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Sarabia-Vallejo Á, López-Alvarado P, Menéndez JC. Small-molecule theranostics in Alzheimer's disease. Eur J Med Chem 2023; 255:115382. [PMID: 37141706 DOI: 10.1016/j.ejmech.2023.115382] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 05/06/2023]
Abstract
Alzheimer's Disease (AD) remains one of the most challenging health-related issues for our society. It is becoming increasingly prevalent, especially in developed countries, due to the rising life expectancy and, moreover, represents a considerable economic burden worldwide. All efforts at the discovery of new diagnostic and therapeutic tools in the last decades have invariably met with failure, making AD an incurable illness and underscoring the need for new approaches. In recent years, theranostic agents have emerged as an interesting strategy. They are molecules able to simultaneously provide diagnostic information and deliver therapeutic activity, allowing for the assessment of the molecule activity, the organism response and the pharmacokinetics. This makes these compounds promising for streamlining research on AD drugs and for their application in personalized medicine. We review here the field of small-molecule theranostic agents as promising tools for the development of novel diagnostic and therapeutic resources against AD, highlighting the positive and significant impact that theranostics can be expected to have in the near future in clinical practice.
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Affiliation(s)
- Álvaro Sarabia-Vallejo
- Unidad de Química Orgánica y Farmacéutica, Departamento de Química en Ciencias Farmacéuticas, Facultad de Farmacia, Universidad Complutense, 28040, Madrid, Spain
| | - Pilar López-Alvarado
- Unidad de Química Orgánica y Farmacéutica, Departamento de Química en Ciencias Farmacéuticas, Facultad de Farmacia, Universidad Complutense, 28040, Madrid, Spain
| | - J Carlos Menéndez
- Unidad de Química Orgánica y Farmacéutica, Departamento de Química en Ciencias Farmacéuticas, Facultad de Farmacia, Universidad Complutense, 28040, Madrid, Spain.
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2
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Šmidlehner T, Bonnet H, Chierici S, Piantanida I. Fluorescently-labelled amyloid paired helical filaments (PHF) in monitoring its fibrillation kinetics. Bioorg Chem 2020; 104:104196. [DOI: 10.1016/j.bioorg.2020.104196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/13/2020] [Accepted: 08/15/2020] [Indexed: 10/23/2022]
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3
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Shimonaka S, Matsumoto SE, Elahi M, Ishiguro K, Hasegawa M, Hattori N, Motoi Y. Asparagine residue 368 is involved in Alzheimer's disease tau strain-specific aggregation. J Biol Chem 2020; 295:13996-14014. [PMID: 32759167 DOI: 10.1074/jbc.ra120.013271] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/14/2020] [Indexed: 02/06/2023] Open
Abstract
In tauopathies, tau forms pathogenic fibrils with distinct conformations (termed "tau strains") and acts as an aggregation "seed" templating the conversion of normal tau into isomorphic fibrils. Previous research showed that the aggregation core of tau fibril covers the C-terminal region (243-406 amino acids (aa)) and differs among the diseases. However, the mechanisms by which distinct fibrous structures are formed and inherited via templated aggregation are still unknown. Here, we sought to identify the key sequences of seed-dependent aggregation. To identify sequences for which deletion reduces tau aggregation, SH-SY5Y cells expressing a series of 10 partial deletion (Del 1-10, covering 244-400 aa) mutants of tau-CTF24 (243-441 aa) were treated with tau seeds prepared from a different tauopathy patient's brain (Alzheimer's disease, progressive supranuclear palsy, and corticobasal degeneration) or recombinant tau, and then seed-dependent tau aggregation was assessed biochemically. We found that the Del 8 mutant lacking 353-368 aa showed significantly decreased aggregation in both cellular and in vitro models. Furthermore, to identify the minimum sequence responsible for tau aggregation, we systematically repeated cellular tau aggregation assays for the delineation of shorter deletion sites and revealed that Asn-368 mutation suppressed tau aggregation triggered by an AD tau seed, but not using other tauopathy seeds. Our study suggested that 353-368 aa is a novel aggregation-responsible sequence other than PHF6 and PHF6*, and within this sequence, the Asn-368 residue plays a role in strain-specific tau aggregation in different tauopathies.
