1
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Juhl AD, Wüstner D. Pathways and Mechanisms of Cellular Cholesterol Efflux-Insight From Imaging. Front Cell Dev Biol 2022; 10:834408. [PMID: 35300409 PMCID: PMC8920967 DOI: 10.3389/fcell.2022.834408] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/04/2022] [Indexed: 12/24/2022] Open
Abstract
Cholesterol is an essential molecule in cellular membranes, but too much cholesterol can be toxic. Therefore, mammalian cells have developed complex mechanisms to remove excess cholesterol. In this review article, we discuss what is known about such efflux pathways including a discussion of reverse cholesterol transport and formation of high-density lipoprotein, the function of ABC transporters and other sterol efflux proteins, and we highlight their role in human diseases. Attention is paid to the biophysical principles governing efflux of sterols from cells. We also discuss recent evidence for cholesterol efflux by the release of exosomes, microvesicles, and migrasomes. The role of the endo-lysosomal network, lipophagy, and selected lysosomal transporters, such as Niemann Pick type C proteins in cholesterol export from cells is elucidated. Since oxysterols are important regulators of cellular cholesterol efflux, their formation, trafficking, and secretion are described briefly. In addition to discussing results obtained with traditional biochemical methods, focus is on studies that use established and novel bioimaging approaches to obtain insight into cholesterol efflux pathways, including fluorescence and electron microscopy, atomic force microscopy, X-ray tomography as well as mass spectrometry imaging.
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Affiliation(s)
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, PhyLife, Physical Life Sciences, University of Southern Denmark, Odense, Denmark
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2
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Kumar AV, Lapierre LR. Location, location, location: subcellular protein partitioning in proteostasis and aging. Biophys Rev 2021; 13:931-941. [PMID: 35047088 PMCID: PMC8724496 DOI: 10.1007/s12551-021-00890-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/01/2021] [Indexed: 12/25/2022] Open
Abstract
Somatic maintenance and cell survival rely on proper protein homeostasis to ensure reliable functions across the cell and to prevent proteome collapse. Maintaining protein folding and solubility is central to proteostasis and is coordinated by protein synthesis, chaperoning, and degradation capacities. An emerging aspect that influences proteostasis is the dynamic protein partitioning across different subcellular structures and compartments. Here, we review recent literature related to nucleocytoplasmic partitioning of proteins, nuclear and cytoplasmic quality control mechanisms, and their impact on the development of age-related diseases. We also highlight new points of entry to modulate spatially-regulated proteostatic mechanisms to delay aging.
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Affiliation(s)
- Anita V. Kumar
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 USA
| | - Louis R. Lapierre
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 USA
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3
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Kolla R, Gopinath P, Ricci J, Reif A, Rostami I, Lashuel HA. A New Chemoenzymatic Semisynthetic Approach Provides Insight into the Role of Phosphorylation beyond Exon1 of Huntingtin and Reveals N-Terminal Fragment Length-Dependent Distinct Mechanisms of Aggregation. J Am Chem Soc 2021; 143:9798-9812. [PMID: 34161085 DOI: 10.1021/jacs.1c03108] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Huntington's disease is a neurodegenerative disorder caused by the expansion of a polyglutamine repeat (>36Q) in the N-terminal domain of the huntingtin protein (Htt), which renders the protein or fragments thereof more prone to aggregate and form inclusions. Although several Htt N-terminal fragments of different lengths have been identified within Htt inclusions, most studies on the mechanisms, sequence, and structural determinants of Htt aggregation have focused on the Httexon1 (Httex1). Herein, we investigated the aggregation properties of mutant N-terminal Htt fragments of various lengths (Htt171, Htt140, and Htt104) in comparison to mutant Httex1 (mHttex1). We also present a new chemoenzymatic semisynthetic strategy that enables site-specific phosphorylation of Htt beyond Httex1. These advances yielded insights into how post-translational modifications (PTMs) and structured domains beyond Httex1 influence aggregation mechanisms, kinetics, and fibril morphology of longer N-terminal Htt fragments. We demonstrate that phosphorylation at T107 significantly slows the aggregation of mHtt171, whereas phosphorylation at T107 and S116 accelerates the aggregation, underscoring the importance of crosstalk between different PTMs. The mHtt171 proteins aggregate via a different mechanism and form oligomers and fibrillar aggregates with morphological properties that are distinct from that of mHttex1. These observations suggest that different N-terminal fragments could have distinct aggregation mechanisms and that a single polyQ-targeting antiaggregation strategy may not effectively inhibit the aggregation of all N-terminal Htt fragments. Finally, our results underscore the need for further studies to investigate the aggregation mechanisms of Htt fragments and how the various fragments interact with each other and influence Htt toxicity and disease progression.
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Affiliation(s)
- Rajasekhar Kolla
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Pushparathinam Gopinath
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jonathan Ricci
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Andreas Reif
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Iman Rostami
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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4
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Bozzi M, Sciandra F. Molecular Mechanisms Underlying Muscle Wasting in Huntington's Disease. Int J Mol Sci 2020; 21:ijms21218314. [PMID: 33167595 PMCID: PMC7664236 DOI: 10.3390/ijms21218314] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by pathogenic expansions of the triplet cytosine-adenosine-guanosine (CAG) within the Huntingtin gene. These expansions lead to a prolongation of the poly-glutamine stretch at the N-terminus of Huntingtin causing protein misfolding and aggregation. Huntingtin and its pathological variants are widely expressed, but the central nervous system is mainly affected, as proved by the wide spectrum of neurological symptoms, including behavioral anomalies, cognitive decline and motor disorders. Other hallmarks of HD are loss of body weight and muscle atrophy. This review highlights some key elements that likely provide a major contribution to muscle atrophy, namely, alteration of the transcriptional processes, mitochondrial dysfunction, which is strictly correlated to loss of energy homeostasis, inflammation, apoptosis and defects in the processes responsible for the protein quality control. The improvement of muscular symptoms has proven to slow the disease progression and extend the life span of animal models of HD, underlining the importance of a deep comprehension of the molecular mechanisms driving deterioration of muscular tissue.
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Affiliation(s)
- Manuela Bozzi
- Dipartimento Universitario di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore di Roma, Largo F. Vito 1, 00168 Roma, Italy
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”– SCITEC Sede di Roma, Largo F. Vito 1, 00168 Roma, Italy;
- Correspondence:
| | - Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”– SCITEC Sede di Roma, Largo F. Vito 1, 00168 Roma, Italy;
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5
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Landles C, Milton RE, Ali N, Flomen R, Flower M, Schindler F, Gomez-Paredes C, Bondulich MK, Osborne GF, Goodwin D, Salsbury G, Benn CL, Sathasivam K, Smith EJ, Tabrizi SJ, Wanker EE, Bates GP. Subcellular Localization And Formation Of Huntingtin Aggregates Correlates With Symptom Onset And Progression In A Huntington'S Disease Model. Brain Commun 2020; 2:fcaa066. [PMID: 32954323 PMCID: PMC7425396 DOI: 10.1093/braincomms/fcaa066] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/02/2020] [Accepted: 04/13/2020] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease is caused by the expansion of a CAG repeat within exon 1 of the HTT gene, which is unstable, leading to further expansion, the extent of which is brain region and peripheral tissue specific. The identification of DNA repair genes as genetic modifiers of Huntington's disease, that were known to abrogate somatic instability in Huntington's disease mouse models, demonstrated that somatic CAG expansion is central to disease pathogenesis, and that the CAG repeat threshold for pathogenesis in specific brain cells might not be known. We have previously shown that the HTT gene is incompletely spliced generating a small transcript that encodes the highly pathogenic exon 1 HTT protein. The longer the CAG repeat, the more of this toxic fragment is generated, providing a pathogenic consequence for somatic expansion. Here, we have used the R6/2 mouse model to investigate the molecular and behavioural consequences of expressing exon 1 HTT with 90 CAGs, a mutation that causes juvenile Huntington's disease, compared to R6/2 mice carrying ∼200 CAGs, a repeat expansion of a size rarely found in Huntington's disease patient's blood, but which has been detected in post-mortem brains as a consequence of somatic CAG repeat expansion. We show that nuclear aggregation occurred earlier in R6/2(CAG)90 mice and that this correlated with the onset of transcriptional dysregulation. Whereas in R6/2(CAG)200 mice, cytoplasmic aggregates accumulated rapidly and closely tracked with the progression of behavioural phenotypes and with end-stage disease. We find that aggregate species formed in the R6/2(CAG)90 brains have different properties to those in the R6/2(CAG)200 mice. Within the nucleus, they retain a diffuse punctate appearance throughout the course of the disease, can be partially solubilized by detergents and have a greater seeding potential in young mice. In contrast, aggregates from R6/2(CAG)200 brains polymerize into larger structures that appear as inclusion bodies. These data emphasize that a subcellular analysis, using multiple complementary approaches, must be undertaken in order to draw any conclusions about the relationship between HTT aggregation and the onset and progression of disease phenotypes.
