1
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Diaz Escarcega R, Murambadoro K, Valencia R, Moruno-Manchon JF, Furr Stimming EE, Jung SY, Tsvetkov AS. Sphingosine kinase 2 regulates protein ubiquitination networks in neurons. Mol Cell Neurosci 2024; 130:103948. [PMID: 38909878 DOI: 10.1016/j.mcn.2024.103948] [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: 01/15/2024] [Revised: 05/31/2024] [Accepted: 06/17/2024] [Indexed: 06/25/2024] Open
Abstract
Two sphingosine kinase isoforms, sphingosine kinase 1 (SPHK1) and sphingosine kinase 2 (SPHK2), synthesize the lipid sphingosine-1-phosphate (S1P) by phosphorylating sphingosine. SPHK1 is a cytoplasmic kinase, and SPHK2 is localized to the nucleus and other organelles. In the cytoplasm, the SPHK1/S1P pathway modulates autophagy and protein ubiquitination, among other processes. In the nucleus, the SPHK2/S1P pathway regulates transcription. Here, we hypothesized that the SPHK2/S1P pathway governs protein ubiquitination in neurons. We found that ectopic expression of SPHK2 increases ubiquitinated substrate levels in cultured neurons and pharmacologically inhibiting SPHK2 decreases protein ubiquitination. With mass spectrometry, we discovered that inhibiting SPHK2 affects lipid and synaptic protein networks as well as a ubiquitin-dependent protein network. Several ubiquitin-conjugating and hydrolyzing proteins, such as the E3 ubiquitin-protein ligases HUWE1 and TRIP12, the E2 ubiquitin-conjugating enzyme UBE2Z, and the ubiquitin-specific proteases USP15 and USP30, were downregulated by SPHK2 inhibition. Using RNA sequencing, we found that inhibiting SPHK2 altered lipid and neuron-specific gene networks, among others. Genes that encode the corresponding proteins from the ubiquitin-dependent protein network that we discovered with mass spectrometry were not affected by inhibiting SPHK2, indicating that the SPHK2/S1P pathway regulates ubiquitination at the protein level. We also show that both SPHK2 and HUWE1 were upregulated in the striatum of a mouse model of Huntington's disease, the BACHD mice, indicating that our findings are relevant to neurodegenerative diseases. Our results identify SPHK2/S1P as a novel regulator of protein ubiquitination networks in neurons and provide a new target for developing therapies for neurodegenerative diseases.
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Affiliation(s)
- Rocio Diaz Escarcega
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX 77030, United States of America
| | - Karen Murambadoro
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX 77030, United States of America
| | - Ricardo Valencia
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX 77030, United States of America
| | - Jose Felix Moruno-Manchon
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX 77030, United States of America
| | - Erin E Furr Stimming
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX 77030, United States of America
| | - Sung Yun Jung
- Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX 77030, United States of America.
| | - Andrey S Tsvetkov
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX 77030, United States of America; The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, United States of America; UTHealth Consortium on Aging, the University of Texas McGovern Medical School, Houston, TX 77030, United States of America.
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2
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Jeong J, Usman M, Li Y, Zhou XZ, Lu KP. Pin1-Catalyzed Conformation Changes Regulate Protein Ubiquitination and Degradation. Cells 2024; 13:731. [PMID: 38727267 PMCID: PMC11083468 DOI: 10.3390/cells13090731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/12/2024] [Accepted: 04/14/2024] [Indexed: 05/13/2024] Open
Abstract
The unique prolyl isomerase Pin1 binds to and catalyzes cis-trans conformational changes of specific Ser/Thr-Pro motifs after phosphorylation, thereby playing a pivotal role in regulating the structure and function of its protein substrates. In particular, Pin1 activity regulates the affinity of a substrate for E3 ubiquitin ligases, thereby modulating the turnover of a subset of proteins and coordinating their activities after phosphorylation in both physiological and disease states. In this review, we highlight recent advancements in Pin1-regulated ubiquitination in the context of cancer and neurodegenerative disease. Specifically, Pin1 promotes cancer progression by increasing the stabilities of numerous oncoproteins and decreasing the stabilities of many tumor suppressors. Meanwhile, Pin1 plays a critical role in different neurodegenerative disorders via the regulation of protein turnover. Finally, we propose a novel therapeutic approach wherein the ubiquitin-proteasome system can be leveraged for therapy by targeting pathogenic intracellular targets for TRIM21-dependent degradation using stereospecific antibodies.
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Affiliation(s)
- Jessica Jeong
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
| | - Muhammad Usman
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
| | - Yitong Li
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
| | - Xiao Zhen Zhou
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Department of Pathology and Laboratory Medicine, and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada
- Lawson Health Research Institute, Western University, London, ON N6C 2R5, Canada
| | - Kun Ping Lu
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
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3
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Yuan R, Hahn Y, Stempel MH, Sidibe DK, Laxton O, Chen J, Kulkarni A, Maday S. Proteasomal inhibition preferentially stimulates lysosome activity relative to autophagic flux in primary astrocytes. Autophagy 2023; 19:570-596. [PMID: 35722992 PMCID: PMC9851260 DOI: 10.1080/15548627.2022.2084884] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 05/23/2022] [Accepted: 05/26/2022] [Indexed: 01/22/2023] Open
Abstract
Neurons and astrocytes face unique demands on their proteome to enable proper function and survival of the nervous system. Consequently, both cell types are critically dependent on robust quality control pathways such as macroautophagy (hereafter referred to as autophagy) and the ubiquitin-proteasome system (UPS). We previously reported that autophagy is differentially regulated in astrocytes and neurons in the context of metabolic stress, but less is understood in the context of proteotoxic stress induced by inhibition of the UPS. Dysfunction of the proteasome or autophagy has been linked to the progression of various neurodegenerative diseases. Therefore, in this study, we explored the connection between autophagy and the proteasome in primary astrocytes and neurons. Prior studies largely in non-neural models report a compensatory relationship whereby inhibition of the UPS stimulates autophagy. To our surprise, inhibition of the proteasome did not robustly upregulate autophagy in astrocytes or neurons. In fact, the effects on autophagy are modest particularly in comparison to paradigms of metabolic stress. Rather, we find that UPS inhibition in astrocytes induces formation of Ub-positive aggregates that harbor the selective autophagy receptor, SQSTM1/p62, but these structures were not productive substrates for autophagy. By contrast, we observed a significant increase in lysosomal degradation in astrocytes in response to UPS inhibition, but this stimulation was not sufficient to reduce total SQSTM1 levels. Last, UPS inhibition was more toxic in neurons compared to astrocytes, suggesting a cell type-specific vulnerability to proteotoxic stress.Abbreviations: Baf A1: bafilomycin A1; CQ: chloroquine; Epox: epoxomicin; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; p-ULK1: phospho-ULK1; SQSTM1/p62: sequestosome 1; Ub: ubiquitin; ULK1: unc-51 like kinase 1; UPS: ubiquitin-proteasome system.
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Affiliation(s)
- Ruiyi Yuan
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Younghee Hahn
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Max H. Stempel
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - David K. Sidibe
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Olivia Laxton
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Jessica Chen
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Aditi Kulkarni
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Sandra Maday
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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4
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Bhat SA, Ahamad S, Dar NJ, Siddique YH, Nazir A. The Emerging Landscape of Natural Small-molecule Therapeutics for Huntington's Disease. Curr Neuropharmacol 2023; 21:867-889. [PMID: 36797612 PMCID: PMC10227909 DOI: 10.2174/1570159x21666230216104621] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/12/2022] [Accepted: 11/18/2022] [Indexed: 02/18/2023] Open
Abstract
Huntington's disease (HD) is a rare and fatal neurodegenerative disorder with no diseasemodifying therapeutics. HD is characterized by extensive neuronal loss and is caused by the inherited expansion of the huntingtin (HTT) gene that encodes a toxic mutant HTT (mHTT) protein having expanded polyglutamine (polyQ) residues. Current HD therapeutics only offer symptomatic relief. In fact, Food and Drug Administration (FDA) approved two synthetic small-molecule VMAT2 inhibitors, tetrabenazine (1) and deutetrabenazine (2), for managing HD chorea and various other diseases in clinical trials. Therefore, the landscape of drug discovery programs for HD is evolving to discover disease- modifying HD therapeutics. Likewise, numerous natural products are being evaluated at different stages of clinical development and have shown the potential to ameliorate HD pathology. The inherent anti-inflammatory and antioxidant properties of natural products mitigate the mHTT-induced oxidative stress and neuroinflammation, improve mitochondrial functions, and augment the anti-apoptotic and pro-autophagic mechanisms for increased survival of neurons in HD. In this review, we have discussed HD pathogenesis and summarized the anti-HD clinical and pre-clinical natural products, focusing on their therapeutic effects and neuroprotective mechanism/s.
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Affiliation(s)
| | - Shakir Ahamad
- Department of Chemistry, Aligarh Muslim University, Aligarh, U.P., India
| | - Nawab John Dar
- School of Medicine, UT Health San Antonio, Texas, TX, USA
| | | | - Aamir Nazir
- Division of Neuroscience and Ageing Biology, CSIR-Central Drug Research Institute, Lucknow, U.P., India
- Academy of Scientific and Innovative Research, New Delhi, India
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5
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Merino M, Sequedo MD, Sánchez-Sánchez AV, Clares MP, García-España E, Vázquez-Manrique RP, Mullor JL. Mn(II) Quinoline Complex (4QMn) Restores Proteostasis and Reduces Toxicity in Experimental Models of Huntington's Disease. Int J Mol Sci 2022; 23:8936. [PMID: 36012207 PMCID: PMC9409211 DOI: 10.3390/ijms23168936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 12/04/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder, of the so-called minority diseases, due to its low prevalence. It is caused by an abnormally long track of glutamines (polyQs) in mutant huntingtin (mHtt), which makes the protein toxic and prone to aggregation. Many pathways of clearance of badly-folded proteins are disrupted in neurons of patients with HD. In this work, we show that one Mn(II) quinone complex (4QMn), designed to work as an artificial superoxide dismutase, is able to activate both the ubiquitin-proteasome system and the autophagy pathway in vitro and in vivo models of HD. Activation of these pathways degrades mHtt and other protein-containing polyQs, which restores proteostasis in these models. Hence, we propose 4QMn as a potential drug to develop a therapy to treat HD.
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Affiliation(s)
- Marián Merino
- Bionos Biotech SL, Biopolo Hospital La Fe, 46026 Valencia, Spain
| | - María Dolores Sequedo
- Laboratory of Molecular, Cellular and Genomic Biomedicine, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
| | | | - Mª Paz Clares
- Departamento de Química Orgánica e Inorgánica, Instituto de Ciencia Molecular, Universidad de Valencia, 46980 Valencia, Spain
| | - Enrique García-España
- Departamento de Química Orgánica e Inorgánica, Instituto de Ciencia Molecular, Universidad de Valencia, 46980 Valencia, Spain
| | - Rafael P. Vázquez-Manrique
- Laboratory of Molecular, Cellular and Genomic Biomedicine, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain
- Joint Unit for Rare Diseases IIS La Fe-CIPF, 46012 Valencia, Spain
| | - José L. Mullor
- Bionos Biotech SL, Biopolo Hospital La Fe, 46026 Valencia, Spain
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6
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Kaye J, Reisine T, Finkbeiner S. Huntington's disease iPSC models-using human patient cells to understand the pathology caused by expanded CAG repeats. Fac Rev 2022; 11:16. [PMID: 35865413 PMCID: PMC9264339 DOI: 10.12703/r/11-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
A major advance in the study of Huntington's disease (HD) has been the development of human disease models employing induced pluripotent stem cells (iPSCs) derived from patients with HD. Because iPSCs provide an unlimited source of cells and can be obtained from large numbers of HD patients, they are a uniquely valuable tool for investigating disease mechanisms and for discovering potential disease-modifying therapeutics. Here, we summarize some of the important findings in HD pathophysiology that have emerged from studies of patient-derived iPSC lines. Because they retain the genome and actual disease mutations of the patient, they provide a cell source to investigate genetic contributions to the disease. iPSCs provide advantages over other disease models. While iPSC-based technology erases some epigenetic marks, newly developed transdifferentiation methods now let us investigate epigenetic factors that control expression of mutant huntingtin (mHTT). Human HD iPSC lines allow us to investigate how endogenous levels of mHTT affect cell health, in contrast to other models that often rely on overexpressing the protein. iPSCs can be differentiated into neurons and other disease-related cells such as astrocytes from different brain regions to study brain regional differences in the disease process, as well as the cell-cell dependencies involved in HD-associated neurodegeneration. They also serve as a tissue source to investigate factors that impact CAG repeat instability, which is involved in regional differences in neurodegeneration in the HD brain. Human iPSC models can serve as a powerful model system to identify genetic modifiers that may impact disease onset, progression, and symptomatology, providing novel molecular targets for drug discovery.
