrophins such as nerve growth factor regulate these two cell survival pathways in in vitro studies. However, the role of neurotrophins in cell survival remains unclear in in vivo apoptotic neuronal cell death. We discuss the mechanism of neuroprotection by neurotrophins and also discuss cell survival effect of nerve growth factor on apoptotic neuronal cell death after in vivo cerebral ischemia.
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Affiliation(s)
- Atsushi Saito
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8533, Japan.
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32
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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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Gabryel B, Pudelko A, Malecki A. Erk1/2 and Akt kinases are involved in the protective effect of aniracetam in astrocytes subjected to simulated ischemia in vitro. Eur J Pharmacol 2005; 494:111-20. [PMID: 15212964 DOI: 10.1016/j.ejphar.2004.04.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Revised: 04/07/2004] [Accepted: 04/26/2004] [Indexed: 10/26/2022]
Abstract
The present study focused on the mechanism of cytoprotective effect of aniracetam on the primary rat astrocyte cultures exposed to simulated ischemia conditions in vitro. To study these mechanisms, the aniracetam-mediated modulation of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3-K)/Akt kinase pathways was determined. Simulated in vitro ischemia caused death of approximately 35% of astrocytes via apoptosis and decreased cell viability about 50% at 8 h. Exposure to aniracetam at concentrations of 0.1-10 microM in these conditions significantly decreased the number of apoptotic cells. Moreover, the intensification of 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyltetrazolinum bromide (MTT) conversion and the decrease of lactate dehydrogenase (LDH) release after 1 and 10 microM aniracetam treatment were observed indicating a significant increase in cell viability. When cultured astrocytes were incubated during 8 h simulated ischemia with [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene] (U0126), an extracellular regulated kinase 1 and 2 (Erk1/2) inhibitor or wortmannin, a phosphatidylinositol 3-kinase (PI3 kinase)/Akt inhibitor, the cell apoptosis was accelerated. These effects of used kinase inhibitors (both U0126 and wortmannin) were antagonized by adding 1 and 10 microM aniracetam to the culture medium. In addition, aniracetam significantly stimulated of phospho-Erk1/2 kinase and phospho-Akt expression. Maximum levels of Erk1/2 and Akt activation were observed as a result of treatment with 10 microM aniracetam. U0126 and wortmannin markedly attenuated the effects of aniracetam on expression of activated kinases. Results of the present study indicate that both Erk1/2 and PI 3-K/Akt kinase pathways are vital for cytoprotective effect of aniracetam.
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Affiliation(s)
- Bozena Gabryel
- Department of Pharmacology, Silesian Medical University, 18 Medyków Street, PL 40752 Katowice, Poland.
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34
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Cui QL, Zheng WH, Quirion R, Almazan G. Inhibition of Src-like kinases reveals Akt-dependent and -independent pathways in insulin-like growth factor I-mediated oligodendrocyte progenitor survival. J Biol Chem 2005; 280:8918-28. [PMID: 15632127 DOI: 10.1074/jbc.m414267200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin-like growth factor I (IGF-I) has been previously shown to promote survival of oligodendrocyte progenitors; however, the underlying mechanisms are not fully understood. Our aim was to investigate the involvement of phosphatidylinositol 3-kinase (PI3K), MEK1, and Src family tyrosine kinases in IGF-I-mediated oligodendrocyte progenitor survival. In agreement with previous studies, IGF-I promoted cell survival. We show that IGF-I prevented apoptosis induced by growth factor deprivation in a PI3K-dependent and MEK/ERK-independent manner. In addition, IGF-I activated Akt while inhibiting caspase-3 activation, and these effects were reversed by the PI3K inhibitors LY 294002 and wortmannin, but not by the MEK1 inhibitor PD 98059. Interestingly, PP2, a specific Src-like kinase inhibitor, blocked the tyrosine phosphorylation of Src, Fyn, and Lyn and IGF-I-stimulated Akt activation, yet had no significant effects on caspase-3 activation or progenitor survival. To further determine whether Akt is required for IGF-I-mediated survival, oligodendrocyte progenitors were transduced with defective Akt mutants or treated with an Akt inhibitor. Although the Akt mutants and inhibitor decreased Akt activity and reduced basal cell survival, IGF-I could partially rescue oligodendrocyte progenitors by decreasing caspase-3 activation. These results suggest that 1) PI3K is essential for IGF-I-promoted cell survival, 2) downstream activation of Akt-dependent and -independent pathways is involved, and 3) Src-like tyrosine kinases participate in IGF-I-induced Akt activation. Therefore, an unidentified effector(s) of PI3K appears to be involved in conferring complete IGF-I-mediated protection of oligodendrocyte progenitors.