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Affiliation(s)
- Christian Landles
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Rebecca E Milton
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Nadira Ali
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Rachel Flomen
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Michael Flower
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Franziska Schindler
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, 13125 Berlin, Germany and Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Casandra Gomez-Paredes
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Marie K Bondulich
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Georgina F Osborne
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Daniel Goodwin
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Grace Salsbury
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Caroline L Benn
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK.,LoQus23 Therapeutics, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Kirupa Sathasivam
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Edward J Smith
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Sarah J Tabrizi
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
| | - Erich E Wanker
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, 13125 Berlin, Germany and Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Gillian P Bates
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, Queen Square, WC1N 3BG, UK
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6
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Arbez N, He X, Huang Y, Ren M, Liang Y, Nucifora FC, Wang X, Pei Z, Tessarolo L, Smith WW, Ross CA. G2019S-LRRK2 mutation enhances MPTP-linked Parkinsonism in mice. Hum Mol Genet 2020; 29:580-590. [PMID: 31813996 PMCID: PMC7068031 DOI: 10.1093/hmg/ddz271] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/03/2019] [Accepted: 11/04/2019] [Indexed: 01/30/2023] Open
Abstract
Parkinson's disease (PD) is a common neurodegenerative disease with a heterogeneous etiology that involves genetic and environmental factors or exogenous. Current LRRK2 PD animal models only partly reproduce the characteristics of the disease with very subtle dopaminergic neuron degeneration. We developed a new model of PD that combines a sub-toxic MPTP insult to the G2019S-LRRK2 mutation. Our newly generated mice, overexpressing mutant G2019S-LRRK2 protein in the brain, displayed a mild, age-dependent progressive motor impairment, but no reduction of lifespan. Cortical neurons from G2019S-LRRK2 mice showed an increased vulnerability to stress insults, compared with neurons overexpressing wild-type WT-LRRK2, or non-transgenic (nTg) neurons. The exposure of LRRK2 transgenic mice to a sub-toxic dose of MPTP resulted in severe motor impairment, selective loss of dopamine neurons and increased astrocyte activation, whereas nTg mice with MPTP exposure showed no deficits. Interestingly, mice overexpressing WT-LRRK2 showed a significant impairment that was milder than for the mutant G2019S-LRRK2 mice. L-DOPA treatments could partially improve the movement impairments but did not protect the dopamine neuron loss. In contrast, treatments with an LRRK2 kinase inhibitor significantly reduced the dopaminergic neuron degeneration in this interaction model. Our studies provide a novel LRRK2 gene-MPTP interaction PD mouse model, and a useful tool for future studies of PD pathogenesis and therapeutic intervention.
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Affiliation(s)
- Nicolas Arbez
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - XiaoFei He
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - Yong Huang
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - Mark Ren
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - Yideng Liang
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - Frederick C Nucifora
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - Xiaofang Wang
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - Zhong Pei
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - Lino Tessarolo
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Wanli W Smith
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
| | - Christopher A Ross
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine,Baltimore, MD 21287, USA
- Departments of Neurology, Pharmacology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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7
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Gintonin, a ginseng-derived ingredient, as a novel therapeutic strategy for Huntington's disease: Activation of the Nrf2 pathway through lysophosphatidic acid receptors. Brain Behav Immun 2019; 80:146-162. [PMID: 30853569 DOI: 10.1016/j.bbi.2019.03.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 03/02/2019] [Accepted: 03/05/2019] [Indexed: 12/13/2022] Open
Abstract
Gintonin (GT), a ginseng-derived lysophosphatidic acid receptor ligand, regulates various cellular effects and represses inflammation. However, little is known about the potential value of GT regarding inflammation in the neurodegenerative diseases, such as Huntington's disease (HD). In this study, we investigated whether GT could ameliorate the neurological impairment and striatal toxicity in cellular or animal model of HD. Pre-, co-, and onset-treatment with GT (25, 50, or 100 mg/kg/day, p.o.) alleviated the severity of neurological impairment and lethality following 3-nitropropionic acid (3-NPA). Pretreatment with GT also attenuated mitochondrial dysfunction i.e. succinate dehydrogenase and MitoSOX activities, apoptosis, microglial activation, and mRNA expression of inflammatory mediators i.e. IL-1β, IL-6, TNF-α, COX-2, and iNOS in the striatum after 3-NPA-intoxication. Its action mechanism was associated with lysophosphatidic acid receptors (LPARs) and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway activations and the inhibition of mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) signaling pathways. These beneficial effects of GT were neutralized by pre-inhibiting LPARs with Ki16425 (a LPAR1/3 antagonist). Interestingly, GT reduced cell death and mutant huntingtin (HTT) aggregates in STHdh cells. It also mitigated neurological impairment in mice with adeno-associated viral (AAV) vector serotype DJ-mediated overexpression of N171-82Q-mutant HTT in the striatum. Taken together, our findings firstly suggested that GT has beneficial effects with a wide therapeutic time-window in 3-NPA-induced striatal toxicity by antioxidant and anti-inflammatory activities through LPA. In addition, GT exerts neuroprotective effects in STHdh cells and AAV vector-infected model of HD. Thus GT might be an innovative therapeutic candidate to treat HD-like syndromes.
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8
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Morton AJ, Skillings EA, Wood NI, Zheng Z. Antagonistic pleiotropy in mice carrying a CAG repeat expansion in the range causing Huntington's disease. Sci Rep 2019; 9:37. [PMID: 30631090 PMCID: PMC6328633 DOI: 10.1038/s41598-018-37102-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/28/2018] [Indexed: 02/06/2023] Open
Abstract
Antagonist pleiotropy, where a gene exerts a beneficial effect at early stages and a deleterious effect later on in an animal’s life, may explain the evolutionary persistence of devastating genetic diseases such as Huntington’s disease (HD). To date, however, there is little direct experimental evidence to support this theory. Here, we studied a transgenic mouse carrying the HD mutation with a repeat of 50 CAGs (R6/2_50) that is within the pathological range of repeats causing adult-onset disease in humans. R6/2_50 mice develop characteristic HD brain aggregate pathology, with aggregates appearing predominantly in the striatum and cortex. However, they show few signs of disease in their lifetime. On the contrary, R6/2_50 mice appear to benefit from carrying the mutation. They have extended lifespans compared to wildtype (WT) mice, and male mice show enhanced fecundity. Furthermore, R6/2_50 mice outperform WT mice on the rotarod and show equal or better performance in the two choice discrimination task than WT mice. This novel mouse line provides direct experimental evidence that, although the HD mutation causes a fatal neurodegenerative disorder, there may be premorbid benefits of carrying the mutation.
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Affiliation(s)
- A J Morton
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom.
| | - E A Skillings
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - N I Wood
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - Z Zheng
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
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9
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Jang M, Lee SE, Cho IH. Adeno-Associated Viral Vector Serotype DJ-Mediated Overexpression of N171-82Q-Mutant Huntingtin in the Striatum of Juvenile Mice Is a New Model for Huntington's Disease. Front Cell Neurosci 2018; 12:157. [PMID: 29946240 PMCID: PMC6005874 DOI: 10.3389/fncel.2018.00157] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/18/2018] [Indexed: 12/14/2022] Open
Abstract
Huntington's disease (HD) is an autosomal-dominant inherited neurodegenerative disorder characterized by motor, psychiatric and cognitive symptoms. HD is caused by an expansion of CAG repeats in the huntingtin (HTT) gene in various areas of the brain including striatum. There are few suitable animal models to study the pathogenesis of HD and validate therapeutic strategies. Recombinant adeno-associated viral (AAV) vectors successfully transfer foreign genes to the brain of adult mammalians. In this article, we report a novel mouse model of HD generated by bilateral intrastriatal injection of AAV vector serotype DJ (AAV-DJ) containing N171-82Q mutant HTT (82Q) and N171-18Q wild type HTT (18Q; sham). The AAV-DJ-82Q model displayed motor dysfunctions in pole and rotarod tests beginning 4 weeks after viral infection in juvenile mice (8 weeks after birth). They showed behaviors reflecting neurodegeneration. They also showed increased apoptosis, robust glial activation and upregulated representative inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6), mediators (cyclooxygenase-2 and inducible nitric oxide synthase) and signaling pathways (nuclear factor kappa B and signal transducer and activator of transcription 3 (STAT3)) in the striatum at 10 weeks after viral infection (14 weeks after birth) via successful transfection of mutant HTT into neurons, microglia, and astrocytes in the striatum. However, little evidence of any of these events was found in mice infected with the AAV-DJ-18Q expressing construct. Intrastriatal injection of AAV-DJ-82Q might be useful as a novel in vivo model to investigate the biology of truncated N-terminal fragment (N171) in the striatum and to explore the efficacy of therapeutic strategies for HD.
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Affiliation(s)
- Minhee Jang
- Department of Convergence Medical Science, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
| | - Seung Eun Lee
- Virus Facility, Research Animal Resource Center, Korea Institute of Science and Technology (KIST), Seoul, South Korea
| | - Ik-Hyun Cho
- Department of Convergence Medical Science, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
- Brain Korea 21 Plus Program and Institute of Korean Medicine, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
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10
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Kang I, Chu CT, Kaufman BA. The mitochondrial transcription factor TFAM in neurodegeneration: emerging evidence and mechanisms. FEBS Lett 2018; 592:793-811. [PMID: 29364506 PMCID: PMC5851836 DOI: 10.1002/1873-3468.12989] [Citation(s) in RCA: 175] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 12/30/2022]
Abstract
The mitochondrial transcription factor A, or TFAM, is a mitochondrial DNA (mtDNA)-binding protein essential for genome maintenance. TFAM functions in determining the abundance of the mitochondrial genome by regulating packaging, stability, and replication. More recently, TFAM has been shown to play a central role in the mtDNA stress-mediated inflammatory response. Emerging evidence indicates that decreased mtDNA copy number is associated with several aging-related pathologies; however, little is known about the association of TFAM abundance and disease. In this Review, we evaluate the potential associations of altered TFAM levels or mtDNA copy number with neurodegeneration. We also describe potential mechanisms by which mtDNA replication, transcription initiation, and TFAM-mediated endogenous danger signals may impact mitochondrial homeostasis in Alzheimer, Huntington, Parkinson, and other neurodegenerative diseases.
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Affiliation(s)
- Inhae Kang
- Department of Food Science and Nutrition, Jeju National University, Jeju, Korea
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine Center for Metabolic and Mitochondrial Medicine (C3M), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Charleen T. Chu
- Department of Pathology, Center for Neuroscience, Pittsburgh Institute for Neurodegenerative Diseases, Conformational Protein Diseases Center, and the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Brett A. Kaufman
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine Center for Metabolic and Mitochondrial Medicine (C3M), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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11
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Genetic Rodent Models of Huntington Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1049:29-57. [DOI: 10.1007/978-3-319-71779-1_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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12
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Abstract
The identification of the mutation causing Huntington's disease (HD) has led to the generation of a large number of mouse models. These models are used to further enhance our understanding of the mechanisms underlying the disease, as well as investigating and identifying therapeutic targets for this disorder. Here we review the transgenic, knock-in mice commonly used to model HD, as well those that have been generated to study specific disease mechanisms. We then provide a brief overview of the importance of standardizing the use of HD mice and describe brief protocols used for genotyping the mouse models used within the Bates Laboratory.