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Affiliation(s)
- Julia Kaye
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, USA
| | - Terry Reisine
- Independent Scientific Consultant, Santa Cruz, CA, USA
| | - Steven Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, USA
- Taube/Koret Center for Neurodegenerative Disease Research, Gladstone Institutes, San Francisco, CA, USA
- Department of Neurology and Physiology, University of California, San Francisco, CA, USA
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7
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Baxi EG, Thompson T, Li J, Kaye JA, Lim RG, Wu J, Ramamoorthy D, Lima L, Vaibhav V, Matlock A, Frank A, Coyne AN, Landin B, Ornelas L, Mosmiller E, Thrower S, Farr SM, Panther L, Gomez E, Galvez E, Perez D, Meepe I, Lei S, Mandefro B, Trost H, Pinedo L, Banuelos MG, Liu C, Moran R, Garcia V, Workman M, Ho R, Wyman S, Roggenbuck J, Harms MB, Stocksdale J, Miramontes R, Wang K, Venkatraman V, Holewenski R, Sundararaman N, Pandey R, Manalo DM, Donde A, Huynh N, Adam M, Wassie BT, Vertudes E, Amirani N, Raja K, Thomas R, Hayes L, Lenail A, Cerezo A, Luppino S, Farrar A, Pothier L, Prina C, Morgan T, Jamil A, Heintzman S, Jockel-Balsarotti J, Karanja E, Markway J, McCallum M, Joslin B, Alibazoglu D, Kolb S, Ajroud-Driss S, Baloh R, Heitzman D, Miller T, Glass JD, Patel-Murray NL, Yu H, Sinani E, Vigneswaran P, Sherman AV, Ahmad O, Roy P, Beavers JC, Zeiler S, Krakauer JW, Agurto C, Cecchi G, Bellard M, Raghav Y, Sachs K, Ehrenberger T, Bruce E, Cudkowicz ME, Maragakis N, Norel R, Van Eyk JE, Finkbeiner S, Berry J, Sareen D, Thompson LM, Fraenkel E, Svendsen CN, Rothstein JD. Answer ALS, a large-scale resource for sporadic and familial ALS combining clinical and multi-omics data from induced pluripotent cell lines. Nat Neurosci 2022; 25:226-237. [PMID: 35115730 PMCID: PMC8825283 DOI: 10.1038/s41593-021-01006-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 12/16/2021] [Indexed: 12/13/2022]
Abstract
Answer ALS is a biological and clinical resource of patient-derived, induced pluripotent stem (iPS) cell lines, multi-omic data derived from iPS neurons and longitudinal clinical and smartphone data from over 1,000 patients with ALS. This resource provides population-level biological and clinical data that may be employed to identify clinical-molecular-biochemical subtypes of amyotrophic lateral sclerosis (ALS). A unique smartphone-based system was employed to collect deep clinical data, including fine motor activity, speech, breathing and linguistics/cognition. The iPS spinal neurons were blood derived from each patient and these cells underwent multi-omic analytics including whole-genome sequencing, RNA transcriptomics, ATAC-sequencing and proteomics. The intent of these data is for the generation of integrated clinical and biological signatures using bioinformatics, statistics and computational biology to establish patterns that may lead to a better understanding of the underlying mechanisms of disease, including subgroup identification. A web portal for open-source sharing of all data was developed for widespread community-based data analytics.
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Affiliation(s)
- Emily G Baxi
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Jonathan Li
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Julia A Kaye
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes and the Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Ryan G Lim
- UCI MIND, University of California, Irvine, CA, USA
| | - Jie Wu
- Department of Biological Chemistry, University of California, Irvine, CA, USA
| | - Divya Ramamoorthy
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Leandro Lima
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes and the Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Vineet Vaibhav
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Andrea Matlock
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Aaron Frank
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Alyssa N Coyne
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Barry Landin
- Computational Biology Center, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
| | - Loren Ornelas
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Elizabeth Mosmiller
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sara Thrower
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Lindsey Panther
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Emilda Gomez
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Erick Galvez
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Daniel Perez
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Imara Meepe
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Susan Lei
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Berhan Mandefro
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Hannah Trost
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Louis Pinedo
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Maria G Banuelos
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Chunyan Liu
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ruby Moran
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Veronica Garcia
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Michael Workman
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Richie Ho
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Stacia Wyman
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes and the Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | | | - Matthew B Harms
- Department of Neurology and Genetics, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Jennifer Stocksdale
- Department of Psychiatry and Human Behavior and Sue and Bill Gross Stem Cell Center, University of California, Irvine, CA, USA
| | | | - Keona Wang
- Department of Psychiatry and Human Behavior and Sue and Bill Gross Stem Cell Center, University of California, Irvine, CA, USA
| | - Vidya Venkatraman
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ronald Holewenski
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Niveda Sundararaman
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Rakhi Pandey
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Danica-Mae Manalo
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Aneesh Donde
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nhan Huynh
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Miriam Adam
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Brook T Wassie
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Edward Vertudes
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes and the Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Naufa Amirani
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes and the Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Krishna Raja
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes and the Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Reuben Thomas
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes and the Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Lindsey Hayes
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Alex Lenail
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Aianna Cerezo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sarah Luppino
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Alanna Farrar
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Lindsay Pothier
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Carolyn Prina
- Department of Neurology and Genetics, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | | | - Arish Jamil
- Department of Neurology, Emory University, Atlanta, GA, USA
| | - Sarah Heintzman
- Department of Neurology and Genetics, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | | | | | - Jesse Markway
- Department of Neurology, Washington University, St. Louis, MO, USA
| | - Molly McCallum
- Department of Neurology, Washington University, St. Louis, MO, USA
| | - Ben Joslin
- Department of Neurology, Northwestern University, Chicago, IL, USA
| | - Deniz Alibazoglu
- Department of Neurology, Northwestern University, Chicago, IL, USA
| | - Stephen Kolb
- Department of Neurology and Genetics, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | | | - Robert Baloh
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | | | - Tim Miller
- Department of Neurology, Washington University, St. Louis, MO, USA
| | | | | | - Hong Yu
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ervin Sinani
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Prasha Vigneswaran
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexander V Sherman
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Omar Ahmad
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Promit Roy
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jay C Beavers
- Microsoft Research, Microsoft Corporation, Redmond, WA, USA
| | - Steven Zeiler
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - John W Krakauer
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carla Agurto
- Computational Biology Center, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
| | - Guillermo Cecchi
- Computational Biology Center, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
| | - Mary Bellard
- Microsoft University Relations, Microsoft Corporation, Redmond, WA, USA
| | - Yogindra Raghav
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Karen Sachs
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Tobias Ehrenberger
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elizabeth Bruce
- Microsoft University Relations, Microsoft Corporation, Redmond, WA, USA
| | - Merit E Cudkowicz
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Nicholas Maragakis
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Raquel Norel
- Computational Biology Center, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
| | - Jennifer E Van Eyk
- Advanced Clinical Biosystems Research Institute, The Barbra Streisand Heart Center, The Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Steven Finkbeiner
- Center for Systems and Therapeutics and the Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes and the Departments of Neurology and Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - James Berry
- Department of Neurology, Healey Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Dhruv Sareen
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Leslie M Thompson
- UCI MIND, University of California, Irvine, CA, USA
- Department of Biological Chemistry, University of California, Irvine, CA, USA
- Department of Psychiatry and Human Behavior and Sue and Bill Gross Stem Cell Center, University of California, Irvine, CA, USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
| | - Ernest Fraenkel
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Clive N Svendsen
- Cedars-Sinai Biomanufacturing Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jeffrey D Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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8
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Threshold concentration and random collision determine the growth of the huntingtin inclusion from a stable core. Commun Biol 2021; 4:971. [PMID: 34400761 PMCID: PMC8368079 DOI: 10.1038/s42003-021-02460-z] [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: 01/04/2021] [Accepted: 07/14/2021] [Indexed: 12/03/2022] Open
Abstract
The processes underlying formation and growth of unfolded protein inclusions are relevant to neurodegenerative diseases but poorly characterized in living cells. In S. cerevisiae, inclusions formed by mutant huntingtin (mHtt) have some characteristics of biomolecular condensates but the physical nature and growth mechanisms of inclusion bodies remain unclear. We have probed the relationship between concentration and inclusion growth in vivo and find that growth of mHtt inclusions in living cells is triggered at a cytoplasmic threshold concentration, while reduction in cytoplasmic mHtt causes inclusions to shrink. The growth rate is consistent with incorporation of new material through collision and coalescence. A small remnant of the inclusion is relatively long-lasting, suggesting that it contains a core that is structurally distinct, and which may serve to nucleate it. These observations support a model in which aggregative particles are incorporated by random collision into a phase-separated condensate composed of a particle-rich mixture. Pei et al. explore the mechanism underlying growth of mutant huntingtin inclusions in yeast cells and show that growth occurs through random collision and incorporation of mutant huntingtin aggregates into a phase-separated condensate. They show that there is a small inner core which is structurally distinct, and may serve to nucleate the inclusion.
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9
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Proteasome Subunits Involved in Neurodegenerative Diseases. Arch Med Res 2020; 52:1-14. [PMID: 32962866 DOI: 10.1016/j.arcmed.2020.09.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 07/25/2020] [Accepted: 09/04/2020] [Indexed: 12/29/2022]
Abstract
The ubiquitin-proteasome system is the major pathway for the maintenance of protein homeostasis. Its inhibition causes accumulation of ubiquitinated proteins; this accumulation has been associated with several of the most common neurodegenerative diseases. Several genetic factors have been identified for most neurodegenerative diseases, however, most cases are considered idiopathic, thus making the study of the mechanisms of protein accumulation a relevant field of research. It is often mentioned that the biggest risk factor for neurodegenerative diseases is aging, and several groups have reported an age-related alteration of the expression of some of the 26S proteasome subunits and a reduction of its activity. Proteasome subunits interact with proteins that are known to accumulate in neurodegenerative diseases such as α-synuclein in Parkinson's, tau in Alzheimer's, and huntingtin in Huntington's diseases. These interactions have been explored for several years, but only until recently, we are beginning to understand them. In this review, we discuss the known interactions, the underlying patterns, and the phenotypes associated with the 26S proteasome subunits in the etiology and progression of neurodegenerative diseases where there is evidence of proteasome involvement. Special emphasis is made in reviewing proteasome subunits that interact with proteins known to have an age-related altered expression or to be involved in neurodegenerative diseases to explore key effectors that may trigger or augment their progression. Interestingly, while the causes of age-related reduction of some of the proteasome subunits are not known, there are specific relationships between the observed neurodegenerative disease and the affected proteasome subunits.
