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Brady ST, Mesnard-Hoaglin NA, Mays S, Priego M, Dziechciowska J, Morris S, Kang M, Tsai MY, Purks JL, Klein A, Gaona A, Melloni A, Connors T, Hyman B, Song Y, Morfini GA. Toxic effects of mutant huntingtin in axons are mediated by its proline-rich domain. Brain 2024; 147:2098-2113. [PMID: 37633260 PMCID: PMC11146425 DOI: 10.1093/brain/awad280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/13/2023] [Accepted: 07/17/2023] [Indexed: 08/28/2023] Open
Abstract
Huntington's disease results from expansion of a polyglutamine tract (polyQ) in mutant huntingtin (mHTT) protein, but mechanisms underlying polyQ expansion-mediated toxic gain-of-mHTT function remain elusive. Here, deletion and antibody-based experiments revealed that a proline-rich domain (PRD) adjacent to the polyQ tract is necessary for mHTT to inhibit fast axonal transport and promote axonal pathology in cultured mammalian neurons. Further, polypeptides corresponding to subregions of the PRD sufficed to elicit the toxic effect on fast axonal transport, which was mediated by c-Jun N-terminal kinases (JNKs) and involved PRD binding to one or more SH3-domain containing proteins. Collectively, these data suggested a mechanism whereby polyQ tract expansion in mHTT promotes aberrant PRD exposure and interactions of this domain with SH3 domain-containing proteins including some involved in activation of JNKs. In support, biochemical and immunohistochemical experiments linked aberrant PRD exposure to increased JNK activation in striatal tissues of the zQ175 mouse model and from post-mortem Huntington's disease patients. Together, these findings support a critical role of PRD on mHTT toxicity, suggesting a novel framework for the potential development of therapies aimed to halt or reduce axonal pathology in Huntington's disease.
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Affiliation(s)
- Scott T Brady
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | | | - Sarah Mays
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Mercedes Priego
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Joanna Dziechciowska
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Sarah Morris
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Minsu Kang
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Ming Ying Tsai
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | | | - Alison Klein
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Angelica Gaona
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Alexandra Melloni
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Theresa Connors
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Bradley Hyman
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02129, USA
| | - Yuyu Song
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02129, USA
| | - Gerardo A Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
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2
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Zhang X, Chen C, Liu Y. Navigating the metabolic maze: anomalies in fatty acid and cholesterol processes in Alzheimer's astrocytes. Alzheimers Res Ther 2024; 16:63. [PMID: 38521950 PMCID: PMC10960454 DOI: 10.1186/s13195-024-01430-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, and its underlying mechanisms have been a subject of great interest. The mainstream theory of AD pathology suggests that the disease is primarily associated with tau protein and amyloid-beta (Aβ). However, an increasing body of research has revealed that abnormalities in lipid metabolism may be an important event throughout the pathophysiology of AD. Astrocytes, as important members of the lipid metabolism network in the brain, play a significant role in this event. The study of abnormal lipid metabolism in astrocytes provides a new perspective for understanding the pathogenesis of AD. This review focuses on the abnormal metabolism of fatty acids (FAs) and cholesterol in astrocytes in AD, and discusses it from three perspectives: lipid uptake, intracellular breakdown or synthesis metabolism, and efflux transport. We found that, despite the accumulation of their own fatty acids, astrocytes cannot efficiently uptake fatty acids from neurons, leading to fatty acid accumulation within neurons and resulting in lipotoxicity. In terms of cholesterol metabolism, astrocytes exhibit a decrease in endogenous synthesis due to the accumulation of exogenous cholesterol. Through a thorough investigation of these metabolic abnormalities, we can provide new insights for future therapeutic strategies by literature review to navigate this complex metabolic maze and bring hope to patients with Alzheimer's disease.
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Affiliation(s)
- Xiaoyu Zhang
- Department of Neurosurgery, Institute of Brain Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Chuanying Chen
- Department of Neurosurgery, Institute of Brain Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
- School of Traditional Chinese Medicine, Southern Medical University, 1838 North Guangzhou Avenue, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Yi Liu
- Department of Neurosurgery, Institute of Brain Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China.
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3
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Podvin S, Rosenthal SB, Poon W, Wei E, Fisch KM, Hook V. Mutant Huntingtin Protein Interaction Map Implicates Dysregulation of Multiple Cellular Pathways in Neurodegeneration of Huntington's Disease. J Huntingtons Dis 2022; 11:243-267. [PMID: 35871359 PMCID: PMC9484122 DOI: 10.3233/jhd-220538] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Huntington's disease (HD) is a genetic neurodegenerative disease caused by trinucleotide repeat (CAG) expansions in the human HTT gene encoding the huntingtin protein (Htt) with an expanded polyglutamine tract. OBJECTIVE HD models from yeast to transgenic mice have investigated proteins interacting with mutant Htt that may initiate molecular pathways of cell death. There is a paucity of datasets of published Htt protein interactions that include the criteria of 1) defining fragments or full-length Htt forms, 2) indicating the number of poly-glutamines of the mutant and wild-type Htt forms, and 3) evaluating native Htt interaction complexes. This research evaluated such interactor data to gain understanding of Htt dysregulation of cellular pathways. METHODS Htt interacting proteins were compiled from the literature that meet our criteria and were subjected to network analysis via clustering, gene ontology, and KEGG pathways using rigorous statistical methods. RESULTS The compiled data of Htt interactors found that both mutant and wild-type Htt interact with more than 2,971 proteins. Application of a community detection algorithm to all known Htt interactors identified significant signal transduction, membrane trafficking, chromatin, and mitochondrial clusters, among others. Binomial analyses of a subset of reported protein interactor information determined that chromatin organization, signal transduction and endocytosis were diminished, while mitochondria, translation and membrane trafficking had enriched overall edge effects. CONCLUSION The data support the hypothesis that mutant Htt disrupts multiple cellular processes causing toxicity. This dataset is an open resource to aid researchers in formulating hypotheses of HD mechanisms of pathogenesis.
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Affiliation(s)
- Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Sara Brin Rosenthal
- Center for Computational Biology & Bioinformatics, University of California, San Diego, La Jolla, CA, USA
| | - William Poon
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Enlin Wei
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Kathleen M Fisch
- Center for Computational Biology & Bioinformatics, University of California, San Diego, La Jolla, CA, USA.,Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA.,Department of Neuroscience and Dept of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA, USA
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4
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Kim C, Yousefian-Jazi A, Choi SH, Chang I, Lee J, Ryu H. Non-Cell Autonomous and Epigenetic Mechanisms of Huntington's Disease. Int J Mol Sci 2021; 22:12499. [PMID: 34830381 PMCID: PMC8617801 DOI: 10.3390/ijms222212499] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/10/2021] [Accepted: 11/15/2021] [Indexed: 02/06/2023] Open
Abstract
Huntington's disease (HD) is a rare neurodegenerative disorder caused by an expansion of CAG trinucleotide repeat located in the exon 1 of Huntingtin (HTT) gene in human chromosome 4. The HTT protein is ubiquitously expressed in the brain. Specifically, mutant HTT (mHTT) protein-mediated toxicity leads to a dramatic degeneration of the striatum among many regions of the brain. HD symptoms exhibit a major involuntary movement followed by cognitive and psychiatric dysfunctions. In this review, we address the conventional role of wild type HTT (wtHTT) and how mHTT protein disrupts the function of medium spiny neurons (MSNs). We also discuss how mHTT modulates epigenetic modifications and transcriptional pathways in MSNs. In addition, we define how non-cell autonomous pathways lead to damage and death of MSNs under HD pathological conditions. Lastly, we overview therapeutic approaches for HD. Together, understanding of precise neuropathological mechanisms of HD may improve therapeutic approaches to treat the onset and progression of HD.
