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Scharf A, Gührs KH, von Mikecz A. Anti-amyloid compounds protect from silica nanoparticle-induced neurotoxicity in the nematode C. elegans. Nanotoxicology 2015; 10:426-35. [PMID: 26444998 PMCID: PMC4819850 DOI: 10.3109/17435390.2015.1073399] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Identifying nanomaterial-bio-interactions are imperative due to the broad introduction of nanoparticle (NP) applications and their distribution. Here, we demonstrate that silica NPs effect widespread protein aggregation in the soil nematode Caenorhabditis elegans ranging from induction of amyloid in nucleoli of intestinal cells to facilitation of protein aggregation in body wall muscles and axons of neural cells. Proteomic screening revealed that exposure of adult C. elegans with silica NPs promotes segregation of proteins belonging to the gene ontology (GO) group of “protein folding, proteolysis and stress response” to an SDS-resistant aggregome network. Candidate proteins in this group include chaperones, heat shock proteins and subunits of the 26S proteasome which are all decisively involved in protein homeostasis. The pathway of protein homeostasis was validated as a major target of silica NPs by behavioral phenotyping, as inhibitors of amyloid formation rescued NP-induced defects of locomotory patterns and egg laying. The analysis of a reporter worm for serotonergic neural cells revealed that silica NP-induced protein aggregation likewise occurs in axons of HSN neurons, where presynaptic accumulation of serotonin, e.g. disturbed axonal transport reduces the capacity for neurotransmission and egg laying. The results suggest that in C. elegans silica NPs promote a cascade of events including disturbance of protein homeostasis, widespread protein aggregation and inhibition of serotonergic neurotransmission which can be interrupted by compounds preventing amyloid fibrillation.
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Affiliation(s)
- Andrea Scharf
- a IUF - Leibniz Research Institute for Environmental Medicine at the Heinrich-Heine-University Duesseldorf , Düsseldorf , Germany and
| | - Karl-Heinz Gührs
- b CF Proteomics, FLI-Leibniz-Institute for Age Research, Fritz-Lipman-Institute e.V. , Jena , Germany
| | - Anna von Mikecz
- a IUF - Leibniz Research Institute for Environmental Medicine at the Heinrich-Heine-University Duesseldorf , Düsseldorf , Germany and
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Pakavathkumar P, Sharma G, Kaushal V, Foveau B, LeBlanc AC. Methylene Blue Inhibits Caspases by Oxidation of the Catalytic Cysteine. Sci Rep 2015; 5:13730. [PMID: 26400108 PMCID: PMC4585840 DOI: 10.1038/srep13730] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/03/2015] [Indexed: 12/20/2022] Open
Abstract
Methylene blue, currently in phase 3 clinical trials against Alzheimer Disease, disaggregates the Tau protein of neurofibrillary tangles by oxidizing specific cysteine residues. Here, we investigated if methylene blue can inhibit caspases via the oxidation of their active site cysteine. Methylene blue, and derivatives, azure A and azure B competitively inhibited recombinant Caspase-6 (Casp6), and inhibited Casp6 activity in transfected human colon carcinoma cells and in serum-deprived primary human neuron cultures. Methylene blue also inhibited recombinant Casp1 and Casp3. Furthermore, methylene blue inhibited Casp3 activity in an acute mouse model of liver toxicity. Mass spectrometry confirmed methylene blue and azure B oxidation of the catalytic Cys163 cysteine of Casp6. Together, these results show a novel inhibitory mechanism of caspases via sulfenation of the active site cysteine. These results indicate that methylene blue or its derivatives could (1) have an additional effect against Alzheimer Disease by inhibiting brain caspase activity, (2) be used as a drug to prevent caspase activation in other conditions, and (3) predispose chronically treated individuals to cancer via the inhibition of caspases.
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Affiliation(s)
- Prateep Pakavathkumar
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Gyanesh Sharma
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Vikas Kaushal
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Bénédicte Foveau
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Andrea C. LeBlanc
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
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Brelstaff J, Ossola B, Neher JJ, Klingstedt T, Nilsson KPR, Goedert M, Spillantini MG, Tolkovsky AM. The fluorescent pentameric oligothiophene pFTAA identifies filamentous tau in live neurons cultured from adult P301S tau mice. Front Neurosci 2015; 9:184. [PMID: 26074756 PMCID: PMC4448042 DOI: 10.3389/fnins.2015.00184] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/08/2015] [Indexed: 11/15/2022] Open
Abstract
Identification of fluorescent dyes that label the filamentous protein aggregates characteristic of neurodegenerative disease, such as β-amyloid and tau in Alzheimer's disease, in a live cell culture system has previously been a major hurdle. Here we show that pentameric formyl thiophene acetic acid (pFTAA) fulfills this function in living neurons cultured from adult P301S tau transgenic mice. Injection of pFTAA into 5-month-old P301S tau mice detected cortical and DRG neurons immunoreactive for AT100, an antibody that identifies solely filamentous tau, or MC1, an antibody that identifies a conformational change in tau that is commensurate with neurofibrillary tangle formation in Alzheimer's disease brains. In fixed cultures of dorsal root ganglion (DRG) neurons, pFTAA binding, which also identified AT100 or MC1+ve neurons, followed a single, saturable binding curve with a half saturation constant of 0.14 μM, the first reported measurement of a binding affinity of a beta-sheet reactive dye to primary neurons harboring filamentous tau. Treatment with formic acid, which solubilizes filamentous tau, extracted pFTAA, and prevented the re-binding of pFTAA and MC1 without perturbing expression of soluble tau, detected using an anti-human tau (HT7) antibody. In live cultures, pFTAA only identified DRG neurons that, after fixation, were AT100/MC1+ve, confirming that these forms of tau pre-exist in live neurons. The utility of pFTAA to discriminate between living neurons containing filamentous tau from other neurons is demonstrated by showing that more pFTAA+ve neurons die than pFTAA-ve neurons over 25 days. Since pFTAA identifies fibrillar tau and other misfolded proteins in living neurons in culture and in animal models of several neurodegenerative diseases, as well as in human brains, it will have considerable application in sorting out disease mechanisms and in identifying disease-modifying drugs that will ultimately help establish the mechanisms of neurodegeneration in human neurodegenerative diseases.
