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Moldovean-Cioroianu NS. Reviewing the Structure-Function Paradigm in Polyglutamine Disorders: A Synergistic Perspective on Theoretical and Experimental Approaches. Int J Mol Sci 2024; 25:6789. [PMID: 38928495 PMCID: PMC11204371 DOI: 10.3390/ijms25126789] [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] [Received: 05/16/2024] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Polyglutamine (polyQ) disorders are a group of neurodegenerative diseases characterized by the excessive expansion of CAG (cytosine, adenine, guanine) repeats within host proteins. The quest to unravel the complex diseases mechanism has led researchers to adopt both theoretical and experimental methods, each offering unique insights into the underlying pathogenesis. This review emphasizes the significance of combining multiple approaches in the study of polyQ disorders, focusing on the structure-function correlations and the relevance of polyQ-related protein dynamics in neurodegeneration. By integrating computational/theoretical predictions with experimental observations, one can establish robust structure-function correlations, aiding in the identification of key molecular targets for therapeutic interventions. PolyQ proteins' dynamics, influenced by their length and interactions with other molecular partners, play a pivotal role in the polyQ-related pathogenic cascade. Moreover, conformational dynamics of polyQ proteins can trigger aggregation, leading to toxic assembles that hinder proper cellular homeostasis. Understanding these intricacies offers new avenues for therapeutic strategies by fine-tuning polyQ kinetics, in order to prevent and control disease progression. Last but not least, this review highlights the importance of integrating multidisciplinary efforts to advancing research in this field, bringing us closer to the ultimate goal of finding effective treatments against polyQ disorders.
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Affiliation(s)
- Nastasia Sanda Moldovean-Cioroianu
- Institute of Materials Science, Bioinspired Materials and Biosensor Technologies, Kiel University, Kaiserstraße 2, 24143 Kiel, Germany;
- Faculty of Physics, Babeș-Bolyai University, Kogălniceanu 1, RO-400084 Cluj-Napoca, Romania
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2
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Gkekas I, Gioran A, Boziki MK, Grigoriadis N, Chondrogianni N, Petrakis S. Oxidative Stress and Neurodegeneration: Interconnected Processes in PolyQ Diseases. Antioxidants (Basel) 2021; 10:antiox10091450. [PMID: 34573082 PMCID: PMC8471619 DOI: 10.3390/antiox10091450] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/03/2021] [Accepted: 09/08/2021] [Indexed: 12/16/2022] Open
Abstract
Neurodegenerative polyglutamine (polyQ) disorders are caused by trinucleotide repeat expansions within the coding region of disease-causing genes. PolyQ-expanded proteins undergo conformational changes leading to the formation of protein inclusions which are associated with selective neuronal degeneration. Several lines of evidence indicate that these mutant proteins are associated with oxidative stress, proteasome impairment and microglia activation. These events may correlate with the induction of inflammation in the nervous system and disease progression. Here, we review the effect of polyQ-induced oxidative stress in cellular and animal models of polyQ diseases. Furthermore, we discuss the interplay between oxidative stress, neurodegeneration and neuroinflammation using as an example the well-known neuroinflammatory disease, Multiple Sclerosis. Finally, we review some of the pharmaceutical interventions which may delay the onset and progression of polyQ disorders by targeting disease-associated mechanisms.
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Affiliation(s)
- Ioannis Gkekas
- Institute of Applied Biosciences/Centre for Research and Technology Hellas, 57001 Thessaloniki, Greece;
| | - Anna Gioran
- Institute of Chemical Biology, National Hellenic Research Foundation, 11635 Athens, Greece; (A.G.); (N.C.)
| | - Marina Kleopatra Boziki
- 2nd Neurological Department, AHEPA University General Hospital, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece; (M.K.B.); (N.G.)
| | - Nikolaos Grigoriadis
- 2nd Neurological Department, AHEPA University General Hospital, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece; (M.K.B.); (N.G.)
| | - Niki Chondrogianni
- Institute of Chemical Biology, National Hellenic Research Foundation, 11635 Athens, Greece; (A.G.); (N.C.)
