51
|
Kang Q, Xiang Y, Li D, Liang J, Zhang X, Zhou F, Qiao M, Nie Y, He Y, Cheng J, Dai Y, Li Y. MiR-124-3p attenuates hyperphosphorylation of Tau protein-induced apoptosis via caveolin-1-PI3K/Akt/GSK3β pathway in N2a/APP695swe cells. Oncotarget 2018; 8:24314-24326. [PMID: 28186985 PMCID: PMC5421849 DOI: 10.18632/oncotarget.15149] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/24/2017] [Indexed: 01/01/2023] Open
Abstract
Hyperphosphorylation of Tau forming neurofibrillary tangles has been considered as a crucial event in the pathogenesis of Alzheimer's disease (AD). MiR-124-3p belongs to microRNA (miRNA) family and was markedly decreased in AD, however, the functions of miR-124-3p in the pathogenesis of AD remain unknown. We observed that the expression of miR-124-3p was significantly decreased in N2a/APP695swe cells; and transfection of miR-124-3p mimics not only attenuated cell apoptosis and abnormal hyperphosphorylation of Tau protein without any changes of total Tau protein, but also increased expression levels of Caveolin-1, phosphoinositide 3-kinase (PI3K), phospho-Akt (Akt-Ser473)/Akt, phospho-glycogen synthase kinase-3 beta (GSK-3β-Ser9)/GSK-3β in N2a/APP695swe cells. We further found that miR-12-3p directly targeted Caveolin-1; miR-124-3p inhibited abnormal hyperphosphorylation of Tau by regulating Caveolin-1-PI3K/Akt/GSK3β pathway in AD. This study reveals that miR-124-3p may play a neuroprotective role in AD, which may provide new ideas and therapeutic targets for AD.
Collapse
Affiliation(s)
- Qingmei Kang
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Yue Xiang
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Dan Li
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Jie Liang
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Xiong Zhang
- Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Fanlin Zhou
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Mengyuan Qiao
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Yingling Nie
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Yurong He
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Jingyi Cheng
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| | - Yubing Dai
- Department of Neurosurgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, 550004, China
| | - Yu Li
- Department of Pathology, Chongqing Medical University, Chongqing, 400016, China.,Center for Molecular Medicine Testing, Chongqing Medical University, Chongqing, 400016, China
| |
Collapse
|
52
|
High-Fructose Consumption Impairs the Redox System and Protein Quality Control in the Brain of Syrian Hamsters: Therapeutic Effects of Melatonin. Mol Neurobiol 2018; 55:7973-7986. [DOI: 10.1007/s12035-018-0967-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/16/2018] [Indexed: 02/06/2023]
|
53
|
Ochalek A, Mihalik B, Avci HX, Chandrasekaran A, Téglási A, Bock I, Giudice ML, Táncos Z, Molnár K, László L, Nielsen JE, Holst B, Freude K, Hyttel P, Kobolák J, Dinnyés A. Neurons derived from sporadic Alzheimer's disease iPSCs reveal elevated TAU hyperphosphorylation, increased amyloid levels, and GSK3B activation. ALZHEIMERS RESEARCH & THERAPY 2017; 9:90. [PMID: 29191219 PMCID: PMC5709977 DOI: 10.1186/s13195-017-0317-z] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/27/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is the most common type of dementia, affecting one in eight adults over 65 years of age. The majority of AD cases are sporadic, with unknown etiology, and only 5% of all patients with AD present the familial monogenic form of the disease. In the present study, our aim was to establish an in vitro cell model based on patient-specific human neurons to study the pathomechanism of sporadic AD. METHODS We compared neurons derived from induced pluripotent stem cell (iPSC) lines of patients with early-onset familial Alzheimer's disease (fAD), all caused by mutations in the PSEN1 gene; patients with late-onset sporadic Alzheimer's disease (sAD); and three control individuals without dementia. The iPSC lines were differentiated toward mature cortical neurons, and AD pathological hallmarks were analyzed by RT-qPCR, enzyme-linked immunosorbent assay, and Western blotting methods. RESULTS Neurons from patients with fAD and patients with sAD showed increased phosphorylation of TAU protein at all investigated phosphorylation sites. Relative to the control neurons, neurons derived from patients with fAD and patients with sAD exhibited higher levels of extracellular amyloid-β 1-40 (Aβ1-40) and amyloid-β 1-42 (Aβ1-42). However, significantly increased Aβ1-42/Aβ1-40 ratios, which is one of the pathological markers of fAD, were observed only in samples of patients with fAD. Additionally, we detected increased levels of active glycogen synthase kinase 3 β, a physiological kinase of TAU, in neurons derived from AD iPSCs, as well as significant upregulation of amyloid precursor protein (APP) synthesis and APP carboxy-terminal fragment cleavage. Moreover, elevated sensitivity to oxidative stress, as induced by amyloid oligomers or peroxide, was detected in both fAD- and sAD-derived neurons. CONCLUSIONS On the basis of the experiments we performed, we can conclude there is no evident difference except secreted Aβ1-40 levels in phenotype between fAD and sAD samples. To our knowledge, this is the first study in which the hyperphosphorylation of TAU protein has been compared in fAD and sAD iPSC-derived neurons. Our findings demonstrate that iPSC technology is suitable to model both fAD and sAD and may provide a platform for developing new treatment strategies for these conditions.
Collapse
Affiliation(s)
- Anna Ochalek
- Molecular Animal Biotechnology Laboratory, Szent István University, H-2100, Gödöllő, Hungary.,BioTalentum Ltd., Aulich Lajos Street 26, H-2100, Gödöllő, Hungary
| | - Balázs Mihalik
- BioTalentum Ltd., Aulich Lajos Street 26, H-2100, Gödöllő, Hungary
| | - Hasan X Avci
- BioTalentum Ltd., Aulich Lajos Street 26, H-2100, Gödöllő, Hungary.,Department of Anatomy, Embryology and Histology, Faculty of Medicine, University of Szeged, H-6700, Szeged, Hungary.,Present address: University Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, 72076, Tübingen, Germany
| | | | | | - István Bock
- BioTalentum Ltd., Aulich Lajos Street 26, H-2100, Gödöllő, Hungary
| | - Maria Lo Giudice
- BioTalentum Ltd., Aulich Lajos Street 26, H-2100, Gödöllő, Hungary
| | - Zsuzsanna Táncos
- BioTalentum Ltd., Aulich Lajos Street 26, H-2100, Gödöllő, Hungary
| | - Kinga Molnár
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, H-1117, Budapest, Hungary
| | - Lajos László
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, H-1117, Budapest, Hungary
| | - Jørgen E Nielsen
- Neurogenetics Clinic & Research Laboratory, Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | | | - Kristine Freude
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870, Copenhagen, Denmark
| | - Poul Hyttel
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870, Copenhagen, Denmark
| | - Julianna Kobolák
- BioTalentum Ltd., Aulich Lajos Street 26, H-2100, Gödöllő, Hungary
| | - András Dinnyés
- Molecular Animal Biotechnology Laboratory, Szent István University, H-2100, Gödöllő, Hungary. .,BioTalentum Ltd., Aulich Lajos Street 26, H-2100, Gödöllő, Hungary.
| |
Collapse
|
54
|
Giacomelli C, Daniele S, Martini C. Potential biomarkers and novel pharmacological targets in protein aggregation-related neurodegenerative diseases. Biochem Pharmacol 2017; 131:1-15. [PMID: 28159621 DOI: 10.1016/j.bcp.2017.01.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 01/26/2017] [Indexed: 10/20/2022]
Abstract
The aggregation of specific proteins plays a pivotal role in the etiopathogenesis of several neurodegenerative diseases (NDs). β-Amyloid (Aβ) peptide-containing plaques and intraneuronal neurofibrillary tangles composed of hyperphosphorylated protein tau are the two main neuropathological lesions in Alzheimer's disease. Meanwhile, Parkinson's disease is defined by the presence of intraneuronal inclusions (Lewy bodies), in which α-synuclein (α-syn) has been identified as a major protein component. The current literature provides considerable insights into the mechanisms underlying oligomeric-related neurodegeneration, as well as the relationship between protein aggregation and ND, thus facilitating the development of novel putative biomarkers and/or pharmacological targets. Recently, α-syn, tau and Aβ have been shown to interact each other or with other "pathological proteins" to form toxic heteroaggregates. These latest findings are overcoming the concept that each neurodegenerative disease is related to the misfolding of a single specific protein. In this review, potential opportunities and pharmacological approaches targeting α-syn, tau and Aβ and their oligomeric forms are highlighted with examples from recent studies. Protein aggregation as a biomarker of NDs, in both the brain and peripheral fluids, is deeply explored. Finally, the relationship between biomarker establishment and assessment and their use as diagnostics or therapeutic targets are discussed.
Collapse
Affiliation(s)
- Chiara Giacomelli
- Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Simona Daniele
- Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy.
| |
Collapse
|
55
|
Ontiveros-Torres MÁ, Labra-Barrios ML, Díaz-Cintra S, Aguilar-Vázquez AR, Moreno-Campuzano S, Flores-Rodríguez P, Luna-Herrera C, Mena R, Perry G, Florán-Garduño B, Luna-Muñoz J, Luna-Arias JP. Fibrillar Amyloid-β Accumulation Triggers an Inflammatory Mechanism Leading to Hyperphosphorylation of the Carboxyl-Terminal End of Tau Polypeptide in the Hippocampal Formation of the 3×Tg-AD Transgenic Mouse. J Alzheimers Dis 2017; 52:243-69. [PMID: 27031470 DOI: 10.3233/jad-150837] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) is a degenerative and irreversible disorder whose progressiveness is dependent on age. It is histopathologically characterized by the massive accumulation of insoluble forms of tau and amyloid-β (Aβ) asneurofibrillary tangles and neuritic plaques, respectively. Many studies have documented that these two polypeptides suffer several posttranslational modifications employing postmortem tissue sections from brains of patients with AD. In order to elucidate the molecular mechanisms underlying the posttranslational modifications of key players in this disease, including Aβ and tau, several transgenic mouse models have been developed. One of these models is the 3×Tg-AD transgenic mouse, carrying three transgenes encoding APPSWE, S1M146V, and TauP301L proteins. To further characterize this transgenicmouse, we determined the accumulation of fibrillar Aβ as a function of age in relation to the hyperphosphorylation patterns of TauP301L at both its N- and C-terminus in the hippocampal formation by immunofluorescence and confocal microscopy. Moreover, we searched for the expression of activated protein kinases and mediators of inflammation by western blot of wholeprotein extracts from hippocampal tissue sections since 3 to 28 months as well. Our results indicate that the presence of fibrillar Aβ deposits correlates with a significant activation of astrocytes and microglia in subiculum and CA1 regions of hippocampus. Accordingly, we also observed a significant increase in the expression of TNF-α associated to neuritic plaques and glial cells. Importantly, there is an overexpression of the stress activated protein kinases SAPK/JNK and Cdk-5 in pyramidal neurons, which might phosphorylate several residues at the C-terminus of TauP301L. Therefore, the accumulation of Aβ oligomers results in an inflammatory environment that upregulates kinases involved in hyperphosphorylation of TauP301L polypeptide.
