101
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Rodrigues R, Petersen RB, Perry G. Parallels between major depressive disorder and Alzheimer's disease: role of oxidative stress and genetic vulnerability. Cell Mol Neurobiol 2014; 34:925-49. [PMID: 24927694 DOI: 10.1007/s10571-014-0074-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 05/14/2014] [Indexed: 12/19/2022]
Abstract
The thesis of this review is that oxidative stress is the central factor in major depressive disorder (MDD) and Alzheimer's disease (AD). The major elements involved are inflammatory cytokines, the hypothalamic-pituitary axis, the hypothalamic-pituitary gonadal, and arginine vasopressin systems, which induce glucocorticoid and "oxidopamatergic" cascades when triggered by psychosocial stress, severe life-threatening events, and mental-affective and somatic diseases. In individuals with a genomic vulnerability to depression, these cascades may result in chronic depression-anxiety-stress spectra, resulting in MDD and other known depressive syndromes. In contrast, in subjects with genomic vulnerability to AD, oxidative stress-induced brain damage triggers specific antioxidant defenses, i.e., increased levels of amyloid-β (Aβ) and aggregation of hyper-phosphorylated tau, resulting in paired helical filaments and impaired functions related to the ApoEε4 isoform, leading to complex pathological cascades culminating in AD. Surprisingly, all the AD-associated molecular pathways mentioned in this review have been shown to be similar or analogous to those found in depression, including structural damage, i.e., hippocampal and frontal cortex atrophy. Other interacting molecular signals, i.e., GSK-3β, convergent survival factors (brain-derived neurotrophic factor and heat shock proteins), and transition redox metals are also mentioned to emphasize the vast array of intermediates that could interact via comparable mechanisms in both MDD and AD.
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Affiliation(s)
- Roberto Rodrigues
- College of Sciences, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA,
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102
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Cognitive flexibility and long-term depression (LTD) are impaired following β-catenin stabilization in vivo. Proc Natl Acad Sci U S A 2014; 111:8631-6. [PMID: 24912177 DOI: 10.1073/pnas.1404670111] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cadherin/β-catenin adhesion complex is a key mediator of the bidirectional changes in synapse strength which are believed to underlie complex learning and memory. In the present study, we demonstrate that stabilization of β-catenin in the hippocampus of adult mice results in significant impairments in cognitive flexibility and spatial reversal learning, including impaired extinction during the reversal phase of the Morris water maze and deficits in a delayed nonmatch to place T-maze task. In accordance with these deficits, β-catenin stabilization was found to abolish long-term depression by stabilizing cadherin at the synaptic membrane and impairing AMPA receptor endocytosis, while leaving basal synaptic transmission and long-term potentiation unaffected. These results demonstrate that the β-catenin/cadherin adhesion complex plays an important role in learning and memory and that aberrant increases in synaptic adhesion can have deleterious effects on cognitive function.
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103
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Expression of S100A6 in rat hippocampus after traumatic brain injury due to lateral head acceleration. Int J Mol Sci 2014; 15:6378-90. [PMID: 24739809 PMCID: PMC4013634 DOI: 10.3390/ijms15046378] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 03/25/2014] [Accepted: 03/31/2014] [Indexed: 12/14/2022] Open
Abstract
In a rat model of traumatic brain injury (TBI), we investigated changes in cognitive function and S100A6 expression in the hippocampus. TBI-associated changes in this protein have not previously been reported. Rat S100A6 was studied via immunohistochemical staining, Western blot, and reverse transcription-polymerase chain reaction (RT-PCR) after either lateral head acceleration or sham. Reduced levels of S100A6 protein and mRNA were observed 1 h after TBI, followed by gradual increases over 6, 12, 24, and 72 h, and then a return to sham level at 14 day. Morris water maze (MWM) test was used to evaluate animal spatial cognition. TBI- and sham-rats showed an apparent learning curve, expressed as escape latency. Although TBI-rats displayed a relatively poorer cognitive ability than sham-rats, the disparity was not significant early post-injury. Marked cognitive deficits in TBI-rats were observed at 72 h post-injury compared with sham animals. TBI-rats showed decreased times in platform crossing in the daily MWM test; the performance at 72 h post-injury was the worst. In conclusion, a reduction in S100A6 may be one of the early events that lead to secondary cognitive decline after TBI, and its subsequent elevation is tightly linked with cognitive improvement. S100A6 may play important roles in neuronal degeneration and regeneration in TBI.
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104
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Bonda DJ, Wang X, Lee HG, Smith MA, Perry G, Zhu X. Neuronal failure in Alzheimer's disease: a view through the oxidative stress looking-glass. Neurosci Bull 2014; 30:243-52. [PMID: 24733654 DOI: 10.1007/s12264-013-1424-x] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 02/17/2014] [Indexed: 11/24/2022] Open
Abstract
Considerable debate and controversy surround the cause(s) of Alzheimer's disease (AD). To date, several theories have gained notoriety, however none is universally accepted. In this review, we provide evidence for the oxidative stress-induced AD cascade that posits aged mitochondria as the critical origin of neurodegeneration in AD.
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Affiliation(s)
- David J Bonda
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
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105
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Meffre D, Grenier J, Bernard S, Courtin F, Dudev T, Shackleford G, Jafarian-Tehrani M, Massaad C. Wnt and lithium: a common destiny in the therapy of nervous system pathologies? Cell Mol Life Sci 2014; 71:1123-48. [PMID: 23749084 PMCID: PMC11113114 DOI: 10.1007/s00018-013-1378-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/26/2013] [Accepted: 05/16/2013] [Indexed: 02/07/2023]
Abstract
Wnt signaling is required for neurogenesis, the fate of neural progenitors, the formation of neuronal circuits during development, neuron positioning and polarization, axon and dendrite development and finally for synaptogenesis. This signaling pathway is also implicated in the generation and differentiation of glial cells. In this review, we describe the mechanisms of action of Wnt signaling pathways and their implication in the development and correct functioning of the nervous system. We also illustrate how a dysregulated Wnt pathway could lead to psychiatric, neurodegenerative and demyelinating pathologies. Lithium, used for the treatment of bipolar disease, inhibits GSK3β, a central enzyme of the Wnt/β-catenin pathway. Thus, lithium could, to some extent, mimic Wnt pathway. We highlight the possible dialogue between lithium therapy and modulation of Wnt pathway in the treatment of the diseases of the nervous system.
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Affiliation(s)
- Delphine Meffre
- UMR 8194 CNRS, University Paris Descartes, 45 rue des Saints-Pères, 75270 Paris Cedex 6, France
| | - Julien Grenier
- UMR 8194 CNRS, University Paris Descartes, 45 rue des Saints-Pères, 75270 Paris Cedex 6, France
| | - Sophie Bernard
- UMR 8194 CNRS, University Paris Descartes, 45 rue des Saints-Pères, 75270 Paris Cedex 6, France
| | - Françoise Courtin
- UMR 8194 CNRS, University Paris Descartes, 45 rue des Saints-Pères, 75270 Paris Cedex 6, France
| | - Todor Dudev
- Institute of Biomedical Sciences, Academia Sinica, 11529 Taipei, Taiwan, R.O.C
- Faculty of Chemistry and Pharmacy, University of Sofia, 1 James Bourchier Avenue, 1164 Sofia, Bulgaria
| | | | | | - Charbel Massaad
- UMR 8194 CNRS, University Paris Descartes, 45 rue des Saints-Pères, 75270 Paris Cedex 6, France
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106
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Tau hyperphosphorylation induces apoptotic escape and triggers neurodegeneration in Alzheimer's disease. Neurosci Bull 2014; 30:359-66. [PMID: 24627329 DOI: 10.1007/s12264-013-1415-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 01/27/2014] [Indexed: 12/18/2022] Open
Abstract
Since abnormal post-translational modifications or gene mutations of tau have been detected in over twenty neurodegenerative disorders, tau has attracted widespread interest as a target protein. Among its various post-translational modifications, phosphorylation is the most extensively studied. It is recognized that tau hyperphosphorylation is the root cause of neurodegeneration in Alzheimer's disease (AD); however, it is not clear how it causes neurodegeneration. Based on the findings that tau hyperphosphorylation leads to the escape of neurons from acute apoptosis and simultaneously impairs the function of neurons, we have proposed that the nature of AD neurodegeneration is the consequence of aborted apoptosis induced by tau phosphorylation. Therefore, proper manipulation of tau hyperphosphorylation could be promising for arresting AD neurodegeneration. In this review, the neuroprotective and neurodegenerative effects of tau hyperphosphorylation and our thoughts regarding their relationship are presented.