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Affiliation(s)
- Jack Brelstaff
- Department of Clinical Neurosciences, University of Cambridge Cambridge, UK
| | - Bernardino Ossola
- Department of Clinical Neurosciences, University of Cambridge Cambridge, UK
| | - Jonas J Neher
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen Tübingen, Germany
| | | | | | - Michel Goedert
- Medical Research Council Laboratory of Molecular Biology Cambridge, UK
| | | | - Aviva M Tolkovsky
- Department of Clinical Neurosciences, University of Cambridge Cambridge, UK
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104
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Hochgräfe K, Sydow A, Matenia D, Cadinu D, Könen S, Petrova O, Pickhardt M, Goll P, Morellini F, Mandelkow E, Mandelkow EM. Preventive methylene blue treatment preserves cognition in mice expressing full-length pro-aggregant human Tau. Acta Neuropathol Commun 2015; 3:25. [PMID: 25958115 PMCID: PMC4425867 DOI: 10.1186/s40478-015-0204-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 04/16/2015] [Indexed: 11/21/2022] Open
Abstract
Introduction Neurofibrillary tangles (NFT) composed of Tau are hallmarks of neurodegeneration in Alzheimer disease. Transgenic mice expressing full-length pro-aggregant human Tau (2N4R Tau-ΔK280, termed TauΔK) or its repeat domain (TauRD-ΔK280, TauRDΔK) develop a progressive Tau pathology with missorting, phosphorylation, aggregation of Tau, loss of synapses and functional deficits. Whereas TauRDΔK assembles into NFT concomitant with neuronal death, TauΔK accumulates into Tau pretangles without overt neuronal loss. Both forms cause a comparable cognitive decline (with onset at 10mo and 12mo, respectively), which is rescued upon switch-off of transgene expression. Since methylene blue (MB) is able to inhibit Tau aggregation in vitro, we investigated whether MB can prevent or rescue Tau-induced cognitive impairments in our mouse models. Both types of mice received MB orally using different preventive and therapeutic treatment protocols, initiated either before or after disease onset. The cognitive status of the mice was assessed by behavior tasks (open field, Morris water maze) to determine the most successful conditions for therapeutic intervention. Results Preventive and therapeutic MB application failed to avert or recover learning and memory deficits of TauRDΔK mice. Similarly, therapeutic MB treatment initiated after onset of cognitive impairments was ineffective in TauΔK mice. In contrast, preventive MB application starting before onset of functional deficits preserved cognition of TauΔK mice. Beside improved learning and memory, MB-treated TauΔK mice showed a strong decrease of insoluble Tau, a reduction of conformationally changed (MC1) and phosphorylated Tau species (AT180, PHF1) as well as an upregulation of protein degradation systems (autophagy and proteasome). This argues for additional pleiotropic effects of MB beyond its properties as Tau aggregation inhibitor. Conclusions Our data support the use of Tau aggregation inhibitors as potential drugs for the treatment of AD and other tauopathies and highlights the need for preventive treatment before onset of cognitive impairments. Electronic supplementary material The online version of this article (doi:10.1186/s40478-015-0204-4) contains supplementary material, which is available to authorized users.
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105
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Harrington CR, Storey JMD, Clunas S, Harrington KA, Horsley D, Ishaq A, Kemp SJ, Larch CP, Marshall C, Nicoll SL, Rickard JE, Simpson M, Sinclair JP, Storey LJ, Wischik CM. Cellular Models of Aggregation-dependent Template-directed Proteolysis to Characterize Tau Aggregation Inhibitors for Treatment of Alzheimer Disease. J Biol Chem 2015; 290:10862-75. [PMID: 25759392 PMCID: PMC4409250 DOI: 10.1074/jbc.m114.616029] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Indexed: 12/15/2022] Open
Abstract
Alzheimer disease (AD) is a degenerative tauopathy characterized by aggregation of Tau protein through the repeat domain to form intraneuronal paired helical filaments (PHFs). We report two cell models in which we control the inherent toxicity of the core Tau fragment. These models demonstrate the properties of prion-like recruitment of full-length Tau into an aggregation pathway in which template-directed, endogenous truncation propagates aggregation through the core Tau binding domain. We use these in combination with dissolution of native PHFs to quantify the activity of Tau aggregation inhibitors (TAIs). We report the synthesis of novel stable crystalline leucomethylthioninium salts (LMTX®), which overcome the pharmacokinetic limitations of methylthioninium chloride. LMTX®, as either a dihydromesylate or a dihydrobromide salt, retains TAI activity in vitro and disrupts PHFs isolated from AD brain tissues at 0.16 μM. The Ki value for intracellular TAI activity, which we have been able to determine for the first time, is 0.12 μM. These values are close to the steady state trough brain concentration of methylthioninium ion (0.18 μM) that is required to arrest progression of AD on clinical and imaging end points and the minimum brain concentration (0.13 μM) required to reverse behavioral deficits and pathology in Tau transgenic mice.