Collapse
Affiliation(s)
- Miguel Ángel Ontiveros-Torres
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Col. San Pedro Zacatenco, Ciudad de México, México
| | - María Luisa Labra-Barrios
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Col. San Pedro Zacatenco, Ciudad de México, México
| | - Sofía Díaz-Cintra
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Juriquilla, Querétaro, Qro., México
| | | | - Samadhi Moreno-Campuzano
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Col. San Pedro Zacatenco, Ciudad de México, México
| | - Paola Flores-Rodríguez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Col. San Pedro Zacatenco, Ciudad de México, México.,Present address: Departamento de Fisiología, Facultad de Medicina y Nutrición, Universidad Juárez del Estado de Durango, Durango, Dgo., México
| | - Claudia Luna-Herrera
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Campus Zacatenco, Ciudad de México, México
| | - Raúl Mena
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Col. San Pedro Zacatenco, Ciudad de México, México
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Benjamín Florán-Garduño
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Col. San Pedro Zacatenco, Ciudad de México, México
| | - José Luna-Muñoz
- Banco Nacional de Cerebros, Laboratorio Nacional de Servicios Experimentales, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Col. San Pedro Zacatenco, Ciudad de México, México
| | - Juan Pedro Luna-Arias
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Col. San Pedro Zacatenco, Ciudad de México, México
| |
Collapse
|
56
|
Yu C, Gao J, Zhou Y, Chen X, Xiao R, Zheng J, Liu Y, Zhou H. Deep Phosphoproteomic Measurements Pinpointing Drug Induced Protective Mechanisms in Neuronal Cells. Front Physiol 2016; 7:635. [PMID: 28066266 PMCID: PMC5179568 DOI: 10.3389/fphys.2016.00635] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 12/05/2016] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive and irreversible neurological disorder that impairs the living quality of old population and even life spans. New compounds have shown potential inneuroprotective effects in AD, such as GFKP-19, a 2-pyrrolidone derivative which has been proved to enhance the memory of dysmnesia mouse. The molecular mechanisms remain to be established for these drug candidates. Large-scale phosphoproteomic approach has been evolved rapidly in the last several years, which holds the potential to provide a useful toolkit to understand cellular signaling underlying drug effects. To establish and test such a method, we accurately analyzed the deep quantitative phosphoproteome of the neuro-2a cells treated with and without GFKP-19 using triple SILAC labeling. A total of 14,761 Class I phosphosites were quantified between controls, damaged, and protected conditions using the high resolution mass spectrometry, with a decent inter-mass spectrometer reproducibility for even subtle regulatory events. Our data suggests that GFKP-19 can reverse Aβ25−35 induced phosphorylation change in neuro-2a cells, and might protect the neuron system in two ways: firstly, it may decrease oxidative damage and inflammation induced by NO via down regulating the phosphorylation of nitric oxide synthase NOS1 at S847; Secondly, it may decrease tau protein phosphorylation through down-regulating the phosphorylation level of MAPK14 at T180. All mass spectrometry data are available via ProteomeXchange with identifier PXD005312.
Collapse
Affiliation(s)
- Chengli Yu
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of SciencesShanghai, China; College of Pharmacy, University of Chinese Academy of Sciences, Chinese Academy of SciencesBeijing, China
| | - Jing Gao
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai, China
| | - Yanting Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of SciencesShanghai, China; Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and TechnologyShanghai, China
| | - Xiangling Chen
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of SciencesShanghai, China; College of Pharmacy, University of Chinese Academy of Sciences, Chinese Academy of SciencesBeijing, China
| | - Ruoxuan Xiao
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of SciencesShanghai, China; College of Pharmacy, University of Chinese Academy of Sciences, Chinese Academy of SciencesBeijing, China
| | - Jing Zheng
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology Shanghai, China
| | - Yansheng Liu
- Department of Biology, Institute of Molecular Systems Biology, Swiss Federal Institute of Technology in Zurich Zurich, Switzerland
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of SciencesShanghai, China; College of Pharmacy, University of Chinese Academy of Sciences, Chinese Academy of SciencesBeijing, China
| |
Collapse
|
57
|
Clark JA, Yeaman EJ, Blizzard CA, Chuckowree JA, Dickson TC. A Case for Microtubule Vulnerability in Amyotrophic Lateral Sclerosis: Altered Dynamics During Disease. Front Cell Neurosci 2016; 10:204. [PMID: 27679561 PMCID: PMC5020100 DOI: 10.3389/fncel.2016.00204] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/15/2016] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an aggressive multifactorial disease converging on a common pathology: the degeneration of motor neurons (MNs), their axons and neuromuscular synapses. This vulnerability and dysfunction of MNs highlights the dependency of these large cells on their intracellular machinery. Neuronal microtubules (MTs) are intracellular structures that facilitate a myriad of vital neuronal functions, including activity dependent axonal transport. In ALS, it is becoming increasingly apparent that MTs are likely to be a critical component of this disease. Not only are disruptions in this intracellular machinery present in the vast majority of seemingly sporadic cases, recent research has revealed that mutation to a microtubule protein, the tubulin isoform TUBA4A, is sufficient to cause a familial, albeit rare, form of disease. In both sporadic and familial disease, studies have provided evidence that microtubule mediated deficits in axonal transport are the tipping point for MN survivability. Axonal transport deficits would lead to abnormal mitochondrial recycling, decreased vesicle and mRNA transport and limited signaling of key survival factors from the neurons peripheral synapses, causing the characteristic peripheral "die back". This disruption to microtubule dependant transport in ALS has been shown to result from alterations in the phenomenon of microtubule dynamic instability: the rapid growth and shrinkage of microtubule polymers. This is accomplished primarily due to aberrant alterations to microtubule associated proteins (MAPs) that regulate microtubule stability. Indeed, the current literature would argue that microtubule stability, particularly alterations in their dynamics, may be the initial driving force behind many familial and sporadic insults in ALS. Pharmacological stabilization of the microtubule network offers an attractive therapeutic strategy in ALS; indeed it has shown promise in many neurological disorders, ALS included. However, the pathophysiological involvement of MTs and their functions is still poorly understood in ALS. Future investigations will hopefully uncover further therapeutic targets that may aid in combating this awful disease.
Collapse
Affiliation(s)
- Jayden A Clark
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| | - Elise J Yeaman
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| | - Catherine A Blizzard
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| | - Jyoti A Chuckowree
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| | - Tracey C Dickson
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| |
Collapse
|
58
|
Arendt T, Stieler JT, Holzer M. Tau and tauopathies. Brain Res Bull 2016; 126:238-292. [DOI: 10.1016/j.brainresbull.2016.08.018] [Citation(s) in RCA: 333] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/31/2016] [Accepted: 08/31/2016] [Indexed: 12/11/2022]
|
59
|
The Effects of Alpha Boswellic Acid on Reelin Expression and Tau Phosphorylation in Human Astrocytes. Neuromolecular Med 2016; 19:136-146. [PMID: 27567921 DOI: 10.1007/s12017-016-8437-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 08/16/2016] [Indexed: 10/21/2022]
Abstract
Reelin is an extracellular glycoprotein which contributes to synaptic plasticity and function of memory in the adult brain. It has been indicated that the Reelin signaling cascade participates in Alzheimer's disease (AD). Besides the neurons, glial cells such as astrocytes also express Reelin protein. While functional loss of astrocytes has been reported to be associated with AD, dysfunction of astrocytic Reelin signaling pathway has not received much attention. Therefore, we investigated the effects of α-boswellic acid (ABA) as one of the major component of Boswellia serrata resin on primary fetal human astrocytes under a stress paradigm as a possible model for AD through study on Reelin cascade. For this aim, we used streptozotocin (STZ), in which from an outlook generates Alzheimer's hallmarks in astrocytes, and assayed Reelin expression, Tau and Akt phosphorylation as well as reactive oxygen species (ROS) generation and apoptosis in the presences of ABA. Our results indicated that while STZ (100 µM) down-regulated the expression of Reelin, ABA (25 µM) up-regulated its expression (p < 0.01) for 24 h. ABA efficiently reduced hyperphosphorylated Tau (Ser404) in STZ-treated astrocytes (p < 0.01). Furthermore, STZ-induced apoptosis by increasing cleaved caspase three (p < 0.01) and ROS generation (p < 0.01), a further pathological hallmark of Tauopathy. On the other hand, ABA decreased ROS generation and promoted proliferation of astrocytes through elevating Survivin expression (p < 0.01). These results showed that ABA could be considered as a potent therapeutic agent for prevention and decreasing the progression of Alzheimer's hallmarks in astrocytes; however, more in vivo studies would be needed.