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10
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Loos B, Klionsky DJ, Du Toit A, Hofmeyr JHS. On the relevance of precision autophagy flux control in vivo - Points of departure for clinical translation. Autophagy 2020; 16:750-762. [PMID: 31679454 PMCID: PMC7138200 DOI: 10.1080/15548627.2019.1687211] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 10/11/2019] [Accepted: 10/28/2019] [Indexed: 12/14/2022] Open
Abstract
Macroautophagy (which we will call autophagy hereafter) is a critical intracellular bulk degradation system that is active at basal rates in eukaryotic cells. This process is embedded in the homeostasis of nutrient availability and cellular metabolic demands, degrading primarily long-lived proteins and specific organelles.. Autophagy is perturbed in many pathologies, and its manipulation to enhance or inhibit this pathway therapeutically has received considerable attention. Although better probes are being developed for a more precise readout of autophagic activity in vitro and increasingly in vivo, many questions remain. These center in particular around the accurate measurement of autophagic flux and its translation from the in vitro to the in vivo environment as well as its clinical application. In this review, we highlight key aspects that appear to contribute to stumbling blocks on the road toward clinical translation and discuss points of departure for reaching some of the desired goals. We discuss techniques that are well aligned with achieving desirable spatiotemporal resolution to gather data on autophagic flux in a multi-scale fashion, to better apply the existing tools that are based on single-cell analysis and to use them in the living organism. We assess how current techniques may be used for the establishment of autophagic flux standards or reference points and consider strategies for a conceptual approach on titrating autophagy inducers based on their effect on autophagic flux . Finally, we discuss potential solutions for inherent controls for autophagy analysis, so as to better discern systemic and tissue-specific autophagic flux in future clinical applications.Abbreviations: GFP: Green fluorescent protein; J: Flux; MAP1LC3/LC3: Microtubule-associated protein 1 light chain 3; nA: Number of autophagosomes; TEM: Transmission electron microscopy; τ: Transition time.
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Affiliation(s)
- Ben Loos
- Department of Physiological Sciences, Faculty of Natural Sciences, University of Stellenbosch, Stellenbosch, South Africa
| | - Daniel J. Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, USA
| | - Andre Du Toit
- Department of Biochemistry, Faculty of Natural Sciences, University of Stellenbosch, Stellenbosch, South Africa
| | - Jan-Hendrik S. Hofmeyr
- Department of Biochemistry, Faculty of Natural Sciences, University of Stellenbosch, Stellenbosch, South Africa
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11
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Rai SN, Singh BK, Rathore AS, Zahra W, Keswani C, Birla H, Singh SS, Dilnashin H, Singh SP. Quality Control in Huntington's Disease: a Therapeutic Target. Neurotox Res 2019; 36:612-626. [PMID: 31297710 DOI: 10.1007/s12640-019-00087-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 12/19/2022]
Abstract
Huntington's disease (HD) is a fatal autosomal dominantly inherited brain disease caused by excessively expanded CAG repeats in gene which encodes huntingtin protein. These abnormally encoded huntingtin proteins and their truncated fragments result in disruption of cellular quality mechanism ultimately triggering neuronal death. Despite great efforts, a potential causative agent leading to genetic mutation in HTT, manifesting the neurons more prone to oxidative stress, cellular inflammation, energy depletion and apoptotic death, has not been established yet. Current scenario concentrates on symptomatic pathologies to improvise the disease progression and to better the survival. Most of the therapeutic developments have been converged to rescue the protein homeostasis. In HD, abnormal expansion of glutamine repeats in the protein huntingtin leads to toxic aggregation of huntingtin which in turn impairs the quality control mechanism of cells through damaging the machineries involved in removal of aggregated abnormal protein. Therapeutic approaches to improve the efficiency of aggregate clearance through quality control mechanisms involve protein folding machineries such as chaperones and protein degradation machineries such as proteasome and autophagy. Also, to reduce protein aggregation by enhancing proper folding, to degrade and eliminate the aggregates are suggested to negatively regulate the HD progression associated with the disruption of protein homeostasis. This review focuses on the collection of therapeutic strategies targeting enhancement of protein quality control activity to delay the HD pathogenesis.
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Affiliation(s)
- Sachchida Nand Rai
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Brijesh Kumar Singh
- Department of Pathology and Cell Biology, Columbia University Medical Centre, Columbia University, New York, NY, 10032, USA
| | - Aaina Singh Rathore
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Walia Zahra
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Chetan Keswani
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Hareram Birla
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Saumitra Sen Singh
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Hagera Dilnashin
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Surya Pratap Singh
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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12
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Soares TR, Reis SD, Pinho BR, Duchen MR, Oliveira JMA. Targeting the proteostasis network in Huntington's disease. Ageing Res Rev 2019; 49:92-103. [PMID: 30502498 PMCID: PMC6320389 DOI: 10.1016/j.arr.2018.11.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 12/31/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a polyglutamine expansion mutation in the huntingtin protein. Expansions above 40 polyglutamine repeats are invariably fatal, following a symptomatic period characterised by choreiform movements, behavioural abnormalities, and cognitive decline. While mutant huntingtin (mHtt) is widely expressed from early life, most patients with HD present in mid-adulthood, highlighting the role of ageing in disease pathogenesis. mHtt undergoes proteolytic cleavage, misfolding, accumulation, and aggregation into inclusion bodies. The emerging model of HD pathogenesis proposes that the chronic production of misfolded mHtt overwhelms the chaperone machinery, diverting other misfolded clients to the proteasome and the autophagy pathways, ultimately leading to a global collapse of the proteostasis network. Multiple converging hypotheses also implicate ageing and its impact in the dysfunction of organelles as additional contributing factors to the collapse of proteostasis in HD. In particular, mitochondrial function is required to sustain the activity of ATP-dependent chaperones and proteolytic machinery. Recent studies elucidating mitochondria-endoplasmic reticulum interactions and uncovering a dedicated proteostasis machinery in mitochondria, suggest that mitochondria play a more active role in the maintenance of cellular proteostasis than previously thought. The enhancement of cytosolic proteostasis pathways shows promise for HD treatment, protecting cells from the detrimental effects of mHtt accumulation. In this review, we consider how mHtt and its post translational modifications interfere with protein quality control pathways, and how the pharmacological and genetic modulation of components of the proteostasis network impact disease phenotypes in cellular and in vivo HD models.
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Affiliation(s)
- Tânia R Soares
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal; Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - Sara D Reis
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal
| | - Brígida R Pinho
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK
| | - Jorge M A Oliveira
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK.
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13
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Zhu LN, Qiao HH, Chen L, Sun LP, Hui JL, Lian YL, Xie WB, Ding JY, Meng YL, Zhu BF, Qiu PM. SUMOylation of Alpha-Synuclein Influences on Alpha-Synuclein Aggregation Induced by Methamphetamine. Front Cell Neurosci 2018; 12:262. [PMID: 30197588 PMCID: PMC6117395 DOI: 10.3389/fncel.2018.00262] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022] Open
Abstract
Methamphetamine (METH) is an illegal and widely abused psychoactive stimulant. METH abusers are at high risk of neurodegenerative disorders, including Parkinson’s disease (PD). Previous studies have demonstrated that METH causes alpha-synuclein (α-syn) aggregation in the both laboratory animal and human. In this study, exposure to high METH doses increased the expression of α-syn and the small ubiquitin-related modifier 1 (SUMO-1). Therefore, we hypothesized that SUMOylation of α-syn is involved in high-dose METH-induced α-syn aggregation. We measured the levels of α-syn SUMOylation and these enzymes involved in the SUMOylation cycle in SH-SY5Y human neuroblastoma cells (SH-SY5Y cells), in cultures of C57 BL/6 primary mouse neurons and in brain tissues of mice exposure to METH. We also demonstrated the effect of α-syn SUMOylation on α-syn aggregation after METH exposure by overexpressing the key enzyme of the SUMOylation cycle or silencing SUMO-1 expression in vitro. Then, we make introduced mutations in the major SUMOylation acceptor sites of α-syn by transfecting a lentivirus containing the sequence of WT α-syn or K96/102R α-syn into SH-SY5Y cells and injecting an adenovirus containing the sequence of WT α-syn or K96/102R α-syn into the mouse striatum. Levels of the ubiquitin-proteasome system (UPS)-related makers ubiquitin (Ub) and UbE1, as well as the autophagy-lysosome pathway (ALP)-related markers LC3, P62 and lysosomal associated membrane protein 2A (LAMP2A), were also measured in SH-SY5Y cells transfected with lentivirus and mice injected with adenovirus. The results showed that METH exposure decreases the SUMOylation level of α-syn, although the expression of α-syn and SUMO-1 are increased. One possible cause is the reduction of UBC9 level. The increase in α-syn SUMOylation by UBC9 overexpression relieves METH-induced α-syn overexpression and aggregation, whereas the decrease in α-syn SUMOylation by SUMO-1 silencing exacerbates the same pathology. Furthermore, mutations in the major SUMOylation acceptor sites of α-syn also aggravate α-syn overexpression and aggregation by impairing degradation through the UPS and the ALP in vitro and in vivo. These results suggest that SUMOylation of α-syn plays a fundamental part in α-syn overexpression and aggregation induced by METH and could be a suitable target for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Lin-Nan Zhu
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Hong-Hua Qiao
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Ling Chen
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Le-Ping Sun
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Jia-Liang Hui
- First Clinical Medical College, Southern Medical University, Guangzhou, China
| | - Yong-Ling Lian
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Wei-Bing Xie
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Jiu-Yang Ding
- School of Forensic Medicine, Southern Medical University, Guangzhou, China.,Department of Anatomy, Zunyi Medical College, Zunyi, China
| | - Yun-le Meng
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Bo-Feng Zhu
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Ping-Ming Qiu
- School of Forensic Medicine, Southern Medical University, Guangzhou, China
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14
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Moruno-Manchon JF, Koellhoffer EC, Gopakumar J, Hambarde S, Kim N, McCullough LD, Tsvetkov AS. The G-quadruplex DNA stabilizing drug pyridostatin promotes DNA damage and downregulates transcription of Brca1 in neurons. Aging (Albany NY) 2018; 9:1957-1970. [PMID: 28904242 PMCID: PMC5636668 DOI: 10.18632/aging.101282] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/25/2017] [Indexed: 01/01/2023]
Abstract
The G-quadruplex is a non-canonical DNA secondary structure formed by four DNA strands containing multiple runs of guanines. G-quadruplexes play important roles in DNA recombination, replication, telomere maintenance, and regulation of transcription. Small molecules that stabilize the G-quadruplexes alter gene expression in cancer cells. Here, we hypothesized that the G-quadruplexes regulate transcription in neurons. We discovered that pyridostatin, a small molecule that specifically stabilizes G-quadruplex DNA complexes, induced neurotoxicity and promoted the formation of DNA double–strand breaks (DSBs) in cultured neurons. We also found that pyridostatin downregulated transcription of the Brca1 gene, a gene that is critical for DSB repair. Importantly, in an in vitro gel shift assay, we discovered that an antibody specific to the G-quadruplex structure binds to a synthetic oligonucleotide, which corresponds to the first putative G-quadruplex in the Brca1 gene promoter. Our results suggest that the G-quadruplex complexes regulate transcription in neurons. Studying the G-quadruplexes could represent a new avenue for neurodegeneration and brain aging research.