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Affiliation(s)
- Chaebin Kim
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea; (C.K.); (A.Y.-J.); (S.-H.C.)
| | - Ali Yousefian-Jazi
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea; (C.K.); (A.Y.-J.); (S.-H.C.)
| | - Seung-Hye Choi
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea; (C.K.); (A.Y.-J.); (S.-H.C.)
| | - Inyoung Chang
- Department of Biology, Boston University, Boston, MA 02215, USA;
| | - Junghee Lee
- Boston University Alzheimer’s Disease Research Center, Boston University, Boston, MA 02118, USA
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA
- VA Boston Healthcare System, Boston, MA 02130, USA
| | - Hoon Ryu
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea; (C.K.); (A.Y.-J.); (S.-H.C.)
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5
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Chang YC, Kim JY. Therapeutic implications of circadian clocks in neurodegenerative diseases. J Neurosci Res 2019; 98:1095-1113. [PMID: 31833091 DOI: 10.1002/jnr.24572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 11/22/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022]
Abstract
Circadian clocks, endogenous oscillators generating daily biological rhythms, have important roles in the nervous system to control diverse cellular processes-not only in the suprachiasmatic nucleus (SCN), where the master clocks reside to synchronize all circadian clocks in the body but also in other non-SCN areas. Accumulating evidence has shown relationships between circadian abnormalities (e.g., sleep disturbances and abnormal rest-activity rhythms) and disease progressions in various neurodegenerative diseases, including Alzheimer's (AD) and Parkinson's (PD) disease. Although circadian abnormalities were frequently considered as consequences of disease onsets, recent studies suggest altered circadian clocks as risk factors to develop neurodegenerative diseases via altered production or clearance rates of toxic metabolites like amyloid β. In this review, we will summarize circadian clock-related pathologies in the most common neurodegenerative diseases in the central nervous system, AD and PD. Then, we will introduce the current clinical trials to rescue circadian abnormalities in AD and PD patients. Finally, a discussion about how to improve targeting circadian clocks to increase treatment efficiencies and specificities will be followed. This discussion will provide insight into circadian clocks as potential therapeutic targets to attenuate onsets and progressions of neurodegenerative diseases.
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Affiliation(s)
- Yu Chen Chang
- Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Jin Young Kim
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong
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6
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van Well EM, Bader V, Patra M, Sánchez-Vicente A, Meschede J, Furthmann N, Schnack C, Blusch A, Longworth J, Petrasch-Parwez E, Mori K, Arzberger T, Trümbach D, Angersbach L, Showkat C, Sehr DA, Berlemann LA, Goldmann P, Clement AM, Behl C, Woerner AC, Saft C, Wurst W, Haass C, Ellrichmann G, Gold R, Dittmar G, Hipp MS, Hartl FU, Tatzelt J, Winklhofer KF. A protein quality control pathway regulated by linear ubiquitination. EMBO J 2019; 38:e100730. [PMID: 30886048 PMCID: PMC6484417 DOI: 10.15252/embj.2018100730] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 12/22/2022] Open
Abstract
Neurodegenerative diseases are characterized by the accumulation of misfolded proteins in the brain. Insights into protein quality control mechanisms to prevent neuronal dysfunction and cell death are crucial in developing causal therapies. Here, we report that various disease-associated protein aggregates are modified by the linear ubiquitin chain assembly complex (LUBAC). HOIP, the catalytic component of LUBAC, is recruited to misfolded Huntingtin in a p97/VCP-dependent manner, resulting in the assembly of linear polyubiquitin. As a consequence, the interactive surface of misfolded Huntingtin species is shielded from unwanted interactions, for example with the low complexity sequence domain-containing transcription factor Sp1, and proteasomal degradation of misfolded Huntingtin is facilitated. Notably, all three core LUBAC components are transcriptionally regulated by Sp1, linking defective LUBAC expression to Huntington's disease. In support of a protective activity of linear ubiquitination, silencing of OTULIN, a deubiquitinase with unique specificity for linear polyubiquitin, decreases proteotoxicity, whereas silencing of HOIP has the opposite effect. These findings identify linear ubiquitination as a protein quality control mechanism and hence a novel target for disease-modifying strategies in proteinopathies.
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Affiliation(s)
- Eva M van Well
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Verian Bader
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Maria Patra
- Neurobiochemistry, Adolf Butenandt Institute, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Ana Sánchez-Vicente
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Jens Meschede
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Nikolas Furthmann
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Cathrin Schnack
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Alina Blusch
- Department of Neurology, St Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Joseph Longworth
- Proteome and Genome Research Unit, Department of Oncology, Luxembourg Institute of Health, Strassen, Luxembourg
| | | | - Kohji Mori
- Biomedical Center (BMC), Ludwig-Maximilians-University Munich, Munich, Germany
| | - Thomas Arzberger
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University Munich, Munich, Germany
- Centre for Neuropathology and Prion Research, Ludwig-Maximilians-University Munich, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Dietrich Trümbach
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Lena Angersbach
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Cathrin Showkat
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Dominik A Sehr
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Lena A Berlemann
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Petra Goldmann
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Albrecht M Clement
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Christian Behl
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Andreas C Woerner
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Carsten Saft
- Department of Neurology, St Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Wolfgang Wurst
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Developmental Genetics, Technical University Munich, Neuherberg, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Christian Haass
- Biomedical Center (BMC), Ludwig-Maximilians-University Munich, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Gisa Ellrichmann
- Department of Neurology, St Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Ralf Gold
- Department of Neurology, St Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Gunnar Dittmar
- Proteome and Genome Research Unit, Department of Oncology, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Mark S Hipp
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Jörg Tatzelt
- Neurobiochemistry, Adolf Butenandt Institute, Ludwig-Maximilians-University Munich, Munich, Germany
- Department of Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
- Cluster of Excellence RESOLV, Bochum, Germany
| | - Konstanze F Winklhofer
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
- Neurobiochemistry, Adolf Butenandt Institute, Ludwig-Maximilians-University Munich, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- Cluster of Excellence RESOLV, Bochum, Germany
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7
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Galan-Rodriguez B, Martin E, Brouillet E, Déglon N, Betuing S, Caboche J. Coupling of D2R Short but not D2R Long receptor isoform to the Rho/ROCK signaling pathway renders striatal neurons vulnerable to mutant huntingtin. Eur J Neurosci 2016; 45:198-206. [PMID: 27717053 DOI: 10.1111/ejn.13415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 09/09/2016] [Accepted: 09/21/2016] [Indexed: 01/27/2023]
Abstract
Huntington's disease, an inherited neurodegenerative disorder, results from abnormal polyglutamine extension in the N-terminal region of the huntingtin protein. This mutation causes preferential degeneration of striatal projection neurons. We previously demonstrated, in vitro, that dopaminergic D2 receptor stimulation acted in synergy with expanded huntingtin to increase aggregates formation and striatal death through activation of the Rho/ROCK signaling pathway. In vivo, in a lentiviral-mediated model of expanded huntingtin expression in the rat striatum, we found that the D2 antagonist haloperidol protects striatal neurons against expanded huntingtin-mediated toxicity. Two variant transcripts are generated by alternative splicing of the of D2 receptor gene, the D2R-Long and the D2R-Short, which are thought to play different functional roles. We show herein that overexpression of D2R-Short, but not D2R-Long in cell lines is associated with activation of the RhoA/ROCK signaling pathway. In striatal neurons in culture, the selective D2 agonist Quinpirole triggers phosphorylation of cofilin, a downstream effector of ROCK, which is abrogated by siRNAs that knockdown both D2R-Long and D2R-Short, but not by siRNAs targeting D2R-Long alone. Aggregate formation and neuronal death induced by expanded huntingtin, were potentiated by Quinpirole. This D2 agonist-mediated effect was selectively inhibited by the siRNA targeting both D2R-Long and D2R-Short but not D2R-Long alone. Our data provide evidence for a specific coupling of D2R-Short to the RhoA/ROCK/cofilin pathway, and its involvement in striatal vulnerability to expanded huntingtin. A new route for targeting Rho-ROCK signaling in Huntington's disease is unraveled with our findings.