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107
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Chao J, Yang L, Yao H, Buch S. Platelet-derived growth factor-BB restores HIV Tat -mediated impairment of neurogenesis: role of GSK-3β/β-catenin. J Neuroimmune Pharmacol 2014; 9:259-68. [PMID: 24248537 PMCID: PMC4183349 DOI: 10.1007/s11481-013-9509-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 10/14/2013] [Indexed: 12/25/2022]
Abstract
Our previous study demonstrated that platelet-derived growth factor-BB (PDGF-BB) increased the cell proliferation of primary rat neuronal progenitor cells (NPCs). However, whether PDGF-BB regulates neurogenesis in HIV-associated neurological disorder (HAND) remains largely unknown. In this study we demonstrated that pre-treatment of NPCs with PDGF-BB restored Tat-mediated impairment of cell proliferation via activation of p38 and JNK MAPK pathways. Moreover, treatment with PDGF-BB induced inactivation of glycogen synthase kinase-3β (GSK-3β), evidenced by its phosphorylation at Ser9, this effect was significantly inhibited by the p38 and JNK inhibitors. Level of nuclear β-catenin, the primary substrate of GSK-3β, was also concomitantly increased following PDGF-BB treatment, suggesting that PDGF-BB stimulates NPC proliferation via acting on GSK-3β to promote nuclear accumulation of β-catenin. This was further validated by gain and loss of function studies using cells transfected with either the wild type or mutant GSK-3β constructs. Together these data underpin the role of GSK-3β/β-catenin as a novel target that regulates NPC proliferation mediated by PDGF-BB with implications for therapeutic intervention for reversal of impaired neurogenesis inflicted by Tat.
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Affiliation(s)
- Jie Chao
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center (DRC 8011), University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
| | - Lu Yang
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center (DRC 8011), University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
| | - Honghong Yao
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center (DRC 8011), University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, 985880 Nebraska Medical Center (DRC 8011), University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
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108
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L'Episcopo F, Tirolo C, Caniglia S, Testa N, Morale MC, Serapide MF, Pluchino S, Marchetti B. Targeting Wnt signaling at the neuroimmune interface for dopaminergic neuroprotection/repair in Parkinson's disease. J Mol Cell Biol 2014; 6:13-26. [PMID: 24431301 DOI: 10.1093/jmcb/mjt053] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
During the past three decades, the Wingless-type MMTV integration site (Wnt) signaling cascade has emerged as an essential system regulating multiple processes in developing and adult brain. Accumulating evidence points to a dysregulation of Wnt signaling in major neurodegenerative pathologies including Parkinson's disease (PD), a common neurodegenerative disorder characterized by the progressive loss of midbrain dopaminergic (mDA) neurons and deregulated activation of astrocytes and microglia. This review highlights the emerging link between Wnt signaling and key inflammatory pathways during mDA neuron damage/repair in PD progression. In particular, we summarize recent evidence documenting that aging and neurotoxicant exposure strongly antagonize Wnt/β-catenin signaling in mDA neurons and subventricular zone (SVZ) neuroprogenitors via astrocyte-microglial interactions. Dysregulation of the crosstalk between Wnt/β-catenin signaling and anti-oxidant/anti-inflammatory pathways delineate novel mechanisms driving the decline of SVZ plasticity with age and the limited nigrostriatal dopaminergic self-repair in PD. These findings hold a promise in developing therapies that target Wnt/β-catenin signaling to enhance endogenous restoration and neuronal outcome in age-dependent diseases, such as PD.
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Affiliation(s)
- Francesca L'Episcopo
- OASI Institute for Research and Care on Mental Retardation and Brain Aging (IRCCS), Neuropharmacology Section, Via Conte Ruggero 73, 94018 Troina, Italy
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109
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Iqbal K, Gong CX, Liu F. Microtubule-associated protein tau as a therapeutic target in Alzheimer's disease. Expert Opin Ther Targets 2014; 18:307-18. [PMID: 24387228 DOI: 10.1517/14728222.2014.870156] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Alzheimer's disease (AD) is a major public health problem in modern society and as yet, other than a few symptomatic drugs, there is no disease-modifying treatment for this disease available. AREAS COVERED Neurofibrillary pathology, which is made up from abnormally hyperphosphorylated microtubule-associated protein tau, is both a hallmark and key lesion of AD and related tauopathies. The density of neurofibrillary pathology in the cerebral cortex correlates with the degree of dementia. Both experimental and transgenic animal studies have consistently shown that abnormal hyperphosphorylation of tau causes cognitive impairment. Abnormal hyperphosphorylation of tau converts it from a microtubule assembly-promoting to a microtubule-disrupting protein and promotes its self-assembly into paired helical filaments. To date, the bulk of studies have shown that abnormal hyperphosphorylation is the key gain of toxic function step though some cell culture and transgenic mouse studies have also reported that aggregated tau can lead to neurodegeneration. In this article, we have reviewed data from our lab and that from PubMed search on the molecular mechanism of tau pathology and the potential of tau as a therapeutic target for AD and related disorders. EXPERT OPINION In our opinion, inhibition of abnormal hyperphosphorylation of tau is the most rational therapeutic target. Therapeutic approaches include restoration of the activity of protein phosphatase-2A, which is the major regulator of tau phosphorylation and the activity of which is compromised in AD brain, inhibition of one or more tau protein kinases which include GSK-3β, cyclin-dependent protein kinase-5, dual-specificity tyrosine phosphorylated-regulated kinase 1A, Ca(2+)/calmodulin-activated protein kinase II and casein kinase I, enhancement of O-GlcNAcylation of tau, and tau immunization.
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Affiliation(s)
- Khalid Iqbal
- New York State Institute for Basic Research in Developmental Disabilities, Department of Neurochemistry, Inge Grundke-Iqbal Research Floor , 1050 Forest Hill Road, Staten Island, NY 10314 , USA +1 718 494 5259 ;
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110
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Hyperphosphorylation of tau protein in the ipsilateral thalamus after focal cortical infarction in rats. Brain Res 2014; 1543:280-9. [DOI: 10.1016/j.brainres.2013.11.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/29/2013] [Accepted: 11/01/2013] [Indexed: 11/24/2022]
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111
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Oliva CA, Vargas JY, Inestrosa NC. Wnts in adult brain: from synaptic plasticity to cognitive deficiencies. Front Cell Neurosci 2013; 7:224. [PMID: 24348327 PMCID: PMC3847898 DOI: 10.3389/fncel.2013.00224] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 11/03/2013] [Indexed: 01/21/2023] Open
Abstract
During development of the central nervous system the Wnt signaling pathway has been implicated in a wide spectrum of physiological processes, including neuronal connectivity and synapse formation. Wnt proteins and components of the Wnt pathway are expressed in the brain since early development to the adult life, however, little is known about its role in mature synapses. Here, we review evidences indicating that Wnt proteins participate in the remodeling of pre- and post-synaptic regions, thus modulating synaptic function. We include the most recent data in the literature showing that Wnts are constantly released in the brain to maintain the basal neural activity. Also, we review the evidences that involve components of the Wnt pathway in the development of neurological and mental disorders, including a special emphasis on in vivo studies that relate behavioral abnormalities to deficiencies in Wnt signaling. Finally, we include the evidences that support a neuroprotective role of Wnt proteins in Alzheimer’s disease. We postulate that deregulation in Wnt signaling might have a fundamental role in the origin of neurological diseases, by altering the synaptic function at stages where the phenotype is not yet established but when the cognitive decline starts.
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Affiliation(s)
- Carolina A Oliva
- Centro de Envejecimiento y Regeneración, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile ; Departamento de Biologïa Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Jessica Y Vargas
- Centro de Envejecimiento y Regeneración, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile ; Departamento de Biologïa Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile ; Departamento de Biologïa Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile
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112
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Wang L, Jiang Q, Chu J, Lin L, Li XG, Chai GS, Wang Q, Wang JZ, Tian Q. Expression of Tau40 induces activation of cultured rat microglial cells. PLoS One 2013; 8:e76057. [PMID: 24146816 PMCID: PMC3795725 DOI: 10.1371/journal.pone.0076057] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 08/20/2013] [Indexed: 12/13/2022] Open
Abstract
Accumulation of microtubule-associated protein tau has been observed in the brain of aging and tauopathies. Tau was observed in microglia, but its role is not illustrated. By immunofluorescence staining and the fractal dimension value assay in the present study, we observed that microglia were activated in the brains of rats and mice during aging, simultaneously, the immunoreactivities of total tau and the phosphorylated tau were significantly enhanced in the activated microglia. Furtherly by transient transfection of tau40 (human 2N/4R tau) into the cultured rat microglia, we demonstrated that expression of tau40 increased the level of Iba1, indicating activation of microglia. Moreover, expression of tau40 significantly enhanced the membranous localization of the phosphorylated tau at Ser396 in microglia possibly by a mechanism involving protein phosphatase 2A, extracellular signal-regulated kinase and glycogen synthase kinase-3β. It was also found that expression of tau40 promoted microglial migration and phagocytosis, but not proliferation. And we observed increased secretion of several cytokines, including interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor-α and nitric oxide after the expression of tau40. These data suggest a novel role of human 2N/4R tau in microglial activation.