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Affiliation(s)
- Jose F Moruno-Manchon
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School at Houston, TX 77030, USA
| | - Edward C Koellhoffer
- Department of Neurology, the University of Texas McGovern Medical School at Houston, TX 77030, USA
| | - Jayakrishnan Gopakumar
- Summer Research Program at the University of Texas McGovern Medical School at Houston, TX 77030, USA
| | - Shashank Hambarde
- Department of Microbiology and Molecular Genetics, the University of Texas McGovern Medical School at Houston, TX 77030, USA
| | - Nayun Kim
- Department of Microbiology and Molecular Genetics, the University of Texas McGovern Medical School at Houston, TX 77030, USA.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Louise D McCullough
- Department of Neurology, the University of Texas McGovern Medical School at Houston, TX 77030, USA.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Andrey S Tsvetkov
- Department of Neurobiology and Anatomy, the University of Texas McGovern Medical School at Houston, TX 77030, USA.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA.,UTHealth Consortium on Aging, the University of Texas McGovern Medical School, Houston, TX 77030, USA
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15
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Luis-Ravelo D, Estévez-Silva H, Barroso-Chinea P, Afonso-Oramas D, Salas-Hernández J, Rodríguez-Núñez J, Acevedo-Arozena A, Marcellino D, González-Hernández T. Pramipexole reduces soluble mutant huntingtin and protects striatal neurons through dopamine D3 receptors in a genetic model of Huntington's disease. Exp Neurol 2018; 299:137-147. [DOI: 10.1016/j.expneurol.2017.10.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/29/2017] [Accepted: 10/19/2017] [Indexed: 12/26/2022]
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16
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Moruno Manchon JF, Uzor NE, Finkbeiner S, Tsvetkov AS. SPHK1/sphingosine kinase 1-mediated autophagy differs between neurons and SH-SY5Y neuroblastoma cells. Autophagy 2018; 12:1418-24. [PMID: 27467777 DOI: 10.1080/15548627.2016.1183082] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Although implicated in neurodegeneration, autophagy has been characterized mostly in yeast and mammalian non-neuronal cells. In a recent study, we sought to determine if SPHK1 (sphingosine kinase 1), implicated previously in macroautophagy/autophagy in cancer cells, regulates autophagy in neurons. SPHK1 synthesizes sphingosine-1-phosphate (S1P), a bioactive lipid involved in cell survival. In our study, we discovered that, when neuronal autophagy is pharmacologically stimulated, SPHK1 relocalizes to the endocytic and autophagic organelles. Interestingly, in non-neuronal cells stimulated with growth factors, SPHK1 translocates to the plasma membrane, where it phosphorylates sphingosine to produce S1P. Whether SPHK1 also binds to the endocytic and autophagic organelles in non-neuronal cells upon induction of autophagy has not been demonstrated. Here, we determined if the effect in neurons is operant in the SH-SY5Y neuroblastoma cell line. In both non-differentiated and differentiated SH-SY5Y cells, a short incubation of cells in amino acid-free medium stimulated the formation of SPHK1-positive puncta, as in neurons. We also found that, unlike neurons in which these puncta represent endosomes, autophagosomes, and amphisomes, in SH-SY5Y cells SPHK1 is bound only to the endosomes. In addition, a dominant negative form of SPHK1 was very toxic to SH-SY5Y cells, but cultured primary cortical neurons tolerated it significantly better. These results suggest that autophagy in neurons is regulated by mechanisms that differ, at least in part, from those in SH-SY5Y cells.
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Affiliation(s)
- Jose Felix Moruno Manchon
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA
| | - Ndidi-Ese Uzor
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA.,b University of Texas Graduate School of Biomedical Sciences , Houston , TX , USA
| | - Steven Finkbeiner
- c Gladstone Institute of Neurological Disease and the Taube/Koret Center for Neurodegenerative Disease Research , San Francisco , CA , USA.,d Departments of Neurology and Physiology , University of California , San Francisco , CA , USA
| | - Andrey S Tsvetkov
- a Department of Neurobiology and Anatomy , the University of Texas McGovern Medical School , Houston , TX , USA.,b University of Texas Graduate School of Biomedical Sciences , Houston , TX , USA
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17
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Huang N, Erie C, Lu ML, Wei J. Aberrant subcellular localization of SQSTM1/p62 contributes to increased vulnerability to proteotoxic stress recovery in Huntington's disease. Mol Cell Neurosci 2017; 88:43-52. [PMID: 29246658 DOI: 10.1016/j.mcn.2017.12.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 12/08/2017] [Accepted: 12/10/2017] [Indexed: 10/18/2022] Open
Abstract
Proteotoxic stress plays an important role in the pathogenesis of Huntington's disease (HD). Autophagy is proposed as a compensatory mechanism to remove protein aggregates under proteotoxic stress by up-regulating p62 expression. In the present study, we investigated the molecular action of p62 to proteotoxic stress in HD cells. Using two different HD cellular models, STHdhQ7 and STHdhQ111 cells derived from wild type and HD knock-in mice and human fibroblasts from healthy and HD patients, we found that HD cells are more vulnerable to cell death under proteotoxic stress and during stress recovery. We further showed that P62 was up-regulated in both STHdhQ7 and STHdhQ111 cells in response to the stress with distinct subcellular localization patterns. While dispersed p62 puncti were found in STHdhQ7 cells, p62 bodies were initially present in the lysosomes and accumulated to the juxtanuclear regions of STHdhQ111 cells as MG132 incubation continued. Unlike in STHdhQ7 cells, p62 puncti were not associated with K48-linked polyubiquitinated protein aggregates or proteasomal components in STHdhQ111. Interestingly, addition of cysteine during MG132 incubation rescued cell death in STHdhQ111 cells caused by stress recovery and altered the subcellular distribution of p62. Our data suggest that aberrant positioning of p62 affects the proteasomal clearance of protein aggregates and may contribute to the increased vulnerability to proteotoxic stress-induced cell death in HD cells.
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Affiliation(s)
- Ningjing Huang
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton 33431, FL, USA; Department of Neurology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, China
| | - Christine Erie
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton 33431, FL, USA
| | - Michael L Lu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton 33431, FL, USA
| | - Jianning Wei
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton 33431, FL, USA.
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18
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Bhat P, Kriel J, Shubha Priya B, Basappa, Shivananju NS, Loos B. Modulating autophagy in cancer therapy: Advancements and challenges for cancer cell death sensitization. Biochem Pharmacol 2017; 147:170-182. [PMID: 29203368 DOI: 10.1016/j.bcp.2017.11.021] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/30/2017] [Indexed: 02/07/2023]
Abstract
Autophagy is a major protein degradation pathway capable of upholding cellular metabolism under nutrient limiting conditions, making it a valuable resource to highly proliferating tumour cells. Although the regulatory machinery of the autophagic pathway has been well characterized, accurate modulation of this pathway remains complex in the context of clinical translatability for improved cancer therapies. In particular, the dynamic relationship between the rate of protein degradation through autophagy, i.e. autophagic flux, and the susceptibility of tumours to undergo apoptosis remains largely unclear. Adding to inefficient clinical translation is the lack of measurement techniques that accurately depict autophagic flux. Paradoxically, both increased autophagic flux as well as autophagy inhibition have been shown to sensitize cancer cells to undergo cell death, indicating the highly context dependent nature of this pathway. In this article, we aim to disentangle the role of autophagy modulation in tumour suppression by assessing existing literature in the context of autophagic flux and cellular metabolism at the interface of mitochondrial function. We highlight the urgency to not only assess autophagic flux more accurately, but also to center autophagy manipulation within the unique and inherent metabolic properties of cancer cells. Lastly, we discuss the challenges faced when targeting autophagy in the clinical setting. In doing so, it is hoped that a better understanding of autophagy in cancer therapy is revealed in order to overcome tumour chemoresistance through more controlled autophagy modulation in the future.
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Affiliation(s)
- Punya Bhat
- DOS in Chemistry, University of Mysore, Manasgangotri, Mysuru 570006, Karnataka, India
| | - Jurgen Kriel
- Department of Physiological Sciences, Faculty of Science, University of Stellenbosch, Stellenbosch 7600, South Africa
| | - Babu Shubha Priya
- DOS in Chemistry, University of Mysore, Manasgangotri, Mysuru 570006, Karnataka, India
| | - Basappa
- Laboratory of Chemical Biology, Department of studies in Organic Chemistry, Manasagangotri, University of Mysore, Mysore 570006, India
| | - Nanjunda Swamy Shivananju
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS TEI Campus, Mysuru 57006, Karnataka, India.
| | - Ben Loos
- Department of Physiological Sciences, Faculty of Science, University of Stellenbosch, Stellenbosch 7600, South Africa.
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Jimenez-Sanchez M, Licitra F, Underwood BR, Rubinsztein DC. Huntington's Disease: Mechanisms of Pathogenesis and Therapeutic Strategies. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a024240. [PMID: 27940602 DOI: 10.1101/cshperspect.a024240] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Huntington's disease is a late-onset neurodegenerative disease caused by a CAG trinucleotide repeat in the gene encoding the huntingtin protein. Despite its well-defined genetic origin, the molecular and cellular mechanisms underlying the disease are unclear and complex. Here, we review some of the currently known functions of the wild-type huntingtin protein and discuss the deleterious effects that arise from the expansion of the CAG repeats, which are translated into an abnormally long polyglutamine tract. Finally, we outline some of the therapeutic strategies that are currently being pursued to slow down the disease.
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Affiliation(s)
- Maria Jimenez-Sanchez
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge CB2 0XY, United Kingdom
| | - Floriana Licitra
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge CB2 0XY, United Kingdom
| | - Benjamin R Underwood
- Department of Old Age Psychiatry, Beechcroft, Fulbourn Hospital, Cambridge CB21 5EF, United Kingdom
| | - David C Rubinsztein
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge CB2 0XY, United Kingdom
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20
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Abstract
Maintaining synaptic integrity and function depends on the continuous removal and degradation of aged or damaged proteins. Synaptic protein degradation has received considerable attention in the context of synaptic plasticity and growing interest in relation to neurodegenerative and other disorders. Conversely, less attention has been given to constitutive, ongoing synaptic protein degradation and the roles canonical degradation pathways play in these processes. Here we briefly review recent progress on this topic and new experimental approaches which have expedited such progress and highlight several emerging principles. These include the realization that synaptic proteins typically have unusually long lifetimes, as might be expected from the remote locations of most synaptic sites; the possibility that degradation pathways can change with time from synthesis, cellular context, and physiological input; and that degradation pathways, other than ubiquitin-proteasomal-mediated degradation, might play key roles in constitutive protein degradation at synaptic sites. Finally, we point to the importance of careful experimental design and sufficiently sensitive techniques for studying synaptic protein degradation, which bring into account their slow turnover rates and complex life cycles.
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Affiliation(s)
- Laurie D Cohen
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion City, Haifa, 32000, Israel
| | - Noam E Ziv
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Technion City, Haifa, 32000, Israel
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21
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van Hagen M, Piebes DGE, de Leeuw WC, Vuist IM, van Roon-Mom WMC, Moerland PD, Verschure PJ. The dynamics of early-state transcriptional changes and aggregate formation in a Huntington's disease cell model. BMC Genomics 2017; 18:373. [PMID: 28499347 PMCID: PMC5429582 DOI: 10.1186/s12864-017-3745-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 05/01/2017] [Indexed: 11/17/2022] Open
Abstract
Background Huntington’s disease (HD) is a fatal neurodegenerative disorder caused by a CAG expansion in the Huntingtin (HTT) gene. Proteolytic cleavage of mutant huntingtin (Htt) protein with an expanded polyglutamine (polyQ) stretch results in production of Htt fragments that aggregate and induce impaired ubiquitin proteasome, mitochondrial functioning and transcriptional dysregulation. To understand the time-resolved relationship between aggregate formation and transcriptional changes at early disease stages, we performed temporal transcriptome profiling and quantification of aggregate formation in living cells in an inducible HD cell model. Results Rat pheochromocytoma (PC12) cells containing a stably integrated, doxycycline-inducible, eGFP-tagged N-terminal human Htt fragment with an expanded polyQ domain were used to analyse gene expression changes at different stages of mutant Htt aggregation. At earliest time points after doxycycline induction no detectable aggregates and few changes in gene expression were observed. Aggregates started to appear at intermediate time points. Aggregate formation and subsequent enlargement of aggregates coincided with a rapid increase in the number of differentially expressed (DE) genes. The increase in number of large aggregates coincided with a decrease in the number of smaller aggregates whereas the transcription profile reverted towards the profile observed before mutant Htt induction. Cluster-based analysis of the 2,176 differentially expressed genes revealed fourteen distinct clusters responding differently over time. Functional enrichment analysis of the two major gene clusters revealed that genes in the up-regulated cluster were mainly involved in metabolic (antioxidant activity and cellular ketone metabolic processes) and genes in the down-regulated cluster in developmental processes, respectively. Promoter-based analysis of the identified gene clusters resulted in identification of a transcription factor network of which several previously have been linked to HD. Conclusions We demonstrate a time-resolved relationship between Htt aggregation and changes in the transcriptional profile. We identified two major gene clusters showing involvement of (i) mitochondrial dysfunction and (ii) developmental processes implying cellular homeostasis defects. We identified novel and known HD-linked transcription factors and show their interaction with known and predicted regulatory proteins. Our data provide a novel resource for hypothesis building on the role of transcriptional key regulators in early stages of HD and possibly other polyQ-dependent diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3745-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martijn van Hagen
- Synthetic, Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.,Bioinformatics Laboratory, Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Diewertje G E Piebes
- Synthetic, Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Wim C de Leeuw
- MicroArray Department, University of Amsterdam, Amsterdam, The Netherlands
| | - Ilona M Vuist
- Synthetic, Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Perry D Moerland
- Bioinformatics Laboratory, Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Pernette J Verschure
- Synthetic, Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
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22
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Carnemolla A, Michelazzi S, Agostoni E. PIN1 Modulates Huntingtin Levels and Aggregate Accumulation: An In vitro Model. Front Cell Neurosci 2017; 11:121. [PMID: 28533744 PMCID: PMC5420564 DOI: 10.3389/fncel.2017.00121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 04/12/2017] [Indexed: 12/02/2022] Open
Abstract
Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder characterized by a polyglutamine expansion within the N-terminal region of huntingtin protein (HTT). Cellular mechanisms promoting mutant huntingtin (mHTT) clearance are of great interest in HD pathology as they can lower the level of the mutant protein and its toxic aggregated species, thus affecting disease onset and progression. We have previously shown that the prolyl-isomerase PIN1 represents a promising negative regulator of mHTT aggregate accumulation using a genetically precise HD mouse model, namely HdhQ111 mice. Therefore, the current study aims at underpinning the mechanism by which PIN1 affects huntingtin's aggregates. We found that PIN1 overexpression led to a reduction of mHTT aggregates in HEK293 cells, and that this could be linked to a negative regulation of mHTT half-life by PIN1. Furthermore, we show that PIN1 has the ability to stimulate the proteasome presenting evidence of a mechanism regulating this phenomenon. Our findings provide a rationale for future investigation into PIN1 with the potential for the development of novel therapeutic strategies.
