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Subramaniam S, Boregowda S. Curbing Rhes Actions: Mechanism-based Molecular Target for Huntington's Disease and Tauopathies. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:21-29. [PMID: 36959146 DOI: 10.2174/1871527322666230320103518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 03/25/2023]
Abstract
A highly interconnected network of diverse brain regions is necessary for the precise execution of human behaviors, including cognitive, psychiatric, and motor functions. Unfortunately, degeneration of specific brain regions causes several neurodegenerative disorders, but the mechanisms that elicit selective neuronal vulnerability remain unclear. This knowledge gap greatly hinders the development of effective mechanism-based therapies, despite the desperate need for new treatments. Here, we emphasize the importance of the Rhes (Ras homolog-enriched in the striatum) protein as an emerging therapeutic target. Rhes, an atypical small GTPase with a SUMO (small ubiquitin-like modifier) E3-ligase activity, modulates biological processes such as dopaminergic transmission, alters gene expression, and acts as an inhibitor of motor stimuli in the brain striatum. Mutations in the Rhes gene have also been identified in selected patients with autism and schizophrenia. Moreover, Rhes SUMOylates pathogenic form of mutant huntingtin (mHTT) and tau, enhancing their solubility and cell toxicity in Huntington's disease and tauopathy models. Notably, Rhes uses membrane projections resembling tunneling nanotubes to transport mHTT between cells and Rhes deletion diminishes mHTT spread in the brain. Thus, we predict that effective strategies aimed at diminishing brain Rhes levels will prevent or minimize the abnormalities that occur in HD and tauopathies and potentially in other brain disorders. We review the emerging technologies that enable specific targeting of Rhes in the brain to develop effective disease-modifying therapeutics.
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Affiliation(s)
- Srinivasa Subramaniam
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, 130 Scripps Way, C323, Florida, Jupiter, 33458, USA
| | - Siddaraju Boregowda
- Department of Molecular Therapeutics, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, 130 Scripps Way, C323, Florida, Jupiter, 33458, USA
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Jiang A, Handley RR, Lehnert K, Snell RG. From Pathogenesis to Therapeutics: A Review of 150 Years of Huntington's Disease Research. Int J Mol Sci 2023; 24:13021. [PMID: 37629202 PMCID: PMC10455900 DOI: 10.3390/ijms241613021] [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: 07/28/2023] [Revised: 08/15/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
Huntington's disease (HD) is a debilitating neurodegenerative genetic disorder caused by an expanded polyglutamine-coding (CAG) trinucleotide repeat in the huntingtin (HTT) gene. HD behaves as a highly penetrant dominant disorder likely acting through a toxic gain of function by the mutant huntingtin protein. Widespread cellular degeneration of the medium spiny neurons of the caudate nucleus and putamen are responsible for the onset of symptomology that encompasses motor, cognitive, and behavioural abnormalities. Over the past 150 years of HD research since George Huntington published his description, a plethora of pathogenic mechanisms have been proposed with key themes including excitotoxicity, dopaminergic imbalance, mitochondrial dysfunction, metabolic defects, disruption of proteostasis, transcriptional dysregulation, and neuroinflammation. Despite the identification and characterisation of the causative gene and mutation and significant advances in our understanding of the cellular pathology in recent years, a disease-modifying intervention has not yet been clinically approved. This review includes an overview of Huntington's disease, from its genetic aetiology to clinical presentation and its pathogenic manifestation. An updated view of molecular mechanisms and the latest therapeutic developments will also be discussed.
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Affiliation(s)
- Andrew Jiang
- Applied Translational Genetics Group, Centre for Brain Research, School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand; (R.R.H.); (K.L.); (R.G.S.)
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Pan Y, Tang B, Li XJ, Li S, Liu Q. Rhes depletion promotes striatal accumulation and aggregation of mutant huntingtin in a presymptomatic HD mouse model. Front Aging Neurosci 2023; 15:1237018. [PMID: 37637962 PMCID: PMC10449645 DOI: 10.3389/fnagi.2023.1237018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/31/2023] [Indexed: 08/29/2023] Open
Abstract
Introduction Huntington's disease (HD) is caused by CAG trinucleotide repeats in the HTT gene. Selective neurodegeneration in the striatum is prominent in HD, despite widespread expression of mutant HTT (mHTT). Ras homolog enriched in the striatum (Rhes) is a GTP-binding protein enriched in the striatum, involved in dopamine-related behaviors and autophagy regulation. Growing evidence suggests Rhes plays a critical role in the selective striatal degeneration in HD, but its specific function in this context remains complex and controversial. Methods In this study, we utilized CRISPR/Cas9 to knockdown Rhes at different disease stages through adeno-associated virus (AAV) transduction in HD knock-in (KI) mice. Immunoblotting and immunofluorescence were employed to assess the impact of Rhes depletion on mHTT levels, neuronal loss, astrogliosis and autophagy activity. Results Rhes depletion in 22-week-old HD KI mice (representing the presymptomatic stage) led to mHTT accumulation, reduced neuronal cell staining, and increased astrogliosis. However, no such effects were observed in 36-week-old HD KI mice (representing the symptomatic stage). Additionally, Rhes deletion in 22-week-old HD KI mice resulted in increased P62 levels, reduced LC3-II levels, and unchanged phosphorylation of mTOR and beclin-1, unchanged mTOR protein level, except for a decrease in beclin-1. Discussion Our findings suggest that knockdown Rhes promotes striatal aggregation of mutant huntingtin by reducing autophagy activity in a mTOR-independent manner. Rhes plays a protective role during the presymptomatic stage of HD KI mice.
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Affiliation(s)
- Yongcheng Pan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiao-Jiang Li
- Guangdong Key Laboratory of Non-human Primate Research, Key Laboratory of CNS Regeneration (Ministry of Education), GHM Institute of CNS Regeneration, Jinan University, Guangzhou, China
| | - Shihua Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Guangdong Key Laboratory of Non-human Primate Research, Key Laboratory of CNS Regeneration (Ministry of Education), GHM Institute of CNS Regeneration, Jinan University, Guangzhou, China
| | - Qiong Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
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Subramaniam S. Striatal Induction and Spread of the Huntington’s Disease Protein: A Novel Rhes Route. J Huntingtons Dis 2022; 11:281-290. [PMID: 35871361 PMCID: PMC9484121 DOI: 10.3233/jhd-220548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The CAG/CAA expansion encoding polyQ huntingtin (mutant huntingtin [mHTT]) causes Huntington’s disease (HD), which is characterized by atrophy and loss of striatal medium spiny neurons (MSNs), which are preceded by neuropathological alterations in the cortex. Previous studies have shown that mHTT can spread in the brain, but the mechanisms involved in the stereotyped degeneration and dysfunction of the neurons from the striatum to the cortex remain unclear. In this study, we found that the mHTT expression initially restricted in the striatum later spread to the cortical regions in mouse brains. Such transmission was diminished in mice that lacked the striatal-enriched protein Ras-homolog enriched in the striatum (Rhes). Rhes restricted to MSNs was also found in the cortical layers of the brain, indicating a new transmission route for the Rhes protein to the brain. Mechanistically, Rhes promotes such transmission via a direct cell-to-cell contact mediated by tunneling nanotubes (TNTs), the membranous protrusions that enable the transfer of mHTT, Rhes, and other vesicular cargoes. These transmission patterns suggest that Rhes and mHTT are likely co-transported in the brain using TNT-like cell-to-cell contacts. On the basis of these new results, a perspective is presented in this review: Rhes may ignite the mHTT transmission from the striatum that may coincide with HD onset and disease progression through an anatomically connected striato-cortical retrograde route.
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5
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Milanesi E, Cucos CA, Matias-Guiu JA, Piñol-Ripoll G, Manda G, Dobre M, Cuadrado A. Reduced Blood RGS2 Expression in Mild Cognitive Impairment Patients. Front Aging Neurosci 2021; 13:738244. [PMID: 34658840 PMCID: PMC8513788 DOI: 10.3389/fnagi.2021.738244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/08/2021] [Indexed: 11/30/2022] Open
Abstract
Regulator of G protein signaling 2 (RGS2) is a gene involved in neuronal plasticity and synaptic signaling, whose expression in the brain is altered in neuropsychiatric and neurodegenerative disorders. Microarray data from large datasets suggested reduced RGS2 mRNA levels in the post-mortem brain tissue and blood of Alzheimer’s disease (AD) patients. The results were previously confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) only ex vivo in lymphoblastoid cell lines derived from AD patients and controls. In this study, we compared RGS2 mRNA levels in peripheral blood samples from 69 mild cognitive impairment (MCI) patients to 50 age- and sex-matched non-cognitively impaired controls, out of which 25 patients were monitored at 1 year. We found that RGS2 was indeed downregulated in the peripheral blood of these patients (FR = −1.60, p < 0.001), and despite disease-specific therapy, RGS2 transcript levels continued to decrease at 1 year. The results suggest that RGS2 seems to be involved in AD pathology and progression and can be introduced in a panel of blood AD biomarkers.
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Affiliation(s)
- Elena Milanesi
- "Victor Babes" National Institute of Pathology, Bucharest, Romania
| | | | - Jordi A Matias-Guiu
- Department of Neurology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Universidad Complutense, Madrid, Spain
| | - Gerard Piñol-Ripoll
- Unitat Trastons Cognitius, Hospital Universitari Santa Maria-IRBL Leida, Lleida, Spain
| | - Gina Manda
- "Victor Babes" National Institute of Pathology, Bucharest, Romania
| | - Maria Dobre
- "Victor Babes" National Institute of Pathology, Bucharest, Romania
| | - Antonio Cuadrado
- "Victor Babes" National Institute of Pathology, Bucharest, Romania.,Department of Endocrine Physiology and Nervous System, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC, Madrid, Spain.,Faculty of Medicine, Department of Biochemistry, Autonomous University of Madrid, Madrid, Spain.,Neuroscience Section, Instituto de Investigación Sanitaria La Paz (IdiPaz), Madrid, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
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6
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Heikkinen T, Bragge T, Kuosmanen J, Parkkari T, Gustafsson S, Kwan M, Beltran J, Ghavami A, Subramaniam S, Shahani N, Ramírez-Jarquín UN, Park L, Muñoz-Sanjuán I, Marchionini DM. Global Rhes knockout in the Q175 Huntington's disease mouse model. PLoS One 2021; 16:e0258486. [PMID: 34648564 PMCID: PMC8516231 DOI: 10.1371/journal.pone.0258486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/28/2021] [Indexed: 12/02/2022] Open
Abstract
Huntington’s disease (HD) results from an expansion mutation in the polyglutamine tract in huntingtin. Although huntingtin is ubiquitously expressed in the body, the striatum suffers the most severe pathology. Rhes is a Ras-related small GTP-binding protein highly expressed in the striatum that has been reported to modulate mTOR and sumoylation of mutant huntingtin to alter HD mouse model pathogenesis. Reports have varied on whether Rhes reduction is desirable for HD. Here we characterize multiple behavioral and molecular endpoints in the Q175 HD mouse model with genetic Rhes knockout (KO). Genetic RhesKO in the Q175 female mouse resulted in both subtle attenuation of Q175 phenotypic features, and detrimental effects on other kinematic features. The Q175 females exhibited measurable pathogenic deficits, as measured by MRI, MRS and DARPP32, however, RhesKO had no effect on these readouts. Additionally, RhesKO in Q175 mixed gender mice deficits did not affect mTOR signaling, autophagy or mutant huntingtin levels. We conclude that global RhesKO does not substantially ameliorate or exacerbate HD mouse phenotypes in Q175 mice.