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Affiliation(s)
- Beatriz Galan-Rodriguez
- UMRS-INSERM1130, Neurosciences Paris Seine, Paris, France.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain
| | - Elodie Martin
- INSERM UMRS_1127/UPMC/CNRS UMR7225, Institut du Cerveau et de la Moelle, Hôpital Pitié-Salpêtrière, Paris, France
| | - Emmanuel Brouillet
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), Fontenay-aux-Roses, France.,Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, Fontenay-aux-Roses, France
| | - Nicole Déglon
- Department of Clinical Neurosciences (DNC), Laboratory of Cellular and Molecular Neurotherapies (LNCM), Lausanne University Medical School (CHUV), Lausanne, Switzerland.,Neuroscience Research Center (CRN), Laboratory of Cellular and Molecular Neurotherapies (LNCM), Lausanne University Medical School (CHUV), Lausanne, Switzerland
| | - Sandrine Betuing
- UMRS-INSERM1130, Neurosciences Paris Seine, Paris, France.,UMR CNRS-8246, Paris, France.,Sorbonne Université, UM119, Université Pierre and Marie Curie-Paris 6, 9 quai Saint Bernard, 75005, Paris, France
| | - Jocelyne Caboche
- UMRS-INSERM1130, Neurosciences Paris Seine, Paris, France.,UMR CNRS-8246, Paris, France.,Sorbonne Université, UM119, Université Pierre and Marie Curie-Paris 6, 9 quai Saint Bernard, 75005, Paris, France
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8
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Wityak J, McGee KF, Conlon MP, Song RH, Duffy BC, Clayton B, Lynch M, Wang G, Freeman E, Haber J, Kitchen DB, Manning DD, Ismail J, Khmelnitsky Y, Michels P, Webster J, Irigoyen M, Luche M, Hultman M, Bai M, Kuok ID, Newell R, Lamers M, Leonard P, Yates D, Matthews K, Ongeri L, Clifton S, Mead T, Deupree S, Wheelan P, Lyons K, Wilson C, Kiselyov A, Toledo-Sherman L, Beconi M, Muñoz-Sanjuan I, Bard J, Dominguez C. Lead optimization toward proof-of-concept tools for Huntington's disease within a 4-(1H-pyrazol-4-yl)pyrimidine class of pan-JNK inhibitors. J Med Chem 2015; 58:2967-87. [PMID: 25760409 DOI: 10.1021/jm5013598] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Through medicinal chemistry lead optimization studies focused on calculated properties and guided by X-ray crystallography and computational modeling, potent pan-JNK inhibitors were identified that showed submicromolar activity in a cellular assay. Using in vitro ADME profiling data, 9t was identified as possessing favorable permeability and a low potential for efflux, but it was rapidly cleared in liver microsomal incubations. In a mouse pharmacokinetics study, compound 9t was brain-penetrant after oral dosing, but exposure was limited by high plasma clearance. Brain exposure at a level expected to support modulation of a pharmacodynamic marker in mouse was achieved when the compound was coadministered with the pan-cytochrome P450 inhibitor 1-aminobenzotriazole.
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Affiliation(s)
- John Wityak
- †CHDI Foundation, Inc., 6080 Center Drive, Suite 100, Los Angeles, California 90045, United States
| | - Kevin F McGee
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Michael P Conlon
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Ren Hua Song
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Bryan C Duffy
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Brent Clayton
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Michael Lynch
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Gwen Wang
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Emily Freeman
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - James Haber
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Douglas B Kitchen
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - David D Manning
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Jiffry Ismail
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Yuri Khmelnitsky
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Peter Michels
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Jeff Webster
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Macarena Irigoyen
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Michele Luche
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Monica Hultman
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Mei Bai
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - IokTeng D Kuok
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Ryan Newell
- ‡Albany Molecular Research Inc. (AMRI), 26 Corporate Circle, Albany, New York 12212-5098, United States
| | - Marieke Lamers
- §BioFocus Discovery Services, Charles River Laboratories, Chesterford Research Park, Little Chesterford, CB10 1XL, United Kingdom
| | - Philip Leonard
- §BioFocus Discovery Services, Charles River Laboratories, Chesterford Research Park, Little Chesterford, CB10 1XL, United Kingdom
| | - Dawn Yates
- §BioFocus Discovery Services, Charles River Laboratories, Chesterford Research Park, Little Chesterford, CB10 1XL, United Kingdom
| | - Kim Matthews
- §BioFocus Discovery Services, Charles River Laboratories, Chesterford Research Park, Little Chesterford, CB10 1XL, United Kingdom
| | - Lynette Ongeri
- §BioFocus Discovery Services, Charles River Laboratories, Chesterford Research Park, Little Chesterford, CB10 1XL, United Kingdom
| | - Steve Clifton
- §BioFocus Discovery Services, Charles River Laboratories, Chesterford Research Park, Little Chesterford, CB10 1XL, United Kingdom
| | - Tania Mead
- §BioFocus Discovery Services, Charles River Laboratories, Chesterford Research Park, Little Chesterford, CB10 1XL, United Kingdom
| | - Susan Deupree
- ∥Tandem Laboratories, 2202 Ellis Road, Durham, North Carolina 27703, United States
| | - Pat Wheelan
- ∥Tandem Laboratories, 2202 Ellis Road, Durham, North Carolina 27703, United States
| | - Kathy Lyons
- ⊥Pharmacokinetics Consultant to CHDI, P.O. Box 64, Holland, New York 14080, United States
| | - Claire Wilson
- #Evotec, 114 Milton Park, Abingdon, OX14 4SA, United Kingdom
| | - Alex Kiselyov
- †CHDI Foundation, Inc., 6080 Center Drive, Suite 100, Los Angeles, California 90045, United States
| | - Leticia Toledo-Sherman
- †CHDI Foundation, Inc., 6080 Center Drive, Suite 100, Los Angeles, California 90045, United States
| | - Maria Beconi
- †CHDI Foundation, Inc., 6080 Center Drive, Suite 100, Los Angeles, California 90045, United States
| | - Ignacio Muñoz-Sanjuan
- †CHDI Foundation, Inc., 6080 Center Drive, Suite 100, Los Angeles, California 90045, United States
| | - Jonathan Bard
