1
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Vihinen M. Systematic errors in annotations of truncations, loss-of-function and synonymous variants. Front Genet 2023; 14:1015017. [PMID: 36713076 PMCID: PMC9880313 DOI: 10.3389/fgene.2023.1015017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/03/2023] [Indexed: 01/15/2023] Open
Abstract
Description of genetic phenomena and variations requires exact language and concepts. Vast amounts of variation data are produced with next-generation sequencing pipelines. The obtained variations are automatically annotated, e.g., for their functional consequences. These tools and pipelines, along with systematic nomenclature, mainly work well, but there are still some problems in nomenclature, organization of some databases, misuse of concepts and certain practices. Therefore, systematic errors prevent correct annotation and often preclude further analysis of certain variation types. Problems and solutions are described for presumed protein truncations, variants that are claimed to be of loss-of-function based on the type of variation, and synonymous variants that are not synonymous and lead to sequence changes or to missing protein.
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2
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Sinsky J, Pichlerova K, Hanes J. Tau Protein Interaction Partners and Their Roles in Alzheimer's Disease and Other Tauopathies. Int J Mol Sci 2021; 22:9207. [PMID: 34502116 PMCID: PMC8431036 DOI: 10.3390/ijms22179207] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 02/06/2023] Open
Abstract
Tau protein plays a critical role in the assembly, stabilization, and modulation of microtubules, which are important for the normal function of neurons and the brain. In diseased conditions, several pathological modifications of tau protein manifest. These changes lead to tau protein aggregation and the formation of paired helical filaments (PHF) and neurofibrillary tangles (NFT), which are common hallmarks of Alzheimer's disease and other tauopathies. The accumulation of PHFs and NFTs results in impairment of physiological functions, apoptosis, and neuronal loss, which is reflected as cognitive impairment, and in the late stages of the disease, leads to death. The causes of this pathological transformation of tau protein haven't been fully understood yet. In both physiological and pathological conditions, tau interacts with several proteins which maintain their proper function or can participate in their pathological modifications. Interaction partners of tau protein and associated molecular pathways can either initiate and drive the tau pathology or can act neuroprotective, by reducing pathological tau proteins or inflammation. In this review, we focus on the tau as a multifunctional protein and its known interacting partners active in regulations of different processes and the roles of these proteins in Alzheimer's disease and tauopathies.
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Affiliation(s)
| | | | - Jozef Hanes
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska Cesta 9, 845 10 Bratislava, Slovakia; (J.S.); (K.P.)
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3
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Bell R, Vendruscolo M. Modulation of the Interactions Between α-Synuclein and Lipid Membranes by Post-translational Modifications. Front Neurol 2021; 12:661117. [PMID: 34335440 PMCID: PMC8319954 DOI: 10.3389/fneur.2021.661117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 05/18/2021] [Indexed: 12/14/2022] Open
Abstract
Parkinson's disease is characterised by the presence in brain tissue of aberrant inclusions known as Lewy bodies and Lewy neurites, which are deposits composed by α-synuclein and a variety of other cellular components, including in particular lipid membranes. The dysregulation of the balance between lipid homeostasis and α-synuclein homeostasis is therefore likely to be closely involved in the onset and progression of Parkinson's disease and related synucleinopathies. As our understanding of this balance is increasing, we describe recent advances in the characterisation of the role of post-translational modifications in modulating the interactions of α-synuclein with lipid membranes. We then discuss the impact of these advances on the development of novel diagnostic and therapeutic tools for synucleinopathies.
