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Das V, Miller JH, Alladi CG, Annadurai N, De Sanctis JB, Hrubá L, Hajdúch M. Antineoplastics for treating Alzheimer's disease and dementia: Evidence from preclinical and observational studies. Med Res Rev 2024. [PMID: 38530106 DOI: 10.1002/med.22033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 02/15/2024] [Accepted: 03/04/2024] [Indexed: 03/27/2024]
Abstract
As the world population ages, there will be an increasing need for effective therapies for aging-associated neurodegenerative disorders, which remain untreatable. Dementia due to Alzheimer's disease (AD) is one of the leading neurological diseases in the aging population. Current therapeutic approaches to treat this disorder are solely symptomatic, making the need for new molecular entities acting on the causes of the disease extremely urgent. One of the potential solutions is to use compounds that are already in the market. The structures have known pharmacokinetics, pharmacodynamics, toxicity profiles, and patient data available in several countries. Several drugs have been used successfully to treat diseases different from their original purposes, such as autoimmunity and peripheral inflammation. Herein, we divulge the repurposing of drugs in the area of neurodegenerative diseases, focusing on the therapeutic potential of antineoplastics to treat dementia due to AD and dementia. We briefly touch upon the shared pathological mechanism between AD and cancer and drug repurposing strategies, with a focus on artificial intelligence. Next, we bring out the current status of research on the development of drugs, provide supporting evidence from retrospective, clinical, and preclinical studies on antineoplastic use, and bring in new areas, such as repurposing drugs for the prion-like spreading of pathologies in treating AD.
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Affiliation(s)
- Viswanath Das
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
- Czech Advanced Technologies and Research Institute (CATRIN), Institute of Molecular and Translational Medicine, Palacký University Olomouc, Olomouc, Czech Republic
| | - John H Miller
- School of Biological Sciences and Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
| | - Charanraj Goud Alladi
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
| | - Narendran Annadurai
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
| | - Juan Bautista De Sanctis
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
- Czech Advanced Technologies and Research Institute (CATRIN), Institute of Molecular and Translational Medicine, Palacký University Olomouc, Olomouc, Czech Republic
| | - Lenka Hrubá
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
- Czech Advanced Technologies and Research Institute (CATRIN), Institute of Molecular and Translational Medicine, Palacký University Olomouc, Olomouc, Czech Republic
| | - Marián Hajdúch
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
- Czech Advanced Technologies and Research Institute (CATRIN), Institute of Molecular and Translational Medicine, Palacký University Olomouc, Olomouc, Czech Republic
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Padmanabhan P, Kneynsberg A, Cruz E, Briner A, Götz J. Single-molecule imaging of Tau reveals how phosphorylation affects its movement and confinement in living cells. Mol Brain 2024; 17:7. [PMID: 38347594 PMCID: PMC10863257 DOI: 10.1186/s13041-024-01078-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 01/22/2024] [Indexed: 02/15/2024] Open
Abstract
Tau is a microtubule-associated protein that is regulated by post-translational modifications. The most studied of these modifications is phosphorylation, which affects Tau's aggregation and loss- and gain-of-functions, including the interaction with microtubules, in Alzheimer's disease and primary tauopathies. However, little is known about how Tau's phosphorylation state affects its dynamics and organisation at the single-molecule level. Here, using quantitative single-molecule localisation microscopy, we examined how mimicking or abrogating phosphorylation at 14 disease-associated serine and threonine residues through mutagenesis influences the behaviour of Tau in live Neuro-2a cells. We observed that both pseudohyperphosphorylated Tau (TauE14) and phosphorylation-deficient Tau (TauA14) exhibit a heterogeneous mobility pattern near the plasma membrane. Notably, we found that the mobility of TauE14 molecules was higher than wild-type Tau molecules, while TauA14 molecules displayed lower mobility. Moreover, TauA14 was organised in a filament-like structure resembling cytoskeletal filaments, within which TauA14 exhibited spatial and kinetic heterogeneity. Our study provides a direct visualisation of how the phosphorylation state of Tau affects its spatial and temporal organisation, presumably reflecting the phosphorylation-dependent changes in the interactions between Tau and its partners. We suggest that alterations in Tau dynamics resulting from aberrant changes in phosphorylation could be a critical step in its pathological dysregulation.
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Affiliation(s)
- Pranesh Padmanabhan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia.
| | - Andrew Kneynsberg
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Esteban Cruz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Adam Briner
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia.
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Siew JJ, Chen HM, Chiu FL, Lee CW, Chang YM, Chen HL, Nguyen TNA, Liao HT, Liu M, Hagar HT, Sun YC, Lai HL, Kuo MH, Blum D, Buée L, Jin LW, Chen SY, Ko TM, Huang JR, Kuo HC, Liu FT, Chern Y. Galectin-3 aggravates microglial activation and tau transmission in tauopathy. J Clin Invest 2024; 134:e165523. [PMID: 37988169 PMCID: PMC10786694 DOI: 10.1172/jci165523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/16/2023] [Indexed: 11/23/2023] Open
Abstract
Alzheimer's disease is characterized by the accumulation of amyloid-β plaques, aggregation of hyperphosphorylated tau (pTau), and microglia activation. Galectin-3 (Gal3) is a β-galactoside-binding protein that has been implicated in amyloid pathology. Its role in tauopathy remains enigmatic. Here, we showed that Gal3 was upregulated in the microglia of humans and mice with tauopathy. pTau triggered the release of Gal3 from human induced pluripotent stem cell-derived microglia in both its free and extracellular vesicular-associated (EV-associated) forms. Both forms of Gal3 increased the accumulation of pathogenic tau in recipient cells. Binding of Gal3 to pTau greatly enhanced tau fibrillation. Besides Gal3, pTau was sorted into EVs for transmission. Moreover, pTau markedly enhanced the number of EVs released by iMGL in a Gal3-dependent manner, suggesting a role of Gal3 in biogenesis of EVs. Single-cell RNA-Seq analysis of the hippocampus of a mouse model of tauopathy (THY-Tau22) revealed a group of pathogenic tau-evoked, Gal3-associated microglia with altered cellular machineries implicated in neurodegeneration, including enhanced immune and inflammatory responses. Genetic removal of Gal3 in THY-Tau22 mice suppressed microglia activation, reduced the level of pTau and synaptic loss in neurons, and rescued memory impairment. Collectively, Gal3 is a potential therapeutic target for tauopathy.
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Affiliation(s)
| | | | - Feng-Lan Chiu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | | | | | | | | | | | - Mengyu Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Hsiao-Tien Hagar
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Yung-Chen Sun
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | | | - Min-Hao Kuo
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - David Blum
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
- Alzheimer & Tauopathies, LabEx DISTALZ, LiCEND, Lille, France
| | - Luc Buée
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
- Alzheimer & Tauopathies, LabEx DISTALZ, LiCEND, Lille, France
| | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine, University of California Davis, Sacramento, California, USA
| | | | - Tai-Ming Ko
- Institute of Biomedical Sciences
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Jie-Rong Huang
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Hung-Chih Kuo
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
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Abstract
Deposits of the microtubule-associated protein Tau (MAPT) serve as a hallmark of neurodegenerative diseases known as tauopathies. Numerous studies have demonstrated that in diseases such as Alzheimer's disease (AD), Tau undergoes extensive remodeling. The attachment of post-translational modifications distributed throughout the entire sequence of the protein correlates with clinical presentation. A systematic examination of these protein alterations can shed light on their roles in both healthy and diseased states. However, the ability to access these modifications in the entire protein chain is limited as Tau can only be produced recombinantly or through semisynthesis. In this article, we describe the first chemical synthesis of the longest 2N4R isoform of Tau, consisting of 441 amino acids. The 2N4R Tau was divided into 3 major segments and a total of 11 fragments, all of which were prepared via solid-phase peptide synthesis. The successful chemical strategy has relied on the strategic use of two cysteine sites (C291 and C322) for the native chemical ligations (NCLs). This was combined with modern preparative protein chemistries, such as mercaptothreonine ligation (T205), diselenide-selenoester ligation (D358), and mutations of mercaptoamino acids into native residues via homogeneous radical desulfurization (A40, A77, A119, A157, A246, and A390). The successful completion of the synthesis has established a robust and scalable route to the native protein in multimilligram quantities and high purity. In broader terms, the presented strategy can be applied to the preparation of other shorter isoforms of Tau as well as to introduce all post-translational modifications that are characteristic of tauopathies such as AD.