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Affiliation(s)
- Shotaro Shimonaka
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Diagnosis, Prevention, and Treatment of Dementia, Juntendo University School of Medicine, Tokyo, Japan
| | - Shin-Ei Matsumoto
- Department of Immunology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Montasir Elahi
- Department of Diagnosis, Prevention, and Treatment of Dementia, Juntendo University School of Medicine, Tokyo, Japan.,Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
| | - Koichi Ishiguro
- Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
| | - Masato Hasegawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Nobutaka Hattori
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
| | - Yumiko Motoi
- Department of Diagnosis, Prevention, and Treatment of Dementia, Juntendo University School of Medicine, Tokyo, Japan .,Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
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4
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Gorantla NV, Das R, Mulani FA, Thulasiram HV, Chinnathambi S. Neem Derivatives Inhibits Tau Aggregation. J Alzheimers Dis Rep 2019; 3:169-178. [PMID: 31259310 PMCID: PMC6597962 DOI: 10.3233/adr-190118] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tau is a phosphoprotein with natively unfolded conformation that functions to stabilize microtubules in axons. Alzheimer’s disease pathology triggers several modifications in tau, which causes it to lose its affinity towards microtubule, thus, leading to microtubule disassembly and loss of axonal integrity. This elicit accumulation of tau as paired helical filaments is followed by stable neurofibrillary tangles formation. A large number of small molecules have been isolated from Azadirachta indica with varied medicinal applications. The intermediate and final limonoids, nimbin and salannin respectively, isolated from Azadirachta indica, were screened against tau aggregation. ThS and ANS fluorescence assay showed the role of intermediate and final limonoids in preventing heparin induced cross-β sheet formation and also decreased hydrophobicity, which are characteristic nature of tau aggregation. Transmission electron microscopy studies revealed that limonoids restricted the aggregation of tau to fibrils; in turn, limonoids led to the formation of short and fragile aggregates. Both the limonoids were non-toxic to HEK293T cells thus, substantiating limonoids as a potential lead in overcoming Alzheimer’s disease.
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Affiliation(s)
- Nalini V Gorantla
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, India
| | - Rashmi Das
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, India
| | - Fayaj A Mulani
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, India
| | - Hirekodathakallu V Thulasiram
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, India
| | - Subashchandrabose Chinnathambi
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, India
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5
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Martin MD, Calcul L, Smith C, Jinwal UK, Fontaine SN, Darling A, Seeley K, Wojtas L, Narayan M, Gestwicki JE, Smith GR, Reitz AB, Baker BJ, Dickey CA. Synthesis, stereochemical analysis, and derivatization of myricanol provide new probes that promote autophagic tau clearance. ACS Chem Biol 2015; 10:1099-109. [PMID: 25588114 DOI: 10.1021/cb501013w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We previously discovered that one specific scalemic preparation of myricanol (1), a constituent of Myrica cerifera (bayberry/southern wax myrtle) root bark, could lower the levels of the microtubule-associated protein tau (MAPT). The significance is that tau accumulates in a number of neurodegenerative diseases, the most common being Alzheimer's disease (AD). Herein, a new synthetic route to prepare myricanol using a suitable boronic acid pinacol ester intermediate is reported. An X-ray crystal structure of the isolated myricanol (1) was obtained and showed a co-crystal consisting of (+)-aR,11S-myricanol (2) and (-)-aS,11R-myricanol (3) coformers. Surprisingly, 3, obtained from chiral separation from 1, reduced tau levels in both cultured cells and ex vivo brain slices from a mouse model of tauopathy at reasonable mid-to-low micromolar potency, whereas 2 did not. SILAC proteomics and cell assays revealed that 3 promoted tau degradation through an autophagic mechanism, which was in contrast to that of other tau-lowering compounds previously identified by our group. During the course of structure-activity relationship (SAR) development, we prepared compound 13 by acid-catalyzed dehydration of 1. 13 had undergone an unexpected structural rearrangement through the isomyricanol substitution pattern (e.g., 16), as verified by X-ray structural analysis. Compound 13 displayed robust tau-lowering activity, and, importantly, its enantiomers reduced tau levels similarly. Therefore, the semisynthetic analogue 13 provides a foundation for further development as a tau-lowering agent without its SAR being based on chirality.
