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Kinger S, Jagtap YA, Kumar P, Choudhary A, Prasad A, Prajapati VK, Kumar A, Mehta G, Mishra A. Proteostasis in neurodegenerative diseases. Adv Clin Chem 2024; 121:270-333. [PMID: 38797543 DOI: 10.1016/bs.acc.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Proteostasis is essential for normal function of proteins and vital for cellular health and survival. Proteostasis encompasses all stages in the "life" of a protein, that is, from translation to functional performance and, ultimately, to degradation. Proteins need native conformations for function and in the presence of multiple types of stress, their misfolding and aggregation can occur. A coordinated network of proteins is at the core of proteostasis in cells. Among these, chaperones are required for maintaining the integrity of protein conformations by preventing misfolding and aggregation and guide those with abnormal conformation to degradation. The ubiquitin-proteasome system (UPS) and autophagy are major cellular pathways for degrading proteins. Although failure or decreased functioning of components of this network can lead to proteotoxicity and disease, like neuron degenerative diseases, underlying factors are not completely understood. Accumulating misfolded and aggregated proteins are considered major pathomechanisms of neurodegeneration. In this chapter, we have described the components of three major branches required for proteostasis-chaperones, UPS and autophagy, the mechanistic basis of their function, and their potential for protection against various neurodegenerative conditions, like Alzheimer's, Parkinson's, and Huntington's disease. The modulation of various proteostasis network proteins, like chaperones, E3 ubiquitin ligases, proteasome, and autophagy-associated proteins as therapeutic targets by small molecules as well as new and unconventional approaches, shows promise.
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Affiliation(s)
- Sumit Kinger
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India
| | - Yuvraj Anandrao Jagtap
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India
| | - Prashant Kumar
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India
| | - Akash Choudhary
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India
| | - Amit Prasad
- School of Biosciences and Bioengineering, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, Madhya Pradesh, India
| | - Gunjan Mehta
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India.
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2
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Geijtenbeek KW, Aranda AS, Sanz AS, Janzen J, Bury AE, Kors S, Al Amery N, Schmitz NCM, Reits EAJ, Schipper-Krom S. Insulin-Degrading Enzyme Efficiently Degrades polyQ Peptides but not Expanded polyQ Huntingtin Fragments. J Huntingtons Dis 2024; 13:201-214. [PMID: 38640164 DOI: 10.3233/jhd-230583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
Background Huntington's disease is an inheritable autosomal dominant disorder caused by an expanded CAG trinucleotide repeat within the Huntingtin gene, leading to a polyglutamine (polyQ) expansion in the mutant protein. Objective A potential therapeutic approach for delaying or preventing the onset of the disease involves enhancing the degradation of the aggregation-prone polyQ-expanded N-terminal mutant huntingtin (mHTT) exon1 fragment. A few proteases and peptidases have been identified that are able to cleave polyQ fragments with low efficiency. This study aims to identify a potent polyQ-degrading endopeptidase. Methods Here we used quenched polyQ peptides to identify a polyQ-degrading endopeptidase. Next we investigated its role on HTT turnover, using purified polyQ-expanded HTT fragments and striatal cells expressing mHTT exon1 peptides. Results We identified insulin-degrading enzyme (IDE) as a novel endopeptidase for degrading polyQ peptides. IDE was, however, ineffective in reducing purified polyQ-expanded HTT fragments. Similarly, in striatal cells expressing mHTT exon1 peptides, IDE did not enhance mHTT turnover. Conclusions This study shows that despite IDE's efficiency in degrading polyQ peptides, it does not contribute to the direct degradation of polyQ-expanded mHTT fragments.
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Affiliation(s)
- Karlijne W Geijtenbeek
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Angela Santiago Aranda
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Alicia Sanz Sanz
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Jolien Janzen
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Aleksandra E Bury
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Suzan Kors
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | | | - Nina C M Schmitz
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Eric A J Reits
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Sabine Schipper-Krom
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
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3
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Hasholt LF. Upregulated Chaperone-Mediated Autophagy May Perform a Key Role in Reduced Cancer Incidence in Huntington's Disease. J Huntingtons Dis 2023; 12:371-376. [PMID: 37927269 PMCID: PMC11091607 DOI: 10.3233/jhd-230586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2023] [Indexed: 11/07/2023]
Abstract
Incidence of cancer is markedly reduced in patients with the hereditary neurodegenerative polyglutamine (polyQ) diseases. We have very poor knowledge of the underlying molecular mechanisms, but the expanded polyQ sequence is assumed to play a central role, because it is common to the respective disease related proteins. The inhibition seems to take place in all kinds of cells, because the lower cancer frequency applies to nearly all types of tumors and is not related with the characteristic pathological changes in specific brain tissues. Further, the cancer repressing mechanisms appear to be active early in life including in pre-symptomatic and early phase polyQ patients. Autophagy plays a central role in clearing proteins with expanded polyQ tracts, and autophagy modulation has been demonstrated and particularly investigated in Huntington's disease (HD). Macroautophagy may be dysfunctional due to defects in several steps of the process, whereas increased chaperone-mediated autophagy (CMA) has been shown in HD patients, cell and animal models. Recently, CMA is assumed to play a key role in prevention of cellular transformation of normal cells into cancer cells. Investigations of normal cells from HD and other polyQ carriers could therefore add further insight into the protective mechanisms of CMA in tumorigenesis, and be important for development of autophagy based strategies to prevent malignant processes leading to cancer and neurodegeneration.
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Sap KA, Geijtenbeek KW, Schipper-Krom S, Guler AT, Reits EA. Ubiquitin-modifying enzymes in Huntington's disease. Front Mol Biosci 2023; 10:1107323. [PMID: 36926679 PMCID: PMC10013475 DOI: 10.3389/fmolb.2023.1107323] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/16/2023] [Indexed: 02/10/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the N-terminus of the HTT gene. The CAG repeat expansion translates into a polyglutamine expansion in the mutant HTT (mHTT) protein, resulting in intracellular aggregation and neurotoxicity. Lowering the mHTT protein by reducing synthesis or improving degradation would delay or prevent the onset of HD, and the ubiquitin-proteasome system (UPS) could be an important pathway to clear the mHTT proteins prior to aggregation. The UPS is not impaired in HD, and proteasomes can degrade mHTT entirely when HTT is targeted for degradation. However, the mHTT protein is differently ubiquitinated when compared to wild-type HTT (wtHTT), suggesting that the polyQ expansion affects interaction with (de) ubiquitinating enzymes and subsequent targeting for degradation. The soluble mHTT protein is associated with several ubiquitin-modifying enzymes, and various ubiquitin-modifying enzymes have been identified that are linked to Huntington's disease, either by improving mHTT turnover or affecting overall homeostasis. Here we describe their potential mechanism of action toward improved mHTT targeting towards the proteostasis machinery.