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Affiliation(s)
- Wyatt C Powell
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Ruiheng Jing
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Maciej A Walczak
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
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Vogel JW, Corriveau-Lecavalier N, Franzmeier N, Pereira JB, Brown JA, Maass A, Botha H, Seeley WW, Bassett DS, Jones DT, Ewers M. Connectome-based modelling of neurodegenerative diseases: towards precision medicine and mechanistic insight. Nat Rev Neurosci 2023; 24:620-639. [PMID: 37620599 DOI: 10.1038/s41583-023-00731-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2023] [Indexed: 08/26/2023]
Abstract
Neurodegenerative diseases are the most common cause of dementia. Although their underlying molecular pathologies have been identified, there is substantial heterogeneity in the patterns of progressive brain alterations across and within these diseases. Recent advances in neuroimaging methods have revealed that pathological proteins accumulate along specific macroscale brain networks, implicating the network architecture of the brain in the system-level pathophysiology of neurodegenerative diseases. However, the extent to which 'network-based neurodegeneration' applies across the wide range of neurodegenerative disorders remains unclear. Here, we discuss the state-of-the-art of neuroimaging-based connectomics for the mapping and prediction of neurodegenerative processes. We review findings supporting brain networks as passive conduits through which pathological proteins spread. As an alternative view, we also discuss complementary work suggesting that network alterations actively modulate the spreading of pathological proteins between connected brain regions. We conclude this Perspective by proposing an integrative framework in which connectome-based models can be advanced along three dimensions of innovation: incorporating parameters that modulate propagation behaviour on the basis of measurable biological features; building patient-tailored models that use individual-level information and allowing model parameters to interact dynamically over time. We discuss promises and pitfalls of these strategies for improving disease insights and moving towards precision medicine.
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Affiliation(s)
- Jacob W Vogel
- Department of Clinical Sciences, SciLifeLab, Lund University, Lund, Sweden.
| | - Nick Corriveau-Lecavalier
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA
| | - Nicolai Franzmeier
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Acadamy, University of Gothenburg, Mölndal and Gothenburg, Sweden
| | - Joana B Pereira
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
- Neuro Division, Department of Clinical Neurosciences, Karolinska Institute, Stockholm, Sweden
| | - Jesse A Brown
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, USA
| | - Anne Maass
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Hugo Botha
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - William W Seeley
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, USA
- Department of Pathology, University of California, San Francisco, CA, USA
| | - Dani S Bassett
- Departments of Bioengineering, Electrical and Systems Engineering, Physics and Astronomy, Neurology and Psychiatry, University of Pennsylvania, Philadelphia, PA, USA
- Santa Fe Institute, Santa Fe, NM, USA
| | - David T Jones
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Michael Ewers
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany.
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Hromadkova L, Kim C, Haldiman T, Peng L, Zhu X, Cohen M, de Silva R, Safar JG. Evolving prion-like tau conformers differentially alter postsynaptic proteins in neurons inoculated with distinct isolates of Alzheimer's disease tau. Cell Biosci 2023; 13:174. [PMID: 37723591 PMCID: PMC10507869 DOI: 10.1186/s13578-023-01133-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 09/12/2023] [Indexed: 09/20/2023] Open
Abstract
OBJECTIVES Although accumulation of misfolded tau species has been shown to predict cognitive decline in patients with Alzheimer's disease (AD) and other tauopathies but with the remarkable diversity of clinical manifestations, neuropathology profiles, and time courses of disease progression remaining unexplained by current genetic data. We considered the diversity of misfolded tau conformers present in individual AD cases as an underlying driver of the phenotypic variations of AD and progressive loss of synapses. METHODS To model the mechanism of tau propagation and synaptic toxicity of distinct tau conformers, we inoculated wild-type primary mouse neurons with structurally characterized Sarkosyl-insoluble tau isolates from the frontal cortex of six AD cases and monitored the impact for fourteen days. We analyzed the accumulation rate, tau isoform ratio, and conformational characteristics of de novo-induced tau aggregates with conformationally sensitive immunoassays, and the dynamics of synapse formation, maintenance, and their loss using a panel of pre-and post-synaptic markers. RESULTS At the same concentrations of tau, the different AD tau isolates induced accumulation of misfolded predominantly 4-repeat tau aggregates at different rates in mature neurons, and demonstrated distinct conformational characteristics corresponding to the original AD brain tau. The time-course of the formation of misfolded tau aggregates and colocalization correlated with significant loss of synapses in tau-inoculated cell cultures and the reduction of synaptic connections implicated the disruption of postsynaptic compartment as an early event. CONCLUSIONS The data obtained with mature neurons expressing physiological levels and adult isoforms of tau protein demonstrate markedly different time courses of endogenous tau misfolding and differential patterns of post-synaptic alterations. These and previous biophysical data argue for an ensemble of various misfolded tau aggregates in individual AD brains and template propagation of their homologous conformations in neurons with different rates and primarily postsynaptic interactors. Modeling tau aggregation in mature differentiated neurons provides a platform for investigating divergent molecular mechanisms of tau strain propagation and for identifying common structural features of misfolded tau and critical interactors for new therapeutic targets and approaches in AD.
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Affiliation(s)
- Lenka Hromadkova
- Departments of Pathology, Case Western Reserve University School of Medicine, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Chae Kim
- Departments of Pathology, Case Western Reserve University School of Medicine, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Tracy Haldiman
- Departments of Pathology, Case Western Reserve University School of Medicine, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Lihua Peng
- Departments of Pathology, Case Western Reserve University School of Medicine, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
| | - Xiongwei Zhu
- Departments of Pathology, Case Western Reserve University School of Medicine, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
- Departments of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Mark Cohen
- Departments of Pathology, Case Western Reserve University School of Medicine, 2085 Adelbert Rd, Cleveland, OH, 44106, USA
- National Prion Disease Pathology Surveillance Center, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Rohan de Silva
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, WC1N 1PJ, UK
| | - Jiri G Safar
- Departments of Pathology, Case Western Reserve University School of Medicine, 2085 Adelbert Rd, Cleveland, OH, 44106, USA.