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Affiliation(s)
- Mackenzie D. Martin
- Department
of Molecular Medicine and Alzheimer’s Institute, University of South Florida, Tampa, Florida 33613, United States
| | - Laurent Calcul
- Department
of Chemistry and Center for Drug Discovery and Innovation, University of South Florida, Tampa, Florida 33620, United States
| | - Courtney Smith
- Department
of Chemistry and Center for Drug Discovery and Innovation, University of South Florida, Tampa, Florida 33620, United States
| | - Umesh K. Jinwal
- Department
of Molecular Medicine and Alzheimer’s Institute, University of South Florida, Tampa, Florida 33613, United States
| | - Sarah N. Fontaine
- Department
of Molecular Medicine and Alzheimer’s Institute, University of South Florida, Tampa, Florida 33613, United States
| | - April Darling
- Department
of Molecular Medicine and Alzheimer’s Institute, University of South Florida, Tampa, Florida 33613, United States
| | - Kent Seeley
- Department
of Chemistry and Center for Drug Discovery and Innovation, University of South Florida, Tampa, Florida 33620, United States
| | - Lukasz Wojtas
- Department
of Chemistry and Center for Drug Discovery and Innovation, University of South Florida, Tampa, Florida 33620, United States
| | - Malathi Narayan
- Department
of Molecular Medicine and Alzheimer’s Institute, University of South Florida, Tampa, Florida 33613, United States
| | - Jason E. Gestwicki
- Department
of Pharmaceutical Chemistry, University of California, San Francisco, San
Francisco, California 94158, United States
| | - Garry R. Smith
- ALS Biopharma, LLC, 3805
Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Allen B. Reitz
- ALS Biopharma, LLC, 3805
Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Bill J. Baker
- Department
of Chemistry and Center for Drug Discovery and Innovation, University of South Florida, Tampa, Florida 33620, United States
| | - Chad A. Dickey
- Department
of Molecular Medicine and Alzheimer’s Institute, University of South Florida, Tampa, Florida 33613, United States
- Department
of Chemistry and Center for Drug Discovery and Innovation, University of South Florida, Tampa, Florida 33620, United States
- James A. Haley Veteran’s Hospital, 13000 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
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6
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Pickhardt M, Neumann T, Schwizer D, Callaway K, Vendruscolo M, Schenk D, St George-Hyslop P, Mandelkow EM, Dobson CM, McConlogue L, Mandelkow E, Tóth G. Identification of Small Molecule Inhibitors of Tau Aggregation by Targeting Monomeric Tau As a Potential Therapeutic Approach for Tauopathies. Curr Alzheimer Res 2015; 12:814-28. [PMID: 26510979 PMCID: PMC4976804 DOI: 10.2174/156720501209151019104951] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 06/13/2015] [Accepted: 06/26/2015] [Indexed: 12/15/2022]
Abstract
A potential strategy to alleviate the aggregation of intrinsically disordered proteins (IDPs) is to maintain the native functional state of the protein by small molecule binding. However, the targeting of the native state of IDPs by small molecules has been challenging due to their heterogeneous conformational ensembles. To tackle this challenge, we applied a high-throughput chemical microarray surface plasmon resonance imaging screen to detect the binding between small molecules and monomeric full-length Tau, a protein linked with the onset of a range of Tauopathies. The screen identified a novel set of drug-like fragment and lead-like compounds that bound to Tau. We verified that the majority of these hit compounds reduced the aggregation of different Tau constructs in vitro and in N2a cells. These results demonstrate that Tau is a viable receptor of drug-like small molecules. The drug discovery approach that we present can be applied to other IDPs linked to other misfolding diseases such as Alzheimer's and Parkinson's diseases.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Eckhard Mandelkow
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
| | - Gergely Tóth
- Department of Clinical Neuroscienes, Wolfson Brain Imaging Center, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 0QQ, United Kingdom.