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Affiliation(s)
- Karen A Sap
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Karlijne W Geijtenbeek
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Sabine Schipper-Krom
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Arzu Tugce Guler
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Eric A Reits
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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5
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Geijtenbeek KW, Janzen J, Bury AE, Sanz-Sanz A, Hoebe RA, Bondulich MK, Bates GP, Reits EAJ, Schipper-Krom S. Reduction in PA28αβ activation in HD mouse brain correlates to increased mHTT aggregation in cell models. PLoS One 2022; 17:e0278130. [PMID: 36574405 PMCID: PMC9794069 DOI: 10.1371/journal.pone.0278130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 11/09/2022] [Indexed: 12/29/2022] Open
Abstract
Huntington's disease is an autosomal dominant heritable disorder caused by an expanded CAG trinucleotide repeat at the N-terminus of the Huntingtin (HTT) gene. Lowering the levels of soluble mutant HTT protein prior to aggregation through increased degradation by the proteasome would be a therapeutic strategy to prevent or delay the onset of disease. Native PAGE experiments in HdhQ150 mice and R6/2 mice showed that PA28αβ disassembles from the 20S proteasome during disease progression in the affected cortex, striatum and hippocampus but not in cerebellum and brainstem. Modulating PA28αβ activated proteasomes in various in vitro models showed that PA28αβ improved polyQ degradation, but decreased the turnover of mutant HTT. Silencing of PA28αβ in cells lead to an increase in mutant HTT aggregates, suggesting that PA28αβ is critical for overall proteostasis, but only indirectly affects mutant HTT aggregation.
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Affiliation(s)
| | - Jolien Janzen
- Amsterdam UMC Location University of Amsterdam, Medical Biology, Amsterdam, The Netherlands
| | - Aleksandra E. Bury
- Amsterdam UMC Location University of Amsterdam, Medical Biology, Amsterdam, The Netherlands
| | - Alicia Sanz-Sanz
- Amsterdam UMC Location University of Amsterdam, Medical Biology, Amsterdam, The Netherlands
| | - Ron A. Hoebe
- Amsterdam UMC Location University of Amsterdam, Medical Biology, Amsterdam, The Netherlands
| | - Marie K. Bondulich
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London, United Kingdom
| | - Gillian P. Bates
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London, United Kingdom
| | - Eric A. J. Reits
- Amsterdam UMC Location University of Amsterdam, Medical Biology, Amsterdam, The Netherlands
- * E-mail:
| | - Sabine Schipper-Krom
- Amsterdam UMC Location University of Amsterdam, Medical Biology, Amsterdam, The Netherlands
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6
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Roy PK, Biswas A, Deepak K, Mandal M. An insight into the ubiquitin-proteasomal axis and related therapeutic approaches towards central nervous system malignancies. Biochim Biophys Acta Rev Cancer 2022; 1877:188734. [PMID: 35489645 DOI: 10.1016/j.bbcan.2022.188734] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/12/2022] [Accepted: 04/22/2022] [Indexed: 10/18/2022]
Abstract
The Ubiquitin-Protease system (UPS) is a major destruction system that is responsible for the elimination of dysfunctional/misfolded proteins, thus acting as a pivotal regulator of protein homeostasis in eukaryotic cells. In this review, the UPS system and its various functions in the cell and their detailed impact such as cell cycle control, DNA damage response, apoptosis, and cellular stress regulations have been elucidated with a focus on the central nervous system. Since the Ubiquitin-Protease pathway(UPP) plays a prominent role in the sculpting of the CNS cells and their maintenance, it is naturally deeply involved in many malignancies that develop due to dysregulation of the UPS. Understanding the major disruptive players of the UPS in the development of these malignancies, for example, insoluble protein aggregates or inclusion bodies deposits due to malfunctioning of the UPS has paved the pathway for the development of new therapeutics. Here, the de-regulation of the UPS at various checkpoints in CNS malignancies has been detailed, thus facilitating an easy comprehension of the different targets that remain to be explored yet. The present therapeutic advancements in the field of CNS malignancies management through UPS targeting have also been included thus broadening the scope of drug development. Thus, this review while shedding sufficient light on the details of the UPS system and its connection to CNS malignancies, also opens new avenues for therapeutic advancements in the form of novel targetable UPP proteins and their interactions.
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Affiliation(s)
- Pritam Kumar Roy
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Angana Biswas
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - K Deepak
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India..
| | - Mahitosh Mandal
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, West Bengal 721302, India..
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7
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Nuclear and cytoplasmic huntingtin inclusions exhibit distinct biochemical composition, interactome and ultrastructural properties. Nat Commun 2021; 12:6579. [PMID: 34772920 PMCID: PMC8589980 DOI: 10.1038/s41467-021-26684-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/11/2021] [Indexed: 12/20/2022] Open
Abstract
Despite the strong evidence linking the aggregation of the Huntingtin protein (Htt) to the pathogenesis of Huntington's disease (HD), the mechanisms underlying Htt aggregation and neurodegeneration remain poorly understood. Herein, we investigated the ultrastructural properties and protein composition of Htt cytoplasmic and nuclear inclusions in mammalian cells and primary neurons overexpressing mutant exon1 of the Htt protein. Our findings provide unique insight into the ultrastructural properties of cytoplasmic and nuclear Htt inclusions and their mechanisms of formation. We show that Htt inclusion formation and maturation are complex processes that, although initially driven by polyQ-dependent Htt aggregation, also involve the polyQ and PRD domain-dependent sequestration of lipids and cytoplasmic and cytoskeletal proteins related to HD dysregulated pathways; the recruitment and accumulation of remodeled or dysfunctional membranous organelles, and the impairment of the protein quality control and degradation machinery. We also show that nuclear and cytoplasmic Htt inclusions exhibit distinct biochemical compositions and ultrastructural properties, suggesting different mechanisms of aggregation and toxicity.
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8
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The Cytotoxicity and Clearance of Mutant Huntingtin and Other Misfolded Proteins. Cells 2021; 10:cells10112835. [PMID: 34831058 PMCID: PMC8616338 DOI: 10.3390/cells10112835] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 02/07/2023] Open
Abstract
Protein misfolding and aggregation are implicated in many neurodegenerative diseases. One of these diseases is Huntington's, which is caused by increased glutamine-encoding trinucleotide repeats within the Huntingtin gene. Like other misfolded proteins, mutated Huntingtin proteins with polyglutamine expansions are prone to aggregation. Misfolded proteins exist as soluble monomers, small aggregates, or as large insoluble inclusion bodies. Misfolded protein aggregates are believed to be cytotoxic by stressing the protein degradation machinery, disrupting membrane structure, or sequestering other proteins. We recently showed that expression of misfolded proteins lowers cellular free ubiquitin levels, which compromises the protein degradation machinery. Therefore, the efficient degradation of misfolded proteins is critical to preserve cell health. Cells employ two major mechanisms to degrade misfolded proteins. The first is the ubiquitin-proteasome system (UPS), which ubiquitinates and degrades misfolded proteins with the assistance of segregase Cdc48/p97. The UPS pathway is mainly responsible for the clearance of misfolded proteins present as monomers or smaller aggregates. The second pathway is macroautophagy/autophagy, in which protein aggregates or inclusion bodies are recruited into an autophagosome before transport to the vacuole/lysosome for degradation. This review is focused on the current understanding of the cytotoxicity of misfolded proteins as well as their clearance pathways, with a particular emphasis on mutant Huntingtin.