Collapse
|
60
|
Szewczyk LM, Brozko N, Nagalski A, Röckle I, Werneburg S, Hildebrandt H, Wisniewska MB, Kuznicki J. ST8SIA2 promotes oligodendrocyte differentiation and the integrity of myelin and axons. Glia 2016; 65:34-49. [PMID: 27534376 PMCID: PMC5129544 DOI: 10.1002/glia.23048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/18/2016] [Accepted: 08/01/2016] [Indexed: 12/19/2022]
Abstract
ST8SIA2 is a polysialyltransferase that attaches polysialic acid to the glycoproteins NCAM1 and CADM1. Polysialylation is involved in brain development and plasticity. ST8SIA2 is a schizophrenia candidate gene, and St8sia2−/− mice exhibit schizophrenia‐like behavior. We sought to identify new pathological consequences of ST8SIA2 deficiency. Our proteomic analysis suggested myelin impairment in St8sia2−/− mice. Histological and immune staining together with Western blot revealed that the onset of myelination was not delayed in St8sia2−/− mice, but the content of myelin was lower. Ultrastructure analysis of the corpus callosum showed thinner myelin sheaths, smaller and irregularly shaped axons, and white matter lesions in adult St8sia2−/− mice. Then we evaluated oligodendrocyte differentiation in vivo and in vitro. Fewer OLIG2+ cells in the cortex and corpus callosum, together with the higher percentage of undifferentiated oligodenroglia in St8sia2−/− mice suggested an impairment in oligodendrocyte generation. Experiment on primary cultures of oligodendrocyte precursor cells (OPCs) confirmed a cell‐autonomous effect of ST8SIA2 in oligodendroglia, and demonstrated that OPC to oligodendrocyte transition is inhibited in St8sia2−/− mice. Concluding, ST8SIA2‐mediated polysialylation influences on oligodendrocyte differentiation, and oligodendrocyte deficits in St8sia2 mice are a possible cause of the demyelination and degeneration of axons, resembling nerve fiber alterations in schizophrenia. GLIA 2016;65:34–49
Collapse
Affiliation(s)
- Lukasz Mateusz Szewczyk
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, ul. Ks. Trojdena 4, Warszawa, 02-109, Poland.,Laboratory of Molecular Neurobiology, Centre of New Technologies, University of Warsaw, ul. Banacha 2C, Warszawa, 02-097, Poland.,Postgraduate School of Molecular Medicine, ul. Zwirki i Wigury 61, Warszawa, 02-091, Poland
| | - Nikola Brozko
- Laboratory of Molecular Neurobiology, Centre of New Technologies, University of Warsaw, ul. Banacha 2C, Warszawa, 02-097, Poland.,Postgraduate School of Molecular Medicine, ul. Zwirki i Wigury 61, Warszawa, 02-091, Poland
| | - Andrzej Nagalski
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, ul. Ks. Trojdena 4, Warszawa, 02-109, Poland
| | - Iris Röckle
- Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany
| | - Sebastian Werneburg
- Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany
| | - Herbert Hildebrandt
- Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany
| | - Marta Barbara Wisniewska
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, ul. Ks. Trojdena 4, Warszawa, 02-109, Poland.,Laboratory of Molecular Neurobiology, Centre of New Technologies, University of Warsaw, ul. Banacha 2C, Warszawa, 02-097, Poland
| | - Jacek Kuznicki
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, ul. Ks. Trojdena 4, Warszawa, 02-109, Poland
| |
Collapse
|
61
|
Regulation of Microtubule Assembly by Tau and not by Pin1. J Mol Biol 2016; 428:1742-59. [PMID: 26996940 DOI: 10.1016/j.jmb.2016.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 11/21/2022]
Abstract
The molecular mechanism by which the microtubule-associated protein (MAP) tau regulates the formation of microtubules (MTs) is poorly understood. The activity of tau is controlled via phosphorylation at specific Ser/Thr sites. Of those phosphorylation sites, 17 precede a proline, making them potential recognition sites for the peptidyl-prolyl isomerase Pin1. Pin1 binding and catalysis of phosphorylated tau at the AT180 epitope, which was implicated in Alzheimer's disease, has been reported to be crucial for restoring tau's ability to promote MT polymerization in vitro and in vivo [1]. Surprisingly, we discover that Pin1 does not promote phosphorylated tau-induced MT formation in vitro, refuting the commonly accepted model in which Pin1 binding and catalysis on the A180 epitope restores the function of the Alzheimer's associated phosphorylated tau in tubulin assembly [1, 2]. Using turbidity assays, time-resolved small angle X-ray scattering (SAXS), and time-resolved negative stain electron microscopy (EM), we investigate the mechanism of tau-mediated MT assembly and the role of the Thr231 and Ser235 phosphorylation on this process. We discover novel GTP-tubulin ring-shaped species, which are detectable in the earliest stage of tau-induced polymerization and may play a crucial role in the early nucleation phase of MT assembly. Finally, by NMR and SAXS experiments, we show that the tau molecules must be located on the surface of MTs and tubulin rings during the polymerization reaction. The interaction between tau and tubulin is multipartite, with a high affinity interaction of the four tubulin-binding repeats, and a weaker interaction with the proline-rich sequence and the termini of tau.
Collapse
|
62
|
Czapski GA, Gąssowska M, Wilkaniec A, Chalimoniuk M, Strosznajder JB, Adamczyk A. The mechanisms regulating cyclin-dependent kinase 5 in hippocampus during systemic inflammatory response: The effect on inflammatory gene expression. Neurochem Int 2016; 93:103-12. [PMID: 26806339 DOI: 10.1016/j.neuint.2016.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 01/15/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022]
Abstract
Cyclin-dependent kinase 5 (Cdk5) is critical for nervous system's development and function, and its aberrant activation contributes to pathomechanism of Alzheimer's disease and other neurodegenerative disorders. It was recently suggested that Cdk5 may participate in regulation of inflammatory signalling. The aim of this study was to analyse the mechanisms involved in regulating Cdk5 activity in the brain during systemic inflammatory response (SIR) as well as the involvement of Cdk5 in controlling the expression of inflammatory genes. Genetic and biochemical alterations in hippocampus were analysed 3 and 12 h after intraperitoneal injection of lipopolysaccharide. We observed an increase in both Cdk5 gene expression and protein level. Moreover, phosphorylation of Cdk5 on Ser159 was significantly enhanced. Also transcription of Cdk5-regulatory protein (p35/Cdk5r1) was augmented, and the level of p25, calpain-dependent cleavage product of p35, was increased. All these results demonstrated rapid activation of Cdk5 in the brain during SIR. Hyperactivity of Cdk5 contributed to enhanced phosphorylation of tau and glycogen synthase kinase 3β. Inhibition of Cdk5 with Roscovitine reduced activation of NF-κB and expression of inflammation-related genes, demonstrating the critical role of Cdk5 in regulation of gene transcription during SIR.
Collapse
Affiliation(s)
- Grzegorz A Czapski
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland.
| | - Magdalena Gąssowska
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Anna Wilkaniec
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Małgorzata Chalimoniuk
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Joanna B Strosznajder
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Agata Adamczyk
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, ul. Pawińskiego 5, 02-106 Warsaw, Poland
| |
Collapse
|
63
|
Determination of the Best Concentration of Streptozotocin to Create a Diabetic Brain Using Histological Techniques. J Mol Neurosci 2016; 59:24-35. [DOI: 10.1007/s12031-015-0702-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 12/11/2015] [Indexed: 11/25/2022]
|
64
|
Tau Hyperphosphorylation and Oxidative Stress, a Critical Vicious Circle in Neurodegenerative Tauopathies? OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:151979. [PMID: 26576216 PMCID: PMC4630413 DOI: 10.1155/2015/151979] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/08/2015] [Indexed: 12/14/2022]
Abstract
Hyperphosphorylation and aggregation of the microtubule-associated protein tau in brain, are pathological hallmarks of a large family of neurodegenerative disorders, named tauopathies, which include Alzheimer's disease. It has been shown that increased phosphorylation of tau destabilizes tau-microtubule interactions, leading to microtubule instability, transport defects along microtubules, and ultimately neuronal death. However, although mutations of the MAPT gene have been detected in familial early-onset tauopathies, causative events in the more frequent sporadic late-onset forms and relationships between tau hyperphosphorylation and neurodegeneration remain largely elusive. Oxidative stress is a further pathological hallmark of tauopathies, but its precise role in the disease process is poorly understood. Another open question is the source of reactive oxygen species, which induce oxidative stress in brain neurons. Mitochondria have been classically viewed as a major source for oxidative stress, but microglial cells were recently identified as reactive oxygen species producers in tauopathies. Here we review the complex relationships between tau pathology and oxidative stress, placing emphasis on (i) tau protein function, (ii) origin and consequences of reactive oxygen species production, and (iii) links between tau phosphorylation and oxidative stress. Further, we go on to discuss the hypothesis that tau hyperphosphorylation and oxidative stress are two key components of a vicious circle, crucial in neurodegenerative tauopathies.
Collapse
|
65
|
Xie S, Ogden A, Aneja R, Zhou J. Microtubule-Binding Proteins as Promising Biomarkers of Paclitaxel Sensitivity in Cancer Chemotherapy. Med Res Rev 2015; 36:300-12. [PMID: 26332739 DOI: 10.1002/med.21378] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/29/2015] [Accepted: 08/14/2015] [Indexed: 01/11/2023]
Abstract
Microtubules, tirelessly animated and highly dynamic structures, are vital for most cellular processes and their intricacies are still being revealed even after a century since their discovery. The importance of microtubules as chemotherapeutic targets cannot be overstated, and their clinical role is unlikely to abate in the near future. Indeed, improved understanding of microtubule biology could herald a new epoch of anticancer drug design by permitting fine-tuning of microtubule-targeting agents, the clinical utility of which is presently often limited by primary or acquired resistance. Paclitaxel, one such agent belonging to the taxane family, has proven a resoundingly successful treatment for many cancer patients; however, for too many others with paclitaxel-refractory tumors, the drug has offered nothing but side effects. Accumulating evidence suggests that microtubule-binding proteins (MBPs) can regulate paclitaxel sensitivity in a wide range of cancer types. Improved understanding of how these proteins can be assayed to predict treatment responses or manipulated pharmacologically to improve clinical outcomes could transform modern chemotherapy and is urgently awaited.
Collapse
Affiliation(s)
- Songbo Xie
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Angela Ogden
- Department of Biology, Georgia State University, Atlanta, GA, 30303
| | - Ritu Aneja
- Department of Biology, Georgia State University, Atlanta, GA, 30303
| | - Jun Zhou
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| |
Collapse
|
66
|
Effects of sodium bisulfite with or without procaine derivatives on axons of cultured mouse dorsal root ganglion neurons. Reg Anesth Pain Med 2015; 40:62-7. [PMID: 25493687 DOI: 10.1097/aap.0000000000000195] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND AND OBJECTIVES Sodium bisulfite (NaHSO3) was clinically used as a preservative agent for local anesthetics but was later suspected to be neurotoxic. However, recent studies reported that NaHSO3 reduces the neurotoxicity of local anesthetics. The purpose of this study was to examine the effects of NaHSO3 with and without procaine on axonal transport in cultured mouse dorsal root ganglion (DRG) neurons. METHODS Experiment 1 served to determine the dose-dependent effects of NaHSO3 on axonal transport (DRG neurons were treated with 0.01, 0.1, 1, 10, or 20 mM of NaHSO3), whereas experiment 2 investigated the effect of 0.1 mM NaHSO3 on the action of local anesthetics on axonal transport (DRG neurons were treated with 1 mM procaine alone, or with 0.1 mM NaHSO3 plus 1 mM procaine). As an additional experiment, DRG neurons were also treated with 1 mM chloroprocaine alone, or with 0.1 mM NaHSO3 plus 1 mM chloroprocaine. In these experiments, we analyzed the percent change in the number of anterogradely and retrogradely transported organelles and recorded changes in neurite morphology using video-enhanced microscopy. RESULTS In experiment 1, NaHSO3 at more than 1 mM caused cell membrane damage and complete inhibition of axonal transport, whereas 0.1 mM NaHSO3 maintained axonal transport at 40% to 60% of control with intact cell membrane. In experiment 2, 1 mM procaine alone maintained axonal transport at 90% to 100%. However, application of 1 mM procaine-0.1 mM NaHSO3 solution resulted in deformation of neurites and with complete cessation of axonal transport. Likewise, although 1 mM chloroprocaine maintain axonal transport at 80% to 100%, 1 mM chloroprocaine-0.1 mM NaHSO3 arrested axonal transport. CONCLUSIONS NaHSO3 resulted in a dose-dependent damage to the cell membrane and axonal transport, especially when used in combination with procaine or chloroprocaine.
