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Abstract
The neurotrophin receptor p75NTR can induce signal transduction both in vivo and in vitro. The mechanisms by which p75NTR transduces signals have remained mostly unknown. Using yeast two-hybrid system, we identified the Ran-binding protein (RanBPM) as an interactor with the intracytoplasmic domain of p75NTR (p75ICD). The interaction was then validated by immunoprecipitation in mammalian cells and immunoblotting analysis. The domain in p75ICD interacting with RanBPM was mapped to the death domain.
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Affiliation(s)
- Dong Bai
- National Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
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52
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Mukai J, Suvant P, Sato TA. Nerve growth factor-dependent regulation of NADE-induced apoptosis. VITAMINS AND HORMONES 2003; 66:385-402. [PMID: 12852261 DOI: 10.1016/s0083-6729(03)01011-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The p75 neurotrophin receptor (p75NTR) is a member of the tumor necrosis factor receptor (TNFR) superfamily, and can mediate both cell survival and cell death in response to nerve growth factor (NGF). Based on the structural and functional differences between p75NTR and the related receptors Fas or TNFR, it has been suggested that these receptors have distinct signaling functions. NADE (p75NTR-associated cell death executor) is a p75NTR-associated protein that mediates apoptosis in response to NGF by interacting with the cell death domain of p75NTR. NADE has at least four isoforms, designated as NADE2, NADE3, NADE4/Bex1, and NADE5/Bex2. NADE plays a role in NGF-induced apoptosis in oligodendrocytes and in zinc-induced neuronal death. In this review, we focus on the proapoptotic actions of NADE that regulate p75NTR signaling in response to NGF.
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Affiliation(s)
- Jun Mukai
- Division of Molecular Oncology, Department of Otolaryngology/Head & Neck Surgery and Pathology, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA
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53
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McBride CB, McPhail LT, Vanderluit JL, Tetzlaff W, Steeves JD. Caspase inhibition attenuates transection-induced oligodendrocyte apoptosis in the developing chick spinal cord. Mol Cell Neurosci 2003; 23:383-97. [PMID: 12837623 DOI: 10.1016/s1044-7431(03)00063-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
A developmental model of spinal cord injury in the embryonic chick was specifically developed to characterize the involvement of caspases in injury-induced oligodendrocyte apoptosis remote from the lesion and the ability of caspase inhibitors to attenuate this process. Developmental apoptosis in the cervical spinal cord increased within the white matter between embryonic days 13 and 18, the period of myelination of this region. Spinal cord transection during this period induced a rapid increase in apoptotic cells in the ventral and lateral white matter over several millimeters caudal to the injury. Immunostaining identified large numbers of these cells as oligodendrocytes. Catalytic activity assays and immunostaining demonstrated caspase-3-like but not caspase-1-like activity to be involved in this apoptotic response. In vivo application of specific caspase inhibitors significantly attenuated transection-induced apoptosis. Thus, we describe a developmental period during which spinal oligodendrocytes exhibited a heightened, caspase-dependent sensitivity to transection-induced apoptosis that is attenuated by caspase inhibition.
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Affiliation(s)
- Christopher B McBride
- ICORD (International Collaboration On Repair Discoveries), University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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54
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Bernardo A, Greco A, Levi G, Minghetti L. Differential lipid peroxidation, Mn superoxide, and bcl-2 expression contribute to the maturation-dependent vulnerability of oligodendrocytes to oxidative stress. J Neuropathol Exp Neurol 2003; 62:509-19. [PMID: 12769190 DOI: 10.1093/jnen/62.5.509] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To understand the basis of oligodendrocyte (OL) susceptibility to oxidative injury, purified rat OL cultures at different stages of maturation were exposed to nitric oxide (NO) donors with fast or slow kinetics of release and to tert-butyl-hydroperoxide, a membrane-permeant organic hydroperoxide. OL precursors (pre-OL) displayed the highest vulnerability to both oxygen or nitrogen reactive species, whereas mature OLs were uniquely vulnerable to long-lasting levels of NO. Cell death occurred by necrosis as well as apoptosis associated with increased caspase-3 activity and, only in the case of pre-OLs, with a decreased expression of the anti-apoptotic protein bcl-2. Pre-OLs were also more susceptible than mature OLs to lipid peroxidation, as measured by F2-isoprostane content in culture media. Finally, pre-OLs, but not mature OLs, expressed high levels of the mitochondrial scavenging enzyme Mn superoxide dismutase, suggesting that pre-OLs may efficiently convert anion superoxide into hydrogen peroxide and, paradoxically, be more predisposed than mature OLs to a toxic imbalance between hydrogen peroxide production and detoxification processes. These data suggest that susceptibility to lipid peroxidation, expression of the scavenging enzyme Mn superoxide dismutase and of the anti-apoptotic protein bcl-2, may contribute to the maturation-dependent vulnerability of OLs to oxidant injury.
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Affiliation(s)
- Antonietta Bernardo
- Neurobiology Section, Laboratory of Pathophysiology, Istituto Superiore di Sanità, Rome, Italy
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55
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Lo EH, Dalkara T, Moskowitz MA. Mechanisms, challenges and opportunities in stroke. Nat Rev Neurosci 2003; 4:399-415. [PMID: 12728267 DOI: 10.1038/nrn1106] [Citation(s) in RCA: 1276] [Impact Index Per Article: 60.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Eng H Lo
- Neuroprotection Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
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56
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Frago LM, Cañón S, de la Rosa EJ, León Y, Varela-Nieto I. Programmed cell death in the developing inner ear is balanced by nerve growth factor and insulin-like growth factor I. J Cell Sci 2003; 116:475-86. [PMID: 12508109 DOI: 10.1242/jcs.00223] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nerve growth factor induces cell death in organotypic cultures of otic vesicle explants. This cell death has a restricted pattern that reproduces the in vivo pattern of apoptosis occurring during inner ear development. In this study, we show that binding of nerve growth factor to its low affinity p75 neurotrophin receptor is essential to achieve the apoptotic response. Blockage of binding to p75 receptor neutralized nerve-growth-factor-induced cell death, as measured by immunoassays detecting the presence of cytosolic oligonucleosomes and by TUNEL assay to visualize DNA fragmentation. Nerve growth factor also induced a number of cell-death-related intracellular events including ceramide generation, caspase activation and poly-(ADP ribose) polymerase cleavage. Again, p75 receptor blockade completely abolished all of these effects. Concerning the intracellular pathway, ceramide increase depended on initiator caspases, whereas its actions depended on both initiator and effector caspases, as shown by using site-specific caspase inhibitors. Conversely, insulin-like growth factor I, which promotes cell growth and survival in the inner ear, abolished apoptosis induced by nerve growth factor. Insulin-like growth factor cytoprotective actions were accomplished, at least in part, by decreasing endogenous ceramide levels and activating Akt. Taken together, these results strongly suggest that regulation of nerve-growth-factor-induced apoptosis in the otocysts occurs via p75 receptor binding and is strictly controlled by the interaction with survival signalling pathways.
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Affiliation(s)
- Laura M Frago
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain
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57
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Alsina B, Giraldez F, Varela-Nieto I. Growth Factors and Early Development of Otic Neurons: Interactions between Intrinsic and Extrinsic Signals. Curr Top Dev Biol 2003; 57:177-206. [PMID: 14674481 DOI: 10.1016/s0070-2153(03)57006-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Berta Alsina
- DCEXS-Universitat Pomepu Fabra, Dr Aiguader 80, 08003 Barcelona, Spain
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58
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Salehi AH, Xanthoudakis S, Barker PA. NRAGE, a p75 neurotrophin receptor-interacting protein, induces caspase activation and cell death through a JNK-dependent mitochondrial pathway. J Biol Chem 2002; 277:48043-50. [PMID: 12376548 DOI: 10.1074/jbc.m205324200] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The p75 neurotrophin receptor (p75NTR) mediates signaling events leading to activation of the JNK pathway and cell death in a variety of cell types. We recently identified NRAGE, a protein that directly interacts with the p75NTR cytosolic region and facilitates p75NTR-mediated cell death. For the present study, we developed an inducible recombinant NRAGE adenovirus to dissect the mechanism of NRAGE-mediated apoptosis. Induced NRAGE expression resulted in robust activation of the JNK pathway that was not inhibited by the pharmacological mixed lineage kinase (MLK) inhibitor CEP1347. NRAGE induced cytosolic accumulation of cytochrome c, activation of Caspases-3, -9 and -7, and caspase-dependent cell death. Blocking JNK and c-Jun action by overexpression of the JNK-binding domain of JIP1 or dominant-negative c-Jun ablated NRAGE-mediated caspase activation and NRAGE-induced cell death. These findings identify NRAGE as a p75NTR interactor capable of inducing caspase activation and cell death through a JNK-dependent mitochondrial apoptotic pathway.
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Affiliation(s)
- Amir H Salehi
- Centre for Neuronal Survival, Montreal Neurological Institute, McGill University, 3801 University Avenue, Montreal, Quebec H3A 2B4, Canada
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59
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Khorchid A, Fragoso G, Shore G, Almazan G. Catecholamine-induced oligodendrocyte cell death in culture is developmentally regulated and involves free radical generation and differential activation of caspase-3. Glia 2002; 40:283-99. [PMID: 12420309 DOI: 10.1002/glia.10123] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Oligodendrocyte cultures were used to study the toxic effects of catecholamines. Our results showed that catecholamine-induced toxicity was dependent on the dose of dopamine or norepinephrine used and on the developmental stage of the cultures, with oligodendrocyte progenitors being more vulnerable. A role for oxidative stress and apoptosis on the mechanism of action of catecholamines on oligodendrocyte cell death was next assessed. Catecholamines caused a reduction in intracellular glutathione levels, an accumulation in reactive oxygen species and in heme oxygenase-1, the 32 kDa stress-induced protein. All these changes were prevented by N-acetyl-L-cysteine, a thiocompound with antioxidant activity and a precursor of glutathione, and were more pronounced in progenitors than mature cells, which could contribute to their higher susceptibility. Apoptotic cell death, as assessed by activation of caspase-9 and -3 and cleavage of poly(ADP-ribose) polymerase (a substrate of caspase-3), was only observed in oligodendrocyte progenitors. Pretreatment with zVAD, a general caspase inhibitor, prevented activation of caspase-9 and -3, DNA fragmentation, and decreased progenitors cell death. Furthermore, the expression levels of procaspase-3 and the ratio of the proapoptotic protein bax to antiapoptotic protein bcl-xl were several folds higher in immature than mature oligodendrocytes. Taken together, these results strongly suggest that the catecholamine-induced cytotoxicity in oligodendrocytes is developmentally regulated, mediated by oxidative stress, and have characteristics of apoptosis in progenitor cells.