- †CHDI Foundation, Inc., 6080 Center Drive, Suite 100, Los Angeles, California 90045, United States
| | - Celia Dominguez
- †CHDI Foundation, Inc., 6080 Center Drive, Suite 100, Los Angeles, California 90045, United States
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9
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Truant R, Raymond LA, Xia J, Pinchev D, Burtnik A, Atwal RS. Canadian Association of Neurosciences Review: Polyglutamine Expansion Neurodegenerative Diseases. Can J Neurol Sci 2014; 33:278-91. [PMID: 17001815 DOI: 10.1017/s031716710000514x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
ABSTRACT:Since the early 1990s, DNA triplet repeat expansions have been found to be the cause in an ever increasing number of genetic neurologic diseases. A subset of this large family of genetic diseases has the expansion of a CAG DNA triplet in the open reading frame of a coding exon. The result of this DNA expansion is the expression of expanded glutamine amino acid repeat tracts in the affected proteins, leading to the term, Polyglutamine Diseases, which is applied to this sub-family of diseases. To date, nine distinct genes are known to be linked to polyglutamine diseases, including Huntington's disease, Machado-Joseph Disease and spinobulbar muscular atrophy or Kennedy's disease. Most of the polyglutamine diseases are characterized clinically as spinocerebellar ataxias. Here we discuss recent successes and advancements in polyglutamine disease research, comparing these different diseases with a common genetic flaw at the level of molecular biology and early drug design for a family of diseases where many new research tools for these genetic disorders have been developed. Polyglutamine disease research has successfully used interdisciplinary collaborative efforts, informative multiple mouse genetic models and advanced tools of pharmaceutical industry research to potentially serve as the prototype model of therapeutic research and development for rare neurodegenerative diseases.
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Affiliation(s)
- Ray Truant
- Department of Biochemistry and Biomedical Sciences McMaster University, Hamilton, ON, Canada
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10
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Ethyl pyruvate ameliorates 3-nitropropionic acid-induced striatal toxicity through anti-neuronal cell death and anti-inflammatory mechanisms. Brain Behav Immun 2014; 38:151-65. [PMID: 24576481 DOI: 10.1016/j.bbi.2014.01.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/15/2014] [Accepted: 01/26/2014] [Indexed: 01/17/2023] Open
Abstract
The potential neuroprotective value of ethyl pyruvate (EP) for the treatment of the striatal toxicity is largely unknown. We investigated whether EP promotes the survival of striatal neurons in a 3-nitropropionic acid (3-NP)-induced mouse model of Huntington's disease (HD). EP (5, 10, 20, and 40mg/kg/day, i.p.) was daily injected from 30min before 3-NP intoxication (pretreatment) and from onset/progression/peak point of neurological impairment by 3-NP intoxication. EP produced a neuroprotective effect in dose- and time-dependant manners. EP pretreatment of 40mg/kg/day produced the best neuroprotective effect among other conditions. Pretreatment of EP significantly attenuated neurological impairment and lethality and prevented formation of lesion area and neuronal loss in the striatum after 3-NP intoxication. This neuroprotection afforded by EP was associated with the suppression of succinate dehydrogenase activity, apoptosis, and microglial activation. The suppressive effect of EP corresponded to the down-regulation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) signal pathways, and mRNA expression of inflammatory mediators including tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6, inducible nitric oxide synthase, and cyclooxygenase-2 in the striatum after 3-NP intoxication. Interestingly, the intrathecal introduction of inhibitors MAPKs and NF-κB into control mice decreased the lethality after 3-NP intoxication. Our findings indicate that EP may effectively alleviate 3-NP-induced striatal toxicity by inhibition of the MAPKs and NF-κB pathways in the striatum, and that EP has a wide therapeutic window, suggesting that EP may have therapeutic value in the treatment of aspects of HD's disease related to inflammation.
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Park JE, Lee ST, Im WS, Kim M. Growth Hormone Deteriorates the Functional Outcome in an Experimental Model of Huntington's Disease Induced by 3-Nitropionic Acid. J Mov Disord 2013; 6:28-33. [PMID: 24868423 PMCID: PMC4027642 DOI: 10.14802/jmd.13007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 06/14/2013] [Accepted: 08/20/2013] [Indexed: 12/18/2022] Open
Abstract
Background and Purpose: Growth hormone (GH) has been frequently used to control the aging process in healthy individuals, probably due to its slowing effect on senescence-associated degeneration. Mitochondrial dysfunction is related to the aging process, and one of the chemical models of Huntington’s disease is that it can be induced by mitochondrial toxin. To investigate the potential application of GH to modify the progression of Huntington’s disease (HD), we examined whether GH can protect the functional deterioration by striatal damage induced by 3-nitropropionic acid (3NP). Methods: 3NP (63 mg/kg/day) was delivered to Lewis rats by osmotic pumps for five consecutive days, and the rats received intraperitoneal administration of GH or vehicle (saline) throughout the experiment. Neurological deficits and body weight were monitored. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test was performed to further determine the mitochondrial activity in cultured N18TG2 neuroblastoma cells in vitro. Results: 3NP-treated rats showed progressive neurologic deficits with striatal damage. Application of GH accelerated behavioral deterioration, particularly between day 3 and day 5, resulting in reduced survival outcome. The body weights of rats given 3NP were decreased, but GH did not affect such decrease compared to the non-treated control group. The effect of GH on cultured neuronal cells was a decrease in the MTT absorbance, suggesting a lower number of cells in a dose dependent pattern. Conclusions: Those results suggest that application of GH to a 3NP-induced experimental model of HD deteriorates the progress of functional deficits, possibly disturbing mitochondrial activities.