| | - Spyros Petrakis
- Institute of Applied Biosciences/Centre for Research and Technology Hellas, 57001 Thessaloniki, Greece;
- Correspondence: ; Tel.: +30-2311257525
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3
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Hernandez R, Facelli JC. Structure analysis of the proteins associated with polyA repeat expansion disorders. J Biomol Struct Dyn 2021; 40:5556-5565. [PMID: 33459170 PMCID: PMC8286276 DOI: 10.1080/07391102.2021.1871957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Repeat regions are low-complexity regions in the human genome that largely code for intrinsic disorder in proteins. Expansions outside the normal thresholds in repeat regions are likely to be pathogenic, leading to the so-called repeat expansion diseases. There have been numerous studies on the most common group of repeat expansion diseases, which are the polyglutamine (polyQ) repeat expansion diseases, but there has been much less work done on the second-largest group of expansion repeats disorders, which involves the expansion of polyalanine (polyA) repeat tracts. In this article, we present a comprehensive study of the structural changes predicted using I-TASSER when comparing the wild type and enlarged structures of all known polyA expansion disorders. The results show that there is a reduction in α helices, an increase in extended strands in parallel and/or anti-parallel β-sheet conformation, an increase in random coils/loops and irregular elements, and a large increase in solvent-accessible surface area. When compared to the findings in polyQ expansions disorders we see similar trends, suggesting that the polyQ and polyA repeat expansion causes similar effects on the respective proteins, which lead to higher misfolding and aggregation propensities.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Rolando Hernandez
- Department of Biomedical Informatics, The University of Utah, Salt Lake City, UT, USA
| | - Julio C Facelli
- Department of Biomedical Informatics, The University of Utah, Salt Lake City, UT, USA.,Center for Clinical and Translational Science, The University of Utah, Salt Lake City, UT, USA
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4
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Association with proteasome determines pathogenic threshold of polyglutamine expansion diseases. Biochem Biophys Res Commun 2020; 536:95-99. [PMID: 33370719 DOI: 10.1016/j.bbrc.2020.12.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 12/18/2020] [Indexed: 11/21/2022]
Abstract
Expansion of glutamine residue track (polyQ) within soluble protein is responsible for eight autosomal-dominant genetic neurodegenerative disorders. These disorders affect cerebellum, striatum, basal ganglia and other brain regions. Each disease develops when polyQ expansion exceeds a pathogenic threshold (Qth). A pathogenic threshold is unique for each disease but the reasons for variability in Qth within this family of proteins are poorly understood. In the previous publication we proposed that polarity of the regions flanking polyQ track in each protein plays a key role in defining Qth value [1]. To explain the correlation between the polarity of the flanking sequences and Qth we performed quantitative analysis of interactions between polyQ-expanded proteins and proteasome. Based on structural and theoretical modeling, we predict that Qth value is determined by the energy of polar interaction of the flanking regions with the polyQ and proteasome. More polar flanking regions facilitate unfolding of α-helical polyQ conformation adopted inside the proteasome and as a result, increase Qth. Predictions of our model are consistent with Qth values observed in clinic for each of the eight polyQ-expansion disorders. Our results suggest that the agents that can destabilize polyQ α-helical structure may have a beneficial therapeutic effect for treatment of polyQ-expansion disorders.
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5
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Molecular determinants underlying functional innovations of TBP and their impact on transcription initiation. Nat Commun 2020; 11:2384. [PMID: 32404905 PMCID: PMC7221094 DOI: 10.1038/s41467-020-16182-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/13/2020] [Indexed: 02/07/2023] Open
Abstract
TATA-box binding protein (TBP) is required for every single transcription event in archaea and eukaryotes. It binds DNA and harbors two repeats with an internal structural symmetry that show sequence asymmetry. At various times in evolution, TBP has acquired multiple interaction partners and different organisms have evolved TBP paralogs with additional protein regions. Together, these observations raise questions of what molecular determinants (i.e. key residues) led to the ability of TBP to acquire new interactions, resulting in an increasingly complex transcriptional system in eukaryotes. We present a comprehensive study of the evolutionary history of TBP and its interaction partners across all domains of life, including viruses. Our analysis reveals the molecular determinants and suggests a unified and multi-stage evolutionary model for the functional innovations of TBP. These findings highlight how concerted chemical changes on a conserved structural scaffold allow for the emergence of complexity in a fundamental biological process. The TATA-box binding protein (TBP) is required for transcription initiation in archaea and eukaryotes. Here the authors delineate how TBP’s function has evolved new functional features through context-dependent interactions with various protein partners.