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Affiliation(s)
- Qiao-Ling Cui
- Department of Pharmacology, McGill University, Montreal, Quebec H3G 1Y6, Canada
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35
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Defoe DM, Grindstaff RD. Epidermal growth factor stimulation of RPE cell survival: contribution of phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways. Exp Eye Res 2004; 79:51-9. [PMID: 15183100 DOI: 10.1016/j.exer.2004.02.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Indexed: 10/26/2022]
Abstract
Epidermal growth factor (EGF) previously has been shown to stimulate short-term survival in vitro of cells derived from the native amphibian retinal pigment epithelium (RPE). In the present experiments, we have examined intracellular signaling pathways responsible for mediating these survival-specific growth factor effects, distinct from proliferative effects, using the human epithelial cell line RPE D407. When maintained as single cells in suspension culture in the absence of serum and exogenous survival factors, RPE D407 cell viability gradually declined over a 3-4 day period as a result of apoptotic cell death, a pattern similar to that seen for eye-derived RPE cells. Exposure to EGF (50 ng ml(-1)) enhanced cell survival by nearly 40% and caused a parallel increase in the tyrosine phosphate content of the EGF receptor (EGFR), as determined by immunoprecipitation and Western blotting. Both effects were completely blocked by 1 microm AG1478, an EGFR-selective tyrosine kinase inhibitor. EGF also stimulated phosphorylation of the phosphatidylinositol 3'-kinase (PI3K)-dependent effector kinase Akt, as well as that of the MEK-dependent mitogen-activated kinase (MAPK), extracellular signal-regulated kinase (ERK). Furthermore, EGF-induced protection was substantially reduced by either the PI3K inhibitor LY294002 (25 microm) or the MEK inhibitor U0126 (10 microm), under conditions in which phosphorylation of Akt and ERK1/2, respectively, was blocked. Our results indicate that EGF-stimulated survival of RPE D407 cells takes place as a result of signaling through both PI3K and ERK/MAPK pathways. Further, residual anti-apoptotic activity stimulated by EGF in the presence of both blockers suggests that additional as yet unidentified growth factor-dependent survival pathways exist.
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Affiliation(s)
- Dennis M Defoe
- Department of Anatomy and Cell Biology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.
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36
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Lymn JS, Gallagher KL, Clunn GF, Fexby SE, Patel MK, Hughes AD. PDGF stimulates DNA synthesis in human vascular smooth muscle cells via a novel wortmannin-insensitive phosphatidylinositol 3-kinase. FEBS Lett 2004; 555:591-6. [PMID: 14675779 DOI: 10.1016/s0014-5793(03)01350-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The class 1(A) phosphatidylinositol 3-kinase enzymes consist of a number of heterodimeric complexes of regulatory and catalytic subunits and have been implicated in a number of cellular responses. While platelet-derived growth factor (PDGF)-induced chemotaxis of human vascular smooth muscle cells (HVSMC) is inhibited by both wortmannin and LY294002, DNA synthesis is only inhibited by LY294002. Serum-induced DNA synthesis however is inhibited by LY294002, wortmannin and rapamycin. Similarly PDGF-induced protein kinase B (PKB) activation is inhibited by LY294002 but not by wortmannin or rapamycin. In conclusion PDGF-induced DNA synthesis appears to occur through a phosphatidylinositol 3-kinase (PI3-K)-dependent, but wortmannin-insensitive, PKB/Akt pathway.
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Affiliation(s)
- Joanne S Lymn
- Clinical Pharmacology, Imperial College Faculty of Medicine, National Heart and Lung Institute, St Mary's Campus, Paddington, London W2 1NY, UK.