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Affiliation(s)
- Amani Khorchid
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
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60
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Molina-Holgado E, Vela JM, Arévalo-Martín A, Almazán G, Molina-Holgado F, Borrell J, Guaza C. Cannabinoids promote oligodendrocyte progenitor survival: involvement of cannabinoid receptors and phosphatidylinositol-3 kinase/Akt signaling. J Neurosci 2002; 22:9742-53. [PMID: 12427829 PMCID: PMC6757831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
Abstract
Cannabinoids exert pleiotropic actions in the CNS, including the inhibition of inflammatory responses and the enhancement of neuronal survival after injury. Although cannabinoid receptors are distributed widely in brain, their presence has not been investigated previously in oligodendrocytes. This study examined the expression of cannabinoid type 1 (CB1) receptors in rat oligodendrocytes in vivo and in culture and explored their biological function. Expression of CB1 receptors by oligodendrocytes was demonstrated immunocytochemically in postnatal and in adult white matter as well as in oligodendrocyte cultures. Reverse transcription-PCR and Western blotting further confirmed the presence of CB1 receptors. Oligodendrocyte progenitors undergo apoptosis with the withdrawal of trophic support, as determined by TUNEL assay and caspase-3 activation, and both the selective CB1 agonist arachidonyl-2'-chloroethylamide/(all Z)-N-(2-cycloethyl)-5,8,11,14-eicosatetraenamide (ACEA) and the nonselective cannabinoid agonists HU210 and (+)-Win-55212-2 enhanced cell survival. To investigate intracellular signaling involved in cannabinoid protection, we focused on the phosphatidylinositol-3 kinase (PI3K)/Akt pathway. HU210, (+)-Win-55212-2, and ACEA elicited a time-dependent phosphorylation of Akt. Pertussis toxin abolished Akt activation, indicating the involvement of G(i)/G(o)-protein-coupled receptors. The CB1 receptor antagonist SR141716A partially inhibited Akt phosphorylation in response to HU210 and (+)-Win-55212-2 and abolished the effects of ACEA. Trophic support deprivation downregulated Akt activity, and cannabinoids recovered phospho-Akt levels. Inhibition of PI3K abrogated the survival action and the recovery of Akt activity in response to cannabinoids. SR141716A prevented only the protection conferred by ACEA. Nevertheless, SR141716A and the selective CB2 receptor antagonist SR144528 in combination inhibited the prosurvival action of HU210, which is in accordance with the finding of CB2 receptor expression by oligodendroglial cells. These data identify oligodendrocytes as potential targets of cannabinoid action in the CNS.
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Affiliation(s)
- Eduardo Molina-Holgado
- Department of Neural Plasticity, Cajal Institute, Consejo Superior de Investigaciones Cientificas, 28002 Madrid, Spain.
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61
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Troy CM, Friedman JE, Friedman WJ. Mechanisms of p75-mediated death of hippocampal neurons. Role of caspases. J Biol Chem 2002; 277:34295-302. [PMID: 12097334 DOI: 10.1074/jbc.m205167200] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neurotrophins support neuronal survival and differentiation via Trk receptors, yet can also induce cell death via the p75 receptor. In these studies, we investigated signaling mechanisms governing p75-mediated death of hippocampal neurons, specifically the role of caspases. Although p75 is structurally a member of the Fas/TNFR1 receptor family, caspase-8 was not required for p75-mediated death, unlike other members of this receptor family. In contrast, p75-mediated neuronal death was associated with mitochondrial loss of cytochrome c and required Apaf-1 and caspase-9, -6, and -3. In particular, caspase-6 plays a central role in mediating neurotrophin-induced death, illuminating a novel role for this caspase. Inhibition of DIABLO/Smac, which blocks inhibitor of apoptosis proteins, protected cells from death, whereas simultaneous inhibition of both DIABLO/Smac and MIAP3 allowed trophin-induced death to proceed. In vivo, pilocarpine-induced seizures, previously shown to up-regulate p75 expression and increase neurotrophin production, caused activation of caspase-6 and -3 and cleavage of poly(ADP-ribose) polymerase in p75-expressing hippocampal neurons. In p75(-/-) mice, no activated caspase-3 was detected, and there was a marked reduction in the number of dying neurons after pilocarpine treatment compared with wild type mice. Neurotrophin-induced p75-mediated death is likely to play an important role in mediating neuronal loss consequent to brain injury.
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Affiliation(s)
- Carol M Troy
- Department of Pathology, Taub Institute for the Study of Alzheimer's Disease and the Aging Brain, Center for Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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62
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Osterhout DJ, Marin-Husstege M, Abano P, Casaccia-Bonnefil P. Molecular mechanisms of enhanced susceptibility to apoptosis in differentiating oligodendrocytes. J Neurosci Res 2002; 69:24-9. [PMID: 12111812 DOI: 10.1002/jnr.10230] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Several studies have shown that the progression of oligodendrocyte progenitors along the lineage correlates with increased susceptibility to death stimuli. The molecular basis of this phenomenon remains unclear. This study demonstrates that the protein levels of several proapoptotic molecules, including Bax, Bad (nonphosphorylated form), and certain caspase proforms, increase during oligodendrocyte development. In contrast, the steady-state levels of antiapoptotic molecules, such as Bcl2 and Bcl(XL), remain constant. This altered equilibrium between proapoptotic and antiapoptotic molecules correlates with increased cytochrome C in the cytosol. We conclude that, as oligodendrocytes mature, their susceptibility to apoptosis increases because of a change in the balance between protective mechanisms and proapoptotic pathways. This suggests the possible existence of a death susceptibility program, which is intrinsic to differentiating oligodendrocyte progenitors.
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Affiliation(s)
- D J Osterhout
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, USA
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63
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Liu HN, Giasson BI, Mushynski WE, Almazan G. AMPA receptor-mediated toxicity in oligodendrocyte progenitors involves free radical generation and activation of JNK, calpain and caspase 3. J Neurochem 2002; 82:398-409. [PMID: 12124441 DOI: 10.1046/j.1471-4159.2002.00981.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The molecular mechanisms underlying AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate) receptor-mediated excitotoxicity were characterized in rat oligodendrocyte progenitor cultures. Activation of AMPA receptors, in the presence of cyclothiazide to selectively block desensitization, produced a massive Ca(2+) influx and cytotoxicity which were blocked by the antagonists CNQX and GYKI 52466. A role for free radical generation in oligodendrocyte progenitor cell death was deduced from three observations: (i) treatment with AMPA agonists decreased intracellular glutathione; (ii) depletion of intracellular glutathione with buthionine sulfoximine potentiated cell death; and (iii) the antioxidant N -acetylcysteine replenished intracellular glutathione and protected cultures from AMPA receptor-mediated toxicity. Cell death displayed some characteristics of apoptosis, including DNA fragmentation, chromatin condensation and activation of caspase-3 and c-Jun N-terminal kinase (JNK). A substrate of calpain and caspase-3, alpha-spectrin, was cleaved into characteristic products following treatment with AMPA agonists. In contrast, inhibition of either caspase-3 by DEVD-CHO or calpain by PD 150606 protected cells from excitotoxicity. Our results indicate that overactivation of AMPA receptors causes apoptosis in oligodendrocyte progenitors through mechanisms involving Ca(2+) influx, depletion of glutathione, and activation of JNK, calpain, and caspase-3.
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Affiliation(s)
- Hsueh-Ning Liu
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
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64
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Yu SY, Yoo SJ, Yang L, Zapata C, Srinivasan A, Hay BA, Baker NE. A pathway of signals regulating effector and initiator caspases in the developing Drosophila eye. Development 2002; 129:3269-78. [PMID: 12070100 DOI: 10.1242/dev.129.13.3269] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Regulated cell death and survival play important roles in neural development. Extracellular signals are presumed to regulate seven apparent caspases to determine the final structure of the nervous system. In the eye, the EGF receptor, Notch, and intact primary pigment and cone cells have been implicated in survival or death signals. An antibody raised against a peptide from human caspase 3 was used to investigate how extracellular signals controlled spatial patterning of cell death. The antibody crossreacted specifically with dying Drosophila cells and labelled the activated effector caspase Drice. It was found that the initiator caspase Dronc and the proapoptotic gene head involution defective were important for activation in vivo. Dronc may play roles in dying cells in addition to activating downstream effector caspases. Epistasis experiments ordered EGF receptor, Notch, and primary pigment and cone cells into a single pathway that affected caspase activity in pupal retina through hid and Inhibitor of Apoptosis Proteins. None of these extracellular signals appeared to act by initiating caspase activation independently of hid. Taken together, these findings indicate that in eye development spatial regulation of cell death and survival is integrated through a single intracellular pathway.
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Affiliation(s)
- Sun-Yun Yu
- Department of Molecular Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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65
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Ming X, Li W, Maeda Y, Blumberg B, Raval S, Cook SD, Dowling PC. Caspase-1 expression in multiple sclerosis plaques and cultured glial cells. J Neurol Sci 2002; 197:9-18. [PMID: 11997061 DOI: 10.1016/s0022-510x(02)00030-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Caspase-1 is responsible for processing inflammatory cytokines and is associated with the induction of apoptosis. Using RT-PCR, we found that caspase-1 mRNA transcripts from frozen brain extracts were significantly elevated in multiple sclerosis (MS) compared to controls. Immunohistochemical staining using a specific antiserum confirmed the marked up regulation of caspase-1 within acute and chronic MS plaques, while little staining was seen in control brains. In addition to the expected caspase-1 expression in microglia and infiltrating perivascular mononuclear cells, we found that cytoplasmic caspase-1 expression was sharply increased in the resident oligodendrocytes of MS lesions. The TUNEL reaction for fragmented DNA co-localized over an occasional caspase-1-expressing cell and large numbers of caspase-1-positive "corpses" were observed within phagocytic macrophages of an acute evolving MS lesion. Studies using an immortalized human oligodendroglial hybrid cell line exposed to cytokine challenge showed that death induction was blocked by the caspase-1-like inhibitor Z-YVAD-fmk, while the caspase-3-like inhibitor Z-DEVD-fmk was less effective. Cellular levels of procaspase-1 were reduced compared to controls in oligodendroglia induced to die by cytokine challenge, as judged by Western immunoblotting. Our results suggest that caspase-1 may play a role in the inflammatory and apoptotic processes associated with MS pathogenesis.