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Affiliation(s)
- Charles R Harrington
- From the School of Medicine and Dentistry, University of Aberdeen, Aberdeen AB25 2ZP, United Kingdom, TauRx Therapeutics Ltd., Singapore 068805, and the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - John M D Storey
- TauRx Therapeutics Ltd., Singapore 068805, and the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Scott Clunas
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Kathleen A Harrington
- From the School of Medicine and Dentistry, University of Aberdeen, Aberdeen AB25 2ZP, United Kingdom
| | - David Horsley
- From the School of Medicine and Dentistry, University of Aberdeen, Aberdeen AB25 2ZP, United Kingdom
| | - Ahtsham Ishaq
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Steven J Kemp
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Christopher P Larch
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Colin Marshall
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Sarah L Nicoll
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Janet E Rickard
- From the School of Medicine and Dentistry, University of Aberdeen, Aberdeen AB25 2ZP, United Kingdom
| | - Michael Simpson
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - James P Sinclair
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Lynda J Storey
- the Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Claude M Wischik
- From the School of Medicine and Dentistry, University of Aberdeen, Aberdeen AB25 2ZP, United Kingdom, TauRx Therapeutics Ltd., Singapore 068805, and
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106
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Dujardin S, Colin M, Buée L. Invited review: Animal models of tauopathies and their implications for research/translation into the clinic. Neuropathol Appl Neurobiol 2015; 41:59-80. [DOI: 10.1111/nan.12200] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 11/23/2014] [Indexed: 02/01/2023]
Affiliation(s)
- Simon Dujardin
- Inserm, UMR1172 Jean-Pierre Aubert Research Centre; Lille France
- Faculté de Médecine; Université de Lille; France
- Memory Clinic; CHRU; Lille France
| | - Morvane Colin
- Inserm, UMR1172 Jean-Pierre Aubert Research Centre; Lille France
- Faculté de Médecine; Université de Lille; France
- Memory Clinic; CHRU; Lille France
| | - Luc Buée
- Inserm, UMR1172 Jean-Pierre Aubert Research Centre; Lille France
- Faculté de Médecine; Université de Lille; France
- Memory Clinic; CHRU; Lille France
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107
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Der Perng M, Quinlan RA. The Dynamic Duo of Small Heat Proteins and IFs Maintain Cell Homeostasis, Resist Cellular Stress and Enable Evolution in Cells and Tissues. HEAT SHOCK PROTEINS 2015. [DOI: 10.1007/978-3-319-16077-1_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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108
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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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109
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Combating neurodegenerative disease with chemical probes and model systems. Nat Chem Biol 2014; 10:911-20. [PMID: 25325702 DOI: 10.1038/nchembio.1663] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/11/2014] [Indexed: 12/19/2022]
Abstract
The disheartening results of recent clinical trials for neurodegenerative disease (ND) therapeutics underscore the need for a more comprehensive understanding of the underlying disease biology before effective therapies can be devised. One hallmark of many NDs is a disruption in protein homeostasis. Therefore, investigating the role of protein homeostasis in these diseases is central to delineating their underlying pathobiology. Here, we review the seminal role that chemical biology has played in furthering the research on and treatment of dysfunctional protein homeostasis in NDs. We also discuss the vital and predictive role of model systems in identifying conserved homeostasis pathways and genes therein that are altered in neurodegeneration. Integrating approaches from chemical biology with the use of model systems yields a powerful toolkit with which to unravel the complexities of ND biology.
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110
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Gerson JE, Castillo-Carranza DL, Kayed R. Advances in therapeutics for neurodegenerative tauopathies: moving toward the specific targeting of the most toxic tau species. ACS Chem Neurosci 2014; 5:752-69. [PMID: 25075869 DOI: 10.1021/cn500143n] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neurodegenerative disease is one of the greatest health concerns today and with no effective treatment in sight, it is crucial that researchers find a safe and successful therapeutic. While neurofibrillary tangles are considered the primary tauopathy hallmark, more evidence continues to come to light to suggest that soluble, intermediate tau aggregates--tau oligomers--are the most toxic species in disease. These intermediate tau species may also be responsible for the spread of pathology, suggesting that oligomeric tau may be the best therapeutic target. Here, we summarize results for the modulation of tau by molecular chaperones, small molecules and aggregation inhibitors, post-translational modifications, immunotherapy, other techniques, and future directions.
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Affiliation(s)
- Julia E. Gerson
- Department
of Neurology, George and Cynthia Mitchell
Center for Alzheimer’s Disease Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Diana L. Castillo-Carranza
- Department
of Neurology, George and Cynthia Mitchell
Center for Alzheimer’s Disease Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Rakez Kayed
- Department
of Neurology, George and Cynthia Mitchell
Center for Alzheimer’s Disease Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
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111
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Nussbaum-Krammer CI, Morimoto RI. Caenorhabditis elegans as a model system for studying non-cell-autonomous mechanisms in protein-misfolding diseases. Dis Model Mech 2014; 7:31-9. [PMID: 24396152 PMCID: PMC3882046 DOI: 10.1242/dmm.013011] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Caenorhabditis elegans has a number of distinct advantages that are useful for understanding the basis for cellular and organismal dysfunction underlying age-associated diseases of protein misfolding. Although protein aggregation, a key feature of human neurodegenerative diseases, has been typically explored in vivo at the single-cell level using cells in culture, there is now increasing evidence that proteotoxicity has a non-cell-autonomous component and is communicated between cells and tissues in a multicellular organism. These discoveries have opened up new avenues for the use of C. elegans as an ideal animal model system to study non-cell-autonomous proteotoxicity, prion-like propagation of aggregation-prone proteins, and the organismal regulation of stress responses and proteostasis. This Review focuses on recent evidence that C. elegans has mechanisms to transmit certain classes of toxic proteins between tissues and a complex stress response that integrates and coordinates signals from single cells and tissues across the organism. These findings emphasize the potential of C. elegans to provide insights into non-cell-autonomous proteotoxic mechanisms underlying age-related protein-misfolding diseases.