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Affiliation(s)
| | - Michele Vendruscolo
- Centre for Misfolding Disease, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
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4
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Yang CC, Luo Y, Guo KW, Zheng CC, Li L, Zhang L. Cornel Iridoid Glycoside Regulates Modification of Tau and Alleviates Synaptic Abnormalities in Aged P301S Mice. Curr Med Sci 2021; 40:1040-1046. [PMID: 33428131 DOI: 10.1007/s11596-020-2285-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/09/2020] [Indexed: 10/22/2022]
Abstract
Alzheimer's disease (AD), also defined as a tauopathology, is a common neurodegenerative disease. Hyper-phosphorylation, cleavage or truncation, and aggregation of tau contribute to AD. Thus, targeting the post-translational modifications on tau may be a therapeutic strategy to treat AD. This study understood how cornel iridoid glycoside (CIG) affects tau post-translational modifications and synaptic abnormalities. The 10-month old P301S tau transgenic mice were given CIG at 100 and 200 mg/kg every day orally for 1 month. Hyperphosphorylated and truncated tau, synapse-associated proteins and glutamatergic receptors were all detected using Western blotting. The interactions between Morroniside (MOR) or Loganin (LOG) and tau were detected using Autodock and Surface Plasmon Resonance (SPR). The effects of CIG on the aggregation of tau were investigated using a cell-free system. CIG attenuated tau hyperphosphorylation at Thr205, Ser212, Ser262, Thr231 and Ser235 (AT180), but had no effect on tau truncation in the brains of 10-month old P301S mice. Binding free energies and interactions revealed that MOR and LOG bound with tau. We also found that CIG upregulated synapse-associated proteins such as PSD-95, syntaxin1A and synaptotagmin. In addition, CIG restored N-methyl-D-aspartic acid receptor and glutamate receptor levels. CIG improves post-translational modification of tau as well as synaptic abnormalities. The data presented here reveal that CIG may be used in the treatment of AD.
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Affiliation(s)
- Cui-Cui Yang
- Department of Pharmacy, Xuanwu Hospital of Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing Engineering Research Center for Nervous System Drugs, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Beijing, 100053, China
| | - Yi Luo
- Department of Pharmacy, Xuanwu Hospital of Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing Engineering Research Center for Nervous System Drugs, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Beijing, 100053, China
| | - Kai-Wen Guo
- Department of Pharmacy, Xuanwu Hospital of Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing Engineering Research Center for Nervous System Drugs, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Beijing, 100053, China
| | - Ceng-Ceng Zheng
- Department of Pharmacy, Xuanwu Hospital of Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing Engineering Research Center for Nervous System Drugs, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Beijing, 100053, China
| | - Lin Li
- Department of Pharmacy, Xuanwu Hospital of Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing Engineering Research Center for Nervous System Drugs, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Beijing, 100053, China
| | - Lan Zhang
- Department of Pharmacy, Xuanwu Hospital of Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing Engineering Research Center for Nervous System Drugs, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Beijing, 100053, China.
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5
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Wang ZH, Wu W, Kang SS, Liu X, Wu Z, Peng J, Yu SP, Manfredsson FP, Sandoval IM, Liu X, Wang JZ, Ye K. BDNF inhibits neurodegenerative disease-associated asparaginyl endopeptidase activity via phosphorylation by AKT. JCI Insight 2018; 3:99007. [PMID: 30135302 DOI: 10.1172/jci.insight.99007] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 07/03/2018] [Indexed: 12/13/2022] Open
Abstract
AEP is an age-dependent lysosomal asparaginyl endopeptidase that cleaves numerous substrates including tau and α-synuclein and mediates their pathological roles in neurodegenerative diseases. However, the molecular mechanism regulating this critical protease remains incompletely understood. Here, we show that Akt phosphorylates AEP on residue T322 upon brain-derived neurotrophic factor (BDNF) treatment and triggers its lysosomal translocation and inactivation. When BDNF levels are reduced in neurodegenerative diseases, AEP T322 phosphorylation is attenuated. Consequently, AEP is activated and translocates into the cytoplasm, where it cleaves both tau and α-synuclein. Remarkably, the unphosphorylated T322A mutant increases tau or α-synuclein cleavage by AEP and augments cell death, whereas phosphorylation mimetic T322E mutant represses these effects. Interestingly, viral injection of T322E into Tau P301S mice antagonizes tau N368 cleavage and tau pathologies, rescuing synaptic dysfunction and cognitive deficits. By contrast, viral administration of T322A into young α-SNCA mice elicits α-synuclein N103 cleavage and promotes dopaminergic neuronal loss, facilitating motor defects. Therefore, our findings support the notion that BDNF contributes to the pathogenesis of neurodegenerative diseases by suppressing AEP via Akt phosphorylation.
