301
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Naia L, Ribeiro MJ, Rego AC. Mitochondrial and metabolic-based protective strategies in Huntington's disease: the case of creatine and coenzyme Q. Rev Neurosci 2011; 23:13-28. [PMID: 22150069 DOI: 10.1515/rns.2011.060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 10/26/2011] [Indexed: 01/15/2023]
Abstract
Huntington's disease (HD) is a neurodegenerative genetic disorder caused by an expansion of CAG repeats in the HD gene encoding for huntingtin (Htt), resulting in progressive death of striatal neurons, with clinical symptoms of chorea, dementia and dramatic weight loss. Metabolic and mitochondrial dysfunction caused by the expanded polyglutamine sequence have been described along with other mechanisms of neurodegeneration previously described in human tissues and animal models of HD. In this review, we focus on mitochondrial and metabolic disturbances affecting both the central nervous system and peripheral cells, including mitochondrial DNA damage, mitochondrial complexes defects, loss of calcium homeostasis and transcriptional deregulation. Glucose abnormalities have also been described in peripheral tissues of HD patients and in HD animal and cellular models. Moreover, there are no effective neuroprotective treatments available in HD. Thus, we briefly discuss the role of creatine and coenzyme Q10 that target mitochondrial dysfunction and impaired bioenergetics and have been previously used in HD clinical trials.
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Affiliation(s)
- Luana Naia
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
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302
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Huntingtin aggregation kinetics and their pathological role in a Drosophila Huntington's disease model. Genetics 2011; 190:581-600. [PMID: 22095086 DOI: 10.1534/genetics.111.133710] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Huntington's disease is a neurodegenerative disorder resulting from expansion of a polyglutamine tract in the Huntingtin protein. Mutant Huntingtin forms intracellular aggregates within neurons, although it is unclear whether aggregates or more soluble forms of the protein represent the pathogenic species. To examine the link between aggregation and neurodegeneration, we generated Drosophila melanogaster transgenic strains expressing fluorescently tagged human huntingtin encoding pathogenic (Q138) or nonpathogenic (Q15) proteins, allowing in vivo imaging of Huntingtin expression and aggregation in live animals. Neuronal expression of pathogenic Huntingtin leads to pharate adult lethality, accompanied by formation of large aggregates within the cytoplasm of neuronal cell bodies and neurites. Live imaging and Fluorescence Recovery After Photobleaching (FRAP) analysis of pathogenic Huntingtin demonstrated that new aggregates can form in neurons within 12 hr, while preexisting aggregates rapidly accumulate new Huntingtin protein within minutes. To examine the role of aggregates in pathology, we conducted haplo-insufficiency suppressor screens for Huntingtin-Q138 aggregation or Huntingtin-Q138-induced lethality, using deficiencies covering ~80% of the Drosophila genome. We identified two classes of interacting suppressors in our screen: those that rescue viability while decreasing Huntingtin expression and aggregation and those that rescue viability without disrupting Huntingtin aggregation. The most robust suppressors reduced both soluble and aggregated Huntingtin levels, suggesting toxicity is likely to be associated with both forms of the mutant protein in Huntington's disease.
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303
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Hickey MA, Zhu C, Medvedeva V, Franich NR, Levine MS, Chesselet MF. Evidence for behavioral benefits of early dietary supplementation with CoEnzymeQ10 in a slowly progressing mouse model of Huntington's disease. Mol Cell Neurosci 2011; 49:149-57. [PMID: 22044764 DOI: 10.1016/j.mcn.2011.10.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 10/01/2011] [Accepted: 10/16/2011] [Indexed: 12/14/2022] Open
Abstract
Controversies surround the usefulness of Coenzyme Q10 (CoQ10) in Huntington's disease (HD), an autosomal dominant, fatal, neurodegenerative disease with no cure or disease modifying treatment. CoQ10, an endogenous substrate for electron transport and an anti-oxidant, has been shown in some but not all studies to improve symptoms and survival in mouse models of HD. Previous studies have been conducted in fast-progressing models that better mimic the juvenile forms of HD than the much more common middle-age onset form, possibly accounting for mixed results. Establishing the usefulness of CoQ10 to alter HD disease course in a model that better recapitulates the progressive features of the human disorder is important because clinical trials of CoQ10, which is safe and well tolerated, are being planned in patients. The CAG140 knock-in (KI) mouse model of HD in which an expanded (approximately 120) CAG repeat is inserted in the mouse gene provides a model of the mutation in the proper genomic and protein context. These mice display progressive motor, cognitive and emotional anomalies, transcriptional disturbances and late striatal degeneration. Homozygote mutant CAG140 KI mice and wild-type littermates were fed CoQ10 (0.2%, 0.6%) in chow, and behavioral and pathological markers of disease were examined. CoQ10 improved early behavioral deficits and normalized some transcriptional deficits without altering huntingtin aggregates in striatum. The lower dose (0.2%) was more beneficial than 0.6%. Similar to previous studies, this low dose also induced deleterious effects in open field and rotarod in WT mice, however these effects are of unclear clinical significance in view of the excellent safety profile of CoQ10 in humans. These data confirm that CoQ10 may be beneficial in HD but suggest that maximum benefit may be observed when treatment is begun at early stages of the disease and that dosage may be critical.