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Affiliation(s)
- Jung-Eun Park
- Department of Neurology, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea ; Program in Neuroscience, Seoul National University, Seoul, Korea
| | - Soon-Tae Lee
- Department of Neurology, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea ; Program in Neuroscience, Seoul National University, Seoul, Korea
| | - Woo-Seok Im
- Department of Neurology, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Manho Kim
- Department of Neurology, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea ; Program in Neuroscience, Seoul National University, Seoul, Korea
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12
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Korean Red Ginseng Extract Attenuates 3-Nitropropionic Acid-Induced Huntington's-Like Symptoms. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:237207. [PMID: 23431333 PMCID: PMC3568869 DOI: 10.1155/2013/237207] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Revised: 11/29/2012] [Accepted: 12/02/2012] [Indexed: 11/17/2022]
Abstract
Korean red ginseng (KRG) possesses neuroprotective activity. However, the potential neuroprotective value of KRG for the striatal toxicity is largely unknown. We investigated whether KRG extract (KRGE) could have a neuroprotective effect in a 3-nitropropionic acid- (3-NP) induced (i.p.) Huntington's disease (HD) model. KRGE (50, 100, and 250 mg/kg/day, p.o.) was administrated 10 days before 3-NP injection (pre-administration), from the same time with 3-NP injection (co-administration), or from the peak point of neurological impairment by 3-NP injection (post-administration). Pre-administration of KRGE produced the greatest neuroprotective effect in this model. Pre-administration of KRGE significantly decreased 3-NP-induced neurological impairment, lethality, lesion area, and neuronal loss in the 3-NP-injected striatum. KRGE attenuated microglial activation and phosphorylation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) signal pathway. KRGE also reduced the level of mRNA expression of tumor necrosis factor-alpha, interleukin- (IL-) 1β, IL-6, inducible nitric oxide synthase, and OX-42. Interestingly, the intrathecal administration of SB203580 (a p38 inhibitor) or PD98059 (an inhibitor of MAPK Kinase, MEK) increased the survival rate in the 3-NP-induced HD model. Pre-administration of KRGE may effectively inhibit 3-NP-induced striatal toxicity via the inhibition of the phosphorylation of MAPKs and NF-κB pathways, indicating its therapeutic potential for suppressing Huntington's-like symptoms.
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13
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Prion propagation and toxicity occur in vitro with two-phase kinetics specific to strain and neuronal type. J Virol 2012; 87:2535-48. [PMID: 23255799 DOI: 10.1128/jvi.03082-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Prion diseases, or transmissible spongiform encephalopathies (TSEs), are fatal neurodegenerative disorders that occur in humans and animals. The neuropathological hallmarks of TSEs are spongiosis, glial proliferation, and neuronal loss. The only known specific molecular marker of TSEs is the abnormal isoform (PrP(Sc)) of the host-encoded prion protein (PrP(C)), which accumulates in the brain of infected subjects and forms infectious prion particles. Although this transmissible agent lacks a specific nucleic acid component, several prion strains have been isolated. Prion strains are characterized by differences in disease outcome, PrP(Sc) distribution patterns, and brain lesion profiles at the terminal stage of the disease. The molecular factors and cellular mechanisms involved in strain-specific neuronal tropism and toxicity remain largely unknown. Currently, no cellular model exists to facilitate in vitro studies of these processes. A few cultured cell lines that maintain persistent scrapie infections have been developed, but only two of them have shown the cytotoxic effects associated with prion propagation. In this study, we have developed primary neuronal cultures to assess in vitro neuronal tropism and toxicity of different prion strains (scrapie strains 139A, ME7, and 22L). We have tested primary neuronal cultures enriched in cerebellar granular, striatal, or cortical neurons. Our results showed that (i) a strain-specific neuronal tropism operated in vitro; (ii) the cytotoxic effect varied among strains and neuronal cell types; (iii) prion propagation and toxicity occurred in two kinetic phases, a replicative phase followed by a toxic phase; and (iv) neurotoxicity peaked when abnormal PrP accumulation reached a plateau.
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14
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Roze E, Cahill E, Martin E, Bonnet C, Vanhoutte P, Betuing S, Caboche J. Huntington's Disease and Striatal Signaling. Front Neuroanat 2011; 5:55. [PMID: 22007160 PMCID: PMC3188786 DOI: 10.3389/fnana.2011.00055] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 08/04/2011] [Indexed: 12/05/2022] Open
Abstract
Huntington’s Disease (HD) is the most frequent neurodegenerative disease caused by an expansion of polyglutamines (CAG). The main clinical manifestations of HD are chorea, cognitive impairment, and psychiatric disorders. The transmission of HD is autosomal dominant with a complete penetrance. HD has a single genetic cause, a well-defined neuropathology, and informative pre-manifest genetic testing of the disease is available. Striatal atrophy begins as early as 15 years before disease onset and continues throughout the period of manifest illness. Therefore, patients could theoretically benefit from therapy at early stages of the disease. One important characteristic of HD is the striatal vulnerability to neurodegeneration, despite similar expression of the protein in other brain areas. Aggregation of the mutated Huntingtin (HTT), impaired axonal transport, excitotoxicity, transcriptional dysregulation as well as mitochondrial dysfunction, and energy deficits, are all part of the cellular events that underlie neuronal dysfunction and striatal death. Among these non-exclusive mechanisms, an alteration of striatal signaling is thought to orchestrate the downstream events involved in the cascade of striatal dysfunction.
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Affiliation(s)
- Emmanuel Roze
- UMRS 952, INSERM, UMR 7224, CNRS Université Pierre et Marie Curie - Paris-6 Paris, France
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15
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Nagashima S, Fukuda T, Kubota Y, Sugiura A, Nakao M, Inatome R, Yanagi S. CRMP5-associated GTPase (CRAG) protein protects neuronal cells against cytotoxicity of expanded polyglutamine protein partially via c-Fos-dependent activator protein-1 activation. J Biol Chem 2011; 286:33879-89. [PMID: 21832068 DOI: 10.1074/jbc.m111.234997] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We previously demonstrated that CRAM (CRMP5)-associated GTPase (CRAG), a short splicing variant of centaurin-γ3/AGAP3, facilitated degradation of expanded polyglutamine protein (polyQ) via the nuclear ubiquitin-proteasome pathway. Taking advantage of this feature, we also showed that lentivirus-mediated CRAG expression in the Purkinje cells of mice expressing polyQ resulted in clearance of the polyQ aggregates and rescue from ataxia. However, the molecular basis of the function of CRAG in cell survival against polyQ remains unclear. Here we report that CRAG, but not centaurin-γ3, induces transcriptional activation of c-Fos-dependent activator protein-1 (AP-1) via serum response factor (SRF). Mutation analysis indicated that the nuclear localization signal and both the N- and C-terminal regions of CRAG are critical for SRF-dependent c-Fos activation. CRAG knockdown by siRNA or expression of a dominant negative mutant of CRAG significantly attenuated the c-Fos activation triggered by either polyQ or the proteasome inhibitor MG132. Importantly, c-Fos expression partially rescued the enhanced cytotoxicity of CRAG knockdown in polyQ-expressing or MG132-treated cells. Finally, we suggest the possible involvement of CRAG in the sulfiredoxin-mediated antioxidant pathway via AP-1. Taken together, these results demonstrated that CRAG enhances the cell survival signal against the accumulation of unfolded proteins, including polyQ, through not only proteasome activation, but also the activation of c-Fos-dependent AP-1.