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37
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Althaus HH. Remyelination in multiple sclerosis: a new role for neurotrophins? PROGRESS IN BRAIN RESEARCH 2004; 146:415-32. [PMID: 14699977 DOI: 10.1016/s0079-6123(03)46026-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Multiple sclerosis (MS) is a common neurological disease, which affects young adults. Its course is unpredictable and runs over decades. It is considered as an autoimmune disease, and is neuropathologically characterized by demyelination, variable loss of oligodendroglial cells, and axonal degeneration. Demyelination provides a permitting condition for axonal degeneration, which seems to be causative of permanent neurological deficits. Hence, the current treatment, which works preferentially immunmodulatory, should be complemented by therapeutics, which improves remyelination not only for restoring conduction velocity but also for preventing an irreversible axonal damage. One strategy to achieve this aim would be to promote remyelination by stimulating oligodendroglial cells remaining in MS lesions. While central nervous system neurons were already known to respond to neurotrophins (NT), interactions with glial cells became apparent more recently. In vitro and in vivo studies have shown that NT influence proliferation, differentiation, survival, and regeneration of mature oligodendrocytes and oligodendroglial precursors in favor of a myelin repair. Two in vivo models provided direct evidence that NT can improve remyelination. In addition, their neuroprotective and anti-inflammatory role would support a repair. Hence, a wealth of data point to NT as promising therapeutical candidates.
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Affiliation(s)
- Hans H Althaus
- Max-Planck-Institute for Experimental Medicine, RU Neural Regeneration, H.-Reinstr. 3, D-37075 Göttingen, Germany.
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Cheng A, Wang S, Yang D, Xiao R, Mattson MP. Calmodulin mediates brain-derived neurotrophic factor cell survival signaling upstream of Akt kinase in embryonic neocortical neurons. J Biol Chem 2003; 278:7591-9. [PMID: 12488453 DOI: 10.1074/jbc.m207232200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
As a calcium-sensing protein, calmodulin acts as a transducer of the intracellular calcium signal for a variety of cellular responses. Although calcium is an important regulator of neuronal survival during development of the nervous system and is also implicated in the pathogenesis of neurodegenerative disorders, it is not known if calmodulin mediates these actions of calcium. To determine the role of calmodulin in regulating neuronal survival and death, we overexpressed calmodulin with mutations in all four Ca(2+)-binding sites (CaM(1-4)) or with disabled C-terminal Ca(2+)-binding sites (CaM(3,4)) in cultured neocortical neurons by adenoviral gene transfer. Long-term neuronal survival was decreased in neurons overexpressing CaM(1-4) and CaM(3,4), which could not be rescued by brain-derived neurotrophic factor (BDNF). The basal level of Akt kinase activation was decreased, and the ability of BDNF to activate Akt was completely abolished in neurons overexpressing CaM(1-4) or CaM(3,4). In contrast, BDNF-induced activation of p42/44 MAPKs was unaffected by calmodulin mutations. Treatment of neurons with calmodulin antagonists and a phosphatidylinositol 3-kinase inhibitor blocked the ability of BDNF to prevent neuronal death, whereas inhibitors of calcium/ calmodulin-dependent protein kinase II did not. Our findings demonstrate a pivotal role for calmodulin in survival signaling by BDNF in developing neocortical neurons by activating a transduction pathway involving phosphatidylinositol 3-kinase and Akt. In addition, our findings show that the C-terminal Ca(2+)-binding sites are critical for calmodulin-mediated cell survival signaling.
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Affiliation(s)
- Aiwu Cheng
- Laboratories of Neurosciences and Cardiovascular Science, Gerontology Research Center, NIA, National Institutes of Health, Baltimore, Maryland 21224, USA
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Baron W, Decker L, Colognato H, ffrench-Constant C. Regulation of integrin growth factor interactions in oligodendrocytes by lipid raft microdomains. Curr Biol 2003; 13:151-5. [PMID: 12546790 DOI: 10.1016/s0960-9822(02)01437-9] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Individual growth factors can regulate multiple aspects of behavior within a single cell during differentiation, with each signaling pathway controlled independently and also responsive to other receptors such as cell surface integrins. The mechanisms by which this is achieved remain poorly understood. Here we use myelin-forming oligodendrocytes and their precursors to examine the role of lipid rafts, cholesterol and sphingolipid-rich microdomains of the cell membrane implicated in cell signaling. In these cells, the growth factor PDGF has sequential and independent roles in proliferation and survival. We show that the oligodendrocyte PDGFalpha receptor becomes sequestered in a raft compartment at the developmental stage when PDGF ceases to promote proliferation, but is now required for survival. We also show that laminin-2, which is expressed on axons in the CNS and which provides a target-dependent signal for oligodendrocyte survival by amplification of PDGFalphaR signaling, induces clustering of the laminin binding integrin alpha6beta1 with the PDGFalphaR-containing lipid raft domains. This extracellular matrix-induced colocalization of integrin and growth factor receptor generates a signaling environment within the raft for survival-promoting PI3K/Akt activity. These results demonstrate novel signaling roles for lipid rafts that ensure the separation and amplification of growth factor signaling pathways during development.