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Affiliation(s)
- Pamela P Farshim
- Department of Neurodegenerative Disease, Huntington's Disease Centre and Dementia Research Institute, University College London Institute of Neurology, London, WC1N 3BG, UK
| | - Gillian P Bates
- Department of Neurodegenerative Disease, Huntington's Disease Centre and Dementia Research Institute, University College London Institute of Neurology, London, WC1N 3BG, UK.
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13
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Weydt P, Dupuis L, Petersen Å. Thermoregulatory disorders in Huntington disease. HANDBOOK OF CLINICAL NEUROLOGY 2018; 157:761-775. [PMID: 30459039 DOI: 10.1016/b978-0-444-64074-1.00047-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Huntington disease (HD) is a paradigmatic autosomal-dominant adult-onset neurodegenerative disease. Since the identification of an abnormal expansion of a trinucleotide repeat tract in the huntingtin gene as the underlying genetic defect, a broad range of transgenic animal models of the disease has become available and these have helped to unravel the relevant molecular pathways in unprecedented detail. Of note, some of the most informative of these models develop thermoregulatory defects such as hypothermia, problems with adaptive thermogenesis, and an altered circadian temperature rhythm. Both central, e.g., in the hypothalamus and peripheral, i.e., the brown adipose tissue and skeletal muscle, problems contribute to the phenotype. Importantly, these structures and pathways are also affected in human HD. Yet, currently the evidence for bona fide thermodysregulation in human HD patients remains anecdotal. This may be due to a lack of reliable tools for monitoring body temperature in an outpatient setting. Regardless, study of the temperature phenotype has contributed to the identification of unexpected molecular targets, such as the PGC-1α pathway.
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Affiliation(s)
- Patrick Weydt
- Department of Neurodegenerative Diseases and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Bonn, Germany.
| | - Luc Dupuis
- Faculty of Medicine, University of Strasbourg, Strasbourg, France
| | - Åsa Petersen
- Translational Neuroendocrine Research Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
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14
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The CAG-polyglutamine repeat diseases: a clinical, molecular, genetic, and pathophysiologic nosology. HANDBOOK OF CLINICAL NEUROLOGY 2018; 147:143-170. [PMID: 29325609 DOI: 10.1016/b978-0-444-63233-3.00011-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Throughout the genome, unstable tandem nucleotide repeats can expand to cause a variety of neurologic disorders. Expansion of a CAG triplet repeat within a coding exon gives rise to an elongated polyglutamine (polyQ) tract in the resultant protein product, and accounts for a unique category of neurodegenerative disorders, known as the CAG-polyglutamine repeat diseases. The nine members of the CAG-polyglutamine disease family include spinal and bulbar muscular atrophy (SBMA), Huntington disease, dentatorubral pallidoluysian atrophy, and six spinocerebellar ataxias (SCA 1, 2, 3, 6, 7, and 17). All CAG-polyglutamine diseases are dominantly inherited, with the exception of SBMA, which is X-linked, and many CAG-polyglutamine diseases display anticipation, which is defined as increasing disease severity in successive generations of an affected kindred. Despite widespread expression of the different polyQ-expanded disease proteins throughout the body, each CAG-polyglutamine disease strikes a particular subset of neurons, although the mechanism for this cell-type selectivity remains poorly understood. While the different genes implicated in these disorders display amino acid homology only in the repeat tract domain, certain pathologic molecular processes have been implicated in almost all of the CAG-polyglutamine repeat diseases, including protein aggregation, proteolytic cleavage, transcription dysregulation, autophagy impairment, and mitochondrial dysfunction. Here we highlight the clinical and molecular genetic features of each distinct disorder, and then discuss common themes in CAG-polyglutamine disease pathogenesis, closing with emerging advances in therapy development.
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15
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Yu M, Fu Y, Liang Y, Song H, Yao Y, Wu P, Yao Y, Pan Y, Wen X, Ma L, Hexige S, Ding Y, Luo S, Lu B. Suppression of MAPK11 or HIPK3 reduces mutant Huntingtin levels in Huntington's disease models. Cell Res 2017; 27:1441-1465. [PMID: 29151587 PMCID: PMC5717400 DOI: 10.1038/cr.2017.113] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/14/2017] [Accepted: 08/08/2017] [Indexed: 12/13/2022] Open
Abstract
Most neurodegenerative disorders are associated with accumulation of disease-relevant proteins. Among them, Huntington disease (HD) is of particular interest because of its monogenetic nature. HD is mainly caused by cytotoxicity of the defective protein encoded by the mutant Huntingtin gene (HTT). Thus, lowering mutant HTT protein (mHTT) levels would be a promising treatment strategy for HD. Here we report two kinases HIPK3 and MAPK11 as positive modulators of mHTT levels both in cells and in vivo. Both kinases regulate mHTT via their kinase activities, suggesting that inhibiting these kinases may have therapeutic values. Interestingly, their effects on HTT levels are mHTT-dependent, providing a feedback mechanism in which mHTT enhances its own level thus contributing to mHTT accumulation and disease progression. Importantly, knockout of MAPK11 significantly rescues disease-relevant behavioral phenotypes in a knockin HD mouse model. Collectively, our data reveal new therapeutic entry points for HD and target-discovery approaches for similar diseases.
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Affiliation(s)
- Meng Yu
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yuhua Fu
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yijiang Liang
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Haikun Song
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yao Yao
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Peng Wu
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yuwei Yao
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yuyin Pan
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Xue Wen
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Lixiang Ma
- Department of Anatomy and Histology & Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Saiyin Hexige
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Yu Ding
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
| | - Shouqing Luo
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth, PL68BU, UK
| | - Boxun Lu
- State Key Laboratory of Medical Neurobiology, Huashan Hospital, School of Life Sciences, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
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16
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Zheng J, Yang J, Choe YJ, Hao X, Cao X, Zhao Q, Zhang Y, Franssens V, Hartl FU, Nyström T, Winderickx J, Liu B. Role of the ribosomal quality control machinery in nucleocytoplasmic translocation of polyQ-expanded huntingtin exon-1. Biochem Biophys Res Commun 2017; 493:708-717. [PMID: 28864412 DOI: 10.1016/j.bbrc.2017.08.126] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 08/28/2017] [Indexed: 10/19/2022]
Abstract
The subcellular localization of polyQ-expanded huntingtin exon1 (Httex1) modulates polyQ toxicity in models of Huntington's disease. Using genome-wide screens in a yeast model system, we report that the ribosome quality control (RQC) machinery, recently implicated in neurodegeneration, is a key determinant for the nucleocytoplasmic distribution of Httex1-103Q. Deletion of the RQC genes, LTN1 or RQC1, caused the accumulation of Httex1-103Q in the nucleus through a process that required the CAT-tail tagging activity of Rqc2 and transport via the nuclear pore complex. We provide evidence that nuclear accumulation of Httex1-103Q enhances its cytotoxicity, suggesting that the RQC machinery plays an important role in protecting cells against the adverse effects of polyQ expansion proteins.
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Affiliation(s)
- Ju Zheng
- Department of Chemistry and Molecular Biology, University of Gothenburg, S-413 90, Göteborg, Sweden; Department of Biology, Functional Biology, KU Leuven, 3001, Heverlee, Belgium
| | - Junsheng Yang
- Department of Chemistry and Molecular Biology, University of Gothenburg, S-413 90, Göteborg, Sweden
| | - Young-Jun Choe
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152, Germany
| | - Xinxin Hao
- Department of Chemistry and Molecular Biology, University of Gothenburg, S-413 90, Göteborg, Sweden
| | - Xiuling Cao
- Department of Chemistry and Molecular Biology, University of Gothenburg, S-413 90, Göteborg, Sweden
| | - Qian Zhao
- School of Life Sciences, Shandong University of Technology, 266 New Village West Road, Zhangdian District, Zibo, Shandong, China
| | - Yuejie Zhang
- School of Life Sciences, Shandong University of Technology, 266 New Village West Road, Zhangdian District, Zibo, Shandong, China
| | - Vanessa Franssens
- Department of Biology, Functional Biology, KU Leuven, 3001, Heverlee, Belgium
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152, Germany
| | - Thomas Nyström
- Department of Chemistry and Molecular Biology, University of Gothenburg, S-413 90, Göteborg, Sweden
| | - Joris Winderickx
- Department of Biology, Functional Biology, KU Leuven, 3001, Heverlee, Belgium
| | - Beidong Liu
- Department of Chemistry and Molecular Biology, University of Gothenburg, S-413 90, Göteborg, Sweden.
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17
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Chaibva M, Jawahery S, Pilkington AW, Arndt JR, Sarver O, Valentine S, Matysiak S, Legleiter J. Acetylation within the First 17 Residues of Huntingtin Exon 1 Alters Aggregation and Lipid Binding. Biophys J 2017; 111:349-362. [PMID: 27463137 DOI: 10.1016/j.bpj.2016.06.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 06/06/2016] [Accepted: 06/15/2016] [Indexed: 02/06/2023] Open
Abstract
Huntington's disease (HD) is a genetic neurodegenerative disorder caused by an expanded polyglutamine (polyQ) domain near the N-terminus of the huntingtin (htt) protein. Expanded polyQ leads to htt aggregation. The first 17 amino acids (Nt(17)) in htt comprise a lipid-binding domain that undergoes a number of posttranslational modifications that can modulate htt toxicity and subcellular localization. As there are three lysines within Nt(17), we evaluated the impact of lysine acetylation on htt aggregation in solution and on model lipid bilayers. Acetylation of htt-exon1(51Q) and synthetic truncated htt-exon 1 mimicking peptides (Nt(17)-Q35-P10-KK) was achieved using a selective covalent label, sulfo-N-hydroxysuccinimide (NHSA). With this treatment, all three lysine residues (K6, K9, and K15) in Nt(17) were significantly acetylated. N-terminal htt acetylation retarded fibril formation in solution and promoted the formation of larger globular aggregates. Acetylated htt also bound lipid membranes and disrupted the lipid bilayer morphology less aggressively compared with the wild-type. Computational studies provided mechanistic insights into how acetylation alters the interaction of Nt(17) with lipid membranes. Our results highlight that N-terminal acetylation influences the aggregation of htt and its interaction with lipid bilayers.