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Affiliation(s)
| | - Timo Bragge
- Charles River Discovery Services, Kuopio, Finland
| | | | | | | | - Mei Kwan
- Psychogenics, Paramus, New Jersey, United States of America
| | - Jose Beltran
- Psychogenics, Paramus, New Jersey, United States of America
| | - Afshin Ghavami
- Psychogenics, Paramus, New Jersey, United States of America
| | - Srinivasa Subramaniam
- The Scripps Research Institute, Department of Neuroscience, Jupiter, Florida, United States of America
| | - Neelam Shahani
- The Scripps Research Institute, Department of Neuroscience, Jupiter, Florida, United States of America
| | | | - Larry Park
- CHDI Management/CHDI Foundation, New York, New York, United States of America
| | | | - Deanna M. Marchionini
- CHDI Management/CHDI Foundation, New York, New York, United States of America
- * E-mail:
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Eshraghi M, Karunadharma PP, Blin J, Shahani N, Ricci EP, Michel A, Urban NT, Galli N, Sharma M, Ramírez-Jarquín UN, Florescu K, Hernandez J, Subramaniam S. Mutant Huntingtin stalls ribosomes and represses protein synthesis in a cellular model of Huntington disease. Nat Commun 2021; 12:1461. [PMID: 33674575 PMCID: PMC7935949 DOI: 10.1038/s41467-021-21637-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 01/29/2021] [Indexed: 02/08/2023] Open
Abstract
The polyglutamine expansion of huntingtin (mHTT) causes Huntington disease (HD) and neurodegeneration, but the mechanisms remain unclear. Here, we found that mHtt promotes ribosome stalling and suppresses protein synthesis in mouse HD striatal neuronal cells. Depletion of mHtt enhances protein synthesis and increases the speed of ribosomal translocation, while mHtt directly inhibits protein synthesis in vitro. Fmrp, a known regulator of ribosome stalling, is upregulated in HD, but its depletion has no discernible effect on protein synthesis or ribosome stalling in HD cells. We found interactions of ribosomal proteins and translating ribosomes with mHtt. High-resolution global ribosome footprint profiling (Ribo-Seq) and mRNA-Seq indicates a widespread shift in ribosome occupancy toward the 5' and 3' end and unique single-codon pauses on selected mRNA targets in HD cells, compared to controls. Thus, mHtt impedes ribosomal translocation during translation elongation, a mechanistic defect that can be exploited for HD therapeutics.
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Affiliation(s)
- Mehdi Eshraghi
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Pabalu P. Karunadharma
- grid.214007.00000000122199231The Scripps Research Institute, Genomic Core, Jupiter, FL USA
| | - Juliana Blin
- grid.462957.b0000 0004 0598 0706Laboratory of Biology and Cellular Modelling at Ecole Normale Supérieure of Lyon, RNA Metabolism in Immunity and Infection Lab, LBMC, Lyon, France
| | - Neelam Shahani
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Emiliano P. Ricci
- grid.462957.b0000 0004 0598 0706Laboratory of Biology and Cellular Modelling at Ecole Normale Supérieure of Lyon, RNA Metabolism in Immunity and Infection Lab, LBMC, Lyon, France
| | | | | | - Nicole Galli
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Manish Sharma
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Uri Nimrod Ramírez-Jarquín
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Katie Florescu
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Jennifer Hernandez
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Srinivasa Subramaniam
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
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8
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Han S, Fei F, Sun S, Zhang D, Dong Q, Wang X, Wang L. Increased anxiety was found in serpini1 knockout zebrafish larval. Biochem Biophys Res Commun 2021; 534:1013-1019. [PMID: 33168193 DOI: 10.1016/j.bbrc.2020.10.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022]
Abstract
Serpini1, which encodes neuroserpin, has been implicated in the development and normal function of the nervous system. Mutations in serpini1 cause familial encephalopathy, a rare neurodegenerative disorder characterized with neuroserpin inclusion bodies. However, function of neuroserpin in the nervous system is not fully understood. In this study, we generated a novel serpini1 mutant zebrafish model to investigate the loss of function of neuroserpin. Serpini1- deficient mutation was created with the CRISPR/Cas9 technique. No severe morphological characteristics were found in serpini1- deficient zebrafish. Serpini1-/- zebrafish larvae did not cause locomotor defects but displayed anxiety-like behavior. Extension of motoneurons axon defect was observed in serpini1-/- zebrafish. Furthermore, RNA-sequencing analysis revealed that loss of serpini1 resulted in affected expression of neurodegeneration-related genes.
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Affiliation(s)
- Sha Han
- Department of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, People's Republic of China
| | - Fei Fei
- Nanjing Drum Tower Hospital, 321 Zhongshan Road, Nanjing, 210008, People's Republic of China
| | - Shaoyang Sun
- Key Laboratory of Metabolism and Molecular Medicine, Ministry Education, Department of Biochemistry and Molecular Biology School of Basic Medical Sciences, Fudan University, Shanghai, 200032, People's Republic of China
| | - Dongyang Zhang
- Department of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, People's Republic of China
| | - Qiang Dong
- Department of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, People's Republic of China
| | - Xu Wang
- Cancer Metabolism Laboratory, Cancer Research Institute Fudan University Shanghai Cancer Center, Shanghai, 200032, People's Republic of China
| | - Liang Wang
- Department of Neurology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, People's Republic of China.
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Mitchell CT, Krier I, Arjomand J, Borowsky B, Tabrizi SJ, Leavitt BR, Luthi-Carter R. Longitudinal expression changes are weak correlates of disease progression in Huntington's disease. Brain Commun 2020; 2:fcaa172. [PMID: 33305259 PMCID: PMC7713990 DOI: 10.1093/braincomms/fcaa172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 08/31/2020] [Accepted: 09/16/2020] [Indexed: 11/15/2022] Open
Abstract
Huntington's disease is a severe but slowly progressive hereditary illness for which only symptomatic treatments are presently available. Clinical measures of disease progression are somewhat subjective and may require years to detect significant change. There is a clear need to identify more sensitive, objective and consistent measures to detect disease progression in Huntington's disease clinical trials. Whereas Huntington's disease demonstrates a robust and consistent gene expression signature in the brain, previous studies of blood cell RNAs have lacked concordance with clinical disease stage. Here we utilized longitudinally collected samples from a well-characterized cohort of control, Huntington's disease-at-risk and Huntington's disease subjects to evaluate the possible correlation of gene expression and disease status within individuals. We interrogated these data in both cross-sectional and longitudinal analyses. A number of changes in gene expression showed consistency within this study and as compared to previous reports in the literature. The magnitude of the mean disease effect over 2 years' time was small, however, and did not track closely with motor symptom progression over the same time period. We therefore conclude that while blood-derived gene expression indicators can be of value in understanding Huntington's disease pathogenesis, they are insufficiently sensitive to be of use as state biomarkers.
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Affiliation(s)
- Christopher T Mitchell
- University of Leicester, University Road, Leicester LE1 7RH, UK
- School of Medicine, King's College London, London, UK
| | - Irina Krier
- École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | | | | | - Sarah J Tabrizi
- UCL Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Dementia Research Institute at UCL, Huntington's Disease Centre, London WC1N 3BG, UK
| | - Blair R Leavitt
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada 75Z 4H4
| | - Ruth Luthi-Carter
- University of Leicester, University Road, Leicester LE1 7RH, UK
- School of Medicine, King's College London, London, UK
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Loss of Hap1 selectively promotes striatal degeneration in Huntington disease mice. Proc Natl Acad Sci U S A 2020; 117:20265-20273. [PMID: 32747555 DOI: 10.1073/pnas.2002283117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Huntington disease (HD) is an ideal model for investigating selective neurodegeneration, as expanded polyQ repeats in the ubiquitously expressed huntingtin (HTT) cause the preferential neurodegeneration in the striatum of the HD patient brains. Here we report that adeno-associated virus (AAV) transduction-mediated depletion of Hap1, the first identified huntingtin-associated protein, in adult HD knock-in (KI) mouse brains leads to selective neuronal loss in the striatum. Further, Hap1 depletion-mediated neuronal loss via AAV transduction requires the presence of mutant HTT. Rhes, a GTPase that is enriched in the striatum and sumoylates mutant HTT to mediate neurotoxicity, binds more N-terminal HTT when Hap1 is deficient. Consistently, more soluble and sumoylated N-terminal HTT is presented in HD KI mouse striatum when HAP1 is absent. Our findings suggest that both Rhes and Hap1 as well as cellular stress contribute to the preferential neurodegeneration in HD, highlighting the involvement of multiple factors in selective neurodegeneration.
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Subramaniam S. Rhes Tunnels: A Radical New Way of Communication in the Brain's Striatum? Bioessays 2020; 42:e1900231. [PMID: 32236969 PMCID: PMC7310467 DOI: 10.1002/bies.201900231] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/13/2020] [Indexed: 12/11/2022]
Abstract
Ras homolog enriched in the striatum (Rhes) is a striatal enriched protein that promotes the formation of thin membranous tubes resembling tunneling nanotubes (TNT)-"Rhes tunnels"-that connect neighboring cell and transport cargoes: vesicles and proteins between the neuronal cells. Here the literature on TNT-like structures is reviewed, and the implications of Rhes-mediated TNT, the mechanisms of its formation, and its potential in novel cell-to-cell communication in regulating striatal biology and disease are emphasized. Thought-provoking ideas regarding how Rhes-mediated TNT, if it exists, in vivo, would radically change the way neurons communicate in the brain are discussed.