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9
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Račková L, Csekes E. Proteasome Biology: Chemistry and Bioengineering Insights. Polymers (Basel) 2020; 12:E2909. [PMID: 33291646 PMCID: PMC7761984 DOI: 10.3390/polym12122909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022] Open
Abstract
Proteasomal degradation provides the crucial machinery for maintaining cellular proteostasis. The biological origins of modulation or impairment of the function of proteasomal complexes may include changes in gene expression of their subunits, ubiquitin mutation, or indirect mechanisms arising from the overall impairment of proteostasis. However, changes in the physico-chemical characteristics of the cellular environment might also meaningfully contribute to altered performance. This review summarizes the effects of physicochemical factors in the cell, such as pH, temperature fluctuations, and reactions with the products of oxidative metabolism, on the function of the proteasome. Furthermore, evidence of the direct interaction of proteasomal complexes with protein aggregates is compared against the knowledge obtained from immobilization biotechnologies. In this regard, factors such as the structures of the natural polymeric scaffolds in the cells, their content of reactive groups or the sequestration of metal ions, and processes at the interface, are discussed here with regard to their influences on proteasomal function.
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Affiliation(s)
- Lucia Račková
- Centre of Experimental Medicine, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia;
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10
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Masnata M, Salem S, de Rus Jacquet A, Anwer M, Cicchetti F. Targeting Tau to Treat Clinical Features of Huntington's Disease. Front Neurol 2020; 11:580732. [PMID: 33329322 PMCID: PMC7710872 DOI: 10.3389/fneur.2020.580732] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/17/2020] [Indexed: 12/16/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by severe motor, cognitive and psychiatric impairments. While motor deficits often confirm diagnosis, cognitive dysfunctions usually manifest early in the disease process and are consistently ranked among the leading factors that impact the patients' quality of life. The genetic component of HD, a mutation in the huntingtin (HTT) gene, is traditionally presented as the main contributor to disease pathology. However, accumulating evidence suggests the implication of the microtubule-associated tau protein to the pathogenesis and therefore, proposes an alternative conceptual framework where tau and mutant huntingtin (mHTT) act conjointly to drive neurodegeneration and cognitive dysfunction. This perspective on disease etiology offers new avenues to design therapeutic interventions and could leverage decades of research on Alzheimer's disease (AD) and other tauopathies to rapidly advance drug discovery. In this mini review, we examine the breadth of tau-targeting treatments currently tested in the preclinical and clinical settings for AD and other tauopathies, and discuss the potential application of these strategies to HD.
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Affiliation(s)
- Maria Masnata
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada
| | - Shireen Salem
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada
| | - Aurelie de Rus Jacquet
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada
| | - Mehwish Anwer
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada
| | - Francesca Cicchetti
- Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada.,Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada
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11
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Le Guerroué F, Youle RJ. Ubiquitin signaling in neurodegenerative diseases: an autophagy and proteasome perspective. Cell Death Differ 2020; 28:439-454. [PMID: 33208890 DOI: 10.1038/s41418-020-00667-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 12/13/2022] Open
Abstract
Ubiquitin signaling is a sequence of events driving the fate of a protein based on the type of ubiquitin modifications attached. In the case of neurodegenerative diseases, ubiquitin signaling is mainly associated with degradation signals to process aberrant proteins, which form aggregates often fatal for the brain cells. This signaling is often perturbed by the aggregates themselves and leads to the accumulation of toxic aggregates and inclusion bodies that are deleterious due to a toxic gain of function. Decrease in quality control pathways is often seen with age and is a critical onset for the development of neurodegeneration. Many aggregates are now thought to propagate in a prion-like manner, where mutated proteins acting like seeds are transitioning from cell to cell, converting normal proteins to toxic aggregates. Modulation of ubiquitin signaling, by stimulating ubiquitin ligase activation, is a potential therapeutic strategy to treat patients with neurodegeneration diseases.
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Affiliation(s)
- François Le Guerroué
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Richard J Youle
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
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12
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Kim YM, Kim HJ. Proteasome Inhibitor MG132 is Toxic and Inhibits the Proliferation of Rat Neural Stem Cells but Increases BDNF Expression to Protect Neurons. Biomolecules 2020; 10:biom10111507. [PMID: 33147870 PMCID: PMC7692322 DOI: 10.3390/biom10111507] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/21/2020] [Accepted: 10/27/2020] [Indexed: 12/31/2022] Open
Abstract
Regulation of protein expression is essential for maintaining normal cell function. Proteasomes play important roles in protein degradation and dysregulation of proteasomes is implicated in neurodegenerative disorders. In this study, using a proteasome inhibitor MG132, we showed that proteasome inhibition reduces neural stem cell (NSC) proliferation and is toxic to NSCs. Interestingly, MG132 treatment increased the percentage of neurons in both proliferation and differentiation culture conditions of NSCs. Proteasome inhibition reduced B-cell lymphoma 2 (Bcl-2)/Bcl-2 associated X protein ratio. In addition, MG132 treatment induced cAMP response element-binding protein phosphorylation and increased the expression of brain-derived neurotrophic factor transcripts and proteins. These data suggest that proteasome function is important for NSC survival and differentiation. Moreover, although MG132 is toxic to NSCs, it may increase neurogenesis. Therefore, by modifying MG132 chemical structure and developing none toxic proteasome inhibitors, neurogenic chemicals can be developed to control NSC cell fate.
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Affiliation(s)
| | - Hyun-Jung Kim
- Correspondence: ; Tel.: +82-2-820-5619; Fax: +82-2-816-7338
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13
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Celebi G, Kesim H, Ozer E, Kutlu O. The Effect of Dysfunctional Ubiquitin Enzymes in the Pathogenesis of Most Common Diseases. Int J Mol Sci 2020; 21:ijms21176335. [PMID: 32882786 PMCID: PMC7503467 DOI: 10.3390/ijms21176335] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/17/2020] [Accepted: 07/18/2020] [Indexed: 12/14/2022] Open
Abstract
Ubiquitination is a multi-step enzymatic process that involves the marking of a substrate protein by bonding a ubiquitin and protein for proteolytic degradation mainly via the ubiquitin–proteasome system (UPS). The process is regulated by three main types of enzymes, namely ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), and ubiquitin ligases (E3). Under physiological conditions, ubiquitination is highly reversible reaction, and deubiquitinases or deubiquitinating enzymes (DUBs) can reverse the effect of E3 ligases by the removal of ubiquitin from substrate proteins, thus maintaining the protein quality control and homeostasis in the cell. The dysfunction or dysregulation of these multi-step reactions is closely related to pathogenic conditions; therefore, understanding the role of ubiquitination in diseases is highly valuable for therapeutic approaches. In this review, we first provide an overview of the molecular mechanism of ubiquitination and UPS; then, we attempt to summarize the most common diseases affecting the dysfunction or dysregulation of these mechanisms.