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Affiliation(s)
- Miriam A Hickey
- Department of Neurology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
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304
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Lee H, Noh JY, Oh Y, Kim Y, Chang JW, Chung CW, Lee ST, Kim M, Ryu H, Jung YK. IRE1 plays an essential role in ER stress-mediated aggregation of mutant huntingtin via the inhibition of autophagy flux. Hum Mol Genet 2011; 21:101-14. [PMID: 21954231 DOI: 10.1093/hmg/ddr445] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease (HD), an inherited neurodegenerative disorder, is caused by an expansion of cytosine-adenine-guanine repeats in the huntingtin gene. The aggregation of mutant huntingtin (mtHTT) and striatal cell loss are representative features to cause uncontrolled movement and cognitive defect in HD. However, underlying mechanism of mtHTT aggregation and cell toxicity remains still elusive. Here, to find new genes modulating mtHTT aggregation, we performed cell-based functional screening using the cDNA expression library and isolated IRE1 gene, one of endoplasmic reticulum (ER) stress sensors. Ectopic expression of IRE1 led to its self-activation and accumulated detergent-resistant mtHTT aggregates. Treatment of neuronal cells with ER stress insults, tunicamycin and thapsigargin, increased mtHTT aggregation via IRE1 activation. The kinase activity of IRE1, but not the endoribonuclease activity, was necessary to stimulate mtHTT aggregation and increased death of neuronal cells, including SH-SY5Y and STHdhQ111/111 huntingtin knock-in striatal cells. Interestingly, ER stress impaired autophagy flux via IRE1-TRAF2 pathway, thus enhancing cellular accumulation of mtHTT. Atg5 deficiency in M5-7 cells increased mtHTT aggregation but blocked ER stress-induced mtHTT aggregation. Further, ER stress markers including p-IRE1 and autophagy markers such as p62 were up-regulated exclusively in the striatal tissues of HD mouse models and in HD patients. Moreover, down-regulation of IRE1 expression rescues the rough-eye phenotype by mtHTT in a HD fly model. These results suggest that IRE1 plays an essential role in ER stress-mediated aggregation of mtHTT via the inhibition of autophagy flux and thus neuronal toxicity of mtHTT aggregates in HD.
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Affiliation(s)
- Huikyong Lee
- Global Research Laboratory, School of Biological Science/Bio-MAX Institute, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea
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305
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Abstract
The CNS is rich in cholesterol, which is essential for neuronal development and survival, synapse maturation, and optimal synaptic activity. Alterations in brain cholesterol homeostasis are linked to neurodegeneration. Studies have demonstrated that Huntington disease (HD), a progressive and fatal neurodegenerative disorder resulting from polyglutamine expansion in the huntingtin protein, is associated with changes in cellular cholesterol metabolism. Emerging evidence from human and animal studies indicates that attenuated brain sterol synthesis and accumulation of cholesterol in neuronal membranes represent two distinct mechanisms occurring in the presence of mutant huntingtin that influence neuronal survival. Increased knowledge of how changes in intraneuronal cholesterol metabolism influence the pathogenesis of HD will provide insights into the potential application of brain cholesterol regulation as a therapeutic strategy for this devastating disease.
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306
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Evers MM, Pepers BA, van Deutekom JCT, Mulders SAM, den Dunnen JT, Aartsma-Rus A, van Ommen GJB, van Roon-Mom WMC. Targeting several CAG expansion diseases by a single antisense oligonucleotide. PLoS One 2011; 6:e24308. [PMID: 21909428 PMCID: PMC3164722 DOI: 10.1371/journal.pone.0024308] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 08/04/2011] [Indexed: 12/16/2022] Open
Abstract
To date there are 9 known diseases caused by an expanded polyglutamine repeat, with the most prevalent being Huntington's disease. Huntington's disease is a progressive autosomal dominant neurodegenerative disorder for which currently no therapy is available. It is caused by a CAG repeat expansion in the HTT gene, which results in an expansion of a glutamine stretch at the N-terminal end of the huntingtin protein. This polyglutamine expansion plays a central role in the disease and results in the accumulation of cytoplasmic and nuclear aggregates. Here, we make use of modified 2'-O-methyl phosphorothioate (CUG)n triplet-repeat antisense oligonucleotides to effectively reduce mutant huntingtin transcript and protein levels in patient-derived Huntington's disease fibroblasts and lymphoblasts. The most effective antisense oligonucleotide, (CUG)(7), also reduced mutant ataxin-1 and ataxin-3 mRNA levels in spinocerebellar ataxia 1 and 3, respectively, and atrophin-1 in dentatorubral-pallidoluysian atrophy patient derived fibroblasts. This antisense oligonucleotide is not only a promising therapeutic tool to reduce mutant huntingtin levels in Huntington's disease but our results in spinocerebellar ataxia and dentatorubral-pallidoluysian atrophy cells suggest that this could also be applicable to other polyglutamine expansion disorders as well.