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Kevadiya BD, Ottemann BM, Thomas MB, Mukadam I, Nigam S, McMillan J, Gorantla S, Bronich TK, Edagwa B, Gendelman HE. Neurotheranostics as personalized medicines. Adv Drug Deliv Rev 2019; 148:252-289. [PMID: 30421721 PMCID: PMC6486471 DOI: 10.1016/j.addr.2018.10.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 12/16/2022]
Abstract
The discipline of neurotheranostics was forged to improve diagnostic and therapeutic clinical outcomes for neurological disorders. Research was facilitated, in largest measure, by the creation of pharmacologically effective multimodal pharmaceutical formulations. Deployment of neurotheranostic agents could revolutionize staging and improve nervous system disease therapeutic outcomes. However, obstacles in formulation design, drug loading and payload delivery still remain. These will certainly be aided by multidisciplinary basic research and clinical teams with pharmacology, nanotechnology, neuroscience and pharmaceutic expertise. When successful the end results will provide "optimal" therapeutic delivery platforms. The current report reviews an extensive body of knowledge of the natural history, epidemiology, pathogenesis and therapeutics of neurologic disease with an eye on how, when and under what circumstances neurotheranostics will soon be used as personalized medicines for a broad range of neurodegenerative, neuroinflammatory and neuroinfectious diseases.
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Affiliation(s)
- Bhavesh D Kevadiya
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Brendan M Ottemann
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Midhun Ben Thomas
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Insiya Mukadam
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Saumya Nigam
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - JoEllyn McMillan
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Santhi Gorantla
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Tatiana K Bronich
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Benson Edagwa
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Howard E Gendelman
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA; Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA.
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7
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Kuiper EFE, de Mattos EP, Jardim LB, Kampinga HH, Bergink S. Chaperones in Polyglutamine Aggregation: Beyond the Q-Stretch. Front Neurosci 2017; 11:145. [PMID: 28386214 PMCID: PMC5362620 DOI: 10.3389/fnins.2017.00145] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/08/2017] [Indexed: 01/12/2023] Open
Abstract
Expanded polyglutamine (polyQ) stretches in at least nine unrelated proteins lead to inherited neuronal dysfunction and degeneration. The expansion size in all diseases correlates with age at onset (AO) of disease and with polyQ protein aggregation, indicating that the expanded polyQ stretch is the main driving force for the disease onset. Interestingly, there is marked interpatient variability in expansion thresholds for a given disease. Between different polyQ diseases the repeat length vs. AO also indicates the existence of modulatory effects on aggregation of the upstream and downstream amino acid sequences flanking the Q expansion. This can be either due to intrinsic modulation of aggregation by the flanking regions, or due to differential interaction with other proteins, such as the components of the cellular protein quality control network. Indeed, several lines of evidence suggest that molecular chaperones have impact on the handling of different polyQ proteins. Here, we review factors differentially influencing polyQ aggregation: the Q-stretch itself, modulatory flanking sequences, interaction partners, cleavage of polyQ-containing proteins, and post-translational modifications, with a special focus on the role of molecular chaperones. By discussing typical examples of how these factors influence aggregation, we provide more insight on the variability of AO between different diseases as well as within the same polyQ disorder, on the molecular level.