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Affiliation(s)
- Lu Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, China
| | - Qian Jiang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiang Chu
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Li Lin
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiao-Guang Li
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gao-Shang Chai
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qun Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- * E-mail: (JZW); (QT)
| | - Qing Tian
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- * E-mail: (JZW); (QT)
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113
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Morozova OA, March ZM, Robinson AS, Colby DW. Conformational features of tau fibrils from Alzheimer's disease brain are faithfully propagated by unmodified recombinant protein. Biochemistry 2013; 52:6960-7. [PMID: 24033133 DOI: 10.1021/bi400866w] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Fibrils composed of tau protein are a pathological hallmark of several neurodegenerative disorders including Alzheimer's disease (AD). Here we show that when recombinant tau protein is seeded with paired helical filaments (PHFs) isolated from AD brain, the amyloid formed shares many of the structural features of AD PHFs. In contrast, tau amyloids formed with heparin as an inducing agent-a common biochemical model of tau misfolding-are structurally distinct from brain-derived PHFs. Using ultrastructural analysis by electron microscopy, circular dichroism, and chemical denaturation, we found that AD seeded recombinant tau fibrils were not significantly different than tau fibrils isolated from AD brain tissue. Tau fibrils produced by incubating recombinant tau with heparin had significantly narrower fibrils with a longer periodicity, higher chemical stability, and distinct secondary structure compared to AD PHFs. The addition of heparin to the reaction of recombinant tau and AD PHFs also corrupted the templating process, resulting in a mixture of fibril conformations. Our results suggest that AD-isolated PHFs act as a conformational template for the formation of recombinant tau fibrils. Therefore, the use of AD PHFs as seeds to stimulate recombinant tau amyloid formation produces synthetic tau fibers that closely resemble those associated with AD pathology and provides a biochemical model of tau misfolding that may be of improved utility for structural studies and drug screening. These results also demonstrate that post-translational modifications such as phosphorylation are not a prerequisite for the propagation of the tau fibril conformation found in AD.
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Affiliation(s)
- Olga A Morozova
- Department of Chemical and Biomolecular Engineering, University of Delaware , Newark, Delaware 19716, United States
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114
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Rosso SB, Inestrosa NC. WNT signaling in neuronal maturation and synaptogenesis. Front Cell Neurosci 2013; 7:103. [PMID: 23847469 PMCID: PMC3701138 DOI: 10.3389/fncel.2013.00103] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 06/12/2013] [Indexed: 01/01/2023] Open
Abstract
The Wnt signaling pathway plays a role in the development of the central nervous system and growing evidence indicates that Wnts also regulates the structure and function of the adult nervous system. Wnt components are key regulators of a variety of developmental processes, including embryonic patterning, cell specification, and cell polarity. In the nervous system, Wnt signaling also regulates the formation and function of neuronal circuits by controlling neuronal differentiation, axon outgrowth and guidance, dendrite development, synaptic function, and neuronal plasticity. Wnt factors can signal through three very well characterized cascades: canonical or β-catenin pathway, planar cell polarity pathway and calcium pathway that control different processes. However, divergent downstream cascades have been identified to control neuronal morphogenesis. In the nervous system, the expression of Wnt proteins is a highly controlled process. In addition, deregulation of Wnt signaling has been associated with neurodegenerative diseases. Here, we will review different aspects of neuronal and dendrite maturation, including spinogenesis and synaptogenesis. Finally, the role of Wnt pathway components on Alzheimer’s disease will be revised.
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Affiliation(s)
- Silvana B Rosso
- Laboratorio de Toxicología Experimental, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario Rosario, Santa Fe, Argentina
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115
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Ma K, Yang LM, Chen HZ, Lu Y. Activation of muscarinic receptors inhibits glutamate-induced GSK-3β overactivation in PC12 cells. Acta Pharmacol Sin 2013; 34:886-92. [PMID: 23685950 DOI: 10.1038/aps.2013.42] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 03/20/2013] [Indexed: 01/05/2023] Open
Abstract
AIM To investigate the actions of the muscarinic agonist carbachol on glutamate-induced neurotoxicity in PC12 cells, and the underlying mechanisms. METHODS PC12 cells were treated with different concentrations of glutamate for 24 or 48 h. The cell viability was measured using MTT assay, and the expression and activation of GSK-3β were detected with Western blot. β-Catenin translocation was detected using immunofluorescence. Luciferase reporter assay and real-time PCR were used to analyze the transcriptional activity of β-catenin. RESULTS Glutamate (1, 3, and 10 mmol/L) induced PC12 cell death in a dose-dependent manner. Moreover, treatment of the cells with glutamate (1 mmol/L) caused significant overactivation of GSK-3β and prevented β-catenin translocation to the nucleus. Pretreatment with carbachol (0.01 μmol/L) blocked glutamate-induced cell death and GSK-3β overactivation, and markedly enhanced β-catenin transcriptional activity. CONCLUSION Activation of muscarinic receptors exerts neuroprotection in PC12 cells by attenuating glutamate-induced GSK-3β overactivation, suggesting potential benefits of muscarinic agonists for Alzheimer's disease.
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116
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Oliva CA, Vargas JY, Inestrosa NC. Wnt signaling: role in LTP, neural networks and memory. Ageing Res Rev 2013; 12:786-800. [PMID: 23665425 DOI: 10.1016/j.arr.2013.03.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 02/15/2013] [Accepted: 03/05/2013] [Indexed: 01/07/2023]
Abstract
Wnt components are key regulators of a variety of developmental processes, including embryonic patterning, cell specification, and cell polarity. The Wnt signaling pathway participates in the development of the central nervous system and growing evidence indicates that Wnts also regulates the function of the adult nervous system. In fact, most of the key components including Wnts and Frizzled receptors are expressed in the adult brain. Wnt ligands have been implicated in the regulation of synaptic assembly as well as in neurotransmission and synaptic plasticity. Deregulation of Wnt signaling has been associated with several pathologies, and more recently has been related to neurodegenerative diseases and to mental and mood disorders. In this review, we focus our attention on the Wnt signaling cascade in postnatal life and we review in detail the presence of Wnt signaling components in pre- and postsynaptic regions. Due to the important role of Wnt proteins in wiring neural circuits, we discuss recent findings about the role of Wnt pathways both in basal spontaneous activities as well as in activity-dependent processes that underlie synaptic plasticity. Finally, we review the role of Wnt in vivo and we finish with the most recent data in literature that involves the effect of components of the Wnt signaling pathway in neurological and mental disorders, including a special emphasis on in vivo studies that relate behavioral abnormalities to deficiencies in Wnt signaling, as well as the data that support a neuroprotective role of Wnt proteins in relation to the pathogenesis of Alzheimer's disease.
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Marchetti B, L'Episcopo F, Morale MC, Tirolo C, Testa N, Caniglia S, Serapide MF, Pluchino S. Uncovering novel actors in astrocyte-neuron crosstalk in Parkinson's disease: the Wnt/β-catenin signaling cascade as the common final pathway for neuroprotection and self-repair. Eur J Neurosci 2013; 37:1550-63. [PMID: 23461676 PMCID: PMC3660182 DOI: 10.1111/ejn.12166] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 01/21/2013] [Accepted: 01/25/2013] [Indexed: 12/31/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder characterized by progressive loss of dopaminergic (DAergic) neuronal cell bodies in the substantia nigra pars compacta and gliosis. The cause and mechanisms underlying the demise of nigrostriatal DAergic neurons are ill-defined, but interactions between genes and environmental factors are recognized to play a critical role in modulating the vulnerability to PD. Current evidence points to reactive glia as a pivotal factor in PD pathophysiology, playing both protective and destructive roles. Here, the contribution of reactive astrocytes and their ability to modulate DAergic neurodegeneration, neuroprotection and neurorepair in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) rodent model of PD will be discussed in the light of novel emerging evidence implicating wingless-type mouse mammary tumor virus integration site (Wnt)/β-catenin signaling as a strong candidate in MPTP-induced nigrostriatal DAergic plasticity. In this work, we highlight an intrinsic Wnt1/frizzled-1/β-catenin tone that critically contributes to the survival and protection of adult midbrain DAergic neurons, with potential implications for drug design or drug action in PD. The dynamic interplay between astrocyte-derived factors and neurogenic signals in MPTP-induced nigrostriatal DAergic neurotoxicity and repair will be summarized, together with recent findings showing a critical role of glia-neural stem/progenitor cell (NPC) interactions aimed at overcoming neurodegeneration and inducing neurorestoration. Understanding the intrinsic plasticity of nigrostriatal DAergic neurons and deciphering the signals facilitating the crosstalk between astrocytes, microglia, DAergic neurons and NPCs may have major implications for the role of stem cell technology in PD, and for identifying potential therapeutic targets to induce endogenous neurorepair.