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12
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Subramaniam S. Exaggerated mitophagy: a weapon of striatal destruction in the brain? Biochem Soc Trans 2020; 48:709-717. [PMID: 32129826 PMCID: PMC7200642 DOI: 10.1042/bst20191283] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/13/2020] [Accepted: 02/14/2020] [Indexed: 12/16/2022]
Abstract
Mechanisms responsible for neuronal vulnerability in the brain remain unclear. Striatal neurons are preferentially damaged by 3-nitropropionic acid (3-NP), a mitochondrial complex-II inhibitor, causing striatal damage reminiscent of Huntington's disease (HD), but the mechanisms of the selectivity are not as well understood. We have discovered that Rhes, a protein enriched in the striatum, removes mitochondria via the mitophagy process. The process becomes intensified in the presence of 3-NP, thereby eliminating most of the mitochondria from the striatum. We put forward the hypothesis that Rhes acts as a 'mitophagy ligand' in the brain and promotes mitophagy via NIX, a mitophagy receptor. Since Rhes interacts and promotes toxicity in association with mutant huntingtin (mHTT), the genetic cause of HD, it is tempting to speculate on whether the exaggerated mitophagy may be a contributing factor to the striatal lesion found in HD. Thus, Rhes-mediated exaggerated mitophagy may act as a weapon of striatal destruction in the brain.
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Affiliation(s)
- Srinivasa Subramaniam
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, U.S.A
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13
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Abstract
Elimination of dysfunctional mitochondria via mitophagy is essential for cell survival and neuronal functions. But, how impaired mitophagy participates in tissue-specific vulnerability in the brain remains unclear. Here, we find that striatal-enriched protein, Rhes, is a critical regulator of mitophagy and striatal vulnerability in brain. In vivo interactome and density fractionation reveal that Rhes coimmunoprecipitates and cosediments with mitochondrial and lysosomal proteins. Live-cell imaging of cultured striatal neuronal cell line shows Rhes surrounds globular mitochondria, recruits lysosomes, and ultimately degrades mitochondria. In the presence of 3-nitropropionic acid (3-NP), an inhibitor of succinate dehydrogenase, Rhes disrupts mitochondrial membrane potential (ΔΨ m ) and promotes excessive mitophagy and cell death. Ultrastructural analysis reveals that systemic injection of 3-NP in mice promotes globular mitochondria, accumulation of mitophagosomes, and striatal lesion only in the wild-type (WT), but not in the Rhes knockout (KO), striatum, suggesting that Rhes is critical for mitophagy and neuronal death in vivo. Mechanistically, Rhes requires Nix (BNIP3L), a known receptor of mitophagy, to disrupt ΔΨ m and promote mitophagy and cell death. Rhes interacts with Nix via SUMO E3-ligase domain, and Nix depletion totally abrogates Rhes-mediated mitophagy and cell death in the cultured striatal neuronal cell line. Finally, we find that Rhes, which travels from cell to cell via tunneling nanotube (TNT)-like cellular protrusions, interacts with dysfunctional mitochondria in the neighboring cell in a Nix-dependent manner. Collectively, Rhes is a major regulator of mitophagy via Nix, which may determine striatal vulnerability in the brain.
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14
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Carbo M, Brandi V, Pascarella G, Staid DS, Colotti G, Polticelli F, Ilari A, Morea V. Bioinformatics analysis of Ras homologue enriched in the striatum, a potential target for Huntington's disease therapy. Int J Mol Med 2019; 44:2223-2233. [PMID: 31638189 PMCID: PMC6844632 DOI: 10.3892/ijmm.2019.4373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 08/19/2019] [Indexed: 11/15/2022] Open
Abstract
Huntington's disease (HD) is a lethal neurodegenerative disorder for which no cure is available yet. It is caused by abnormal expansion of a CAG triplet in the gene encoding the huntingtin protein (Htt), with consequent expansion of a polyglutamine repeat in mutated Htt (mHtt). This makes mHtt highly unstable and aggregation prone. Soluble mHtt is linked to cytotoxicity and neurotoxicity, whereas mHtt aggregates are thought to be neuroprotective. While Htt and mHtt are ubiquitously expressed throughout the brain and peripheral tissues, HD is characterized by selective degradation of the corpus striatum, without notable alterations in peripheral tissues. Screening for mRNAs preferentially expressed in rodent striatum led to the discovery of a GTP binding protein homologous to Ras family members. Due to these features, the newly discovered protein was termed Ras Homolog Enriched in Striatum (RHES). The aetiological role of RHES in HD has been ascribed to its small ubiquitin-like modifier (SUMO)-E3 ligase function. RHES sumoylates mHtt with higher efficiency than wild-type Htt, thereby protecting mHtt from degradation and increasing the amounts of the soluble form. Although RHES is an attractive target for HD treatment, essential information about protein structure and function are still missing. With the aim of investigating RHES 3D structure and function, bioinformatic analyses and molecular modelling have been performed in the present study, based on which, RHES regions predicted to be involved in the interaction with mHtt or the SUMO-E2 ligase Ubc9 have been identified. These regions have been used to design peptides aimed at inhibiting RHES interactions and, therefore, mHtt sumoylation; in turn, these peptides will be used to develop small molecule inhibitors by both rational design and virtual screening of large compound libraries. Once identified, RHES sumoylation inhibitors may open the road to the development of therapeutic agents against the severe, and currently untreatable, HD.
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Affiliation(s)
- Miriam Carbo
- Department of Biochemical Sciences 'A. Rossi Fanelli', Sapienza University, I‑00185 Rome, Italy
| | - Valentina Brandi
- Department of Sciences, Roma Tre University, I‑00159 Rome, Italy
| | - Gianmarco Pascarella
- Department of Biochemical Sciences 'A. Rossi Fanelli', Sapienza University, I‑00185 Rome, Italy
| | - David Sasah Staid
- Department of Biochemical Sciences 'A. Rossi Fanelli', Sapienza University, I‑00185 Rome, Italy
| | - Gianni Colotti
- Institute of Molecular Biology and Pathology of The National Research Council of Italy, I‑00185 Rome, Italy
| | - Fabio Polticelli
- Department of Sciences, Roma Tre University, I‑00159 Rome, Italy
| | - Andrea Ilari
- Institute of Molecular Biology and Pathology of The National Research Council of Italy, I‑00185 Rome, Italy
| | - Veronica Morea
- Institute of Molecular Biology and Pathology of The National Research Council of Italy, I‑00185 Rome, Italy
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15
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Dong X, Cong S. The Emerging Role of microRNAs in Polyglutamine Diseases. Front Mol Neurosci 2019; 12:156. [PMID: 31275113 PMCID: PMC6593396 DOI: 10.3389/fnmol.2019.00156] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 06/04/2019] [Indexed: 12/21/2022] Open
Abstract
MicroRNAs (miRNAs) are small non-coding molecules that regulate a large amount of post-transcriptional repressor genes by recognizing semi-complementary target sequences that are normally located in the 3' UTR of the mRNA. Altered expression of miRNA has been related to several pathological processes, including polyglutamine (Poly Q) diseases. Specific expression patterns in the circulating fluids and brain parenchyma have been speculated as potential biomarkers for Poly Q disease diagnosis and prognosis. Several miRNAs have been consistently identified in diseases including Huntington's disease (HD) and spinocerebellar ataxia (SCA). In our review, we describe the emerging role of miRNAs in Poly Q diseases and provide an overview on general miRNA biology, implications in pathophysiology, and their potential roles as future biomarkers and applications for therapy.
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Affiliation(s)
| | - Shuyan Cong
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, China
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16
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Sharma M, Subramaniam S. Rhes travels from cell to cell and transports Huntington disease protein via TNT-like protrusion. J Cell Biol 2019; 218:1972-1993. [PMID: 31076452 PMCID: PMC6548131 DOI: 10.1083/jcb.201807068] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/17/2018] [Accepted: 04/08/2019] [Indexed: 02/07/2023] Open
Abstract
Tunneling nanotubes (TNT) are membranous tubes that connect two cells, but their functional roles and mechanism of biogenesis remain obscure. Sharma and Subramaniam demonstrate that Rhes, a brain-enriched protein, increases biogenesis of TNT-like cellular protrusions or “Rhes tunnels” through which Rhes travels from cell to cell and transports Huntington disease (HD) protein. Tunneling nanotubes (TNT) are thin, membranous, tunnel-like cell-to-cell connections, but the mechanisms underlying their biogenesis or functional role remains obscure. Here, we report, Rhes, a brain-enriched GTPase/SUMO E3-like protein, induces the biogenesis of TNT-like cellular protrusions, “Rhes tunnels,” through which Rhes moves from cell to cell and transports Huntington disease (HD) protein, the poly-Q expanded mutant Huntingtin (mHTT). The formation of TNT-like Rhes tunnels requires the Rhes’s serine 33, C-terminal CAAX, and a SUMO E3-like domain. Electron microscopy analysis revealed that TNT-like Rhes tunnels appear continuous, cell–cell connections, and <200 nm in diameter. Live-cell imaging shows that Rhes tunnels establish contact with the neighboring cell and deliver Rhes-positive cargoes, which travel across the plasma membrane of the neighboring cell before entering it. The Rhes tunnels carry Rab5a/Lyso 20-positive vesicles and transport mHTT, but not normal HTT, mTOR, or wtTau proteins. SUMOylation-defective mHTT, Rhes C263S (cannot SUMOylate mHTT), or CRISPR/Cas9-mediated depletion of three isoforms of SUMO diminishes Rhes-mediated mHTT transport. Thus, Rhes promotes the biogenesis of TNT-like cellular protrusions and facilitates the cell–cell transport of mHTT involving SUMO-mediated mechanisms.