- Departments of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
- Departments of Neuroscience, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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Johansson B, Oasa S, Muntsant Soria A, Tiiman A, Söderberg L, Amandius E, Möller C, Lannfelt L, Terenius L, Giménez-Llort L, Vukojević V. The interwoven fibril-like structure of amyloid-beta plaques in mouse brain tissue visualized using super-resolution STED microscopy. Cell Biosci 2023; 13:142. [PMID: 37542303 PMCID: PMC10403925 DOI: 10.1186/s13578-023-01086-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/14/2023] [Indexed: 08/06/2023] Open
Abstract
BACKGROUND Standard neuropathologic analysis of Alzheimer's brain relies on traditional fluorescence microscopy, which suffers from limited spatial resolution due to light diffraction. As a result, it fails to reveal intricate details of amyloid plaques. While electron microscopy (EM) offers higher resolution, its extensive sample preparation, involving fixation, dehydration, embedding, and sectioning, can introduce artifacts and distortions in the complex brain tissue. Moreover, EM lacks molecular specificity and has limited field of view and imaging depth. RESULTS In our study, we employed super-resolution Stimulated Emission Depletion (STED) microscopy in conjunction with the anti-human APP recombinant antibody 1C3 fluorescently labelled with DyLightTM633 (1C3-DyLight633). This combination allowed us to visualize amyloidogenic aggregates in vitro and in brain sections from a 17-month-old 3×Tg-AD mouse with sub-diffraction limited spatial resolution. Remarkably, we achieved a spatial resolution of 29 nm in vitro and 62 nm in brain tissue sections, surpassing the capabilities of conventional confocal microscopy by 5-10 times. Consequently, we could discern individual fibrils within plaques, an achievement previously only possible with EM. CONCLUSIONS The utilization of STED microscopy represents a groundbreaking advancement in the field, enabling researchers to delve into the characterization of local mechanisms that underlie Amyloid (Aβ) deposition into plaques and their subsequent clearance. This unprecedented level of detail is especially crucial for comprehending the etiology of Alzheimer's disease and developing the next generation of anti-amyloid treatments. By facilitating the evaluation of drug candidates and non-pharmacological interventions aiming to reduce amyloid burden, STED microscopy emerges as an indispensable tool for driving scientific progress in Alzheimer's research.
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Affiliation(s)
- Björn Johansson
- Department of Clinical Neuroscience, Karolinska Institutet, SE-17176, Stockholm, Sweden
- Theme Aging, Karolinska University Hospital, Karolinska Institutet, SE-17176, Stockholm, Sweden
| | - Sho Oasa
- Department of Clinical Neuroscience, Karolinska Institutet, SE-17176, Stockholm, Sweden
| | - Aida Muntsant Soria
- Institut de Neurociències, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain
- Department of Psychiatry and Forensic Medicine, School of Medicine, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain
| | - Ann Tiiman
- Department of Clinical Neuroscience, Karolinska Institutet, SE-17176, Stockholm, Sweden
| | | | | | | | | | - Lars Terenius
- Department of Clinical Neuroscience, Karolinska Institutet, SE-17176, Stockholm, Sweden
| | - Lydia Giménez-Llort
- Institut de Neurociències, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain
- Department of Psychiatry and Forensic Medicine, School of Medicine, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain
| | - Vladana Vukojević
- Department of Clinical Neuroscience, Karolinska Institutet, SE-17176, Stockholm, Sweden.
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8
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Lopez DM, Maltby CJ, Warming H, Divecha N, Vargas-Caballero M, Coldwell MJ, Deinhardt K. A luminescence-based reporter to study tau secretion reveals overlapping mechanisms for the release of healthy and pathological tau. Front Neurosci 2023; 17:1196007. [PMID: 37342467 PMCID: PMC10277490 DOI: 10.3389/fnins.2023.1196007] [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: 03/29/2023] [Accepted: 05/17/2023] [Indexed: 06/23/2023] Open
Abstract
In Alzheimer's disease, tau pathology is thought to spread via a prion-like manner along connected neuronal networks. For this to occur, the usually cytosolic tau protein must be secreted via an unconventional mechanism prior to uptake into the connected neuron. While secretion of healthy and pathological tau has been documented, it remains under-investigated whether this occurs via overlapping or distinct processes. Here, we established a sensitive bioluminescence-based assay to assess mechanisms underlying the secretion of pseudohyperphosphorylated and wild-type tau in cultured murine hippocampal neurons. We found that under basal conditions, both wild-type and mutant tau are secreted, with mutant tau being more robustly secreted. Pharmacological stimulation of neuronal activity led to a modest increase of wild-type and mutant tau secretion, whereas inhibition of activity had no effect. Interestingly, inhibition of heparin sulfate proteoglycan (HSPG) biosynthesis drastically decreased secretion of both wild-type and mutant tau without affecting cell viability. This shows that native and pathological tau share release mechanisms; both activity-dependent and non-activity-dependent secretion of tau is facilitated by HSPGs.
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Jarrah R, Nathani KR, Bhandarkar S, Ezeudu CS, Nguyen RT, Amare A, Aljameey UA, Jarrah SI, Bhandarkar AR, Fiani B. Microfluidic 'brain-on chip' systems to supplement neurological practice: development, applications and considerations. Regen Med 2023; 18:413-423. [PMID: 37125510 DOI: 10.2217/rme-2022-0212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Among the greatest general challenges in bioengineering is to mimic human physiology. Advanced efforts in tissue engineering have led to sophisticated 'brain-on-chip' (BoC) microfluidic devices that can mimic structural and functional aspects of brain tissue. BoC may be used to understand the biochemical pathways of neurolgical pathologies and assess promising therapeutic agents for facilitating regenerative medicine. We evaluated the potential of microfluidic BoC devices in various neurological pathologies, such as Alzheimer's, glioblastoma, traumatic brain injury, stroke and epilepsy. We also discuss the principles, limitations and future considerations of BoC technology. Results suggest that BoC models can help understand complex neurological pathologies and augment drug testing efforts for regenerative applications. However, implementing organ-on-chip technology to clinical practice has some practical limitations that warrant greater attention to improve large-scale applicability. Nevertheless, they remain to be versatile and powerful tools that can broaden our understanding of pathophysiological and therapeutic uncertainties to neurological diseases.
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Affiliation(s)
- Ryan Jarrah
- Department of Neurosurgery, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Shaan Bhandarkar
- Department of Neuroscience, Yale University, New Haven, CT 06510, USA
| | - Chibuze S Ezeudu
- Texas A&M School of Medicine,Texas A&M University, Bryan, TX 77807, USA
| | - Ryan T Nguyen
- University of Hawaii John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA
| | - Abrham Amare
- Morehouse School of Medicine, Morehouse College, Atlanta, GA 30310, USA
| | - Usama A Aljameey
- Lincoln Memorial University DeBusk School of Osteopathic Medicine, Lincoln Memorial University, Knoxville, TN 37923, USA
| | - Sabrina I Jarrah
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Brian Fiani
- Department of Neurosurgery, Cornell Medical Center/New York Presbyterian, New York, NY 10065, USA
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Neuroprotective Action of Coumarin Derivatives through Activation of TRKB-CREB-BDNF Pathway and Reduction of Caspase Activity in Neuronal Cells Expressing Pro-Aggregated Tau Protein. Int J Mol Sci 2022; 23:ijms232112734. [PMID: 36361524 PMCID: PMC9654711 DOI: 10.3390/ijms232112734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/20/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022] Open
Abstract
Hyperphosphorylation and aggregation of the microtubule binding protein tau is a neuropathological hallmark of Alzheimer’s disease/tauopathies. Tau neurotoxicity provokes alterations in brain-derived neurotrophic factor (BDNF)/tropomycin receptor kinase B (TRKB)/cAMP-response-element binding protein (CREB) signaling to contribute to neurodegeneration. Compounds activating TRKB may therefore provide beneficial effects in tauopathies. LM-031, a coumarin derivative, has demonstrated the potential to improve BDNF signaling in neuronal cells expressing pro-aggregated ΔK280 tau mutant. In this study, we investigated if LM-031 analogous compounds provide neuroprotection effects through interaction with TRKB in SH-SY5Y cells expressing ΔK280 tauRD-DsRed folding reporter. All four LMDS compounds reduced tau aggregation and reactive oxygen species. Among them, LMDS-1 and -2 reduced caspase-1, caspase-6 and caspase-3 activities and promoted neurite outgrowth, and the effect was significantly reversed by knockdown of TRKB. Treatment of ERK inhibitor U0126 or PI3K inhibitor wortmannin decreased p-CREB, BDNF and BCL2 in these cells, implying that the neuroprotective effects of LMDS-1/2 are via activating TRKB downstream ERK, PI3K-AKT and CREB signaling. Furthermore, LMDS-1/2 demonstrated their ability to quench the intrinsic fluorescence of tryptophan residues within the extracellular domain of TRKB, thereby consolidating their interaction with TRKB. Our results suggest that LMDS-1/2 exert neuroprotection through activating TRKB signaling, and shed light on their potential application in therapeutics of Alzheimer’s disease/tauopathies.