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Affiliation(s)
- Xue Ming
- Department of Neurosciences, UMDNJ-New Jersey Medical School, Newark, NJ, USA
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66
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Mukai J, Shoji S, Kimura MT, Okubo S, Sano H, Suvanto P, Li Y, Irie S, Sato TA. Structure-function analysis of NADE: identification of regions that mediate nerve growth factor-induced apoptosis. J Biol Chem 2002; 277:13973-82. [PMID: 11830582 DOI: 10.1074/jbc.m106342200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nerve growth factor (NGF) can induce apoptosis in neural cells via activation of the low affinity neurotrophin receptor p75NTR. NADE (p75NTR-associated cell death executor) is a p75NTR-associated protein that mediates apoptosis in response to NGF by interacting with the death domain of p75NTR in 293T, PC12, and nnr5 cells (Mukai, J., Hachiya, T., Shoji-Hoshino, S., Kimura, M. T., Nadano, D., Suvanto, P., Hanaoka, T., Li, Y., Irie, S., Greene, L. A., and Sato, T. A. (2000) J. Biol. Chem. 275, 17566-17570). We performed extensive mutational analysis on NADE, to better characterize its structural and functional features. Truncation of a minimal region, including amino acid residues 41-71 of NADE, was found to be sufficient to induce apoptosis. The designated regulatory region includes the C-terminal amino acid residues (72-112) and is essential for NGF-dependent regulation of NADE-induced apoptosis. Furthermore, the mutants with amino acid substitutions in the leucine-rich nuclear export signal (NES) sequence (residues 90-100) abolished the export of NADE from the nucleus to the cytoplasm. Mutation of the NES also abolished self-association of NADE, its interaction with p75NTR, and NGF-dependent apoptosis. Expression of a fragment of NADE (amino acid residues 81-124) blocked NGF-induced apoptosis in oligodendrocytes, suggesting that this region has a dominant negative effect on NGF/p75NTR-induced apoptosis. These studies identify distinct regions of NADE that are involved in regulating specific functions involved in p75NTR signal transduction.
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Affiliation(s)
- Jun Mukai
- Division of Molecular Oncology, Department of Otolaryngology/Head & Neck Surgery and Pathology, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA
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67
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Perini G, Della-Bianca V, Politi V, Della Valle G, Dal-Pra I, Rossi F, Armato U. Role of p75 neurotrophin receptor in the neurotoxicity by beta-amyloid peptides and synergistic effect of inflammatory cytokines. J Exp Med 2002; 195:907-18. [PMID: 11927634 PMCID: PMC2193732 DOI: 10.1084/jem.20011797] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The neurodegenerative changes in Alzheimer's disease (AD) are elicited by the accumulation of beta-amyloid peptides (Abeta), which damage neurons either directly by interacting with components of the cell surface to trigger cell death signaling or indirectly by activating astrocytes and microglia to produce inflammatory mediators. It has been recently proposed that the p75 neurotrophin receptor (p75(NTR)) is responsible for neuronal damage by interacting with Abeta. By using neuroblastoma cell clones lacking the expression of all neurotrophin receptors or engineered to express full-length or various truncated forms of p75(NTR), we could show that p75(NTR) is involved in the direct signaling of cell death by Abeta via the function of its death domain. This signaling leads to the activation of caspases-8 and -3, the production of reactive oxygen intermediates and the induction of an oxidative stress. We also found that the direct and indirect (inflammatory) mechanisms of neuronal damage by Abeta could act synergistically. In fact, TNF-alpha and IL-1beta, cytokines produced by Abeta-activated microglia, could potentiate the neurotoxic action of Abeta mediated by p75(NTR) signaling. Together, our results indicate that neurons expressing p75(NTR), mostly if expressing also proinflammatory cytokine receptors, might be preferential targets of the cytotoxic action of Abeta in AD.
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Affiliation(s)
- Giovanni Perini
- Department of Biology, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
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68
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Back SA, Han BH, Luo NL, Chricton CA, Xanthoudakis S, Tam J, Arvin KL, Holtzman DM. Selective vulnerability of late oligodendrocyte progenitors to hypoxia-ischemia. J Neurosci 2002; 22:455-63. [PMID: 11784790 PMCID: PMC6758669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
In the premature infant, hypoxic-ischemic damage to the cerebral white matter [periventricular leukomalacia (PVL)] is a common and leading cause of brain injury that often results in chronic neurologic disability from cerebral palsy. The cellular basis for the propensity of white matter injury to occur in the developing brain and the greater resistance of the adult white matter to similar injury remains unknown. By using a neonatal rat model of hypoxic-ischemic injury, we found that the mechanism of perinatal white matter injury involved maturation-dependent vulnerability in the oligodendroctye (OL) lineage. The timing of appearance of late OL progenitors was the major developmental factor that accounted for the susceptibility of the neonatal white matter to injury. Late OL progenitors were the major OL lineage stage killed by apoptosis, whereas early OL progenitors and more mature OLs were highly resistant. The density of pyknotic late OL progenitors was significantly increased in the ischemic hemisphere (67 +/- 31 cells/mm2) versus the control hemisphere (2.2 +/- 0.4 cells/mm2; mean +/- SEM; p = 0.05), which resulted in the death of 72 +/- 6% of this OL stage. Surviving late OL progenitors displayed a reactive response in which an increase in cell density was accompanied by accelerated maturation to a P27/kip1-positive oligodendrocyte. Because we showed recently that late OL progenitors populate human cerebral white matter during the high risk period for PVL (Back et al., 2001), maturation-dependent vulnerability of OL progenitors to hypoxia-ischemia may underlie the selective vulnerability to PVL of the white matter in the premature infant.
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Affiliation(s)
- Stephen A Back
- Department of Pediatrics, Oregon Health Sciences University, Portland, Oregon 97201, USA.
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69
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Valdo P, Stegagno C, Mazzucco S, Zuliani E, Zanusso G, Moretto G, Raine CS, Bonetti B. Enhanced expression of NGF receptors in multiple sclerosis lesions. J Neuropathol Exp Neurol 2002; 61:91-8. [PMID: 11829348 DOI: 10.1093/jnen/61.1.91] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The receptor for nerve growth factor (NGF) comprises a 75-kDa (NGFRp75) and a tyrosine kinase A (TrkA) subunit. In view of conflicting opinions on the identity of glial targets of NGF in human central nervous system (CNS), we examined the cellular distribution of both NGF receptor subunits in normal CNS and in chronic multiple sclerosis (MS) lesions. For this, we compared the pattern of recognition of 2 monoclonal antibodies (mAbs) and a polyclonal antiserum to NGFRp75. Only the 2 mAbs specifically recognized NGFRp75, while the polyclonal antiserum showed widespread reactivity. In normal CNS and silent MS lesions, immunohistochemistry with anti-NGFRp75 mAbs and for TrkA revealed perivascular cell reactivity. At the edge of chronic active MS lesions, selective NGFRp75 staining was prominent on reactive astrocytes, while throughout the lesion, NGFRp75 was expressed on microglia/macrophages. The vast majority of mature or precursor oligodendrocytes did not express NGFRp75. Both NGF receptors were co-expressed on a subset of inflammatory cells. Immunoreactivity for NGFRp75 on glial and immune cells did not correlate with the distribution of apoptotic figures, as detected by TUNEL. Thus, expression of NGF receptors in active MS lesions suggests a role for NGF in regulating the autoimmune response at both immune and glial cell levels.
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Affiliation(s)
- Paola Valdo
- Clinica Neurologica, Ospedale Policlinico, Azienda Ospedaliera of Verona, Italy
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70
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Harrington AW, Kim JY, Yoon SO. Activation of Rac GTPase by p75 is necessary for c-jun N-terminal kinase-mediated apoptosis. J Neurosci 2002; 22:156-66. [PMID: 11756498 PMCID: PMC6757583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
The neurotrophin receptor p75 can induce apoptosis both in vitro and in vivo. The mechanisms by which p75 induces apoptosis have remained mostly unknown. Here, we report that p75 activates Rac GTPase, which in turn activates c-jun N-terminal kinase (JNK), including an injury-specific JNK3, in an NGF-dependent manner. N17Rac blocks this JNK activation and subsequent NGF-dependent apoptosis, indicating that activation of Rac GTPase is required for JNK activation and apoptosis induced by p75. In addition, p75-mediated Rac activation is modulated by coactivation of Trk, identifying Rac GTPase as one of the key molecules whose activity is critical for cell survival and death in neurotrophin signaling. The crucial role of the JNK pathway in p75 signaling is further confirmed by the results that blocking p75 from signaling via the JNK pathway or suppressing the JNK activity itself led to inhibition of NGF-dependent death. Together, these results indicate that the apoptotic machinery of p75 comprises Rac GTPase and JNK.
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Affiliation(s)
- Anthony W Harrington
- Neurobiotech Center and Department of Neuroscience, Ohio State University, Columbus, Ohio 43210, USA
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71
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Abstract
Nerve growth factor (NGF) was discovered 50 years ago as a molecule that promoted the survival and differentiation of sensory and sympathetic neurons. Its roles in neural development have been characterized extensively, but recent findings point to an unexpected diversity of NGF actions and indicate that developmental effects are only one aspect of the biology of NGF. This article considers expanded roles for NGF that are associated with the dynamically regulated production of NGF and its receptors that begins in development, extends throughout adult life and aging, and involves a surprising variety of neurons, glia, and nonneural cells. Particular attention is given to a growing body of evidence that suggests that among other roles, endogenous NGF signaling subserves neuroprotective and repair functions. The analysis points to many interesting unanswered questions and to the potential for continuing research on NGF to substantially enhance our understanding of the mechanisms and treatment of neurological disorders.
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Affiliation(s)
- M V Sofroniew
- Department of Neurobiology and Brain Research Institute, University of California Los Angeles, Los Angeles, California 90095-1763, USA.