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Affiliation(s)
- Manish Sharma
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL
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17
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Hernandez I, Luna G, Rauch JN, Reis SA, Giroux M, Karch CM, Boctor D, Sibih YE, Storm NJ, Diaz A, Kaushik S, Zekanowski C, Kang AA, Hinman CR, Cerovac V, Guzman E, Zhou H, Haggarty SJ, Goate AM, Fisher SK, Cuervo AM, Kosik KS. A farnesyltransferase inhibitor activates lysosomes and reduces tau pathology in mice with tauopathy. Sci Transl Med 2019; 11:eaat3005. [PMID: 30918111 PMCID: PMC7961212 DOI: 10.1126/scitranslmed.aat3005] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 08/15/2018] [Accepted: 11/30/2018] [Indexed: 11/02/2022]
Abstract
Tau inclusions are a shared feature of many neurodegenerative diseases, among them frontotemporal dementia caused by tau mutations. Treatment approaches for these conditions include targeting posttranslational modifications of tau proteins, maintaining a steady-state amount of tau, and preventing its tendency to aggregate. We discovered a new regulatory pathway for tau degradation that operates through the farnesylated protein, Rhes, a GTPase in the Ras family. Here, we show that treatment with the farnesyltransferase inhibitor lonafarnib reduced Rhes and decreased brain atrophy, tau inclusions, tau sumoylation, and tau ubiquitination in the rTg4510 mouse model of tauopathy. In addition, lonafarnib treatment attenuated behavioral abnormalities in rTg4510 mice and reduced microgliosis in mouse brain. Direct reduction of Rhes in the rTg4510 mouse by siRNA reproduced the results observed with lonafarnib treatment. The mechanism of lonafarnib action mediated by Rhes to reduce tau pathology was shown to operate through activation of lysosomes. We finally showed in mouse brain and in human induced pluripotent stem cell-derived neurons a normal developmental increase in Rhes that was initially suppressed by tau mutations. The known safety of lonafarnib revealed in human clinical trials for cancer suggests that this drug could be repurposed for treating tauopathies.
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Affiliation(s)
- Israel Hernandez
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Gabriel Luna
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Jennifer N Rauch
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Surya A Reis
- Department of Neurology, Massachusetts General Hospital, Chemical Neurobiology Lab, and Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Michel Giroux
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Celeste M Karch
- Department of Psychiatry, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Daniel Boctor
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Youssef E Sibih
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Nadia J Storm
- Department of Developmental and Molecular Biology and Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Antonio Diaz
- Department of Developmental and Molecular Biology and Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Susmita Kaushik
- Department of Developmental and Molecular Biology and Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Cezary Zekanowski
- Laboratory of Neurogenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106 Warsaw, Poland
| | - Alexander A Kang
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Cassidy R Hinman
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Vesna Cerovac
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Elmer Guzman
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Honjun Zhou
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Stephen J Haggarty
- Department of Neurology, Massachusetts General Hospital, Chemical Neurobiology Lab, and Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Alison M Goate
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Steven K Fisher
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Ana M Cuervo
- Department of Developmental and Molecular Biology and Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Kenneth S Kosik
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
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18
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Tambasco N, Romoli M, Calabresi P. Selective basal ganglia vulnerability to energy deprivation: Experimental and clinical evidences. Prog Neurobiol 2018; 169:55-75. [DOI: 10.1016/j.pneurobio.2018.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 07/24/2018] [Accepted: 07/27/2018] [Indexed: 02/07/2023]
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19
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Alqinyah M, Hooks SB. Regulating the regulators: Epigenetic, transcriptional, and post-translational regulation of RGS proteins. Cell Signal 2017; 42:77-87. [PMID: 29042285 DOI: 10.1016/j.cellsig.2017.10.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/06/2017] [Accepted: 10/13/2017] [Indexed: 12/11/2022]
Abstract
Regulators of G protein signaling (RGS) are a family of proteins classically known to accelerate the intrinsic GTPase activity of G proteins, which results in accelerated inactivation of heterotrimeric G proteins and inhibition of G protein coupled receptor signaling. RGS proteins play major roles in essential cellular processes, and dysregulation of RGS protein expression is implicated in multiple diseases, including cancer, cardiovascular and neurodegenerative diseases. The expression of RGS proteins is highly dynamic and is regulated by epigenetic, transcriptional and post-translational mechanisms. This review summarizes studies that report dysregulation of RGS protein expression in disease states, and presents examples of drugs that regulate RGS protein expression. Additionally, this review discusses, in detail, the transcriptional and post-transcriptional mechanisms regulating RGS protein expression, and further assesses the therapeutic potential of targeting these mechanisms. Understanding the molecular mechanisms controlling the expression of RGS proteins is essential for the development of therapeutics that indirectly modulate G protein signaling by regulating expression of RGS proteins.
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Affiliation(s)
- Mohammed Alqinyah
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA
| | - Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA.
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20
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Raab A, Popp S, Lesch KP, Lohse MJ, Fischer M, Deckert J, Hommers L. Increased fear learning, spatial learning as well as neophobia in Rgs2−/−
mice. GENES BRAIN AND BEHAVIOR 2017; 17:e12420. [DOI: 10.1111/gbb.12420] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/20/2017] [Accepted: 08/22/2017] [Indexed: 12/13/2022]
Affiliation(s)
- A. Raab
- Interdisciplinary Center for Clinical Research; University Hospital of Würzburg; Würzburg Germany
- Comprehensive Hearth Failure Center (CHFC); University Hospital of Würzburg; Würzburg Germany
- Institute of Pharmacology and Toxicology; University of Würzburg; Würzburg Germany
| | - S. Popp
- Division of Molecular Psychiatry, Center for Mental Health; University Hospital of Würzburg; Würzburg Germany
| | - K.-P. Lesch
- Comprehensive Hearth Failure Center (CHFC); University Hospital of Würzburg; Würzburg Germany
- Division of Molecular Psychiatry, Center for Mental Health; University Hospital of Würzburg; Würzburg Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine; I.M. Sechenov First Moscow State Medical University; Moscow Russia
- Department of Translational Neuroscience, School of Mental Health and Neuroscience; Maastricht University; Maastricht The Netherlands
| | - M. J. Lohse
- Comprehensive Hearth Failure Center (CHFC); University Hospital of Würzburg; Würzburg Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association; Berlin Germany
| | - M. Fischer
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center for Mental Health; University Hospital of Würzburg; Würzburg Germany
| | - J. Deckert
- Comprehensive Hearth Failure Center (CHFC); University Hospital of Würzburg; Würzburg Germany
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center for Mental Health; University Hospital of Würzburg; Würzburg Germany
| | - L. Hommers
- Interdisciplinary Center for Clinical Research; University Hospital of Würzburg; Würzburg Germany
- Comprehensive Hearth Failure Center (CHFC); University Hospital of Würzburg; Würzburg Germany
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center for Mental Health; University Hospital of Würzburg; Würzburg Germany
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21
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Decreased Rhes mRNA levels in the brain of patients with Parkinson's disease and MPTP-treated macaques. PLoS One 2017; 12:e0181677. [PMID: 28742811 PMCID: PMC5526584 DOI: 10.1371/journal.pone.0181677] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/05/2017] [Indexed: 01/06/2023] Open
Abstract
In rodent and human brains, the small GTP-binding protein Rhes is highly expressed in virtually all dopaminoceptive striatal GABAergic medium spiny neurons, as well as in large aspiny cholinergic interneurons, where it is thought to modulate dopamine-dependent signaling. Consistent with this knowledge, and considering that dopaminergic neurotransmission is altered in neurological and psychiatric disorders, here we sought to investigate whether Rhes mRNA expression is altered in brain regions of patients with Parkinson’s disease (PD), Schizophrenia (SCZ), and Bipolar Disorder (BD), when compared to healthy controls (about 200 post-mortem samples). Moreover, we performed the same analysis in the putamen of non-human primate Macaca Mulatta, lesioned with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Overall, our data indicated comparable Rhes mRNA levels in the brain of patients with SCZ and BD, and their respective healthy controls. In sharp contrast, the putamen of patients suffering from PD showed a significant 35% reduction of this transcript, compared to healthy subjects. Interestingly, in line with observations obtained in humans, we found 27% decrease in Rhes mRNA levels in the putamen of MPTP-treated primates. Based on the established inhibitory influence of Rhes on dopamine-related responses, we hypothesize that its striatal downregulation in PD patients and animal models of PD might represent an adaptive event of the dopaminergic system to functionally counteract the reduced nigrostriatal innervation.
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22
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Shahani N, Swarnkar S, Giovinazzo V, Morgenweck J, Bohn LM, Scharager-Tapia C, Pascal B, Martinez-Acedo P, Khare K, Subramaniam S. RasGRP1 promotes amphetamine-induced motor behavior through a Rhes interaction network ("Rhesactome") in the striatum. Sci Signal 2016; 9:ra111. [PMID: 27902448 PMCID: PMC5142824 DOI: 10.1126/scisignal.aaf6670] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The striatum of the brain coordinates motor function. Dopamine-related drugs may be therapeutic to patients with striatal neurodegeneration, such as Huntington's disease (HD) and Parkinson's disease (PD), but these drugs have unwanted side effects. In addition to stimulating the release of norepinephrine, amphetamines, which are used for narcolepsy and attention-deficit/hyperactivity disorder (ADHD), trigger dopamine release in the striatum. The guanosine triphosphatase Ras homolog enriched in the striatum (Rhes) inhibits dopaminergic signaling in the striatum, is implicated in HD and L-dopa-induced dyskinesia, and has a role in striatal motor control. We found that the guanine nucleotide exchange factor RasGRP1 inhibited Rhes-mediated control of striatal motor activity in mice. RasGRP1 stabilized Rhes, increasing its synaptic accumulation in the striatum. Whereas partially Rhes-deficient (Rhes+/-) mice had an enhanced locomotor response to amphetamine, this phenotype was attenuated by coincident depletion of RasGRP1. By proteomic analysis of striatal lysates from Rhes-heterozygous mice with wild-type or partial or complete knockout of Rasgrp1, we identified a diverse set of Rhes-interacting proteins, the "Rhesactome," and determined that RasGRP1 affected the composition of the amphetamine-induced Rhesactome, which included PDE2A (phosphodiesterase 2A; a protein associated with major depressive disorder), LRRC7 (leucine-rich repeat-containing 7; a protein associated with bipolar disorder and ADHD), and DLG2 (discs large homolog 2; a protein associated with chronic pain). Thus, this Rhes network provides insight into striatal effects of amphetamine and may aid the development of strategies to treat various neurological and psychological disorders associated with the striatal dysfunction.