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Affiliation(s)
- Melvin M. Evers
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Barry A. Pepers
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | - Johan T. den Dunnen
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
- Leiden Genome Technology Center, Leiden University Medical Center, Leiden, The Netherlands
| | - Annemieke Aartsma-Rus
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Gert-Jan B. van Ommen
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
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307
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Ruiz M, Déglon N. Viral-mediated overexpression of mutant huntingtin to model HD in various species. Neurobiol Dis 2011; 48:202-11. [PMID: 21889981 DOI: 10.1016/j.nbd.2011.08.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 08/11/2011] [Accepted: 08/18/2011] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by an expansion of CAG repeats in the huntingtin (Htt) gene. Despite intensive efforts devoted to investigating the mechanisms of its pathogenesis, effective treatments for this devastating disease remain unavailable. The lack of suitable models recapitulating the entire spectrum of the degenerative process has severely hindered the identification and validation of therapeutic strategies. The discovery that the degeneration in HD is caused by a mutation in a single gene has offered new opportunities to develop experimental models of HD, ranging from in vitro models to transgenic primates. However, recent advances in viral-vector technology provide promising alternatives based on the direct transfer of genes to selected sub-regions of the brain. Rodent studies have shown that overexpression of mutant human Htt in the striatum using adeno-associated virus or lentivirus vectors induces progressive neurodegeneration, which resembles that seen in HD. This article highlights progress made in modeling HD using viral vector gene transfer. We describe data obtained with of this highly flexible approach for the targeted overexpression of a disease-causing gene. The ability to deliver mutant Htt to specific tissues has opened pathological processes to experimental analysis and allowed targeted therapeutic development in rodent and primate pre-clinical models.
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Affiliation(s)
- Marta Ruiz
- Atomic Energy Commission (CEA), Institute of Biomedical Imaging (I2BM), Molecular Imaging Research Center (MIRCen), Fontenay-aux-Roses, France
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308
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Jiang YJ, Che MX, Yuan JQ, Xie YY, Yan XZ, Hu HY. Interaction with polyglutamine-expanded huntingtin alters cellular distribution and RNA processing of huntingtin yeast two-hybrid protein A (HYPA). J Biol Chem 2011; 286:25236-45. [PMID: 21566141 PMCID: PMC3137094 DOI: 10.1074/jbc.m110.216333] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 04/14/2011] [Indexed: 11/06/2022] Open
Abstract
Huntington disease (HD) is an autosomal inherited disorder that causes the deterioration of brain cells. The polyglutamine (polyQ) expansion of huntingtin (Htt) is implicated in the pathogenesis of HD via interaction with an RNA splicing factor, Htt yeast two-hybrid protein A/forming-binding protein 11 (HYPA/FBP11). Besides the pathogenic polyQ expansion, Htt also contains a proline-rich region (PRR) located exactly in the C terminus to the polyQ tract. However, how the polyQ expansion influences the PRR-mediated protein interaction and how this abnormal interaction leads to the biological consequence remain elusive. Our NMR structural analysis indicates that the PRR motif of Htt cooperatively interacts with the tandem WW domains of HYPA through domain chaperoning effect of WW1 on WW2. The polyQ-expanded Htt sequesters HYPA to the cytosolic location and then significantly reduces the efficiency of pre-mRNA splicing. We propose that the toxic gain-of-function of the polyQ-expanded Htt that causes dysfunction of cellular RNA processing contributes to the pathogenesis of HD.
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Affiliation(s)
- Ya-Jun Jiang
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Mei-Xia Che
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Jin-Qiao Yuan
- the NMR Laboratory, National Center of Biomedical Analysis, 27 Taiping Road, Beijing 100850, China
| | - Yuan-Yuan Xie
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Xian-Zhong Yan
- the NMR Laboratory, National Center of Biomedical Analysis, 27 Taiping Road, Beijing 100850, China
| | - Hong-Yu Hu
- From the State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
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309
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Huang K, Sanders SS, Kang R, Carroll JB, Sutton L, Wan J, Singaraja R, Young FB, Liu L, El-Husseini A, Davis NG, Hayden MR. Wild-type HTT modulates the enzymatic activity of the neuronal palmitoyl transferase HIP14. Hum Mol Genet 2011; 20:3356-65. [PMID: 21636527 DOI: 10.1093/hmg/ddr242] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Huntington disease (HD) is caused by polyglutamine expansion in the huntingtin (HTT) protein. Huntingtin-interacting protein 14 (HIP14), one of 23 DHHC domain-containing palmitoyl acyl transferases (PATs), binds to HTT and robustly palmitoylates HTT at cysteine 214. Mutant HTT exhibits reduced palmitoylation and interaction with HIP14, contributing to the neuronal dysfunction associated with HD. In this study, we confirmed that, among 23 DHHC PATs, HIP14 and its homolog DHHC-13 (HIP14L) are the two major PATs that palmitoylate HTT. Wild-type HTT, in addition to serving as a palmitoylation substrate, also modulates the palmitoylation of HIP14 itself. In vivo, HIP14 palmitoylation is decreased in the brains of mice lacking one HTT allele (hdh+/-) and is further reduced in mouse cortical neurons treated with HTT antisense oligos (HTT-ASO) that knockdown HTT expression by ∼95%. Previously, it has been shown that palmitoylation of DHHC proteins may affect their enzymatic activity. Indeed, palmitoylation of SNAP25 by HIP14 is potentiated in vitro in the presence of wild-type HTT. This influence of HTT on HIP14 activity is lost in the presence of CAG expansion. Furthermore, in both brains of hdh+/- mice and neurons treated with HTT-ASO, we observe a significant reduction in palmitoylation of endogenous SNAP25 and GluR1, synaptic proteins that are substrates of HIP14, suggesting wild-type HTT also influences HIP14 enzymatic activity in vivo. This study describes an important biochemical function for wild-type HTT modulation of HIP14 palmitoylation and its enzymatic activity.