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Affiliation(s)
- Bianca Marchetti
- Department of Clinical and Molecular Biomedicine, Pharmacology Section, Medical School, University of Catania, Catania, Italy.
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Genade T, Lang DM. Resveratrol extends lifespan and preserves glia but not neurons of the Nothobranchius guentheri optic tectum. Exp Gerontol 2012; 48:202-12. [PMID: 23220248 DOI: 10.1016/j.exger.2012.11.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/07/2012] [Accepted: 11/26/2012] [Indexed: 12/14/2022]
Abstract
Resveratrol is reported as having neuroprotective properties, however, much of this reputation has come from research using disease and injury models of neurodegeneration and not neurodegenerative-ageing. The results published here pertain to the affect resveratrol has on neurodegenerative-ageing. Resveratrol had previously been used to extend the lifespan of Nothobranchius furzeri wherein it preserved cognition and reduced ageing-associated neurodegeneration. No cell-type specific antibodies were then identified which could be used to investigate the nature of the neurodegeneration or resveratrols effect on CNS cells. Using wholemounts stained with SMI31 anti-phospho-neurolament, GA-5 and DAKO Z0334 anti-GFAP antibodies, E587 antiserum against NCAMs and anti-tenascin-R antibodies we determined what cellular changes occurred with age in the optic tectum of Nothobranchius guentheri. We show that resveratrol-treatment extended the lifespan of N. guentheri but did not preserve neuron density of the optic tectum stratum griseum superciale even though it did reduce the proportion of degenerate (SMI31 antigen accumulating) neurons in the optic tectum. Resveratrol-treatment did prevent the ageing-dependent loss of radial glia lining the optic tectum of N. guentheri. The ageing-related loss of NCAM expression and tenascin-R expressing perineuronal nets was also prevented by resveratrol-treatment. Glial and perineuronal density as well as NCAM expression appear to correlate well with age. These results suggest that the anti-ageing properties of resveratrol in vertebrates may be unrelated to the protection of neurons.
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Affiliation(s)
- T Genade
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Private Bag X3, Observatory, 7935, South Africa.
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Inestrosa NC, Montecinos-Oliva C, Fuenzalida M. Wnt signaling: role in Alzheimer disease and schizophrenia. J Neuroimmune Pharmacol 2012; 7:788-807. [PMID: 23160851 DOI: 10.1007/s11481-012-9417-5] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 10/30/2012] [Indexed: 12/16/2022]
Abstract
Wnt signaling function starts during the development of the nervous system and is crucial for synaptic plasticity in the adult brain. Clearly Wnt effects in synaptic and plastic processes are relevant, however the implication of this pathway in the prevention of neurodegenerative diseases that produce synaptic impairment, is even more interesting. Several years ago our laboratory found a relationship between the loss of Wnt signaling and the neurotoxicity of the amyloid-β-peptide (Aβ), one of the main players in Alzheimer's disease (AD). Moreover, the activation of the Wnt signaling cascade prevents Aβ-dependent cytotoxic effects. In fact, disrupted Wnt signaling may be a direct link between Aβ-toxicity and tau hyperphosphorylation, ultimately leading to impaired synaptic plasticity and/or neuronal degeneration, indicating that a single pathway can account for both neuro-pathological lesions and altered synaptic function. These observations, suggest that a sustained loss of Wnt signaling function may be a key relevant factor in the pathology of AD. On the other hand, Schizophrenia remains one of the most debilitating and intractable illness in psychiatry. Since Wnt signaling is important in organizing the developing brain, it is reasonable to propose that defects in Wnt signaling could contribute to Schizophrenia, particularly since the neuro-developmental hypothesis of the disease implies subtle dys-regulation of brain development, including some core components of the Wnt signaling pathways such as GSK-3β or Disrupted in Schizophrenia-1 (DISC-1). This review focuses on the relationship between Wnt signaling and its potential relevance for the treatment of neurodegenerative and neuropsychiatric diseases including AD and Schizophrenia.
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Affiliation(s)
- Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile.
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Zhou F, Chen S, Xiong J, Li Y, Qu L. Luteolin reduces zinc-induced tau phosphorylation at Ser262/356 in an ROS-dependent manner in SH-SY5Y cells. Biol Trace Elem Res 2012; 149:273-9. [PMID: 22528780 DOI: 10.1007/s12011-012-9411-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 03/28/2012] [Indexed: 01/08/2023]
Abstract
In brain, excess zinc alters the metabolism of amyloid precursor protein, leading to β-amyloid protein deposition, one of the hallmarks of Alzheimer's disease (AD) pathology. Recently, it has been reported that zinc accelerates in vitro tau fibrillization, another hallmark of AD. In the current study, we examined the effect of high-concentration zinc on tau phosphorylation in human neuroblastoma SH-SY5Y cells. We found that incubation of cells with zinc resulted in abnormal tau phosphorylation at Ser262/356. Moreover, the current study has investigated whether luteolin (Lu), a bioflavonoid, could decrease zinc-induced tau hyperphosphorylation and its underlying mechanisms. Using Western blot and protein phosphatase activity assay, activities of tau kinases and phosphatase were investigated. Our data suggest (1) that zinc induces tau hyperphosphorylation at Ser262/356 epitope and (2) that Lu efficiently attenuates zinc-induced tau hyperphosphorylation through not only its antioxidant action but also its regulation of the phosphorylation/dephosphorylation system.
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Affiliation(s)
- Futao Zhou
- School of Physical Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, China.
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Peng F, Yao H, Akturk HK, Buch S. Platelet-derived growth factor CC-mediated neuroprotection against HIV Tat involves TRPC-mediated inactivation of GSK 3beta. PLoS One 2012; 7:e47572. [PMID: 23077641 PMCID: PMC3471979 DOI: 10.1371/journal.pone.0047572] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 09/17/2012] [Indexed: 12/14/2022] Open
Abstract
Platelet-derived growth factor-CC (PDGF-CC) is the third member of the PDGF family, and has been implicated both in embryogenesis and development of the CNS. The biological function of this isoform however, remains largely unexplored in the context of HIV-associated dementia (HAD). In the present study, we demonstrate that exposure of human neuroblastoma cells SH-SY5Y to HIV transactivator protein Tat resulted in decreased intrinsic expression of PDGF-CC as evidenced by RT-PCR and western blot assays. Reciprocally, pretreatment of SH-SY5Y cells with PDGF-CC abrogated Tat-mediated neurotoxicity by mitigating apoptosis and neurite & MAP-2 loss. Using pharmacological and loss of function approaches we identified the role of phosphatidylinositol 3-kinase (PI3K)/Akt signaling in PDGF-CC-mediated neuroprotection. We report herein a novel role about the involvement of transient receptor potential canonical (TRPC) channel 1 in modulation of calcium transients in PDGF-CC-mediated neuroprotection. Furthermore we also demonstrated PDGF-CC-mediated inactivation of the downstream mediator - glycogen synthase kinase 3β (GSK3β) evidenced by its phosphorylation at Ser-9. This was further validated by gain and loss of function studies using cells transfected with either the wild type or mutant GSK3β constructs. Intriguingly, pretreatment of cells with either the PI3K inhibitor or TRPC blocker resulted in failure of PDGF-CC to inactivate GSK3β, thereby suggesting the intersection of PI3K and TRPC signaling at GSK3β. Taken together our findings lead to the suggestion that PDGF-CC could be developed as a therapeutic target to reverse Tat-mediated neurotoxicity with implications for HAD.