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Affiliation(s)
- Neelam Shahani
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Supriya Swarnkar
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Vincenzo Giovinazzo
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Jenny Morgenweck
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Laura M Bohn
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | | | - Bruce Pascal
- Informatics Core, The Scripps Research Institute, Jupiter, FL 33458, USA
| | | | - Kshitij Khare
- Department of Statistics, University of Florida, Gainesville, FL 32611, USA
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23
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Hadar A, Milanesi E, Squassina A, Niola P, Chillotti C, Pasmanik-Chor M, Yaron O, Martásek P, Rehavi M, Weissglas-Volkov D, Shomron N, Gozes I, Gurwitz D. RGS2 expression predicts amyloid-β sensitivity, MCI and Alzheimer's disease: genome-wide transcriptomic profiling and bioinformatics data mining. Transl Psychiatry 2016; 6:e909. [PMID: 27701409 PMCID: PMC5315547 DOI: 10.1038/tp.2016.179] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 05/26/2016] [Accepted: 06/15/2016] [Indexed: 12/30/2022] Open
Abstract
Alzheimer's disease (AD) is the most frequent cause of dementia. Misfolded protein pathological hallmarks of AD are brain deposits of amyloid-β (Aβ) plaques and phosphorylated tau neurofibrillary tangles. However, doubts about the role of Aβ in AD pathology have been raised as Aβ is a common component of extracellular brain deposits found, also by in vivo imaging, in non-demented aged individuals. It has been suggested that some individuals are more prone to Aβ neurotoxicity and hence more likely to develop AD when aging brains start accumulating Aβ plaques. Here, we applied genome-wide transcriptomic profiling of lymphoblastoid cells lines (LCLs) from healthy individuals and AD patients for identifying genes that predict sensitivity to Aβ. Real-time PCR validation identified 3.78-fold lower expression of RGS2 (regulator of G-protein signaling 2; P=0.0085) in LCLs from healthy individuals exhibiting high vs low Aβ sensitivity. Furthermore, RGS2 showed 3.3-fold lower expression (P=0.0008) in AD LCLs compared with controls. Notably, RGS2 expression in AD LCLs correlated with the patients' cognitive function. Lower RGS2 expression levels were also discovered in published expression data sets from postmortem AD brain tissues as well as in mild cognitive impairment and AD blood samples compared with controls. In conclusion, Aβ sensitivity phenotyping followed by transcriptomic profiling and published patient data mining identified reduced peripheral and brain expression levels of RGS2, a key regulator of G-protein-coupled receptor signaling and neuronal plasticity. RGS2 is suggested as a novel AD biomarker (alongside other genes) toward early AD detection and future disease modifying therapeutics.
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Affiliation(s)
- A Hadar
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - E Milanesi
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - A Squassina
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - P Niola
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - C Chillotti
- Unit of Clinical Pharmacology, University Hospital of Cagliari, Cagliari, Italy
| | - M Pasmanik-Chor
- Bioinformatics Unit, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - O Yaron
- The Genomic Analysis Laboratory, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - P Martásek
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - M Rehavi
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - D Weissglas-Volkov
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - N Shomron
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel,Adams Super Center for Brain Studies, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - I Gozes
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel,Adams Super Center for Brain Studies, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel,Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel. E-mail: or
| | - D Gurwitz
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel,Adams Super Center for Brain Studies, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel,Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel. E-mail: or
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24
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Crittenden J, Graybiel A. Disease-Associated Changes in the Striosome and Matrix Compartments of the Dorsal Striatum. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2016. [DOI: 10.1016/b978-0-12-802206-1.00039-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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25
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Swarnkar S, Chen Y, Pryor WM, Shahani N, Page DT, Subramaniam S. Ectopic expression of the striatal-enriched GTPase Rhes elicits cerebellar degeneration and an ataxia phenotype in Huntington's disease. Neurobiol Dis 2015; 82:66-77. [PMID: 26048156 DOI: 10.1016/j.nbd.2015.05.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 04/02/2015] [Accepted: 05/26/2015] [Indexed: 12/31/2022] Open
Abstract
Huntington's disease (HD) is caused by an expansion of glutamine repeats in the huntingtin protein (mHtt) that invokes early and prominent damage of the striatum, a region that controls motor behaviors. Despite its ubiquitous expression, why certain brain regions, such as the cerebellum, are relatively spared from neuronal loss by mHtt remains unclear. Previously, we implicated the striatal-enriched GTPase, Rhes (Ras homolog enriched in the striatum), which binds and SUMOylates mHtt and increases its solubility and cellular cytotoxicity, as the cause for striatal toxicity in HD. Here, we report that Rhes deletion in HD mice (N171-82Q), which express the N-terminal fragment of human Htt with 82 glutamines (Rhes(-/-)/N171-82Q), display markedly reduced HD-related behavioral deficits, and absence of lateral ventricle dilatation (secondary to striatal atrophy), compared to control HD mice (N171-82Q). To further validate the role of GTPase Rhes in HD, we tested whether ectopic Rhes expression would elicit a pathology in a brain region normally less affected in HD. Remarkably, ectopic expression of Rhes in the cerebellum of N171-82Q mice, during the asymptomatic period led to an exacerbation of motor deficits, including loss of balance and motor incoordination with ataxia-like features, not apparent in control-injected N171-82Q mice or Rhes injected wild-type mice. Pathological and biochemical analysis of Rhes-injected N171-82Q mice revealed a cerebellar lesion with marked loss of Purkinje neuron layer parvalbumin-immunoreactivity, induction of caspase 3 activation, and enhanced soluble forms of mHtt. Similarly reintroducing Rhes into the striatum of Rhes deleted Rhes(-/-)Hdh(150Q/150Q) knock-in mice, elicited a progressive HD-associated rotarod deficit. Overall, these studies establish that Rhes plays a pivotal role in vivo for the selective toxicity of mHtt in HD.
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Affiliation(s)
- Supriya Swarnkar
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Youjun Chen
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - William M Pryor
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Neelam Shahani
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Damon T Page
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Srinivasa Subramaniam
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA.
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26
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Cortes CJ, La Spada AR. Autophagy in polyglutamine disease: Imposing order on disorder or contributing to the chaos? Mol Cell Neurosci 2015; 66:53-61. [PMID: 25771431 DOI: 10.1016/j.mcn.2015.03.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 03/07/2015] [Accepted: 03/09/2015] [Indexed: 12/13/2022] Open
Abstract
Autophagy is an essential, fundamentally important catabolic pathway in which double membrane-bound vesicles form in the cytosol and encircle macromolecules and organelles to permit their degradation after fusion with lysosomes. More than a decade of research has revealed that autophagy is required for normal central nervous system (CNS) function and plays a central role in maintaining protein and organelle quality controls in neurons. Neurodegenerative diseases occur when misfolded proteins accumulate and disrupt normal cellular processes, and autophagy has emerged as a key arbiter of the cell's homeostatic response to this threat. One class of inherited neurodegenerative disease is known as the CAG/polyglutamine repeat disorders, and these diseases all result from the expansion of a CAG repeat tract in the coding regions of distinct genes. Polyglutamine (polyQ) repeat diseases result in the production polyQ-expanded proteins that misfold to form inclusions or aggregates that challenge the main cellular proteostasis system of the cell, the ubiquitin proteasome system (UPS). The UPS cannot efficiently degrade polyQ-expanded disease proteins, and components of the UPS are enriched in polyQ disease aggregate bodies found in degenerating neurons. In addition to components of the UPS, polyQ protein cytosolic aggregates co-localize with key autophagy proteins, even in autophagy deficient cells, suggesting that they probably do not reflect the formation of autophagosomes but rather the sequestration of key autophagy components. Furthermore, recent evidence now implicates polyQ proteins in the regulation of the autophagy pathway itself. Thus, a complex model emerges where polyQ proteins play a dual role as both autophagy substrates and autophagy offenders. In this review, we consider the role of autophagy in polyQ disorders and the therapeutic potential for autophagy modulation in these diseases. This article is part of a Special Issue entitled "Neuronal Protein".
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Affiliation(s)
- Constanza J Cortes
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Albert R La Spada
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92037, USA; Department of Cellular & Molecular Medicine, University of California, San Diego, La Jolla, CA 92037, USA; Department of Neurosciences, University of California, San Diego, La Jolla, CA 92037, USA; Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92037, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92037, USA; Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037, USA; Rady Children's Hospital, San Diego, CA 92193, USA.
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27
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Kreiner G. Compensatory mechanisms in genetic models of neurodegeneration: are the mice better than humans? Front Cell Neurosci 2015; 9:56. [PMID: 25798086 PMCID: PMC4351629 DOI: 10.3389/fncel.2015.00056] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 02/06/2015] [Indexed: 01/08/2023] Open
Abstract
Neurodegenerative diseases are one of the main causes of mental and physical disabilities. Neurodegeneration has been estimated to begin many years before the first clinical symptoms manifest, and even a prompt diagnosis at this stage provides very little advantage for a more effective treatment as the currently available pharmacotherapies are based on disease symptomatology. The etiology of the majority of neurodegenerative diseases remains unknown, and even for those diseases caused by identified genetic mutations, the direct pathways from gene alteration to final cell death have not yet been fully elucidated. Advancements in genetic engineering have provided many transgenic mice that are used as an alternative to pharmacological models of neurodegenerative diseases. Surprisingly, even the models reiterating the same causative mutations do not fully recapitulate the inevitable neuronal loss, and some fail to even show phenotypic alterations, which suggests the possible existence of compensatory mechanisms. A better evaluation of these mechanisms may not only help us to explain why neurodegenerative diseases are mostly late-onset disorders in humans but may also provide new markers and targets for novel strategies designed to extend neuronal function and survival. The aim of this mini-review is to draw attention to this under-explored field in which investigations may reasonably contribute to unveiling hidden reserves in the organism.
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Affiliation(s)
- Grzegorz Kreiner
- Department of Brain Biochemistry, Institute of Pharmacology, Polish Academy of Sciences Kraków, Poland
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28
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Reinstating aberrant mTORC1 activity in Huntington's disease mice improves disease phenotypes. Neuron 2014; 85:303-15. [PMID: 25556834 DOI: 10.1016/j.neuron.2014.12.019] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2014] [Indexed: 12/28/2022]
Abstract
Huntington's disease (HD) is caused by a polyglutamine tract expansion in huntingtin (HTT). Despite HTTs ubiquitous expression, there is early and robust vulnerability in striatum, the cause of which is poorly understood. Here, we provide evidence that impaired striatal mTORC1 activity underlies varied metabolic and degenerative phenotypes in HD brain and show that introducing the constitutively active form of the mTORC1 regulator, Rheb, into HD mouse brain, alleviates mitochondrial dysfunction, aberrant cholesterol homeostasis, striatal atrophy, impaired dopamine signaling, and increases autophagy. We also find that the expression of Rhes, a striatum-enriched mTOR activator, is reduced in HD patient and mouse brain and that exogenous addition of Rhes alleviates motor deficits and improves brain pathology in HD mice. Our combined work indicates that impaired Rhes/mTORC1 activity in HD brain may underlie the notable striatal susceptibility and thus presents a promising therapeutic target for HD therapy.