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7
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Antimisiaris S, Mourtas S, Markoutsa E, Skouras A, Papadia K. Nanoparticles for Diagnosis and/or Treatment of Alzheimer's Disease. Adv Healthc Mater 2014. [DOI: 10.1002/9781118774205.ch4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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8
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Schafer KN, Cisek K, Huseby CJ, Chang E, Kuret J. Structural determinants of Tau aggregation inhibitor potency. J Biol Chem 2013; 288:32599-32611. [PMID: 24072703 DOI: 10.1074/jbc.m113.503474] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Small-molecule Tau aggregation inhibitors are under investigation as potential therapeutic agents against Alzheimer disease. Many such inhibitors have been identified in vitro, but their potency-driving features, and their molecular targets in the Tau aggregation pathway, have resisted identification. Previously we proposed ligand polarizability, a measure of electron delocalization, as a candidate descriptor of inhibitor potency. Here we tested this hypothesis by correlating the ground state polarizabilities of cyanine, phenothiazine, and arylmethine derivatives calculated using ab initio quantum methods with inhibitory potency values determined in the presence of octadecyl sulfate inducer under reducing conditions. A series of rhodanine analogs was analyzed as well using potency values disclosed in the literature. Results showed that polarizability and inhibitory potency directly correlated within all four series. To identify putative binding targets, representative members of the four chemotypes were added to aggregation reactions, where they were found to stabilize soluble, but SDS-resistant Tau species at the expense of filamentous aggregates. Using SDS resistance as a secondary assay, and a library of Tau deletion and missense mutants as targets, interaction with cyanine was localized to the microtubule binding repeat region. Moreover, the SDS-resistant phenotype was completely dependent on the presence of octadecyl sulfate inducer, but not intact PHF6/PH6* hexapeptide motifs, indicating that cyanine interacted with a species in the aggregation pathway prior to nucleus formation. Together the data suggest that flat, highly polarizable ligands inhibit Tau aggregation by interacting with folded species in the aggregation pathway and driving their assembly into soluble but highly stable Tau oligomers.
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Affiliation(s)
- Kelsey N Schafer
- From the Department of Molecular and Cellular Biochemistry, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Katryna Cisek
- From the Department of Molecular and Cellular Biochemistry, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Carol J Huseby
- From the Department of Molecular and Cellular Biochemistry, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Edward Chang
- From the Department of Molecular and Cellular Biochemistry, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Jeff Kuret
- From the Department of Molecular and Cellular Biochemistry, College of Medicine, The Ohio State University, Columbus, Ohio 43210.
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9
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Potential synergy between tau aggregation inhibitors and tau chaperone modulators. ALZHEIMERS RESEARCH & THERAPY 2013; 5:41. [PMID: 24041111 PMCID: PMC3979086 DOI: 10.1186/alzrt207] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tau is a soluble, microtubule-associated protein known to aberrantly form
amyloid-positive aggregates. This pathology is characteristic for more than 15
neuropathies, the most common of which is Alzheimer’s disease. Finding
therapeutics to reverse or remove this non-native tau state is of great
interest; however, at this time only one drug is entering phase III clinical
trials for treating tauopathies. Generally, tau manipulation by therapeutics can
either directly or indirectly alter tau aggregation and stability. Drugs that
bind and change the conformation of tau itself are largely classified as
aggregation inhibitors, while drugs that alter the activity of a tau-effector
protein fall into several categories, such as kinase inhibitors, microtubule
stabilizers, or chaperone modulators. Chaperone inhibitors that have proven
effective in tau models include heat shock protein 90 inhibitors, heat shock
protein 70 inhibitors and activators, as well as inducers of heat shock
proteins. While many of these compounds can alter tau levels and/or aggregation
states, it is possible that combining these approaches may produce the most
optimal outcome. However, because many of these compounds have multiple
off-target effects or poor blood–brain barrier permeability, the
development of this synergistic therapeutic strategy presents significant
challenges. This review will summarize many of the drugs that have been
identified to alter tau biology, with special focus on therapeutics that prevent
tau aggregation and regulate chaperone-mediated clearance of tau.
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10
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Ng OTW, Wong Y, Chan HM, Cheng J, Qi X, Chan WH, Yung KKL, Li HW. N-Acetyl-l-cysteine capped quantum dots offer neuronal cell protection by inhibiting beta (1-40) amyloid fibrillation. Biomater Sci 2013; 1:577-580. [PMID: 32481833 DOI: 10.1039/c3bm60029g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This is the first work that revealed the neuro-protective effect of functionalized quantum dots against the cytotoxicity induced by beta-amyloid peptides. This study gives insight into the future treatment of Alzheimer's disease. It opens many avenues for the development of the next generation nanotechnology for biomedical and therapeutic applications.
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Affiliation(s)
- Olivia T W Ng
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P. R. China.