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Affiliation(s)
- Fuwang Peng
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Honghong Yao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Halis Kaan Akturk
- Department of Medicine, Creighton Medical Center, Omaha, Nebraska, United States of America
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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Molecular Mechanisms Underlie Alzheimer-like Tau Hyperphosphorylation and Neurodegeneration*. PROG BIOCHEM BIOPHYS 2012. [DOI: 10.3724/sp.j.1206.2012.00333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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124
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Liu XA, Song J, Jiang Q, Wang Q, Tian Q, Wang JZ. Expression of the hyperphosphorylated tau attenuates ER stress-induced apoptosis with upregulation of unfolded protein response. Apoptosis 2012; 17:1039-49. [DOI: 10.1007/s10495-012-0744-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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125
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Chen Y, Guan Y, Liu H, Wu X, Yu L, Wang S, Zhao C, Du H, Wang X. Activation of the Wnt/β-catenin signaling pathway is associated with glial proliferation in the adult spinal cord of ALS transgenic mice. Biochem Biophys Res Commun 2012; 420:397-403. [DOI: 10.1016/j.bbrc.2012.03.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 03/02/2012] [Indexed: 11/28/2022]
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126
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Liu GP, Wei W, Zhou X, Zhang Y, Shi HH, Yin J, Yao XQ, Peng CX, Hu J, Wang Q, Li HL, Wang JZ. I2PP2A regulates p53 and Akt correlatively and leads the neurons to abort apoptosis. Neurobiol Aging 2012; 33:254-64. [DOI: 10.1016/j.neurobiolaging.2010.01.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 01/18/2010] [Accepted: 01/19/2010] [Indexed: 01/07/2023]
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127
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Jiang X, Tian Q, Wang Y, Zhou XW, Xie JZ, Wang JZ, Zhu LQ. Acetyl-L-Carnitine ameliorates spatial memory deficits induced by inhibition of phosphoinositol-3 kinase and protein kinase C. J Neurochem 2011; 118:864-78. [DOI: 10.1111/j.1471-4159.2011.07355.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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128
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L'Episcopo F, Serapide MF, Tirolo C, Testa N, Caniglia S, Morale MC, Pluchino S, Marchetti B. A Wnt1 regulated Frizzled-1/β-Catenin signaling pathway as a candidate regulatory circuit controlling mesencephalic dopaminergic neuron-astrocyte crosstalk: Therapeutical relevance for neuron survival and neuroprotection. Mol Neurodegener 2011; 6:49. [PMID: 21752258 PMCID: PMC3162575 DOI: 10.1186/1750-1326-6-49] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 07/13/2011] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Dopamine-synthesizing (dopaminergic, DA) neurons in the ventral midbrain (VM) constitute a pivotal neuronal population controlling motor behaviors, cognitive and affective brain functions, which generation critically relies on the activation of Wingless-type MMTV integration site (Wnt)/β-catenin pathway in their progenitors. In Parkinson's disease, DA cell bodies within the substantia nigra pars compacta (SNpc) progressively degenerate, with causes and mechanisms poorly understood. Emerging evidence suggests that Wnt signaling via Frizzled (Fzd) receptors may play a role in different degenerative states, but little is known about Wnt signaling in the adult midbrain. Using in vitro and in vivo model systems of DA degeneration, along with functional studies in both intact and SN lesioned mice, we herein highlight an intrinsic Wnt1/Fzd-1/β-catenin tone critically contributing to the survival and protection of adult midbrain DA neurons. RESULTS In vitro experiments identifie Fzd-1 receptor expression at a mRNA and protein levels in dopamine transporter (DAT) expressing neurons, and demonstrate the ability of exogenous Wnt1 to exert robust neuroprotective effects against Caspase-3 activation, the loss of tyrosine hydroxylase-positive (TH+) neurons and [3H] dopamine uptake induced by different DA-specific insults, including serum and growth factor deprivation, 6-hydroxydopamine and MPTP/MPP+. Co-culture of DA neurons with midbrain astrocytes phenocopies Wnt1 neuroprotective effects, whereas RNA interference-mediated knockdown of Wnt1 in midbrain astrocytes markedly reduces astrocyte-induced TH+ neuroprotection. Likewise, silencing β-catenin mRNA or knocking down Fzd-1 receptor expression in mesencephalic neurons counteract astrocyte-induced TH+ neuroprotection. In vivo experiments document Fzd-1 co-localization with TH+ neurons within the intact SNpc and blockade of Fzd/β-catenin signaling by unilateral infusion of a Fzd/β-catenin antagonist within the SN induces reactive astrocytosis and acutely inhibits TH+ neuron survival in ipsilateral SNpc, an effect efficiently prevented by pharmacological activation of β-catenin signaling within the SNpc. CONCLUSION These results defining a novel Wnt1/Fzd-1/β-catenin astrocyte-DA autoprotective loop provide a new mechanistic inside into the regulation of pro-survival processes, with potentially relevant consequences for drug design or drug action in Parkinson's disease.
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Affiliation(s)
- Francesca L'Episcopo
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section; Via Conte Ruggero 73, 94018 Troina (EN), Italy
| | - Maria F Serapide
- Department of Biomedical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Cataldo Tirolo
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section; Via Conte Ruggero 73, 94018 Troina (EN), Italy
| | - Nunzio Testa
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section; Via Conte Ruggero 73, 94018 Troina (EN), Italy
| | - Salvatore Caniglia
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section; Via Conte Ruggero 73, 94018 Troina (EN), Italy
| | - Maria C Morale
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section; Via Conte Ruggero 73, 94018 Troina (EN), Italy
| | - Stefano Pluchino
- Cambridge Centre for Brain Repair Department of Clinical Neurosciences ED Adrian Building Forvie Site Robinson Way Cambridge CB2 0PY, USA
| | - Bianca Marchetti
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section; Via Conte Ruggero 73, 94018 Troina (EN), Italy
- Department of Clinical and Molecular Biomedicine, Pharmacology Section, Faculty of Medicine, and Faculty of Pharmacy, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
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129
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Mines MA, Beurel E, Jope RS. Regulation of cell survival mechanisms in Alzheimer's disease by glycogen synthase kinase-3. Int J Alzheimers Dis 2011; 2011:861072. [PMID: 21629713 PMCID: PMC3100684 DOI: 10.4061/2011/861072] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 03/09/2011] [Indexed: 11/27/2022] Open
Abstract
A pivotal role has emerged for glycogen synthase kinase-3 (GSK3) as an important contributor to Alzheimer's disease pathology. Evidence for the involvement of GSK3 in Alzheimer's disease pathology and neuronal loss comes from studies of GSK3 overexpression, GSK3 localization studies, multiple relationships between GSK3 and amyloid β-peptide (Aβ), interactions between GSK3 and the microtubule-associated tau protein, and GSK3-mediated apoptotic cell death. Apoptotic signaling proceeds by either an intrinsic pathway or an extrinsic pathway. GSK3 is well established to promote intrinsic apoptotic signaling induced by many insults, several of which may contribute to neuronal loss in Alzheimer's disease. Particularly important is evidence that GSK3 promotes intrinsic apoptotic signaling induced by Aβ. GSK3 appears to promote intrinsic apoptotic signaling by modulating proteins in the apoptosis signaling pathway and by modulating transcription factors that regulate the expression of proteins involved in apoptosis. Thus, GSK3 appears to contribute to several neuropathological mechanisms in Alzheimer's disease, including apoptosis-mediated neuronal loss.
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Affiliation(s)
- Marjelo A Mines
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Sparks Center 1057, 1720 Seventh Avenue South, Birmingham, AL 35294-0017, USA
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130
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Mitochondrial dysfunction - the beginning of the end in Alzheimer's disease? Separate and synergistic modes of tau and amyloid-β toxicity. ALZHEIMERS RESEARCH & THERAPY 2011; 3:15. [PMID: 21545753 PMCID: PMC3226305 DOI: 10.1186/alzrt74] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The pathology of Alzheimer's disease (AD) is characterized by amyloid plaques (aggregates of amyloid-β (Aβ)) and neurofibrillary tangles (aggregates of tau) and is accompanied by mitochondrial dysfunction, but the mechanisms underlying this dysfunction are poorly understood. In this review, we discuss the critical role of mitochondria and the close inter-relationship of this organelle with the two main pathological features in the pathogenic process underlying AD. Moreover, we summarize evidence from AD post-mortem brain as well as cellular and animal AD models showing that Aβ and tau protein trigger mitochondrial dysfunction through a number of pathways, such as impairment of oxidative phosphorylation, elevation of reactive oxygen species production, alteration of mitochondrial dynamics, and interaction with mitochondrial proteins. A vicious cycle as well as several vicious circles within the cycle, each accelerating the other, can be drawn, emphasizing the synergistic deterioration of mitochondria by tau and Aβ.
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131
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Koistinaho J, Malm T, Goldsteins G. Glycogen synthase kinase-3β: a mediator of inflammation in Alzheimer's disease? Int J Alzheimers Dis 2011; 2011:129753. [PMID: 21629736 PMCID: PMC3100542 DOI: 10.4061/2011/129753] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 03/04/2011] [Indexed: 02/03/2023] Open
Abstract
Proliferation and activation of microglial cells is a neuropathological characteristic of brain injury and neurodegeneration, including Alzheimer's disease. Microglia act as the first and main form of immune defense in the nervous system. While the primary function of microglia is to survey and maintain the cellular environment optimal for neurons in the brain parenchyma by actively scavenging the brain for damaged brain cells and foreign proteins or particles, sustained activation of microglia may result in high production of proinflammatory mediators that disturb normal brain functions and even cause neuronal injury. Glycogen synthase kinase-3β has been recently identified as a major regulator of immune system and mediates inflammatory responses in microglia. Glycogen synthase kinase-3β has been extensively investigated in connection to tau and amyloid β toxicity, whereas reports on the role of this enzyme in neuroinflammation in Alzheimer's disease are negligible. Here we review and discuss the role of glycogen synthase-3β in immune cells in the context of Alzheimer's disease pathology.