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Affiliation(s)
- Carmen I Nussbaum-Krammer
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, 2205 Tech Drive, Evanston, IL 60208, USA
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112
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Alexander AG, Marfil V, Li C. Use of Caenorhabditis elegans as a model to study Alzheimer's disease and other neurodegenerative diseases. Front Genet 2014; 5:279. [PMID: 25250042 PMCID: PMC4155875 DOI: 10.3389/fgene.2014.00279] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 07/31/2014] [Indexed: 12/12/2022] Open
Abstract
Advances in research and technology has increased our quality of life, allowed us to combat diseases, and achieve increased longevity. Unfortunately, increased longevity is accompanied by a rise in the incidences of age-related diseases such as Alzheimer’s disease (AD). AD is the sixth leading cause of death, and one of the leading causes of dementia amongst the aged population in the USA. It is a progressive neurodegenerative disorder, characterized by the prevalence of extracellular Aβ plaques and intracellular neurofibrillary tangles, derived from the proteolysis of the amyloid precursor protein (APP) and the hyperphosphorylation of microtubule-associated protein tau, respectively. Despite years of extensive research, the molecular mechanisms that underlie the pathology of AD remain unclear. Model organisms, such as the nematode, Caenorhabditis elegans, present a complementary approach to addressing these questions. C. elegans has many advantages as a model system to study AD and other neurodegenerative diseases. Like their mammalian counterparts, they have complex biochemical pathways, most of which are conserved. Genes in which mutations are correlated with AD have counterparts in C. elegans, including an APP-related gene, apl-1, a tau homolog, ptl-1, and presenilin homologs, such as sel-12 and hop-1. Since the neuronal connectivity in C. elegans has already been established, C. elegans is also advantageous in modeling learning and memory impairments seen during AD. This article addresses the insights C. elegans provide in studying AD and other neurodegenerative diseases. Additionally, we explore the advantages and drawbacks associated with using this model.
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Affiliation(s)
- Adanna G Alexander
- Department of Biology, City College of New York New York, NY, USA ; Department of Biology, The Graduate Center, City University of New York New York, NY, USA
| | - Vanessa Marfil
- Department of Biology, City College of New York New York, NY, USA
| | - Chris Li
- Department of Biology, City College of New York New York, NY, USA ; Department of Biology, The Graduate Center, City University of New York New York, NY, USA
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113
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O'Reilly LP, Benson JA, Cummings EE, Perlmutter DH, Silverman GA, Pak SC. Worming our way to novel drug discovery with the Caenorhabditis elegans proteostasis network, stress response and insulin-signaling pathways. Expert Opin Drug Discov 2014; 9:1021-32. [PMID: 24998976 DOI: 10.1517/17460441.2014.930125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Many human diseases result from a failure of a single protein to achieve the correct folding and tertiary conformation. These so-called 'conformational diseases' involve diverse proteins and distinctive cellular pathologies. They all engage the proteostasis network (PN), to varying degrees in an attempt to mange cellular stress and restore protein homeostasis. The insulin/insulin-like growth factor signaling (IIS) pathway is a master regulator of cellular stress response, which is implicated in regulating components of the PN. AREAS COVERED This review focuses on novel approaches to target conformational diseases. The authors discuss the evidence supporting the involvement of the IIS pathway in modulating the PN and regulating proteostasis in Caenorhabditis elegans. Furthermore, they review previous PN and IIS drug screens and explore the possibility of using C. elegans for whole organism-based drug discovery for modulators of IIS-proteostasis pathways. EXPERT OPINION An alternative approach to develop individualized therapy for each conformational disease is to modulate the global PN. The involvement of the IIS pathway in regulating longevity and response to a variety of stresses is well documented. Increasing data now provide evidence for the close association between the IIS and the PN pathways. The authors believe that high-throughput screening campaigns, which target the C. elegans IIS pathway, may identify drugs that are efficacious in treating numerous conformational diseases.
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Affiliation(s)
- Linda P O'Reilly
- University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC and Magee-Womens Hospital Research Institute, Department of Pediatrics , 4401 Penn Avenue, Rangos Room 7131, Pittsburgh, PA 15224 , USA +1 412 692 9457 ; +1 412 641 1844 ;
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114
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Spears W, Furgerson M, Sweetnam JM, Evans P, Gearing M, Fechheimer M, Furukawa R. Hirano bodies differentially modulate cell death induced by tau and the amyloid precursor protein intracellular domain. BMC Neurosci 2014; 15:74. [PMID: 24929931 PMCID: PMC4084581 DOI: 10.1186/1471-2202-15-74] [Citation(s) in RCA: 10] [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: 04/07/2014] [Accepted: 06/06/2014] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Hirano bodies are actin-rich paracrystalline inclusions found in brains of patients with Alzheimer's disease (AD), frontotemporal dementia (FTD), and in normal aged individuals. Although studies of post-mortem brain tissue provide clues of etiology, the physiological function of Hirano bodies remains unknown. A cell culture model was utilized to study the interactions of mutant tau proteins, model Hirano bodies, and GSK3β in human astrocytoma cells. RESULTS Most tau variants showed co-localization with model Hirano bodies. Cosedimentation assays revealed this interaction may be direct, as recombinant purified forms of tau are all capable of binding F-actin. Model Hirano bodies had no effect or enhanced cell death induced by tau in the absence of amyloid precursor protein intracellular domain (AICD). In the presence of AICD and tau, synergistic cell death was observed in most cases, and model Hirano bodies decreased this synergistic cell death, except for forms of tau that caused significant cell death in the presence of Hirano bodies only. A role for the kinase GSK3β is suggested by the finding that a dominant negative form of GSK3β reduces this synergistic cell death. A subset of Hirano bodies in brain tissue of both Alzheimer's disease and normal aged individuals was found to contain tau, with some Hirano bodies in Alzheimer's disease brains containing hyperphosphorylated tau. CONCLUSION The results demonstrate a complex interaction between tau and AICD involving activation of GSK3β in promoting cell death, and the ability of Hirano bodies to modulate this process.