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Affiliation(s)
- Gizem Celebi
- Faculty of Engineering and Natural Sciences, Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, Istanbul 34956, Turkey; (G.C.); (H.K.); (E.O.)
| | - Hale Kesim
- Faculty of Engineering and Natural Sciences, Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, Istanbul 34956, Turkey; (G.C.); (H.K.); (E.O.)
| | - Ebru Ozer
- Faculty of Engineering and Natural Sciences, Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, Istanbul 34956, Turkey; (G.C.); (H.K.); (E.O.)
| | - Ozlem Kutlu
- Sabanci University Nanotechnology Research and Application Center (SUNUM), Istanbul 34956, Turkey
- Center of Excellence for Functional Surfaces and Interfaces for Nano Diagnostics (EFSUN), Sabanci University, Istanbul 34956, Turkey
- Correspondence: ; Tel.: +90-216-483-9000 (ext. 2413)
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14
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Morrow CS, Porter TJ, Xu N, Arndt ZP, Ako-Asare K, Heo HJ, Thompson EAN, Moore DL. Vimentin Coordinates Protein Turnover at the Aggresome during Neural Stem Cell Quiescence Exit. Cell Stem Cell 2020; 26:558-568.e9. [PMID: 32109376 DOI: 10.1016/j.stem.2020.01.018] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/31/2019] [Accepted: 01/23/2020] [Indexed: 01/08/2023]
Abstract
Maintaining a healthy proteome throughout life is critical for proper somatic stem cell function, but the complexities of the stem cell response to increases in damaged or aggregated proteins remain unclear. Here we demonstrate that adult neural stem cells (NSCs) utilize aggresomes to recover from disrupted proteostasis and describe a novel function for the intermediate filament vimentin in proteostasis as a spatial coordinator of proteasomes to the aggresome. In the absence of vimentin, NSCs have a reduced capacity to exit quiescence, a time when NSCs are required to clear a wave of aggregated proteins, and demonstrate an early age-dependent decline in proliferation and neurogenesis. Taken together, these data reveal a significant role of vimentin and aggresomes in the regulation of proteostasis during quiescent NSC activation.
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Affiliation(s)
- Christopher S Morrow
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Tiaira J Porter
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Nan Xu
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Zachary P Arndt
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Kayla Ako-Asare
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Helen J Heo
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53705, USA
| | | | - Darcie L Moore
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53705, USA.
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15
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Schipper-Krom S, Sanz AS, van Bodegraven EJ, Speijer D, Florea BI, Ovaa H, Reits EA. Visualizing Proteasome Activity and Intracellular Localization Using Fluorescent Proteins and Activity-Based Probes. Front Mol Biosci 2019; 6:56. [PMID: 31482094 PMCID: PMC6710370 DOI: 10.3389/fmolb.2019.00056] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/02/2019] [Indexed: 12/18/2022] Open
Abstract
The proteasome is a multi-catalytic molecular machine that plays a key role in the degradation of many cytoplasmic and nuclear proteins. The proteasome is essential and proteasome malfunction is associated with various disease pathologies. Proteasome activity depends on its catalytic subunits which are interchangeable and also on the interaction with the associated regulatory cap complexes. Here, we describe and compare various methods that allow the study of proteasome function in living cells. Methods include the use of fluorescently tagged proteasome subunits and the use of activity-based proteasome probes. These probes can be used in both biochemical assays and in microscopy-based experiments. Together with tagged proteasomes, they can be used to study proteasome localization, dynamics, and activity.
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Affiliation(s)
- Sabine Schipper-Krom
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Alicia Sanz Sanz
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Emma J. van Bodegraven
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Dave Speijer
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Bogdan I. Florea
- Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
| | - Huib Ovaa
- Department of Cell and Chemical Biology, Leiden University Medical Center, Oncode Institute, Leiden, Netherlands
| | - Eric A. Reits
- Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
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16
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Luo H, Han L, Xu J. Apelin/APJ system: A novel promising target for neurodegenerative diseases. J Cell Physiol 2019; 235:638-657. [DOI: 10.1002/jcp.29001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 06/06/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Huaiqing Luo
- Department of Physiology Changsha Medical University Changsha Hunan China
- Department of Physiology, School of Basic Medical Science Central South University Changsha Hunan China
| | - Li Han
- Department of Physiology Changsha Medical University Changsha Hunan China
| | - Jin Xu
- School of Pharmaceutical Sciences Changsha Medical University Changsha Hunan China
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17
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Gan J, Leestemaker Y, Sapmaz A, Ovaa H. Highlighting the Proteasome: Using Fluorescence to Visualize Proteasome Activity and Distribution. Front Mol Biosci 2019; 6:14. [PMID: 30968028 PMCID: PMC6438883 DOI: 10.3389/fmolb.2019.00014] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/01/2019] [Indexed: 11/30/2022] Open
Abstract
Proteasomes are critical proteases in the cell responsible for the turnover of many cytoplasmic and nuclear proteins. They are essential for many cellular processes and various diseases are associated with their malfunctioning. Proteasome activity depends on the nature of the catalytic subunits, as well as the interaction with associated proteasome regulators. Here we describe various fluorescence-based methods to study proteasome function, highlighting the use of activity-based probes to study proteasome localization, dynamics, and activity in living cells.
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Affiliation(s)
- Jin Gan
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Centre, Leiden, Netherlands
| | - Yves Leestemaker
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Centre, Leiden, Netherlands
| | - Aysegul Sapmaz
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Centre, Leiden, Netherlands
| | - Huib Ovaa
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Centre, Leiden, Netherlands
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18
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Croce KR, Yamamoto A. A role for autophagy in Huntington's disease. Neurobiol Dis 2018; 122:16-22. [PMID: 30149183 DOI: 10.1016/j.nbd.2018.08.010] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 08/10/2018] [Accepted: 08/23/2018] [Indexed: 12/19/2022] Open
Abstract
The lysosome-mediated degradation pathway known as macroautophagy is the most versatile means through which cells can eliminate and recycle unwanted materials. Through both selective and non-selective means, macroautophagy can degrade a wide range of cargoes from bulk cytosol to organelles and aggregated proteins. Although studies of disorders such as Parkinson's disease and Amyotrophic Lateral Sclerosis suggest that autophagic and lysosomal dysfunction directly contributes to disease, this had not been the case for the polyglutamine disorder Huntington's disease (HD), for which there was little indication of a disruption in the autophagic-lysosomal system. This supported the possibility of targeting autophagy as a much needed therapeutic approach to combat this disease. Possibly challenging this view, however, are a recent set of studies suggesting that the protein affected in Huntington's disease, huntingtin, might mechanistically contribute to macroautophagy. In this review, we will explore how autophagy might impact or be impacted by HD pathogenesis, and whether a therapeutic approach centering on autophagy may be possible for this yet incurable disease.