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Affiliation(s)
- Jari Koistinaho
- Department of Neurobiology, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
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132
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Obulesu M, Venu R, Somashekhar R. Tau mediated neurodegeneration: an insight into Alzheimer's disease pathology. Neurochem Res 2011; 36:1329-35. [PMID: 21509508 DOI: 10.1007/s11064-011-0475-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2011] [Indexed: 12/13/2022]
Abstract
Extracellular accumulations of Aβ, hyperphosphorylation of tau and intracellular neurofibrillary tangle formation have been the hallmarks of Alzheimer's Disease (AD). Although tau and its phosphorylation play a pivotal role in the normal physiology yet its hyperphosphorylation has been a pathological manifestation in neurodegenerative disorders like AD. In this review physiology of tau, its phosphorylation, hyperphosphorylation with the intervention of various kinases, aggregation and formation of paired helical filaments has been discussed. A brief account of various animal models employed to study the pathological manifestation of tau in AD and therapeutic strategies streamlined to counter the tau induced pathology has been given. The reasons for the failure to have suitable animal model to study AD pathology and recent success in achieving this has been included. The role of caspase cascade in tau cleavage has been emphasized. The summary of current studies on tau and the need for future studies has been accentuated.
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Affiliation(s)
- M Obulesu
- Department of Biotechnology, Rayalaseema University, Kurnool, India.
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133
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Hong XP, Peng CX, Wei W, Tian Q, Liu YH, Yao XQ, Zhang Y, Cao FY, Wang Q, Wang JZ. Essential role of tau phosphorylation in adult hippocampal neurogenesis. Hippocampus 2011; 20:1339-49. [PMID: 19816983 DOI: 10.1002/hipo.20712] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
An increased hippocampal neurogenesis has been observed in Alzheimer disease (AD), the most common neurodegenerative disorder characterized with accumulation of β-amyloid (Aβ) and hyperphosphorylated tau (p-tau). Studies in transgenic mouse models suggest that the amyloidosis suppresses adult neurogenesis. Although emerging evidence links tau to neurodevelopment, the direct data regarding tau phosphorylation in adult neurogenesis is missing. Here, we found that the immature neurons, identified by doublecortin (DCX) and neurogenic differentiation factor (neuroD), were only immunoreactive to p-tau but not to the non-p-tau in adult rat brain and human patients with AD, and the p-tau was coexpressed temporally and spatially with DCX and neuroD in the hippocampal dentate gyrus (DG) of the rat brains during postnatal development. A correlative increase of immature neuron markers and tau phosphorylation was induced in rat hippocampal DG by upregulating glycogen synthase kinase-3 (GSK-3), a crucial tau kinase, and the increased neurogenesis was due to an enhanced proliferation but not survival or differentiation of the newborn neurons. The hippocampal neurogenesis was severely impaired in tau knockout mice and activation of GSK-3 in these mice did not rescue the deficits. These results reveal an essential role of tau phosphorylation in adult hippocampal neurogenesis. It suggests that spatial/temporal manipulation of tau phosphorylation may be compensatory for the neuron loss in neurological disorders, including AD.
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Affiliation(s)
- Xiao-Ping Hong
- Department of Pathophysiology, Key Laboratory of Neurological Diseases of Education Committee of China, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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L’Episcopo F, Tirolo C, Testa N, Caniglia S, Morale M, Cossetti C, D’Adamo P, Zardini E, Andreoni L, Ihekwaba A, Serra P, Franciotta D, Martino G, Pluchino S, Marchetti B. Reactive astrocytes and Wnt/β-catenin signaling link nigrostriatal injury to repair in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease. Neurobiol Dis 2011; 41:508-27. [PMID: 21056667 PMCID: PMC3558878 DOI: 10.1016/j.nbd.2010.10.023] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 10/15/2010] [Accepted: 10/27/2010] [Indexed: 02/07/2023] Open
Abstract
Emerging evidence points to reactive glia as a pivotal factor in Parkinson's disease (PD) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model of basal ganglia injury, but whether astrocytes and microglia activation may exacerbate dopaminergic (DAergic) neuron demise and/or contribute to DAergic repair is presently the subject of much debate. Here, we have correlated the loss and recovery of the nigrostriatal DAergic functionality upon acute MPTP exposure with extensive gene expression analysis at the level of the ventral midbrain (VM) and striata (Str) and found a major upregulation of pro-inflammatory chemokines and wingless-type MMTV integration site1 (Wnt1), a key transcript involved in midbrain DAergic neurodevelopment. Wnt signaling components (including Frizzled-1 [Fzd-1] and β-catenin) were dynamically regulated during MPTP-induced DAergic degeneration and reactive glial activation. Activated astrocytes of the ventral midbrain were identified as candidate source of Wnt1 by in situ hybridization and real-time PCR in vitro. Blocking Wnt/Fzd signaling with Dickkopf-1 (Dkk1) counteracted astrocyte-induced neuroprotection against MPP(+) toxicity in primary mesencephalic astrocyte-neuron cultures, in vitro. Moreover, astroglial-derived factors, including Wnt1, promoted neurogenesis and DAergic neurogenesis from adult midbrain stem/neuroprogenitor cells, in vitro. Conversely, lack of Wnt1 transcription in response to MPTP in middle-aged mice and failure of DAergic neurons to recover were reversed by pharmacological activation of Wnt/β-catenin signaling, in vivo, thus suggesting MPTP-reactive astrocytes in situ and Wnt1 as candidate components of neuroprotective/neurorescue pathways in MPTP-induced nigrostriatal DAergic plasticity.
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Affiliation(s)
- F. L’Episcopo
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section, Via Conte Ruggero 73, 94018 Troina (EN) Italy
| | - C. Tirolo
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section, Via Conte Ruggero 73, 94018 Troina (EN) Italy
| | - N. Testa
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section, Via Conte Ruggero 73, 94018 Troina (EN) Italy
| | - S. Caniglia
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section, Via Conte Ruggero 73, 94018 Troina (EN) Italy
| | - M.C. Morale
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section, Via Conte Ruggero 73, 94018 Troina (EN) Italy
| | - C. Cossetti
- Cambridge Centre for Brain Repair Department of Clinical Neurosciences ED Adrian Building Forvie Site Robinson Way Cambridge CB2 0PY, UK
| | - P. D’Adamo
- Molecular Genetics of Mental Retardation Unit, San Raffaele Institute, Via Olgettina, 58 I-20132 Milan, Italy
| | - E. Zardini
- Neuroimmunology Unit, National Neurological Instititute C. Mondino, Via Mondino 2, 27100 Pavia, Italy
| | - L. Andreoni
- Neuroimmunology Unit, National Neurological Instititute C. Mondino, Via Mondino 2, 27100 Pavia, Italy
| | - A.E.C. Ihekwaba
- Cambridge Centre for Brain Repair Department of Clinical Neurosciences ED Adrian Building Forvie Site Robinson Way Cambridge CB2 0PY, UK
| | - P.A. Serra
- Department of Pharmacology, University of Sassari, Medical School, Viale S. Pietro 43, 07100 Sassari, Italy
| | - D. Franciotta
- Department of Pharmacology, University of Sassari, Medical School, Viale S. Pietro 43, 07100 Sassari, Italy
| | - G. Martino
- San Raffaele Institute, Neuroimmunology Unit, DIBIT2 and Institute of Experimental Neurology (INSPE), Via Olgettina, 58 I-20132 Milan, Italy
| | - S. Pluchino
- Cambridge Centre for Brain Repair Department of Clinical Neurosciences ED Adrian Building Forvie Site Robinson Way Cambridge CB2 0PY, UK
| | - B. Marchetti
- OASI Institute for Research and Care on Mental Retardation and Brain Aging, Neuropharmacology Section, Via Conte Ruggero 73, 94018 Troina (EN) Italy
- Department of Clinical and Molecular Biomedicine, Pharmacology Section, University of Catania, Viale A. Doria, 95125 Catania, Italy
- Faculty of Pharmacy, University of Catania, Viale A. Doria, 95125 Catania, Italy
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135
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Zhang L, Yang X, Yang S, Zhang J. The Wnt /β-catenin signaling pathway in the adult neurogenesis. Eur J Neurosci 2010; 33:1-8. [PMID: 21073552 DOI: 10.1111/j.1460-9568.2010.7483.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The Wnt/β-catenin signaling pathway plays an important role in neural development, β-catenin is a central component of the Wnt/β-catenin signaling pathway, which not only performs the function of transmitting information in the cytoplasm, but also translocates to the nucleus-activating target gene transcription. The target genes in neural tissues have not been fully revealed, but the effects of the Wnt/β-catenin signaling pathway in adult neurogenesis have been demonstrated by ongoing research, which are significative to the basic research and treatment of neuronal degeneration diseases. Here, we review key findings to show the characteristics of β-catenin and its pivotal nature in the Wnt/β-catenin signaling pathway in a number of molecular studies. We also review current literature on the role of β-catenin in adult neurogenesis, which consists of an active process encompassing the proliferation, migration, differentiation and final synaptogenesis.