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Affiliation(s)
- William Spears
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Matthew Furgerson
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | | | - Parker Evans
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Marla Gearing
- Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Marcus Fechheimer
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Ruth Furukawa
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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115
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Tenreiro S, Eckermann K, Outeiro TF. Protein phosphorylation in neurodegeneration: friend or foe? Front Mol Neurosci 2014; 7:42. [PMID: 24860424 PMCID: PMC4026737 DOI: 10.3389/fnmol.2014.00042] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 04/22/2014] [Indexed: 12/15/2022] Open
Abstract
Protein misfolding and aggregation is a common hallmark in neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), and fronto-temporal dementia (FTD). In these disorders, the misfolding and aggregation of specific proteins occurs alongside neuronal degeneration in somewhat specific brain areas, depending on the disorder and the stage of the disease. However, we still do not fully understand the mechanisms governing protein aggregation, and whether this constitutes a protective or detrimental process. In PD, alpha-synuclein (aSyn) forms protein aggregates, known as Lewy bodies, and is phosphorylated at serine 129. Other residues have also been shown to be phosphorylated, but the significance of phosphorylation in the biology and pathophysiology of the protein is still controversial. In AD and in FTD, hyperphosphorylation of tau protein causes its misfolding and aggregation. Again, our understanding of the precise consequences of tau phosphorylation in the biology and pathophysiology of the protein is still limited. Through the use of a variety of model organisms and technical approaches, we are now gaining stronger insight into the effects of phosphorylation in the behavior of these proteins. In this review, we cover recent findings in the field and discuss how targeting phosphorylation events might be used for therapeutic intervention in these devastating diseases of the nervous system.
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Affiliation(s)
- Sandra Tenreiro
- Cell and Molecular Neuroscience Unit, Instituto de Medicina Molecular Lisboa, Portugal
| | - Katrin Eckermann
- Department of Neurology, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen Göttingen, Germany
| | - Tiago F Outeiro
- Cell and Molecular Neuroscience Unit, Instituto de Medicina Molecular Lisboa, Portugal ; Instituto de Fisiologia, Faculdade de Medicina da Universidade de Lisboa Lisboa, Portugal ; Department of NeuroDegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen Göttingen, Germany
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116
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Xie C, Miyasaka T, Yoshimura S, Hatsuta H, Yoshina S, Kage-Nakadai E, Mitani S, Murayama S, Ihara Y. The homologous carboxyl-terminal domains of microtubule-associated protein 2 and TAU induce neuronal dysfunction and have differential fates in the evolution of neurofibrillary tangles. PLoS One 2014; 9:e89796. [PMID: 24587039 PMCID: PMC3934940 DOI: 10.1371/journal.pone.0089796] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 01/25/2014] [Indexed: 01/11/2023] Open
Abstract
Microtubule-associated protein 2 (MAP2) and Tau are abundant neuronal microtubule-associated proteins. Both proteins have highly homologous carboxyl-terminal sequences that function as microtubule-binding domains. Whereas Tau is widely accepted as a pathoetiological factor in human tauopathies, including Alzheimer's disease (AD), it is not known whether there is a relationship between MAP2 and tauopathy. To better understand the pathological roles of MAP2 and Tau, we compared their behaviors in transgenic Caenorhabditis elegans in which MAP2 or Tau was expressed pan-neuronally. Both MAP2 and Tau elicited severe neuronal dysfunction and neuritic abnormalities, despite the absence of detergent-insoluble aggregates in worm neurons. Biochemical analysis revealed that the expressed MAP2 or Tau in worms was highly phosphorylated and did not bind to microtubules. Newly raised antibodies to MAP2 that effectively distinguished between the highly homologous carboxyl-terminal sequences of MAP2 and Tau showed that MAP2 was not involved in the growth process of neurofibrillary tangles in the AD brain. These results indicate that Tau and MAP2 have different fates in the inclusion formation and raise the possibility that MAP2 plays a significant role in neurotoxicity in the AD brain despite the absence of MAP2-aggregates.
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Affiliation(s)
- Ce Xie
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe-shi, Kyoto, Japan
| | - Tomohiro Miyasaka
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe-shi, Kyoto, Japan
| | - Satomi Yoshimura
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe-shi, Kyoto, Japan
| | - Hiroyuki Hatsuta
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan
| | - Sawako Yoshina
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Eriko Kage-Nakadai
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Shohei Mitani
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Shigeo Murayama
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan
| | - Yasuo Ihara
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe-shi, Kyoto, Japan
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117
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Stack C, Jainuddin S, Elipenahli C, Gerges M, Starkova N, Starkov AA, Jové M, Portero-Otin M, Launay N, Pujol A, Kaidery NA, Thomas B, Tampellini D, Beal MF, Dumont M. Methylene blue upregulates Nrf2/ARE genes and prevents tau-related neurotoxicity. Hum Mol Genet 2014; 23:3716-32. [PMID: 24556215 DOI: 10.1093/hmg/ddu080] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Methylene blue (MB, methylthioninium chloride) is a phenothiazine that crosses the blood brain barrier and acts as a redox cycler. Among its beneficial properties are its abilities to act as an antioxidant, to reduce tau protein aggregation and to improve energy metabolism. These actions are of particular interest for the treatment of neurodegenerative diseases with tau protein aggregates known as tauopathies. The present study examined the effects of MB in the P301S mouse model of tauopathy. Both 4 mg/kg MB (low dose) and 40 mg/kg MB (high dose) were administered in the diet ad libitum from 1 to 10 months of age. We assessed behavior, tau pathology, oxidative damage, inflammation and numbers of mitochondria. MB improved the behavioral abnormalities and reduced tau pathology, inflammation and oxidative damage in the P301S mice. These beneficial effects were associated with increased expression of genes regulated by NF-E2-related factor 2 (Nrf2)/antioxidant response element (ARE), which play an important role in antioxidant defenses, preventing protein aggregation, and reducing inflammation. The activation of Nrf2/ARE genes is neuroprotective in other transgenic mouse models of neurodegenerative diseases and it appears to be an important mediator of the neuroprotective effects of MB in P301S mice. Moreover, we used Nrf2 knock out fibroblasts to show that the upregulation of Nrf2/ARE genes by MB is Nrf2 dependent and not due to secondary effects of the compound. These findings provide further evidence that MB has important neuroprotective effects that may be beneficial in the treatment of human neurodegenerative diseases with tau pathology.