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Affiliation(s)
- Alisia Carnemolla
- International School for Advanced Studies, Area of NeuroscienceTrieste, Italy
| | - Silvia Michelazzi
- International School for Advanced Studies, Area of NeuroscienceTrieste, Italy
| | - Elena Agostoni
- International School for Advanced Studies, Area of NeuroscienceTrieste, Italy
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23
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Moruno-Manchon JF, Uzor NE, Blasco-Conesa MP, Mannuru S, Putluri N, Furr-Stimming EE, Tsvetkov AS. Inhibiting sphingosine kinase 2 mitigates mutant Huntingtin-induced neurodegeneration in neuron models of Huntington disease. Hum Mol Genet 2017; 26:1305-1317. [PMID: 28175299 PMCID: PMC6251541 DOI: 10.1093/hmg/ddx046] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/20/2017] [Accepted: 02/02/2017] [Indexed: 12/22/2022] Open
Abstract
Huntington disease (HD) is the most common inherited neurodegenerative disorder. It has no cure. The protein huntingtin causes HD, and mutations to it confer toxic functions to the protein that lead to neurodegeneration. Thus, identifying modifiers of mutant huntingtin-mediated neurotoxicity might be a therapeutic strategy for HD. Sphingosine kinases 1 (SK1) and 2 (SK2) synthesize sphingosine-1-phosphate (S1P), a bioactive lipid messenger critically involved in many vital cellular processes, such as cell survival. In the nucleus, SK2 binds to and inhibits histone deacetylases 1 and 2 (HDAC1/2). Inhibiting both HDACs has been suggested as a potential therapy in HD. Here, we found that SK2 is nuclear in primary neurons and, unexpectedly, overexpressed SK2 is neurotoxic in a dose-dependent manner. SK2 promotes DNA double-strand breaks in cultured primary neurons. We also found that SK2 is hyperphosphorylated in the brain samples from a model of HD, the BACHD mice. These data suggest that the SK2 pathway may be a part of a pathogenic pathway in HD. ABC294640, an inhibitor of SK2, reduces DNA damage in neurons and increases survival in two neuron models of HD. Our results identify a novel regulator of mutant huntingtin-mediated neurotoxicity and provide a new target for developing therapies for HD.
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Affiliation(s)
- Jose F. Moruno-Manchon
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, TX 77030, USA
| | - Ndidi-Ese Uzor
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, TX 77030, USA
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Maria P. Blasco-Conesa
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, TX 77030, USA
| | - Sishira Mannuru
- The University of Texas Medical Training Program, Houston, TX 77030, USA
| | - Nagireddy Putluri
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Erin E. Furr-Stimming
- Department of Neurology, The University of Texas McGovern Medical School, Houston, TX 77030, USA
| | - Andrey S. Tsvetkov
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, TX 77030, USA
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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24
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Ben Yehuda A, Risheq M, Novoplansky O, Bersuker K, Kopito RR, Goldberg M, Brandeis M. Ubiquitin Accumulation on Disease Associated Protein Aggregates Is Correlated with Nuclear Ubiquitin Depletion, Histone De-Ubiquitination and Impaired DNA Damage Response. PLoS One 2017; 12:e0169054. [PMID: 28052107 PMCID: PMC5215683 DOI: 10.1371/journal.pone.0169054] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/09/2016] [Indexed: 12/29/2022] Open
Abstract
Deposition of ubiquitin conjugates on inclusion bodies composed of protein aggregates is a definitive cytopathological hallmark of neurodegenerative diseases. We show that accumulation of ubiquitin on polyQ IB, associated with Huntington’s disease, is correlated with extensive depletion of nuclear ubiquitin and histone de-ubiquitination. Histone ubiquitination plays major roles in chromatin regulation and DNA repair. Accordingly, we observe that cells expressing IB fail to respond to radiomimetic DNA damage, to induce gamma-H2AX phosphorylation and to recruit 53BP1 to damaged foci. Interestingly ubiquitin depletion, histone de-ubiquitination and impaired DNA damage response are not restricted to PolyQ aggregates and are associated with artificial aggregating luciferase mutants. The longevity of brain neurons depends on their capacity to respond to and repair extensive ongoing DNA damage. Impaired DNA damage response, even modest one, could thus lead to premature neuron aging and mortality.
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Affiliation(s)
- Adi Ben Yehuda
- The Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem Safra Campus, Jerusalem, Israel
| | - Marwa Risheq
- The Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem Safra Campus, Jerusalem, Israel
| | - Ofra Novoplansky
- The Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem Safra Campus, Jerusalem, Israel
| | - Kirill Bersuker
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Ron R. Kopito
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Michal Goldberg
- The Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem Safra Campus, Jerusalem, Israel
| | - Michael Brandeis
- The Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem Safra Campus, Jerusalem, Israel
- * E-mail:
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25
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Ntsapi C, Loos B. Caloric restriction and the precision-control of autophagy: A strategy for delaying neurodegenerative disease progression. Exp Gerontol 2016; 83:97-111. [DOI: 10.1016/j.exger.2016.07.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 07/18/2016] [Accepted: 07/25/2016] [Indexed: 01/07/2023]
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26
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Levetiracetam mitigates doxorubicin-induced DNA and synaptic damage in neurons. Sci Rep 2016; 6:25705. [PMID: 27168474 PMCID: PMC4863375 DOI: 10.1038/srep25705] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/21/2016] [Indexed: 02/07/2023] Open
Abstract
Neurotoxicity may occur in cancer patients and survivors during or after chemotherapy. Cognitive deficits associated with neurotoxicity can be subtle or disabling and frequently include disturbances in memory, attention, executive function and processing speed. Searching for pathways altered by anti-cancer treatments in cultured primary neurons, we discovered that doxorubicin, a commonly used anti-neoplastic drug, significantly decreased neuronal survival. The drug promoted the formation of DNA double-strand breaks in primary neurons and reduced synaptic and neurite density. Pretreatment of neurons with levetiracetam, an FDA-approved anti-epileptic drug, enhanced survival of chemotherapy drug-treated neurons, reduced doxorubicin-induced formation of DNA double-strand breaks, and mitigated synaptic and neurite loss. Thus, levetiracetam might be part of a valuable new approach for mitigating synaptic damage and, perhaps, for treating cognitive disturbances in cancer patients and survivors.
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27
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Lin L, Jin Z, Tan H, Xu Q, Peng T, Li H. Atypical ubiquitination by E3 ligase WWP1 inhibits the proteasome-mediated degradation of mutant huntingtin. Brain Res 2016; 1643:103-12. [PMID: 27107943 DOI: 10.1016/j.brainres.2016.03.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/10/2016] [Accepted: 03/18/2016] [Indexed: 11/19/2022]
Abstract
Huntington's disease (HD) is caused by the expansion of CAG trinucleotide repeats in exon 1 of HD gene encoding huntingtin (Htt), which is characterized by aggregation and formation of mutant Htt containing expanded polyglutamine (polyQ) repeats. Dysfunction of the ubiquitin-proteasome system (UPS) plays a critical role in the pathogenesis of HD. As the linkage mediator between ubiquitin and specific target proteins, E3 ubiquitin ligases have been suggested to be involved in mHtt degradation and HD pathology. However, the potential involvement of the E3 ligase WWP1 in HD has not been explored. The present study determined whether WWP1 is involved in the development of HD in both in vivo and in vitro models. The results showed that in contrast to several other E3 ligases, expression of WWP1 is enhanced in mice and N2a cells expressing mutant Htt (160Q) and co-localized with mHtt protein aggregates. In addition, expression of WWP1 positively regulates mutan Htt levels, aggregate formation, and cell toxicity. Further analysis revealed that WWP1 ubiquitinated mHtt at an atypical position of Lys-63, which may have inhibited degradation of mutant Htt through the ubiquitin-proteasome pathway. In conclusion, these results suggested that the E3 ligase WWP1 is involved in the pathogenesis of HD; therefore, it may be a novel target for therapeutic intervention.
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Affiliation(s)
- Li Lin
- Division of Histology and Embryology, Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Zhenzhen Jin
- Division of Histology and Embryology, Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Huiping Tan
- Division of Histology and Embryology, Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Qiaoqiao Xu
- Division of Histology and Embryology, Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Ting Peng
- Division of Histology and Embryology, Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China; (b)Key Laboratory for Neurological Disorders of Education Ministry,Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China; (c)Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
| | - He Li
- Division of Histology and Embryology, Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China; (b)Key Laboratory for Neurological Disorders of Education Ministry,Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China; (c)Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China.
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28
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Protein aggregation and ER stress. Brain Res 2016; 1648:658-666. [PMID: 27037184 DOI: 10.1016/j.brainres.2016.03.044] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/26/2016] [Accepted: 03/28/2016] [Indexed: 12/12/2022]
Abstract
Protein aggregation is a common feature of the protein misfolding or conformational diseases, among them most of the neurodegenerative diseases. These disorders are a major scourge, with scarce if any effective therapies at present. Recent research has identified ER stress as a major mechanism implicated in cytotoxicity in these diseases. Whether amyloid-β or tau in Alzheimer's, α-synuclein in Parkinson's, huntingtin in Huntington's disease or other aggregation-prone proteins in many other neurodegenerative diseases, there is a shared pathway of oligomerization and aggregation into amyloid fibrils. There is increasing evidence in recent years that the toxic species, and those that evoke ER stress, are the intermediate oligomeric forms and not the final amyloid aggregates. This review focuses on recent findings on the mechanisms and importance of the development of ER stress upon protein aggregation, especially in neurodegenerative diseases, and possible therapeutic approaches that are being examined. This article is part of a Special Issue entitled SI:ER stress.