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Affiliation(s)
- E F E Kuiper
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
| | - Eduardo P de Mattos
- Department of Cell Biology, University Medical Center Groningen, University of GroningenGroningen, Netherlands; Programa de Pós-Graduação em Genética e Biologia Molecular, Department of Genetics, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto AlegrePorto Alegre, Brazil
| | - Laura B Jardim
- Programa de Pós-Graduação em Genética e Biologia Molecular, Department of Genetics, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto AlegrePorto Alegre, Brazil; Departamento de Medicina Interna, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Harm H Kampinga
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
| | - Steven Bergink
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
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8
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Adegbuyiro A, Sedighi F, Pilkington AW, Groover S, Legleiter J. Proteins Containing Expanded Polyglutamine Tracts and Neurodegenerative Disease. Biochemistry 2017; 56:1199-1217. [PMID: 28170216 DOI: 10.1021/acs.biochem.6b00936] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Several hereditary neurological and neuromuscular diseases are caused by an abnormal expansion of trinucleotide repeats. To date, there have been 10 of these trinucleotide repeat disorders associated with an expansion of the codon CAG encoding glutamine (Q). For these polyglutamine (polyQ) diseases, there is a critical threshold length of the CAG repeat required for disease, and further expansion beyond this threshold is correlated with age of onset and symptom severity. PolyQ expansion in the translated proteins promotes their self-assembly into a variety of oligomeric and fibrillar aggregate species that accumulate into the hallmark proteinaceous inclusion bodies associated with each disease. Here, we review aggregation mechanisms of proteins with expanded polyQ-tracts, structural consequences of expanded polyQ ranging from monomers to fibrillar aggregates, the impact of protein context and post-translational modifications on aggregation, and a potential role for lipid membranes in aggregation. As the pathogenic mechanisms that underlie these disorders are often classified as either a gain of toxic function or loss of normal protein function, some toxic mechanisms associated with mutant polyQ tracts will also be discussed.
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Affiliation(s)
- Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Albert W Pilkington
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Sharon Groover
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States.,Blanchette Rockefeller Neurosciences Institute, Robert C. Byrd Health Sciences Center, P.O. Box 9304, West Virginia University , Morgantown, West Virginia 26506, United States.,NanoSAFE, P.O. Box 6223, West Virginia University , Morgantown, West Virginia 26506, United States
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9
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Wen J, Scoles DR, Facelli JC. Effects of the enlargement of polyglutamine segments on the structure and folding of ataxin-2 and ataxin-3 proteins. J Biomol Struct Dyn 2016; 35:504-519. [PMID: 26861241 DOI: 10.1080/07391102.2016.1152199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Spinocerebellar ataxia type 2 (SCA2) and type 3 (SCA3) are two common autosomal-dominant inherited ataxia syndromes, both of which are related to the unstable expansion of trinucleotide CAG repeats in the coding region of the related ATXN2 and ATXN3 genes, respectively. The poly-glutamine (poly-Q) tract encoded by the CAG repeats has long been recognized as an important factor in disease pathogenesis and progress. In this study, using the I-TASSER method for 3D structure prediction, we investigated the effect of poly-Q tract enlargement on the structure and folding of ataxin-2 and ataxin-3 proteins. Our results show good agreement with the known experimental structures of the Josephin and UIM domains providing credence to the simulation results presented here, which show that the enlargement of the poly-Q region not only affects the local structure of these regions but also affects the structures of functional domains as well as the whole protein. The changes observed in the predicted models of the UIM domains in ataxin-3 when the poly-Q track is enlarged provide new insights on possible pathogenic mechanisms.