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Affiliation(s)
- Katherine R Croce
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, United States
| | - Ai Yamamoto
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, United States; Department of Neurology, Columbia University, New York, NY 10032, United States.
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19
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Harding RJ, Tong YF. Proteostasis in Huntington's disease: disease mechanisms and therapeutic opportunities. Acta Pharmacol Sin 2018; 39:754-769. [PMID: 29620053 DOI: 10.1038/aps.2018.11] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 02/18/2018] [Indexed: 02/08/2023] Open
Abstract
Many neurodegenerative diseases are characterized by impairment of protein quality control mechanisms in neuronal cells. Ineffective clearance of misfolded proteins by the proteasome, autophagy pathways and exocytosis leads to accumulation of toxic protein oligomers and aggregates in neurons. Toxic protein species affect various cellular functions resulting in the development of a spectrum of different neurodegenerative proteinopathies, including Huntington's disease (HD). Playing an integral role in proteostasis, dysfunction of the ubiquitylation system in HD is progressive and multi-faceted with numerous biochemical pathways affected, in particular, the ubiquitin-proteasome system and autophagy routes for protein aggregate degradation. Unravelling the molecular mechanisms involved in HD pathogenesis of proteostasis provides new insight in disease progression in HD as well as possible therapeutic avenues. Recent developments of potential therapeutics are discussed in this review.
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20
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Posey AE, Ruff KM, Harmon TS, Crick SL, Li A, Diamond MI, Pappu RV. Profilin reduces aggregation and phase separation of huntingtin N-terminal fragments by preferentially binding to soluble monomers and oligomers. J Biol Chem 2018; 293:3734-3746. [PMID: 29358329 PMCID: PMC5846159 DOI: 10.1074/jbc.ra117.000357] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/16/2018] [Indexed: 11/06/2022] Open
Abstract
Huntingtin N-terminal fragments (Htt-NTFs) with expanded polyglutamine tracts form a range of neurotoxic aggregates that are associated with Huntington's disease. Here, we show that aggregation of Htt-NTFs, irrespective of polyglutamine length, yields at least three phases (designated M, S, and F) that are delineated by sharp concentration thresholds and distinct aggregate sizes and morphologies. We found that monomers and oligomers make up the soluble M phase, ∼25-nm spheres dominate in the soluble S phase, and long, linear fibrils make up the insoluble F phase. Previous studies showed that profilin, an abundant cellular protein, reduces Htt-NTF aggregation and toxicity in cells. We confirm that profilin achieves its cellular effects through direct binding to the C-terminal proline-rich region of Htt-NTFs. We show that profilin preferentially binds to Htt-NTF M-phase species and destabilizes aggregation and phase separation by shifting the concentration boundaries for phase separation to higher values through a process known as polyphasic linkage. Our experiments, aided by coarse-grained computer simulations and theoretical analysis, suggest that preferential binding of profilin to the M-phase species of Htt-NTFs is enhanced through a combination of specific interactions between profilin and polyproline segments and auxiliary interactions between profilin and polyglutamine tracts. Polyphasic linkage may be a general strategy that cells utilize to regulate phase behavior of aggregation-prone proteins. Accordingly, detailed knowledge of phase behavior and an understanding of how ligands modulate phase boundaries may pave the way for developing new therapeutics against a variety of aggregation-prone proteins.
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Affiliation(s)
- Ammon E Posey
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130
| | - Kiersten M Ruff
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130
| | - Tyler S Harmon
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130
| | - Scott L Crick
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130
| | - Aimin Li
- the Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63108
| | - Marc I Diamond
- the Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | - Rohit V Pappu
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130,
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21
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Dynamic recruitment of ubiquitin to mutant huntingtin inclusion bodies. Sci Rep 2018; 8:1405. [PMID: 29362455 PMCID: PMC5780509 DOI: 10.1038/s41598-018-19538-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/03/2018] [Indexed: 12/02/2022] Open
Abstract
Many neurodegenerative diseases, such as Huntington’s disease, are hallmarked by the formation of intracellular inclusion bodies (IBs) that are decorated with ubiquitin, proteasomes and chaperones. The apparent enrichment of ubiquitin and components involved in protein quality control at IBs suggests local ubiquitin-dependent enzymatic activity. In this study, we examine recruitment of ubiquitin to IBs of polyglutamine-expanded huntingtin fragments (mHtt) by using synthesized TAMRA-labeled ubiquitin moieties. We show that intracellular TAMRA-ubiquitin is dynamic at mHtt IBs and is incorporated into poly-ubiquitin chains of intracellular substrates, such as mHtt, in a conjugation-dependent manner. Furthermore, we report that mHtt IBs recruit catalytically active enzymes involved in (de)-ubiquitination processes based on novel activity-based probes. However, we also find that the overexpression of the GFP-ubiquitin reporter, unlike the endogenous ubiquitin and TAMRA-ubiquitin, becomes irreversibly sequestered as a ring-like structure around the mHtt IBs, suggesting a methodical disadvantage of GFP-tagged ubiquitin. Our data provide supportive evidence for dynamic recruitment of ubiquitin and ubiquitin (de)-conjugating activity at mHtt initiated IBs.
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22
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Vodicka P, Chase K, Iuliano M, Valentine DT, Sapp E, Lu B, Kegel-Gleason KB, Sena-Esteves M, Aronin N, DiFiglia M. Effects of Exogenous NUB1 Expression in the Striatum of HDQ175/Q7 Mice. J Huntingtons Dis 2017; 5:163-74. [PMID: 27314618 DOI: 10.3233/jhd-160195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Reducing mutant huntingtin (mHTT) in neurons may be a therapy for Huntington's disease (HD). Elevating NUB1 protein reduced mHTT levels in cell and fly models of HD through a proteasome dependent mechanism. OBJECTIVE To examine the effects of augmenting NUB1 in HD mouse striatum on mHTT levels. METHODS Striata of HDQ175/Q7 mice were injected at 3 months of age with recombinant AAV2/9 coding for NUB1 or GFP under the control of the neuron specific human synapsin 1 promoter and examined 6 months post-injection for levels of huntingtin, the striatal markers DARPP32 and PDE10A, the astrocyte marker GFAP, and the autophagy and mHTT aggregate marker P62 using immunolabeling of brain sections and Western blot assay of striatal subcellular fractions. RESULTS By Western blot human HD brain had only one of the two variants of NUB1 present in human control brain. In striatum of WT and HD mice NUB1 was localized in medium size neurons and enriched in the nucleus of large neurons. In the striatum of NUB1 injected HD mice, there was widespread neuronal distribution of exogenous NUB1 labeling and protein levels were ∼2.5-fold endogenous levels. DARPP32 and GFAP distribution and levels were unchanged but PDE10A levels were lower in crude homogenates and P62 was increased in nuclear enriched P1 fractions. Elevating NUB1 did not change levels of full-length mHTT or the number and size of mHTT (S830) positive nuclear inclusions. CONCLUSION Findings suggest that increasing NUB1 protein in striatal neurons of HDQ175/Q7 mice in vivo may be relatively safe but is ineffective in reducing mHTT. Increased NUB1 expression in HD striatum alters PDE10A and P62 which are known to be influenced by mHTT.