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Affiliation(s)
- Kun Huang
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada V5Z 4H4
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310
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Williams RH, Morton AJ, Burdakov D. Paradoxical function of orexin/hypocretin circuits in a mouse model of Huntington's disease. Neurobiol Dis 2011; 42:438-45. [PMID: 21324360 PMCID: PMC5767114 DOI: 10.1016/j.nbd.2011.02.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 02/04/2011] [Accepted: 02/07/2011] [Indexed: 10/18/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder involving progressive motor disturbances, cognitive decline, and desynchronized sleep-wake rhythms. Recent studies revealed that restoring normal sleep-wake cycles can improve cognitive function in HD mice, suggesting that some sleep/wake systems remain operational and thus represent potential therapeutic targets for HD. Hypothalamic neurons expressing orexins/hypocretins (orexin neurons) are fundamental orchestrators of arousal in mammals, but it is unclear whether orexin circuits operate normally in HD. Here we analyzed the electrophysiology, histology, and gene expression of orexin circuits in brain slices from R6/2 mice, a transgenic model of HD with a progressive neurological phenotype. We report that in R6/2 mice, the size of an electrically distinct subpopulation of orexin neurons is reduced, as is the number of orexin-immunopositive cells in some hypothalamic regions. R6/2 orexin cells display altered glutamatergic inputs, and have an abnormal circadian profile of activity, despite normal circadian rhythmicity of the suprachiasmatic nucleus (SCN), the "master clock" of the brain. Nevertheless, even at advanced stages of HD, intrinsic firing properties of orexin cells remain normal and suppressible by serotonin, noradrenaline, and glucose. Furthermore, histaminergic neurons (key cells required for the propagation of orexin-induced arousal) also display normal responses to orexin. Together, these data suggest that the orexin system remains functional and modifiable in HD mice, although its circadian activity profile is disrupted and no longer follows that of the SCN.
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Affiliation(s)
- Rhîannan H. Williams
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - A. Jennifer Morton
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Denis Burdakov
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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311
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Myre MA, Lumsden AL, Thompson MN, Wasco W, MacDonald ME, Gusella JF. Deficiency of huntingtin has pleiotropic effects in the social amoeba Dictyostelium discoideum. PLoS Genet 2011; 7:e1002052. [PMID: 21552328 PMCID: PMC3084204 DOI: 10.1371/journal.pgen.1002052] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 03/02/2011] [Indexed: 11/24/2022] Open
Abstract
Huntingtin is a large HEAT repeat protein first identified in humans, where a polyglutamine tract expansion near the amino terminus causes a gain-of-function mechanism that leads to selective neuronal loss in Huntington's disease (HD). Genetic evidence in humans and knock-in mouse models suggests that this gain-of-function involves an increase or deregulation of some aspect of huntingtin's normal function(s), which remains poorly understood. As huntingtin shows evolutionary conservation, a powerful approach to discovering its normal biochemical role(s) is to study the effects caused by its deficiency in a model organism with a short life-cycle that comprises both cellular and multicellular developmental stages. To facilitate studies aimed at detailed knowledge of huntingtin's normal function(s), we generated a null mutant of hd, the HD ortholog in Dictyostelium discoideum. Dictyostelium cells lacking endogenous huntingtin were viable but during development did not exhibit the typical polarized morphology of Dictyostelium cells, streamed poorly to form aggregates by accretion rather than chemotaxis, showed disorganized F-actin staining, exhibited extreme sensitivity to hypoosmotic stress, and failed to form EDTA-resistant cell–cell contacts. Surprisingly, chemotactic streaming could be rescued in the presence of the bivalent cations Ca2+ or Mg2+ but not pulses of cAMP. Although hd− cells completed development, it was delayed and proceeded asynchronously, producing small fruiting bodies with round, defective spores that germinated spontaneously within a glassy sorus. When developed as chimeras with wild-type cells, hd− cells failed to populate the pre-spore region of the slug. In Dictyostelium, huntingtin deficiency is compatible with survival of the organism but renders cells sensitive to low osmolarity, which produces pleiotropic cell autonomous defects that affect cAMP signaling and as a consequence development. Thus, Dictyostelium provides a novel haploid organism model for genetic, cell biological, and biochemical studies to delineate the functions of the HD protein. Genetic evidence in humans and mouse models of Huntington's disease suggests that the disease mutation confers a deleterious gain-of-function on huntingtin that acts through the deregulation of some aspect of the protein's normal function(s). While huntingtin's function is poorly understood, its evolutionary conservation makes investigation of its physiological role in lower organisms an attractive route that has yet to be fully exploited. Therefore, we have used Dictyostelium discoideum to study the consequences of huntingtin (hd) deficiency. Developing Dictyostelium cells chemotax to form a multicellular slug that forms a fruiting body, comprising dormant spores encased above dead stalk cells. We found that hd− cells were hypersensitive to hypoosmotic stress. When starved, hd− cells aggregate by accretion, showed disorganized F-actin, and failed to form EDTA-resistant cell–cell contacts. Surprisingly, chemotactic signaling was rescued with Ca2+ or Mg2+ but not pulses of cAMP. Development of hd− mutants produced small fruiting bodies with round, defective spores, and when mixed with wild-type cells they didn't differentiate into spores. Our results are consistent with mammalian studies that show huntingtin is a multifunctional protein involved in many biochemical processes; and, importantly, they establish Dictyostelium as a valuable experimental organism for exploring in biochemical detail huntingtin's normal function(s).