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29
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Essential role of proteasomes in maintaining self-renewal in neural progenitor cells. Sci Rep 2016; 6:19752. [PMID: 26804982 PMCID: PMC4726439 DOI: 10.1038/srep19752] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/17/2015] [Indexed: 11/29/2022] Open
Abstract
Protein turnover and homeostasis are regulated by the proteasomal system, which is critical for cell function and viability. Pluripotency of stem cells also relies on normal proteasomal activity that mitigates senescent phenotypes induced by intensive cell replications, as previously demonstrated in human bone marrow stromal cells. In this study, we investigated the role of proteasomes in self-renewal of neural progenitor cells (NPCs). Through both in vivo and in vitro analyses, we found that the expression of proteasomes was progressively decreased during aging. Likewise, proliferation and self-renewal of NPCs were also impaired in aged mice, suggesting that the down-regulation of proteasomes might be responsible for this senescent phenotype. Lowering proteasomal activity by loss-of-function manipulations mimicked the senescence of NPCs both in vitro and in vivo; conversely, enhancing proteasomal activity restored and improved self-renewal in aged NPCs. These results collectively indicate that proteasomes work as a key regulator in promoting self-renewal of NPCs. This potentially provides a promising therapeutic target for age-dependent neurodegenerative diseases.
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30
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Vázquez-Manrique RP, Farina F, Cambon K, Dolores Sequedo M, Parker AJ, Millán JM, Weiss A, Déglon N, Neri C. AMPK activation protects from neuronal dysfunction and vulnerability across nematode, cellular and mouse models of Huntington's disease. Hum Mol Genet 2015; 25:1043-58. [PMID: 26681807 PMCID: PMC4764188 DOI: 10.1093/hmg/ddv513] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 12/10/2015] [Indexed: 12/25/2022] Open
Abstract
The adenosine monophosphate activated kinase protein (AMPK) is an evolutionary-conserved protein important for cell survival and organismal longevity through the modulation of energy homeostasis. Several studies suggested that AMPK activation may improve energy metabolism and protein clearance in the brains of patients with vascular injury or neurodegenerative disease. However, in Huntington's disease (HD), AMPK may be activated in the striatum of HD mice at a late, post-symptomatic phase of the disease, and high-dose regiments of the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide may worsen neuropathological and behavioural phenotypes. Here, we revisited the role of AMPK in HD using models that recapitulate the early features of the disease, including Caenorhabditis elegans neuron dysfunction before cell death and mouse striatal cell vulnerability. Genetic and pharmacological manipulation of aak-2/AMPKα shows that AMPK activation protects C. elegans neurons from the dysfunction induced by human exon-1 huntingtin (Htt) expression, in a daf-16/forkhead box O-dependent manner. Similarly, AMPK activation using genetic manipulation and low-dose metformin treatment protects mouse striatal cells expressing full-length mutant Htt (mHtt), counteracting their vulnerability to stress, with reduction of soluble mHtt levels by metformin and compensation of cytotoxicity by AMPKα1. Furthermore, AMPK protection is active in the mouse brain as delivery of gain-of-function AMPK-γ1 to mouse striata slows down the neurodegenerative effects of mHtt. Collectively, these data highlight the importance of considering the dynamic of HD for assessing the therapeutic potential of stress-response targets in the disease. We postulate that AMPK activation is a compensatory response and valid approach for protecting dysfunctional and vulnerable neurons in HD.
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Affiliation(s)
- Rafael P Vázquez-Manrique
- CNRS, UMR 8256, Laboratory of Neuronal Cell Biology and Pathology, Paris, France, Sorbonnes Universités, University Pierre and Marie Curie (UPMC) Univ Paris 06, Paris, France, Molecular, Cellular and Genomic Biomedicine Research Group, Health Research Institute-La Fe and CIBER de Enfermedades Raras (CIBERER), Valencia, Spain,
| | - Francesca Farina
- CNRS, UMR 8256, Laboratory of Neuronal Cell Biology and Pathology, Paris, France, Sorbonnes Universités, University Pierre and Marie Curie (UPMC) Univ Paris 06, Paris, France
| | - Karine Cambon
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Département des Sciences du Vivant (DSV), Institut d'Imagerie Biomédicale (I2BM), MIRCen, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, UMR 9199, Neurodegenerative Diseases Laboratory, F-92260 Fontenay-aux-Roses, France
| | - María Dolores Sequedo
- Molecular, Cellular and Genomic Biomedicine Research Group, Health Research Institute-La Fe and CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Alex J Parker
- CRCHUM, Montréal, Canada, Department de Neurosciences, Faculté de médecine, Université de Montréal, Montréal, Canada
| | - José María Millán
- Molecular, Cellular and Genomic Biomedicine Research Group, Health Research Institute-La Fe and CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Andreas Weiss
- Evotec AG, Manfred Eigen Campus, Hamburg, Germany and
| | - Nicole Déglon
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Département des Sciences du Vivant (DSV), Institut d'Imagerie Biomédicale (I2BM), MIRCen, Department of Clinical Neurosciences (DNC), Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Christian Neri
- CNRS, UMR 8256, Laboratory of Neuronal Cell Biology and Pathology, Paris, France, Sorbonnes Universités, University Pierre and Marie Curie (UPMC) Univ Paris 06, Paris, France,
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31
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Moruno Manchon JF, Uzor NE, Dabaghian Y, Furr-Stimming EE, Finkbeiner S, Tsvetkov AS. Cytoplasmic sphingosine-1-phosphate pathway modulates neuronal autophagy. Sci Rep 2015; 5:15213. [PMID: 26477494 PMCID: PMC4609990 DOI: 10.1038/srep15213] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/21/2015] [Indexed: 12/13/2022] Open
Abstract
Autophagy is an important homeostatic mechanism that eliminates long-lived proteins, protein aggregates and damaged organelles. Its dysregulation is involved in many neurodegenerative disorders. Autophagy is therefore a promising target for blunting neurodegeneration. We searched for novel autophagic pathways in primary neurons and identified the cytosolic sphingosine-1-phosphate (S1P) pathway as a regulator of neuronal autophagy. S1P, a bioactive lipid generated by sphingosine kinase 1 (SK1) in the cytoplasm, is implicated in cell survival. We found that SK1 enhances flux through autophagy and that S1P-metabolizing enzymes decrease this flux. When autophagy is stimulated, SK1 relocalizes to endosomes/autophagosomes in neurons. Expression of a dominant-negative form of SK1 inhibits autophagosome synthesis. In a neuron model of Huntington’s disease, pharmacologically inhibiting S1P-lyase protected neurons from mutant huntingtin-induced neurotoxicity. These results identify the S1P pathway as a novel regulator of neuronal autophagy and provide a new target for developing therapies for neurodegenerative disorders.
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Affiliation(s)
| | - Ndidi-Ese Uzor
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030
| | - Yuri Dabaghian
- The Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030.,Department of Computational and Applied Mathematics, Rice University, Houston, TX 77005
| | | | - Steven Finkbeiner
- Gladstone Institute of Neurological Disease and the Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, CA 94158.,Departments of Neurology and Physiology, University of California, San Francisco, CA 94143
| | - Andrey S Tsvetkov
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030
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Berger TR, Montie HL, Jain P, Legleiter J, Merry DE. Identification of novel polyglutamine-expanded aggregation species in spinal and bulbar muscular atrophy. Brain Res 2015; 1628:254-264. [PMID: 26453288 DOI: 10.1016/j.brainres.2015.09.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/26/2015] [Accepted: 09/28/2015] [Indexed: 11/16/2022]
Abstract
Polyglutamine-repeat disorders are part of a larger family of neurodegenerative diseases characterized by protein misfolding and aggregation. In spinal and bulbar muscular atrophy (SBMA), polyglutamine expansion within the androgen receptor (AR) causes progressive debilitating muscular atrophy and lower motor neuron loss in males. Although soluble polyglutamine-expanded aggregation species are considered toxic intermediates in the aggregation process, relatively little is known about the spectrum of structures that are formed. Here we identify novel polyglutamine-expanded AR aggregates that are SDS-soluble and bind the toxicity-predicting antibody 3B5H10. Soluble, 3B5H10-reactive aggregation species exist in low-density conformations and are larger by atomic force microscopy, suggesting that they may be less compact than later-stage, insoluble aggregates. We demonstrate disease-relevance in vivo and draw correlations with toxicity in vitro. This article is part of a Special Issue entitled SI: Neuroprotection.
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Affiliation(s)
- Tamar R Berger
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, Philadelphia, PA, USA
| | - Heather L Montie
- Philadelphia College of Osteopathic Medicine, Department of Bio-Medical Sciences, Philadelphia, PA, USA
| | - Pranav Jain
- West Virginia University, Department of Chemistry, Morgantown, WV, USA
| | - Justin Legleiter
- West Virginia University, Department of Chemistry, Morgantown, WV, USA
| | - Diane E Merry
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, Philadelphia, PA, USA.
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33
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Duncan EJ, Cheetham ME, Chapple JP, van der Spuy J. The role of HSP70 and its co-chaperones in protein misfolding, aggregation and disease. Subcell Biochem 2015; 78:243-73. [PMID: 25487025 DOI: 10.1007/978-3-319-11731-7_12] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Molecular chaperones and their associated co-chaperones are essential in health and disease as they are key facilitators of protein folding, quality control and function. In particular, the HSP70 molecular chaperone networks have been associated with neurodegenerative diseases caused by aberrant protein folding. The pathogenesis of these disorders usually includes the formation of deposits of misfolded, aggregated protein. HSP70 and its co-chaperones have been recognised as potent modulators of inclusion formation and cell survival in cellular and animal models of neurodegenerative disease. In has become evident that the HSP70 chaperone machine functions not only in folding, but also in proteasome mediated degradation of neurodegenerative disease proteins. Thus, there has been a great deal of interest in the potential manipulation of molecular chaperones as a therapeutic approach for many neurodegenerations. Furthermore, mutations in several HSP70 co-chaperones and putative co-chaperones have been identified as causing inherited neurodegenerative and cardiac disorders, directly linking the HSP70 chaperone system to human disease.
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Affiliation(s)
- Emma J Duncan
- Molecular Endocrinology Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charter House Square, EC1M 6BQ, London, UK,
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34
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Heine EM, Berger TR, Pluciennik A, Orr CR, Zboray L, Merry DE. Proteasome-mediated proteolysis of the polyglutamine-expanded androgen receptor is a late event in spinal and bulbar muscular atrophy (SBMA) pathogenesis. J Biol Chem 2015; 290:12572-84. [PMID: 25795778 DOI: 10.1074/jbc.m114.617894] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Indexed: 01/08/2023] Open
Abstract
Proteolysis of polyglutamine-expanded proteins is thought to be a required step in the pathogenesis of several neurodegenerative diseases. The accepted view for many polyglutamine proteins is that proteolysis of the mutant protein produces a "toxic fragment" that induces neuronal dysfunction and death in a soluble form; toxicity of the fragment is buffered by its incorporation into amyloid-like inclusions. In contrast to this view, we show that, in the polyglutamine disease spinal and bulbar muscular atrophy, proteolysis of the mutant androgen receptor (AR) is a late event. Immunocytochemical and biochemical analyses revealed that the mutant AR aggregates as a full-length protein, becoming proteolyzed to a smaller fragment through a process requiring the proteasome after it is incorporated into intranuclear inclusions. Moreover, the toxicity-predicting conformational antibody 3B5H10 bound to soluble full-length AR species but not to fragment-containing nuclear inclusions. These data suggest that the AR is toxic as a full-length protein, challenging the notion of polyglutamine protein fragment-associated toxicity by redefining the role of AR proteolysis in spinal and bulbar muscular atrophy pathogenesis.
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Affiliation(s)
- Erin M Heine
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Tamar R Berger
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Anna Pluciennik
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Christopher R Orr
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Lori Zboray
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Diane E Merry
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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35
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Martin DDO, Ladha S, Ehrnhoefer DE, Hayden MR. Autophagy in Huntington disease and huntingtin in autophagy. Trends Neurosci 2014; 38:26-35. [PMID: 25282404 DOI: 10.1016/j.tins.2014.09.003] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/08/2014] [Accepted: 09/09/2014] [Indexed: 01/20/2023]
Abstract
Autophagy is an important biological process that is essential for the removal of damaged organelles and toxic or aggregated proteins by delivering them to the lysosome for degradation. Consequently, autophagy has become a primary target for the treatment of neurodegenerative diseases that involve aggregating proteins. In Huntington disease (HD), an expansion of the polyglutamine (polyQ) tract in the N-terminus of the huntingtin (HTT) protein leads to protein aggregation. However, HD is unique among the neurodegenerative proteinopathies in that autophagy is not only dysfunctional but wild type (wt) HTT also appears to play several roles in regulating the dynamics of autophagy. Herein, we attempt to integrate the recently described novel roles of wtHTT and altered autophagy in HD.