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Affiliation(s)
- Petr Vodicka
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Kathryn Chase
- Department of Medicine and The RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Maria Iuliano
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Dana T Valentine
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Boxun Lu
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA.,State Key Laboratory of Medical Neurobiology, School of Life Sciences, Fudan University, China
| | - Kimberly B Kegel-Gleason
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Miguel Sena-Esteves
- Department of Neurology, Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
| | - Neil Aronin
- Department of Medicine and The RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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23
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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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24
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The life cycle of the 26S proteasome: from birth, through regulation and function, and onto its death. Cell Res 2016; 26:869-85. [PMID: 27444871 PMCID: PMC4973335 DOI: 10.1038/cr.2016.86] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The 26S proteasome is a large, ∼2.5 MDa, multi-catalytic ATP-dependent protease complex that serves as the degrading arm of the ubiquitin system, which is the major pathway for regulated degradation of cytosolic, nuclear and membrane proteins in all eukaryotic organisms.
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25
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Bersuker K, Brandeis M, Kopito RR. Protein misfolding specifies recruitment to cytoplasmic inclusion bodies. J Cell Biol 2016; 213:229-41. [PMID: 27114501 PMCID: PMC5084276 DOI: 10.1083/jcb.201511024] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 03/21/2016] [Indexed: 12/17/2022] Open
Abstract
Inclusion bodies (IBs) containing aggregated disease-associated proteins and polyubiquitin (poly-Ub) conjugates are universal histopathological features of neurodegenerative diseases. Ub has been proposed to target proteins to IBs for degradation via autophagy, but the mechanisms that govern recruitment of ubiquitylated proteins to IBs are not well understood. In this paper, we use conditionally destabilized reporters that undergo misfolding and ubiquitylation upon removal of a stabilizing ligand to examine the role of Ub conjugation in targeting proteins to IBs that are composed of an N-terminal fragment of mutant huntingtin, the causative protein of Huntington's disease. We show that reporters are excluded from IBs in the presence of the stabilizing ligand but are recruited to IBs after ligand washout. However, we find that Ub conjugation is not necessary to target reporters to IBs. We also report that forced Ub conjugation by the Ub fusion degradation pathway is not sufficient for recruitment to IBs. Finally, we find that reporters and Ub conjugates are stable at IBs. These data indicate that compromised folding states, rather than conjugation to Ub, can specify recruitment to IBs.
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Affiliation(s)
- Kirill Bersuker
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Michael Brandeis
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ron R Kopito
- Department of Biology, Stanford University, Stanford, CA 94305
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26
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Eenjes E, Dragich JM, Kampinga HH, Yamamoto A. Distinguishing aggregate formation and aggregate clearance using cell-based assays. J Cell Sci 2016; 129:1260-70. [PMID: 26818841 DOI: 10.1242/jcs.179978] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 01/21/2016] [Indexed: 01/01/2023] Open
Abstract
The accumulation of ubiquitylated proteinaceous inclusions represents a complex process, reflecting the disequilibrium between aggregate formation and aggregate clearance. Although decreasing aggregate formation or augmenting aggregate clearance will ultimately lead to a diminished aggregate burden, in terms of disease pathogenesis, the different approaches can have distinct outcomes. Using a novel cell-based assay that can distinguish newly formed versus preformed inclusions, we demonstrate that two proteins previously implicated in the autophagic clearance of expanded polyglutamine inclusions, HspB7 and Alfy (also known as WDFY3), actually affect very distinct cellular processes to affect aggregate burden. Using this cell-based assay, we also establish that constitutive expression of the aggregation-prone protein can measurably slow the elimination of protein aggregates, given that not all aggregates appear to be available for degradation. This new assay can therefore not only determine at what step a modifier might influence aggregate burden, but also can be used to provide new insights into how protein aggregates are targeted for degradation.
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Affiliation(s)
- Evelien Eenjes
- Columbia University, Department of Neurology, New York, NY 10032, USA University Medical Center Groningen, University of Groningen, Department of Cell Biology, Groningen 9713, The Netherlands
| | - Joanna M Dragich
- Columbia University, Department of Neurology, New York, NY 10032, USA
| | - Harm H Kampinga
- University Medical Center Groningen, University of Groningen, Department of Cell Biology, Groningen 9713, The Netherlands
| | - Ai Yamamoto
- Columbia University, Department of Neurology, New York, NY 10032, USA Columbia University, Department of Pathology and Cell Biology, New York, NY 10032, USA
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27
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Papaevgeniou N, Chondrogianni N. UPS Activation in the Battle Against Aging and Aggregation-Related Diseases: An Extended Review. Methods Mol Biol 2016; 1449:1-70. [PMID: 27613027 DOI: 10.1007/978-1-4939-3756-1_1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Aging is a biological process accompanied by gradual increase of damage in all cellular macromolecules, i.e., nucleic acids, lipids, and proteins. When the proteostasis network (chaperones and proteolytic systems) cannot reverse the damage load due to its excess as compared to cellular repair/regeneration capacity, failure of homeostasis is established. This failure is a major hallmark of aging and/or aggregation-related diseases. Dysfunction of the major cellular proteolytic machineries, namely the proteasome and the lysosome, has been reported during the progression of aging and aggregation-prone diseases. Therefore, activation of these pathways is considered as a possible preventive or therapeutic approach against the progression of these processes. This chapter focuses on UPS activation studies in cellular and organismal models and the effects of such activation on aging, longevity and disease prevention or reversal.
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Affiliation(s)
- Nikoletta Papaevgeniou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens, 11635, Greece
| | - Niki Chondrogianni
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens, 11635, Greece.
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28
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Dasgupta S, Fishman MA, Mahallati H, Castro LM, Tashima AK, Ferro ES, Fricker LD. Reduced Levels of Proteasome Products in a Mouse Striatal Cell Model of Huntington's Disease. PLoS One 2015; 10:e0145333. [PMID: 26691307 PMCID: PMC4686214 DOI: 10.1371/journal.pone.0145333] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 12/02/2015] [Indexed: 12/25/2022] Open
Abstract
Huntington's disease is the result of a long polyglutamine tract in the gene encoding huntingtin protein, which in turn causes a large number of cellular changes and ultimately results in neurodegeneration of striatal neurons. Although many theories have been proposed, the precise mechanism by which the polyglutamine expansion causes cellular changes is not certain. Some evidence supports the hypothesis that the long polyglutamine tract inhibits the proteasome, a multiprotein complex involved in protein degradation. However, other studies report normal proteasome function in cells expressing long polyglutamine tracts. The controversy may be due to the methods used to examine proteasome activity in each of the previous studies. In the present study, we measured proteasome function by examining levels of endogenous peptides that are products of proteasome cleavage. Peptide levels were compared among mouse striatal cell lines expressing either 7 glutamines (STHdhQ7/Q7) or 111 glutamines in the huntingtin protein, either heterozygous (STHdhQ7/Q111) or homozygous (STHdhQ111/Q111). Both of the cell lines expressing huntingtin with 111 glutamines showed a large reduction in nearly all of the peptides detected in the cells, relative to levels of these peptides in cells homozygous for 7 glutamines. Treatment of STHdhQ7/Q7 cells with proteasome inhibitors epoxomicin or bortezomib also caused a large reduction in most of these peptides, suggesting that they are products of proteasome-mediated cleavage of cellular proteins. Taken together, these results support the hypothesis that proteasome function is impaired by the expression of huntingtin protein containing long polyglutamine tracts.