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Affiliation(s)
- Shun Nagashima
- Laboratory of Molecular Biochemistry, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, USA
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16
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Mallik M, Lakhotia SC. Modifiers and mechanisms of multi-system polyglutamine neurodegenerative disorders: lessons from fly models. J Genet 2010; 89:497-526. [DOI: 10.1007/s12041-010-0072-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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17
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Rivera-Mancía S, Pérez-Neri I, Ríos C, Tristán-López L, Rivera-Espinosa L, Montes S. The transition metals copper and iron in neurodegenerative diseases. Chem Biol Interact 2010; 186:184-99. [DOI: 10.1016/j.cbi.2010.04.010] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 01/22/2010] [Accepted: 04/08/2010] [Indexed: 12/14/2022]
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18
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Han I, You Y, Kordower JH, Brady ST, Morfini GA. Differential vulnerability of neurons in Huntington's disease: the role of cell type-specific features. J Neurochem 2010; 113:1073-91. [PMID: 20236390 DOI: 10.1111/j.1471-4159.2010.06672.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abnormal expansion of a polyglutamine tract in huntingtin (Htt) protein results in Huntington's disease (HD), an autosomal dominant neurodegenerative disorder involving progressive loss of motor and cognitive function. Contrasting with the ubiquitous tissue expression of polyglutamine-expanded Htt, HD pathology is characterized by the increased vulnerability of specific neuronal populations within the striatum and the cerebral cortex. Morphological, biochemical, and functional characteristics of neurons affected in HD that might render these cells more vulnerable to the toxic effects of polyglutamine-Htt are covered in this review. The differential vulnerability of neurons observed in HD is discussed in the context of various major pathogenic mechanisms proposed to date, and in line with evidence showing a 'dying-back' pattern of degeneration in affected neuronal populations.
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Affiliation(s)
- Ina Han
- Department of Anatomy and Cell Biology. University of Illinois at Chicago, Chicago, Illinois 60612, USA
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19
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20
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Morfini GA, You YM, Pollema SL, Kaminska A, Liu K, Yoshioka K, Björkblom B, Coffey ET, Bagnato C, Han D, Huang CF, Banker G, Pigino G, Brady ST. Pathogenic huntingtin inhibits fast axonal transport by activating JNK3 and phosphorylating kinesin. Nat Neurosci 2009; 12:864-71. [PMID: 19525941 PMCID: PMC2739046 DOI: 10.1038/nn.2346] [Citation(s) in RCA: 187] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Accepted: 05/04/2009] [Indexed: 12/21/2022]
Abstract
Selected vulnerability of neurons in Huntington’s disease (HD) suggests alterations in a cellular process particularly critical for neuronal function. Supporting this idea, pathogenic Htt (polyQ-Htt) inhibits fast axonal transport (FAT) in various cellular and animal HD models (mouse and squid), but the molecular basis of this effect remains unknown. Here we show that polyQ-Htt inhibits FAT through a mechanism involving activation of axonal JNK. Accordingly, increased activation of JNK was observed in vivo in cellular and animal HD models. Additional experiments indicate that polyQ-Htt effects on FAT are mediated by the neuron-specific JNK3, and not ubiquitously expressed JNK1, providing a molecular basis for neuron-specific pathology in HD. Mass spectrometry identified a residue in the kinesin-1 motor domain phosphorylated by JNK3, and this modification reduces kinesin-1 binding to microtubules. These data identify JNK3 as a critical mediator of polyQ-Htt toxicity and provides a molecular basis for polyQ-Htt-induced inhibition of FAT.
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Affiliation(s)
- Gerardo A Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, USA.
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21
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Cytoplasmic inclusions of Htt exon1 containing an expanded polyglutamine tract suppress execution of apoptosis in sympathetic neurons. J Neurosci 2009; 28:14401-15. [PMID: 19118173 DOI: 10.1523/jneurosci.4751-08.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Proteins containing extended polyglutamine repeats cause at least nine neurodegenerative disorders, but the mechanisms of disease-related neuronal death remain uncertain. We show that sympathetic neurons containing cytoplasmic inclusions formed by 97 glutamines expressed within human huntingtin exon1-enhanced green fluorescent protein (Q97) undergo a protracted form of nonapoptotic death that is insensitive to Bax deletion or caspase inhibition but is characterized by mitochondrial dysfunction. By treating the neurons with combined cytosine arabinoside and NGF withdrawal, we demonstrate that Q97 confers a powerful resistance to apoptosis at multiple levels: despite normal proapoptotic signaling (elevation of P-ser15-p53 and BimEL), there is no increase of Puma mRNA or Bax activation, both necessary for apoptosis. Even restoration of Bax translocation with overexpressed Puma does not activate apoptosis. We demonstrate that this robust inhibition of apoptosis is caused by Q97-mediated accumulation of Hsp70, which occurs through inhibition of proteasomal activity. Thus, apoptosis is reinstated by short hairpin RNA-mediated knockdown of Hsp70. These findings explain the rarity of apoptotic death in Q97-expressing neurons. Given the proteasomal blockade, we test whether enhancing lysosomal-mediated degradation with rapamycin reduces Q97 accumulation. Rapamycin reduces the amount of nonpathological Q25 by 70% over 3 d, but Q97 accumulation is unaffected. Interestingly, Q47 inclusions form more slowly as a result of constitutive lysosomal degradation, but faster-forming Q97 inclusions escape lysosomal control. Thus, cytoplasmic Q97 inclusions are refractory to clearance by proteasomal and lysosomal systems, leading to a toxicity that dominates over neuroprotective Hsp70. Our findings may explain the rarity of apoptosis but the inevitable cell death associated with polyQ inclusion diseases.
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22
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Perrin V, Dufour N, Raoul C, Hassig R, Brouillet E, Aebischer P, Luthi-Carter R, Déglon N. Implication of the JNK pathway in a rat model of Huntington's disease. Exp Neurol 2008; 215:191-200. [PMID: 19022249 DOI: 10.1016/j.expneurol.2008.10.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 09/18/2008] [Accepted: 10/16/2008] [Indexed: 11/28/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder resulting from the expansion of a glutamine repeat (polyQ) in the N-terminus of the huntingtin (htt) protein. Expression of polyQ-containing proteins has been previously shown to induce various cellular stress responses. Among these, activation of the c-Jun N-terminal kinase (JNK) cascade has been observed in cellular models of HD. However, the implication of the JNK pathway has not previously been evaluated in the striatum of HD animal models. Here we report that the JNK pathway participates in HD pathology in a rat model of the disease. Increased phosphorylation of the JNK target c-Jun was observed as early as 4 weeks and persisted for 13 weeks after lentiviral-mediated expression of htt171-82Q. In order to assess the importance of this pathway in HD pathology, JNK inhibitors including dominant-negative mutants of upstream kinases (ASK1(K709R), MEKK1(D1369A)), a c-Jun mutant (Delta169c-Jun) and the active domain of the scaffold protein JIP-1/IBI (IBI-JBD) were tested for their ability to mitigate the effect of htt171-82Q. The overexpression of MEKK1(D1369A) and JIP-1/IBI reduced the polyQ-related loss of DARPP-32 expression, while the other inhibitors had no effect. In all cases, the formation of EM48-positive htt inclusions and P-c-Jun immunoreactivity were unaltered. These results suggest that JNK activation is involved in HD and that blockade of this pathway may be of benefit in counteracting HD-related neurotoxicity.