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Affiliation(s)
- Michael A. Myre
- Molecular Neurogenetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- * E-mail:
| | - Amanda L. Lumsden
- Molecular Neurogenetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Morgan N. Thompson
- Molecular Neurogenetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Wilma Wasco
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Marcy E. MacDonald
- Molecular Neurogenetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - James F. Gusella
- Molecular Neurogenetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
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312
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Kraft AD, Kaltenbach LS, Lo DC, Harry GJ. Activated microglia proliferate at neurites of mutant huntingtin-expressing neurons. Neurobiol Aging 2011; 33:621.e17-33. [PMID: 21482444 DOI: 10.1016/j.neurobiolaging.2011.02.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 02/01/2011] [Accepted: 02/16/2011] [Indexed: 01/13/2023]
Abstract
In Huntington's disease (HD), mutated huntingtin (mhtt) causes striatal neurodegeneration which is paralleled by elevated microglia cell numbers. In vitro corticostriatal slice and primary neuronal culture models, in which neuronal expression of mhtt fragments drives HD-like neurotoxicity, were employed to examine wild type microglia during both the initiation and progression of neuronal pathology. As neuronal pathology progressed, microglia initially localized in the vicinity of neurons expressing mhtt fragments increased in number, demonstrated morphological evidence of activation, and expressed the proliferation marker, Ki67. These microglia were positioned along irregular neurites, but did not localize with mhtt inclusions nor exacerbate mhtt fragment-induced neurotoxicity. Prior to neuronal pathology, microglia upregulated ionized calcium binding adaptor molecule 1 (Iba1), signaling a functional shift. With neurodegeneration, interleukin-6 and complement component 1q were increased. The results suggest a stimulatory, proliferative signal for microglia present at the onset of mhtt fragment-induced neurodegeneration. Thus, microglia effect a localized inflammatory response to neuronal mhtt expression that may serve to direct microglial removal of dysfunctional neurites or aberrant synapses, as is required for reparative actions in vivo.
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Affiliation(s)
- Andrew D Kraft
- Neurotoxicology Group, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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313
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Zündorf G, Reiser G. Calcium dysregulation and homeostasis of neural calcium in the molecular mechanisms of neurodegenerative diseases provide multiple targets for neuroprotection. Antioxid Redox Signal 2011; 14:1275-88. [PMID: 20615073 PMCID: PMC3122891 DOI: 10.1089/ars.2010.3359] [Citation(s) in RCA: 280] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The intracellular free calcium concentration subserves complex signaling roles in brain. Calcium cations (Ca(2+)) regulate neuronal plasticity underlying learning and memory and neuronal survival. Homo- and heterocellular control of Ca(2+) homeostasis supports brain physiology maintaining neural integrity. Ca(2+) fluxes across the plasma membrane and between intracellular organelles and compartments integrate diverse cellular functions. A vast array of checkpoints controls Ca(2+), like G protein-coupled receptors, ion channels, Ca(2+) binding proteins, transcriptional networks, and ion exchangers, in both the plasma membrane and the membranes of mitochondria and endoplasmic reticulum. Interactions between Ca(2+) and reactive oxygen species signaling coordinate signaling, which can be either beneficial or detrimental. In neurodegenerative disorders, cellular Ca(2+)-regulating systems are compromised. Oxidative stress, perturbed energy metabolism, and alterations of disease-related proteins result in Ca(2+)-dependent synaptic dysfunction, impaired plasticity, and neuronal demise. We review Ca(2+) control processes relevant for physiological and pathophysiological conditions in brain tissue. Dysregulation of Ca(2+) is decisive for brain cell death and degeneration after ischemic stroke, long-term neurodegeneration in Alzheimer's disease, Parkinson's disease, Huntington's disease, inflammatory processes, such as in multiple sclerosis, epileptic sclerosis, and leucodystrophies. Understanding the underlying molecular processes is of critical importance for the development of novel therapeutic strategies to prevent neurodegeneration and confer neuroprotection.
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Affiliation(s)
- Gregor Zündorf
- Institut für Neurobiochemie, Medizinische Fakultät der Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany
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314
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Reinhart PH, Kaltenbach LS, Essrich C, Dunn DE, Eudailey JA, DeMarco CT, Turmel GJ, Whaley JC, Wood A, Cho S, Lo DC. Identification of anti-inflammatory targets for Huntington's disease using a brain slice-based screening assay. Neurobiol Dis 2011; 43:248-56. [PMID: 21458569 DOI: 10.1016/j.nbd.2011.03.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 02/02/2011] [Accepted: 03/23/2011] [Indexed: 10/18/2022] Open
Abstract
Huntington's disease (HD) is a late-onset, neurodegenerative disease for which there are currently no cures nor disease-modifying treatments. Here we report the identification of several potential anti-inflammatory targets for HD using an ex vivo model of HD that involves the acute transfection of human mutant huntingtin-based constructs into rat brain slices. This model recapitulates key components of the human disease, including the formation of intracellular huntingtin protein (HTT)-containing inclusions and the progressive neurodegeneration of striatal neurons-both occurring within the native tissue context of these neurons. Using this "high-throughput biology" screening platform, we conducted a hypothesis-neutral screen of a collection of drug-like compounds which identified several anti-inflammatory targets that provided neuroprotection against HTT fragment-induced neurodegeneration. The nature of these targets provide further support for non-cell autonomous mechanisms mediating significant aspects of neuropathogenesis induced by mutant HTT fragment proteins.