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Affiliation(s)
- Sayani Dasgupta
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, New York, 10461, United States of America
| | - Michael A. Fishman
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, New York, 10461, United States of America
| | - Hana Mahallati
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, New York, 10461, United States of America
| | - Leandro M. Castro
- São Paulo State University (UNESP), Experimental Campus on the São Paulo Coast, São Vicente, 11330–900, SP, Brazil
| | - Alexandre K. Tashima
- Department of Biochemistry, Escola Paulista de Medicina, Federal University of Sao Paulo, Sao Paulo, SP, 04023–901, SP, Brazil
| | - Emer S. Ferro
- Department of Pharmacology, Biomedical Science Institute, University of São Paulo, São Paulo, 05508–000, SP, Brazil
| | - Lloyd D. Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, New York, 10461, United States of America
- Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, New York, 10461, United States of America
- * E-mail:
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29
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Chondrogianni N, Voutetakis K, Kapetanou M, Delitsikou V, Papaevgeniou N, Sakellari M, Lefaki M, Filippopoulou K, Gonos ES. Proteasome activation: An innovative promising approach for delaying aging and retarding age-related diseases. Ageing Res Rev 2015; 23:37-55. [PMID: 25540941 DOI: 10.1016/j.arr.2014.12.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 12/09/2014] [Accepted: 12/15/2014] [Indexed: 11/16/2022]
Abstract
Aging is a natural process accompanied by a progressive accumulation of damage in all constituent macromolecules (nucleic acids, lipids and proteins). Accumulation of damage in proteins leads to failure of proteostasis (or vice versa) due to increased levels of unfolded, misfolded or aggregated proteins and, in turn, to aging and/or age-related diseases. The major cellular proteolytic machineries, namely the proteasome and the lysosome, have been shown to dysfunction during aging and age-related diseases. Regarding the proteasome, it is well established that it can be activated either through genetic manipulation or through treatment with natural or chemical compounds that eventually result to extension of lifespan or deceleration of the progression of age-related diseases. This review article focuses on proteasome activation studies in several species and cellular models and their effects on aging and longevity. Moreover, it summarizes findings regarding proteasome activation in the major age-related diseases as well as in progeroid syndromes.
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Affiliation(s)
- Niki Chondrogianni
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece.
| | - Konstantinos Voutetakis
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece
| | - Marianna Kapetanou
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece
| | - Vasiliki Delitsikou
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece
| | - Nikoletta Papaevgeniou
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece
| | - Marianthi Sakellari
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece; Örebro University, Medical School, Örebro, Sweden
| | - Maria Lefaki
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece
| | - Konstantina Filippopoulou
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece
| | - Efstathios S Gonos
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, 48 Vas. Constantinou Ave., 116 35 Athens, Greece; Örebro University, Medical School, Örebro, Sweden.
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30
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Seidel K, Siswanto S, Fredrich M, Bouzrou M, Brunt ER, van Leeuwen FW, Kampinga HH, Korf HW, Rüb U, den Dunnen WFA. Polyglutamine aggregation in Huntington's disease and spinocerebellar ataxia type 3: similar mechanisms in aggregate formation. Neuropathol Appl Neurobiol 2015; 42:153-66. [DOI: 10.1111/nan.12253] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 05/14/2015] [Indexed: 01/19/2023]
Affiliation(s)
- K. Seidel
- Dr. Senckenbergisches Chronomedizinisches Institut; Goethe University; Frankfurt/Main Germany
| | - S. Siswanto
- Dr. Senckenbergisches Chronomedizinisches Institut; Goethe University; Frankfurt/Main Germany
| | - M. Fredrich
- Dr. Senckenbergisches Chronomedizinisches Institut; Goethe University; Frankfurt/Main Germany
| | - M. Bouzrou
- Dr. Senckenbergisches Chronomedizinisches Institut; Goethe University; Frankfurt/Main Germany
| | - E. R. Brunt
- Department of Neurology; University of Groningen; Groningen The Netherlands
| | - F. W. van Leeuwen
- Department of Neuroscience; Maastricht University; Maastricht The Netherlands
| | - H. H. Kampinga
- Cell Biology, Radiation and Stress Cell Biology; University of Groningen; Groningen The Netherlands
| | - H. -W. Korf
- Dr. Senckenbergisches Chronomedizinisches Institut; Goethe University; Frankfurt/Main Germany
| | - U. Rüb
- Dr. Senckenbergisches Chronomedizinisches Institut; Goethe University; Frankfurt/Main Germany
| | - W. F. A. den Dunnen
- Department of Pathology and Medical Biology; University Medical Center Groningen; University of Groningen; Groningen The Netherlands
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31
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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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32
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Wei L, Shen Y, Xu F, Hu F, Harrington JK, Targoff K, Min W. Imaging complex protein metabolism in live organisms by stimulated Raman scattering microscopy with isotope labeling. ACS Chem Biol 2015; 10:901-8. [PMID: 25560305 PMCID: PMC4610303 DOI: 10.1021/cb500787b] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 01/05/2015] [Indexed: 12/13/2022]
Abstract
Protein metabolism, consisting of both synthesis and degradation, is highly complex, playing an indispensable regulatory role throughout physiological and pathological processes. Over recent decades, extensive efforts, using approaches such as autoradiography, mass spectrometry, and fluorescence microscopy, have been devoted to the study of protein metabolism. However, noninvasive and global visualization of protein metabolism has proven to be highly challenging, especially in live systems. Recently, stimulated Raman scattering (SRS) microscopy coupled with metabolic labeling of deuterated amino acids (D-AAs) was demonstrated for use in imaging newly synthesized proteins in cultured cell lines. Herein, we significantly generalize this notion to develop a comprehensive labeling and imaging platform for live visualization of complex protein metabolism, including synthesis, degradation, and pulse-chase analysis of two temporally defined populations. First, the deuterium labeling efficiency was optimized, allowing time-lapse imaging of protein synthesis dynamics within individual live cells with high spatial-temporal resolution. Second, by tracking the methyl group (CH3) distribution attributed to pre-existing proteins, this platform also enables us to map protein degradation inside live cells. Third, using two subsets of structurally and spectroscopically distinct D-AAs, we achieved two-color pulse-chase imaging, as demonstrated by observing aggregate formation of mutant hungtingtin proteins. Finally, going beyond simple cell lines, we demonstrated the imaging ability of protein synthesis in brain tissues, zebrafish, and mice in vivo. Hence, the presented labeling and imaging platform would be a valuable tool to study complex protein metabolism with high sensitivity, resolution, and biocompatibility for a broad spectrum of systems ranging from cells to model animals and possibly to humans.