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Affiliation(s)
- Cliona Stack
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Shari Jainuddin
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Ceyhan Elipenahli
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Meri Gerges
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Natalia Starkova
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Anatoly A Starkov
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Mariona Jové
- Department de Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Spain
| | | | - Nathalie Launay
- Neurometabolic Diseases Laboratory-IDIBELL, Hospital Duran i Reynals, 08908 L'Hospitalet de Llobregat, Barcelona, Spain, CIBERER, Spanish Network for Rare Diseases, ISCIII, Spain
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory-IDIBELL, Hospital Duran i Reynals, 08908 L'Hospitalet de Llobregat, Barcelona, Spain, CIBERER, Spanish Network for Rare Diseases, ISCIII, Spain, ICREA, Catalan Institution for Research and Advanced Studies, Spain
| | - Navneet Ammal Kaidery
- Department of Pharmacology and Toxicology and Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Bobby Thomas
- Department of Pharmacology and Toxicology and Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Davide Tampellini
- Hospital Kremlin Bicêtre, UMR 788, Institut National de la Santé et de la Recherche Médicale (INSERM), Université Paris Sud, Le Kremlin Bicêtre, France and
| | - M Flint Beal
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Magali Dumont
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA, IHU-A-ICM, Hospital Pitié-Salpêtrière, 75013 Paris, France
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118
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Ballatore C, Smith AB, Lee VMY, Trojanowski JQ, Brunden KR. Aminothienopyridazines as imaging probes of tau pathology: a patent evaluation of WO2013090497. Expert Opin Ther Pat 2014; 24:355-60. [PMID: 24387030 DOI: 10.1517/13543776.2014.871526] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Small-molecule ligands, amenable to positron emission tomography (PET) imaging of different types of neurodegenerative disease-associated amyloid deposits in the CNS of living patients, hold considerable promise for diagnostic purposes, as well as for monitoring disease progression and the effectiveness of treatments. The patent entitled 'Heterocyclic Compounds as Imaging Probes of Tau Pathology' (WO2013090497) discloses the identification of a novel class of tau imaging agents, the aminothienopyridazines. Selected compounds from this class are described that can stain selectively tau pathology in brain tissue sections. Moreover, examples of this class of compounds exhibit absorption, distribution, metabolism, excretion and pharmacokinetics (ADME-PK) properties that are appropriate for CNS PET ligands.
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Affiliation(s)
- Carlo Ballatore
- University of Pennsylvania, Perelman School of Medicine, Center for Neurodegenerative Disease Research , 3600 Spruce Street, Philadelphia, PA 19104-6323 , USA
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119
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Abstract
Similar to other organisms, necrotic cell death in the nematode Caenorhabditis elegans is manifested as the catastrophic collapse of cellular homeostasis, in response to overwhelming stress that is inflicted either in the form of extreme environmental stimuli or by intrinsic insults such as the expression of proteins carrying deleterious mutations. Remarkably, necrotic cell death in C. elegans and pathological cell death in humans share multiple fundamental features and mechanistic aspects. Therefore, mechanisms mediating necrosis are also conserved across the evolutionary spectrum and render the worm a versatile tool, with the capacity to facilitate studies of human pathologies. Here, we overview necrotic paradigms that have been characterized in the nematode and outline the cellular and molecular mechanisms that mediate this mode of cell demise. In addition, we discuss experimental approaches that utilize C. elegans to elucidate the molecular underpinnings of devastating human disorders that entail necrosis.
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Affiliation(s)
- Vassiliki Nikoletopoulou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece.
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120
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Li J, Le W. Modeling neurodegenerative diseases in Caenorhabditis elegans. Exp Neurol 2013; 250:94-103. [PMID: 24095843 DOI: 10.1016/j.expneurol.2013.09.024] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 09/18/2013] [Accepted: 09/21/2013] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases which include Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Huntington disease (HD), and others are becoming an increasing threat to human health worldwide. The degeneration and death of certain specific groups of neurons are the hallmarks of these diseases. Despite the research progress in identification of several disease-related genes, the mechanisms underlying the neurodegeneration in these diseases remain unclear. Given the molecular conservation in neuronal signaling between Caenorhabditis elegans and vertebrates, an increasing number of research scientists have used the nematode to study this group of diseases. This review paper will focus on the model system that has been established in C. elegans to investigate the pathogenetic roles of those reported disease-related genes in AD, PD, ALS, HD and others. The progress in C. elegans provides useful information of the genetic interactions and molecular pathways that are critical in the disease process, and may help better our understanding of the disease mechanisms and search for new therapeutics for these devastating diseases.
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Affiliation(s)
- Jia Li
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, P.R. China
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121
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Chua JJE, Jahn R, Klopfenstein DR. Managing intracellular transport. WORM 2013; 2:e21564. [PMID: 24058857 PMCID: PMC3670458 DOI: 10.4161/worm.21564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 07/18/2012] [Accepted: 07/20/2012] [Indexed: 11/19/2022]
Abstract
Formation and normal function of neuronal synapses are intimately dependent on the delivery to and removal of biological materials from synapses by the intracellular transport machinery. Indeed, defects in intracellular transport contribute to the development and aggravation of neurodegenerative disorders. Despite its importance, regulatory mechanisms underlying this machinery remain poorly defined. We recently uncovered a phosphorylation-regulated mechanism that controls FEZ1-mediated Kinesin-1-based delivery of Stx1 into neuronal axons. Using C. elegans as a model organism to investigate transport defects, we show that FEZ1 mutations resulted in abnormal Stx1 aggregation in neuronal cell bodies and axons. This phenomenon closely resembles transport defects observed in neurodegenerative disorders. Importantly, diminished transport due to mutations of FEZ1 and Kinesin-1 were concomitant with increased accumulation of autophagosomes. Here, we discuss the significance of our findings in a broader context in relation to regulation of Kinesin-mediated transport and neurodegenerative disorders.