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Affiliation(s)
- Peter H Reinhart
- Discovery Neuroscience, Wyeth Research, Princeton, NJ 08543, USA
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315
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Abstract
Huntington disease (HD) is an autosomal dominant neurodegenerative disease with complete penetrance. Although the understanding of the cellular mechanisms that drive neurodegeneration in HD and account for the characteristic pattern of neuronal vulnerability is incomplete, defects in energy metabolism, particularly mitochondrial function, represent a common thread in studies of HD pathogenesis in humans and animal models. Here we review the clinical, biochemical, and molecular evidence of an energy deficit in HD and discuss the mechanisms underlying mitochondrial and related alterations.
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Affiliation(s)
- Fanny Mochel
- INSERM UMR S975, Institut du Cerveau et de la Moelle,
AP-HP, Département de Génétique, and
Unité Fonctionnelle Neurométabolique, Hôpital La Salpêtrière, Paris, France.
Université Pierre et Marie Curie, Paris, France.
Department of Neurology, University of Texas Southwestern Medical Center and VA North Texas Medical Center, Dallas, Texas, USA.
Neuromuscular Center, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas, USA
| | - Ronald G. Haller
- INSERM UMR S975, Institut du Cerveau et de la Moelle,
AP-HP, Département de Génétique, and
Unité Fonctionnelle Neurométabolique, Hôpital La Salpêtrière, Paris, France.
Université Pierre et Marie Curie, Paris, France.
Department of Neurology, University of Texas Southwestern Medical Center and VA North Texas Medical Center, Dallas, Texas, USA.
Neuromuscular Center, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas, USA
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316
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Matus S, Glimcher LH, Hetz C. Protein folding stress in neurodegenerative diseases: a glimpse into the ER. Curr Opin Cell Biol 2011; 23:239-52. [PMID: 21288706 DOI: 10.1016/j.ceb.2011.01.003] [Citation(s) in RCA: 177] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/05/2011] [Accepted: 01/11/2011] [Indexed: 01/19/2023]
Abstract
Several neurodegenerative diseases share common neuropathology, primarily featuring the presence in the brain of abnormal protein inclusions containing specific misfolded proteins. Recent evidence indicates that alteration in organelle function is a common pathological feature of protein misfolding disorders, highlighting perturbations in the homeostasis of the endoplasmic reticulum (ER). Signs of ER stress have been detected in most experimental models of neurological disorders and more recently in brain samples from human patients with neurodegenerative disease. To cope with ER stress, cells activate an integrated signaling response termed the unfolded protein response (UPR), which aims to reestablish homeostasis in part through regulation of genes involved in protein folding, quality control and degradation pathways. Here we discuss the particular mechanisms currently proposed to be involved in the generation of protein folding stress in different neurodegenerative conditions and speculate about possible therapeutic interventions.
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Affiliation(s)
- Soledad Matus
- Center for Molecular Studies of Cell, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
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317
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Abstract
Huntington's disease is a progressive, fatal, neurodegenerative disorder caused by an expanded CAG repeat in the huntingtin gene, which encodes an abnormally long polyglutamine repeat in the huntingtin protein. Huntington's disease has served as a model for the study of other more common neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. These disorders all share features including: delayed onset; selective neuronal vulnerability, despite widespread expression of disease-related proteins during the whole lifetime; abnormal protein processing and aggregation; and cellular toxic effects involving both cell autonomous and cell-cell interaction mechanisms. Pathogenic pathways of Huntington's disease are beginning to be unravelled, offering targets for treatments. Additionally, predictive genetic testing and findings of neuroimaging studies show that, as in some other neurodegenerative disorders, neurodegeneration in affected individuals begins many years before onset of diagnosable signs and symptoms of Huntington's disease, and it is accompanied by subtle cognitive, motor, and psychiatric changes (so-called prodromal disease). Thus, Huntington's disease is also emerging as a model for strategies to develop therapeutic interventions, not only to slow progression of manifest disease but also to delay, or ideally prevent, its onset.
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Affiliation(s)
- Christopher A Ross
- Departments of Psychiatry, Neurology, Pharmacology, and Neuroscience, and Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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318
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Reiner A, Dragatsis I, Dietrich P. Genetics and neuropathology of Huntington's disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 98:325-72. [PMID: 21907094 PMCID: PMC4458347 DOI: 10.1016/b978-0-12-381328-2.00014-6] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder that prominently affects the basal ganglia, leading to affective, cognitive, behavioral and motor decline. The basis of HD is a CAG repeat expansion to >35 CAG in a gene that codes for a ubiquitous protein known as huntingtin, resulting in an expanded N-terminal polyglutamine tract. The size of the expansion is correlated with disease severity, with increasing CAG accelerating the age of onset. A variety of possibilities have been proposed as to the mechanism by which the mutation causes preferential injury to the basal ganglia. The present chapter provides a basic overview of the genetics and pathology of HD.