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Striatal long noncoding RNA Abhd11os is neuroprotective against an N-terminal fragment of mutant huntingtin in vivo. Neurobiol Aging 2014; 36:1601.e7-16. [PMID: 25619660 DOI: 10.1016/j.neurobiolaging.2014.11.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/28/2014] [Accepted: 11/25/2014] [Indexed: 12/26/2022]
Abstract
A large number of gene products that are enriched in the striatum have ill-defined functions, although they may have key roles in age-dependent neurodegenerative diseases affecting the striatum, especially Huntington disease (HD). In the present study, we focused on Abhd11os, (called ABHD11-AS1 in human) which is a putative long noncoding RNA (lncRNA) whose expression is enriched in the mouse striatum. We confirm that despite the presence of 2 small open reading frames (ORFs) in its sequence, Abhd11os is not translated into a detectable peptide in living cells. We demonstrate that Abhd11os levels are markedly reduced in different mouse models of HD. We performed in vivo experiments in mice using lentiviral vectors encoding either Abhd11os or a small hairpin RNA targeting Abhd11os. Results show that Abhd11os overexpression produces neuroprotection against an N-terminal fragment of mutant huntingtin, whereas Abhd11os knockdown is protoxic. These novel results indicate that the loss lncRNA Abhd11os likely contribute to striatal vulnerability in HD. Our study emphasizes that lncRNA may play crucial roles in neurodegenerative diseases.
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30
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Francelle L, Galvan L, Gaillard MC, Guillermier M, Houitte D, Bonvento G, Petit F, Jan C, Dufour N, Hantraye P, Elalouf JM, De Chaldée M, Déglon N, Brouillet E. Loss of the thyroid hormone-binding protein Crym renders striatal neurons more vulnerable to mutant huntingtin in Huntington's disease. Hum Mol Genet 2014; 24:1563-73. [PMID: 25398949 PMCID: PMC4381754 DOI: 10.1093/hmg/ddu571] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The mechanisms underlying preferential atrophy of the striatum in Huntington's disease (HD) are unknown. One hypothesis is that a set of gene products preferentially expressed in the striatum could determine the particular vulnerability of this brain region to mutant huntingtin (mHtt). Here, we studied the striatal protein µ-crystallin (Crym). Crym is the NADPH-dependent p38 cytosolic T3-binding protein (p38CTBP), a key regulator of thyroid hormone (TH) T3 (3,5,3'-triiodo-l-thyronine) transportation. It has been also recently identified as the enzyme that reduces the sulfur-containing cyclic ketimines, which are potential neurotransmitters. Here, we confirm the preferential expression of the Crym protein in the rodent and macaque striatum. Crym expression was found to be higher in the macaque caudate than in the putamen. Expression of Crym was reduced in the BACHD and Knock-in 140CAG mouse models of HD before onset of striatal atrophy. We show that overexpression of Crym in striatal medium-size spiny neurons using a lentiviral-based strategy in mice is neuroprotective against the neurotoxicity of an N-terminal fragment of mHtt in vivo. Thus, reduction of Crym expression in HD could render striatal neurons more susceptible to mHtt suggesting that Crym may be a key determinant of the vulnerability of the striatum. In addition our work points to Crym as a potential molecular link between striatal degeneration and the THs deregulation reported in HD patients.
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Affiliation(s)
- Laetitia Francelle
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Laurie Galvan
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Marie-Claude Gaillard
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Martine Guillermier
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Diane Houitte
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Gilles Bonvento
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Fanny Petit
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Caroline Jan
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Noëlle Dufour
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Philippe Hantraye
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Jean-Marc Elalouf
- CEA, iBiTecS, F-91191 Gif-sur-Yvette Cedex, France, CNRS, FRE 3377, F-91191 Gif-sur-Yvette Cedex, France, Université Paris-Sud, FRE 3377, F-91191 Gif-sur-Yvette Cedex, France
| | - Michel De Chaldée
- CEA, iBiTecS, F-91191 Gif-sur-Yvette Cedex, France, CNRS, FRE 3377, F-91191 Gif-sur-Yvette Cedex, France, Université Paris-Sud, FRE 3377, F-91191 Gif-sur-Yvette Cedex, France
| | - Nicole Déglon
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France, Laboratory of Cellular and Molecular Neurotherapies, Department of Clinical Neurociences, Lausanne University Hospital, Lausanne, Switzerland
| | - Emmanuel Brouillet
- CEA, DSV, I²BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France, Neurodegenerative Diseases Laboratory, CNRS CEA URA 2210, F-92265 Fontenay-aux-Roses, France,
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31
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Pryor WM, Biagioli M, Shahani N, Swarnkar S, Huang WC, Page DT, MacDonald ME, Subramaniam S. Huntingtin promotes mTORC1 signaling in the pathogenesis of Huntington's disease. Sci Signal 2014; 7:ra103. [DOI: 10.1126/scisignal.2005633] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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32
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Lee JH, Sowada MJ, Boudreau RL, Aerts AM, Thedens DR, Nopoulos P, Davidson BL. Rhes suppression enhances disease phenotypes in Huntington's disease mice. J Huntingtons Dis 2014; 3:65-71. [PMID: 25062765 DOI: 10.3233/jhd-140094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In Huntington's disease (HD) mutant HTT is ubiquitously expressed yet the striatum undergoes profound early degeneration. Cell culture studies suggest that a striatal-enriched protein, Rhes, may account for this vulnerability. We investigated the therapeutic potential of silencing Rhes in vivo using inhibitory RNAs (miRhes). While Rhes suppression was tolerated in wildtype mice, it failed to improve rotarod function in two distinct HD mouse models. Additionally, miRhes treated HD mice had increased anxiety-like behaviors and enhanced striatal atrophy as measured by longitudinal MRI when compared to control treated mice. These findings raise caution regarding the long-term implementation of inhibiting Rhes as a therapy for HD.
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Affiliation(s)
- John H Lee
- Medical Scientist Training Program, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA Department of Molecular Physiology & Biophysics, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - Matthew J Sowada
- Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - Ryan L Boudreau
- Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - Andrea M Aerts
- Department of Psychiatry, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - Daniel R Thedens
- Department of Radiology, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - Peg Nopoulos
- Department of Psychiatry, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
| | - Beverly L Davidson
- Department of Molecular Physiology & Biophysics, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA Department of Neurology, Roy J and Lucille A Carver College of Medicine, Iowa City, IA, USA
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33
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Francelle L, Galvan L, Brouillet E. Possible involvement of self-defense mechanisms in the preferential vulnerability of the striatum in Huntington's disease. Front Cell Neurosci 2014; 8:295. [PMID: 25309327 PMCID: PMC4176035 DOI: 10.3389/fncel.2014.00295] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 09/03/2014] [Indexed: 01/01/2023] Open
Abstract
HD is caused by a mutation in the huntingtin gene that consists in a CAG repeat expansion translated into an abnormal poly-glutamine (polyQ) tract in the huntingtin (Htt) protein. The most striking neuropathological finding in HD is the atrophy of the striatum. The regional expression of mutant Htt (mHtt) is ubiquitous in the brain and cannot explain by itself the preferential vulnerability of the striatum in HD. mHtt has been shown to produce an early defect in transcription, through direct alteration of the function of key regulators of transcription and in addition, more indirectly, as a result of compensatory responses to cellular stress. In this review, we focus on gene products that are preferentially expressed in the striatum and have down- or up-regulated expression in HD and, as such, may play a crucial role in the susceptibility of the striatum to mHtt. Many of these striatal gene products are for a vast majority down-regulated and more rarely increased in HD. Recent research shows that some of these striatal markers have a pro-survival/neuroprotective role in neurons (e.g., MSK1, A2A, and CB1 receptors) whereas others enhance the susceptibility of striatal neurons to mHtt (e.g., Rhes, RGS2, D2 receptors). The down-regulation of these latter proteins may be considered as a potential self-defense mechanism to slow degeneration. For a majority of the striatal gene products that have been identified so far, their function in the striatum is unknown and their modifying effects on mHtt toxicity remain to be experimentally addressed. Focusing on these striatal markers may contribute to a better understanding of HD pathogenesis, and possibly the identification of novel therapeutic targets.
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Affiliation(s)
- Laetitia Francelle
- Neurodegenerative Disease Laboratory, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Direction des Sciences du Vivant, Institut d'Imagerie BioMédicale, Molecular Imaging Research Center Fontenay-aux-Roses, France ; Centre National de la Recherche Scientifique - Commissariat à l'Énergie Atomique et aux Énergies Alternatives Unité de Recherche Associée 2210 Fontenay-aux-Roses, France
| | - Laurie Galvan
- Neurodegenerative Disease Laboratory, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Direction des Sciences du Vivant, Institut d'Imagerie BioMédicale, Molecular Imaging Research Center Fontenay-aux-Roses, France ; Centre National de la Recherche Scientifique - Commissariat à l'Énergie Atomique et aux Énergies Alternatives Unité de Recherche Associée 2210 Fontenay-aux-Roses, France ; Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, David Geffen School of Medicine, University of California Los Angeles Los Angeles, CA, USA
| | - Emmanuel Brouillet
- Neurodegenerative Disease Laboratory, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Direction des Sciences du Vivant, Institut d'Imagerie BioMédicale, Molecular Imaging Research Center Fontenay-aux-Roses, France ; Centre National de la Recherche Scientifique - Commissariat à l'Énergie Atomique et aux Énergies Alternatives Unité de Recherche Associée 2210 Fontenay-aux-Roses, France
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34
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Wang C, Ji B, Cheng B, Chen J, Bai B. Neuroprotection of microRNA in neurological disorders (Review). Biomed Rep 2014; 2:611-619. [PMID: 25053999 DOI: 10.3892/br.2014.297] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/13/2014] [Indexed: 02/07/2023] Open
Abstract
MicroRNAs (miRNAs) are small, endogenous, non-coding RNA molecules that function as post-transcriptional regulators of gene expression by imperfect base-pairing with the 3'-untranslated regions of their target mRNAs. Altered expression of numerous miRNAs has been shown to be extensively involved in the pathogenesis of various diseases and cancers. Additionally, the specific expression of miRNAs in the nervous system has indicated that miRNAs are critical for the occurrence and development of neurological diseases. Increasing evidence has shown that specific miRNAs target the expression of particular proteins that are significant in the disease pathogenesis. Therefore, miRNA-mediated regulation may be important in the occurrence and development of neurological diseases and may function as a novel biomarker and tool for clinical therapy. In the present study, the significance of miRNAs is reviewed in a number of neurological disorders and the possibility of their use in therapeutic interventions is evaluated.