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Affiliation(s)
- John J E Chua
- Department of Neurobiology; Max-Planck-Institute for Biophysical Chemistry; Germany
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122
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Eckert A, Nisbet R, Grimm A, Götz J. March separate, strike together--role of phosphorylated TAU in mitochondrial dysfunction in Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2013; 1842:1258-66. [PMID: 24051203 DOI: 10.1016/j.bbadis.2013.08.013] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 08/08/2013] [Accepted: 08/12/2013] [Indexed: 12/17/2022]
Abstract
The energy demand and calcium buffering requirements of the brain are met by the high number of mitochondria in neurons and in these, especially at the synapses. Mitochondria are the major producer of reactive oxygen species (ROS); at the same time, they are damaged by ROS that are induced by abnormal protein aggregates that characterize human neurodegenerative diseases such as Alzheimer's disease (AD). Because synaptic mitochondria are long-lived, any damage exerted by these aggregates impacts severely on neuronal function. Here we review how increased TAU, a defining feature of AD and related tauopathies, impairs mitochondrial function by following the principle: 'March separate, strike together!' In the presence of amyloid-β, TAU's toxicity is augmented suggesting synergistic pathomechanisms. In order to restore mitochondrial functions in neurodegeneration as a means of therapeutic intervention it will be important to integrate the various aspects of dysfunction and get a handle on targeting distinct cell types and subcellular compartments.
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Affiliation(s)
- Anne Eckert
- Neurobiology Laboratory, Psychiatric University Clinics Basel, University of Basel, Switzerland
| | - Rebecca Nisbet
- Centre for Ageing Dementia Research (CADR), Queensland Brain Institute (QBI), The University of Queensland, Australia
| | - Amandine Grimm
- Neurobiology Laboratory, Psychiatric University Clinics Basel, University of Basel, Switzerland
| | - Jürgen Götz
- Centre for Ageing Dementia Research (CADR), Queensland Brain Institute (QBI), The University of Queensland, Australia.
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123
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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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124
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Cowan CM, Mudher A. Are tau aggregates toxic or protective in tauopathies? Front Neurol 2013; 4:114. [PMID: 23964266 PMCID: PMC3741634 DOI: 10.3389/fneur.2013.00114] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 07/29/2013] [Indexed: 11/13/2022] Open
Abstract
Aggregation of highly phosphorylated tau into aggregated forms such as filaments and neurofibrillary tangles is one of the defining pathological hallmarks of Alzheimer's disease and other tauopathies. Hence therapeutic strategies have focused on inhibition of tau phosphorylation or disruption of aggregation. However, animal models imply that tau-mediated dysfunction and toxicity do not require aggregation but instead are caused by soluble hyper-phosphorylated tau. Over the years, our findings from a Drosophila model of tauopathy have reinforced this. We have shown that highly phosphorylated wild-type human tau causes behavioral deficits resulting from synaptic dysfunction, axonal transport disruption, and cytoskeletal destabilization in vivo. These deficits are evident in the absence of neuronal death or filament/tangle formation. Unsurprisingly, both pharmacological and genetic inhibition of GSK-3β rescue these tau phenotypes. However, GSK-3β inhibition also unexpectedly increases tau protein levels, and produces insoluble granular tau oligomers. As well as underlining the growing consensus that tau toxicity is mediated by a highly phosphorylated soluble tau species, our findings further show that not all insoluble tau aggregates are toxic. Some tau aggregates, in particular tau oligomers, are non-toxic, and may even be protective against tau toxicity in vivo. This has serious implications for emerging therapeutic strategies to dissolve tau aggregates, which might be ineffective or even counter-productive. In light of this, it is imperative to identify the key toxic tau species and to understand how it mediates dysfunction and degeneration so that the effective disease-modifying therapies can be developed.
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Affiliation(s)
- Catherine M Cowan
- Centre for Biological Sciences, University of Southampton , Southampton , UK
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125
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Yoshiyama Y, Lee VMY, Trojanowski JQ. Therapeutic strategies for tau mediated neurodegeneration. J Neurol Neurosurg Psychiatry 2013; 84:784-95. [PMID: 23085937 PMCID: PMC3912572 DOI: 10.1136/jnnp-2012-303144] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Based on the amyloid hypothesis, controlling β-amyloid protein (Aβ) accumulation is supposed to suppress downstream pathological events, tau accumulation, neurodegeneration and cognitive decline. However, in recent clinical trials, Aβ removal or reducing Aβ production has shown limited efficacy. Moreover, while active immunisation with Aβ resulted in the clearance of Aβ, it did not prevent tau pathology or neurodegeneration. This prompts the concern that it might be too late to employ Aβ targeting therapies once tau mediated neurodegeneration has occurred. Therefore, it is timely and very important to develop tau directed therapies. The pathomechanisms of tau mediated neurodegeneration are unclear but hyperphosphorylation, oligomerisation, fibrillisation and propagation of tau pathology have been proposed as the likely pathological processes that induce loss of function or gain of toxic function of tau, causing neurodegeneration. Here we review the strategies for tau directed treatments based on recent progress in research on tau and our understanding of the pathomechanisms of tau mediated neurodegeneration.
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Affiliation(s)
- Yasumasa Yoshiyama
- Department of Neurology, Chiba East National Hospital, 673 Nitona, Chuo Ward, Chiba, Chiba 260-8712, Japan.
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126
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Bulic B, Pickhardt M, Mandelkow E. Progress and developments in tau aggregation inhibitors for Alzheimer disease. J Med Chem 2013; 56:4135-55. [PMID: 23484434 DOI: 10.1021/jm3017317] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pharmacological approaches directed toward Alzheimer disease are diversifying in parallel with a growing number of promising targets. Investigations on the microtubule-associated protein tau yielded innovative targets backed by recent findings about the central role of tau in numerous neurodegenerative diseases. In this review, we summarize the recent evolution in the development of nonpeptidic small molecules tau aggregation inhibitors (TAGIs) and their advancement toward clinical trials. The compounds are classified according to their chemical structures, providing correlative insights into their pharmacology. Overall, shared structure-activity traits are emerging, as well as specific binding modes related to their ability to engage in hydrogen bonding. Medicinal chemistry efforts on TAGIs together with encouraging in vivo data argue for successful translation to the clinic.