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Affiliation(s)
- Maxmore Chaibva
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Sudi Jawahery
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Albert W Pilkington
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - James R Arndt
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Olivia Sarver
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Stephen Valentine
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Silvina Matysiak
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland; Biophysics Program, Institute for Physical Chemistry and Technology, University of Maryland, College Park, Maryland.
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia; NanoSAFE, West Virginia University, Morgantown, West Virginia; Center for Neurosciences, West Virginia University, Morgantown, West Virginia.
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18
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Grima JC, Daigle JG, Arbez N, Cunningham KC, Zhang K, Ochaba J, Geater C, Morozko E, Stocksdale J, Glatzer JC, Pham JT, Ahmed I, Peng Q, Wadhwa H, Pletnikova O, Troncoso JC, Duan W, Snyder SH, Ranum LPW, Thompson LM, Lloyd TE, Ross CA, Rothstein JD. Mutant Huntingtin Disrupts the Nuclear Pore Complex. Neuron 2017; 94:93-107.e6. [PMID: 28384479 PMCID: PMC5595097 DOI: 10.1016/j.neuron.2017.03.023] [Citation(s) in RCA: 241] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/30/2017] [Accepted: 03/13/2017] [Indexed: 01/01/2023]
Abstract
Huntington's disease (HD) is caused by an expanded CAG repeat in the Huntingtin (HTT) gene. The mechanism(s) by which mutant HTT (mHTT) causes disease is unclear. Nucleocytoplasmic transport, the trafficking of macromolecules between the nucleus and cytoplasm, is tightly regulated by nuclear pore complexes (NPCs) made up of nucleoporins (NUPs). Previous studies offered clues that mHTT may disrupt nucleocytoplasmic transport and a mutation of an NUP can cause HD-like pathology. Therefore, we evaluated the NPC and nucleocytoplasmic transport in multiple models of HD, including mouse and fly models, neurons transfected with mHTT, HD iPSC-derived neurons, and human HD brain regions. These studies revealed severe mislocalization and aggregation of NUPs and defective nucleocytoplasmic transport. HD repeat-associated non-ATG (RAN) translation proteins also disrupted nucleocytoplasmic transport. Additionally, overexpression of NUPs and treatment with drugs that prevent aberrant NUP biology also mitigated this transport defect and neurotoxicity, providing future novel therapy targets.
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Affiliation(s)
- Jonathan C Grima
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - J Gavin Daigle
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nicolas Arbez
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kathleen C Cunningham
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ke Zhang
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Joseph Ochaba
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Charlene Geater
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Eva Morozko
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Jennifer Stocksdale
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Jenna C Glatzer
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jacqueline T Pham
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ishrat Ahmed
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Qi Peng
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Harsh Wadhwa
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Olga Pletnikova
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Juan C Troncoso
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Wenzhen Duan
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Solomon H Snyder
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Laura P W Ranum
- Center for NeuroGenetics, Departments of Molecular Genetics and Microbiology and Neurology, College of Medicine, Genetics Institute, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Leslie M Thompson
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Thomas E Lloyd
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christopher A Ross
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jeffrey D Rothstein
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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19
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Fruhmann G, Seynnaeve D, Zheng J, Ven K, Molenberghs S, Wilms T, Liu B, Winderickx J, Franssens V. Yeast buddies helping to unravel the complexity of neurodegenerative disorders. Mech Ageing Dev 2017; 161:288-305. [DOI: 10.1016/j.mad.2016.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/22/2016] [Accepted: 05/02/2016] [Indexed: 12/31/2022]
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20
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Lin L, Park JW, Ramachandran S, Zhang Y, Tseng YT, Shen S, Waldvogel HJ, Curtis MA, Faull RLM, Troncoso JC, Pletnikova O, Ross CA, Davidson BL, Xing Y. Transcriptome sequencing reveals aberrant alternative splicing in Huntington's disease. Hum Mol Genet 2016; 25:3454-3466. [PMID: 27378699 DOI: 10.1093/hmg/ddw187] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 06/11/2016] [Accepted: 06/14/2016] [Indexed: 12/25/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG expansion in the gene-encoding Huntingtin (HTT). Transcriptome dysregulation is a major feature of HD pathogenesis, as revealed by a large body of work on gene expression profiling of tissues from human HD patients and mouse models. These studies were primarily focused on transcriptional changes affecting steady-state overall gene expression levels using microarray based approaches. A major missing component, however, has been the study of transcriptome changes at the post-transcriptional level, such as alternative splicing. Alternative splicing is a critical mechanism for expanding regulatory and functional diversity from a limited number of genes, and is particularly complex in the mammalian brain. Here we carried out a deep RNA-seq analysis of the BA4 (Brodmann area 4) motor cortex from seven human HD brains and seven controls to systematically discover aberrant alternative splicing events and characterize potential associated splicing factors in HD. We identified 593 differential alternative splicing events between HD and control brains. Using two expanded panels with a total of 108 BA4 tissues from patients and controls, we identified four splicing factors exhibiting significantly altered expression levels in HD patient brains. Moreover, follow-up molecular analyses of one splicing factor PTBP1 revealed its impact on disease-associated splicing patterns in HD. Collectively, our data provide genomic evidence for widespread splicing dysregulation in HD brains, and suggest the role of aberrant alternative splicing in the pathogenesis of HD.
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Affiliation(s)
- Lan Lin
- Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Juw Won Park
- Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Shyam Ramachandran
- The Raymond G Perelman Center for Cellular and Molecular Therapy, The Children's Hospital of Philadelphia, PA, USA
| | - Yida Zhang
- Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Yu-Ting Tseng
- Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Shihao Shen
- Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Henry J Waldvogel
- Department of Anatomy and Medical Imaging and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Department of Anatomy and Medical Imaging and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Department of Anatomy and Medical Imaging and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Juan C Troncoso
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Olga Pletnikova
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christopher A Ross
- Division of Neurobiology; Departments of Psychiatry, Neurology Neuroscience, and Pharmacology; and Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Beverly L Davidson
- The Raymond G Perelman Center for Cellular and Molecular Therapy, The Children's Hospital of Philadelphia, PA, USA .,The Department of Pathology & Laboratory Medicine, The University of Pennsylvania, PA 19104, USA
| | - Yi Xing
- Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
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21
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Veldman MB, Rios-Galdamez Y, Lu XH, Gu X, Qin W, Li S, Yang XW, Lin S. The N17 domain mitigates nuclear toxicity in a novel zebrafish Huntington's disease model. Mol Neurodegener 2015; 10:67. [PMID: 26645399 PMCID: PMC4673728 DOI: 10.1186/s13024-015-0063-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 11/30/2015] [Indexed: 01/14/2023] Open
Abstract
Background Although the genetic cause for Huntington’s disease (HD) has been known for over 20 years, the mechanisms that cause the neurotoxicity and behavioral symptoms of this disease are not well understood. One hypothesis is that N-terminal fragments of the HTT protein are the causative agents in HD and that peptide sequences adjacent to the poly-glutamine (Q) repeats modify its toxicity. Here we test the function of the N-terminal 17 amino acids (N17) in the context of the exon 1 fragment of HTT in a novel, inducible zebrafish model of HD. Results Deletion of N17 coupled with 97Q expansion (mHTT-ΔN17-exon1) resulted in a robust, rapidly progressing movement deficit, while fish with intact N17 and 97Q expansion (mHTT-exon1) have more delayed-onset movement deficits with slower progression. The level of mHTT-ΔN17-exon1 protein was significantly higher than mHTT-exon1, although the mRNA level of each transgene was marginally different, suggesting that N17 may regulate HTT protein stability in vivo. In addition, cell lineage specific induction of the mHTT-ΔN17-exon1 transgene in neurons was sufficient to recapitulate the consequences of ubiquitous transgene expression. Within neurons, accelerated nuclear accumulation of the toxic HTT fragment was observed in mHTT-ΔN17-exon1 fish, demonstrating that N17 also plays an important role in sub-cellular localization in vivo. Conclusions We have developed a novel, inducible zebrafish model of HD. These animals exhibit a progressive movement deficit reminiscent of that seen in other animal models and human patients. Deletion of the N17 terminal amino acids of the huntingtin fragment results in an accelerated HD-like phenotype that may be due to enhanced protein stability and nuclear accumulation of HTT. These transgenic lines will provide a valuable new tool to study mechanisms of HD at the behavioral, cellular, and molecular levels. Future experiments will be focused on identifying genetic modifiers, mechanisms and therapeutics that alleviate polyQ aggregation in the nucleus of neurons. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0063-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matthew B Veldman
- Department of Molecular, Cell and Developmental Biology, University of California-Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Yesenia Rios-Galdamez
- Department of Molecular, Cell and Developmental Biology, University of California-Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Xiao-Hong Lu
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, Los Angeles, USA.,Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, Los Angeles, USA.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Xiaofeng Gu
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, Los Angeles, USA.,Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, Los Angeles, USA.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Wei Qin
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Song Li
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - X William Yang
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, Los Angeles, USA.,Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, Los Angeles, USA.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Shuo Lin
- Department of Molecular, Cell and Developmental Biology, University of California-Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA. .,Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
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22
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Milewski M, Gawliński P, Bąk D, Matysiak A, Bal J. Complex interplay between the length and composition of the huntingtin-derived peptides modulates the intracellular behavior of the N-terminal fragments of mutant huntingtin. Eur J Cell Biol 2015; 94:179-89. [PMID: 25773959 DOI: 10.1016/j.ejcb.2015.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 01/04/2023] Open
Abstract
Diverse subcellular localizations of the huntingtin-containing inclusion bodies are frequently suspected of reflecting crucial divisions between different cellular pathways contributing to the pathophysiology of Huntington's disease. Here, we use a panel of different N-terminal huntingtin fragments overexpressed in transfected neuronal and non-neuronal cells to demonstrate that it is the length of the N-terminal huntingtin fragments rather than a presence of any specific amino acid sequences that determines the ratio between the nuclear and cytoplasmic inclusion bodies. Importantly, the length of those fragments does also seem to strongly influence the folding of the aggregating huntingtin species, as indicated by the apparent differences in their accessibility for different antibodies directed against particular subdomains within the N-terminal part of huntingtin, although these differences do not correlate with the peptides' ability to efficiently aggregate within the cell nucleus. Furthermore, the relatively long huntingtin fragment containing 588 amino acids of the reference sequence shows intracellular behavior that is substantially different from that exhibited by its shorter counterparts (containing either 171, 120, 89 or 64 amino acids), as this rarely aggregating peptide is not only accumulating in cytoplasmic inclusions of slightly different morphology but is also most strongly affected by the FLAG-tagging procedure that unexpectedly induces (or enhances) autophagy-related processes. Together, our results reveal a significant heterogeneity of the huntingtin accumulation patterns that are observed at the cellular level. These patterns are not only strongly dependent on both the length and the amino acid composition of the N-terminal huntingtin peptides but also seem to engage different cellular mechanisms implicated in the pathogenesis of Huntington's disease, including the non-proteasomal degradation of potentially toxic huntingtin forms.