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11
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Messing L, Decker JM, Joseph M, Mandelkow E, Mandelkow EM. Cascade of tau toxicity in inducible hippocampal brain slices and prevention by aggregation inhibitors. Neurobiol Aging 2012; 34:1343-1354. [PMID: 23158765 DOI: 10.1016/j.neurobiolaging.2012.10.024] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 09/10/2012] [Accepted: 10/23/2012] [Indexed: 11/18/2022]
Abstract
Mislocalization and aggregation of the axonal protein tau are hallmarks of Alzheimer's disease and other tauopathies. Here, we studied the relationship between tau aggregation, loss of spines and neurons, and reversibility by aggregation inhibitors. To this end we established an in vitro model of tauopathy based on regulatable transgenic hippocampal organotypic slice cultures prepared from mice expressing proaggregant Tau repeat domain with mutation ΔK280 (Tau(RD)ΔK). Transgene expression was monitored by a bioluminescence reporter assay. We observed abnormal tau phosphorylation and mislocalization of exogenous and endogenous tau into the somatodendritic compartment. This was paralleled by a reduction of dendritic spines, altered dendritic spine morphology, dysregulation of Ca(++) dynamics and elevated activation of microglia. Neurotoxicity was mediated by Caspase-3 activation and correlated with the expression level of proaggregant Tau(RD)ΔK. Finally, tau aggregates appeared in areas CA1 and CA3 after three weeks in vitro. Neurodegeneration was relieved by aggregation inhibitors or by switching off transgene expression. Thus the slice culture model is suitable for monitoring the development of tauopathy and the therapeutic benefit of antiaggregation drugs.
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Affiliation(s)
- Lars Messing
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Jochen Martin Decker
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Maria Joseph
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Eckhard Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
- CAESAR Research Center, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
- Max-Planck-Institute for Neurological Research (Cologne), Hamburg Outstation, c/o DESY, Notkestrasse 85, 22607 Hamburg
| | - Eva-Maria Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
- CAESAR Research Center, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
- Max-Planck-Institute for Neurological Research (Cologne), Hamburg Outstation, c/o DESY, Notkestrasse 85, 22607 Hamburg
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12
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Abstract
The ability to inhibit unwanted actions is a heritable executive function that may confer risk to disorders such as attention deficit hyperactivity disorder (ADHD). Converging evidence from pharmacology and cognitive neuroscience suggests that response inhibition is instantiated within frontostriatal circuits of the brain with patterns of activity that are modulated by the catecholamines dopamine and noradrenaline. A total of 405 healthy adult participants performed the stop-signal task, a paradigmatic measure of response inhibition that yields an index of the latency of inhibition, termed the stop-signal reaction time (SSRT). Using this phenotype, we tested for genetic association, performing high-density single-nucleotide polymorphism mapping across the full range of autosomal catecholamine genes. Fifty participants also underwent functional magnetic resonance imaging to establish the impact of associated alleles on brain and behaviour. Allelic variation in polymorphisms of the dopamine transporter gene (SLC6A3: rs37020; rs460000) predicted individual differences in SSRT, after corrections for multiple comparisons. Furthermore, activity in frontal regions (anterior frontal, superior frontal and superior medial gyri) and caudate varied additively with the T-allele of rs37020. The influence of genetic variation in SLC6A3 on the development of frontostriatal inhibition networks may represent a key risk mechanism for disorders of behavioural inhibition.
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13
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Abstract
INTRODUCTION: Tauopathies, including Alzheimer's disease (AD) and some frontotemporal dementias, are neurodegenerative diseases characterised by pathological lesions comprised of tau protein. There is currently a significant and urgent unmet need for disease-modifying therapies for these conditions and recently attention has turned to tau as a potential target for intervention. AREAS COVERED: Increasing evidence has highlighted pathways associated with tau-mediated neurodegeneration as important targets for drug development. Here, the authors review recently published papers in this area and summarise the genetic and pharmacological approaches that have shown efficacy in reducing tau-associated neurodegeneration. These include the use of agents to prevent abnormal tau processing and increase tau clearance, therapies targeting the immune system, and the manipulation of tau pre-mRNA to modify tau isoform expression. EXPERT OPINION: Several small molecule tau-based treatments are currently being assessed in clinical trials, the outcomes of which are eagerly awaited. Current evidence suggests that therapies targeting tau are likely, at least in part, to form the basis of an effective and safe treatment for Alzheimer's disease and related neurodegenerative disorders in which tau deposition is evident.