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Affiliation(s)
- Dale D O Martin
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
| | - Safia Ladha
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Dagmar E Ehrnhoefer
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
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36
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Ortega Z, Lucas JJ. Ubiquitin-proteasome system involvement in Huntington's disease. Front Mol Neurosci 2014; 7:77. [PMID: 25324717 PMCID: PMC4179678 DOI: 10.3389/fnmol.2014.00077] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 09/10/2014] [Indexed: 11/13/2022] Open
Abstract
Huntington’s disease (HD) is a genetic autosomal dominant neurodegenerative disease caused by the expansion of a CAG repeat in the huntingtin (htt) gene. This triplet expansion encodes a polyglutamine stretch (polyQ) in the N-terminus of the high molecular weight (348-kDa) and ubiquitously expressed protein htt. Normal individuals have between 6 and 35 CAG triplets, while expansions longer than 40 repeats lead to HD. The onset and severity of the disease depend on the length of the polyQ tract: the longer the polyglutamine stretch (polyQ) is, the earlier the disease begins and the more severe the symptoms are. One of the main histopathological hallmarks of HD is the presence of intraneuronal proteinaceous inclusion bodies, whose prominent and invariant feature is the presence of ubiquitin (Ub); therefore, they can be detected with anti-ubiquitin and anti-proteasome antibodies. This, together with the observation that mutations in components of the ubiquitin–proteasome system (UPS) give rise to some neurodegenerative diseases, suggests that UPS impairment may be causative of HD. Even though the link between disrupted Ub homeostasis and protein aggregation to HD is undisputed, the functional significance of these correlations and their mechanistic implications remains unresolved. Moreover, there is no consistent evidence documenting an accompanying decrease in levels of free Ub or disruption of Ub pool dynamics in neurodegenerative disease or models thus suggesting that the Ub-conjugate accumulation may be benign and just underlie lesion in 26S function. In this chapter we will elaborate on the different studies that have been performed using different experimental approaches, in order to shed light to this matter.
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Affiliation(s)
- Zaira Ortega
- Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Centro Investigación Biomédica en Red Enfermedades Neurodegenerativa (CIBERNED), Madrid, Spain
| | - Jose J Lucas
- Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Centro Investigación Biomédica en Red Enfermedades Neurodegenerativa (CIBERNED), Madrid, Spain
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37
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Margulis J, Finkbeiner S. Proteostasis in striatal cells and selective neurodegeneration in Huntington's disease. Front Cell Neurosci 2014; 8:218. [PMID: 25147502 PMCID: PMC4124811 DOI: 10.3389/fncel.2014.00218] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 07/17/2014] [Indexed: 12/23/2022] Open
Abstract
Selective neuronal loss is a hallmark of neurodegenerative diseases, including Huntington’s disease (HD). Although mutant huntingtin, the protein responsible for HD, is expressed ubiquitously, a subpopulation of neurons in the striatum is the first to succumb. In this review, we examine evidence that protein quality control pathways, including the ubiquitin proteasome system, autophagy, and chaperones, are significantly altered in striatal neurons. These alterations may increase the susceptibility of striatal neurons to mutant huntingtin-mediated toxicity. This novel view of HD pathogenesis has profound therapeutic implications: protein homeostasis pathways in the striatum may be valuable targets for treating HD and other misfolded protein disorders.
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Affiliation(s)
- Julia Margulis
- Gladstone Institute of Neurological Disease, J. David Gladstone Institutes San Francisco, CA, USA ; Department of Neurology, University of California at San Francisco San Francisco, CA, USA ; Department of Physiology, University of California at San Francisco San Francisco, CA, USA
| | - Steven Finkbeiner
- Gladstone Institute of Neurological Disease, J. David Gladstone Institutes San Francisco, CA, USA ; Department of Neurology, University of California at San Francisco San Francisco, CA, USA ; Department of Physiology, University of California at San Francisco San Francisco, CA, USA ; Taube/Koret Center for Huntington's Disease Research San Francisco, CA, USA
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38
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Dantuma NP, Bott LC. The ubiquitin-proteasome system in neurodegenerative diseases: precipitating factor, yet part of the solution. Front Mol Neurosci 2014; 7:70. [PMID: 25132814 PMCID: PMC4117186 DOI: 10.3389/fnmol.2014.00070] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 07/09/2014] [Indexed: 01/17/2023] Open
Abstract
The ubiquitin-proteasome system (UPS) has been implicated in neurodegenerative diseases based on the presence of deposits consisting of ubiquitylated proteins in affected neurons. It has been postulated that aggregation-prone proteins associated with these disorders, such as α-synuclein, β-amyloid peptide, and polyglutamine proteins, compromise UPS function, and delay the degradation of other proteasome substrates. Many of these substrates play important regulatory roles in signaling, cell cycle progression, or apoptosis, and their inadvertent stabilization due to an overloaded and improperly functioning UPS may thus be responsible for cellular demise in neurodegeneration. Over the past decade, numerous studies have addressed the UPS dysfunction hypothesis using various model systems and techniques that differ in their readout and sensitivity. While an inhibitory effect of some disease proteins on the UPS has been demonstrated, increasing evidence attests that the UPS remains operative in many disease models, which opens new possibilities for treatment. In this review, we will discuss the paradigm shift that repositioned the UPS from being a prime suspect in the pathophysiology of neurodegeneration to an attractive therapeutic target that can be harnessed to accelerate the clearance of disease-linked proteins.
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Affiliation(s)
- Nico P Dantuma
- Department of Cell and Molecular Biology, Karolinska Institutet Stockholm, Sweden
| | - Laura C Bott
- Department of Cell and Molecular Biology, Karolinska Institutet Stockholm, Sweden ; Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda, MD, USA
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39
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Muller M, Leavitt BR. Iron dysregulation in Huntington's disease. J Neurochem 2014; 130:328-50. [PMID: 24717009 DOI: 10.1111/jnc.12739] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/19/2014] [Accepted: 04/07/2014] [Indexed: 12/13/2022]
Abstract
Huntington's disease (HD) is one of many neurodegenerative diseases with reported alterations in brain iron homeostasis that may contribute to neuropathogenesis. Iron accumulation in the specific brain areas of neurodegeneration in HD has been proposed based on observations in post-mortem tissue and magnetic resonance imaging studies. Altered magnetic resonance imaging signal within specific brain regions undergoing neurodegeneration has been consistently reported and interpreted as altered levels of brain iron. Biochemical studies using various techniques to measure iron species in human samples, mouse tissue, or in vitro has generated equivocal data to support such an association. Whether elevated brain iron occurs in HD, plays a significant contributing role in HD pathogenesis, or is a secondary effect remains currently unclear.
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Affiliation(s)
- Michelle Muller
- Department of Medical Genetics, Centre for Molecular Medicine & Therapeutics, University of British Columbia and Children's and Women's Hospital, Vancouver, British Columbia, Canada
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40
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Modeling the polyglutamine aggregation pathway in Huntington's disease: from basic studies to clinical applications. Subcell Biochem 2014; 65:353-88. [PMID: 23225011 DOI: 10.1007/978-94-007-5416-4_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Huntington's disease (HD) is among the polyglutamine (polyQ) disorders, which are caused by expansion of CAG-trinucleotide repeats. These disorders share common characteristics, and have thus long been thought to have a unifying pathogenic mechanism resulting from polyQ expansion. However, this scenario has recently become more complex, as studies have found multiple pathways for the assembly of disease-related polyQ protein aggregates that differ in both structure and toxicity. There are fascinating disease-specific aspects of the polyQ disorders, including the repeat-length dependence of both clinical features and the propensity of the expanded polyQ protein to aggregate. Such aggregation kinetics have proven useful in explaining the disease process. This chapter describes two risk-based stochastic kinetic models, the cumulative-damage and one-hit models, that describe genotype-phenotype correlations in patients with polyQ diseases and reflect alternative pathways of polyQ aggregation. Using repeat-length as an index, several models explore the quantitative connection between aggregation kinetics and clinical data from HD patients. The correlations between CAG repeat-length and age-of-onset are re-evaluated, and the rate of disease progression (as assessed by clinical measures and longitudinal imaging studies of brain structure) are surveyed. Finally, I present a mathematical model by which the time course of neurodegeneration in HD can be precisely predicted, and discuss the association of the models with the major controversies about HD pathogenesis.
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41
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Lai AY, Lan CP, Hasan S, Brown ME, McLaurin J. scyllo-Inositol promotes robust mutant Huntingtin protein degradation. J Biol Chem 2013; 289:3666-76. [PMID: 24352657 DOI: 10.1074/jbc.m113.501635] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Huntington disease is characterized by neuronal aggregates and inclusions containing polyglutamine-expanded huntingtin protein and peptide fragments (polyQ-Htt). We have used an established cell-based assay employing a PC12 cell line overexpressing truncated exon 1 of Htt with a 103-residue polyQ expansion that yields polyQ-Htt aggregates to investigate the fate of polyQ-Htt-drug complexes. scyllo-Inositol is an endogenous inositol stereoisomer known to inhibit accumulation and toxicity of the amyloid-β peptide and α-synuclein. In light of these properties, we investigated the effect of scyllo-inositol on polyQ-Htt accumulation. We show that scyllo-inositol lowered the number of visible polyQ-Htt aggregates and robustly decreased polyQ-Htt protein abundance without concomitant cellular toxicity. We found that scyllo-inositol-induced polyQ-Htt reduction was by rescue of degradation pathways mediated by the lysosome and by the proteasome but not autophagosomes. The rescue of degradation pathways was not a direct result of scyllo-inositol on the lysosome or proteasome but due to scyllo-inositol-induced reduction in mutant polyQ-Htt protein levels.
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Affiliation(s)
- Aaron Y Lai
- From the Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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42
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Schipper-Krom S, Juenemann K, Jansen AH, Wiemhoefer A, van den Nieuwendijk R, Smith DL, Hink MA, Bates GP, Overkleeft H, Ovaa H, Reits E. Dynamic recruitment of active proteasomes into polyglutamine initiated inclusion bodies. FEBS Lett 2013; 588:151-9. [PMID: 24291262 DOI: 10.1016/j.febslet.2013.11.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 11/20/2022]
Abstract
Neurodegenerative disorders such as Huntington's disease are hallmarked by neuronal intracellular inclusion body formation. Whether proteasomes are irreversibly recruited into inclusion bodies in these protein misfolding disorders is a controversial subject. In addition, it has been proposed that the proteasomes may become clogged by the aggregated protein fragments, leading to impairment of the ubiquitin-proteasome system. Here, we show by fluorescence pulse-chase experiments in living cells that proteasomes are dynamically and reversibly recruited into inclusion bodies. As these recruited proteasomes remain catalytically active and accessible to substrates, our results challenge the concept of proteasome sequestration and impairment in Huntington's disease, and support the reported absence of proteasome impairment in mouse models of Huntington's disease.
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Affiliation(s)
- Sabine Schipper-Krom
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, The Netherlands
| | - Katrin Juenemann
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, The Netherlands
| | - Anne H Jansen
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, The Netherlands
| | - Anne Wiemhoefer
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, The Netherlands
| | - Rianne van den Nieuwendijk
- Department of Bio-Organic Synthesis, Institute of Chemistry, University of Leiden, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Donna L Smith
- Department of Medical and Molecular Genetics, King's College London, Guy's Hospital, Great Maze Pond, SE1 9RT London, United Kingdom
| | - Mark A Hink
- Section Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Sciencepark 904, 1090 GE Amsterdam, The Netherlands
| | - Gillian P Bates
- Department of Medical and Molecular Genetics, King's College London, Guy's Hospital, Great Maze Pond, SE1 9RT London, United Kingdom
| | - Hermen Overkleeft
- Department of Bio-Organic Synthesis, Institute of Chemistry, University of Leiden, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Huib Ovaa
- Department of Cell Biology II, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Eric Reits
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, The Netherlands.