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Affiliation(s)
- Zhi-Hao Wang
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.,Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wanqiang Wu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.,Laboratory of Functional Chemistry and Nutrition of Food, College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Seong Su Kang
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Xia Liu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Zhiping Wu
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Junmin Peng
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Shan Ping Yu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Fredric P Manfredsson
- Department of Translational Science & Molecular Medicine, Michigan State University, Grand Rapids, Michigan, USA
| | - Ivette M Sandoval
- Department of Translational Science & Molecular Medicine, Michigan State University, Grand Rapids, Michigan, USA
| | - Xuebo Liu
- Laboratory of Functional Chemistry and Nutrition of Food, College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
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6
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Skrabana R, Kovacech B, Filipcik P, Zilka N, Jadhav S, Smolek T, Kontsekova E, Novak M. Neuronal Expression of Truncated Tau Efficiently Promotes Neurodegeneration in Animal Models: Pitfalls of Toxic Oligomer Analysis. J Alzheimers Dis 2018; 58:1017-1025. [PMID: 28527208 DOI: 10.3233/jad-161124] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Animal models of neurodegeneration induced by neuronal expression of truncated tau protein emerge as an important tool for understanding the pathogenesis of human tauopathies and for therapy development. Here we highlight common features of truncated tau models and make a critical assessment of possible pitfalls in their analysis. Particularly, the amount of soluble tau oligomers, which are suspected to be neurotoxic agents participating on the spreading of pathology inside the brain, may be overestimated due to a post-lysis oxidative tau oligomerization. Using a mouse brain lysate spiked with recombinant truncated and full length tau forms, we show that tau oligomers might inadvertently be produced during the isolation procedure. This finding is further corroborated by the analysis of brain lysates originated from a mouse model expressing truncated tau variant. Our results underline the necessity of thiol-protecting conditions during the analysis of tau oligomers involved in the etiopathogenesis of various tauopathies including Alzheimer's disease.
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Affiliation(s)
- Rostislav Skrabana
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Branislav Kovacech
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Peter Filipcik
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Norbert Zilka
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Santosh Jadhav
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Tomas Smolek
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Eva Kontsekova
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia.,Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Michal Novak
- Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia.,AXON Neuroscience SE, Larnaca, Cyprus
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Zimova I, Brezovakova V, Hromadka T, Weisova P, Cubinkova V, Valachova B, Filipcik P, Jadhav S, Smolek T, Novak M, Zilka N. Human Truncated Tau Induces Mature Neurofibrillary Pathology in a Mouse Model of Human Tauopathy. J Alzheimers Dis 2018; 54:831-43. [PMID: 27567836 DOI: 10.3233/jad-160347] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) represents the most common neurodegenerative disorder. Several animal models have been developed in order to test pathophysiological mechanisms of the disease and to predict effects of pharmacological interventions. Here we examine the molecular and behavioral features of R3m/4 transgenic mice expressing human non-mutated truncated tau protein (3R tau, aa151-391) that were previously used for efficacy testing of passive tau vaccine. The mouse model reliably recapitulated crucial histopathological features of human AD, such as pre-tangles, neurofibrillary tangles, and neuropil threads. The pathology was predominantly located in the brain stem. Transgenic mice developed mature sarkosyl insoluble tau complexes consisting of mouse endogenous and human truncated and hyperphosphorylated forms of tau protein. The histopathological and biochemical features were accompanied by significant sensorimotor impairment and reduced lifespan. The sensorimotor impairment was monitored by a highly sensitive, fully-automated tool that allowed us to assess early deficit in gait and locomotion. We suggest that the novel transgenic mouse model can serve as a valuable tool for analysis of the therapeutic efficacy of tau vaccines for AD therapy.