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Affiliation(s)
- Michał Milewski
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland.
| | - Paweł Gawliński
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Daniel Bąk
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Agata Matysiak
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland; Institute of Genetics and Biotechnology, Warsaw University, Warsaw, Poland
| | - Jerzy Bal
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
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Abstract
The proper folding of proteins is continuously challenged by intrinsic and extrinsic stresses, and the accumulation of toxic misfolded proteins is associated with many human diseases. Eukaryotic cells have evolved a complex network of protein quality control pathways to protect the proteome, and these pathways are specialized for each subcellular compartment. While many details have been elucidated for how the cytosol and endoplasmic reticulum counteract proteotoxic stress, relatively little is known about the pathways protecting the nucleus from protein misfolding. Proper maintenance of nuclear proteostasis has important implications in preserving genomic integrity, as well as for aging and disease. Here, we offer a conceptual framework for how proteostasis is maintained in this organelle. We define the particular requirements that must be considered for the nucleus to manage proteotoxic stress, summarize the known and implicated pathways of nuclear protein quality control, and identify the unresolved questions in the field.
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Affiliation(s)
- Yoko Shibata
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA
| | - Richard I Morimoto
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA.
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25
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From pathways to targets: understanding the mechanisms behind polyglutamine disease. BIOMED RESEARCH INTERNATIONAL 2014; 2014:701758. [PMID: 25309920 PMCID: PMC4189765 DOI: 10.1155/2014/701758] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 09/03/2014] [Indexed: 12/27/2022]
Abstract
The history of polyglutamine diseases dates back approximately 20 years to the discovery of a polyglutamine repeat in the androgen receptor of SBMA followed by the identification of similar expansion mutations in Huntington's disease, SCA1, DRPLA, and the other spinocerebellar ataxias. This common molecular feature of polyglutamine diseases suggests shared mechanisms in disease pathology and neurodegeneration of disease specific brain regions. In this review, we discuss the main pathogenic pathways including proteolytic processing, nuclear shuttling and aggregation, mitochondrial dysfunction, and clearance of misfolded polyglutamine proteins and point out possible targets for treatment.
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26
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Valor LM. Transcription, epigenetics and ameliorative strategies in Huntington's Disease: a genome-wide perspective. Mol Neurobiol 2014; 51:406-23. [PMID: 24788684 PMCID: PMC4309905 DOI: 10.1007/s12035-014-8715-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 04/11/2014] [Indexed: 12/18/2022]
Abstract
Transcriptional dysregulation in Huntington’s disease (HD) is an early event that shapes the brain transcriptome by both the depletion and ectopic activation of gene products that eventually affect survival and neuronal functions. Disruption in the activity of gene expression regulators, such as transcription factors, chromatin-remodeling proteins, and noncoding RNAs, accounts for the expression changes observed in multiple animal and cellular models of HD and in samples from patients. Here, I review the recent advances in the study of HD transcriptional dysregulation and its causes to finally discuss the possible implications in ameliorative strategies from a genome-wide perspective. To date, the use of genome-wide approaches, predominantly based on microarray platforms, has been successful in providing an extensive catalog of differentially regulated genes, including biomarkers aimed at monitoring the progress of the pathology. Although still incipient, the introduction of combined next-generation sequencing techniques is enhancing our comprehension of the mechanisms underlying altered transcriptional dysregulation in HD by providing the first genomic landscapes associated with epigenetics and the occupancy of transcription factors. In addition, the use of genome-wide approaches is becoming more and more necessary to evaluate the efficacy and safety of ameliorative strategies and to identify novel mechanisms of amelioration that may help in the improvement of current preclinical therapeutics. Finally, the major conclusions obtained from HD transcriptomics studies have the potential to be extrapolated to other neurodegenerative disorders.
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Affiliation(s)
- Luis M Valor
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant, 03550, Alicante, Spain,
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27
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Gallagher PS, Oeser ML, Abraham AC, Kaganovich D, Gardner RG. Cellular maintenance of nuclear protein homeostasis. Cell Mol Life Sci 2014; 71:1865-79. [PMID: 24305949 PMCID: PMC3999211 DOI: 10.1007/s00018-013-1530-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 11/04/2013] [Accepted: 11/19/2013] [Indexed: 12/11/2022]
Abstract
The accumulation and aggregation of misfolded proteins is the primary hallmark for more than 45 human degenerative diseases. These devastating disorders include Alzheimer's, Parkinson's, Huntington's, and amyotrophic lateral sclerosis. Over 15 degenerative diseases are associated with the aggregation of misfolded proteins specifically in the nucleus of cells. However, how the cell safeguards the nucleus from misfolded proteins is not entirely clear. In this review, we discuss what is currently known about the cellular mechanisms that maintain protein homeostasis in the nucleus and protect the nucleus from misfolded protein accumulation and aggregation. In particular, we focus on the chaperones found to localize to the nucleus during stress, the ubiquitin-proteasome components enriched in the nucleus, the signaling systems that might be present in the nucleus to coordinate folding and degradation, and the sites of misfolded protein deposition associated with the nucleus.
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Affiliation(s)
- Pamela S Gallagher
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
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28
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Kumar A, Vaish M, Ratan RR. Transcriptional dysregulation in Huntington's disease: a failure of adaptive transcriptional homeostasis. Drug Discov Today 2014; 19:956-62. [PMID: 24662036 DOI: 10.1016/j.drudis.2014.03.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 03/14/2014] [Indexed: 01/02/2023]
Abstract
Huntington's disease (HD) is a signature polyglutamine disorder. An enduring theory of HD pathogenesis has involved dysregulation of transcription. Indeed, transcriptional regulatory proteins can be modulated to overcome cardinal features of HD-modeled mice, and efforts to move these into human studies are ongoing. Here, we discuss a unifying hypothesis emerging from these studies, which is that HD represents the pathological disruption of evolutionarily conserved adaptive gene programs to counteract oxidative stress, mitochondrial dysfunction and accumulation of misfolded proteins. Transcriptional dyshomeostasis of adaptive genes is further exacerbated by repression of genes involved in normal synaptic activity or growth factor signaling.
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Affiliation(s)
- Amit Kumar
- Burke Medical Research Institute, White Plains, NY 10065, USA; Brain and Mind Research Institute, Weill Medical College, Cornell University, White Plains, NY 10605, USA.
| | - Manisha Vaish
- Burke Medical Research Institute, White Plains, NY 10065, USA
| | - Rajiv R Ratan
- Burke Medical Research Institute, White Plains, NY 10065, USA; Brain and Mind Research Institute, Weill Medical College, Cornell University, White Plains, NY 10605, USA; Department of Neurology, Weill Medical College, Cornell University, White Plains, NY 10605, USA.
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29
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Pathological implications of nucleic acid interactions with proteins associated with neurodegenerative diseases. Biophys Rev 2014; 6:97-110. [PMID: 28509960 DOI: 10.1007/s12551-013-0132-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 12/03/2013] [Indexed: 10/25/2022] Open
Abstract
Protein misfolding disorders (PMDs) refer to a group of diseases related to the misfolding of particular proteins that aggregate and deposit in the cells and tissues of humans and other mammals. The mechanisms that trigger protein misfolding and aggregation are still not fully understood. Increasing experimental evidence indicates that abnormal interactions between PMD-related proteins and nucleic acids (NAs) can induce conformational changes. Here, we discuss these protein-NA interactions and address the role of deoxyribonucleic (DNA) and ribonucleic (RNA) acid molecules in the conformational conversion of different proteins that aggregate in PMDs, such as Alzheimer's, Parkinson's, and prion diseases. Studies on the affinity, stability, and specificity of proteins involved in neurodegenerative diseases and NAs are specifically addressed. A landscape of reciprocal effects resulting from the binding of prion proteins, amyloid-β peptides, tau proteins, huntingtin, and α-synuclein are presented here to clarify the possible role of NAs, not only as encoders of genetic information but also in triggering PMDs.
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30
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Maiuri T, Woloshansky T, Xia J, Truant R. The huntingtin N17 domain is a multifunctional CRM1 and Ran-dependent nuclear and cilial export signal. Hum Mol Genet 2013; 22:1383-94. [PMID: 23297360 PMCID: PMC3596850 DOI: 10.1093/hmg/dds554] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 12/14/2012] [Accepted: 12/27/2012] [Indexed: 11/12/2022] Open
Abstract
The first 17 amino acids of Huntington's disease (HD) protein, huntingtin, comprise an amphipathic alpha-helical domain that can target huntingtin to the endoplasmic reticulum (ER). N17 is phosphorylated at two serines, shown to be important for disease development in genetic mouse models, and shown to be modified by agents that reverse the disease phenotype in an HD mouse model. Here, we show that the hydrophobic face of N17 comprises a consensus CRM1/exportin-dependent nuclear export signal, and that this nuclear export activity can be affected by serine phospho-mimetic mutants. We define the precise residues that comprise this nuclear export sequence (NES) as well as the interaction of the NES, but not phospho-mimetic mutants, with the CRM1 nuclear export factor. We show that the nuclear localization of huntingtin depends upon the RanGTP/GDP gradient, and that N17 phosphorylation can also distinguish localization of endogenous huntingtin between the basal body and stalk of the primary cilium. We present a mechanism and multifunctional role for N17 in which phosphorylation of N17 not only releases huntingtin from the ER to allow nuclear entry, but also prevents nuclear export during a transient stress response event to increase the levels of nuclear huntingtin and to regulate huntingtin access to the primary cilium. Thus, N17 is a master localization signal of huntingtin that can mediate huntingtin localization between the cytoplasm, nucleus and primary cilium. This localization can be regulated by signaling, and is misregulated in HD.