Collapse
|
67
|
Yang H, Kim DS. Peptide Immunotherapy in Vaccine Development: From Epitope to Adjuvant. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 99:1-14. [PMID: 26067814 DOI: 10.1016/bs.apcsb.2015.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Vaccines are designed to educate the host immune system to prevent infectious disease or to fight against various diseases such as cancers. Peptides were first employed to provide specific immune responses while minimizing unintended allergenic or reactogenic adverse effects. Discoveries of virus or cancer-specific antigens and the advanced knowledge of immunology accelerate the peptide vaccine development. Despite the overwhelming research pipelines, a very few of them reached to market approvals or phase III clinical trials, because of the lack of efficacy. Several strategies for the next generation peptide vaccines are devised to overcome the weak immunogenicity and the poor delivery. In this review, we discuss the new promising strategies of peptide vaccine development which are recently developed in preclinical and/or clinical stage focusing the roles of peptides in the vaccine formulation from epitope to adjuvant. Additionally, we discuss the future perspectives of peptide vaccine and immunotherapy.
Collapse
Affiliation(s)
- Hyun Yang
- Research and Development Center, Peptron, Inc., Daejeon, South Korea
| | - Dong Seok Kim
- Research and Development Center, Peptron, Inc., Daejeon, South Korea.
| |
Collapse
|
68
|
Hansberg-Pastor V, González-Arenas A, Piña-Medina AG, Camacho-Arroyo I. Sex Hormones Regulate Cytoskeletal Proteins Involved in Brain Plasticity. Front Psychiatry 2015; 6:165. [PMID: 26635640 PMCID: PMC4653291 DOI: 10.3389/fpsyt.2015.00165] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 11/02/2015] [Indexed: 01/22/2023] Open
Abstract
In the brain of female mammals, including humans, a number of physiological and behavioral changes occur as a result of sex hormone exposure. Estradiol and progesterone regulate several brain functions, including learning and memory. Sex hormones contribute to shape the central nervous system by modulating the formation and turnover of the interconnections between neurons as well as controlling the function of glial cells. The dynamics of neuron and glial cells morphology depends on the cytoskeleton and its associated proteins. Cytoskeletal proteins are necessary to form neuronal dendrites and dendritic spines, as well as to regulate the diverse functions in astrocytes. The expression pattern of proteins, such as actin, microtubule-associated protein 2, Tau, and glial fibrillary acidic protein, changes in a tissue-specific manner in the brain, particularly when variations in sex hormone levels occur during the estrous or menstrual cycles or pregnancy. Here, we review the changes in structure and organization of neurons and glial cells that require the participation of cytoskeletal proteins whose expression and activity are regulated by estradiol and progesterone.
Collapse
Affiliation(s)
- Valeria Hansberg-Pastor
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - Aliesha González-Arenas
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - Ana Gabriela Piña-Medina
- Unidad de Investigación en Reproducción Humana, Instituto Nacional de Perinatología-Facultad de Química, Universidad Nacional Autónoma de México , Mexico City , Mexico
| | - Ignacio Camacho-Arroyo
- Unidad de Investigación en Reproducción Humana, Instituto Nacional de Perinatología-Facultad de Química, Universidad Nacional Autónoma de México , Mexico City , Mexico
| |
Collapse
|
69
|
Mechanism of Oxidative Stress and Synapse Dysfunction in the Pathogenesis of Alzheimer's Disease: Understanding the Therapeutics Strategies. Mol Neurobiol 2014; 53:648-661. [PMID: 25511446 DOI: 10.1007/s12035-014-9053-6] [Citation(s) in RCA: 319] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/28/2014] [Indexed: 10/24/2022]
Abstract
Synapses are formed by interneuronal connections that permit a neuronal cell to pass an electrical or chemical signal to another cell. This passage usually gets damaged or lost in most of the neurodegenerative diseases. It is widely believed that the synaptic dysfunction and synapse loss contribute to the cognitive deficits in patients with Alzheimer's disease (AD). Although pathological hallmarks of AD are senile plaques, neurofibrillary tangles, and neuronal degeneration which are associated with increased oxidative stress, synaptic loss is an early event in the pathogenesis of AD. The involvement of major kinases such as mitogen-activated protein kinase (MAPK), extracellular receptor kinase (ERK), calmodulin-dependent protein kinase (CaMKII), glycogen synthase-3β (GSK-3β), cAMP response element-binding protein (CREB), and calcineurin is dynamically associated with oxidative stress-mediated abnormal hyperphosphorylation of tau and suggests that alteration of these kinases could exclusively be involved in the pathogenesis of AD. N-methyl-D-aspartate (NMDA) receptor (NMDAR) activation and beta amyloid (Aβ) toxicity alter the synapse function, which is also associated with protein phosphatase (PP) inhibition and tau hyperphosphorylation (two main events of AD). However, the involvement of oxidative stress in synapse dysfunction is poorly understood. Oxidative stress and free radical generation in the brain along with excitotoxicity leads to neuronal cell death. It is inferred from several studies that excitotoxicity, free radical generation, and altered synaptic function encouraged by oxidative stress are associated with AD pathology. NMDARs maintain neuronal excitability, Ca(2+) influx, and memory formation through mechanisms of synaptic plasticity. Recently, we have reported the mechanism of the synapse redox stress associated with NMDARs altered expression. We suggest that oxidative stress mediated through NMDAR and their interaction with other molecules might be a driving force for tau hyperphosphorylation and synapse dysfunction. Thus, understanding the oxidative stress mechanism and degenerating synapses is crucial for the development of therapeutic strategies designed to prevent AD pathogenesis.
Collapse
|
70
|
Insulin therapy modulates mitochondrial dynamics and biogenesis, autophagy and tau protein phosphorylation in the brain of type 1 diabetic rats. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1154-66. [PMID: 24747740 DOI: 10.1016/j.bbadis.2014.04.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 04/08/2014] [Accepted: 04/10/2014] [Indexed: 01/22/2023]
Abstract
The main purpose of this study was to examine whether streptozotocin (STZ)-induced type 1 diabetes (T1D) and insulin (INS) treatment affect mitochondrial function, fission/fusion and biogenesis, autophagy and tau protein phosphorylation in cerebral cortex from diabetic rats treated or not with INS. No significant alterations were observed in mitochondrial function as well as pyruvate levels, despite the significant increase in glucose levels observed in INS-treated diabetic rats. A significant increase in DRP1 protein phosphorylated at Ser616 residue was observed in the brain cortex of STZ rats. Also an increase in NRF2 protein levels and in the number of copies of mtDNA were observed in STZ diabetic rats, these alterations being normalized by INS. A slight decrease in LC3-II levels was observed in INS-treated rats when compared to STZ diabetic animals. An increase in tau protein phosphorylation at Ser396 residue was observed in STZ diabetic rats while INS treatment partially reversed that effect. Accordingly, a modest reduction in the activation of GSK3β and a significant increase in the activity of phosphatase 2A were found in INS-treated rats when compared to STZ diabetic animals. No significant alterations were observed in caspases 9 and 3 activity and synaptophysin and PSD95 levels. Altogether our results show that mitochondrial alterations induced by T1D seem to involve compensation mechanisms since no significant changes in mitochondrial function and synaptic integrity were observed in diabetic animals. In addition, INS treatment is able to normalize the alterations induced by T1D supporting the importance of INS signaling in the brain.
Collapse
|
71
|
Selvatici R, Marani L, Marino S, Siniscalchi A. In vitro mitochondrial failure and oxidative stress mimic biochemical features of Alzheimer disease. Neurochem Int 2013; 63:112-20. [DOI: 10.1016/j.neuint.2013.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/13/2013] [Accepted: 05/16/2013] [Indexed: 01/09/2023]
|
72
|
Zhang Y, She F, Li L, Chen C, Xu S, Luo X, Li M, He M, Yu Z. p25/CDK5 is partially involved in neuronal injury induced by radiofrequency electromagnetic field exposure. Int J Radiat Biol 2013; 89:976-84. [DOI: 10.3109/09553002.2013.817699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
73
|
Kamat PK, Rai S, Nath C. Okadaic acid induced neurotoxicity: An emerging tool to study Alzheimer's disease pathology. Neurotoxicology 2013; 37:163-72. [DOI: 10.1016/j.neuro.2013.05.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 04/25/2013] [Accepted: 05/03/2013] [Indexed: 12/18/2022]
|
74
|
Chen N, Yang H, Niu J, Liu S. Determination of kinetic parameters and structure-activity relationships of ginsenosides as inhibitors of cyclin-dependent kinase 5/p25 using ultra-pressure liquid chromatography with triple quadrupole tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:985-992. [PMID: 23592201 DOI: 10.1002/rcm.6537] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/31/2013] [Accepted: 02/06/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE Cyclin-dependent kinase 5 (cdk5) is a serine/threonine kinase that is reported to play an important role in the pathogenesis of Alzheimer's disease. Ginsenosides have beneficial effects on Alzheimer's disease in both in vivo and in vitro experiments, but the precise mechanisms are not yet entirely clear. METHODS In the present study, an ultrahigh-pressure liquid chromatography (UPLC) and triple quadrupole mass spectrometry (TQMS) assay was developed to study the activities of cdk5 for the first time. RESULTS The calibration curves showed a good linear behavior over the range 0.04 μM to 10 μM (y = 0.934x + 0.045, R(2) = 0.995) with product phosphorylated peptide (PKpTPKKAKKV). The screening results suggested that the inhibition activities of ginsenosides are related to their chemical structures. CONCLUSIONS The developed UPLC/TQMS-based method for determination of an inhibitor of cdk5/p25 is sensitive and reliable. The effect of ginsenosides on Alzheimer's disease may be involved with the regulation of activities of cdk5/p25.