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Affiliation(s)
- V Perrin
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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23
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Robinson P, Lebel M, Cyr M. Dopamine D1 receptor–mediated aggregation of N-terminal fragments of mutant huntingtin and cell death in a neuroblastoma cell line. Neuroscience 2008; 153:762-72. [DOI: 10.1016/j.neuroscience.2008.02.052] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 02/19/2008] [Accepted: 02/23/2008] [Indexed: 10/22/2022]
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24
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Apostol BL, Simmons DA, Zuccato C, Illes K, Pallos J, Casale M, Conforti P, Ramos C, Roarke M, Kathuria S, Cattaneo E, Marsh JL, Thompson LM. CEP-1347 reduces mutant huntingtin-associated neurotoxicity and restores BDNF levels in R6/2 mice. Mol Cell Neurosci 2008; 39:8-20. [PMID: 18602275 DOI: 10.1016/j.mcn.2008.04.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 03/27/2008] [Accepted: 04/11/2008] [Indexed: 01/09/2023] Open
Abstract
Huntington's disease (HD) is a devastating neurodegenerative disorder caused by an expanded polyglutamine repeat within the protein Huntingtin (Htt). We previously reported that mutant Htt expression activates the ERK1/2 and JNK pathways [Apostol, B.L., Illes, K., Pallos, J., Bodai, L., Wu, J., Strand, A., Schweitzer, E.S., Olson, J.M., Kazantsev, A., Marsh, J.L., Thompson, L.M., 2006. Mutant huntingtin alters MAPK signaling pathways in PC12 and striatal cells: ERK1/2 protects against mutant huntingtin-associated toxicity. Hum. Mol. Genet. 15, 273-285]. Chemical and genetic modulation of these pathways promotes cell survival and death, respectively. Here we test the ability of two closely related compounds, CEP-11004 and CEP-1347, which inhibit Mixed Lineage Kinases (MLKs) and are neuroprotective, to suppress mutant Htt-mediated pathogenesis in multiple model systems. CEP-11004/CEP-1347 treatment significantly decreased toxicity in mutant Htt-expressing cells that evoke a strong JNK response. However, suppression of cellular dysfunction in cell lines that exhibit only mild Htt-associated toxicity and little JNK activation was associated with activation of ERK1/2. These compounds also reduced neurotoxicity in immortalized striatal neurons from mutant knock-in mice and Drosophila expressing a mutant Htt fragment. Finally, CEP-1347 improved motor performance in R6/2 mice and restored expression of BDNF, a critical neurotrophic factor that is reduced in HD. These studies suggest a novel therapeutic approach for a currently untreatable neurodegenerative disease, HD, via CEP-1347 up-regulation of BDNF.
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Affiliation(s)
- Barbara L Apostol
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA 92697, USA
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25
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Lee ST, Chu K, Park JE, Hong NH, Im WS, Kang L, Han Z, Jung KH, Kim MW, Kim M. Atorvastatin attenuates mitochondrial toxin-induced striatal degeneration, with decreasing iNOS/c-Jun levels and activating ERK/Akt pathways. J Neurochem 2008; 104:1190-200. [DOI: 10.1111/j.1471-4159.2007.05044.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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26
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Granulocyte-colony stimulating factor attenuates striatal degeneration with activating survival pathways in 3-nitropropionic acid model of Huntington's disease. Brain Res 2008; 1194:130-7. [DOI: 10.1016/j.brainres.2007.11.058] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 11/24/2007] [Accepted: 11/27/2007] [Indexed: 12/11/2022]
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27
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Saudou F, Humbert S. The biology of Huntington's disease. HANDBOOK OF CLINICAL NEUROLOGY 2008; 89:619-29. [DOI: 10.1016/s0072-9752(07)01257-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Scappini E, Koh TW, Martin NP, O'Bryan JP. Intersectin enhances huntingtin aggregation and neurodegeneration through activation of c-Jun-NH2-terminal kinase. Hum Mol Genet 2007; 16:1862-71. [PMID: 17550941 DOI: 10.1093/hmg/ddm134] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Huntingon's disease is a progressive neurodegenerative disease arising from expansion of a polyglutamine (polyQ) tract in the protein huntingtin (Htt) resulting in aggregation of mutant Htt into nuclear and/or cytosolic inclusions in neurons. Mutant Htt affects multiple processes including protein degradation, transcription, signal transduction, fast axonal transport and endocytosis [reviewed in Ross, C.A. and Poirier, M.A. (2005) Opinion: what is the role of protein aggregation in neurodegeneration? Nat. Rev. Mol. Cell. Biol., 6, 891-898]. Here, we report that the endocytic and signal transduction scaffold intersectin (ITSN) increased aggregate formation by mutant Htt through activation of the c-Jun-NH(2)-terminal kinase (JNK)-MAPK pathway. Conversely, silencing ITSN or inhibiting JNK attenuated aggregate formation. Using a Drosophila model for polyQ repeat disease, we observed that ITSN enhanced polyQ-mediated neurotoxicity. A reciprocal relationship was observed between ITSN and Htt. While ITSN enhanced Htt aggregation and toxicity, Htt, in turn, inhibited the cooperativity between ITSN and the epidermal growth factor receptor signal transduction pathway. Finally, we observed that ITSN overexpression enhanced aggregation of polyQ-expanded androgen receptor (AR) as well as wild-type versions of both Htt and AR suggesting a broader involvement of ITSN in neurodegenerative diseases through destabilization of polyQ-containing proteins.
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Affiliation(s)
- Erica Scappini
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
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Merienne K, Friedman J, Akimoto M, Abou-Sleymane G, Weber C, Swaroop A, Trottier Y. Preventing polyglutamine-induced activation of c-Jun delays neuronal dysfunction in a mouse model of SCA7 retinopathy. Neurobiol Dis 2006; 25:571-81. [PMID: 17189700 PMCID: PMC1858671 DOI: 10.1016/j.nbd.2006.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Revised: 10/27/2006] [Accepted: 11/01/2006] [Indexed: 11/23/2022] Open
Abstract
We have approached the role of cellular stress in neurodegenerative diseases caused by polyglutamine expansion (polyQ) in the context of Spinocerebellar ataxia type 7 (SCA7) that includes retinal degeneration. Using the R7E mouse, in which polyQ-ataxin-7 is specifically over-expressed in rod photoreceptors, we previously showed that rod dysfunction correlated to moderate and prolonged activation of the JNK/c-Jun stress pathway. SCA7 retinopathy was also associated with reduced expression of rod-specific genes, including the transcription factor Nrl, which is essential for rod differentiation and function. Here, we report that R7E retinopathy is improved upon breeding with the JunAA knock-in mice, in which JNK-mediated activation of c-Jun is compromised. Expression of Nrl and its downstream targets, which are involved in phototranduction, are partially restored in the JunAA-R7E mice. We further show that c-Jun can directly repress the transcription of Nrl. Our studies suggest that polyQ-induced cellular stress leads to repression of genes necessary for neuronal fate and function.