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Affiliation(s)
- Jingran Wen
- a Department of Biomedical Informatics , University of Utah , Salt Lake City , UT , USA
| | - Daniel R Scoles
- b Department of Neurology , University of Utah , Salt Lake City , UT , USA
| | - Julio C Facelli
- a Department of Biomedical Informatics , University of Utah , Salt Lake City , UT , USA
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10
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Enhanced Store-Operated Calcium Entry Leads to Striatal Synaptic Loss in a Huntington's Disease Mouse Model. J Neurosci 2016; 36:125-41. [PMID: 26740655 DOI: 10.1523/jneurosci.1038-15.2016] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
UNLABELLED In Huntington's disease (HD), mutant Huntingtin (mHtt) protein causes striatal neuron dysfunction, synaptic loss, and eventual neurodegeneration. To understand the mechanisms responsible for synaptic loss in HD, we developed a corticostriatal coculture model that features age-dependent dendritic spine loss in striatal medium spiny neurons (MSNs) from YAC128 transgenic HD mice. Age-dependent spine loss was also observed in vivo in YAC128 MSNs. To understand the causes of spine loss in YAC128 MSNs, we performed a series of mechanistic studies. We previously discovered that mHtt protein binds to type 1 inositol (1,4,5)-trisphosphate receptor (InsP3R1) and increases its sensitivity to activation by InsP3. We now report that the resulting increase in steady-state InsP3R1 activity reduces endoplasmic reticulum (ER) Ca(2+) levels. Depletion of ER Ca(2+) leads to overactivation of the neuronal store-operated Ca(2+) entry (nSOC) pathway in YAC128 MSN spines. The synaptic nSOC pathway is controlled by the ER resident protein STIM2. We discovered that STIM2 expression is elevated in aged YAC128 striatal cultures and in YAC128 mouse striatum. Knock-down of InsP3R1 expression by antisense oligonucleotides or knock-down or knock-out of STIM2 resulted in normalization of nSOC and rescue of spine loss in YAC128 MSNs. The selective nSOC inhibitor EVP4593 was identified in our previous studies. We now demonstrate that EVP4593 reduces synaptic nSOC and rescues spine loss in YAC128 MSNs. Intraventricular delivery of EVP4593 in YAC128 mice rescued age-dependent striatal spine loss in vivo. Our results suggest EVP4593 and other inhibitors of the STIM2-dependent nSOC pathway as promising leads for HD therapeutic development. SIGNIFICANCE STATEMENT In Huntington's disease (HD) mutant Huntingtin (mHtt) causes early corticostriatal synaptic dysfunction and eventual neurodegeneration of medium spine neurons (MSNs) through poorly understood mechanisms. We report here that corticostriatal cocultures prepared from YAC128 HD mice feature age-dependent MSN spine loss, mirroring YAC128 MSN spine loss in vivo. This finding establishes a system for mechanistic studies of synaptic instability in HD. We use it to demonstrate that sensitization of type 1 inositol (1,4,5)-trisphosphate receptors by mHtt, which depletes endoplasmic reticulum calcium, contributes to synaptotoxic enhancement of STIM2-dependent store-operated calcium (SOC) entry. Treatment with EVP4593, a neuroprotective inhibitor of neuronal SOC channels, rescues YAC128 MSN spine loss both in vitro and in vivo. These results suggest that enhanced neuronal SOC causes synaptic loss in HD-afflicted MSNs.
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11
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Eftekharzadeh B, Hyman BT, Wegmann S. Structural studies on the mechanism of protein aggregation in age related neurodegenerative diseases. Mech Ageing Dev 2016; 156:1-13. [PMID: 27005270 DOI: 10.1016/j.mad.2016.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/12/2016] [Accepted: 03/03/2016] [Indexed: 01/09/2023]
Abstract
The progression of many neurodegenerative diseases is assumed to be caused by misfolding of specific characteristic diseases related proteins, resulting in aggregation and fibril formation of these proteins. Protein misfolding associated age related diseases, although different in disease manifestations, share striking similarities. In all cases, one disease protein aggregates and loses its function or additionally shows a toxic gain of function. However, the clear link between these individual amyloid-like protein aggregates and cellular toxicity is often still uncertain. The similar features of protein misfolding and aggregation in this group of proteins, all involved in age related neurodegenerative diseases, results in high interest in characterization of their structural properties. We review here recent findings on structural properties of some age related disease proteins, in the context of their biological importance in disease.