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72
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Wang X, Bauer JH, Li Y, Shao Z, Zetoune FS, Cattaneo E, Vincenz C. Characterization of a p75(NTR) apoptotic signaling pathway using a novel cellular model. J Biol Chem 2001; 276:33812-20. [PMID: 11451944 DOI: 10.1074/jbc.m010548200] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The p75 neurotrophin receptor (p75(NTR)) belongs to the tumor necrosis factor receptor/nerve growth factor receptor superfamily. In some cells derived from neuronal tissues it causes cell death through a poorly characterized pathway. We developed a neuronal system using conditionally immortalized striatal neurons, in which the expression of p75(NTR) is inducibly controlled by the ecdysone receptor. In these cells p75(NTR) induces apoptosis through its death domain in a nerve growth factor-independent manner. Caspases 9, 6, and 3 are activated by receptor expression indicating the activation of the common effector pathway of apoptosis. Cell death is blocked by a dominant negative form of caspase 9 and Bcl-X(L) consistent with a pathway that involves mitochondria. Significantly, the viral flice inhibitory protein E8 protects from p75(NTR)-induced cell death indicating that death effector domains are involved. A p75(NTR) construct with a deleted death domain dominantly interferes with p75(NTR) signaling, implying that receptor multimerization is required. However, in contrast to the other receptors of the family, p75(NTR)-mediated apoptosis does not involve the adaptor proteins Fas-associated death domain protein or tumor necrosis factor-associated death domain protein, and the apical caspase 8 is not activated. We conclude that p75(NTR) signals apoptosis by similar mechanisms as other death receptors but uses different adaptors and apical caspases.
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Affiliation(s)
- X Wang
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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73
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Khursigara G, Bertin J, Yano H, Moffett H, DiStefano PS, Chao MV. A prosurvival function for the p75 receptor death domain mediated via the caspase recruitment domain receptor-interacting protein 2. J Neurosci 2001; 21:5854-63. [PMID: 11487608 PMCID: PMC6763175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2000] [Revised: 05/08/2001] [Accepted: 05/18/2001] [Indexed: 02/21/2023] Open
Abstract
In addition to promoting cell survival, neurotrophins also can elicit apoptosis in restricted cell types. Recent results indicate that nerve growth factor (NGF) can induce Schwann cell death via engagement of the p75 neurotrophin receptor. Here we describe a novel interaction between the p75 receptor and receptor-interacting protein 2, RIP2 (RICK/CARDIAK), that accounts for the ability of neurotrophins to choose between a survival-versus-death pathway. RIP2, an adaptor protein with a serine threonine kinase and a caspase recruitment domain (CARD), is highly expressed in dissociated Schwann cells and displays an endogenous association with p75. RIP2 binds to the death domain of p75 via its CARD domain in an NGF-dependent manner. The introduction of RIP2 into Schwann cells deficient in RIP2 conferred NGF-dependent nuclear transcription factor-kappaB (NF-kappaB) activity and decreased the cell death induced by NGF. Conversely, the expression of a dominant-negative version of RIP2 protein resulted in a loss of NGF-induced NF-kappaB induction and increased NGF-mediated cell death. These results indicate that adaptor proteins like RIP2 can provide a bifunctional switch for cell survival or cell death decisions mediated by the p75 neurotrophin receptor.
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Affiliation(s)
- G Khursigara
- Weill Medical College of Cornell University, New York, New York 10021, USA
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74
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Beer R, Franz G, Krajewski S, Pike BR, Hayes RL, Reed JC, Wang KK, Klimmer C, Schmutzhard E, Poewe W, Kampfl A. Temporal and spatial profile of caspase 8 expression and proteolysis after experimental traumatic brain injury. J Neurochem 2001; 78:862-73. [PMID: 11520907 DOI: 10.1046/j.1471-4159.2001.00460.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent studies have demonstrated that the downstream caspases, such as caspase 3, act as executors of the apoptotic cascade after traumatic brain injury (TBI) in vivo. However, little is known about the involvement of caspases in the initiation phase of apoptosis, and the interaction between these initiator caspases (e.g. caspase 8) and executor caspases after experimental brain injuries in vitro and in vivo. This study investigated the temporal expression and cell subtype distribution of procaspase 8 and cleaved caspase 8 p20 from 1 h to 14 days after cortical impact-induced TBI in rats. Caspase 8 messenger RNA levels, estimated by semiquantitaive RT-PCR, were elevated from 1 h to 72 h in the traumatized cortex. Western blotting revealed increased immunoreactivity for procaspase 8 and the proteolytically active subunit of caspase 8, p20, in the ipsilateral cortex from 6 to 72 h after injury, with a peak at 24 h after TBI. Similar to our previous studies, immunoreactivity for the p18 fragment of activated caspase 3 also increased in the current study from 6 to 72 h after TBI, but peaked at a later timepoint (48 h) as compared with proteolyzed caspase 8 p20. Immunohistologic examinations revealed increased expression of caspase 8 in neurons, astrocytes and oligodendrocytes. Assessment of DNA damage using TUNEL identified caspase 8- and caspase 3-immunopositive cells with apoptotic-like morphology in the cortex ipsilateral to the injury site, and immunohistochemical investigations of caspase 8 and activated caspase 3 revealed expression of both proteases in cortical layers 2-5 after TBI. Quantitative analysis revealed that the number of caspase 8 positive cells exceeds the number of caspase 3 expressing cells up to 24 h after impact injury. In contrast, no evidence of caspase 8 and caspase 3 activation was seen in the ipsilateral hippocampus, contralateral cortex and hippocampus up to 14 days after the impact. Our results provide the first evidence of caspase 8 activation after experimental TBI and suggest that this may occur in neurons, astrocytes and oligodendrocytes. Our findings also suggest a contributory role of caspase 8 activation to caspase 3 mediated apoptotic cell death after experimental TBI in vivo.
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Affiliation(s)
- R Beer
- Department of Neurology, University Hospital Innsbruck, Austria
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75
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Roux PP, Bhakar AL, Kennedy TE, Barker PA. The p75 neurotrophin receptor activates Akt (protein kinase B) through a phosphatidylinositol 3-kinase-dependent pathway. J Biol Chem 2001; 276:23097-104. [PMID: 11312266 DOI: 10.1074/jbc.m011520200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Akt kinase plays a crucial role in supporting Trk-dependent cell survival, whereas the p75 neurotrophin receptor (p75NTR) facilitates cellular apoptosis. The precise mechanism that p75NTR uses to promote cell death is not certain, but one possibility is that p75NTR-dependent ceramide accumulation inhibits phosphatidylinositol 3-kinase-mediated Akt activation. To test this hypothesis, we developed a system for examining p75NTR-dependent apoptosis and determined the effect of p75NTR on Akt activation. Surprisingly, p75NTR increased, rather than decreased, Akt phosphorylation in a variety of cell types, including human Niemann-Pick fibroblasts, which lack acidic sphingomyelinase activity. The p75NTR expression level required to elicit Akt phosphorylation was much lower than that required to activate the JNK pathway or to mediate apoptosis. We show that p75NTR-dependent Akt phosphorylation was independent of TrkA signaling, required active phosphatidylinositol 3-kinase, and was associated with increased tyrosine phosphorylation of p85 and Shc and with reduced cytosolic tyrosine phosphatase activity. Finally, we show that p75NTR expression increased survival in cells exposed to staurosporine or subjected to serum withdrawal. These findings indicate that p75NTR facilitates cell survival through novel signaling cascades that result in Akt activation.
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Affiliation(s)
- P P Roux
- Centre for Neuronal Survival, Montreal Neurological Institute, and the Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
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76
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Ramachandran V, Perez A, Chen J, Senthil D, Schenker S, Henderson GI. In Utero Ethanol Exposure Causes Mitochondrial Dysfunction, Which Can Result in Apoptotic Cell Death in Fetal Brain: A Potential Role for 4-Hydroxynonenal. Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02292.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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77
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Abstract
Neurotrophins rely on Trk tyrosine kinase and p75 receptors for signal transduction. Recently, other roles for these receptors have been identified. Many questions have been raised about the mechanism by which these receptors mediate diverse cellular functions. Studies indicate a great deal of neurotrophin signaling specificity may stem from ligand-receptor selectivity and intracellular protein recruitment.
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MESH Headings
- Animals
- Antigens, CD/drug effects
- Antigens, CD/physiology
- Antigens, Neoplasm
- Apoptosis/drug effects
- Apoptosis/physiology
- Cell Count
- DNA-Binding Proteins/physiology
- Humans
- Ligands
- Macromolecular Substances
- Membrane Proteins/physiology
- Neoplasm Proteins
- Nerve Growth Factors/physiology
- Nerve Tissue Proteins/physiology
- Neurons/metabolism
- Phosphoproteins
- Receptors, Nerve Growth Factor/classification
- Receptors, Nerve Growth Factor/drug effects
- Receptors, Nerve Growth Factor/physiology
- Receptors, Tumor Necrosis Factor/drug effects
- Receptors, Tumor Necrosis Factor/physiology
- Receptors, Tumor Necrosis Factor, Type II
- Schwann Cells/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Tumor Necrosis Factor-alpha/physiology
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Affiliation(s)
- F S Lee
- Weill Medical College of Cornell University Medical College, New York, New York 10021, USA
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78
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Casha S, Yu WR, Fehlings MG. Oligodendroglial apoptosis occurs along degenerating axons and is associated with FAS and p75 expression following spinal cord injury in the rat. Neuroscience 2001; 103:203-18. [PMID: 11311801 DOI: 10.1016/s0306-4522(00)00538-8] [Citation(s) in RCA: 293] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Apoptosis or programmed cell death has been reported after CNS trauma. However, the significance of this mechanism in the pathophysiology of spinal cord injury, in particular at the cervical level, requires further investigation. In the present study, we used the extradural clip compression model in the rat to examine the cellular distribution of apoptosis following cervical spinal cord injury, the relationship between glial apoptosis and post-traumatic axonal degeneration and the possible role of apo[apoptosis]-1, CD95 (FAS) and p75 in initiating post-traumatic glial apoptosis. In situ terminal-deoxy-transferase mediated dUTP nick end labeling revealed apoptotic cells, largely oligodendrocytes as identified by cell specific markers, in grey and white matter following spinal cord injury. Apoptotic cell death was confirmed using electron microscopy and by the demonstration of DNA laddering on agarose gel electrophoresis. Beta-amyloid precursor protein was used as a molecular marker of axonal degeneration on western blots and immunohistochemistry. Degeneration of axons was temporally and spatially co-localized with glial apoptosis. FAS and p75 protein expression was seen in astrocytes, oligodendrocytes and microglia, and was also seen in some apoptotic glia after cord injury. Both FAS and p75 increased in expression in a temporal course, which mirrored the development of cellular apoptosis. The downstream caspases 3 and 8, which are linked to FAS and p75, demonstrated activation at times of maximal apoptosis, while FLIP-L an inhibitor of caspase 8, decreased at times of maximal apoptosis. We conclude that axonal degeneration after traumatic spinal cord injury is associated with glial, in particular oligodendroglial, apoptosis. Activation of the FAS and p75 death receptor pathways may be involved in initiating this process.