Collapse
Affiliation(s)
- Ning Chen
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun Center of Mass Spectrometry, Changchun, China
| | | | | | | |
Collapse
|
75
|
Two different docetaxel resistant MCF-7 sublines exhibited different gene expression pattern. Mol Biol Rep 2011; 39:3505-16. [PMID: 21720762 DOI: 10.1007/s11033-011-1123-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 06/20/2011] [Indexed: 12/20/2022]
Abstract
The objective of the present study was to investigate gene expression pattern of two docetaxel resistant MCF-7 breast carcinoma sublines step wisely selected in 30 and 120 nM docetaxel. Cell proliferation assay was performed in order to demonstrate development of docetaxel resistance. cDNA microarray analysis was performed using Affymetrix(®) Human Genome U133 Plus 2.0 Arrays in duplicate experiments. Quantitative and semi-quantitative gene expression analysis was also performed to confirm gene expression analysis for selected genes. XTT results demonstrated that 30 (MCF-7/30nM DOC) and 120 nM (MCF-7/120nM DOC) docetaxel selected cells were 13- and 47-fold resistant, respectively. cDNA microarray analysis demonstrated that expression profiles of MCF-7 and MCF-7/30nM DOC were more similar to each other where expression profile of MCF-7/120nM DOC was different as examined by line graphs and scatter plots. 2,837 and 4,036 genes were significantly altered in 30 and 120 nM docetaxel resistant sublines, respectively. Among these, 849 genes were altered in common in two docetaxel resistant sublines. Antiapoptotic gene expression (e.g., Bcl-2 and APRIL) were noticeably altered in MCF-7/30nM DOC. However, docetaxel resistance in MCF-7/120nM DOC were more complicated with the involvement of ECM related gene expression, cytokine and growth factor signaling, ROS metabolism and EMT related gene expression together with higher level of MDR1 expression. Expression profiles in 30 and 120 nM docetaxel resistant sublines changed gradually with increasing resistance index. Drug resistance development seems to be step wise event in MCF-7 cells.
Collapse
|
76
|
Sun Y, Kim NH, Yang H, Kim SH, Huh SO. Lysophosphatidic acid induces neurite retraction in differentiated neuroblastoma cells via GSK-3β activation. Mol Cells 2011; 31:483-9. [PMID: 21499833 PMCID: PMC3887612 DOI: 10.1007/s10059-011-1036-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 03/10/2011] [Indexed: 11/27/2022] Open
Abstract
Lysophosphatidic acid (LPA) is a lipid growth factor that exerts diverse biological effects, including rapid neurite retraction and cell migration. Alterations in cell morphology, including neurite retraction, in neurodegenerative disorders such as Alzheimer's disease involve hyperphosphorylation of the cytoskeletal protein tau. Since LPA has been shown to induce neurite retraction in various cultured neural cells and the detailed underlying molecular mechanisms have not yet been elucidated, we investigated whether LPA induced neurite retraction through taumediated signaling pathways in differentiated neuroblastoma cells. When Neuro2a cells differentiated with retinoic acid (RA) were exposed to LPA, cells exhibited neurite retraction in a time-dependent manner. The retraction of neurites was accompanied by the phosphorylation of tau. The LPA-induced neurite retraction and tau phosphorylation in differentiated Neuro2a cells were significantly abolished by the glycogen synthase kinase-3β (GSK-3β) inhibitor lithium chloride. Interestingly, the LPA-stimulated tau phosphorylation and neurite retraction were markedly prevented by the administration of H89, an inhibitor of both cyclic-AMP dependent protein kinase (PKA) and cyclic-AMP response element-binding protein (CREB). Transfection of the dominant-negative CREBs, K-CREB and A-CREB, failed to prevent LPA-induced tau phosphorylation and neurite retraction in differentiated Neuro2a cells. Taken together, these results suggest that GSK-3β and PKA, rather than CREB, play important roles in tau phosphorylation and neurite retraction in LPA-stimulated differentiated Neuro2a cells.
Collapse
Affiliation(s)
- Yuanjie Sun
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chunchon 200-702, Korea
- Present address: Chinese Academy of Sciences, Institute of Biophysics, Beijing, 100101, People’s Republic of China
| | - Nam-Ho Kim
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chunchon 200-702, Korea
| | - Haijie Yang
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chunchon 200-702, Korea
| | - Seung-Hyuk Kim
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chunchon 200-702, Korea
| | - Sung-Oh Huh
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chunchon 200-702, Korea
| |
Collapse
|
77
|
Sy M, Kitazawa M, Medeiros R, Whitman L, Cheng D, Lane TE, Laferla FM. Inflammation induced by infection potentiates tau pathological features in transgenic mice. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2811-22. [PMID: 21531375 DOI: 10.1016/j.ajpath.2011.02.012] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 01/31/2011] [Accepted: 02/07/2011] [Indexed: 12/12/2022]
Abstract
Comorbidities that promote the progression of Alzheimer's disease (AD) remain to be uncovered and evaluated in animal models. Because elderly individuals are vulnerable to viral and bacterial infections, these microbial agents may be considered important comorbidities that could potentiate an already existing and tenuous inflammatory condition in the brain, accelerating cognitive decline, particularly if the cellular and molecular mechanisms can be defined. Researchers have recently demonstrated that triggering inflammation in the brain exacerbates tau pathological characteristics in animal models. Herein, we explore whether inflammation induced via viral infection, compared with inflammation induced via bacterial lipopolysaccharide, modulates AD-like pathological features in the 3xTg-AD mouse model and provide evidence to support the hypothesis that infectious agents may act as a comorbidity for AD. Our study shows that infection-induced acute or chronic inflammation significantly exacerbates tau pathological characteristics, with chronic inflammation leading to impairments in spatial memory. Tau phosphorylation was increased via a glycogen synthase kinase-3β-dependent mechanism, and there was a prominent shift of tau from the detergent-soluble to the detergent-insoluble fraction. During chronic inflammation, we found that inhibiting glycogen synthase kinase-3β activity with lithium reduced tau phosphorylation and the accumulation of insoluble tau and reversed memory impairments. Taken together, infectious agents that trigger central nervous system inflammation may serve as a comorbidity for AD, leading to cognitive impairments by a mechanism that involves exacerbation of tau pathological characteristics.
Collapse
Affiliation(s)
- Michael Sy
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California, USA
| | | | | | | | | | | | | |
Collapse
|
78
|
De Vos A, Anandhakumar J, Van den Brande J, Verduyckt M, Franssens V, Winderickx J, Swinnen E. Yeast as a model system to study tau biology. Int J Alzheimers Dis 2011; 2011:428970. [PMID: 21559193 PMCID: PMC3090044 DOI: 10.4061/2011/428970] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 01/21/2011] [Indexed: 11/20/2022] Open
Abstract
Hyperphosphorylated and aggregated human protein tau constitutes a hallmark of a multitude of neurodegenerative diseases called tauopathies, exemplified by Alzheimer's disease. In spite of an enormous amount of research performed on tau biology, several crucial questions concerning the mechanisms of tau toxicity remain unanswered. In this paper we will highlight some of the processes involved in tau biology and pathology, focusing on tau phosphorylation and the interplay with oxidative stress. In addition, we will introduce the development of a human tau-expressing yeast model, and discuss some crucial results obtained in this model, highlighting its potential in the elucidation of cellular processes leading to tau toxicity.
Collapse
Affiliation(s)
- Ann De Vos
- Laboratory of Functional Biology, Catholic University of Leuven, Kasteelpark Arenberg 31, 3001 Heverlee, Belgium
| | - Jayamani Anandhakumar
- Laboratory of Functional Biology, Catholic University of Leuven, Kasteelpark Arenberg 31, 3001 Heverlee, Belgium
| | - Jeff Van den Brande
- Laboratory of Functional Biology, Catholic University of Leuven, Kasteelpark Arenberg 31, 3001 Heverlee, Belgium
| | - Mathias Verduyckt
- Laboratory of Functional Biology, Catholic University of Leuven, Kasteelpark Arenberg 31, 3001 Heverlee, Belgium
| | - Vanessa Franssens
- Laboratory of Functional Biology, Catholic University of Leuven, Kasteelpark Arenberg 31, 3001 Heverlee, Belgium
| | - Joris Winderickx
- Laboratory of Functional Biology, Catholic University of Leuven, Kasteelpark Arenberg 31, 3001 Heverlee, Belgium
| | - Erwin Swinnen
- Laboratory of Functional Biology, Catholic University of Leuven, Kasteelpark Arenberg 31, 3001 Heverlee, Belgium
| |
Collapse
|
79
|
Guthrie CR, Kraemer BC. Proteasome inhibition drives HDAC6-dependent recruitment of tau to aggresomes. J Mol Neurosci 2011; 45:32-41. [PMID: 21340680 DOI: 10.1007/s12031-011-9502-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 02/01/2011] [Indexed: 11/26/2022]
Abstract
Lesions containing aggregated and hyperphosphorylated tau protein are characteristic of neurodegenerative tauopathies. We have developed a cellular model of pathological tau deposition and clearance by overexpressing wild type human tau in HEK293 cells. When proteasome activity is inhibited, HEK293/tau cells accumulate tau protein in structures that bear many of the hallmarks of aggresomes. These include recruitment of tau into large spherical inclusions, accumulation of the retrograde motor protein dynein at the centrosome, formation of an intermediate filament cage around inclusions, and clustering of mitochondria at the aggresome. Tau aggresomes form rapidly and can be cleared upon relief of proteasome inhibition. We observe recruitment of pathological misfolded phospho-tau species to aggresomes. Immunoblotting reveals accumulation of detergent insoluble aggregated tau species. Knockdown of histone deacetylase 6, a protein known to interact with tau, reveals a requirement for HDAC6 activity in tau aggresome formation. Direct observation of the accumulation and clearance of abnormal tau species will allow us to dissect the cellular and molecular mechanisms at work in clearing aggresomal tau and its similarity to disease relevant pathological tau clearance mechanisms.