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11
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Blaudin de Thé FX, Lassus B, Schaler AW, Fowler SL, Goulbourne CN, Jeggo R, Mannoury la Cour C, Millan MJ, Duff KE. P62 accumulates through neuroanatomical circuits in response to tauopathy propagation. Acta Neuropathol Commun 2021; 9:177. [PMID: 34727983 PMCID: PMC8561893 DOI: 10.1186/s40478-021-01280-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/17/2021] [Indexed: 12/26/2022] Open
Abstract
In Alzheimer's disease and related tauopathies, trans-synaptic transfer and accumulation of pathological tau from donor to recipient neurons is thought to contribute to disease progression, but the underlying mechanisms are poorly understood. Using complementary in vivo and in vitro models, we examined the relationship between these two processes and neuronal clearance. Accumulation of p62 (a marker of defective protein clearance) correlated with pathological tau accumulation in two mouse models of tauopathy spread; Entorhinal Cortex-tau (EC-Tau) mice where tau pathology progresses in time from EC to other brain regions, and PS19 mice injected with tau seeds. In both models and in several brain regions, p62 colocalized with human tau in a pathological conformation (MC1 antibody). In EC-Tau mice, p62 accumulated before overt tau pathology had developed and was associated with the presence of aggregation-competent tau seeds identified using a FRET-based assay. Furthermore, p62 accumulated in the cytoplasm of neurons in the dentate gyrus of EC-Tau mice prior to the appearance of MC1 positive tauopathy. However, MC1 positive tau was shown to be present at the synapse and to colocalize with p62 as shown by immuno electron microscopy. In vitro, p62 colocalized with tau inclusions in two primary cortical neuron models of tau pathology. In a three-chamber microfluidic device containing neurons overexpressing fluorescent tau, seeding of tau in the donor chamber led to tau pathology spread and p62 accumulation in both the donor and the recipient chamber. Overall, these data are in accordance with the hypothesis that the accumulation and trans-synaptic spread of pathological tau disrupts clearance mechanisms, preceding the appearance of obvious tau aggregation. A vicious cycle of tau accumulation and clearance deficit would be expected to feed-forward and exacerbate disease progression across neuronal circuits in human tauopathies.
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Affiliation(s)
- François-Xavier Blaudin de Thé
- Taub Institute for Research On Alzheimer’s Disease and the Aging Brain, 630 W 168th St, NY 10032 New York, USA
- Neuroscience and Immunoinflammation Therapeutic Area, Institut de Recherche Servier, 125 Chemin de Ronde, 78290 Croissy-sur-Seine, France
| | - Benjamin Lassus
- Taub Institute for Research On Alzheimer’s Disease and the Aging Brain, 630 W 168th St, NY 10032 New York, USA
- HiFiBiO Therapeutics Pépinière Paris Santé Cochin, 29 Rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Ari W. Schaler
- Taub Institute for Research On Alzheimer’s Disease and the Aging Brain, 630 W 168th St, NY 10032 New York, USA
- UCLA – Physiology Department, 10833 Le Conte Ave, CHS76200, CA 90095 Los Angeles, USA
| | - Stephanie L. Fowler
- Taub Institute for Research On Alzheimer’s Disease and the Aging Brain, 630 W 168th St, NY 10032 New York, USA
- UK Dementia Research Institute at UCL, University College London, 90 Gower St, W1T 7NF London, UK
| | - Chris N. Goulbourne
- Nathan Kline Institute: Center for Dementia Research, 140 Old Orangeburg Road, NY 10962 Orangeburg, USA
| | - Ross Jeggo
- Neuroscience and Immunoinflammation Therapeutic Area, Institut de Recherche Servier, 125 Chemin de Ronde, 78290 Croissy-sur-Seine, France
| | - Clotilde Mannoury la Cour
- Neuroscience and Immunoinflammation Therapeutic Area, Institut de Recherche Servier, 125 Chemin de Ronde, 78290 Croissy-sur-Seine, France
| | - Mark J. Millan
- Neuroscience and Immunoinflammation Therapeutic Area, Institut de Recherche Servier, 125 Chemin de Ronde, 78290 Croissy-sur-Seine, France
- Present Address: Institute of Neuroscience and Psychology, College of Medicine, Vet and Life Science, Glasgow University, Glasgow, G12 8QQ United Kingdom
| | - Karen E. Duff
- Taub Institute for Research On Alzheimer’s Disease and the Aging Brain, 630 W 168th St, NY 10032 New York, USA
- UK Dementia Research Institute at UCL, University College London, 90 Gower St, W1T 7NF London, UK
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12
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Zhang H, Cao Y, Ma L, Wei Y, Li H. Possible Mechanisms of Tau Spread and Toxicity in Alzheimer's Disease. Front Cell Dev Biol 2021; 9:707268. [PMID: 34395435 PMCID: PMC8355602 DOI: 10.3389/fcell.2021.707268] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 07/09/2021] [Indexed: 12/31/2022] Open
Abstract
Tau is a protein that associates with microtubules (MTs) and promotes their assembly and stability. The protein loses its ability to bind MTs in tauopathies, and detached tau can misfold and induce the pathological changes that characterize Alzheimer’s disease (AD). A growing body of evidence indicates that tauopathies can spread between cells or connected regions. Pathological tau transmission in the brain of patients with AD and other tauopathies is due to the spread of various tau species along neuroanatomically connected regions in a “prion-like” manner. This complex process involves multiple steps of secretion, cellular uptake, transcellular transfer, and/or seeding, but the precise mechanisms of tau pathology propagation remain unclear. This review summarizes the current evidence on the nature of propagative tau species and the possible steps involved in the process of tau pathology spread, including detachment from MTs, degradations, and secretion, and discusses the different mechanisms underlying the spread of tau pathology.
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Affiliation(s)
- Huiqin Zhang
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yu Cao
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Lina Ma
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yun Wei
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hao Li
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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13
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Annadurai N, De Sanctis JB, Hajdúch M, Das V. Tau secretion and propagation: Perspectives for potential preventive interventions in Alzheimer's disease and other tauopathies. Exp Neurol 2021; 343:113756. [PMID: 33989658 DOI: 10.1016/j.expneurol.2021.113756] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/26/2021] [Accepted: 05/10/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is characterised by the accumulation of intracytoplasmic aggregates of tau protein, which are suggested to spread in a prion-like manner between interconnected brain regions. This spreading is mediated by the secretion and uptake of tau from the extracellular space or direct cell-to-cell transmission through cellular protrusions. The prion-like tau then converts the endogenous, normal tau into pathological forms, resulting in neurodegeneration. The endoplasmic reticulum/Golgi-independent tau secretion through unconventional secretory pathways involves delivering misfolded and aggregated tau to the plasma membrane and its release into the extracellular space by non-vesicular and vesicular mechanisms. Although cytoplasmic tau was thought to be released only from degenerating cells, studies now show that cells constitutively secrete tau at low levels under physiological conditions. The mechanisms of secretion of tau under physiological and pathological conditions remain unclear. Therefore, a better understanding of these pathways is essential for developing therapeutic approaches that can target prion-like tau forms to prevent neurodegeneration progression in AD. This review focuses on unconventional secretion pathways involved in the spread of tau pathology in AD and presents these pathways as prospective areas for future AD drug discovery and development.