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Affiliation(s)
| | | | | | - R. Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1200 Main Street West, Hamilton, ON, CanadaL8N3Z5
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31
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Zheng Z, Li A, Holmes BB, Marasa JC, Diamond MI. An N-terminal nuclear export signal regulates trafficking and aggregation of Huntingtin (Htt) protein exon 1. J Biol Chem 2013; 288:6063-71. [PMID: 23319588 PMCID: PMC3585045 DOI: 10.1074/jbc.m112.413575] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 01/08/2013] [Indexed: 11/06/2022] Open
Abstract
Huntington disease is a dominantly inherited neurodegenerative condition caused by polyglutamine expansion in the N terminus of the huntingtin protein (Htt). The first 17 amino acids (N17) of Htt play a key role in regulating its toxicity and aggregation. Both nuclear export and cytoplasm retention functions have been ascribed to N17. We have determined that N17 acts as a nuclear export sequence (NES) within Htt exon and when fused to yellow fluorescent protein. We have defined amino acids within N17 that constitute the nuclear export sequence (NES). Mutation of any of the conserved residues increases nuclear accumulation of Htt exon 1. Nuclear export of Htt is sensitive to leptomycin B and is reduced by knockdown of exportin 1. In HEK293 cells, NES mutations decrease overall Htt aggregation but increase the fraction of cells with nuclear inclusions. In primary cultured neurons, NES mutations increase nuclear accumulation and increase overall aggregation. This work defines a bona fide nuclear export sequence within N17 and links it to effects on protein aggregation. This may help explain the important role of N17 in controlling Htt toxicity.
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Affiliation(s)
| | - Aimin Li
- From the Departments of Neurology and
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Tsvetkov AS, Ando DM, Finkbeiner S. Longitudinal imaging and analysis of neurons expressing polyglutamine-expanded proteins. Methods Mol Biol 2013; 1017:1-20. [PMID: 23719904 DOI: 10.1007/978-1-62703-438-8_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Misfolded proteins have been implicated in most of the major neurodegenerative diseases, and identifying drugs and pathways that protect neurons from the toxicity of misfolded proteins is of paramount importance. We invented a form of automated imaging and analysis called robotic microscopy that is well suited to the study of neurodegeneration. It enables the monitoring of large cohorts of individual neurons over their lifetimes as they undergo neurodegeneration. With automated analysis, multiple endpoints in neurons can be measured, including survival. Statistical approaches, typically reserved for engineering and clinical medicine, can be applied to these data in an unbiased fashion to discover whether factors contribute positively or negatively to neuronal fate and to quantify the importance of their contribution. Ultimately, multivariate dynamic models can be constructed from these data, which can provide a systems-level understanding of the neurodegenerative disease process and guide the rationale for the development of therapies.
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Figiel M, Szlachcic WJ, Switonski PM, Gabka A, Krzyzosiak WJ. Mouse models of polyglutamine diseases: review and data table. Part I. Mol Neurobiol 2012; 46:393-429. [PMID: 22956270 PMCID: PMC3461215 DOI: 10.1007/s12035-012-8315-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 07/29/2012] [Indexed: 12/23/2022]
Abstract
Polyglutamine (polyQ) disorders share many similarities, such as a common mutation type in unrelated human causative genes, neurological character, and certain aspects of pathogenesis, including morphological and physiological neuronal alterations. The similarities in pathogenesis have been confirmed by findings that some experimental in vivo therapy approaches are effective in multiple models of polyQ disorders. Additionally, mouse models of polyQ diseases are often highly similar between diseases with respect to behavior and the features of the disease. The common features shared by polyQ mouse models may facilitate the investigation of polyQ disorders and may help researchers explore the mechanisms of these diseases in a broader context. To provide this context and to promote the understanding of polyQ disorders, we have collected and analyzed research data about the characterization and treatment of mouse models of polyQ diseases and organized them into two complementary Excel data tables. The data table that is presented in this review (Part I) covers the behavioral, molecular, cellular, and anatomic characteristics of polyQ mice and contains the most current knowledge about polyQ mouse models. The structure of this data table is designed in such a way that it can be filtered to allow for the immediate retrieval of the data corresponding to a single mouse model or to compare the shared and unique aspects of many polyQ models. The second data table, which is presented in another publication (Part II), covers therapeutic research in mouse models by summarizing all of the therapeutic strategies employed in the treatment of polyQ disorders, phenotypes that are used to examine the effects of the therapy, and therapeutic outcomes.
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Affiliation(s)
- Maciej Figiel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland.
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34
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Chaturvedi RK, Hennessey T, Johri A, Tiwari SK, Mishra D, Agarwal S, Kim YS, Beal MF. Transducer of regulated CREB-binding proteins (TORCs) transcription and function is impaired in Huntington's disease. Hum Mol Genet 2012; 21:3474-88. [PMID: 22589249 DOI: 10.1093/hmg/dds178] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Huntington's disease (HD) is an incurable neurological disorder caused by an abnormal glutamine repeat expansion in the huntingtin (Htt) protein. In the present studies, we investigated the role of Transducers of Regulated cAMP response element-binding (CREB) protein activity (TORCs) in HD, since TORCs play an important role in the expression of the transcriptional co-regulator peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), whose expression is impaired in HD. We found significantly decreased TORC1 expression levels in STHdhQ111 cells expressing mutant Htt, in the striatum of NLS-N171-82Q, R6/2 and HdhQ111 HD transgenic mice and in postmortem striatal tissue from HD patients. TORC1 overexpression in wild-type (WT) and Htt striatal cells increased CREB mRNA and protein levels, PGC-1α promoter activity, mRNA expression of the PGC-1α, NRF-1, Tfam and CytC genes, mitochondrial DNA content, mitochondrial activity and mitochondrial membrane potential. TORC1 overexpression also increased the resistance of striatal cells to 3-nitropropionic (3-NP) acid-mediated toxicity. In cultured WT and mutant Htt striatal cells, small hairpin RNA-mediated TORC1 knockdown resulted in decreased PGC-1α expression and increased susceptibility to 3-NP-induced toxicity. Overexpression of PGC-1α partially prevented TORC1 knockdown-mediated increased susceptibility of Htt striatal cells to 3-NP. Specific knockdown of TORC1 in the striatum of NLS-N171-82Q HD transgenic mice induced neurodegeneration. Lastly, knockdown of Htt prevents transcriptional repression of TORC1 and CREB in Htt striatal cells. These findings show that impaired expression and function of TORC1, which results in a reduction in PGC-1α, plays an important role in mitochondrial dysfunction in HD.
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Affiliation(s)
- Rajnish Kumar Chaturvedi
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, NY 10065, USA.
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A Mouse Model of Blast Injury to Brain: Initial Pathological, Neuropathological, and Behavioral Characterization. J Neuropathol Exp Neurol 2011; 70:399-416. [DOI: 10.1097/nen.0b013e3182189f06] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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36
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Chan WM, Tsoi H, Wu CC, Wong CH, Cheng TC, Li HY, Lau KF, Shaw PC, Perrimon N, Chan HYE. Expanded polyglutamine domain possesses nuclear export activity which modulates subcellular localization and toxicity of polyQ disease protein via exportin-1. Hum Mol Genet 2011; 20:1738-50. [PMID: 21300695 DOI: 10.1093/hmg/ddr049] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Polyglutamine (polyQ) diseases are a group of late-onset, progressive neurodegenerative disorders caused by CAG trinucleotide repeat expansion in the coding region of disease genes. The cell nucleus is an important site of pathology in polyQ diseases, and transcriptional dysregulation is one of the pathologic hallmarks observed. In this study, we showed that exportin-1 (Xpo1) regulates the nucleocytoplasmic distribution of expanded polyQ protein. We found that expanded polyQ protein, but not its unexpanded form, possesses nuclear export activity and interacts with Xpo1. Genetic manipulation of Xpo1 expression levels in transgenic Drosophila models of polyQ disease confirmed the specific nuclear export role of Xpo1 on expanded polyQ protein. Upon Xpo1 knockdown, the expanded polyQ protein was retained in the nucleus. The nuclear disease protein enhanced polyQ toxicity by binding to heat shock protein (hsp) gene promoter and abolished hsp gene induction. Further, we uncovered a developmental decline of Xpo1 protein levels in vivo that contributes to the accumulation of expanded polyQ protein in the nucleus of symptomatic polyQ transgenic mice. Taken together, we first showed that Xpo1 is a nuclear export receptor for expanded polyQ domain, and our findings establish a direct link between protein nuclear export and the progressive nature of polyQ neurodegeneration.
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Affiliation(s)
- Wing Man Chan
- Laboratory of Drosophila Research, Faculty of Science, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
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Increased inflammatory signaling and lethality of influenza H1N1 by nuclear thioredoxin-1. PLoS One 2011; 6:e18918. [PMID: 21526215 PMCID: PMC3078150 DOI: 10.1371/journal.pone.0018918] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2010] [Accepted: 03/25/2011] [Indexed: 01/30/2023] Open
Abstract
Background Cell culture studies show that the antioxidant thiol protein, thioredoxin-1 (Trx1), translocates to cell nuclei during stress, facilitates DNA binding of transcription factors NF-κB and glucocorticoid receptor (GR) and potentiates signaling in immune cells. Excessive proinflammatory signaling in vivo contributes to immune hyper-responsiveness and disease severity, but no studies have addressed whether nuclear Trx1 mediates such responses. Methodology/Principal Findings Transgenic mice (Tg) expressing human Trx1 (hTrx1) with added nuclear localization signal (NLS) showed broad tissue expression and nuclear localization. The role of nuclear Trx1 in inflammatory signaling was examined in Tg and wild-type (WT) mice following infection with influenza (H1N1) virus. Results showed that Tg mice had earlier and more extensive NF-κB activation, increased TNF-α and IL-6 expression, greater weight loss, slower recovery and increased mortality compared to WT. Decreased plasma glutathione (GSH) and oxidized plasma GSH/GSSG redox potential (EhGSSG) following infection in Tg mice showed that the increased nuclear thiol antioxidant caused a paradoxical downstream oxidative stress. An independent test of this nuclear reductive stress showed that glucocorticoid-induced thymocyte apoptosis was increased by NLS-Trx1. Conclusion/Significance Increased Trx1 in cell nuclei can increase severity of disease responses by potentiation of redox-sensitive transcription factor activation.