Collapse
Affiliation(s)
- Chris R Guthrie
- Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | | |
Collapse
|
80
|
Xu J, Sato S, Okuyama S, Swan RJ, Jacobsen MT, Strunk E, Ikezu T. Tau‐tubulin kinase 1 enhances prefibrillar tau aggregation and motor neuron degeneration in P301L FTDP‐17 tau‐mutant mice. FASEB J 2010; 24:2904-15. [DOI: 10.1096/fj.09-150144] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Jiqing Xu
- Department of Pharmacology and Experimental NeuroscienceCenter for Neurodegenerative DisordersUniversity of Nebraska Medical Center Omaha Nebraska USA
| | - Shinji Sato
- Department of Pharmacology and Experimental NeuroscienceCenter for Neurodegenerative DisordersUniversity of Nebraska Medical Center Omaha Nebraska USA
| | - Satoshi Okuyama
- Department of Pharmacology and Experimental NeuroscienceCenter for Neurodegenerative DisordersUniversity of Nebraska Medical Center Omaha Nebraska USA
| | - Russell J. Swan
- Department of Pharmacology and Experimental NeuroscienceCenter for Neurodegenerative DisordersUniversity of Nebraska Medical Center Omaha Nebraska USA
| | - Michael T. Jacobsen
- Department of Pharmacology and Experimental NeuroscienceCenter for Neurodegenerative DisordersUniversity of Nebraska Medical Center Omaha Nebraska USA
| | - Elena Strunk
- Department of Pharmacology and Experimental NeuroscienceCenter for Neurodegenerative DisordersUniversity of Nebraska Medical Center Omaha Nebraska USA
| | - Tsuneya Ikezu
- Department of Pharmacology and Experimental NeuroscienceCenter for Neurodegenerative DisordersUniversity of Nebraska Medical Center Omaha Nebraska USA
| |
Collapse
|
81
|
Poon WW, Blurton-Jones M, Tu CH, Feinberg LM, Chabrier MA, Harris JW, Jeon NL, Cotman CW. β-Amyloid impairs axonal BDNF retrograde trafficking. Neurobiol Aging 2009; 32:821-33. [PMID: 19540623 DOI: 10.1016/j.neurobiolaging.2009.05.012] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 05/07/2009] [Accepted: 05/08/2009] [Indexed: 12/17/2022]
Abstract
The neurotrophin, brain-derived neurotrophic factor (BDNF), is essential for synaptic function, plasticity and neuronal survival. At the axon terminal, when BDNF binds to its receptor, tropomyosin-related kinase B (TrkB), the signal is propagated along the axon to the cell body, via retrograde transport, regulating gene expression and neuronal function. Alzheimer disease (AD) is characterized by early impairments in synaptic function that may result in part from neurotrophin signaling deficits. Growing evidence suggests that soluble β-amyloid (Aβ) assemblies cause synaptic dysfunction by disrupting both neurotransmitter and neurotrophin signaling. Utilizing a novel microfluidic culture chamber, we demonstrate a BDNF retrograde signaling deficit in AD transgenic mouse neurons (Tg2576) that can be reversed by γ-secretase inhibitors. Using BDNF-GFP, we show that BDNF-mediated TrkB retrograde trafficking is impaired in Tg2576 axons. Furthermore, Aβ oligomers alone impair BDNF retrograde transport. Thus, Aβ reduces BDNF signaling by impairing axonal transport and this may underlie the synaptic dysfunction observed in AD.
Collapse
Affiliation(s)
- Wayne W Poon
- Institute for Brain Aging and Dementia, University of California, Irvine, 1226 Gillespie NRF, Irvine, CA 92697, United States.
| | | | | | | | | | | | | | | |
Collapse
|
82
|
Gendron TF, Petrucelli L. The role of tau in neurodegeneration. Mol Neurodegener 2009; 4:13. [PMID: 19284597 PMCID: PMC2663562 DOI: 10.1186/1750-1326-4-13] [Citation(s) in RCA: 312] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Accepted: 03/11/2009] [Indexed: 01/31/2023] Open
Abstract
Since the identification of tau as the main component of neurofibrillary tangles in Alzheimer's disease and related tauopathies, and the discovery that mutations in the tau gene cause frontotemporal dementia, much effort has been directed towards determining how the aggregation of tau into fibrillar inclusions causes neuronal death. As evidence emerges that tau-mediated neuronal death can occur even in the absence of tangle formation, a growing number of studies are focusing on understanding how abnormalities in tau (e.g. aberrant phosphorylation, glycosylation or truncation) confer toxicity. Though data obtained from experimental models of tauopathies strongly support the involvement of pathologically modified tau and tau aggregates in neurodegeneration, the exact neurotoxic species remain unclear, as do the mechanism(s) by which they cause neuronal death. Nonetheless, it is believed that tau-mediated neurodegeneration is likely to result from a combination of toxic gains of function as well as from the loss of normal tau function. To truly appreciate the detrimental consequences of aberrant tau function, a better understanding of all functions carried out by tau, including but not limited to the role of tau in microtubule assembly and stabilization, is required. This review will summarize what is currently known regarding the involvement of tau in the initiation and development of neurodegeneration in tauopathies, and will also highlight some of the remaining questions in need of further investigation.
Collapse
Affiliation(s)
- Tania F Gendron
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, USA.
| | | |
Collapse
|
83
|
Hanes J, Zilka N, Bartkova M, Caletkova M, Dobrota D, Novak M. Rat tau proteome consists of six tau isoforms: implication for animal models of human tauopathies. J Neurochem 2009; 108:1167-76. [PMID: 19141083 DOI: 10.1111/j.1471-4159.2009.05869.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human brain encompasses six tau isoforms, containing either three (3R) or four (4R) repeat domains, all of which participate in the pathogenesis of human tauopathies. To investigate the role of tau protein in the disease, transgenic rat models have been created. However, unlike humans, it has been suggested that rat brain expresses only three 4R tau isoforms. Because of the significance of the number of tau isoforms for faithful reproducibility of neurofibrillary pathology in transgenic rat models, we reopened this issue. Surprisingly, our results showed that adult rat brain contains six tau isoforms like humans. Protein expression of 4R tau isoforms was ninefold higher than 3R isoforms. Furthermore, the protein levels of tau isoforms with none, one or two N-terminal inserts were 30%, 35%, and 35% of total tau, respectively. Moreover, amount and ratio of tau isoforms were developmentally regulated. The levels of 4R tau isoforms progressively increased from early postnatal period until adulthood, whereas the expression of 3R tau isoforms reached maximum at P10 and then gradually declined. Our results show that rat brain encompasses full tau proteome similar to humans. These findings support the use of rat as an animal model in human tauopathies research.
Collapse
Affiliation(s)
- Jozef Hanes
- Axon Neuroscience GmbH, Rennweg, Vienna, Austria
| | | | | | | | | | | |
Collapse
|
84
|
Nicotinamide restores cognition in Alzheimer's disease transgenic mice via a mechanism involving sirtuin inhibition and selective reduction of Thr231-phosphotau. J Neurosci 2008; 28:11500-10. [PMID: 18987186 DOI: 10.1523/jneurosci.3203-08.2008] [Citation(s) in RCA: 265] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Memory loss is the signature feature of Alzheimer's disease, and therapies that prevent or delay its onset are urgently needed. Effective preventive strategies likely offer the greatest and most widespread benefits. Histone deacetylase (HDAC) inhibitors increase histone acetylation and enhance memory and synaptic plasticity. We evaluated the efficacy of nicotinamide, a competitive inhibitor of the sirtuins or class III NAD(+)-dependent HDACs in 3xTg-AD mice, and found that it restored cognitive deficits associated with pathology. Nicotinamide selectively reduces a specific phospho-species of tau (Thr231) that is associated with microtubule depolymerization, in a manner similar to inhibition of SirT1. Nicotinamide also dramatically increased acetylated alpha-tubulin, a primary substrate of SirT2, and MAP2c, both of which are linked to increased microtubule stability. Reduced phosphoThr231-tau was related to a reduction of monoubiquitin-conjugated tau, suggesting that this posttranslationally modified form of tau may be rapidly degraded. Overexpression of a Thr231-phospho-mimic tau in vitro increased clearance and decreased accumulation of tau compared with wild-type tau. These preclinical findings suggest that oral nicotinamide may represent a safe treatment for AD and other tauopathies, and that phosphorylation of tau at Thr231 may regulate tau stability.
Collapse
|
85
|
Amniai L, Barbier P, Sillen A, Wieruszeski JM, Peyrot V, Lippens G, Landrieu I. Alzheimer disease specific phosphoepitopes of Tau interfere with assembly of tubulin but not binding to microtubules. FASEB J 2008; 23:1146-52. [PMID: 19074508 DOI: 10.1096/fj.08-121590] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In Alzheimer disease (AD)-affected neurons, the Tau protein is found in an aggregated and hyperphosphorylated state. A common hypothesis is that Tau hyperphosphorylation causes its dissociation from the microtubular surface, with consequently a breakdown of the microtubules (MTs) and aggregation of the unbound Tau. We evaluated the effect of Tau phosphorylation on both tubulin assembly and MT binding. We show that the cyclin-dependent kinase 2/cyclin A3 kinase complex can generate the AT8 and AT180 AD-specific phospho-epitopes and use NMR spectroscopy to validate qualitatively and quantitatively the phospho content of our samples. The simultaneous presence of both epitopes disables the tubulin assembly capacity of Tau in conditions whereby Tau is the driving force for the assembly process but does not, however, inhibit MT assembly when the latter is driven by an increased tubulin concentration. When compared to the isolated MT binding repeats (K(d)=0.3 microM), the phospho-Tau retains a substantial affinity for preformed MTs (K(d)=11 nM), suggesting that the phosphorylated proline-rich region still participates in the binding event. Our results hence indicate that the sole phosphorylation at the AT8/AT180 epitopes, although leading to a functional defect for Tau, is not sufficient for its dissociation from the MT surface and subsequent aggregation as observed in AD.
Collapse
Affiliation(s)
- Laziza Amniai
- Université des Sciences et Technologies de Lille 1, Villeneuve d'Ascq, France
| | | | | | | | | | | | | |
Collapse
|
86
|
Leptin reduces Alzheimer's disease-related tau phosphorylation in neuronal cells. Biochem Biophys Res Commun 2008; 376:536-41. [PMID: 18801339 DOI: 10.1016/j.bbrc.2008.09.026] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 09/06/2008] [Indexed: 12/31/2022]
Abstract
Leptin is a centrally acting hormone controlling metabolic pathways. Recently, it was shown that leptin can reduce amyloid beta levels both in vitro and in vivo. Herein, phosphorylation of tau was investigated following treatment of neuronal cells with leptin and insulin. Specifically, phosphorylation of tau at amino acid residues Ser(202), Ser(396) and Ser(404) was monitored in retinoic acid induced, human cell lines: SH-SY5Y and NTera-2. Both hormones induced a concentration- and time-dependent reduction of tau phosphorylation, and were synergistic at suboptimum concentrations. Importantly, leptin was 300-fold more potent than insulin (IC(50)L=46.9 nM vs. IC(50)I=13.8 microM). A central role for AMP-dependent kinase as a mediator of leptin's action is demonstrated by the ability of 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) to decrease tau phosphorylation, and by blocking leptin in the presence of Compound C. Thus, leptin, which ameliorates both amyloid beta and tau-related pathological pathways, holds promise as a novel therapeutic for Alzheimer's disease.