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Affiliation(s)
- Chunmei Wang
- Neurobiology Institute, Jining Medical University, Jining 272067, P.R. China
| | - Bingyuan Ji
- Neurobiology Institute, Jining Medical University, Jining 272067, P.R. China ; School of Life Science, Shandong Agricultural University, Taian 271018, P.R. China
| | - Baohua Cheng
- Neurobiology Institute, Jining Medical University, Jining 272067, P.R. China
| | - Jing Chen
- Neurobiology Institute, Jining Medical University, Jining 272067, P.R. China
| | - Bo Bai
- Neurobiology Institute, Jining Medical University, Jining 272067, P.R. China
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35
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Muller M, Leavitt BR. Iron dysregulation in Huntington's disease. J Neurochem 2014; 130:328-50. [PMID: 24717009 DOI: 10.1111/jnc.12739] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/19/2014] [Accepted: 04/07/2014] [Indexed: 12/13/2022]
Abstract
Huntington's disease (HD) is one of many neurodegenerative diseases with reported alterations in brain iron homeostasis that may contribute to neuropathogenesis. Iron accumulation in the specific brain areas of neurodegeneration in HD has been proposed based on observations in post-mortem tissue and magnetic resonance imaging studies. Altered magnetic resonance imaging signal within specific brain regions undergoing neurodegeneration has been consistently reported and interpreted as altered levels of brain iron. Biochemical studies using various techniques to measure iron species in human samples, mouse tissue, or in vitro has generated equivocal data to support such an association. Whether elevated brain iron occurs in HD, plays a significant contributing role in HD pathogenesis, or is a secondary effect remains currently unclear.
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Affiliation(s)
- Michelle Muller
- Department of Medical Genetics, Centre for Molecular Medicine & Therapeutics, University of British Columbia and Children's and Women's Hospital, Vancouver, British Columbia, Canada
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36
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Mealer RG, Murray AJ, Shahani N, Subramaniam S, Snyder SH. Rhes, a striatal-selective protein implicated in Huntington disease, binds beclin-1 and activates autophagy. J Biol Chem 2013; 289:3547-54. [PMID: 24324270 DOI: 10.1074/jbc.m113.536912] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The protein mutated in Huntington disease (HD), mutant huntingtin (mHtt), is expressed throughout the brain and body. However, the pathology of HD is characterized by early and dramatic destruction selectively of the striatum. We previously reported that the striatal-specific protein Rhes binds mHtt and enhances its cytotoxicity. Moreover, Rhes-deleted mice are dramatically protected from neurodegeneration and motor dysfunction in mouse models of HD. We now report a function of Rhes in autophagy, a lysosomal degradation pathway implicated in aging and HD neurodegeneration. In PC12 cells, deletion of endogenous Rhes decreases autophagy, whereas Rhes overexpression activates autophagy. These effects are independent of mTOR and opposite in the direction predicted by the known activation of mTOR by Rhes. Rhes robustly binds the autophagy regulator Beclin-1, decreasing its inhibitory interaction with Bcl-2 independent of JNK-1 signaling. Finally, co-expression of mHtt blocks Rhes-induced autophagy activation. Thus, the isolated pathology and delayed onset of HD may reflect the striatal-selective expression and changes in autophagic activity of Rhes.
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37
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Hutson TH, Foster E, Moon LDF, Yáñez-Muñoz RJ. Lentiviral vector-mediated RNA silencing in the central nervous system. Hum Gene Ther Methods 2013; 25:14-32. [PMID: 24090197 DOI: 10.1089/hgtb.2013.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
RNA silencing is an established method for investigating gene function and has attracted particular interest because of the potential for generating RNA-based therapeutics. Using lentiviral vectors as an efficient delivery system that offers stable, long-term expression in postmitotic cells further enhances the applicability of an RNA-based gene therapy for the CNS. In this review we provide an overview of both lentiviral vectors and RNA silencing along with design considerations for generating lentiviral vectors capable of RNA silencing. We go on to describe the current preclinical data regarding lentiviral vector-mediated RNA silencing for CNS disorders and discuss the concerns of side effects associated with lentiviral vectors and small interfering RNAs and how these might be mitigated.
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Affiliation(s)
- Thomas H Hutson
- 1 Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London , Guy's Campus, London SE1 1UL, United Kingdom
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38
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Sbodio JI, Paul BD, Machamer CE, Snyder SH. Golgi protein ACBD3 mediates neurotoxicity associated with Huntington's disease. Cell Rep 2013; 4:890-7. [PMID: 24012756 PMCID: PMC3801179 DOI: 10.1016/j.celrep.2013.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/02/2013] [Accepted: 08/01/2013] [Indexed: 01/10/2023] Open
Abstract
Huntington's disease (HD) is an autosomal-dominant neurodegenerative disease caused by the expansion of polyglutamine repeats in the gene for huntingtin (Htt). In HD, the corpus striatum selectively degenerates despite the uniform expression of mutant huntingtin (mHtt) throughout the brain and body. Striatal selectivity reflects the binding of the striatal-selective protein Rhes to mHtt to augment cytotoxicity, but molecular mechanisms underlying the toxicity have been elusive. Here, we report that the Golgi protein acyl-CoA binding domain containing 3 (ACBD3) mediates mHtt cytotoxicity via a Rhes/mHtt/ACBD3 complex. ACBD3 levels are markedly elevated in the striatum of HD patients, in a striatal cell line harboring polyglutamine repeats, and in the brains of HD mice. Moreover, ACBD3 deletion abolishes HD neurotoxicity, which is increased by ACBD3 overexpression. Enhanced levels of ACBD3 elicited by endoplasmic reticulum, mitochondrial, and Golgi stresses may account for HD-associated augmentation of ACBD3 and neurodegeneration.
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Affiliation(s)
- Juan I. Sbodio
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD. 21205, USA
| | - Bindu D. Paul
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD. 21205, USA
| | - Carolyn E. Machamer
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD. 21205, USA
| | - Solomon H. Snyder
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD. 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, MD. 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, MD. 21205, USA
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39
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Iacono G, Altafini C, Torre V. Early phase of plasticity-related gene regulation and SRF dependent transcription in the hippocampus. PLoS One 2013; 8:e68078. [PMID: 23935853 PMCID: PMC3720722 DOI: 10.1371/journal.pone.0068078] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 05/25/2013] [Indexed: 02/07/2023] Open
Abstract
Hippocampal organotypic cultures are a highly reliable in vitro model for studying neuroplasticity: in this paper, we analyze the early phase of the transcriptional response induced by a 20 µM gabazine treatment (GabT), a GABA-Ar antagonist, by using Affymetrix oligonucleotide microarray, RT-PCR based time-course and chromatin-immuno-precipitation. The transcriptome profiling revealed that the pool of genes up-regulated by GabT, besides being strongly related to the regulation of growth and synaptic transmission, is also endowed with neuro-protective and pro-survival properties. By using RT-PCR, we quantified a time-course of the transient expression for 33 of the highest up-regulated genes, with an average sampling rate of 10 minutes and covering the time interval [10∶90] minutes. The cluster analysis of the time-course disclosed the existence of three different dynamical patterns, one of which proved, in a statistical analysis based on results from previous works, to be significantly related with SRF-dependent regulation (p-value<0.05). The chromatin immunoprecipitation (chip) assay confirmed the rich presence of working CArG boxes in the genes belonging to the latter dynamical pattern and therefore validated the statistical analysis. Furthermore, an in silico analysis of the promoters revealed the presence of additional conserved CArG boxes upstream of the genes Nr4a1 and Rgs2. The chip assay confirmed a significant SRF signal in the Nr4a1 CArG box but not in the Rgs2 CArG box.
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Affiliation(s)
- Giovanni Iacono
- Department of Functional Analysis, International School for Advanced Studies, Trieste, Italy
| | - Claudio Altafini
- Department of Functional Analysis, International School for Advanced Studies, Trieste, Italy
| | - Vincent Torre
- Department of Functional Analysis, International School for Advanced Studies, Trieste, Italy
- IIT Italian Institute of Technology, Genova, Italy
- * E-mail:
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Gao J, Zhang C, Fu X, Yi Q, Tian F, Ning Q, Luo X. Effects of targeted suppression of glutaryl-CoA dehydrogenase by lentivirus-mediated shRNA and excessive intake of lysine on apoptosis in rat striatal neurons. PLoS One 2013; 8:e63084. [PMID: 23658800 PMCID: PMC3642093 DOI: 10.1371/journal.pone.0063084] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 03/29/2013] [Indexed: 12/31/2022] Open
Abstract
In glutaric aciduria type 1 (GA1), glutaryl-CoA dehydrogenase (GCDH) deficiency has been shown to be responsible for the accumulation of glutaric acid and striatal degeneration. However, the mechanisms by which GA1 induces striatal degeneration remain unclear. In this study, we aimed to establish a novel neuronal model of GA1 and to investigate the effects of GCDH deficiency and lysine-related metabolites on the viability of rat striatal neurons. Thus we constructed a lentiviral vector containing short hairpin RNA targeted against the GCDH gene expression (lentivirus-shRNA) in neurons. A virus containing a scrambled short hairpin RNA construct served as a control. Addition of lysine (5 mmol/L) was used to mimic hypermetabolism. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Apoptosis was assessed using Hoechst33342 staining and Annexin V-PE/7-AAD staining. The mitochondrial membrane potential (MPP) was monitored using tetramethylrhodamine methyl ester. The expression levels of caspases 3, 8, and 9 were determined by Western blotting. We found that lentivirus-shRNA induced apoptosis and decreased MMP levels in neurons, and addition of 5 mmol/L lysine enhanced this effect markedly. Lentivirus-shRNA upregulated the protein levels of caspases 3 and 9 regardless of the presence of 5 mmol/L lysine. The expression level of caspase 8 was higher in neurons co-treated with lentivirus-shRNA and 5 mmol/L lysine than in control. Benzyloxy-carbonyl-Val-Ala-Asp(OMe)-fluoromethylketone, a pan-caspase inhibitor, blocked the apoptosis induced by lentivirus-shRNA and 5 mmol/L lysine to a great extent. These results indicate that the targeted suppression of GCDH by lentivirus-mediated shRNA and excessive intake of lysine may be a useful cell model of GA1. These also suggest that GA1-induced striatal degeneration is partially caspase-dependent.