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Affiliation(s)
- Lin Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin Key Laboratory of Injuries,Variations and Regeneration of Nervous System, Tianjin, China
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136
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Park SA, Park HW, Kim NH, Kim YH, Kwak MJ, Shin JS, Kim CW. Effects of Tau on the activity of triose phosphate isomerase (TPI) in brain cells. Neurochem Int 2010; 56:886-92. [DOI: 10.1016/j.neuint.2010.03.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 03/18/2010] [Accepted: 03/18/2010] [Indexed: 11/30/2022]
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137
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Medeiros R, Baglietto-Vargas D, LaFerla FM. The role of tau in Alzheimer's disease and related disorders. CNS Neurosci Ther 2010; 17:514-24. [PMID: 20553310 DOI: 10.1111/j.1755-5949.2010.00177.x] [Citation(s) in RCA: 196] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Tau, the microtubule-associated protein, forms insoluble filaments that accumulate as neurofibrillary tangles in Alzheimer's disease (AD) and related tauopathies. Under physiological conditions, tau regulates the assembly and maintenance of the structural stability of microtubules. In the diseased brain, however, tau becomes abnormally hyperphosphorylated, which ultimately causes the microtubules to disassemble, and the free tau molecules aggregate into paired helical filaments. A large body of evidence suggests that tau hyperphosphorylation results from perturbation of cellular signaling, mainly through imbalance in the activities of different protein kinases and phosphatases. In AD, it appears that ß-amyloid peptide (Aß) plays a pivotal role in triggering this imbalance. In this review, we summarize our current understanding of the role of tau in AD and other tauopathies, and highlight key issues that need to be addressed to improve the success of developing novel therapies.
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Affiliation(s)
- Rodrigo Medeiros
- Department of Neurobiology and Behavior and Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
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138
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Bonda DJ, Wang X, Perry G, Smith MA, Zhu X. Mitochondrial dynamics in Alzheimer's disease: opportunities for future treatment strategies. Drugs Aging 2010; 27:181-92. [PMID: 20210366 DOI: 10.2165/11532140-000000000-00000] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The complexities that underlie the cognitive impairment and neurodegeneration characteristic of Alzheimer's disease (AD) have yet to be completely understood, although many factors in disease pathogenesis have been identified. Particularly important in disease development seem to be mitochondrial disturbances. As pivotal role players in cellular metabolism, mitochondria are pertinent to cell survival and thus any deviation from their operation is certainly fatal. In this review, we describe how the dynamic balance of mitochondrial fission and fusion in particular is a necessary aspect of cell proliferation and that, as the cell ages, such balance is inevitably compromised to yield a destructive environment in which the cell cannot exist. Evidence for such disturbance is abundant in AD. Specifically, the dynamic balance of fission and fusion in AD is greatly shifted toward fission, and, as a result, affected neurons contain abnormal mitochondria that are unable to meet the metabolic demands of the cell. Moreover, mitochondrial distribution in AD cells is perinuclear, with few metabolic organelles in the distal processes, where they are normally distributed in healthy cells and are needed for exocytosis, ion channel pumps, synaptic function and other activities. AD neurons are thus characterized by increases in reactive oxidative species and decreases in metabolic capability, and, notably, these changes are evident very early in AD progression. We therefore believe that oxidative stress and altered mitochondrial dynamics contribute to the precipitation of AD pathology and thus cognitive decline. These implications provide a window for therapeutic intervention (i.e. mitochondrial protection) that has the potential to significantly deter AD progression if adequately developed. Current treatment strategies under investigation are described in this review.
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Affiliation(s)
- David J Bonda
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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139
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Norrin mediates neuroprotective effects on retinal ganglion cells via activation of the Wnt/beta-catenin signaling pathway and the induction of neuroprotective growth factors in Muller cells. J Neurosci 2010; 30:5998-6010. [PMID: 20427659 DOI: 10.1523/jneurosci.0730-10.2010] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Norrin is a secreted protein that binds to frizzled 4 and controls development of capillaries in retina and inner ear. We provide evidence that Norrin has distinct neuroprotective properties that are independent from its effects on vascular development. The function of Norrin was investigated in a mouse model of excitotoxic retinal ganglion cell (RGC) damage after intravitreal injection of NMDA, and in cultured Müller glia or immortalized RGC-5 cells. Intravitreal injection of Norrin significantly increased the number of surviving RGC axons in the optic nerve and decreased apoptotic death of retinal neurons following NMDA-mediated damage. This effect could be blocked by adding dickkopf (DKK)-1, an inhibitor of the Wnt/beta-catenin signaling pathway. Treatment of eyes with combined Norrin/NMDA activated Wnt/beta-catenin signaling and increased the retinal expression of leukemia inhibitory factor and endothelin-2, as well as that of neurotrophic growth factors such as fibroblast growth factor-2, brain-derived neurotrophic factor, lens epithelium-derived growth factor, and ciliary neurotrophic factor. A similar activation of Wnt/beta-catenin signaling and an increased expression of neurotrophic factors was observed in cultured Müller cells after treatment with Norrin, effects that again could be blocked by adding DKK-1. In addition, conditioned cell culture medium of Norrin-treated Müller cells increased survival of differentiated RGC-5 cells. We conclude that Norrin has pronounced neuroprotective properties on retinal neurons with the distinct potential to decrease the damaging effects of NMDA-induced RGC loss. The effects of Norrin involve activation of Wnt/beta-catenin signaling and subsequent induction of neurotrophic growth factors in Müller cells.
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140
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Zhou J. Recent progress in neurodegenerative disorder research in China. SCIENCE CHINA-LIFE SCIENCES 2010; 53:348-355. [DOI: 10.1007/s11427-010-0061-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Accepted: 01/19/2010] [Indexed: 11/25/2022]
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141
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de Barreda EG, Pérez M, Ramos PG, de Cristobal J, Martín-Maestro P, Morán A, Dawson HN, Vitek MP, Lucas JJ, Hernández F, Avila J. Tau-knockout mice show reduced GSK3-induced hippocampal degeneration and learning deficits. Neurobiol Dis 2010; 37:622-9. [DOI: 10.1016/j.nbd.2009.11.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 10/23/2009] [Accepted: 11/23/2009] [Indexed: 01/13/2023] Open
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142
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Jiang X, Yu Y, Yang HW, Agar NYR, Frado L, Johnson MD. The imprinted gene PEG3 inhibits Wnt signaling and regulates glioma growth. J Biol Chem 2010; 285:8472-80. [PMID: 20064927 PMCID: PMC2832996 DOI: 10.1074/jbc.m109.069450] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The imprinted gene PEG3 confers parenting and sexual behaviors, alters growth and development, and regulates apoptosis. However, a molecular mechanism that can account for the diverse functions of Peg3/Pw1 is not known. To elucidate Peg3-regulated pathways, we performed a functional screen in zebrafish. Enforced overexpression of PEG3 mRNA during zebrafish embryogenesis decreased β-catenin protein expression and inhibited Wnt-dependent tail development. Peg3/Pw1 also inhibited Wnt signaling in human cells by binding to β-catenin and promoting its degradation via a p53/Siah1-dependent, GSK3β-independent proteasomal pathway. The inhibition of the Wnt pathway by Peg3/Pw1 suggested a role in tumor suppression. Hypermethylation of the PEG3 promoter in primary human gliomas led to a loss of imprinting and decreased PEG3 mRNA expression that correlated with tumor grade. The decrease in Peg3/Pw1 protein expression increased β-catenin, promoted proliferation, and inhibited p53-dependent apoptosis in human CD133+ glioma stem cells. Thus, mammalian imprinting utilizes Peg3/Pw1 to co-opt the Wnt pathway, thereby regulating development and glioma growth.