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Affiliation(s)
- S Casha
- Division of Neurosurgery, Toronto Western Research, The University Health Network, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
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79
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Beesley JS, Lavy L, Eraydin NB, Siman R, Grinspan JB. Caspase-3 activation in oligodendrocytes from the myelin-deficient rat. J Neurosci Res 2001; 64:371-9. [PMID: 11340644 DOI: 10.1002/jnr.1088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The myelin-deficient (MD) rat has a point mutation in its proteolipid protein (PLP) gene that causes severe dysmyelination and oligodendrocyte cell death. Using an in vitro model, we have shown that MD oligodendrocytes initially differentiate similarly to wild-type cells, expressing galactocerebroside, 2',3'-cyclic nucleotide 3'-phosphodiesterase, and myelin basic protein. However, at the time when PLP expression would normally begin, the MD oligodendrocytes die via an apoptotic pathway involving caspase activation. The active form of caspase-3 was detected, along with the cleavage products of poly-(ADP-ribose) polymerase (PARP) and spectrin, major targets of caspase-mediated proteolysis. A specific inhibitor of casapse-3, Ac-DEVD-CMK, reduced apoptosis in MD oligodendrocytes, but the rescued cells did not mature fully or express myelin-oligodendrocyte glycoprotein. These results suggest that mutant PLP affects not only cell death but also oligodendrocyte differentiation.
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Affiliation(s)
- J S Beesley
- Department of Neurology Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
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80
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Katz GG, Shear NH, Malkiewicz IM, Valentino K, Neuman MG. Signaling for ethanol-induced apoptosis and repair in vitro. Clin Biochem 2001; 34:219-27. [PMID: 11408020 DOI: 10.1016/s0009-9120(01)00218-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES To evaluate whether caspases are involved in ethanol (EtOH)-induced apoptosis and if polyenylphosphatidylcholine (PPC) affects apoptosis, in vitro in Hep G2 cells. METHODS Cells were treated with 100 mmol/L EtOH for 24 h and with 2 doses of 100 mmol/L EtOH (1/24 h) in the presence of absence of 20 mmol/L of PPC or 50 micromol/L caspase 3 inhibitor (IDN). Cells were analyzed for apoptosis by transmission electron microscopy (TEM) 6000 cells/treatment, DNA fragmentation by ELISA and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (T dt-mediated d-UTP) nick-end-labeling, TUNEL. RESULTS 100 mmol/L dose of EtOH resulted in 22 +/- 2.5% (p < 0.001) apoptosis (vs. control). Two consecutive doses of 100 mmol/L EtOH for 24 h each caused 36 +/- 3.0% (p < 0.001 vs. control and p < 0.05 vs. one dose). PPC significantly reduced apoptosis (vs. non exposed to PPC): 100 mmol/L -12 +/- 1.5% (p < 0.05) and 2 x 10(-)(0) mmol/L -20 +/- 2.0% (p < 0.001). Pretreatment with 50 micromol caspase inhibitor reduced EtOH-induced apoptosis in a similar proportion. CONCLUSIONS PPC downregulates EtOH-apoptosis by a mechanism similar to caspase inhibition.
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Affiliation(s)
- G G Katz
- Division of Clinical Pharmacology, Sunnybrook & Women's College Health Sciences Centre, Toronto, Canada
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81
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Allington C, Shamovsky IL, Ross GM, Riopelle RJ. Zinc inhibits p75NTR-mediated apoptosis in chick neural retina. Cell Death Differ 2001; 8:451-6. [PMID: 11423905 DOI: 10.1038/sj.cdd.4400831] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2000] [Revised: 11/24/2000] [Accepted: 12/04/2000] [Indexed: 11/09/2022] Open
Abstract
It has previously been documented that Zn2+ inhibits TrkA-mediated effects of NGF. To evaluate the ability of Zn2+ to attenuate the biological activities of NGF mediated by p75NTR, we characterized the effects of this transition metal cation on both binding and the pro-apoptotic properties of the NGF-p75NTR interaction. Binding of NGF to p75NTR displayed higher affinity in embryonic chick retinal cells than in PC12 cells. NGF induced apoptosis in dissociated cultures of chick neural retina. The addition of 100 microM Zn2+ inhibited binding and chemical cross-linking of 125I-NGF to p75NTR, and also attenuated apoptosis mediated by this ligand-receptor interaction. These studies lead to the conclusion that Zn2+ antagonizes NGF/p75NTR-mediated signaling, suggesting that the effect of this transition metal cation can be either pro- or anti-apoptotic depending on the cellular context.
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Affiliation(s)
- C Allington
- Department of Physiology, Queen's University, Kingston Ontario, Canada K7L 3N6
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82
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Masumura M, Hata R, Nagai Y, Sawada T. Oligodendroglial cell death with DNA fragmentation in the white matter under chronic cerebral hypoperfusion: comparison between normotensive and spontaneously hypertensive rats. Neurosci Res 2001; 39:401-12. [PMID: 11274739 DOI: 10.1016/s0168-0102(01)00195-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the neuropathological and biochemical changes in the white matter of normotensive Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) after bilateral carotid artery ligation (BCAL). One week after BCAL, both WKY and SHR showed white matter rarefaction and vacuolation with reduced oligodendrocytes, but there was no difference between WKY and SHR. On the other hand, vacuoles formed by oligodendroglial cell death were increased significantly from 2 to 4 weeks in the optic tract and fimbria fornix of hypoperfused SHR. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP in situ nick end labeling (TUNEL)-positive cells and lectin-positive microglia increased in number and intensities of staining more markedly in SHR than in WKY. In situ cell death detection ELISA supported these results quantitatively. RT-PCR represented the expression of TNF-alpha, TNF receptor 1 (p55), caspase-2 (Ich-1) and -3 (CPP32) mRNAs in both WKY and SHR brains after BCAL. Immunohistochemical analyses revealed that TNF-alpha, TNF receptor 1 (p55), Ich-1 and CPP32 immunoreactive cells could also be detected in the white matter regions of hypoperfused SHR. These results suggested that local production of TNF-alpha by the activated microglia might selectively induce oligodendroglial cell death through the death domain-containing TNF receptor 1 (p55), caspase-2 or -3 activation, resulting in white matter changes as a primary pathological feature.
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MESH Headings
- Animals
- Apoptosis/physiology
- Blood Pressure/physiology
- Cerebrovascular Circulation/physiology
- Chronic Disease
- DNA Fragmentation/physiology
- Dementia, Vascular/etiology
- Dementia, Vascular/metabolism
- Dementia, Vascular/physiopathology
- Hypertension/complications
- Hypertension/physiopathology
- Hypoxia-Ischemia, Brain/metabolism
- Hypoxia-Ischemia, Brain/pathology
- Hypoxia-Ischemia, Brain/physiopathology
- Immunohistochemistry
- Male
- Nerve Fibers, Myelinated/metabolism
- Nerve Fibers, Myelinated/pathology
- Oligodendroglia/metabolism
- Oligodendroglia/pathology
- Prosencephalon/metabolism
- Prosencephalon/pathology
- Prosencephalon/physiopathology
- RNA, Messenger/metabolism
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
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Affiliation(s)
- M Masumura
- BF Research Institute, c/o National Cardiovascular Center, 7-1, 5-Chome, Fujishiro-dai, Suita, Osaka 565-0873, Japan.
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83
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Edsall LC, Cuvillier O, Twitty S, Spiegel S, Milstien S. Sphingosine kinase expression regulates apoptosis and caspase activation in PC12 cells. J Neurochem 2001; 76:1573-84. [PMID: 11238741 DOI: 10.1046/j.1471-4159.2001.00164.x] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Sphingosine-1-phosphate (SPP), a bioactive sphingolipid metabolite, suppresses apoptosis of many types of cells, including rat pheochromocytoma PC12 cells. Elucidating the molecular mechanism of action of SPP is complicated by many factors, including uptake and metabolism, as well as activation of specific G-protein-coupled SPP receptors, known as the endothelial differentiation gene-1 (EDG-1) family. In this study, we overexpressed type 1 sphingosine kinase (SPHK1), the enzyme that converts sphingosine to SPP, in order to examine more directly the role of intracellularly generated SPP in neuronal survival. Enforced expression of SPHK1 in PC12 cells resulted in significant increases in kinase activity, with corresponding increases in intracellular SPP levels and concomitant decreases in both sphingosine and ceramide, and marked suppression of apoptosis induced by trophic factor withdrawal or by C(2)-ceramide. NGF, which protects PC12 cells from serum withdrawal-induced apoptosis, also stimulated SPHK1 activity. Surprisingly, overexpression of SPHK1 had no effect on activation of two known NGF-stimulated survival pathways, extracellular signal regulated kinase ERK 1/2 and Akt. However, trophic withdrawal-induced activation of the stress activated protein kinase, c-Jun amino terminal kinase (SAPK/JNK), and activation of the executionary caspases 2, 3 and 7, were markedly suppressed. Moreover, this abrogation of caspase activation, which was prevented by the SPHK inhibitor N,N-dimethylsphingosine, was not affected by pertussis toxin treatment, indicating that the cytoprotective effect was likely not mediated by binding of SPP to cell surface G(i)-coupled SPP receptors. In agreement, there was no detectable release of SPP into the culture medium, even after substantially increasing cellular SPP levels by NGF or sphingosine treatment. In contrast to PC12 cells, C6 astroglioma cells secreted SPP, suggesting that SPP might be one of a multitude of known neurotrophic factors produced and secreted by glial cells. Collectively, our results indicate that SPHK/SPP may play an important role in neuronal survival by regulating activation of SAPKs and caspases.