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Affiliation(s)
- Narendran Annadurai
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 5, 77900 Olomouc, Czech Republic
| | - Juan B De Sanctis
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 5, 77900 Olomouc, Czech Republic
| | - Marián Hajdúch
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 5, 77900 Olomouc, Czech Republic
| | - Viswanath Das
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 5, 77900 Olomouc, Czech Republic.
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14
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Kobro-Flatmoen A, Lagartos-Donate MJ, Aman Y, Edison P, Witter MP, Fang EF. Re-emphasizing early Alzheimer's disease pathology starting in select entorhinal neurons, with a special focus on mitophagy. Ageing Res Rev 2021; 67:101307. [PMID: 33621703 DOI: 10.1016/j.arr.2021.101307] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/04/2021] [Accepted: 02/18/2021] [Indexed: 12/31/2022]
Abstract
The entorhinal-hippocampal system contains distinct networks subserving declarative memory. This system is selectively vulnerable to changes of ageing and pathological processes. The entorhinal cortex (EC) is a pivotal component of this memory system since it serves as the interface between the neocortex and the hippocampus. EC is heavily affected by the proteinopathies of Alzheimer's disease (AD). These appear in a stereotypical spatiotemporal manner and include increased levels of intracellular amyloid-beta Aβ (iAβ), parenchymal deposition of Aβ plaques, and neurofibrillary tangles (NFTs) containing abnormally processed Tau. Increased levels of iAβ and the formation of NFTs are seen very early on in a population of neurons belonging to EC layer II (EC LII), and recent evidence leads us to believe that this population is made up of highly energy-demanding reelin-positive (RE+) projection neurons. Mitochondria are fundamental to the energy supply, metabolism, and plasticity of neurons. Evidence from AD postmortem brain tissues supports the notion that mitochondrial dysfunction is one of the initial pathological events in AD, and this is likely to take place in the vulnerable RE + EC LII neurons. Here we review and discuss these notions, anchored to the anatomy of AD, and formulate a hypothesis attempting to explain the vulnerability of RE + EC LII neurons to the formation of NFTs. We attempt to link impaired mitochondrial clearance to iAβ and signaling involving both apolipoprotein 4 and reelin, and argue for their relevance to the formation of NFTs specifically in RE + EC LII neurons during the prodromal stages of AD. We believe future studies on these interactions holds promise to advance our understanding of AD etiology and provide new ideas for drug development.
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15
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Tavassoly O, Del Cid Pellitero E, Larroquette F, Cai E, Thomas RA, Soubannier V, Luo W, Durcan TM, Fon EA. Pharmacological Inhibition of Brain EGFR Activation By a BBB-penetrating Inhibitor, AZD3759, Attenuates α-synuclein Pathology in a Mouse Model of α-Synuclein Propagation. Neurotherapeutics 2021; 18:979-997. [PMID: 33713002 PMCID: PMC8423974 DOI: 10.1007/s13311-021-01017-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2021] [Indexed: 12/18/2022] Open
Abstract
Aggregation and deposition of α-synuclein (α-syn) in Lewy bodies within dopamine neurons of substantia nigra (SN) is the pathological hallmark of Parkinson's disease (PD). These toxic α-syn aggregates are believed to propagate from neuron-to-neuron and spread the α-syn pathology throughout the brain beyond dopamine neurons in a prion-like manner. Targeting propagation of such α-syn aggregates is of high interest but requires identifying pathways involving in this process. Evidence from previous Alzheimer's disease reports suggests that EGFR may be involved in the prion-like propagation and seeding of amyloid-β. We show here that EGFR regulates the uptake of exogenous α-syn-PFFs and the levels of endogenous α-syn in cell cultures and a mouse model of α-syn propagation, respectively. Thus, we tested the therapeutic potentials of AZD3759, a highly selective BBB-penetrating EGFR inhibitor, in a preclinical mouse model of α-syn propagation. AZD3759 decreases activated EGFR levels in the brain and reduces phosphorylated α-synuclein (pSyn) pathology in brain sections, including striatum and SN. As AZD3759 is already in the clinic, this paper's results suggest a possible repositioning of AZD3759 as a disease-modifying approach for PD.
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Affiliation(s)
- Omid Tavassoly
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada.
- McGill Parkinson Program and Neurodegenerative Diseases Group, Montreal Neurological Institute, McGill University, Montréal, QC, Canada.
| | - Esther Del Cid Pellitero
- McGill Parkinson Program and Neurodegenerative Diseases Group, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Frederique Larroquette
- McGill Parkinson Program and Neurodegenerative Diseases Group, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Eddie Cai
- McGill Parkinson Program and Neurodegenerative Diseases Group, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
- Early Drug Discovery Unit, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Rhalena A Thomas
- McGill Parkinson Program and Neurodegenerative Diseases Group, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
- Early Drug Discovery Unit, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Vincent Soubannier
- Early Drug Discovery Unit, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Wen Luo
- Early Drug Discovery Unit, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Thomas M Durcan
- Early Drug Discovery Unit, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Edward A Fon
- McGill Parkinson Program and Neurodegenerative Diseases Group, Montreal Neurological Institute, McGill University, Montréal, QC, Canada.
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16
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Latent patterns of task-related functional connectivity in relation to regions of hyperactivation in individuals at risk of Alzheimer's disease. NEUROIMAGE-CLINICAL 2021; 30:102643. [PMID: 33813263 PMCID: PMC8050799 DOI: 10.1016/j.nicl.2021.102643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 11/23/2022]
Abstract
Hyperactivation relates to memory-related network dysfunction in SCD+ and MCI. Hippocampal hyperactivation and connectivity relate to worst memory performance. In contrast, neocortical hyperactivation and connectivity may reflect compensation.
The goal of this study was to assess how task-related hyperactivation relates to brain network dysfunction and memory performance in individuals at risk of Alzheimer’s disease (AD). Eighty participants from the CIMA-Q cohort were included, of which 28 had subjective cognitive decline plus (SCD+), as they had memory complaints and worries in addition to a smaller hippocampal volume and/or an APOE4 allele, 26 had amnestic mild cognitive impairment (MCI) and 26 were healthy controls without memory complaints. Functional magnetic resonance imaging (fMRI) activation was measured during an object-location memory task. Seed-partial least square analyses (seed-PLS) were conducted in controls and in the SCD+/MCI groups to yield sets of orthogonal latent variables (LVs) assessing the triple association between: i) seed activity in brain regions found to be hyperactive in individuals at risk of AD (left hippocampus, left superior parietal lobule, right inferior temporal lobe), ii) latent patterns of whole-brain task-related activation, and iii) associative memory performance. Three LVs in the SCD+ and MCI groups (67.88% of total covariance explained) and two LVs in the controls (77.85% of total covariance explained) were significant. While controls and SCD+/MCI groups shared a common pattern of memory-related connectivity, patterns of hyperactivation-networks interactions were unique to the clinical groups. Interestingly, higher hippocampal connectivity was associated with poorer memory performance whereas higher neocortical connectivity predicted better memory performance in SCD+ and MCI groups. Our data provides empirical evidence that early dysfunction in brain activation and connectivity is present in the very early stages of AD and offers new insights on the relationship between functional brain alterations and memory performance.