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Affiliation(s)
- Anton Reiner
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, 855 Monroe Ave. Memphis, TN 38163, USA
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319
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Nopoulos PC, Aylward EH, Ross CA, Mills JA, Langbehn DR, Johnson HJ, Magnotta VA, Pierson RK, Beglinger LJ, Nance MA, Barker RA, Paulsen JS. Smaller intracranial volume in prodromal Huntington's disease: evidence for abnormal neurodevelopment. Brain 2011; 134:137-42. [PMID: 20923788 PMCID: PMC3025719 DOI: 10.1093/brain/awq280] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/12/2010] [Accepted: 08/12/2010] [Indexed: 12/14/2022] Open
Abstract
Huntington's disease is an autosomal dominant brain disease. Although conceptualized as a neurodegenerative disease of the striatum, a growing number of studies challenge this classic concept of Huntington's disease aetiology. Intracranial volume is the tissue and fluid within the calvarium and is a representation of the maximal brain growth obtained during development. The current study reports intracranial volume obtained from an magnetic resonance imaging brain scan in a sample of subjects (n = 707) who have undergone presymptomatic gene testing. Participants who are gene-expanded but not yet manifesting the disease (prodromal Huntington's disease) are compared with subjects who are non-gene expanded. The prodromal males had significantly smaller intracranial volume measures with a mean volume that was 4% lower compared with controls. Although the prodromal females had smaller intracranial volume measures compared with their controls, this was not significant. The current findings suggest that mutant huntingtin can cause abnormal development, which may contribute to the pathogenesis of Huntington's disease.
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Affiliation(s)
- Peggy C. Nopoulos
- 1 Department of Psychiatry, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa, IA 52242, USA
- 2 Department of Pediatrics, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa City, IA 52242, USA
- 3 Department of Neurology, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa City, IA 52242, USA
| | | | - Christopher A. Ross
- 5 Division of Neurology, Pharmacology and Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - James A. Mills
- 1 Department of Psychiatry, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa, IA 52242, USA
| | - Douglas R. Langbehn
- 1 Department of Psychiatry, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa, IA 52242, USA
| | - Hans J. Johnson
- 1 Department of Psychiatry, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa, IA 52242, USA
| | - Vincent A. Magnotta
- 1 Department of Psychiatry, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa, IA 52242, USA
- 6 Department of Radiology, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa City, IA 52242, USA
| | - Ronald K. Pierson
- 1 Department of Psychiatry, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa, IA 52242, USA
| | - Leigh J. Beglinger
- 1 Department of Psychiatry, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa, IA 52242, USA
| | - Martha A. Nance
- 7 Hennepin County Medical Center, Department of Neurosciences, Saint Louis Park, MN, USA
| | - Roger A. Barker
- 8 Cambridge Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
| | - Jane S. Paulsen
- 1 Department of Psychiatry, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa, IA 52242, USA
- 3 Department of Neurology, The University of Iowa Roy and Lucille Carver College of Medicine, Iowa City, IA 52242, USA
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320
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Huntington's disease: clinical presentation and treatment. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 98:297-323. [PMID: 21907093 DOI: 10.1016/b978-0-12-381328-2.00013-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Huntington's disease (HD) is a devastating inherited neurodegenerative disease characterized primarily by progressive motor, cognitive, and psychiatric symptoms. It is caused by autosomal dominant inheritance of an expanded CAG repeat within the Huntington's gene on chromosome 4. In this chapter, we characterize the typical and variant motor phenotypes of the disease and then proceed to describe the cognitive and psychiatric profile. We then give an overview of a suggested multidisciplinary approach to the management of HD, emphasizing the fact that it is a disease which impacts on entire families rather than affecting individuals in isolation. We then describe the pharmacological and nonpharmacological options available for management of specific symptoms.
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321
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Soldati C, Bithell A, Conforti P, Cattaneo E, Buckley NJ. Rescue of gene expression by modified REST decoy oligonucleotides in a cellular model of Huntington's disease. J Neurochem 2010; 116:415-25. [PMID: 21105876 DOI: 10.1111/j.1471-4159.2010.07122.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Transcriptional dysfunction is a prominent hallmark of Huntington's disease (HD). Several transcription factors have been implicated in the aetiology of HD progression and one of the most prominent is repressor element 1 (RE1) silencing transcription factor (REST). REST is a global repressor of neuronal gene expression and in the presence of mutant Huntingtin increased nuclear REST levels lead to elevated RE1 occupancy and a concomitant increase in target gene repression, including brain-derived neurotrophic factor. It is of great interest to devise strategies to reverse transcriptional dysregulation caused by increased nuclear REST and determine the consequences in HD. Thus far, such strategies have involved RNAi or mutant REST constructs. Decoys are double-stranded oligodeoxynucleotides corresponding to the DNA-binding element of a transcription factor and act to sequester it, thereby abrogating its transcriptional activity. Here, we report the use of a novel decoy strategy to rescue REST target gene expression in a cellular model of HD. We show that delivery of the decoy in cells expressing mutant Huntingtin leads to its specific interaction with REST, a reduction in REST occupancy of RE1s and rescue of target gene expression, including Bdnf. These data point to an alternative strategy for rebalancing the transcriptional dysregulation in HD.