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Affiliation(s)
- Karine Merienne
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg
- Chaire de Génétique Humaine, Collège de France
| | - James Friedman
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Masayuki Akimoto
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
- Translational Research Center, Kyoto University Hospital, Japan
| | - Gretta Abou-Sleymane
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg
- Chaire de Génétique Humaine, Collège de France
| | - Chantal Weber
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg
- Chaire de Génétique Humaine, Collège de France
| | - Anand Swaroop
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
- Department of Human Genetics, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Yvon Trottier
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg
- Chaire de Génétique Humaine, Collège de France
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Colby DW, Cassady JP, Lin GC, Ingram VM, Wittrup KD. Stochastic kinetics of intracellular huntingtin aggregate formation. Nat Chem Biol 2006; 2:319-23. [PMID: 16699519 DOI: 10.1038/nchembio792] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 04/14/2006] [Indexed: 11/09/2022]
Abstract
Neurodegeneration in Huntington disease is described by neuronal loss in which the probability of cell death remains constant with time. However, the quantitative connection between the kinetics of cell death and the molecular mechanism initiating neurodegeneration remains unclear. One hypothesis is that nucleation of protein aggregates containing exon I fragments of the mutant huntingtin protein (mhttex1), which contains an expanded polyglutamine region in patients with the disease, is the explanation for the infrequent but steady occurrence of neuronal death, resulting in adult onset of the disease. Recent in vitro evidence suggests that sufficiently long polyglutamine peptides undergo a unimolecular conformational change to form a nucleus that seeds aggregation. Here we use this nucleation mechanism as the basis to derive a stochastic mathematical model describing the probability of aggregate formation in cells as a function of time and mhttex1 protein concentration, and validate the model experimentally. These findings suggest that therapeutic strategies for Huntington disease predicated on reducing the rate of mhttex1 aggregation need only make modest reductions in huntingtin expression level to substantially increase the delay time until aggregate formation.
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Affiliation(s)
- David W Colby
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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31
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Apostol BL, Illes K, Pallos J, Bodai L, Wu J, Strand A, Schweitzer ES, Olson JM, Kazantsev A, Marsh JL, Thompson LM. Mutant huntingtin alters MAPK signaling pathways in PC12 and striatal cells: ERK1/2 protects against mutant huntingtin-associated toxicity. Hum Mol Genet 2005; 15:273-85. [PMID: 16330479 DOI: 10.1093/hmg/ddi443] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Huntington's disease (HD) is a devastating neurodegenerative disorder caused by an expanded polyglutamine (polyQ) tract within the huntingtin protein (Htt). Identifying the pathways that are altered in response to the mutant protein is crucial for understanding the cellular processes impacted by the disease as well as for the rational development of effective pharmacological interventions. Here, expression profiling of a cellular HD model identifies genes that implicate altered mitogen-activated protein kinase (MAPK) signaling. Targeted biochemical studies and pharmacological modulation of these MAPK pathways suggest that mutant Htt affects signaling at upstream points such that both ERK and JNK are activated. Modulation of the ERK pathway suggests that this pathway is associated with cell survival, whereas inhibition of JNK was found to effectively suppress pathogenesis. These studies suggest that pharmacological intervention in MAPK pathways, particularly at the level of ERK activation, may be an appropriate approach to HD therapy.
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Affiliation(s)
- Barbara L Apostol
- Department of Psychiatry and Human Behavior, University of California, Irvine, 92697, USA
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Brouillet E, Jacquard C, Bizat N, Blum D. 3-Nitropropionic acid: a mitochondrial toxin to uncover physiopathological mechanisms underlying striatal degeneration in Huntington's disease. J Neurochem 2005; 95:1521-40. [PMID: 16300642 DOI: 10.1111/j.1471-4159.2005.03515.x] [Citation(s) in RCA: 269] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a mutation in the gene encoding Huntingtin. The mechanisms underlying the preferential degeneration of the striatum, the most striking neuropathological change in HD, are unknown. Of those probably involved, mitochondrial defects might play an important role. The behavioural and anatomical similarities found between HD and models using the mitochondrial toxin 3-nitropropionic acid (3NP) in rats and primates support this hypothesis. Here, we discuss the recently identified mechanisms of 3NP-induced striatal degeneration. Two types of important factor have been identified. The first are the 'executioner' components that have direct roles in cell death, such as c-Jun N-terminal kinase and Ca2+-activated protease calpains. The second are 'environmental' factors, such as glutamate, dopamine and adenosine, which modulate the striatal degeneration induced by 3NP. Interestingly, these recent studies support the hypothesis that 3NP and mutated Huntingtin have certain mechanisms of toxicity in common, suggesting that the use of 3NP might give new insights into the pathogenesis of HD. Research on 3NP provides additional proof that the neurochemical environment of a given neurone can determine its preferential vulnerability in neurodegenerative diseases.
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Affiliation(s)
- Emmanuel Brouillet
- Centre Nationale de la Recherche Scientifique 2210, Service Hospitalier Frédéric Joliot, Départment de Recherches Médicales, Direction des Sciences du Vivant, CEA, Orsay France.
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Charvin D, Vanhoutte P, Pagès C, Borrelli E, Borelli E, Caboche J. Unraveling a role for dopamine in Huntington's disease: the dual role of reactive oxygen species and D2 receptor stimulation. Proc Natl Acad Sci U S A 2005; 102:12218-23. [PMID: 16103364 PMCID: PMC1189314 DOI: 10.1073/pnas.0502698102] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Huntington's disease (HD), an inherited neurodegenerative disorder, results from an abnormal polyglutamine extension in the N-terminal region of the huntingtin protein. This mutation leads to protein aggregation and neurotoxicity. Despite its widespread expression in the brain and body, mutated huntingtin causes selective degeneration of striatal projection neurons. In the present study, we investigate the role of dopamine (DA) in this preferential vulnerability. Using primary cultures of striatal neurons transiently expressing GFP-tagged-exon 1 of mutated huntingtin, we show that low doses of DA (100 microM) act synergistically with mutated huntingtin to activate the proapoptotic transcription factor c-Jun. Surprisingly, DA also increases aggregate formation of mutated huntingtin in all cellular compartments, including neurites, soma, and nuclei. DA-dependent potentiation of c-Jun activation was reversed by ascorbate, a reactive oxygen species (ROS) scavenger, and SP-600125, a selective inhibitor of the c-Jun N-terminal kinase (JNK) pathway. By contrast, DA effects on aggregate formation were reversed by a selective D2 receptor antagonist and reproduced by a D2 agonist. Similarly, striatal neurons from D2 knockout mice showed no effect of DA on aggregate formation. Blocking ROS production, JNK activation, or D2 receptor stimulation significantly reversed DA aggravation of mutated huntingtin-induced striatal death. The combined treatment with the ROS scavenger and D2 antagonist totally reversed DA's effects on mutated huntingtin-induced striatal death. Thus, the present results provide insights into the cellular mechanisms that govern striatal vulnerability in HD and strongly support a dual role of JNK activation and D2 receptor signaling in this process.
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Affiliation(s)
- Delphine Charvin
- Unité Mixte de Recherche 7102, Signalisation Neuronale et Régulations Géniques, 9 Quai Saint Bernard, 75005 Paris, France
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