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17
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Weber AJ, Herskowitz JH. Perspectives on ROCK2 as a Therapeutic Target for Alzheimer's Disease. Front Cell Neurosci 2021; 15:636017. [PMID: 33790742 PMCID: PMC8005730 DOI: 10.3389/fncel.2021.636017] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/19/2021] [Indexed: 12/12/2022] Open
Abstract
Rho-associated coiled-coil containing kinase isoform 2 (ROCK2) is a member of the AGC family of serine/threonine kinases and an extensively studied regulator of actin-mediated cytoskeleton contractility. Over the past decade, new evidence has emerged that suggests ROCK2 regulates autophagy. Recent studies indicate that dysregulation of autophagy contributes to the development of misfolded tau aggregates among entorhinal cortex (EC) excitatory neurons in early Alzheimer's disease (AD). While the accumulation of tau oligomers and fibrils is toxic to neurons, autophagy facilitates the degradation of these pathologic species and represents a major cellular pathway for tau disposal in neurons. ROCK2 is expressed in excitatory neurons and pharmacologic inhibition of ROCK2 can induce autophagy pathways. In this mini-review, we explore potential mechanisms by which ROCK2 mediates autophagy and actin dynamics and discuss how these pathways represent therapeutic avenues for Alzheimer's disease.
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Affiliation(s)
| | - Jeremy H. Herskowitz
- Center for Neurodegeneration and Experimental Therapeutics, Departments of Neurology and Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
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18
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Chang CW, Shao E, Mucke L. Tau: Enabler of diverse brain disorders and target of rapidly evolving therapeutic strategies. Science 2021; 371:371/6532/eabb8255. [PMID: 33632820 DOI: 10.1126/science.abb8255] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Several lines of evidence implicate the protein tau in the pathogenesis of multiple brain disorders, including Alzheimer's disease, other neurodegenerative conditions, autism, and epilepsy. Tau is abundant in neurons and interacts with microtubules, but its main functions in the brain remain to be defined. These functions may involve the regulation of signaling pathways relevant to diverse biological processes. Informative disease models have revealed a plethora of abnormal tau species and mechanisms that might contribute to neuronal dysfunction and loss, but the relative importance of their respective contributions is uncertain. This knowledge gap poses major obstacles to the development of truly impactful therapeutic strategies. The current expansion and intensification of efforts to translate mechanistic insights into tau-related therapeutics should address this issue and could deliver better treatments for a host of devastating conditions.
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Affiliation(s)
- Che-Wei Chang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Eric Shao
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA. .,Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, USA
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19
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Holloway PM, Willaime-Morawek S, Siow R, Barber M, Owens RM, Sharma AD, Rowan W, Hill E, Zagnoni M. Advances in microfluidic in vitro systems for neurological disease modeling. J Neurosci Res 2021; 99:1276-1307. [PMID: 33583054 DOI: 10.1002/jnr.24794] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/21/2020] [Accepted: 12/19/2020] [Indexed: 12/19/2022]
Abstract
Neurological disorders are the leading cause of disability and the second largest cause of death worldwide. Despite significant research efforts, neurology remains one of the most failure-prone areas of drug development. The complexity of the human brain, boundaries to examining the brain directly in vivo, and the significant evolutionary gap between animal models and humans, all serve to hamper translational success. Recent advances in microfluidic in vitro models have provided new opportunities to study human cells with enhanced physiological relevance. The ability to precisely micro-engineer cell-scale architecture, tailoring form and function, has allowed for detailed dissection of cell biology using microphysiological systems (MPS) of varying complexities from single cell systems to "Organ-on-chip" models. Simplified neuronal networks have allowed for unique insights into neuronal transport and neurogenesis, while more complex 3D heterotypic cellular models such as neurovascular unit mimetics and "Organ-on-chip" systems have enabled new understanding of metabolic coupling and blood-brain barrier transport. These systems are now being developed beyond MPS toward disease specific micro-pathophysiological systems, moving from "Organ-on-chip" to "Disease-on-chip." This review gives an outline of current state of the art in microfluidic technologies for neurological disease research, discussing the challenges and limitations while highlighting the benefits and potential of integrating technologies. We provide examples of where such toolsets have enabled novel insights and how these technologies may empower future investigation into neurological diseases.
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Affiliation(s)
- Paul M Holloway
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | | | - Richard Siow
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Melissa Barber
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Róisín M Owens
- Department Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Anup D Sharma
- New Orleans BioInnovation Center, AxoSim Inc., New Orleans, LA, USA
| | - Wendy Rowan
- Novel Human Genetics Research Unit, GSK R&D, Stevenage, UK
| | - Eric Hill
- School of Life and Health sciences, Aston University, Birmingham, UK
| | - Michele Zagnoni
- Electronic and Electrical Engineering, University of Strathclyde, Glasgow, UK
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20
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Pedrioli G, Paganetti P. Hijacking Endocytosis and Autophagy in Extracellular Vesicle Communication: Where the Inside Meets the Outside. Front Cell Dev Biol 2021; 8:595515. [PMID: 33490063 PMCID: PMC7817780 DOI: 10.3389/fcell.2020.595515] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 11/18/2020] [Indexed: 12/25/2022] Open
Abstract
Extracellular vesicles, phospholipid bilayer-membrane vesicles of cellular origin, are emerging as nanocarriers of biological information between cells. Extracellular vesicles transport virtually all biologically active macromolecules (e.g., nucleotides, lipids, and proteins), thus eliciting phenotypic changes in recipient cells. However, we only partially understand the cellular mechanisms driving the encounter of a soluble ligand transported in the lumen of extracellular vesicles with its cytosolic receptor: a step required to evoke a biologically relevant response. In this context, we review herein current evidence supporting the role of two well-described cellular transport pathways: the endocytic pathway as the main entry route for extracellular vesicles and the autophagic pathway driving lysosomal degradation of cytosolic proteins. The interplay between these pathways may result in the target engagement between an extracellular vesicle cargo protein and its cytosolic target within the acidic compartments of the cell. This mechanism of cell-to-cell communication may well own possible implications in the pathogenesis of neurodegenerative disorders.
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Affiliation(s)
- Giona Pedrioli
- Neurodegeneration Research Group, Laboratory for Biomedical Neurosciences, Neurocenter of Southern Switzerland, Ente Ospedaliero Cantonale, Torricella-Taverne, Switzerland
- Member of the International Ph.D. Program of the Biozentrum, University of Basel, Basel, Switzerland
| | - Paolo Paganetti
- Neurodegeneration Research Group, Laboratory for Biomedical Neurosciences, Neurocenter of Southern Switzerland, Ente Ospedaliero Cantonale, Torricella-Taverne, Switzerland
- Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
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21
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Masnata M, Salem S, de Rus Jacquet A, Anwer M, Cicchetti F. Targeting Tau to Treat Clinical Features of Huntington's Disease. Front Neurol 2020; 11:580732. [PMID: 33329322 PMCID: PMC7710872 DOI: 10.3389/fneur.2020.580732] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/17/2020] [Indexed: 12/16/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by severe motor, cognitive and psychiatric impairments. While motor deficits often confirm diagnosis, cognitive dysfunctions usually manifest early in the disease process and are consistently ranked among the leading factors that impact the patients' quality of life. The genetic component of HD, a mutation in the huntingtin (HTT) gene, is traditionally presented as the main contributor to disease pathology. However, accumulating evidence suggests the implication of the microtubule-associated tau protein to the pathogenesis and therefore, proposes an alternative conceptual framework where tau and mutant huntingtin (mHTT) act conjointly to drive neurodegeneration and cognitive dysfunction. This perspective on disease etiology offers new avenues to design therapeutic interventions and could leverage decades of research on Alzheimer's disease (AD) and other tauopathies to rapidly advance drug discovery. In this mini review, we examine the breadth of tau-targeting treatments currently tested in the preclinical and clinical settings for AD and other tauopathies, and discuss the potential application of these strategies to HD.