Collapse
|
87
|
Wang JZ, Liu F. Microtubule-associated protein tau in development, degeneration and protection of neurons. Prog Neurobiol 2008; 85:148-75. [PMID: 18448228 DOI: 10.1016/j.pneurobio.2008.03.002] [Citation(s) in RCA: 286] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 12/29/2007] [Accepted: 03/13/2008] [Indexed: 12/11/2022]
Abstract
As a principal neuronal microtubule-associated protein, tau has been recognized to play major roles in promoting microtubule assembly and stabilizing the microtubules and to maintain the normal morphology of the neurons. Recent studies suggest that tau, upon alternative mRNA splicing and multiple posttranslational modifications, may participate in the regulations of intracellular signal transduction, development and viability of the neurons. Furthermore, tau gene mutations, aberrant mRNA splicing and abnormal posttranslational modifications, such as hyperphosphorylation, have also been found in a number of neurodegenerative disorders, collectively known as tauopathies. Therefore, changes in expression of the tau gene, alternative splicing of its mRNA and its posttranslational modification can modulate the normal architecture and functions of neurons as well as in a situation of tauopathies, such as Alzheimer's disease. The primary aim of this review is to summarize the latest developments and perspectives in our understanding about the roles of tau, especially hyperphosphorylation, in the development, degeneration and protection of neurons.
Collapse
Affiliation(s)
- Jian-Zhi Wang
- Pathophysiology Department, Hubei Provincial Key Laboratory of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China.
| | | |
Collapse
|
88
|
Caccamo A, Oddo S, Tran LX, LaFerla FM. Lithium reduces tau phosphorylation but not A beta or working memory deficits in a transgenic model with both plaques and tangles. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:1669-75. [PMID: 17456772 PMCID: PMC1854961 DOI: 10.2353/ajpath.2007.061178] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Glycogen synthase kinase 3 (GSK-3) is a major kinase implicated in the pathogenesis of Alzheimer's disease (AD), and reducing its activity may have therapeutic efficacy. Two variants exist, referred to as GSK-3 alpha and GSK-3beta. In addition to the latter's well-described role in the phosphorylation of tau, reports also suggest that GSK-3 alpha may regulate amyloid precursor protein processing and Abeta formation. The activities of both GSK-3 alpha and GSK-3beta are reduced by lithium, a well-tolerated drug used in humans to combat bipolar disorder. Here, we investigate the therapeutic efficacy of chronic lithium administration in aged 3xTg-AD mice that harbor both plaques and tangles. We found that lithium reduced tau phosphorylation but did not significantly alter the A beta load. Despite the reduction in phosphotau, lithium treatment did not improve deficits in working memory. Although other studies have investigated the effects of lithium on tau biochemistry, this study represents the first to address comprehensively its therapeutic potential on other critical aspects of AD including its effect on A beta and learning and memory. It remains to be determined from human clinical trials whether lithium treatment alone will improve the clinical outcome in AD patients. These results, however, suggest that the most efficacious treatment will be combining lithium with other anti-A beta interventions.
Collapse
Affiliation(s)
- Antonella Caccamo
- Department of Neurobiology and Behavior, University of California, Irvine, 1109 Gillespie Neuroscience Bldg., Irvine, CA 92697-4545, USA
| | | | | | | |
Collapse
|
89
|
Bandyopadhyay B, Li G, Yin H, Kuret J. Tau Aggregation and Toxicity in a Cell Culture Model of Tauopathy. J Biol Chem 2007; 282:16454-64. [PMID: 17428800 DOI: 10.1074/jbc.m700192200] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Intracellular aggregation of the microtubule-associated protein tau into filamentous inclusions is a defining characteristic of Alzheimer disease. Because appearance of tau-aggregate bearing lesions correlates with both cognitive decline and neurodegeneration, it has been hypothesized that tau aggregation may be directly toxic to cells that harbor them. Testing this hypothesis in cell culture has been complicated by the resistance of full-length tau isoforms to aggregation over experimentally tractable time periods. To overcome this limitation, a small-molecule agonist of the tau aggregation reaction, Congo red, was used to drive aggregation within HEK-293 cells expressing full-length tau isoform htau40. Formation of detergent-insoluble aggregates was both time and agonist concentration dependent. At 10 microM Congo red, detergent-insoluble aggregates appeared with pseudo-first order kinetics and a half-life of approximately 5 days. By 7 days in culture, total tau levels increased 2-fold, with approximately 30% of total tau converted into detergent-insoluble aggregates. Agonist addition also led to rapid losses in the tubulin binding activity of tau, although tau was not hyperphosphorylated as judged by occupancy of phosphorylation sites Ser396/Ser404. Tau aggregation was associated with decreased viability as detected by ToPro-3 uptake. The results, which establish a new approach for analysis of tau aggregation in cells independent of tau hyperphosphorylation, suggest that conformational changes associated with aggregation are incompatible with microtubule binding, and that toxicity associated with intracellular tau aggregation is not acute but develops over a period of days.
Collapse
Affiliation(s)
- Bhaswati Bandyopadhyay
- Center for Molecular Neurobiology, the Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus 43210, USA
| | | | | | | |
Collapse
|
90
|
Mwangi S, Anitha M, Fu H, Sitaraman SV, Srinivasan S. Glial cell line-derived neurotrophic factor-mediated enteric neuronal survival involves glycogen synthase kinase-3beta phosphorylation and coupling with 14-3-3. Neuroscience 2006; 143:241-51. [PMID: 16996218 DOI: 10.1016/j.neuroscience.2006.07.050] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 07/25/2006] [Accepted: 07/26/2006] [Indexed: 12/15/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) promotes the growth and survival of enteric neurons, but the mechanisms involved are poorly understood. GDNF is known to promote the survival of enteric neurons through activation of the PI3-Kinase/Akt signaling pathway. We investigated the role of glycogen synthase kinase-3beta (GSK-3beta) in enteric neuronal survival, and the ability of GDNF to regulate the activity of GSK-3beta using primary rat embryonic enteric neurons. GDNF, through activation of the PI3-kinase pathway enhanced the phosphorylation of GSK-3beta at its N-terminal serine-9 residue, and promoted the association of GSK-3beta with 14-3-3. Transfection of a constitutively active S9A-GSK-3beta mutant prevented the survival effects of GDNF, whereas a dominant negative GSK-3beta construct prevented GDNF withdrawal-induced cell death. Increased GSK-3beta activity was associated with an increase in tau phosphorylation. Thus, GDNF promotes enteric neuronal survival by modulating GSK-3beta and its downstream target tau. Inhibitors of GSK-3beta activity may have therapeutic potential in improving enteric neuronal survival.
Collapse
Affiliation(s)
- S Mwangi
- Division of Digestive Diseases, Department of Medicine, Emory University, Whitehead Research Building, Atlanta, GA 30322, USA
| | | | | | | | | |
Collapse
|
91
|
Kitazawa M, Oddo S, Yamasaki TR, Green KN, LaFerla FM. Lipopolysaccharide-induced inflammation exacerbates tau pathology by a cyclin-dependent kinase 5-mediated pathway in a transgenic model of Alzheimer's disease. J Neurosci 2006; 25:8843-53. [PMID: 16192374 PMCID: PMC6725603 DOI: 10.1523/jneurosci.2868-05.2005] [Citation(s) in RCA: 526] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Inflammation is a critical component of the pathogenesis of Alzheimer's disease (AD). Although not an initiator of this disorder, inflammation nonetheless plays a pivotal role as a driving force that can modulate the neuropathology. Here, we characterized the time course of microglia activation in the brains of a transgenic model of AD (3xTg-AD) and discerned its relationship to the plaque and tangle pathology. We find that microglia became activated in a progressive and age-dependent manner, and this activation correlated with the onset of fibrillar amyloidbeta-peptide plaque accumulation and tau hyperphosphorylation. To determine whether microglial activation can exacerbate the pathology, we exposed young 3xTg-AD mice to lipopolysaccharide (LPS), a known inducer of CNS inflammation. Although amyloid precursor protein processing appeared unaffected, we find that LPS significantly induced tau hyperphosphorylation at specific sites that were mediated by the activation of cyclin-dependent kinase 5 (cdk5) through increased formation of the p25 fragment. We further show that administration of roscovitine, a selective and potent inhibitor of cdk5, markedly blocked the LPS-induced tau phosphorylation in the hippocampus. Therefore, this study clearly demonstrates that microglial activation exacerbates key neuropathological features such as tangle formation.
Collapse
Affiliation(s)
- Masashi Kitazawa
- Department of Neurobiology and Behavior, University of California-Irvine, California 92697-4545, USA
| | | | | | | | | |
Collapse
|
92
|
Cotman CW, Poon WW, Rissman RA, Blurton-Jones M. The Role of Caspase Cleavage of Tau in Alzheimer Disease Neuropathology. J Neuropathol Exp Neurol 2005; 64:104-12. [PMID: 15751224 DOI: 10.1093/jnen/64.2.104] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Alzheimer disease (AD) is characterized by the accumulation of amyloid plaques and neurofibrillary tangles within selective brain regions. In addition, cell death pathways become active leading to neurodegeneration. Caspase activation, a key step in the programmed cell death pathway known as apoptosis, occurs in AD and leads to the proteolytic cleavage of several neuronal proteins. Previously, it was hypothesized that the development of the classical hallmarks of AD, amyloid plaques and neurofibrillary tangles, occur independently and do not involve the activation of caspases. However, recent studies suggest that plaques, tangles, and caspase activation share a common pathway. Beta-amyloid, the main component of amyloid plaques, activates caspases. Activated caspases can in turn cleave tau, the main component of neurofibrillary tangles. Caspase-cleaved tau (deltatau) may initiate or accelerate the development of tangle pathology. Tau, when cleaved by caspases at Asp421, "seeds" filamentous aggregates in vitro. Caspase-cleaved tau also adopts the MC1 conformation, one of the earliest pathologic events in tangle formation. Importantly, deltatau occurs early in the development of tangle pathology within AD brains and in a transgenic mouse model of AD. This review summarizes recent evidence suggesting that caspase cleavage of tau plays an important role in the development of neurofibrillary tangle pathology. In addition, a model is presented whereby caspase cleavage of tau provides a mechanistic link between the development of amyloid and tangle pathologies.