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Duzdevich D, Li J, Whang J, Takahashi H, Takeyasu K, Dryden DTF, Morton AJ, Edwardson JM. Unusual structures are present in DNA fragments containing super-long Huntingtin CAG repeats. PLoS One 2011; 6:e17119. [PMID: 21347256 PMCID: PMC3037965 DOI: 10.1371/journal.pone.0017119] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 01/21/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In the R6/2 mouse model of Huntington's disease (HD), expansion of the CAG trinucleotide repeat length beyond about 300 repeats induces a novel phenotype associated with a reduction in transcription of the transgene. METHODOLOGY/PRINCIPAL FINDINGS We analysed the structure of polymerase chain reaction (PCR)-generated DNA containing up to 585 CAG repeats using atomic force microscopy (AFM). As the number of CAG repeats increased, an increasing proportion of the DNA molecules exhibited unusual structural features, including convolutions and multiple protrusions. At least some of these features are hairpin loops, as judged by cross-sectional analysis and sensitivity to cleavage by mung bean nuclease. Single-molecule force measurements showed that the convoluted DNA was very resistant to untangling. In vitro replication by PCR was markedly reduced, and TseI restriction enzyme digestion was also hindered by the abnormal DNA structures. However, significantly, the DNA gained sensitivity to cleavage by the Type III restriction-modification enzyme, EcoP15I. CONCLUSIONS/SIGNIFICANCE "Super-long" CAG repeats are found in a number of neurological diseases and may also appear through CAG repeat instability. We suggest that unusual DNA structures associated with super-long CAG repeats decrease transcriptional efficiency in vitro. We also raise the possibility that if these structures occur in vivo, they may play a role in the aetiology of CAG repeat diseases such as HD.
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Affiliation(s)
- Daniel Duzdevich
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Jinliang Li
- Laragen, Inc., Culver City, California, United States of America
| | - Jhoon Whang
- Laragen, Inc., Culver City, California, United States of America
| | - Hirohide Takahashi
- Laboratory of Plasma Membrane and Nuclear Signaling, Graduate School of Biostudies, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto, Japan
| | - Kunio Takeyasu
- Laboratory of Plasma Membrane and Nuclear Signaling, Graduate School of Biostudies, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto, Japan
| | - David T. F. Dryden
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, United Kingdom
| | - A. Jennifer Morton
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (AJM); (JME)
| | - J. Michael Edwardson
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (AJM); (JME)
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Havel LS, Wang CE, Wade B, Huang B, Li S, Li XJ. Preferential accumulation of N-terminal mutant huntingtin in the nuclei of striatal neurons is regulated by phosphorylation. Hum Mol Genet 2011; 20:1424-37. [PMID: 21245084 DOI: 10.1093/hmg/ddr023] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
An expanded polyglutamine tract (>37 glutamines) in the N-terminal region of huntingtin (htt) causes htt to accumulate in the nucleus, leading to transcriptional dysregulation in Huntington disease (HD). In HD knock-in mice that express full-length mutant htt at the endogenous level, mutant htt preferentially accumulates in the nuclei of striatal neurons, which are affected most profoundly in HD. The mechanism underlying this preferential nuclear accumulation of mutant htt in striatal neurons remains unknown. Here, we report that serine 16 (S16) in htt is important for the generation of small N-terminal fragments that are able to accumulate in the nucleus and form aggregates. Phosphorylation of N-terminal S16 in htt promotes the nuclear accumulation of small N-terminal fragments and reduces the interaction of N-terminal htt with the nuclear pore complex protein Tpr. Mouse brain striatal tissues show increased S16 phosphorylation and a decreased association between mutant N-terminal htt and Tpr. These findings provide mechanistic insight into the nuclear accumulation of mutant htt and the selective neuropathology of HD, revealing potential therapeutic targets for treating this disease.
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Affiliation(s)
- Lauren S Havel
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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40
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Abstract
It has been more than 17 years since the causative mutation for Huntington's disease was discovered as the expansion of the triplet repeat in the N-terminal portion of the Huntingtin (HTT) gene. In the intervening time, researchers have discovered a great deal about Huntingtin's involvement in a number of cellular processes. However, the role of Huntingtin in the key pathogenic mechanism leading to neurodegeneration in the disease process has yet to be discovered. Here, we review the body of knowledge that has been uncovered since gene discovery and include discussions of the HTT gene, CAG triplet repeat expansion, HTT expression, protein features, posttranslational modifications, and many of its known protein functions and interactions. We also highlight potential pathogenic mechanisms that have come to light in recent years.
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Affiliation(s)
- Karen N McFarland
- Department of Neurology, University of Florida, Gainesville, FL 32610-0236, USA.
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41
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The composition of the polyglutamine-containing proteins influences their co-aggregation properties. Cell Biol Int 2010; 34:933-42. [PMID: 20515443 DOI: 10.1042/cbi20090474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The sequestration of crucial cellular proteins into insoluble aggregates formed by the polypeptides containing expanded polyglutamine tracts has been proposed to be the key mechanism responsible for the abnormal cell functioning in the so-called polyglutamine diseases. To evaluate to what extent the ability of polyglutamine sequences to recruit other proteins into the intracellular aggregates depends on the composition of the aggregating peptide, we analysed the co-aggregation properties of the N-terminal fragment of huntingtin fused with unrelated non-aggregating and/or self-aggregating peptides. We show that the ability of the mutated N-terminal huntingtin fragment to sequester non-related proteins can be significantly increased by fusion with the non-aggregating reporter protein [GFP (green fluorescence protein)]. By contrast, fusion with the self-aggregating C-terminal fragment of the CFTR (cystic fibrosis transmembrane conductance regulator) dramatically reduces the sequestration of related non-fused huntingtin fragments. We also demonstrate that the co-aggregation of different non-fused N-terminal huntingtin fragments depends on their length, with long fragments of the wild-type huntingtin not only excluded from the nuclear inclusions, but also very inefficiently sequestered into the cytoplasmic aggregates formed by the short fragments of mutant protein. Additionally, our results suggest that atypical intracellular aggregation patterns, which include unusual distribution and/or morphology of protein aggregates, are associated with altered ability of accumulating proteins to co-aggregate with other peptides.
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Quantitative relationships between huntingtin levels, polyglutamine length, inclusion body formation, and neuronal death provide novel insight into huntington's disease molecular pathogenesis. J Neurosci 2010; 30:10541-50. [PMID: 20685997 DOI: 10.1523/jneurosci.0146-10.2010] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An expanded polyglutamine (polyQ) stretch in the protein huntingtin (htt) induces self-aggregation into inclusion bodies (IBs) and causes Huntington's disease (HD). Defining precise relationships between early observable variables and neuronal death at the molecular and cellular levels should improve our understanding of HD pathogenesis. Here, we used an automated microscope that tracks thousands of neurons individually over their entire lifetime to quantify interconnected relationships between early variables, such as htt levels, polyQ length, and IB formation, and neuronal death in a primary striatal model of HD. The resulting model revealed that mutant htt increases the risk of death by tonically interfering with homeostatic coping mechanisms rather than producing accumulated damage to the neuron, htt toxicity is saturable, the rate-limiting steps for inclusion body formation and death can be traced to different conformational changes in monomeric htt, and IB formation reduces the impact of the starting levels of htt of a neuron on its risk of death. Finally, the model that emerges from our quantitative measurements places critical limits on the potential mechanisms by which mutant htt might induce neurodegeneration, which should help direct future research.
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Chaturvedi RK, Calingasan NY, Yang L, Hennessey T, Johri A, Beal MF. Impairment of PGC-1alpha expression, neuropathology and hepatic steatosis in a transgenic mouse model of Huntington's disease following chronic energy deprivation. Hum Mol Genet 2010; 19:3190-205. [PMID: 20529956 DOI: 10.1093/hmg/ddq229] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We investigated the ability of AMP-activated protein kinase (AMPK) to activate PPARgamma coactivator-1alpha (PGC-1alpha) in the brain, liver and brown adipose tissue (BAT) of the NLS-N171-82Q transgenic mouse model of Huntington's disease (HD). In the striatum of the HD mice, the baseline levels of PGC-1alpha, NRF1, NRF2, Tfam, COX-II, PPARdelta, CREB and ERRalpha mRNA and mitochondrial DNA (mtDNA), were significantly reduced. Administration of the creatine analog beta guanidinopropionic acid (GPA) reduced ATP and PCr levels and increased AMPK mRNA in both the cerebral cortex and striatum. Treatment with GPA significantly increased expression of PGC-1alpha, NRF1, Tfam and downstream genes in the striatum and cerebral cortex of wild-type (WT) mice, but there was no effect on these genes in the HD mice. The striatum of the untreated HD mice showed microvacuolation in the neuropil, as well as gliosis and huntingtin aggregates, which were exacerbated by treatment with GPA. GPA treatment produced a significant increase in mtDNA in the cerebral cortex and striatum of WT mice, but not in HD mice. The HD mice treated with GPA had impaired activation of liver PGC-1alpha and developed hepatic steatosis with accumulation of lipids, degeneration of hepatocytes and impaired activation of gluconeogenesis. The BAT in the HD mice showed vacuolation due to accumulation of neutral lipids, and age-dependent impairment of UCP-1 activation and temperature regulation. Impaired activation of PGC-1alpha, therefore, plays an important role in the behavioral phenotype, metabolic disturbances and pathology of HD, which suggests the possibility that agents that enhance PGC-1alpha function will exert therapeutic benefits in HD patients.