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Affiliation(s)
- Maria Masnata
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada
| | - Shireen Salem
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada
| | - Aurelie de Rus Jacquet
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada
| | - Mehwish Anwer
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada
| | - Francesca Cicchetti
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada.,Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada
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22
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Bell BJ, Malvankar MM, Tallon C, Slusher BS. Sowing the Seeds of Discovery: Tau-Propagation Models of Alzheimer's Disease. ACS Chem Neurosci 2020; 11:3499-3509. [PMID: 33050700 DOI: 10.1021/acschemneuro.0c00531] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The propagation of pathological proteins throughout the brain is the primary physiological hallmark of the progression of Alzheimer's Disease (AD). A growing body of evidence indicates that hyperphosphorylated Tau proteins are spread transcellularly between neurons in a prionlike fashion, inducing misfolding and aggregation into neurofibrillary tangles which accumulate along specific connectivity pathways. Earlier transgenic rodent AD models did not capture this disease-relevant spread, and therefore, seeded Tau-propagation models have been developed. Here, mutant human Tau (as isolated protein or packaged into an adeno-associated virus (AAV) viral vector) is stereotaxically injected into select brain regions and its histopathological propagation to downstream neurons quantified. These models offer a faster and more direct mechanism to evaluate genetic components and therapeutic approaches which attenuate Tau spreading in vivo. Recently, these Tau-seeding models have revealed several new targets for AD drug discovery, including nSMase2, SIRT1, p300/CBP, LRP1, and TYROBP, as well as the potential therapeutics based on melatonin and chondroitinase ABC. Importantly, these Tau-propagation rodent models more closely phenocopy the progression of AD in humans and are therefore likely to improve preclinical studies and derisk future moves into clinical trials.
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Affiliation(s)
- Benjamin J. Bell
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Medhinee M. Malvankar
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Carolyn Tallon
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Barbara S. Slusher
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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Perez-Rando M, Dujardin S, Bennett RE, Commins C, Nibhanupudy T, Hyman BT. Synaptic and metabolic gene expression alterations in neurons that are recipients of proteopathic tau seeds. Acta Neuropathol Commun 2020; 8:168. [PMID: 33076986 PMCID: PMC7574323 DOI: 10.1186/s40478-020-01049-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 10/02/2020] [Indexed: 01/07/2023] Open
Abstract
Recent studies suggest that misfolded tau molecules can be released, and taken up by adjacent neurons, propagating proteopathic seeds across neural systems. Yet critical to understanding whether tau propagation is relevant in pathophysiology of disease would be to learn if it alters neuronal properties. We utilized high resolution multi-color in situ hybridization technology, RNAScope, in a well-established tau transgenic animal, and found that a subset of neurons in the cortex do not appear to express the transgene, but do develop phospho-tau positive inclusions, consistent with having received tau seeds. Recipient neurons show decreases in their expression of synaptophysin, CAMKIIα, and mouse tau in both young and old animals. These results contrast with neurons that develop tau aggregates and also overexpress the transgene, which have few changes in expression of metabolic and synaptic markers. Taken together, these results strongly suggest that tau propagation impacts neuronal functional integrity.
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Affiliation(s)
- Marta Perez-Rando
- grid.32224.350000 0004 0386 9924Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Building 114, Room 2009, Charlestown, MA 02129 USA ,grid.38142.3c000000041936754XHarvard Medical School, Boston, MA USA
| | - Simon Dujardin
- grid.32224.350000 0004 0386 9924Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Building 114, Room 2009, Charlestown, MA 02129 USA ,grid.38142.3c000000041936754XHarvard Medical School, Boston, MA USA
| | - Rachel E. Bennett
- grid.32224.350000 0004 0386 9924Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Building 114, Room 2009, Charlestown, MA 02129 USA ,grid.38142.3c000000041936754XHarvard Medical School, Boston, MA USA
| | - Caitlin Commins
- grid.32224.350000 0004 0386 9924Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Building 114, Room 2009, Charlestown, MA 02129 USA
| | - Tara Nibhanupudy
- grid.32224.350000 0004 0386 9924Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Building 114, Room 2009, Charlestown, MA 02129 USA
| | - Bradley T. Hyman
- grid.32224.350000 0004 0386 9924Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Building 114, Room 2009, Charlestown, MA 02129 USA ,grid.38142.3c000000041936754XHarvard Medical School, Boston, MA USA
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Goedert M. Tau proteinopathies and the prion concept. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:239-259. [PMID: 32958235 DOI: 10.1016/bs.pmbts.2020.08.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The ordered assembly of a small number of proteins into amyloid filaments is central to age-related neurodegenerative diseases. Tau is the most commonly affected of these proteins. In sporadic diseases, assemblies of tau form in a stochastic manner in certain brain regions, from where they appear to spread in a deterministic way, giving rise to disease symptoms. Over the past decade, multiple lines of evidence have shown that assembled tau behaves like a prion. More recently, electron cryo-microscopy of tau filaments has shown that distinct conformers are present in different diseases, with no inter-individual variation for a given disease.
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Affiliation(s)
- Michel Goedert
- MRC Laboratory Molecular Biology, Cambridge, United Kingdom.
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25
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Wiersma VI, Hoozemans JJM, Scheper W. Untangling the origin and function of granulovacuolar degeneration bodies in neurodegenerative proteinopathies. Acta Neuropathol Commun 2020; 8:153. [PMID: 32883341 PMCID: PMC7469111 DOI: 10.1186/s40478-020-00996-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 07/14/2020] [Indexed: 12/13/2022] Open
Abstract
In the brains of tauopathy patients, tau pathology coincides with the presence of granulovacuolar degeneration bodies (GVBs) both at the regional and cellular level. Recently, it was shown that intracellular tau pathology causes GVB formation in experimental models thus explaining the strong correlation between these neuropathological hallmarks in the human brain. These novel models of GVB formation provide opportunities for future research into GVB biology, but also urge reevaluation of previous post-mortem observations. Here, we review neuropathological data on GVBs in tauopathies and other neurodegenerative proteinopathies. We discuss the possibility that intracellular aggregates composed of proteins other than tau are also able to induce GVB formation. Furthermore, the potential mechanisms of GVB formation and the downstream functional implications hereof are outlined in view of the current available data. In addition, we provide guidelines for the identification of GVBs in tissue and cell models that will help to facilitate and streamline research towards the elucidation of the role of these enigmatic and understudied structures in neurodegeneration.
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De La-Rocque S, Moretto E, Butnaru I, Schiavo G. Knockin' on heaven's door: Molecular mechanisms of neuronal tau uptake. J Neurochem 2020; 156:563-588. [PMID: 32770783 PMCID: PMC8432157 DOI: 10.1111/jnc.15144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/31/2020] [Accepted: 08/03/2020] [Indexed: 12/18/2022]
Abstract
Since aggregates of the microtubule‐binding protein tau were found to be the main component of neurofibrillary tangles more than 30 years ago, their contribution to neurodegeneration in Alzheimer's disease (AD) and tauopathies has become well established. Recent work shows that both tau load and its distribution in the brain of AD patients correlate with cognitive decline more closely compared to amyloid plaque deposition. In addition, the amyloid cascade hypothesis has been recently challenged because of disappointing results of clinical trials designed to treat AD by reducing beta‐amyloid levels, thus fuelling a renewed interest in tau. There is now robust evidence to indicate that tau pathology can spread within the central nervous system via a prion‐like mechanism following a stereotypical pattern, which can be explained by the trans‐synaptic inter‐neuronal transfer of pathological tau. In the receiving neuron, tau has been shown to take multiple routes of internalisation, which are partially dependent on its conformation and aggregation status. Here, we review the emerging mechanisms proposed for the uptake of extracellular tau in neurons and the requirements for the propagation of its pathological conformers, addressing how they gain access to physiological tau monomers in the cytosol. Furthermore, we highlight some of the key mechanistic gaps of the field, which urgently need to be addressed to expand our understanding of tau propagation and lead to the identification of new therapeutic strategies for tauopathies.