Collapse
Affiliation(s)
- Carl W Cotman
- Institute for Brain Aging and Dementia, University of California, Irvine, 92697, USA.
| | | | | | | |
Collapse
|
93
|
Ahn JS, Musacchio A, Mapelli M, Ni J, Scinto L, Stein R, Kosik KS, Yeh LA. Development of an assay to screen for inhibitors of tau phosphorylation by cdk5. ACTA ACUST UNITED AC 2004; 9:122-31. [PMID: 15006135 DOI: 10.1177/1087057103260594] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A high-throughput assay for tau phosphorylation by cdk5/p25 is described. Full-length recombinant tau was used as a substrate in the presence of saturating adenosine triphosphate (ATP). Using PHF-1, an antibody directed specifically against 2 tau phosphorylation epitopes (serine 396 and serine 404), an enzyme-linked immunosorbent assay (ELISA)-based colorimetric assay was formatted in 384-well plates. The assay was validated by measuring kinetic parameters for cdk5/p25 catalysis and known inhibitors. Rate constants for the site-specific phosphorylations at the PHF-1 epitopes were determined and suggested preferential phosphorylation at these sites. The performance of this assay in a high-throughput format was demonstrated and used to identify inhibitors of tau phosphorylation at specific epitopes phosphorylated by cdk5/p25.
Collapse
Affiliation(s)
- Jae Suk Ahn
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, USA
| | | | | | | | | | | | | | | |
Collapse
|
94
|
Li G, Yin H, Kuret J. Casein kinase 1 delta phosphorylates tau and disrupts its binding to microtubules. J Biol Chem 2004; 279:15938-45. [PMID: 14761950 DOI: 10.1074/jbc.m314116200] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tau hyperphosphorylation precedes neuritic lesion formation in Alzheimer's disease, suggesting it participates in the tau fibrillization reaction pathway. Candidate tau protein kinases include members of the casein kinase 1 (CK1) family of phosphotransferases, which are highly overexpressed in Alzheimer's disease brain and colocalize with neuritic and granulovacuolar lesions. Here we characterized the contribution of one CK1 isoform, Ckidelta, to the phosphorylation of tau at residues Ser202/Thr205 and Ser396/Ser404 in human embryonic kidney 293 cells using immunodetection and fluorescence microscopy. Treatment of cells with membrane permeable CK1 inhibitor 3-[(2,3,6-trimethoxyphenyl)methylidenyl]-indolin-2-one (IC261) lowered occupancy of Ser396/Ser404 phosphorylation sites by >70% at saturation, suggesting that endogenous CK1 was the major source of basal phosphorylation activity at these sites. Overexpression of Ckidelta increased CK1 enzyme activity and further raised tau phosphorylation at residues Ser202/Thr205 and Ser396/Ser404 in situ. Inhibitor IC261 reversed tau hyperphosphorylation induced by Ckidelta overexpression. Co-immunoprecipitation assays showed direct association of tau and Ckidelta in situ, consistent with tau being a Ckidelta substrate. Ckidelta overexpression also produced a decrease in the fraction of bulk tau bound to detergent-insoluble microtubules. These results suggest that Ckidelta phosphorylates tau at sites that modulate tau/microtubule binding, and that the expression pattern of Ckidelta in Alzheimer's disease is consistent with it playing an important role in tau aggregation.
Collapse
Affiliation(s)
- Guibin Li
- Center for Molecular Neurobiology, Ohio State Biochemistry Program, Ohio State University College of Medicine and Public Health, Columbus, Ohio 43210, USA
| | | | | |
Collapse
|
95
|
Identification of a novel, membrane-associated neuronal kinase, cyclin-dependent kinase 5/p35-regulated kinase. J Neurosci 2003. [PMID: 12832520 DOI: 10.1523/jneurosci.23-12-04975.2003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Here we characterize a novel neuronal kinase, cyclin-dependent kinase 5 (cdk5)/p35-regulated kinase (cprk). Cprk is a member of a previously undescribed family of kinases that are predicted to contain two N-terminal membrane-spanning domains and a long C terminus, which harbors a dual-specificity serine/threonine/tyrosine kinase domain. Cprk was isolated in a yeast two-hybrid screen using the neuronal cdk5 activator p35 as "bait." Cprk interacts with p35 in the yeast-two hybrid system, binds to p35 in glutathione S-transferase fusion pull-down assays, and colocalizes with p35 in cultured neurons and transfected cells. In these cells, cprk is present with p35 in the Golgi apparatus. Cprk is expressed in a number of tissues but is enriched in brain and muscle and within the brain is found in a wide range of neuronal populations. Cprk displays catalytic activity in in vitro kinase assays and is itself phosphorylated by cdk5/p35. Cdk5/p35 inhibits cprk activity. Cdk5/p35 may therefore regulate cprk function in the brain.
Collapse
|
96
|
Weishaupt JH, Neusch C, Bähr M. Cyclin-dependent kinase 5 (CDK5) and neuronal cell death. Cell Tissue Res 2003; 312:1-8. [PMID: 12684868 DOI: 10.1007/s00441-003-0703-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2002] [Accepted: 01/10/2003] [Indexed: 12/21/2022]
Abstract
Many neurological disorders like Parkinson's and Alzheimer's disease, amyotrophic lateral sclerosis (ALS) or stroke have in common a definite loss of CNS neurons due to apoptotic or necrotic neuronal cell death. Previous studies suggested that proapoptotic stimuli may trigger an abortive and, therefore, eventually fatal cell cycle reentry in postmitotic neurons. Neuroprotective effects of small molecule inhibitors of cyclin-dependent kinases (CDKs), which are key regulators of cell cycle progression, support the cell cycle theory of neuronal apoptosis. However, growing evidence suggests that deregulated CDK5, which is not involved in cell cycle control, rather than cell cycle relevant members of the CDK family, promotes neuronal cell death. Here we summarize the current knowledge about the involvement of CDK5 in neuronal cell death and discuss possible up- or downstream partners of CDK5. Moreover, we discuss potential therapeutic options that might arise from the identification of CDK5 as an important upstream element of neuronal cell death cascades.
Collapse
Affiliation(s)
- J H Weishaupt
- Department of Neurology, University Hospital Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | | | | |
Collapse
|
97
|
Takahashi S, Saito T, Hisanaga SI, Pant HC, Kulkarni AB. Tau phosphorylation by cyclin-dependent kinase 5/p39 during brain development reduces its affinity for microtubules. J Biol Chem 2003; 278:10506-15. [PMID: 12536148 DOI: 10.1074/jbc.m211964200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The microtubule-associated protein tau is a developmentally regulated neuronal phosphoprotein. The phosphorylation of tau reduces its ability to bind and stabilize axonal microtubules during axonal growth. Although tau is phosphorylated by cyclin-dependent kinase 5 (Cdk5) in vitro, its in vivo roles remain unclear. Here, we show that tau is phosphorylated by Cdk5/p39 during brain development, resulting in a reduction of its affinity for microtubules. The activity of Cdk5 is tightly regulated by association with its neuronal activators, p35 or p39. The p35 and p39 expression levels were investigated in the developing mouse brain; the p39 expression level was higher in embryonic hind brain and spinal cord and in postnatal cerebral cortex, whereas that of p35 was most prominent in cerebral cortex at earlier stages of development. The ability of Cdk5 to phosphorylate tau was higher when in association with p39 than in association with p35. Tau phosphorylation at Ser-202 and Thr-205 was decreased in Cdk5-/- mouse brain but not in p35-/- mouse brain, suggesting that Cdk5/p39 is responsible for the in vivo phosphorylation of tau at these sites. Our data suggest that tau phosphorylation by Cdk5 may provide the neuronal microtubules with dynamic properties in a region-specific and developmentally regulated manner.
Collapse
Affiliation(s)
- Satoru Takahashi
- Functional Genomics Unit, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | |
Collapse
|
98
|
Li G, Faibushevich A, Turunen BJ, Yoon SO, Georg G, Michaelis ML, Dobrowsky RT. Stabilization of the cyclin-dependent kinase 5 activator, p35, by paclitaxel decreases beta-amyloid toxicity in cortical neurons. J Neurochem 2003; 84:347-62. [PMID: 12558997 DOI: 10.1046/j.1471-4159.2003.01526.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
One hallmark of Alzheimer's disease (AD) is the formation of neurofibrillary tangles, aggregated paired helical filaments composed of hyperphosphorylated tau. Amyloid-beta (Abeta) induces tau hyperphosphorylation, decreases microtubule (MT) stability and induces neuronal death. MT stabilizing agents have been proposed as potential therapeutics that may minimize Abeta toxicity and here we report that paclitaxel (taxol) prevents cell death induced by Abeta peptides, inhibits Abeta-induced activation of cyclin-dependent kinase 5 (cdk5) and decreases tau hyperphosphorylation. Taxol did not inhibit cdk5 directly but significantly blocked Abeta-induced calpain activation and decreased formation of the cdk5 activator, p25, from p35. Taxol specifically inhibited the Abeta-induced activation of the cytosolic cdk5-p25 complex, but not the membrane-associated cdk5-p35 complex. MT-stabilization was necessary for neuroprotection and inhibition of cdk5 but was not sufficient to prevent cell death induced by overexpression of p25. As taxol is not permeable to the blood-brain barrier, we assessed the potential of taxanes to attenuate Abeta toxicity in adult animals using a succinylated taxol analog (TX67) permeable to the blood-brain barrier. TX67, but not taxol, attenuated the magnitude of both basal and Abeta-induced cdk5 activation in acutely dissociated cortical cultures prepared from drug treated adult mice. These results suggest that MT-stabilizing agents may provide a therapeutic approach to decrease Abeta toxicity and neurofibrillary pathology in AD and other tauopathies.
Collapse
Affiliation(s)
- Guibin Li
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence 66045, USA
| | | | | | | | | | | | | |
Collapse
|
99
|
Lau LF, Seymour PA, Sanner MA, Schachter JB. Cdk5 as a drug target for the treatment of Alzheimer's disease. J Mol Neurosci 2002; 19:267-73. [PMID: 12540052 DOI: 10.1385/jmn:19:3:267] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2002] [Accepted: 10/28/2002] [Indexed: 11/11/2022]
Abstract
Cyclin-dependent kinase-5 (cdk5) is suggested to play a role in tau phosphorylation and contribute to the pathogenesis of Alzheimer's disease (AD). One of its activators, p25, is dramatically increased in AD brains where p25 and cdk5 are colocalized with neurofibrillary tangles. Several animal models have shown a correlation of p25/cdk5 activities with tau phosphorylation. Overexpression of p25/cdk5 in nueronal cultures not only leads to tau phosphorylation but also cytoskeletal abnormalities and neurodegeneration. Therefore, cdk5 kinase inhibitors are potential therapeutic agents for the treatment of AD. Availability of potent, selective, brain permeable cdk5 inhibitors and relevant animal models in which their efficacy can be treated will be critical in the development of these inhibitors.
Collapse
Affiliation(s)
- Lit-Fui Lau
- CNS Discovery, Pfizer Global Research and Development, Groton, CT 06340, USA.
| | | | | | | |
Collapse
|
100
|
|