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Affiliation(s)
- Wia Baron
- Department of Medical Genetics, Cambridge Centre for Brain Repair, University of Cambridge, CB2 1QP, Cambridge, United Kingdom
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40
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Nakazawa T, Shimura M, Tomita H, Akiyama H, Yoshioka Y, Kudou H, Tamai M. Intrinsic activation of PI3K/Akt signaling pathway and its neuroprotective effect against retinal injury. Curr Eye Res 2003; 26:55-63. [PMID: 12789537 DOI: 10.1076/ceyr.26.1.55.14254] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE The aim of this study was to determine whether the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway can function as a neuroprotective pathway following induced retinal injury. METHODS The activation of Akt was assessed by immunoblot analysis, and the role of PI3K/Akt pathway was evaluated by TUNEL staining and counting the number of retrogradely-labeled retinal ganglion cells (RGCs) in the whole retina at 168 h after injury with or without PI3K specific inhibitor, LY294002. RESULTS Akt was induced within one hr and reached a maximum 6 hrs after optic nerve clamping. The activation was observed in the RGC layer including RGCs, the inner plexiform layer, inner nuclear layer, and in the photoreceptor outer segments. The number of surviving RGCs was decreased significantly 168 hrs after injury. LY294002 partially inhibited the activation of Akt, and significantly decreased the number of surviving RGCs as compared with that of injury alone. CONCLUSIONS These results indicate that the PI3K/Akt signaling pathway is activated intrinsically and has a neuroprotective effect on injured RGCs.
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Affiliation(s)
- Toru Nakazawa
- Department of Ophthalmology, Tohoku University School of Medicine, Sendai, Japan.
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41
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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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42
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Colognato H, Baron W, Avellana-Adalid V, Relvas JB, Baron-Van Evercooren A, Georges-Labouesse E, ffrench-Constant C. CNS integrins switch growth factor signalling to promote target-dependent survival. Nat Cell Biol 2002; 4:833-41. [PMID: 12379866 DOI: 10.1038/ncb865] [Citation(s) in RCA: 208] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2002] [Revised: 08/02/2002] [Accepted: 08/09/2002] [Indexed: 01/15/2023]
Abstract
Depending on the stage of development, a growth factor can mediate cell proliferation, survival or differentiation. The interaction of cell-surface integrins with extracellular matrix ligands can regulate growth factor responses and thus may influence the effect mediated by the growth factor. Here we show, by using mice lacking the alpha(6) integrin receptor for laminins, that myelin-forming oligodendrocytes activate an integrin-regulated switch in survival signalling when they contact axonal laminins. This switch alters survival signalling mediated by neuregulin from dependence on the phosphatidylinositol-3-OH kinase (PI(3)K) pathway to dependence on the mitogen-activated kinase pathway. The consequent enhanced survival provides a mechanism for target-dependent selection during development of the central nervous system. This integrin-regulated switch reverses the capacity of neuregulin to inhibit the differentiation of precursors, thereby explaining how neuregulin subsequently promotes differentiation and survival in myelinating oligodendrocytes. Our results provide a general mechanism by which growth factors can exert apparently contradictory effects at different stages of development in individual cell lineages.