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Affiliation(s)
- Samantha De La-Rocque
- UK Dementia Research Institute, University College London, London, UK.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Edoardo Moretto
- UK Dementia Research Institute, University College London, London, UK
| | - Ioana Butnaru
- UK Dementia Research Institute, University College London, London, UK
| | - Giampietro Schiavo
- UK Dementia Research Institute, University College London, London, UK.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
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27
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Hallinan GI, Lopez DM, Vargas-Caballero M, West J, Deinhardt K. Co-culture of Murine Neurons Using a Microfluidic Device for The Study of Tau Misfolding Propagation. Bio Protoc 2020; 10:e3718. [PMID: 33659382 DOI: 10.21769/bioprotoc.3718] [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: 03/13/2020] [Revised: 06/21/2020] [Accepted: 06/28/2020] [Indexed: 11/02/2022] Open
Abstract
The deposition of misfolded, aggregated tau protein is a hallmark of several neurodegenerative diseases, collectively termed "tauopathies". Tau pathology spreads throughout the brain along connected pathways in a prion-like manner. The process of tau pathology propagation across circuits is a focus of intense research and has been investigated in vivo in human post-mortem brain and in mouse models of the diseases, in vitro in diverse cellular systems including primary neurons, and in cell free assays using purified recombinant tau protein. Here we describe a protocol that takes advantage of a minimalistic neuronal circuit arrayed within a microfluidic device to follow the propagation of tau misfolding from a presynaptic to a postsynaptic neuron. This assay allows high-resolution imaging as well as individual manipulation of the releasing and receiving neuron, and is therefore beneficial for investigating the propagation of tau and other misfolded proteins in vitro.
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Affiliation(s)
- Grace I Hallinan
- School of Biological Sciences, University of Southampton, Southampton, UK
| | - Dianne M Lopez
- School of Biological Sciences, University of Southampton, Southampton, UK
| | | | - Jonathan West
- Faculty of Medicine and Centre for Hybrid Biodevices, University of Southampton, Southampton, UK
| | - Katrin Deinhardt
- School of Biological Sciences, University of Southampton, Southampton, UK
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Jiao H, Downie LE, Huang X, Wu M, Oberrauch S, Keenan RJ, Jacobson LH, Chinnery HR. Novel alterations in corneal neuroimmune phenotypes in mice with central nervous system tauopathy. J Neuroinflammation 2020; 17:136. [PMID: 32345316 PMCID: PMC7189727 DOI: 10.1186/s12974-020-01803-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 04/03/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Tauopathy in the central nervous system (CNS) is a histopathological hallmark of frontotemporal dementia (FTD) and Alzheimer's disease (AD). Although AD is accompanied by various ocular changes, the effects of tauopathy on the integrity of the cornea, which is densely innervated by the peripheral nervous system and is populated by resident dendritic cells, is still unknown. The aim of this study was to investigate if neuroimmune interactions in the cornea are affected by CNS tauopathy. METHODS Corneas from wild type (WT) and transgenic rTg4510 mice that express the P301L tau mutation were examined at 2, 6, 8, and 11 months. Clinical assessment of the anterior segment of the eye was performed using spectral domain optical coherence tomography. The density of the corneal epithelial sensory nerves and the number and field area of resident epithelial dendritic cells were assessed using immunofluorescence. The immunological activation state of corneal and splenic dendritic cells was examined using flow cytometry and compared between the two genotypes at 9 months of age. RESULTS Compared to age-matched WT mice, rTg4510 mice had a significantly lower density of corneal nerve axons at both 8 and 11 months of age. Corneal nerves in rTg4510 mice also displayed a higher percentage of beaded nerve axons and a lower density of epithelial dendritic cells compared to WT mice. From 6 months of age, the size of the corneal dendritic cells was significantly smaller in rTg4510 compared to WT mice. Phenotypic characterization by flow cytometry demonstrated an activated state of dendritic cells (CD86+ and CD45+ CD11b+CD11c+) in the corneas of rTg4510 compared to WT mice, with no distinct changes in the spleen monocytes/dendritic cells. At 2 months of age, there were no significant differences in the neural or immune structures between the two genotypes. CONCLUSIONS Corneal sensory nerves and epithelial dendritic cells were altered in the rTg4510 mouse model of tauopathy, with temporal changes observed with aging. The activation of corneal dendritic cells prior to the gradual loss of neighboring sensory nerves suggests an early involvement of corneal immune cells in tau-associated pathology originating in the CNS.
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Affiliation(s)
- Haihan Jiao
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
| | - Laura E Downie
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
| | - Xin Huang
- Innate Phagocytosis Laboratory, Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| | - Mengliang Wu
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
| | - Sara Oberrauch
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Australia.,Sleep and Cognition Laboratory, Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| | - Ryan J Keenan
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Australia.,Sleep and Cognition Laboratory, Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| | - Laura H Jacobson
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Australia. .,Sleep and Cognition Laboratory, Florey Institute of Neuroscience and Mental Health, Parkville, Australia.
| | - Holly R Chinnery
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia.
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Zhang Y, Huang N, Lu H, Huang J, Jin H, Shi J, Jin F. Icariin protects against sodium azide-induced neurotoxicity by activating the PI3K/Akt/GSK-3β signaling pathway. PeerJ 2020; 8:e8955. [PMID: 32341897 PMCID: PMC7179568 DOI: 10.7717/peerj.8955] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/21/2020] [Indexed: 01/22/2023] Open
Abstract
Background Icariin (ICA) is one of the major active flavonoids extracted from the traditional Chinese herb Epimedium brevicornum Maxim and has been shown to have neuroprotective effects. This study was designed to investigate the effect of ICA on sodium azide (NaN3)-induced rat adrenal pheochromocytoma (PC12) cell damage and to further examine the underlying mechanisms. Methods To explore its possible mechanism, we used NaN3 (50 mM)-induced neuronal PC12 cell damage. Cell viability was evaluated by CCK-8 and lactate dehydrogenase (LDH) assays. Mitochondrial membrane potential (MMP) was detected by JC-1. Glucose concentration was assessed by the glucose oxidase method. The role of ICA in the PI3K/Akt/GSK-3β signaling pathway was explored by Western blotting. Results The results indicate that pretreatment with ICA reduced NaN3-induced cell damage and significantly reduced the leakage rate of LDH in PC12 cells. ICA pretreatment increased the MMP and a decrease in glucose concentration indicate increased glucose consumption. Furthermore, the protein levels of p-PI3K (p85), PI3K-110α, p-Ser473-Akt and p-Ser9-GSK-3β were markedly decreased in PC12 cells after NaN3 treatment for 24 h, whereas these effects were reverted after pretreatment with ICA. Tau phosphorylation at the Ser396/404 and Thr217 sites was significantly decreased by pretreatment with ICA. Conclusions These results suggest that ICA protects against NaN3-induced neurotoxicity in PC12 cells by activating the PI3K/Akt/GSK-3β signaling pathway.
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Affiliation(s)
- Ying Zhang
- Key Laboratory of Basic Pharmacology and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China.,Department of Pharmacy, People's Hospital of Zhongmu, Zhengzhou, Henan, China
| | - Nanqu Huang
- National Drug Clinical Trial Institution, The Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi, Guizhou, China
| | - Hao Lu
- Key Laboratory of Basic Pharmacology and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Juan Huang
- Key Laboratory of Basic Pharmacology and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China.,School of Public Health, Zunyi Medical University, Zunyi, Guizhou, China
| | - Hai Jin
- Institute of Digestive Diseases of Affiliated Hospital, Zunyi Medical University, Zunyi, Guizhou, China
| | - Jingshan Shi
- Key Laboratory of Basic Pharmacology and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Feng Jin
- Key Laboratory of Basic Pharmacology and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
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