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Affiliation(s)
- Bruno Bulic
- Laboratory of Organic Synthesis of Functional Systems, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany.
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127
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Götz J, Xia D, Leinenga G, Chew YL, Nicholas HR. What Renders TAU Toxic. Front Neurol 2013; 4:72. [PMID: 23772223 PMCID: PMC3677143 DOI: 10.3389/fneur.2013.00072] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 05/28/2013] [Indexed: 12/21/2022] Open
Abstract
TAU is a microtubule-associated protein that under pathological conditions such as Alzheimer's disease (AD) forms insoluble, filamentous aggregates. When 20 years after TAU's discovery the first TAU transgenic mouse models were established, one declared goal that was achieved was the modeling of authentic TAU aggregate formation in the form of neurofibrillary tangles. However, as we review here, it has become increasingly clear that TAU causes damage much before these filamentous aggregates develop. In fact, because TAU is a scaffolding protein, increased levels and an altered subcellular localization (due to an increased insolubility and impaired clearance) result in the interaction of TAU with cellular proteins with which it would otherwise either not interact or do so to a lesser degree, thereby impairing their physiological functions. We specifically discuss the non-axonal localization of TAU, the role phosphorylation has in TAU toxicity and how TAU impairs mitochondrial functions. A major emphasis is on what we have learned from the four available TAU knock-out models in mice, and the knock-out of the TAU/MAP2 homolog PTL-1 in worms. It has been proposed that in human pathological conditions such as AD, a rare toxic TAU species exists which needs to be specifically removed to abrogate TAU's toxicity and restore neuronal functions. However, what is toxic in one context may not be in another, and simply reducing, but not fully abolishing TAU levels may be sufficient to abrogate TAU toxicity.
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Affiliation(s)
- Jürgen Götz
- Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Sydney Medical School, Brain and Mind Research Institute, University of Sydney, Sydney, NSW, Australia
| | - Di Xia
- Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Gerhard Leinenga
- Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Yee Lian Chew
- School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia
| | - Hannah R. Nicholas
- School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia
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128
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Using C. elegans to Decipher the Cellular and Molecular Mechanisms Underlying Neurodevelopmental Disorders. Mol Neurobiol 2013; 48:465-89. [DOI: 10.1007/s12035-013-8434-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 02/26/2013] [Indexed: 10/27/2022]
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129
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Akoury E, Pickhardt M, Gajda M, Biernat J, Mandelkow E, Zweckstetter M. Mechanistic basis of phenothiazine-driven inhibition of Tau aggregation. Angew Chem Int Ed Engl 2013; 52:3511-5. [PMID: 23401175 DOI: 10.1002/anie.201208290] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 12/14/2012] [Indexed: 01/05/2023]
Affiliation(s)
- Elias Akoury
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
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130
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Akoury E, Pickhardt M, Gajda M, Biernat J, Mandelkow E, Zweckstetter M. Mechanismus der Phenothiazin-induzierten Hemmung der Tau-Aggregation. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201208290] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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131
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Affiliation(s)
- Monte S Willis
- McAllister Heart Institute, and Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, USA
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132
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Mondal S, Ahlawat S, Koushika SP. Simple microfluidic devices for in vivo imaging of C. elegans, Drosophila and zebrafish. J Vis Exp 2012:3780. [PMID: 23051668 DOI: 10.3791/3780] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Micro fabricated fluidic devices provide an accessible micro-environment for in vivo studies on small organisms. Simple fabrication processes are available for microfluidic devices using soft lithography techniques. Microfluidic devices have been used for sub-cellular imaging, in vivo laser microsurgery and cellular imaging. In vivo imaging requires immobilization of organisms. This has been achieved using suction, tapered channels, deformable membranes, suction with additional cooling anesthetic gas, temperature sensitive gels, cyanoacrylate glue and anesthetics such as levamisole. Commonly used anesthetics influence synaptic transmission and are known to have detrimental effects on sub-cellular neuronal transport. In this study we demonstrate a membrane based poly-dimethyl-siloxane (PDMS) device that allows anesthetic free immobilization of intact genetic model organisms such as Caenorhabditis elegans (C. elegans), Drosophila larvae and zebrafish larvae. These model organisms are suitable for in vivo studies in microfluidic devices because of their small diameters and optically transparent or translucent bodies. Body diameters range from -10 μm to -800 μm for early larval stages of C. elegans and zebrafish larvae and require microfluidic devices of different sizes to achieve complete immobilization for high resolution time-lapse imaging. These organisms are immobilized using pressure applied by compressed nitrogen gas through a liquid column and imaged using an inverted microscope. Animals released from the trap return to normal locomotion within 10 min. We demonstrate four applications of time-lapse imaging in C. elegans namely, imaging mitochondrial transport in neurons, pre-synaptic vesicle transport in a transport-defective mutant, glutamate receptor transport and Q neuroblast cell division. Data obtained from such movies show that microfluidic immobilization is a useful and accurate means of acquiring in vivo data of cellular and sub-cellular events when compared to anesthetized animals (Figure 1J and 3C-F). Device dimensions were altered to allow time-lapse imaging of different stages of C. elegans, first instar Drosophila larvae and zebrafish larvae. Transport of vesicles marked with synaptotagmin tagged with GFP (syt.eGFP) in sensory neurons shows directed motion of synaptic vesicle markers expressed in cholinergic sensory neurons in intact first instar Drosophila larvae. A similar device has been used to carry out time-lapse imaging of heartbeat in -30 hr post fertilization (hpf) zebrafish larvae. These data show that the simple devices we have developed can be applied to a variety of model systems to study several cell biological and developmental phenomena in vivo.
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