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Affiliation(s)
- Lu Wei
- Department of Chemistry, Kavli Institute for Brain Science, Columbia University, New York, New York 10027, United States
| | - Yihui Shen
- Department of Chemistry, Kavli Institute for Brain Science, Columbia University, New York, New York 10027, United States
| | - Fang Xu
- Department of Chemistry, Kavli Institute for Brain Science, Columbia University, New York, New York 10027, United States
| | - Fanghao Hu
- Department of Chemistry, Kavli Institute for Brain Science, Columbia University, New York, New York 10027, United States
| | - Jamie K. Harrington
- Department
of Pediatrics, Columbia University, New York, New York 10032, United States
| | - Kimara
L. Targoff
- Department
of Pediatrics, Columbia University, New York, New York 10032, United States
| | - Wei Min
- Department of Chemistry, Kavli Institute for Brain Science, Columbia University, New York, New York 10027, United States
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33
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Both ubiquitin ligases FBXW8 and PARK2 are sequestrated into insolubility by ATXN2 PolyQ expansions, but only FBXW8 expression is dysregulated. PLoS One 2015; 10:e0121089. [PMID: 25790475 PMCID: PMC4366354 DOI: 10.1371/journal.pone.0121089] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/27/2015] [Indexed: 12/13/2022] Open
Abstract
The involvement of the ubiquitin-proteasome system (UPS) in the course of various age-associated neurodegenerative diseases is well established. The single RING finger type E3 ubiquitin-protein ligase PARK2 is mutated in a Parkinson’s disease (PD) variant and was found to interact with ATXN2, a protein where polyglutamine expansions cause Spinocerebellar ataxia type 2 (SCA2) or increase the risk for Levodopa-responsive PD and for the motor neuron disease Amyotrophic lateral sclerosis (ALS). We previously reported evidence for a transcriptional induction of the multi-subunit RING finger Skp1/Cul/F-box (SCF) type E3 ubiquitin-protein ligase complex component FBXW8 in global microarray profiling of ATXN2-expansion mouse cerebellum and demonstrated its role for ATXN2 degradation in vitro. Now, we documented co-localization in vitro and co-immunoprecipitations both in vitro and in vivo, which indicate associations of FBXW8 with ATXN2 and PARK2. Both FBXW8 and PARK2 proteins are driven into insolubility by expanded ATXN2. Whereas the FBXW8 transcript upregulation by ATXN2- expansion was confirmed also in qPCR of skin fibroblasts and blood samples of SCA2 patients, a FBXW8 expression dysregulation was not observed in ATXN2-deficient mice, nor was a PARK2 transcript dysregulation observed in any samples. Jointly, all available data suggest that the degradation of wildtype and mutant ATXN2 is dependent on FBXW8, and that ATXN2 accumulation selectively modulates FBXW8 levels, while PARK2 might act indirectly through FBXW8. The effects of ATXN2-expansions on FBXW8 expression in peripheral tissues like blood may become useful for clinical diagnostics.
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34
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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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35
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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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36
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From pathways to targets: understanding the mechanisms behind polyglutamine disease. BIOMED RESEARCH INTERNATIONAL 2014; 2014:701758. [PMID: 25309920 PMCID: PMC4189765 DOI: 10.1155/2014/701758] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 09/03/2014] [Indexed: 12/27/2022]
Abstract
The history of polyglutamine diseases dates back approximately 20 years to the discovery of a polyglutamine repeat in the androgen receptor of SBMA followed by the identification of similar expansion mutations in Huntington's disease, SCA1, DRPLA, and the other spinocerebellar ataxias. This common molecular feature of polyglutamine diseases suggests shared mechanisms in disease pathology and neurodegeneration of disease specific brain regions. In this review, we discuss the main pathogenic pathways including proteolytic processing, nuclear shuttling and aggregation, mitochondrial dysfunction, and clearance of misfolded polyglutamine proteins and point out possible targets for treatment.
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37
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Jansen AHP, Reits EAJ, Hol EM. The ubiquitin proteasome system in glia and its role in neurodegenerative diseases. Front Mol Neurosci 2014; 7:73. [PMID: 25152710 PMCID: PMC4126450 DOI: 10.3389/fnmol.2014.00073] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/10/2014] [Indexed: 12/12/2022] Open
Abstract
The ubiquitin proteasome system (UPS) is crucial for intracellular protein homeostasis and for degradation of aberrant and damaged proteins. The accumulation of ubiquitinated proteins is a hallmark of many neurodegenerative diseases, including amyotrophic lateral sclerosis, Alzheimer’s, Parkinson’s, and Huntington’s disease, leading to the hypothesis that proteasomal impairment is contributing to these diseases. So far, most research related to the UPS in neurodegenerative diseases has been focused on neurons, while glial cells have been largely disregarded in this respect. However, glial cells are essential for proper neuronal function and adopt a reactive phenotype in neurodegenerative diseases, thereby contributing to an inflammatory response. This process is called reactive gliosis, which in turn affects UPS function in glial cells. In many neurodegenerative diseases, mostly neurons show accumulation and aggregation of ubiquitinated proteins, suggesting that glial cells may be better equipped to maintain proper protein homeostasis. During an inflammatory reaction, the immunoproteasome is induced in glia, which may contribute to a more efficient degradation of disease-related proteins. Here we review the role of the UPS in glial cells in various neurodegenerative diseases, and we discuss how studying glial cell function might provide essential information in unraveling mechanisms of neurodegenerative diseases.
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Affiliation(s)
- Anne H P Jansen
- Department of Cell Biology and Histology, Academic Medical Center Amsterdam, Netherlands
| | - Eric A J Reits
- Department of Cell Biology and Histology, Academic Medical Center Amsterdam, Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht Utrecht, Netherlands ; Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands ; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam Netherlands
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38
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How chemistry supports cell biology: the chemical toolbox at your service. Trends Cell Biol 2014; 24:751-60. [PMID: 25108565 DOI: 10.1016/j.tcb.2014.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/10/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023]
Abstract
Chemical biology is a young and rapidly developing scientific field. In this field, chemistry is inspired by biology to create various tools to monitor and modulate biochemical and cell biological processes. Chemical contributions such as small-molecule inhibitors and activity-based probes (ABPs) can provide new and unique insights into previously unexplored cellular processes. This review provides an overview of recent breakthroughs in chemical biology that are likely to have a significant impact on cell biology. We also discuss the application of several chemical tools in cell biology research.
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39
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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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