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Affiliation(s)
- Ivana Zimova
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic
| | - Veronika Brezovakova
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic
| | - Tomas Hromadka
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic
| | | | - Veronika Cubinkova
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic
| | - Bernadeta Valachova
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic
| | - Peter Filipcik
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic
| | - Santosh Jadhav
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic
| | - Tomas Smolek
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic
| | - Michal Novak
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic.,Axon Neuroscience SE, Bratislava, Slovak Republic
| | - Norbert Zilka
- Institute of Neuroimmunology, Slovak Academy of Sciences, AD Centre, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic
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8
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Jantzie LL, Winer JL, Corbett CJ, Robinson S. Erythropoietin Modulates Cerebral and Serum Degradation Products from Excess Calpain Activation following Prenatal Hypoxia-Ischemia. Dev Neurosci 2015; 38:15-26. [PMID: 26551007 DOI: 10.1159/000441024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/10/2015] [Indexed: 01/20/2023] Open
Abstract
Preterm infants suffer central nervous system (CNS) injury from hypoxia-ischemia and inflammation - termed encephalopathy of prematurity. Mature CNS injury activates caspase and calpain proteases. Erythropoietin (EPO) limits apoptosis mediated by activated caspases, but its role in modulating calpain activation has not yet been investigated extensively following injury to the developing CNS. We hypothesized that excess calpain activation degrades developmentally regulated molecules essential for CNS circuit formation, myelination and axon integrity, including neuronal potassium-chloride co-transporter (KCC2), myelin basic protein (MBP) and phosphorylated neurofilament (pNF), respectively. Further, we predicted that post-injury EPO treatment could mitigate CNS calpain-mediated degradation. Using prenatal transient systemic hypoxia-ischemia (TSHI) in rats to mimic CNS injury from extreme preterm birth, and postnatal EPO treatment with a clinically relevant dosing regimen, we found sustained postnatal excess cortical calpain activation following prenatal TSHI, as shown by the cleavage of alpha II-spectrin (αII-spectrin) into 145-kDa αII-spectrin degradation products (αII-SDPs) and p35 into p25. Postnatal expression of the endogenous calpain inhibitor calpastatin was also reduced following prenatal TSHI. Calpain substrate expression following TSHI, including cortical KCC2, MBP and NF, was modulated by postnatal EPO treatment. Calpain activation was reflected in serum levels of αII-SDPs and KCC2 fragments, and notably, EPO treatment also modulated KCC2 fragment levels. Together, these data indicate that excess calpain activity contributes to the pathogenesis of encephalopathy of prematurity. Serum biomarkers of calpain activation may detect ongoing cerebral injury and responsiveness to EPO or similar neuroprotective strategies.
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Affiliation(s)
- Lauren L Jantzie
- Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, Mass., USA
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9
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DeForte S, Reddy KD, Uversky VN. Digested disorder, Quarterly intrinsic disorder digest (October-November-December, 2013). INTRINSICALLY DISORDERED PROTEINS 2015; 3:e984569. [PMID: 28293487 DOI: 10.4161/21690707.2014.984569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 10/09/2014] [Accepted: 10/10/2014] [Indexed: 11/19/2022]
Abstract
This is the 4th issue of the Digested Disorder series that represents reader's digest of the scientific literature on intrinsically disordered proteins. The only 2 criteria for inclusion in this digest are the publication date (a paper should be published within the covered time frame) and topic (a paper should be dedicated to any aspect of protein intrinsic disorder). The current digest issue covers papers published during the fourth quarter of 2013; i.e. during the period of October, November, and December of 2013. Similar to previous issues, the papers are grouped hierarchically by topics they cover, and for each of the included paper a short description is given on its major findings.
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Affiliation(s)
- Shelly DeForte
- Department of Molecular Medicine; Morsani College of Medicine; University of South Florida; Tampa, FL USA; These authors contributed equally to this work
| | - Krishna D Reddy
- Department of Molecular Medicine; Morsani College of Medicine; University of South Florida; Tampa, FL USA; These authors contributed equally to this work
| | - Vladimir N Uversky
- Department of Molecular Medicine; Morsani College of Medicine; University of South Florida; Tampa, FL USA; USF Health Byrd Alzheimer Research Institute; Morsani College of Medicine; University of South Florida; Tampa, FL USA; Biology Department; Faculty of Science; King Abdulaziz University; Jeddah, Kingdom of Saudi Arabia; Laboratory of Structural Dynamics, Stability, and Folding of Proteins; Institute of Cytology; Russian Academy of Sciences; St. Petersburg, Russia; Institute for Biological Instrumentation; Russian Academy of Sciences; Moscow Region, Russia