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MESH Headings
- Amino Acid Metabolism, Inborn Errors/enzymology
- Amino Acid Metabolism, Inborn Errors/metabolism
- Amino Acid Metabolism, Inborn Errors/pathology
- Animals
- Apoptosis/drug effects
- Apoptosis/genetics
- Base Sequence
- Biological Transport/genetics
- Brain Diseases, Metabolic/enzymology
- Brain Diseases, Metabolic/metabolism
- Brain Diseases, Metabolic/pathology
- Caspase Inhibitors/pharmacology
- Cell Survival/drug effects
- Cell Survival/genetics
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/genetics
- Gene Knockdown Techniques
- Glutaryl-CoA Dehydrogenase/deficiency
- Glutaryl-CoA Dehydrogenase/genetics
- Glutaryl-CoA Dehydrogenase/metabolism
- Lentivirus/genetics
- Lysine/metabolism
- Lysine/pharmacology
- Membrane Potential, Mitochondrial/drug effects
- Membrane Potential, Mitochondrial/genetics
- Neostriatum/cytology
- Neurons/cytology
- Neurons/drug effects
- Neurons/metabolism
- RNA, Small Interfering/genetics
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- Jinzhi Gao
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Cai Zhang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Fu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qin Yi
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fengyan Tian
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qin Ning
- Department of Infectious Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoping Luo
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- * E-mail:
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Rhes deletion is neuroprotective in the 3-nitropropionic acid model of Huntington's disease. J Neurosci 2013; 33:4206-10. [PMID: 23447628 DOI: 10.1523/jneurosci.3730-12.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although the mutated protein causing Huntington's disease (HD) is expressed throughout the body, the major pathology of HD is localized to the striatum of the brain. We previously reported that the striatal-enriched protein Rhes binds the mutated huntingtin protein and enhances its cytotoxicity. We now demonstrate that Rhes-deleted mice are dramatically protected from neurotoxicity and motor dysfunction in a striatal-specific model of HD elicited by 3-nitropropionic acid. This finding suggests that Rhes may, in part, determine the striatal selectivity of HD.
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Harrison LM, Lahoste GJ. The role of Rhes, Ras homolog enriched in striatum, in neurodegenerative processes. Exp Cell Res 2013; 319:2310-5. [PMID: 23583659 DOI: 10.1016/j.yexcr.2013.03.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 03/15/2013] [Accepted: 03/22/2013] [Indexed: 10/26/2022]
Abstract
Rhes is a small GTPase whose expression is highly enriched in striatum. It shares homology with Ras proteins, but also contains a C-terminal extension, thus suggesting additional functions. Signaling by 7 transmembrane receptors through heterotrimeric G proteins is inhibited by Rhes. However, perhaps the most remarkable feature of this small GTPase described thus far is that it can account for the selective vulnerability of the striatum in Huntington's Disease (HD). HD is an autosomal dominant neurodegenerative disease caused by a poly-glutamine expansion in the protein huntingtin. Despite the presence of huntingtin throughout the brain and the rest of the body, the striatum is selectively degenerated. Recent work shows that Rhes acts as an E3 ligase for attachment of SUMO (small ubiquitin-like modifier). As this post-translational modification decreases the formation of huntingtin aggregates and promotes cell death, this property of Rhes offers an explanation for selective striatal vulnerability in HD. In addition, the sequestering of Rhes through its binding to mutant huntingtin may decrease the ability of Rhes to perform vital physiological functions in the neuron. Thus, as Rhes is an attractive candidate for HD therapy, a thorough understanding of its physiological functions will allow for specific targeting of its pathological functions.
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Affiliation(s)
- Laura M Harrison
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, 2020 Gravier Street, New Orleans, LA 70112, USA.
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MicroRNA-22 (miR-22) overexpression is neuroprotective via general anti-apoptotic effects and may also target specific Huntington's disease-related mechanisms. PLoS One 2013; 8:e54222. [PMID: 23349832 PMCID: PMC3547907 DOI: 10.1371/journal.pone.0054222] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 12/10/2012] [Indexed: 11/19/2022] Open
Abstract
Background Whereas many causes and mechanisms of neurodegenerative diseases have been identified, very few therapeutic strategies have emerged in parallel. One possible explanation is that successful treatment strategy may require simultaneous targeting of more than one molecule of pathway. A new therapeutic approach to have emerged recently is the engagement of microRNAs (miRNAs), which affords the opportunity to target multiple cellular pathways simultaneously using a single sequence. Methodology/Principal Findings We identified miR-22 as a potentially neuroprotective miRNA based on its predicted regulation of several targets implicated in Huntington’s disease (histone deacetylase 4 (HDAC4), REST corepresor 1 (Rcor1) and regulator of G-protein signaling 2 (Rgs2)) and its diminished expression in Huntington’s and Alzheimer’s disease brains. We then tested the hypothesis that increasing cellular levels of miRNA-22 would achieve neuroprotection in in vitro models of neurodegeneration. As predicted, overexpression of miR-22 inhibited neurodegeneration in primary striatal and cortical cultures exposed to a mutated human huntingtin fragment (Htt171-82Q). Overexpression of miR-22 also decreased neurodegeneration in primary neuronal cultures exposed to 3-nitropropionic acid (3-NP), a mitochondrial complex II/III inhibitor. In addition, miR-22 improved neuronal viability in an in vitro model of brain aging. The mechanisms underlying the effects of miR-22 included a reduction in caspase activation, consistent with miR-22′s targeting the pro-apoptotic activities of mitogen-activated protein kinase 14/p38 (MAPK14/p38) and tumor protein p53-inducible nuclear protein 1 (Tp53inp1). Moreover, HD-specific effects comprised not only targeting HDAC4, Rcor1 and Rgs2 mRNAs, but also decreasing focal accumulation of mutant Htt-positive foci, which occurred via an unknown mechanism. Conclusions These data show that miR-22 has multipartite anti-neurodegenerative activities including the inhibition of apoptosis and the targeting of mRNAs implicated in the etiology of HD. These results motivate additional studies to evaluate the feasibility and therapeutic efficacy of manipulating miR-22 in vivo.
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Harrison LM. Rhes: a GTP-binding protein integral to striatal physiology and pathology. Cell Mol Neurobiol 2012; 32:907-18. [PMID: 22450871 DOI: 10.1007/s10571-012-9830-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 03/09/2012] [Indexed: 02/07/2023]
Abstract
Rhes, the Ras Homolog Enriched in Striatum, is a GTP-binding protein whose gene was discovered during a screen for mRNAs preferentially expressed in rodent striatum. This 266 amino acid protein is intermediate in size between small Ras-like GTP-binding proteins and α-subunits of heterotrimeric G proteins. It is most closely related to another Ras-like GTP-binding protein termed Dexras1 or AGS1. Although subsequent studies have shown that the rhes gene is expressed in other brain areas in addition to striatum, the striatal expression level is relatively high, and Rhes protein is likely to play a vital role in striatal physiology and pathology. Indeed, it has recently been shown to interact with the Huntingtin protein and play a pivotal role in the selective vulnerability of striatum in Huntington's disease (HD). Not surprisingly, Rhes can interact with multiple proteins to affect striatal physiology at multiple levels. Functional studies have indicated that Rhes plays a role in signaling by striatal G protein-coupled receptors (GPCR), although the details of the mechanism remain to be determined. Rhes has been shown to bind to both α- and β-subunits of heterotrimeric G proteins and to affect signaling by both Gi/o- and Gs/olf-coupled receptors. In this context, Rhes can be classified as a member of the family of accessory proteins to GPCR signaling. With documented effects in dopamine- and opioid-mediated behaviors, an interaction with thyroid hormone systems and a role in HD pathology, Rhes is emerging as an important protein in striatal physiology and pathology.
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Affiliation(s)
- Laura M Harrison
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
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Capucin does not modify the toxicity of a mutant Huntingtin fragment in vivo. Neurobiol Aging 2012; 33:1845.e5-6. [PMID: 22365050 DOI: 10.1016/j.neurobiolaging.2012.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 11/10/2011] [Accepted: 01/19/2012] [Indexed: 11/22/2022]
Abstract
Genes selectively expressed in the striatum may be involved in the preferential vulnerability of striatal neurons to Huntington's disease (HD). Here, we investigated whether perturbations of Capucin expression, which is enriched in the striatum and downregulated in Huntington's disease models, could modify the neurotoxicity induced by the injection of a lentiviral vector encoding a short N-terminal fragment of mutant Huntingtin (mHtt) into the mouse striatum. Neither constitutive Capucin deficiency in knockout mice nor lentiviral vector-mediated Capucin overexpression in the striatum of adult wild type mice significantly modified vulnerability to the mHtt fragment in vivo, suggesting that Capucin has no impact on mHtt toxicity.
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Seredenina T, Luthi-Carter R. What have we learned from gene expression profiles in Huntington's disease? Neurobiol Dis 2012; 45:83-98. [DOI: 10.1016/j.nbd.2011.07.001] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 06/24/2011] [Accepted: 07/01/2011] [Indexed: 12/22/2022] Open
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47
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Subramaniam S, Napolitano F, Mealer RG, Kim S, Errico F, Barrow R, Shahani N, Tyagi R, Snyder SH, Usiello A. Rhes, a striatal-enriched small G protein, mediates mTOR signaling and L-DOPA-induced dyskinesia. Nat Neurosci 2011; 15:191-3. [PMID: 22179112 PMCID: PMC3267880 DOI: 10.1038/nn.2994] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 10/26/2011] [Indexed: 12/19/2022]
Abstract
L–DOPA–induced dyskinesia, the rate–limiting side–effect in the therapy of Parkinson’s Disease, is mediated by activation of mTOR signaling in the striatum. We show that Rhes, a striatal–specific protein, binds to and activates mTOR. Moreover, Rhes deleted mice manifest reduced striatal mTOR signaling and diminished dyskinesia but maintain motor improvement upon L–DOPA treatment, implying therapeutic benefit for Rhes–binding drugs.
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Affiliation(s)
- Srinivasa Subramaniam
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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