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Affiliation(s)
- L C Edsall
- Laboratory of Cellular and Molecular Regulation, NIMH, Bethesda, USA
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84
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Molina-Holgado E, Vela JM, Arévalo-Martín A, Guaza C. LPS/IFN-gamma cytotoxicity in oligodendroglial cells: role of nitric oxide and protection by the anti-inflammatory cytokine IL-10. Eur J Neurosci 2001; 13:493-502. [PMID: 11168556 DOI: 10.1046/j.0953-816x.2000.01412.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Proinflammatory mediators have been implicated in demyelinating disorders, including multiple sclerosis, whereas it has been proposed that the anti-inflammatory cytokines interleukin- (IL-) 4 and IL-10 participate in disease recovery. The present study analysed the effect of interferon-gamma (IFN-gamma) and bacterial endotoxin (lipopolysaccharide, LPS) on proliferation and survival of progenitors and differentiated oligodendrocytes. We also investigated the presence of receptors for IL-4 and IL-10 in oligodendroglial cells and explored a possible protective action of IL-4 and IL-10 in cultures following LPS/IFN-gamma. Finally, the role of endogenous nitric oxide (NO) on cell viability and the modulatory action of IL-4 and IL-10 on inducible nitric oxide synthase (iNOS) expression were also analysed. We report that LPS and/or IFN-gamma reduced proliferation and viability of oligodendroglial cells. Cell death, presumably by apoptosis as evidence by TUNEL and Annexin V binding, was observed following LPS/IFN-gamma, progenitors being more sensitive than differentiated cells. At both developmental stages, LPS/IFN-gamma-treated cultures expressed iNOS protein and released micromolar concentrations of NO. In progenitors, LPS/IFN-gamma-mediated cell damage was partially dependent on endogenous NO production, whereas NO was fundamental for cytotoxicity of differentiated oligodendrocytes. Both cell types expressed mRNA for IL-4 and IL-10 receptors and expression of IL-10 receptors at the protein level was also demonstrated. Treatment with either cytokine inhibited the expression of iNOS resulting from the proinflammatory stimulation. IL-10 was more effective than IL-4 in suppressing iNOS expression and, interestingly, IL-10 conferred protection against oligodendroglial death evoked by LPS/IFN-gamma. Our data raise the question of whether IL-10 may play a protective role in demyelinating diseases, not only downregulating the function of inflammatory cells but also promoting survival of progenitors and differentiated oligodendrocytes.
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Affiliation(s)
- E Molina-Holgado
- Neural Plasticity Unit, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avenida Doctor Arce 37, 28002 Madrid, Spain
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85
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Abstract
The availability of large amounts of sequence data has made it possible to identify death receptors by homology. Because the genome has not been analyzed completely, a few additional members of this family probably will be identified in the next few years. Rapid progress also has been made recently on the signaling mechanisms used by the death receptors. Considerable conservation of the intracellular signaling mechanisms is seen between different receptors suggesting that it is unlikely that new elements will be added to the molecular framework of death receptor signaling. The analysis of signaling mechanisms has exposed the complexity and multiplicity of cellular responses on death receptor activation. It is not surprising, therefore, that understanding the biological function the death receptors lags behind their characterization at the molecular level. In particular, the role of death receptors in many disease states, such as myocardial disease, remains to be elucidated. (38) This complexity in death-receptor function has constrained their potential for pharmacological manipulation. In most cases it is not sufficient to simply activate a specific death receptor. Manipulation of only one of the multiple responses induced by the receptor is desirable. Currently, no solutions to this challenge have been applied. The exception to this conundrum may be TRAIL. Injection of recombinant TRAIL has few side effects in animal studies and combination therapies that use TRAIL as a radiation sensitizer show early promise.
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Affiliation(s)
- C Vincenz
- Department of Pathology, University of Michigan Medical School, Ann Arbor 48109, USA.
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86
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Hisahara S, Yuan J, Momoi T, Okano H, Miura M. Caspase-11 mediates oligodendrocyte cell death and pathogenesis of autoimmune-mediated demyelination. J Exp Med 2001; 193:111-22. [PMID: 11136825 PMCID: PMC2195881 DOI: 10.1084/jem.193.1.111] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are inflammatory diseases of the central nervous system (CNS) characterized by localized areas of demyelination. The mechanisms underlying oligodendrocyte (OLG) injury in MS and EAE remain unknown. Here we show that caspase-11 plays crucial roles in OLG death and pathogenesis in EAE. Caspase-11 and activated caspase-3 were both expressed in OLGs in spinal cord EAE lesions. OLGs from caspase-11-deficient mice were highly resistant to the cell death induced by cytotoxic cytokines. EAE susceptibility and cytokine concentrations in the CNS were significantly reduced in caspase-11-deficient mice. Our findings suggest that OLG death is mediated by a pathway that involves caspases-11 and -3 and leads to the demyelination observed in EAE.
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MESH Headings
- Animals
- Apoptosis
- Base Sequence
- Caspase 3
- Caspases/deficiency
- Caspases/genetics
- Caspases/metabolism
- Caspases/physiology
- Caspases, Initiator
- DNA Primers/genetics
- Demyelinating Diseases/etiology
- Encephalomyelitis, Autoimmune, Experimental/enzymology
- Encephalomyelitis, Autoimmune, Experimental/etiology
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Enzyme Activation
- Female
- Humans
- Male
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Multiple Sclerosis/etiology
- Oligodendroglia/cytology
- Oligodendroglia/enzymology
- Oligodendroglia/immunology
- Pregnancy
- Spinal Cord/enzymology
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Affiliation(s)
- Shin Hisahara
- Division of Neuroanatomy, Department of Neuroscience, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Junying Yuan
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Takashi Momoi
- Division of Development and Differentiation, National Institute of Neuroscience, Tokyo 187-8502, Japan
| | - Hideyuki Okano
- Division of Neuroanatomy, Department of Neuroscience, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
- Core Research for Evolutional Science and Technology (CREST), Osaka 565-0871, Japan
| | - Masayuki Miura
- Division of Neuroanatomy, Department of Neuroscience, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
- Core Research for Evolutional Science and Technology (CREST), Osaka 565-0871, Japan
- Laboratory for Cell Recovery Mechanisms, Brain Science Institute, RIKEN, Saitama 351-0198, Japan
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87
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Park JA, Lee JY, Sato TA, Koh JY. Co-induction of p75NTR and p75NTR-associated death executor in neurons after zinc exposure in cortical culture or transient ischemia in the rat. J Neurosci 2000; 20:9096-103. [PMID: 11124986 PMCID: PMC6773028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Recently, a 22 kDa protein termed p75(NTR)-associated death executor (NADE) was discovered to be a necessary factor for p75(NTR)-mediated apoptosis in certain cells. However, the possible role for p75(NTR)/NADE in pathological neuronal death has yet been undetermined. In the present study, we have examined this possibility in vivo and in vitro. Exposure of cortical cultures to zinc induced both p75(NTR) and NADE in neurons, whereas exposure to NMDA, ionomycin, iron, or H(2)O(2) induced neither. In addition, zinc exposure increased neuronal NGF expression and its release into the medium. A function-blocking antibody of p75(NTR) (REX) inhibited association between p75(NTR) and NADE as well as neuronal death induced by zinc. Conversely, NGF augmented zinc-induced neuronal death. Caspase inhibitors reduced zinc-induced neuronal death, indicating that caspases were involved. Because reduction of NADE expression with cycloheximide or NADE antisense oligonucleotides attenuated zinc-induced neuronal death, NADE appears to contribute to p75(NTR)-induced cortical neuronal death as shown in other cells. Because zinc neurotoxicity may be a key mechanism of neuronal death after transient forebrain ischemia, we next examined this model. After ischemia, p75(NTR) and NADE were induced in degenerating rat hippocampal CA1 neurons. There was a close correlation between zinc accumulation and p75(NTR)/NADE induction. Suggesting the role of zinc here, injection of a metal chelator, CaEDTA, into the lateral ventricle completely blocked the induction of p75(NTR) and NADE. Our results suggest that co-induction of p75(NTR) and NADE plays a role in zinc-triggered neuronal death in vitro and in vivo.
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MESH Headings
- Animals
- Antibodies, Blocking/pharmacology
- Apoptosis/drug effects
- Apoptosis Regulatory Proteins
- Blotting, Western
- Caspase Inhibitors
- Cells, Cultured
- Cerebral Cortex/cytology
- Cerebral Cortex/drug effects
- Cerebral Cortex/metabolism
- Dose-Response Relationship, Drug
- Down-Regulation/drug effects
- Edetic Acid/pharmacology
- Gene Expression Regulation/drug effects
- Hippocampus/cytology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Ischemic Attack, Transient/metabolism
- Male
- Mice
- Nerve Growth Factor/metabolism
- Nerve Growth Factor/pharmacology
- Neurons/cytology
- Neurons/drug effects
- Neurons/metabolism
- Oligonucleotides, Antisense/pharmacology
- Protein Biosynthesis
- Protein Synthesis Inhibitors/pharmacology
- Proteins/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Nerve Growth Factor
- Receptors, Nerve Growth Factor/biosynthesis
- Signal Transduction/drug effects
- Zinc/pharmacology
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Affiliation(s)
- J A Park
- National Creative Research Initiative Center for the Study of CNS Zinc and Department of Neurology, University of Ulsan College of Medicine, 388-1 Poongnap-Dong Songpa-Gu, Seoul 138-736, Korea
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88
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Burgmaier G, Schönrock LM, Kuhlmann T, Richter-Landsberg C, Brück W. Association of increased bcl-2 expression with rescue from tumor necrosis factor-alpha-induced cell death in the oligodendrocyte cell line OLN-93. J Neurochem 2000; 75:2270-6. [PMID: 11080178 PMCID: PMC7166700 DOI: 10.1046/j.1471-4159.2000.0752270.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study investigated the effects of flupirtine (Katadolon) on tumor necrosis factor (TNF)-alpha-mediated cell death and Bcl-2 expression in the permanent rat oligodendrocyte cell line OLN-93 (OLN cells). TNF-alpha (500 U/ml) induced apoptosis of OLN cells, which was confirmed by DNA fragmentation using an in situ end-labeling technique and ultrastructural analysis. Flupirtine significantly reduced the rate of spontaneous cell death of OLN cells already at low concentrations; TNF-alpha-mediated apoptosis was suppressed only with higher concentrations of flupirtine (100 microM:). Expression of Bcl-2 protein and mRNA in OLN cells was detected by immunocytochemistry, western blot, and RT-PCR. Quantitative analysis of western blots revealed an approximately 2. 5-fold up-regulation of Bcl-2 protein during TNF-alpha treatment. Furthermore, addition of 10 or 100 microM: flupirtine before incubation with TNF-alpha led to an approximately threefold increase of Bcl-2 expression. Exposure of OLN cells to flupirtine alone moderately augmented the expression of Bcl-2 protein. Our data demonstrate that flupirtine up-regulates the expression of Bcl-2 protein in OLN cells; this Bcl-2 induction is associated with a reduced rate of TNF-alpha-induced cell death.