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43
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Soluble forms of polyQ-expanded huntingtin rather than large aggregates cause endoplasmic reticulum stress. Nat Commun 2013; 4:2753. [DOI: 10.1038/ncomms3753] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 10/11/2013] [Indexed: 11/08/2022] Open
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Tsvetkov AS, Arrasate M, Barmada S, Ando DM, Sharma P, Shaby BA, Finkbeiner S. Proteostasis of polyglutamine varies among neurons and predicts neurodegeneration. Nat Chem Biol 2013; 9:586-92. [PMID: 23873212 DOI: 10.1038/nchembio.1308] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 06/25/2013] [Indexed: 01/28/2023]
Abstract
In polyglutamine (polyQ) diseases, only certain neurons die, despite widespread expression of the offending protein. PolyQ expansion may induce neurodegeneration by impairing proteostasis, but protein aggregation and toxicity tend to confound conventional measurements of protein stability. Here, we used optical pulse labeling to measure effects of polyQ expansions on the mean lifetime of a fragment of huntingtin, the protein that causes Huntington's disease, in living neurons. We show that polyQ expansion reduced the mean lifetime of mutant huntingtin within a given neuron and that the mean lifetime varied among neurons, indicating differences in their capacity to clear the polypeptide. We found that neuronal longevity is predicted by the mean lifetime of huntingtin, as cortical neurons cleared mutant huntingtin faster and lived longer than striatal neurons. Thus, cell type-specific differences in turnover capacity may contribute to cellular susceptibility to toxic proteins, and efforts to bolster proteostasis in Huntington's disease, such as protein clearance, could be neuroprotective.
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Affiliation(s)
- Andrey S Tsvetkov
- 1] Gladstone Institute of Neurological Disease, San Francisco, California, USA. [2] Taube-Koret Center for Neurodegenerative Disease Research, San Francisco, California, USA
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45
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Eremenko E, Ben-Zvi A, Morozova-Roche LA, Raveh D. Aggregation of human S100A8 and S100A9 amyloidogenic proteins perturbs proteostasis in a yeast model. PLoS One 2013; 8:e58218. [PMID: 23483999 PMCID: PMC3590125 DOI: 10.1371/journal.pone.0058218] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 02/01/2013] [Indexed: 12/31/2022] Open
Abstract
Amyloid aggregates of the calcium-binding EF-hand proteins, S100A8 and S100A9, have been found in the corpora amylacea of patients with prostate cancer and may play a role in carcinogenesis. Here we present a novel model system using the yeast Saccharomyces cerevisiae to study human S100A8 and S100A9 aggregation and toxicity. We found that S100A8, S100A9 and S100A8/9 cotransfomants form SDS-resistant non-toxic aggregates in yeast cells. Using fluorescently tagged proteins, we showed that S100A8 and S100A9 accumulate in foci. After prolonged induction, S100A8 foci localized to the cell vacuole, whereas the S100A9 foci remained in the cytoplasm when present alone, but entered the vacuole in cotransformants. Biochemical analysis of the proteins indicated that S100A8 and S100A9 alone or coexpressed together form amyloid-like aggregates in yeast. Expression of S100A8 and S100A9 in wild type yeast did not affect cell viability, but these proteins were toxic when expressed on a background of unrelated metastable temperature-sensitive mutant proteins, Cdc53-1p, Cdc34-2p, Srp1-31p and Sec27-1p. This finding suggests that the expression and aggregation of S100A8 and S100A9 may limit the capacity of the cellular proteostasis machinery. To test this hypothesis, we screened a set of chaperone deletion mutants and found that reducing the levels of the heat-shock proteins Hsp104p and Hsp70p was sufficient to induce S100A8 and S100A9 toxicity. This result indicates that the chaperone activity of the Hsp104/Hsp70 bi-chaperone system in wild type cells is sufficient to reduce S100A8 and S100A9 amyloid toxicity and preserve cellular proteostasis. Expression of human S100A8 and S100A9 in yeast thus provides a novel model system for the study of the interaction of amyloid deposits with the proteostasis machinery.
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Affiliation(s)
- Ekaterina Eremenko
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Anat Ben-Zvi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- * E-mail: (AB); (DR)
| | | | - Dina Raveh
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- * E-mail: (AB); (DR)
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Marzo L, Marijanovic Z, Browman D, Chamoun Z, Caputo A, Zurzolo C. 4-hydroxytamoxifen leads to PrPSc clearance by conveying both PrPC and PrPSc to lysosomes independently of autophagy. J Cell Sci 2013; 126:1345-54. [PMID: 23418355 DOI: 10.1242/jcs.114801] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Prion diseases are fatal neurodegenerative disorders involving the abnormal folding of a native cellular protein, named PrP(C), to a malconformed aggregation-prone state, enriched in beta sheet secondary structure, denoted PrP(Sc). Recently, autophagy has garnered considerable attention as a cellular process with the potential to counteract neurodegenerative diseases of protein aggregation such as Alzheimer's disease, Huntington's disease, and Parkinson's disease. Stimulation of autophagy by chemical compounds has also been shown to reduce PrP(Sc) in infected neuronal cells and prolong survival times in mouse models. Consistent with previous reports, we demonstrate that autophagic flux is increased in chronically infected cells. However, in contrast to recent findings we show that autophagy does not cause a reduction in scrapie burden. We report that in infected neuronal cells different compounds known to stimulate autophagy are ineffective in increasing autophagic flux and in reducing PrP(Sc). We further demonstrate that tamoxifen and its metabolite 4-hydroxytamoxifen lead to prion degradation in an autophagy-independent manner by diverting the trafficking of both PrP and cholesterol to lysosomes. Our data indicate that tamoxifen, a well-characterized, widely available pharmaceutical, may have applications in the therapy of prion diseases.
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Affiliation(s)
- Ludovica Marzo
- Institut Pasteur, Unité de Trafic Membranaire et Pathogenèse, 25 rue du Docteur Roux, 75015 Paris, France
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Tsvetkov AS, Ando DM, Finkbeiner S. Longitudinal imaging and analysis of neurons expressing polyglutamine-expanded proteins. Methods Mol Biol 2013; 1017:1-20. [PMID: 23719904 DOI: 10.1007/978-1-62703-438-8_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Misfolded proteins have been implicated in most of the major neurodegenerative diseases, and identifying drugs and pathways that protect neurons from the toxicity of misfolded proteins is of paramount importance. We invented a form of automated imaging and analysis called robotic microscopy that is well suited to the study of neurodegeneration. It enables the monitoring of large cohorts of individual neurons over their lifetimes as they undergo neurodegeneration. With automated analysis, multiple endpoints in neurons can be measured, including survival. Statistical approaches, typically reserved for engineering and clinical medicine, can be applied to these data in an unbiased fashion to discover whether factors contribute positively or negatively to neuronal fate and to quantify the importance of their contribution. Ultimately, multivariate dynamic models can be constructed from these data, which can provide a systems-level understanding of the neurodegenerative disease process and guide the rationale for the development of therapies.
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The Ubiquitin-Proteasome System in Huntington's Disease: Are Proteasomes Impaired, Initiators of Disease, or Coming to the Rescue? Biochem Res Int 2012; 2012:837015. [PMID: 23050151 PMCID: PMC3462393 DOI: 10.1155/2012/837015] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/14/2012] [Accepted: 08/19/2012] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease is a progressive neurodegenerative disease, caused by a polyglutamine expansion in the huntingtin protein. A prominent hallmark of the disease is the presence of intracellular aggregates initiated by N-terminal huntingtin fragments containing the polyglutamine repeat, which recruit components of the ubiquitin-proteasome system. While it is commonly thought that proteasomes are irreversibly sequestered into these aggregates leading to impairment of the ubiquitin-proteasome system, the data on proteasomal impairment in Huntington's disease is contradictory. In addition, it has been suggested that proteasomes are unable to actually cleave polyglutamine sequences in vitro, thereby releasing aggregation-prone polyglutamine peptides in cells. Here, we discuss how the proteasome is involved in the various stages of polyglutamine aggregation in Huntington's disease, and how alterations in activity may improve clearance of mutant huntingtin fragments.
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Baptista MS, Duarte CB, Maciel P. Role of the ubiquitin-proteasome system in nervous system function and disease: using C. elegans as a dissecting tool. Cell Mol Life Sci 2012; 69:2691-715. [PMID: 22382927 PMCID: PMC11115168 DOI: 10.1007/s00018-012-0946-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 02/13/2012] [Accepted: 02/15/2012] [Indexed: 01/12/2023]
Abstract
In addition to its central roles in protein quality control, regulation of cell cycle, intracellular signaling, DNA damage response and transcription regulation, the ubiquitin-proteasome system (UPS) plays specific roles in the nervous system, where it contributes to precise connectivity through development, and later assures functionality by regulating a wide spectrum of neuron-specific cellular processes. Aberrations in this system have been implicated in the etiology of neurodevelopmental and neurodegenerative diseases. In this review, we provide an updated view on the UPS and highlight recent findings concerning its role in normal and diseased nervous systems. We discuss the advantages of the model organism Caenorhabditis elegans as a tool to unravel the major unsolved questions concerning this biochemical pathway and its involvement in nervous system function and dysfunction, and expose the new possibilities, using state-of-the-art techniques, to assess UPS function using this model system.
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Affiliation(s)
- Márcio S Baptista
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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Skibinski GA, Boyd L. Ubiquitination is involved in secondary growth, not initial formation of polyglutamine protein aggregates in C. elegans. BMC Cell Biol 2012; 13:10. [PMID: 22494772 PMCID: PMC3368771 DOI: 10.1186/1471-2121-13-10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 04/11/2012] [Indexed: 11/13/2022] Open
Abstract
Background Protein misfolding and subsequent aggregation are hallmarks of several human diseases. The cell has a variety of mechanisms for coping with misfolded protein stress, including ubiquitin-mediated protein degradation. In fact, the presence of ubiquitin at protein aggregates is a common feature of protein misfolding diseases. Ubiquitin conjugating enzymes (UBCs) are part of the cascade of enzymes responsible for the regulated attachment of ubiquitin to protein substrates. The specific UBC used during ubiquitination can determine the type of polyubiquitin chain linkage, which in turn plays an important role in determining the fate of the ubiquitinated protein. Thus, UBCs may serve an important role in the cellular response to misfolded proteins and the fate of protein aggregates. Results The Q82 strain of C. elegans harbors a transgene encoding an aggregation prone tract of 82 glutamine residues fused to green fluorescent protein (Q82::GFP) that is expressed in the body wall muscle. When measured with time-lapse microscopy in young larvae, the initial formation of individual Q82::GFP aggregates occurs in approximately 58 minutes. This process is largely unaffected by a mutation in the C. elegans E1 ubiquitin activating enzyme. RNAi of ubc-22, a nematode homolog of E2-25K, resulted in higher pre-aggregation levels of Q82::GFP and a faster initial aggregation rate relative to control. Knockdown of ubc-1 (RAD6 homolog), ubc-13, and uev-1 did not affect the kinetics of initial aggregation. However, RNAi of ubc-13 decreases the rate of secondary growth of the aggregate. This result is consistent with previous findings that aggregates in young adult worms are smaller after ubc-13 RNAi. mCherry::ubiquitin becomes localized to Q82::GFP aggregates during the fourth larval (L4) stage of life, a time point long after most aggregates have formed. FLIP and FRAP analysis indicate that mCherry::ubiquitin is considerably more mobile than Q82::GFP within aggregates. Conclusions These data indicate that initial formation of Q82::GFP aggregates in C. elegans is not directly dependent on ubiquitination, but is more likely a spontaneous process driven by biophysical properties in the cytosol such as the concentration of the aggregating species. The effect of ubiquitination appears to be most significant in later, secondary aggregate growth.
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Affiliation(s)
- Gregory A Skibinski
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville AL 35899, USA.
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