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Affiliation(s)
- Xiuli Jiang
- Department of Neurosurgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA
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143
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Su B, Wang X, Lee HG, Tabaton M, Perry G, Smith MA, Zhu X. Chronic oxidative stress causes increased tau phosphorylation in M17 neuroblastoma cells. Neurosci Lett 2009; 468:267-71. [PMID: 19914335 DOI: 10.1016/j.neulet.2009.11.010] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 11/03/2009] [Accepted: 11/05/2009] [Indexed: 10/20/2022]
Abstract
Tau hyperphosphorylation appears to be a critical event leading to abnormal aggregation and disrupted function of tau in affected neurons in Alzheimer's disease (AD). As a prominent early event during AD pathogenesis, oxidative stress is believed to contribute to tau phosphorylation and the formation of neurofibrillary lesions. However, acute oxidative stress has disparate effects on tau phosphorylation. Given the chronic nature of AD, in this study, we aimed to determine the long-term effect of oxidative stress on tau phosphorylation. In this regard, we established a novel in vitro model of chronic oxidative stress through inhibition of glutathione (GSH) synthesis with BSO. We confirmed that these cells were under a chronic mild oxidative stress by looking at oxidative response, the induction of heme oxygenase 1 (HO-1) without neuronal death. Chronic oxidative stress increased levels of tau phosphorylated at PHF-1 epitope (serine 399/404) in a time-dependent manner. Our data further suggest that increased activity of JNK and p38 and decreased activity of PP2A are likely involved in chronic oxidative stress-induced tau phosphorylation. In conclusion we suggest that chronic oxidative stress contributes to increased tau phosphorylation in vitro and could play a critical role in neurofibrillary pathology in vivo.
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Affiliation(s)
- Bo Su
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
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144
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Hyperphosphorylation of microtubule-associated tau protein plays dual role in neurodegeneration and neuroprotection. PATHOPHYSIOLOGY 2009; 16:311-6. [DOI: 10.1016/j.pathophys.2009.02.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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145
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Behrens MI, Lendon C, Roe CM. A common biological mechanism in cancer and Alzheimer's disease? Curr Alzheimer Res 2009; 6:196-204. [PMID: 19519301 DOI: 10.2174/156720509788486608] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cancer and Alzheimer's disease (AD) are two common disorders for which the final pathophysiological mechanism is not yet clearly defined. In a prospective longitudinal study we have previously shown an inverse association between AD and cancer, such that the rate of developing cancer in general with time was significantly slower in participants with AD, while participants with a history of cancer had a slower rate of developing AD. In cancer, cell regulation mechanisms are disrupted with augmentation of cell survival and/or proliferation, whereas conversely, AD is associated with increased neuronal death, either caused by, or concomitant with, beta amyloid (Abeta) and tau deposition. The possibility that perturbations of mechanisms involved in cell survival/death regulation could be involved in both disorders is discussed. Genetic polymorphisms, DNA methylation or other mechanisms that induce changes in activity of molecules with key roles in determining the decision to "repair and live"- or "die" could be involved in the pathogenesis of the two disorders. As examples, the role of p53, Pin1 and the Wnt signaling pathway are discussed as potential candidates that, speculatively, may explain inverse associations between AD and cancer.
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Affiliation(s)
- M I Behrens
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile and Clínica Alemana Santiago, Chile.
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146
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Eggers AE. Why do Alzheimer’s disease and Parkinson’s disease target the same neurons? Med Hypotheses 2009; 72:698-700. [DOI: 10.1016/j.mehy.2008.12.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 12/08/2008] [Accepted: 12/10/2008] [Indexed: 12/21/2022]
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147
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Yanashima R, Kitagawa N, Matsubara Y, Weatheritt R, Oka K, Kikuchi S, Tomita M, Ishizaki S. [Not Available]. Front Neuroinform 2009; 3:13. [PMID: 19543432 PMCID: PMC2699032 DOI: 10.3389/neuro.11/013.2009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Accepted: 04/30/2009] [Indexed: 01/25/2023] Open
Abstract
The scale-free and small-world network models reflect the functional units of networks. However, when we investigated the network properties of a signaling pathway using these models, no significant differences were found between the original undirected graphs and the graphs in which inactive proteins were eliminated from the gene expression data. We analyzed signaling networks by focusing on those pathways that best reflected cellular function. Therefore, our analysis of pathways started from the ligands and progressed to transcription factors and cytoskeletal proteins. We employed the Python module to assess the target network. This involved comparing the original and restricted signaling cascades as a directed graph using microarray gene expression profiles of late onset Alzheimer's disease. The most commonly used method of shortest-path analysis neglects to consider the influences of alternative pathways that can affect the activation of transcription factors or cytoskeletal proteins. We therefore introduced included k-shortest paths and k-cycles in our network analysis using the Python modules, which allowed us to attain a reasonable computational time and identify k-shortest paths. This technique reflected results found in vivo and identified pathways not found when shortest path or degree analysis was applied. Our module enabled us to comprehensively analyse the characteristics of biomolecular networks and also enabled analysis of the effects of diseases considering the feedback loop and feedforward loop control structures as an alternative path.
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148
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Zhang M, Wang X, Jiang F, Wang W, Vincent I, Bu B. Mitotic epitopes are incorporated into age-dependent neurofibrillary tangles in Niemann-Pick disease type C. Brain Pathol 2009; 20:367-77. [PMID: 19476463 DOI: 10.1111/j.1750-3639.2009.00286.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The mechanism underlying neurofibrillary tangles (NFTs) in Alzheimer's disease (AD) and other neurodegenerative disorders remains elusive. Niemann-Pick disease type C (NPC) is a kind of genetic neurovisceral disorder in which the intracellular sequestration of cholesterol and other lipids in neurons, NFT formation and neuronal degeneration in brain are the neuropathology hallmarks. The age of onset and progression of the disease vary dramatically. We have analyzed the hippocampus from 17 NPC cases, aged from 7 months to 55 years, to depict the temporal characteristics of NFT formation. Unexpectedly, classic NFT was observed in about 4-year-old NPC brain, suggesting that NFT is not aging dependent, and that juvenile brain neurons satisfy the requirements for NFT formation. NFT in the hippocampus of NPC was significantly increased in number with the advance of age. More importantly, multiple mitotic phase markers, which are not usually found in normal mature neurons, were abundant in the affected neurons and incorporated into NFT. The unusual activation of cdc2/cyclin B kinase and downstream mitotic indices are closely associated with the age-dependent NFT formation, signifying the contribution of abortive cell cycle to neurodegeneration. The cdc2 inhibitors may be therapeutically used for early intervention of neurodegeneration and NFT formation in NPC.
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Affiliation(s)
- Min Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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149
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Boonen RA, van Tijn P, Zivkovic D. Wnt signaling in Alzheimer's disease: up or down, that is the question. Ageing Res Rev 2009; 8:71-82. [PMID: 19101658 DOI: 10.1016/j.arr.2008.11.003] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 11/26/2008] [Accepted: 11/26/2008] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder, neuropathologically characterized by amyloid-beta (Abeta) plaques and hyperphosphorylated tau accumulation. AD occurs sporadically (SAD), or is caused by hereditary missense mutations in the amyloid precursor protein (APP) or presenilin-1 and -2 (PSEN1 and PSEN2) genes, leading to early-onset familial AD (FAD). Accumulating evidence points towards a role for altered Wnt/beta-catenin-dependent signaling in the etiology of both forms of AD. Presenilins are involved in modulating beta-catenin stability; therefore FAD-linked PSEN-mediated effects can deregulate the Wnt pathway. Genetic variations in the low-density lipoprotein receptor-related protein 6 and apolipoprotein E in AD have been associated with reduced Wnt signaling. In addition, tau phosphorylation is mediated by glycogen synthase kinase-3 (GSK-3), a key antagonist of the Wnt pathway. In this review, we discuss Wnt/beta-catenin signaling in both SAD and FAD, and recapitulate which of its aberrant functions may be critical for (F)AD pathogenesis. We discuss the intriguing possibility that Abeta toxicity may downregulate the Wnt/beta-catenin pathway, thereby upregulating GSK-3 and consequent tau hyperphosphorylation, linking Abeta and tangle pathology. The currently available evidence implies that disruption of tightly regulated Wnt signaling may constitute a key pathological event in AD. In this context, drug targets aimed at rescuing Wnt signaling may prove to be a constructive therapeutic strategy for AD.
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150
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Su B, Wang X, Nunomura A, Moreira PI, Lee HG, Perry G, Smith MA, Zhu X. Oxidative stress signaling in Alzheimer's disease. Curr Alzheimer Res 2009; 5:525-32. [PMID: 19075578 DOI: 10.2174/156720508786898451] [Citation(s) in RCA: 201] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Multiple lines of evidence demonstrate that oxidative stress is an early event in Alzheimer's disease (AD), occurring prior to cytopathology, and therefore may play a key pathogenic role in AD. Oxidative stress not only temporally precedes the pathological lesions of the disease but also activates cell signaling pathways, which, in turn, contribute to lesion formation and, at the same time, provoke cellular responses such as compensatory upregulation of antioxidant enzymes found in vulnerable neurons in AD. In this review, we provide an overview of the evidence of oxidative stress and compensatory responses that occur in AD, particularly focused on potential sources of oxidative stress and the roles and mechanism of activation of stress-activated protein kinase pathways.
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Affiliation(s)
- B Su
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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