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Affiliation(s)
- G Burgmaier
- Department of Neuropathology, Georg-August-Universität Göttingen, Göttingen, Germany
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89
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Feigenbaum V, Gélot A, Casanova P, Daumas-Duport C, Aubourg P, Dubois-Dalcq M. Apoptosis in the central nervous system of cerebral adrenoleukodystrophy patients. Neurobiol Dis 2000; 7:600-12. [PMID: 11114259 DOI: 10.1006/nbdi.2000.0315] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The childhood cerebral form of adrenoleukodystrophy (ALD) is a fatal demyelinating disease, yet mice deficient in the ALD gene do not show such clinicopathological phenotype. We have therefore investigated in human autopsy tissues whether the ALD gene mutation results in apoptosis of CNS cells. Specimens from telencephalic and brainstem regions of four patients, and three controls were examined for internucleosomal DNA fragmentation, in situ detection of DNA breaks by the TUNEL method, and caspase-3 immunostaining. None of the controls showed significant apoptosis in white matter, while apoptotic nuclei with chromatin alterations were detected in areas of active demyelination in three ALD patients. A large proportion of apoptotic cells were oligodendrocytes and some express activated caspase-3. TUNEL-positive nuclei and/or caspase-3 staining were also detected in perivascular infiltrates and, occasionally, in neurons. We conclude that apoptosis of oligodendrocytes may account, at least in part, for the demyelinating process in the ALD brain.
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Affiliation(s)
- V Feigenbaum
- Unité de Neurovirologie et Regénération du Système Nerveux, Institut Pasteur, 25 rue du Dr Roux, Paris, 75015, France
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90
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Eggert A, Sieverts H, Ikegaki N, Brodeur GM. p75 mediated apoptosis in neuroblastoma cells is inhibited by expression of TrkA. MEDICAL AND PEDIATRIC ONCOLOGY 2000; 35:573-6. [PMID: 11107120 DOI: 10.1002/1096-911x(20001201)35:6<573::aid-mpo17>3.0.co;2-a] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Neurotrophins mediate their effects by binding to members of the Trk family of receptor tyrosine kinases and to the low-affinity nerve growth factor receptor p75. Nerve growth factor (NGF) has been demonstrated to support survival and differentiation of neuroblastoma (NB) cells by activation of the TrkA receptor. The p75 receptor belongs to the tumor necrosis factor (TNF) family of death receptors and has been suggested as a receptor that mediates apoptosis in neuronal and NB cells. PROCEDURE To investigate the effect of p75 expression in NB, we transfected the p75 cDNA into SH-SY5Y cells, an NB cell line lacking expression of both p75 and TrkA. RESULTS Cell clones expressing elevated levels of p75 showed a high degree of apoptosis even in 10% serum-supplemented medium. Apoptotic signaling by p75 was ligand-independent and only partly caspase-dependent. The level of apoptosis correlated directly with the expression level of the receptor, indicating that p75 may activate the cell death program directly. However, additional transfection of TrkA into SY5Y-p75 cells resulted in a significantly reduced rate of apoptosis even in the absence of NGF. CONCLUSIONS Thus, expression of the TrkA receptor itself inhibits p75 mediated apoptosis in NB cells.
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Affiliation(s)
- A Eggert
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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91
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Yamaoka T, Yoshino K, Yamada T, Idehara C, Hoque MO, Moritani M, Yoshimoto K, Hata J, Itakura M. Diabetes and tumor formation in transgenic mice expressing Reg I. Biochem Biophys Res Commun 2000; 278:368-76. [PMID: 11097844 DOI: 10.1006/bbrc.2000.3813] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
To examine the effect of overexpressed regenerating gene (Reg) I on pancreatic beta-cells, we generated transgenic mice expressing Reg I in islets (Reg-Tg mice). Three lines of Reg-Tg mice were established. In line-1 Reg-Tg mice, the expression level of Reg I mRNA in islets was 7 times higher than those in lines 2 and 3 of Reg-Tg mice, and line 1 mice developed diabetes by apoptosis of beta-cells, as well as various malignant tumors. In addition to the decrease in beta-cells, compensatory islet regeneration and proliferation of ductal epithelial cells were observed in line-1 Reg-Tg mice. Because Reg I protein was secreted primarily into pancreatic ducts from acinar cells, it may primarily stimulate the proliferation of ductal epithelial cells, and not beta-cells, and their differentiation into islets. Moreover, the tumor-promoting activity of Reg I protein should be considered for its possible clinical applications.
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Affiliation(s)
- T Yamaoka
- Division of Genetic Information, Institute for Genome Research, University of Tokushima, Japan.
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92
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Abstract
Apoptosis of neurons and glia contribute to the overall pathology of traumatic brain injury (TBI) in both humans and animals. In both head-injured humans and following experimental brain injury, apoptotic cells have been observed alongside degenerating cells exhibiting classic necrotic morphology. Neurons undergoing apoptosis have been identified within contusions in the acute port-traumatic period, and in regions remote from the site of impact in the days and weeks after trauma. Apoptotic oligodendrocytes and astrocytes have been observed within injured white matter tracts. We review the regional and temporal patterns of apoptosis following TBI and the possible mechanisms underlying trauma-induced apoptosis. While excitatory amino acids, increases in intracellular calcium, and free radicals can all cause cells to undergo apoptosis, in vitro studies have determined that neural cells can undergo apoptosis via many other pathways. It is generally accepted that a shift in the balance between pro- and anti-apoptotic protein factors towards the expression of proteins that promote death may be one mechanism underlying apoptotic cell death. The effect of TBI on regional cellular patterns of expression of survival promoting-proteins such as Bcl-2, Bcl-xL, and extracellular signal regulated kinases, and death-inducing proteins such as Bax, c-Jun N-terminal kinase, tumor-suppressor gene, p53, and the caspase family of proteases are reviewed. Finally, in light of pharmacologic strategies that have been devised to reduce the extent of apoptotic cell death in animal models of TBI, our review also considers whether apoptosis may serve a protective role in the injured brain.
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Affiliation(s)
- R Raghupathi
- Department of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
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93
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Wang S, Bray P, McCaffrey T, March K, Hempstead BL, Kraemer R. p75(NTR) mediates neurotrophin-induced apoptosis of vascular smooth muscle cells. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 157:1247-58. [PMID: 11021829 PMCID: PMC1850174 DOI: 10.1016/s0002-9440(10)64640-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The development of atherosclerotic lesions results from aberrant cell migration, proliferation, and extracellular matrix production. In advanced lesions, however, cellular apoptosis, leading to lesion remodeling, predominates. During lesion formation, the neurotrophins and the neurotrophin receptor tyrosine kinases, trks B and C, are induced and mediate smooth muscle cell migration. Here we demonstrate that a second neurotrophin receptor, p75(NTR), is expressed by established human atherosclerotic lesions and late lesions that develop after balloon injury of the rat thoracic aorta. The p75(NTR), a member of the tumor necrosis factor/FAS receptor family, can modulate trk receptor function as well as initiate cell death when expressed in cells of the nervous system that lack kinase-active trk receptors. p75(NTR) expression colocalizes to neointimal cells, which express smooth muscle cell alpha-actin and are expressed by cultured human endarterectomy-derived cells (HEDC). Areas of the plaque expressing p75(NTR) demonstrate increased TUNEL positivity, and HEDC undergo apoptosis in response to the neurotrophins. Finally, neurotrophins also induced apoptosis of a smooth muscle cell line genetically manipulated to express p75(NTR), but lacking trk receptor expression. These studies identify the regulated expression of neurotrophins and p75(NTR) as an inducer of smooth muscle cell apoptosis in atherosclerotic lesions.
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MESH Headings
- Animals
- Apoptosis/physiology
- Arteriosclerosis/pathology
- Arteriosclerosis/physiopathology
- Cells, Cultured
- Humans
- In Situ Nick-End Labeling
- Male
- Mice
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiology
- Nerve Growth Factors/pharmacology
- Polysaccharides/physiology
- Rats
- Rats, Sprague-Dawley
- Receptor, Nerve Growth Factor/metabolism
- Receptor, Nerve Growth Factor/physiology
- Temperature
- Tissue Distribution
- Tunica Intima/metabolism
- Tunica Intima/pathology
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Affiliation(s)
- S Wang
- Departments of Pathology and Medicine, Joan and Sanford I. Weill Medical College of Cornell University, New York, New York, USA
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94
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Coulson EJ, Reid K, Baca M, Shipham KA, Hulett SM, Kilpatrick TJ, Bartlett PF. Chopper, a new death domain of the p75 neurotrophin receptor that mediates rapid neuronal cell death. J Biol Chem 2000; 275:30537-45. [PMID: 10882742 DOI: 10.1074/jbc.m005214200] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The cytoplasmic juxtamembrane region of the p75 neurotrophin receptor (p75(NTR)) has been found to be necessary and sufficient to initiate neural cell death. The region was named "Chopper" to distinguish it from CD95-like death domains. A 29-amino acid peptide corresponding to the Chopper region induced caspase- and calpain-mediated death in a variety of neural and non-neural cell types and was not inhibited by signaling through Trk (unlike killing by full-length p75(NTR)). Chopper triggered cell death only when bound to the plasma membrane by a lipid anchor, whereas non-anchored Chopper acted in a dominant-negative manner, blocking p75(NTR)-mediated death both in vitro and in vivo. Removal of the ectodomain of p75(NTR) increased the potency of Chopper activity, suggesting that it regulates the association of Chopper with downstream signaling proteins.