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Affiliation(s)
- Holly Colognato
- Department of Medical Genetics and Center for Brain Repair, University of Cambridge, Cambridge CB2 2PY, UK
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Clark RE, Miskimins WK, Miskimins R. Phosphatidylinositol-3 kinase p85 enhances expression from the myelin basic protein promoter in oligodendrocytes. J Neurochem 2002; 83:565-73. [PMID: 12390518 DOI: 10.1046/j.1471-4159.2002.01139.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Phosphatidylinositol-3 kinase (PI3K) is a family of enzymes that phosphorylates the D3 position of phosphoinositides in membranes which can then act as a second messenger and affect many essential cellular processes such as survival, proliferation and differentiation. Class IA PI3K is composed of two subunits: a regulatory subunit, p85, and a catalytic subunit, p110. The p85 subunit is composed of several adapter domains which, upon interaction with the appropriate molecules, transmit the signal to activate p110. We have used the spontaneously immortalized oligodendrocyte cell line, CG4, to examine the role of PI3K in maturation of the oligodendrocyte. We show that overexpression of the p85 subunit enhances expression of myelin basic protein (MBP) upon differentiation of CG4 cells and primary oligodendrocytes. In experiments in CG4 cells, neither cotransfection with the tumor suppressor PTEN, which dephosphorylates the D3 position of phosphoinositides, nor inhibition of PI3K activity with wortmannin mimics this effect. Further, we have shown that this effect is dependent on the coexpression of the two SH2 domains within p85. Thus, the p85-mediated enhancement of MBP promoter activity in oligodendrocytes appears to be independent of PI3K activity and dependent on the adapter functions of the p85 subunit's SH2 domains.
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Affiliation(s)
- Robert E Clark
- Division of Basic Biomedical Sciences, University of South Dakota School of Medicine, 414 East Clark Street, Vermillion, SD 57069, USA
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Koda M, Murakami M, Ino H, Yoshinaga K, Ikeda O, Hashimoto M, Yamazaki M, Nakayama C, Moriya H. Brain-derived neurotrophic factor suppresses delayed apoptosis of oligodendrocytes after spinal cord injury in rats. J Neurotrauma 2002; 19:777-85. [PMID: 12165137 DOI: 10.1089/08977150260139147] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We evaluated the effect of brain-derived neurotrophic factor (BDNF) on cell death after spinal cord injury. A rat spinal cord injury model was produced by static load, and continuous intrathecal BDNF or vehicle infusion was carried out either immediately or 3 days after the injury. Cell death was examined by nuclear staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). After injury, typical apoptotic cells were observed. Double staining with TUNEL and specific cell markers revealed that, soon after the injury, the apoptotic or necrotic cells at the injury site were neurons and microglia. One week after the injury, apoptotic oligodendrocytes, but not apoptotic astrocytes, were observed in the white matter rostral and caudal to the injury site, whereas few apoptotic cells were found in the gray matter. The immediate BDNF treatment significantly reduced the number of TUNEL-positive cells in the adjacent rostral site 1 and 2 weeks after the injury, and in the adjacent caudal site 3 days and 1 week after the injury, even though there was no significant difference between BDNF-treated and control rats at the injury site itself. In addition, similar antiapoptotic effects were observed in these regions 1 week after injury in rats that received BDNF treatment from the third day after injury. These findings suggest that BDNF suppresses delayed apoptosis of oligodendrocytes after spinal cord injury, for which even delayed injections are effective. BDNF administration may therefore be useful for the clinical treatment of spinal cord injury through the suppression of secondary events.
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Affiliation(s)
- Masao Koda
- Department of Orthopaedic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
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Vanhaesebroeck B, Leevers SJ, Ahmadi K, Timms J, Katso R, Driscoll PC, Woscholski R, Parker PJ, Waterfield MD. Synthesis and function of 3-phosphorylated inositol lipids. Annu Rev Biochem 2002; 70:535-602. [PMID: 11395417 DOI: 10.1146/annurev.biochem.70.1.535] [Citation(s) in RCA: 1211] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The 3-phosphorylated inositol lipids fulfill roles as second messengers by interacting with the lipid binding domains of a variety of cellular proteins. Such interactions can affect the subcellular localization and aggregation of target proteins, and through allosteric effects, their activity. Generation of 3-phosphoinositides has been documented to influence diverse cellular pathways and hence alter a spectrum of fundamental cellular activities. This review is focused on the 3-phosphoinositide lipids, the synthesis of which is acutely triggered by extracellular stimuli, the enzymes responsible for their synthesis and metabolism, and their cell biological roles. Much knowledge has recently been gained through structural insights into the lipid kinases, their interaction with inhibitors, and the way their 3-phosphoinositide products interact with protein targets. This field is now moving toward a genetic dissection of 3-phosphoinositide action in a variety of model organisms. Such approaches will reveal the true role of the 3-phosphoinositides at the organismal level in health and disease.