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Affiliation(s)
- Wendy Noble
- MRC Centre for Neurodegeneration Research, Department of Neuroscience (P037), King’s College London, Institute of Psychiatry, De Crespigny Park, London, SE5 8AF, UK. Tel: +44 20 7848 0578.
| | - Amy M. Pooler
- MRC Centre for Neurodegeneration Research, Department of Neuroscience (P037), King’s College London, Institute of Psychiatry, De Crespigny Park, London, SE5 8AF, UK. Tel: +44 (0)20 7848 5375.
| | - Diane P. Hanger
- MRC Centre for Neurodegeneration Research, Department of Neuroscience (P037), King’s College London, Institute of Psychiatry, De Crespigny Park, London, SE5 8AF, UK. Tel: +44 (0)20 7848 0041.
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14
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Schafer KN, Murale DP, Kim K, Cisek K, Kuret J, Churchill DG. Structure-activity relationship of cyclic thiacarbocyanine tau aggregation inhibitors. Bioorg Med Chem Lett 2011; 21:3273-6. [PMID: 21549596 DOI: 10.1016/j.bmcl.2011.04.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2010] [Revised: 04/04/2011] [Accepted: 04/08/2011] [Indexed: 11/19/2022]
Abstract
Macrocyclic bis-thiacarbocyanines are efficacious inhibitors of tau protein aggregation. To extend the structure-activity relationship of this inhibitor class, N,N'-alkylene bis-thiacarbocyanines linked by chains of three to eight methylene carbons were synthesized and examined for inhibitory activity against recombinant human tau aggregation in vitro. At 10 micromolar concentration, inhibitory activity varied with linker length, with four methylene units being most efficacious. On the basis of absorbance spectroscopy measurements, linker length also affected compound folding and aggregation propensity, with a linker length of four methylene units being optimal for preserving open monomer conformation. These data suggest that inhibitory potency can be optimized through control of linker length, and that a contributory mechanism involves modulation of compound folding and aggregation.
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Affiliation(s)
- Kelsey N Schafer
- Center for Molecular Neurobiology, Department of Molecular and Cellular Biochemistry, The Ohio State University College of Medicine, 1060 Carmack Rd, Columbus, OH 43210, USA
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15
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Tau-induced defects in synaptic plasticity, learning, and memory are reversible in transgenic mice after switching off the toxic Tau mutant. J Neurosci 2011; 31:2511-25. [PMID: 21325519 DOI: 10.1523/jneurosci.5245-10.2011] [Citation(s) in RCA: 226] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
This report describes the behavioral and electrophysiological analysis of regulatable transgenic mice expressing mutant repeat domains of human Tau (Tau(RD)). Mice were generated to express Tau(RD) in two forms, differing in their propensity for β-structure and thus in their tendency for aggregation ("pro-aggregant" or "anti-aggregant") (Mocanu et al., 2008). Only pro-aggregant mice show pronounced changes typical for Tau pathology in Alzheimer's disease (aggregation, missorting, hyperphosphorylation, synaptic and neuronal loss), indicating that the β-propensity and hence the ability to aggregate is a key factor in the disease. We now tested the mice with regard to neuromotor parameters, behavior, learning and memory, and synaptic plasticity and correlated this with histological and biochemical parameters in different stages of switching Tau(RD) on or off. The mice are normal in neuromotor tests. However, pro-aggregant Tau(RD) mice are strongly impaired in memory and show pronounced loss of long-term potentiation (LTP), suggesting that Tau aggregation specifically perturbs these brain functions. Remarkably, when the expression of human pro-aggregant Tau(RD) is switched on for ∼ 10 months and off for ∼ 4 months, memory and LTP recover, whereas aggregates decrease moderately and change their composition from mixed human plus mouse Tau to mouse Tau only. Neuronal loss persists, but synapses are partially rescued. This argues that continuous presence of amyloidogenic pro-aggregant Tau(RD) constitutes the main toxic insult for memory and LTP, rather than the aggregates as such.