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Affiliation(s)
- Bahareh Eftekharzadeh
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA.
| | - Bradley T Hyman
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
| | - Susanne Wegmann
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
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12
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Zhemkov VA, Kulminskaya AA, Bezprozvanny IB, Kim M. The 2.2-Angstrom resolution crystal structure of the carboxy-terminal region of ataxin-3. FEBS Open Bio 2016; 6:168-78. [PMID: 27047745 PMCID: PMC4794786 DOI: 10.1002/2211-5463.12029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/23/2015] [Accepted: 12/27/2015] [Indexed: 01/15/2023] Open
Abstract
An expansion of polyglutamine (polyQ) sequence in ataxin‐3 protein causes spinocerebellar ataxia type 3, an inherited neurodegenerative disorder. The crystal structure of the polyQ‐containing carboxy‐terminal fragment of human ataxin‐3 was solved at 2.2‐Å resolution. The Atxn3 carboxy‐terminal fragment including 14 glutamine residues adopts both random coil and α‐helical conformations in the crystal structure. The polyQ sequence in α‐helical structure is stabilized by intrahelical hydrogen bonds mediated by glutamine side chains. The intrahelical hydrogen‐bond interactions between glutamine side chains along the axis of the polyQ α‐helix stabilize the secondary structure. Analysis of this structure furthers our understanding of the polyQ‐structural characteristics that likely underlie the pathogenesis of polyQ‐expansion disorders.
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Affiliation(s)
- Vladimir A Zhemkov
- Laboratory of Molecular Neurodegeneration St Petersburg State Polytechnical University Russia; Laboratory of Enzymology National Research Center «Kurchatov Institute»B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Russia
| | - Anna A Kulminskaya
- Laboratory of Molecular Neurodegeneration St Petersburg State Polytechnical University Russia; Laboratory of Enzymology National Research Center «Kurchatov Institute»B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration St Petersburg State Polytechnical University Russia; Department of Physiology University of Texas Southwestern Medical Center Dallas TX USA
| | - Meewhi Kim
- Laboratory of Molecular Neurodegeneration St Petersburg State Polytechnical University Russia; Department of Physiology University of Texas Southwestern Medical Center Dallas TX USA
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13
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Li X, Liu H, Fischhaber PL, Tang TS. Toward therapeutic targets for SCA3: Insight into the role of Machado-Joseph disease protein ataxin-3 in misfolded proteins clearance. Prog Neurobiol 2015; 132:34-58. [PMID: 26123252 DOI: 10.1016/j.pneurobio.2015.06.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/30/2015] [Accepted: 06/16/2015] [Indexed: 01/09/2023]
Abstract
Machado-Joseph disease (MJD, also known as spinocerebellar ataxia type 3, SCA3), an autosomal dominant neurological disorder, is caused by an abnormal expanded polyglutamine (polyQ) repeat in the ataxin-3 protein. The length of the expanded polyQ stretch correlates positively with the severity of the disease and inversely with the age at onset. To date, we cannot fully explain the mechanism underlying neurobiological abnormalities of this disease. Yet, accumulating reports have demonstrated the functions of ataxin-3 protein in the chaperone system, ubiquitin-proteasome system, and aggregation-autophagy, all of which suggest a role of ataxin-3 in the clearance of misfolded proteins. Notably, the SCA3 pathogenic form of ataxin-3 (ataxin-3(exp)) impairs the misfolded protein clearance via mechanisms that are either dependent or independent of its deubiquitinase (DUB) activity, resulting in the accumulation of misfolded proteins and the progressive loss of neurons in SCA3. Some drugs, which have been used as activators/inducers in the chaperone system, ubiquitin-proteasome system, and aggregation-autophagy, have been demonstrated to be efficacious in the relief of neurodegeneration diseases like Huntington's disease (HD), Parkinson's (PD), Alzheimer's (AD) as well as SCA3 in animal models and clinical trials, putting misfolded protein clearance on the list of potential therapeutic targets. Here, we undertake a comprehensive review of the progress in understanding the physiological functions of ataxin-3 in misfolded protein clearance and how the polyQ expansion impairs misfolded protein clearance. We then detail the preclinical studies targeting the elimination of misfolded proteins for SCA3 treatment. We close with future considerations for translating these pre-clinical results into therapies for SCA3 patients.
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Affiliation(s)
- Xiaoling Li
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongmei Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Paula L Fischhaber
- Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA 91330-8262, USA.
| | - Tie-Shan Tang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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