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Affiliation(s)
- B Vanhaesebroeck
- Ludwig Institute for Cancer Research, Riding House Street, London W1W 7BS.
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Strle K, Zhou JH, Broussard SR, Venters HD, Johnson RW, Freund GG, Dantzer R, Kelley KW. IL-10 promotes survival of microglia without activating Akt. J Neuroimmunol 2002; 122:9-19. [PMID: 11777539 DOI: 10.1016/s0165-5728(01)00444-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
IL-10 is an anti-inflammatory cytokine that has recently been shown to promote survival of neurons and glia. Here we establish that IL-10 induces phosphorylation of Stat3 on Tyr(705) and serves as a survival factor for N13 microglial cells. Recombinant IL-10 (10 ng/ml) decreases growth factor withdrawal-induced apoptosis by 50%, as assessed by TUNEL. In contrast to IL-10, IGF-I increases enzymatic activity of PI 3-kinase and causes phosphorylation on serine(473) of Akt but does not prevent microglial apoptosis. These data establish that IL-10 activates Stat3 and inhibits the mitochondrial pathway of cell death without activating the Akt cell survival pathway.
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Affiliation(s)
- Klemen Strle
- Laboratory of Immunophysiology, Department of Animal Sciences, University of Illinois, 207 ERML, 1201 W. Gregory Dr., Urbana, IL 61801, USA
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Soane L, Cho HJ, Niculescu F, Rus H, Shin ML. C5b-9 terminal complement complex protects oligodendrocytes from death by regulating Bad through phosphatidylinositol 3-kinase/Akt pathway. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:2305-11. [PMID: 11490019 DOI: 10.4049/jimmunol.167.4.2305] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Apoptosis of oligodendrocytes is induced by serum growth factor deprivation. We showed that oligodendrocytes and progenitor cells respond to serum withdrawal by a rapid decline of Bcl-2 mRNA expression and caspase-3-dependent apoptotic death. Sublytic assembly of membrane-inserted terminal complement complexes consisting of C5b, C6, C7, C8, and C9 proteins (C5b-9) inhibits caspase-3 activation and apoptotic death of oligodendrocytes. In this study, we examined an involvement of the mitochondria in oligodendrocyte apoptosis and the role of C5b-9 on this process. Decreased phosphatidylinositol 3-kinase and Akt activities occurred in association with cytochrome c release and caspase-9 activation when cells were placed in defined medium. C5b-9 inhibited the mitochondrial pathway of apoptosis in oligodendrocytes, as shown by decreased cytochrome c release and inhibition of caspase-9 activation. Phosphatidylinositol 3-phosphate kinase and Akt activities were also induced by C5b-9, and the phosphatidylinositol 3-phosphate kinase inhibitor LY294002 reversed the protective effect of C5b-9. Phosphatidylinositol 3-phosphate kinase activity was also responsible for the phosphorylation of Bad at Ser112 and Ser136. This phosphorylation resulted in dissociation of Bad from the Bad/Bcl-xL complex in a G(i)alpha-dependent manner. The mitochondrial pathway of oligodendrocyte apoptosis is, therefore, inhibited by C5b-9 through post-translational regulation of Bad. This mechanism may be involved in the promotion of oligodendrocyte survival in inflammatory demyelinating disorders affecting the CNS.
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Affiliation(s)
- L Soane
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Abstract
Lysophospholipids (LPs), including lysophosphatidic acid and sphingosine 1-phosphate, produce many cellular effects. However, the prolonged absence of any cloned and identified LP receptor has left open the question of how these lipids actually bring about these effects. The cloning and functional identification of the first LP receptor, lp(A1)/vzg-1, has led rapidly to the identification and classification of multiple orphan receptors/expression sequence tags known by many names (e.g. edg, mrec1.3, gpcr26, H218, AGR16, nrg-1) as members of a common cognate G protein-coupled receptor family. We review features of the LP receptor family, including molecular characteristics, genomics, signaling properties, and gene expression. A major question for which only partial answers are available concerns the biological significance of receptor-mediated LP signaling. Recent studies that demonstrate the role of receptor-mediated LP signaling in the nervous system, cardiovascular system, and other organ systems indicate the importance of this signaling in development, function, and pathophysiology and portend an exciting time ahead for this growing field.