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Neuroactive Multifunctional Tacrine Congeners with Cholinesterase, Anti-Amyloid Aggregation and Neuroprotective Properties. Pharmaceuticals (Basel) 2011. [PMCID: PMC4053961 DOI: 10.3390/ph4020382] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Ballatore C, Brunden KR, Trojanowski JQ, Lee VMY, Smith AB, Huryn DM. Modulation of protein-protein interactions as a therapeutic strategy for the treatment of neurodegenerative tauopathies. Curr Top Med Chem 2011; 11:317-30. [PMID: 21320060 PMCID: PMC3069499 DOI: 10.2174/156802611794072605] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Accepted: 04/16/2010] [Indexed: 12/26/2022]
Abstract
The recognition that malfunction of the microtubule (MT) associated protein tau is likely to play a defining role in the onset and/or progression of a number of neurodegenerative diseases, including Alzheimer's disease, has resulted in the initiation of drug discovery programs that target this protein. Tau is an endogenous MT-stabilizing agent that is highly expressed in the axons of neurons. The MT-stabilizing function of tau is essential for the axonal transport of proteins, neurotransmitters and other cellular constituents. Under pathological conditions, tau misfolding and aggregation results in axonal transport deficits that appear to have deleterious consequences for the affected neurons, leading to synapse dysfunction and, ultimately, neuronal loss. This review focuses on both progress and unresolved issues surrounding the development of novel therapeutics for the treatment of neurodegenerative tauopathies, which are based on (A) MT-stabilizing agents to compensate for the loss of normal tau function, and (B) small molecule inhibitors of tau aggregation.
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Affiliation(s)
- C Ballatore
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, 231 South 34th St., Philadelphia, PA 19104-6323, USA.
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Bartolini M, Andrisano V. Strategies for the Inhibition of Protein Aggregation in Human Diseases. Chembiochem 2010; 11:1018-35. [DOI: 10.1002/cbic.200900666] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Bulic B, Pickhardt M, Mandelkow EM, Mandelkow E. Tau protein and tau aggregation inhibitors. Neuropharmacology 2010; 59:276-89. [PMID: 20149808 DOI: 10.1016/j.neuropharm.2010.01.016] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 01/20/2010] [Accepted: 01/26/2010] [Indexed: 12/13/2022]
Abstract
Alzheimer disease is characterized by pathological aggregation of two proteins, tau and Abeta-amyloid, both of which are considered to be toxic to neurons. In this review we summarize recent advances on small molecule inhibitors of protein aggregation with emphasis on tau, with activities mediated by the direct interference of self-assembly. The inhibitors can be clustered in several compound classes according to their chemical structure, with subsequent description of the structure-activity relationships, showing that hydrophobic interactions are prevailing. The description is extended to the pharmacological profile of the compounds in order to evaluate their drug-likeness, with special attention to toxicity and bioavailability. The collected data indicate that following the improvements of the in vitro inhibitory potencies, the consideration of the in vivo pharmacokinetics is an absolute prerequisite for the development of compounds suitable for a transfer from bench to bedside.
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Affiliation(s)
- Bruno Bulic
- Center for Advanced European Studies and Research, Bonn, Germany.
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Meraz-Ríos MA, Lira-De León KI, Campos-Peña V, De Anda-Hernández MA, Mena-López R. Tau oligomers and aggregation in Alzheimer's disease. J Neurochem 2009; 112:1353-67. [PMID: 19943854 DOI: 10.1111/j.1471-4159.2009.06511.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We are analyzing the physiological function of Tau protein and its abnormal pathological behavior when this protein is self-assemble into pathological filaments. These aggregates of Tau protein are the main components in many diseases such as Alzheimer's disease (AD). Recent studies suggest that Tau acquires complex oligomeric conformations which may be toxic. In this review, we emphasized the possible phenomena implicated in the formation of these oligomers. Studies with chemical inductors indicates that the microtubule-binding domain is the most important region involved in Tau aggregation and showed the requirement of a pre-arrange Tau in abnormal conformation to promote self-assembly. Transgenic animal models and AD neuropathology studies showed that post-translational modifications are also implicated in Tau aggregation and neural cell death during AD development. Therefore, we analyzed some events that could be present during Tau aggregation. Finally, we included a brief discussion of the possible relation between glucose metabolism dysfunction in AD, and data of Tau aggregation by using aggregation inhibitors. In conclusion, the process Tau aggregation deserves further investigations to design possible therapeutic targets to inhibit the toxicity of these aggregates and it is possible that could be extended to other diseases with similar etiology.
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Affiliation(s)
- Marco A Meraz-Ríos
- Department of Molecular Biomedicine, Center of Research and Advanced Studies CINVESTAV-IPN, México DF, Mexico.
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