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Affiliation(s)
- E J Coulson
- Walter and Eliza Hall Institute of Medical Research, Post Office, Royal Melbourne Hospital, Victoria 3050, Australia.
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95
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Shibata M, Hisahara S, Hara H, Yamawaki T, Fukuuchi Y, Yuan J, Okano H, Miura M. Caspases determine the vulnerability of oligodendrocytes in the ischemic brain. J Clin Invest 2000; 106:643-53. [PMID: 10974017 PMCID: PMC381288 DOI: 10.1172/jci10203] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Although oligodendrocytes (OLGs) are thought to be vulnerable to hypoxia and ischemia, little is known about the detailed mechanism by which these insults induce OLG death. From the clinical viewpoint, it is imperative to protect OLGs as well as neurons against ischemic injury (stroke), because they are the only myelin-forming cells of the central nervous system. Using the Cre/loxP system, we have established a transgenic mouse line that selectively expresses p35, a broad-spectrum caspase inhibitor, in OLGs. After hypoxia, cultured OLGs derived from wild-type mice exhibited significant upregulation of caspase-11 and substantial activation of caspase-3, which led to cell loss. Expression of p35 or elimination of caspase-11 suppressed the caspase-3 activation and conferred significant protection against hypoxic injury. Expression of p35 in OLGs in vivo resulted in significant protection from ischemia-induced cell injury, thus indicating that caspases are involved in the ischemia-induced cell death of OLGs. Furthermore, the induction of caspase-11 was evident in the ischemic brains of wild-type mice, and OLGs exhibited resistance to brain ischemia in mice deficient in caspase-11, suggesting that caspase-11 is critically implicated in the mechanism(s) underlying ischemia-induced OLG death. Caspases may therefore offer a good therapeutic target for reducing ischemia-induced damage to OLGs.
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Affiliation(s)
- M Shibata
- Division of Neuroanatomy, Osaka University Graduate School of Medicine, Osaka, Japan.
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96
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Beer R, Franz G, Srinivasan A, Hayes RL, Pike BR, Newcomb JK, Zhao X, Schmutzhard E, Poewe W, Kampfl A. Temporal profile and cell subtype distribution of activated caspase-3 following experimental traumatic brain injury. J Neurochem 2000; 75:1264-73. [PMID: 10936210 DOI: 10.1046/j.1471-4159.2000.0751264.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This study investigated the temporal expression and cell subtype distribution of activated caspase-3 following cortical impact-induced traumatic brain injury in rats. The animals were killed and examined for protein expression of the proteolytically active subunit of caspase-3, p18, at intervals from 6 h to 14 days after injury. In addition, we also investigated the effect of caspase-3 activation on proteolysis of the cytoskeletal protein alpha-spectrin. Increased protein levels of p18 and the caspase-3-specific 120-kDa breakdown product to alpha-spectrin were seen in the cortex ipsilateral to the injury site from 6 to 72 h after the trauma. Immunohistological examinations revealed increased expression of p18 in neurons, astrocytes, and oligodendrocytes from 6 to 72 h following impact injury. In contrast, no evidence of caspase-3 activation was seen in microglia at all time points investigated. Quantitative analysis of caspase-3-positive cells revealed that the number of caspase-3-positive neurons exceeded the number of caspase-3-positive glia cells from 6 to 72 h after injury. Moreover, concurrent assessment of nuclear histopathology using hematoxylin identified p18-immunopositive cells exhibiting apoptotic-like morphological profiles in the cortex ipsilateral to the injury site. In contrast, no evidence of increased p18 expression or alpha-spectrin proteolysis was seen in the ipsilateral hippocampus, contralateral cortex, or hippocampus up to 14 days after the impact. Our results are the first to demonstrate the concurrent expression of activated caspase-3 in different CNS cells after traumatic brain injury in the rat. Our findings also suggest a contributory role of activated caspase-3 in neuronal and glial apoptotic degeneration after experimental TBI in vivo.
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Affiliation(s)
- R Beer
- Department of Neurology, University Hospital Innsbruck, Austria
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97
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Agerman K, Baudet C, Fundin B, Willson C, Ernfors P. Attenuation of a caspase-3 dependent cell death in NT4- and p75-deficient embryonic sensory neurons. Mol Cell Neurosci 2000; 16:258-68. [PMID: 10995552 DOI: 10.1006/mcne.2000.0875] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Neuronal survival during the developmental period of naturally occurring cell death is mediated through a successful competition for limiting concentrations of neurotrophic factors, and the deprived neurons will die. New results show that induced death through the p75 neurotrophin receptor (p75(NTR)), a member of the p55TNF/Fas family of cell death receptors, may also influence survival during development. We find that eliminating p75(NTR) or neurotrophin 4 (NT4) in mice leads to a marked attenuation of apoptosis during the programmed cell death period of the trigeminal ganglion neurons, suggesting that NT4 can induce the death of these neurons through the p75(NTR). These in vivo findings were reproduced in primary cell cultures, where NT4 was found to induce death in a p75(NTR)-dependent pathway. Analysis of p75 deficient and wild-type cells revealed two separate cell death pathways, a p75(NTR)- and caspase-3-independent pathway activated by trophic factor deprivation, and a p75(NTR)- and caspase-3-dependent pathway initiated by NT4. Crossing in the NT4 null alleles in brain-derived neurotrophic factor (BDNF) null mutant mice led to a rescue of a large proportion of BDNF-dependent neurons from excessive cell death, indicating that trophic factor deprivation is not sufficient for the death of many neurons and that additional death inducing signals might be required. Our results suggest that NT4 competitively signals survival and death of sensory neurons through trkB and p75(NTR), respectively.
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Affiliation(s)
- K Agerman
- Department of Medical Biochemistry and Biophysics, Laboratory of Molecular Neurobiology, Berzeliusv. 3, Karolinska Institutet, Stockholm, 171 77, Sweden
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98
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Syroid DE, Maycox PJ, Soilu-Hänninen M, Petratos S, Bucci T, Burrola P, Murray S, Cheema S, Lee KF, Lemke G, Kilpatrick TJ. Induction of postnatal schwann cell death by the low-affinity neurotrophin receptor in vitro and after axotomy. J Neurosci 2000; 20:5741-7. [PMID: 10908614 PMCID: PMC6772552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Schwann cells express the low-affinity neurotrophin receptor (p75), but no role for either the neurotrophins or their cognate receptors in Schwann cell development has been established. We have found that Schwann cells isolated from postnatal day 1 (P1) or P2 mice that were p75-deficient exhibited potentiated survival compared to wild-type cells after growth factor and serum withdrawal. There was, however, no disparity in the survival of p75-deficient and wild-type Schwann cells isolated at embryonic day 15, suggesting that the death-inducing effects of p75 are developmentally regulated. A comparable degree of cell death was also observed in the sciatic nerves of both wild-type and p75-deficient mice at P1. However, 24 hr after axotomy, there was a 13-fold increase in the percentage of apoptotic nuclei in the distal nerve stumps of the transected sciatic nerves of neonatal wild-type but not p75-deficient mice. The expression of both the p75 and nerve growth factor (NGF) genes was upregulated after axotomy in neonatal wild-type nerves. Collectively, these results suggest that NGF-mediated activation of p75 is likely to be an important mediator of Schwann cell apoptosis in the context of peripheral nerve injury.
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Affiliation(s)
- D E Syroid
- The Walter and Eliza Hall Institute of Medical Research, The Royal Melbourne Hospital, Victoria, Australia
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99
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Gu C, Ma YC, Benjamin J, Littman D, Chao MV, Huang XY. Apoptotic signaling through the beta -adrenergic receptor. A new Gs effector pathway. J Biol Chem 2000; 275:20726-33. [PMID: 10767282 DOI: 10.1074/jbc.m000152200] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stimulation of beta-adrenergic receptor normally results in signaling by the heterotrimeric G protein G(s), leading to the activation of adenylyl cyclase, production of cAMP, and activation of cAMP-dependent protein kinase (PKA). Here we report that cell death of thymocytes can be induced after stimulation of beta-adrenergic receptor, or by addition of exogenous cAMP. Apoptotic cell death in both cases was observed with the appearance of terminal deoxynucleotidyl transferase-mediated UTP end labeling reactivity and the activation of caspase-3 in S49 T cells. Using thymocytes deficient in either Galpha(s) or PKA, we find that engagement of beta-adrenergic receptors initiated a Galpha(s)-dependent, PKA-independent pathway leading to apoptosis. This alternative pathway involves Src family tyrosine kinase Lck. Furthermore, we show that Lck protein kinase activity can be directly stimulated by purified Galpha(s). Our data reveal a new signaling pathway for Galpha(s), distinct from the classical PKA pathway, that accounts for the apoptotic action of beta-adrenergic receptors.
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Affiliation(s)
- C Gu
- Graduate Program of Cell Biology and Genetics, Graduate Program of Physiology, Biophysics and Molecular Medicine, and the Department of Physiology, Cornell University Medical College, New York, New York 10021, USA
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100
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Kavanaugh B, Beesley J, Itoh T, Itoh A, Grinspan J, Pleasure D. Neurotrophin-3 (NT-3) diminishes susceptibility of the oligodendroglial lineage to AMPA glutamate receptor-mediated excitotoxicity. J Neurosci Res 2000; 60:725-32. [PMID: 10861784 DOI: 10.1002/1097-4547(20000615)60:6<725::aid-jnr4>3.0.co;2-v] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Prior reports demonstrated that cells of the oligodendroglial lineage are susceptible to excitotoxic necrosis mediated by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid glutamate receptors (AMPA-GluR), and also showed that these cells express the high affinity neurotrophin receptors, TrkC and TrkA. We now report that: a) oligodendroglial progenitors (OP) and immature oligodendroglia are more vulnerable to AMPA-GluR-mediated excitotoxicity than are mature oligodendroglia; b) TrkC expression falls substantially during differentiation of cultured OP to mature oligodendroglia, whereas TrkA expression increases markedly; and c) neurotrophin-3, and to a lesser extent, nerve growth factor, protect the oligodendroglial lineage against AMPA-GluR-mediated excitotoxicity.
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Affiliation(s)
- B Kavanaugh
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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