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Affiliation(s)
- N Fukushima
- Neuroscience Program, Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0636, USA.
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Kim MS, Cheong YP, So HS, Lee KM, Kim TY, Oh J, Chung YT, Son Y, Kim BR, Park R. Protective effects of morphine in peroxynitrite-induced apoptosis of primary rat neonatal astrocytes: potential involvement of G protein and phosphatidylinositol 3-kinase (PI3 kinase). Biochem Pharmacol 2001; 61:779-86. [PMID: 11274962 DOI: 10.1016/s0006-2952(01)00541-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Opiates, such as morphine, have been used extensively in the clinical management of pain due to their potent analgesic effect. Astrocytes, representing a major non-neuronal cell population in the CNS, contain opioid receptors that are actively involved in several brain functions. This study was designed to evaluate the effects by which morphine, a preferential mu-opioid receptor agonist, contributes to cytotoxicity of nitric oxide (NO) species, including NO and peroxynitrite (ONOO-), in primary rat neonatal astrocytes. Primary astrocytes isolated from the cerebral cortex of 1- to 2-day-old Sprague-Dawley rats were treated with morphine, naloxone, and 3-morpholinosydnonimine (SIN-1), a donor of peroxynitrite. Morphine significantly protected primary rat astrocytes from apoptosis mediated by sodium nitroprusside, an NO donor, and SIN-1 in a dose-dependent manner, whereas it did not in other types of cells including C6 glioma, RAW 264.7, and HL-60 cells. Moreover, naloxone antagonized the protective effects of morphine on SIN-1-induced apoptosis. Morphine also inhibited the nuclear condensation and fragmentation of SIN-1-treated cells that was antagonized by naloxone pretreatment. The protective role of morphine in SIN-1-induced apoptosis was dependent on an intracellular antioxidant system such as GSH. Furthermore, the effects of morphine on SIN-1-induced cytotoxicity were prohibited by pretreatment with the G(i) protein inhibitor, pertussis toxin, and the phosphatidylinositol 3-kinase (PI3 kinase) inhibitors, wortmannin and LY294002. Taken together, these results suggest that morphine may protect primary rat astrocytes from apoptosis by NO species via the signaling cascades that involve both G protein and PI3 kinase.
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Affiliation(s)
- M S Kim
- Department of Microbiology, Wonkwang University School of Medicine, 344-2 Shinyong-dong, 570-749, Iksan Chonbuk, Korea
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Nicholas RS, Wing MG, Compston A. Nonactivated microglia promote oligodendrocyte precursor survival and maturation through the transcription factor NF-kappa B. Eur J Neurosci 2001; 13:959-67. [PMID: 11264668 DOI: 10.1046/j.0953-816x.2001.01470.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We demonstrate a role for nonactivated rat microglia in the survival and maturation of oligodendrocyte precursor cells (OPCs). Media conditioned by nonactivated microglia increase the number of surviving galactocerebroside(+) (GalC(+)) oligodendrocytes in vitro at 48 h by inhibiting the apoptosis of OPCs and stimulating their maturation to GalC+ oligodendrocytes. These effects are not observed with medium conditioned by microglia activated with interferon-gamma (IFN-gamma). Conditioned medium from nonactivated microglia is associated with upregulation in OPCs of nuclear factor of kappa binding (NF-kappa B) p65 subunit. The use of antisense to the inhibitor of kappa binding (I kappa B) induces p65 subunit activation in OPCs and, in common with medium conditioned by nonactivated microglia, also inhibits OPC apoptosis and promotes cell maturation. Anti-platelet-derived growth factor (PDGF) antibody abolishes this effect even though PDGF-A chain is expressed at similar levels within both nonactivated and IFN-gamma-activated microglia and both conditioned media have similar levels of PDGF-A chain bioactivity. However, only conditioned medium from nonactivated microglia recruit phosphatidyl-3-inositol (PI-3) kinase to the PDGF-alpha receptor and synergise with endogenous PDGF-A chain to increase NF-kappa B activation. These results suggest that, dependent on their state of activation, microglia produce soluble factors that promote oligodendrocyte development through an effect on the PDGF-alpha receptor-signalling pathway.
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Affiliation(s)
- R S Nicholas
- University of Cambridge Neurology unit, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 2QQ, UK
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