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10
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Kontsekova E, Zilka N, Kovacech B, Skrabana R, Novak M. Identification of structural determinants on tau protein essential for its pathological function: novel therapeutic target for tau immunotherapy in Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2014; 6:45. [PMID: 25478018 PMCID: PMC4255369 DOI: 10.1186/alzrt277] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 07/21/2014] [Indexed: 01/18/2023]
Abstract
Introduction Pathologically modified tau protein is the main feature of Alzheimer’s disease (AD) and related tauopathies. Therefore, immunotherapies that target mis-disordered tau represent a promising avenue for the disease-modifying treatment of AD. In this report, we present our discovery of (1) a novel target for tau immunotherapy; (2) monoclonal antibody DC8E8, which neutralizes this target; and (3) the results of efficacy studies of DC8E8 in a murine model of tauopathy. Methods In vitro tau oligomerisation assays were used for the selection of antibodies. The therapeutic efficacy of DC8E8 was evaluated in transgenic mice. The structure of the DC8E8 epitope was determined by X-ray crystallography. Results Screening of a panel of monoclonal antibodies for their inhibitory activity in an in vitro pathological tau–tau interaction assay yielded DC8E8, which reduced the amount of oligomeric tau by 84%. DC8E8 recognised all developmental stages of tau pathology in AD human brains, including pretangles and intra- and extracellular tangles. Treatment with DC8E8 in a mouse AD model expressing mis-disordered human tau significantly reduced the amount of insoluble oligomerised tau and the number of early and mature neurofibrillary tangles in the transgenic mouse brains. By using a panel of tau-derived peptides in a competitive enzyme-linked immunosorbent assay, we identified the tau domain essential for pathological tau–tau interaction, which is targeted by DC8E8. The antibody was capable of binding to four highly homologous and yet independent binding regions on tau, each of which is a separate epitope. The X-ray structure of the DC8E8 Fab apo form, solved at 3.0 Å, suggested that the four DC8E8 epitopes form protruding structures on the tau molecule. Finally, by kinetic measurements with surface plasmon resonance, we determined that antibody DC8E8 is highly discriminatory between pathological and physiological tau. Conclusions We have discovered defined determinants on mis-disordered truncated tau protein which are responsible for tau oligomerisation leading to neurofibrillary degeneration. Antibody DC8E8 reactive with these determinants is able to inhibit tau–tau interaction in vitro and in vivo. DC8E8 is able to discriminate between the healthy and diseased tau proteome, making its epitopes suitable targets, and DC8E8 a suitable candidate molecule, for AD immunotherapy.
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Affiliation(s)
- Eva Kontsekova
- Axon Neuroscience SE, Dvorakovo nabrezie 10, 811 02 Bratislava, Slovak Republic
| | - Norbert Zilka
- Axon Neuroscience SE, Dvorakovo nabrezie 10, 811 02 Bratislava, Slovak Republic
| | - Branislav Kovacech
- Axon Neuroscience SE, Dvorakovo nabrezie 10, 811 02 Bratislava, Slovak Republic ; Present address: Institute of Neuroimmunology, Dubravska cesta 9, 84510 Bratislava, Slovak Republic
| | - Rostislav Skrabana
- Axon Neuroscience SE, Dvorakovo nabrezie 10, 811 02 Bratislava, Slovak Republic
| | - Michal Novak
- Axon Neuroscience SE, Dvorakovo nabrezie 10, 811 02 Bratislava, Slovak Republic
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11
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Kumar A, Singh PK, Parihar R, Dwivedi V, Lakhotia SC, Ganesh S. Decreased O-linked GlcNAcylation protects from cytotoxicity mediated by huntingtin exon1 protein fragment. J Biol Chem 2014; 289:13543-53. [PMID: 24648514 DOI: 10.1074/jbc.m114.553321] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
O-GlcNAcylation is an important post-translational modification of proteins and is known to regulate a number of pathways involved in cellular homeostasis. This involves dynamic and reversible modification of serine/threonine residues of different cellular proteins catalyzed by O-linked N-acetylglucosaminyltransferase and O-linked N-acetylglucosaminidase in an antagonistic manner. We report here that decreasing O-GlcNAcylation enhances the viability of neuronal cells expressing polyglutamine-expanded huntingtin exon 1 protein fragment (mHtt). We further show that O-GlcNAcylation regulates the basal autophagic process and that suppression of O-GlcNAcylation significantly increases autophagic flux by enhancing the fusion of autophagosome with lysosome. This regulation considerably reduces toxic mHtt aggregates in eye imaginal discs and partially restores rhabdomere morphology and vision in a fly model for Huntington disease. This study is significant in unraveling O-GlcNAcylation-dependent regulation of an autophagic process in mediating mHtt toxicity. Therefore, targeting the autophagic process through the suppression of O-GlcNAcylation may prove to be an important therapeutic approach in Huntington disease.
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Affiliation(s)
- Amit Kumar
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016 and
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