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Affiliation(s)
- Rajnish K Chaturvedi
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10065, USA. /
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Intrabody gene therapy ameliorates motor, cognitive, and neuropathological symptoms in multiple mouse models of Huntington's disease. J Neurosci 2009; 29:13589-602. [PMID: 19864571 DOI: 10.1523/jneurosci.4286-09.2009] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disease resulting from the expansion of a glutamine repeat in the huntingtin (Htt) protein. Current therapies are directed at managing symptoms such as chorea and psychiatric disturbances. In an effort to develop a therapy directed at disease prevention we investigated the utility of highly specific, anti-Htt intracellular antibodies (intrabodies). We previously showed that V(L)12.3, an intrabody recognizing the N terminus of Htt, and Happ1, an intrabody recognizing the proline-rich domain of Htt, both reduce mHtt-induced toxicity and aggregation in cell culture and brain slice models of HD. Due to the different mechanisms of action of these two intrabodies, we then tested both in the brains of five mouse models of HD using a chimeric adeno-associated virus 2/1 (AAV2/1) vector with a modified CMV enhancer/chicken beta-actin promoter. V(L)12.3 treatment, while beneficial in a lentiviral model of HD, has no effect on the YAC128 HD model and actually increases severity of phenotype and mortality in the R6/2 HD model. In contrast, Happ1 treatment confers significant beneficial effects in a variety of assays of motor and cognitive deficits. Happ1 also strongly ameliorates the neuropathology found in the lentiviral, R6/2, N171-82Q, YAC128, and BACHD models of HD. Moreover, Happ1 significantly prolongs the life span of N171-82Q mice. These results indicate that increasing the turnover of mHtt using AAV-Happ1 gene therapy represents a highly specific and effective treatment in diverse mouse models of HD.
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Abstract
Huntington's disease (HD) is a relentless neurodegenerative disease that results in profound disability through a triad of motor, cognitive and neuropsychiatric symptoms. At present, there are very few therapeutic interventions available with the exception of a limited number of drugs that offer mild symptomatic relief. Although the genetic basis of the disease has been identified, the mechanisms behind the cellular pathogenesis are still not clear and as a result no candidate drugs with the potential for disease modification have been found clinically until now. One of the major limitations in assessing the usefulness of drug treatments in HD is the lack of well-designed, double-blind, placebo-controlled clinical trials. Most studies have been open-label, using a small number of patients and tend to concentrate on the motor features of the disease, primarily the chorea. This review discusses the treatments now used for HD before evaluating the newer drugs at present being explored in both the clinic and in the laboratory in mouse models of the disease.
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Affiliation(s)
- Sarah L Mason
- Cambridge Centre for Brain Repair, ED Adrian Building, Forvie Site, Robinson Way, Cambridge CB20PY, UK.
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Macedo-Ribeiro S, Cortes L, Maciel P, Carvalho AL. Nucleocytoplasmic shuttling activity of ataxin-3. PLoS One 2009; 4:e5834. [PMID: 19503814 PMCID: PMC2688764 DOI: 10.1371/journal.pone.0005834] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 05/08/2009] [Indexed: 01/02/2023] Open
Abstract
Spinocerebellar ataxia type-3, also known as Machado-Joseph Disease (MJD), is one of many inherited neurodegenerative disorders caused by polyglutamine-encoding CAG repeat expansions in otherwise unrelated genes. Disease protein misfolding and aggregation, often within the nucleus of affected neurons, characterize polyglutamine disorders. Several evidences have implicated the nucleus as the primary site of pathogenesis for MJD. However, the molecular determinants for the nucleocytoplasmic transport of human ataxin-3 (Atx3), the protein which is mutated in patients with MJD, are not characterized. In order to characterize the nuclear shuttling activity of Atx3, we performed yeast nuclear import assays and found that Atx3 is actively imported into the nucleus, by means of a classical nuclear localizing sequence formed by a cluster of lysine and arginine residues. On the other hand, when active nuclear export was inhibited using leptomycin B, a specific inhibitor of the nuclear export receptor CRM1, both endogenous Atx3 and transfected GFP-Atx3 accumulated inside the nucleus of a subpopulation of COS-7 cells, whereas both proteins are normally predominant in the cytoplasm. Additionally, using a Rev(1.4)-GFP nuclear export assay, we performed an extensive analysis of six putative aliphatic nuclear export motifs identified in Atx3 amino acid sequence. Although none of the tested peptide sequences were found to drive nuclear export when isolated, we have successfully mapped the region of Atx3 responsible for its CRM1-independent nuclear export activity. Curiously, the N-terminal Josephin domain alone is exported into the cytoplasm, but the nuclear export activity of Atx3 is significantly enhanced in a longer construct that is truncated after the two ubiquitin interaction motifs, upstream from the polyQ tract. Our data show that Atx3 is actively imported to and exported from the cell nucleus, and that its nuclear export activity is dependent on a motif located at its N-terminal region. Since pathological Atx3 aggregates in the nucleus of affected neurons in MJD, and there is in vivo evidence that nuclear localization of Atx3 is required for the manifestation of symptoms in MJD, defects in the nucleocytoplasmic shuttling activity of the protein may be involved in the nuclear accumulation and aggregation of expanded Atx3.
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Affiliation(s)
- Sandra Macedo-Ribeiro
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- * E-mail: (SMR); (ALC)
| | - Luísa Cortes
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Ana Luísa Carvalho
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Department of Zoology, University of Coimbra, Coimbra, Portugal
- * E-mail: (SMR); (ALC)
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Chaturvedi RK, Adhihetty P, Shukla S, Hennessy T, Calingasan N, Yang L, Starkov A, Kiaei M, Cannella M, Sassone J, Ciammola A, Squitieri F, Beal MF. Impaired PGC-1alpha function in muscle in Huntington's disease. Hum Mol Genet 2009; 18:3048-65. [PMID: 19460884 DOI: 10.1093/hmg/ddp243] [Citation(s) in RCA: 184] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigated the role of PPAR gamma coactivator 1alpha (PGC-1alpha) in muscle dysfunction in Huntington's disease (HD). We observed reduced PGC-1alpha and target genes expression in muscle of HD transgenic mice. We produced chronic energy deprivation in HD mice by administering the catabolic stressor beta-guanidinopropionic acid (GPA), a creatine analogue that reduces ATP levels, activates AMP-activated protein kinase (AMPK), which in turn activates PGC-1alpha. Treatment with GPA resulted in increased expression of AMPK, PGC-1alpha target genes, genes for oxidative phosphorylation, electron transport chain and mitochondrial biogenesis, increased oxidative muscle fibers, numbers of mitochondria and motor performance in wild-type, but not in HD mice. In muscle biopsies from HD patients, there was decreased PGC-1alpha, PGC-1beta and oxidative fibers. Oxygen consumption, PGC-1alpha, NRF1 and response to GPA were significantly reduced in myoblasts from HD patients. Knockdown of mutant huntingtin resulted in increased PGC-1alpha expression in HD myoblast. Lastly, adenoviral-mediated delivery of PGC-1alpha resulted increased expression of PGC-1alpha and markers for oxidative muscle fibers and reversal of blunted response for GPA in HD mice. These findings show that impaired function of PGC-1alpha plays a critical role in muscle dysfunction in HD, and that treatment with agents to enhance PGC-1alpha function could exert therapeutic benefits. Furthermore, muscle may provide a readily accessible tissue in which to monitor therapeutic interventions.
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Affiliation(s)
- Rajnish K Chaturvedi
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, NY 10065, USA.
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Warby SC, Doty CN, Graham RK, Shively J, Singaraja RR, Hayden MR. Phosphorylation of huntingtin reduces the accumulation of its nuclear fragments. Mol Cell Neurosci 2009; 40:121-7. [DOI: 10.1016/j.mcn.2008.09.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 09/18/2008] [Accepted: 09/25/2008] [Indexed: 01/04/2023] Open
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Dragatsis I, Goldowitz D, Del Mar N, Deng YP, Meade CA, Liu L, Sun Z, Dietrich P, Yue J, Reiner A. CAG repeat lengths > or =335 attenuate the phenotype in the R6/2 Huntington's disease transgenic mouse. Neurobiol Dis 2008; 33:315-30. [PMID: 19027857 DOI: 10.1016/j.nbd.2008.10.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 10/15/2008] [Accepted: 10/17/2008] [Indexed: 11/17/2022] Open
Abstract
With spontaneous elongation of the CAG repeat in the R6/2 transgene to > or =335, resulting in a transgene protein too large for passive entry into nuclei via the nuclear pore, we observed an abrupt increase in lifespan to >20 weeks, compared to the 12 weeks common in R6/2 mice with 150 repeats. In the > or =335 CAG mice, large ubiquitinated aggregates of mutant protein were common in neuronal dendrites and perikaryal cytoplasm, but intranuclear aggregates were small and infrequent. Message and protein for the > or =335 CAG transgene were reduced to one-third that in 150 CAG R6/2 mice. Neurological and neurochemical abnormalities were delayed in onset and less severe than in 150 CAG R6/2 mice. These findings suggest that polyQ length and pathogenicity in Huntington's disease may not be linearly related, and pathogenicity may be less severe with extreme repeats. Both diminished mutant protein and reduced nuclear entry may contribute to phenotype attenuation.
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Affiliation(s)
- I Dragatsis
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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Huntingtin modulates transcription, occupies gene promoters in vivo, and binds directly to DNA in a polyglutamine-dependent manner. J Neurosci 2008; 28:10720-33. [PMID: 18923047 DOI: 10.1523/jneurosci.2126-08.2008] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Transcriptional dysregulation is a central pathogenic mechanism in Huntington's disease, a fatal neurodegenerative disorder associated with polyglutamine (polyQ) expansion in the huntingtin (Htt) protein. In this study, we show that mutant Htt alters the normal expression of specific mRNA species at least partly by disrupting the binding activities of many transcription factors which govern the expression of the dysregulated mRNA species. Chromatin immunoprecipitation (ChIP) demonstrates Htt occupation of gene promoters in vivo in a polyQ-dependent manner, and furthermore, ChIP-on-chip and ChIP subcloning reveal that wild-type and mutant Htt exhibit differential genomic distributions. Exon 1 Htt binds DNA directly in the absence of other proteins and alters DNA conformation. PolyQ expansion increases Htt-DNA interactions, with binding to recognition elements of transcription factors whose function is altered in HD. Together, these findings suggest mutant Htt modulates gene expression through abnormal interactions with genomic DNA, altering DNA conformation and transcription factor binding.
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