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Affiliation(s)
- Chiara Soldati
- Department of Neuroscience and Centre for the Cellular Basis of Behaviour, Institute of Psychiatry, King's College London, The James Black Centre, London, UK
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322
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Klempíř J, Zidovská J, Stochl J, Ing VK, Uhrová T, Roth J. The number of CAG repeats within the normal allele does not influence the age of onset in Huntington's disease. Mov Disord 2010; 26:125-9. [PMID: 21322024 DOI: 10.1002/mds.23436] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 06/24/2010] [Accepted: 08/11/2010] [Indexed: 11/07/2022] Open
Abstract
Huntington's disease (HD) is caused by the expansion of the number of CAG repeats on the chromosome 4p16.3, which results in elongated glutamine tract of huntingtin. The purpose of this work was to examine the interaction between the normal and mutant alleles of this gene and their effect on the clinical onset of HD. We hypothesized that in patients with identical number of CAG repeats within the mutant allele, the age of onset of HD is influenced by the number of CAG repeats within the normal allele. We analyzed the relations between the number of CAG repeats within the normal and mutant alleles, the age at HD onset, and the character of initial symptoms in 468 patients with clinically expressed HD. Although the Cox regression coefficient of 0.15 was significant (P < 0.0001), the regression model explained only 28% of the variance of the age at onset related to the effect of the number of CAG repeats within normal allele. Within the groups of patients with the same number of CAG repeats of the mutant allele, number of CAG repeats of the normal allele was found uncorrelated to the age at onset. Furthermore, when analyzing subgroups of patients with the same allelic composition on both alleles, we failed to observe any correlation with the age at the onset. Our analysis gives no corroboration to the idea of a normal allele having a share in the modification of the age at HD onset. We believe that with the current state of knowledge it is not possible to devise a mathematical model for HD onset prediction because too many entirely unknown modifying factors are still involved.
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Affiliation(s)
- Jiří Klempíř
- Department of Neurology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic.
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323
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Krobitsch S, Kazantsev AG. Huntington's disease: From molecular basis to therapeutic advances. Int J Biochem Cell Biol 2010; 43:20-4. [PMID: 21056115 DOI: 10.1016/j.biocel.2010.10.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 10/26/2010] [Accepted: 10/27/2010] [Indexed: 12/15/2022]
Abstract
Huntington's disease is an autosomal dominant genetic neurodegenerative disorder, which is characterized by progressive motor dysfunction, emotional disturbances, dementia, and weight loss. The disease is caused by pathological CAG-triplet repeat extension(s), encoding polyglutamines, within the gene product, huntingtin. Huntingtin is ubiquitously expressed through the body and is a protein of uncertain molecular function(s). Mutant huntingtin, containing pathologically extended polyglutamines causes the earliest and most dramatic neuropathologic changes in the neostriatum and cerebral cortex. Extended polyglutamines confer structural conformational changes to huntingtin, which gains novel properties, resulting in aberrant interactions with multiple cellular components. The diverse and variable aberrations mediated by mutant huntingtin perturb many cellular functions essential for neuronal homeostasis and underlie pleiotropic mechanisms of Huntington's disease pathogenesis. The only approved drug for Huntington's disease is a symptomatic treatment, tetrabenazine; thus, novel neuroprotective strategies, slowing, blocking and possibly reversing disease progression, are vital for developing effective therapies.
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Affiliation(s)
- Sylvia Krobitsch
- Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany.
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324
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Mastroberardino PG, Piacentini M. Type 2 transglutaminase in Huntington's disease: a double-edged sword with clinical potential. J Intern Med 2010; 268:419-31. [PMID: 20964734 PMCID: PMC3073231 DOI: 10.1111/j.1365-2796.2010.02275.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Huntington's disease (HD) is a dominant genetic neurodegenerative disorder. The pathology affects principally neurons in the basal ganglia circuits and terminates invariably in death. There is compelling necessity for safe and effective therapeutic strategies to arrest, or even retard the progression of the pathogenesis. Recent findings indicate the autophagy-lysosome systems as appealing targets for pharmacological intervention. Autophagy exerts a critical role in controlling neuronal protein homeostasis, which is perturbed in HD, and is compromised in the pathogenesis of several neurodegenerative diseases. Type 2 transglutaminase (TG2) plays an important role both in apoptosis and autophagy regulation, and accumulates at high levels in cells under stressful conditions. TG2 inhibition, achieved either via drug treatments or genetic approaches, has been shown to be beneficial for the treatment of HD in animal models. In this review we will discuss the relevance of TG2 to the pathogenesis of HD, in an effort to define novel therapeutic avenues.
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325
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Daigeler A, Chromik AM, Haendschke K, Emmelmann S, Siepmann M, Hensel K, Schmitz G, Klein-Hitpass L, Steinau HU, Lehnhardt M, Hauser J. Synergistic effects of sonoporation and taurolidin/TRAIL on apoptosis in human fibrosarcoma. ULTRASOUND IN MEDICINE & BIOLOGY 2010; 36:1893-1906. [PMID: 20870344 DOI: 10.1016/j.ultrasmedbio.2010.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 07/30/2010] [Accepted: 08/13/2010] [Indexed: 05/29/2023]
Abstract
Sonodynamic therapy, in combination with ultrasound contrast agents, proved to enhance the uptake of chemotherapeutics in malignant cells. HT1080 fibrosarcoma cells were treated in vitro with a combination of ultrasound SonoVue™-microbubbles and taurolidine (TRD) plus tumor necrosis factor related apoptosis inducing ligand (TRAIL). Apoptosis was measured by TdT-mediated dUTP-biotin nick end labelling (TUNEL) assay and fluorescence activated cell sorting (FACS) analysis. Gene expression was analysed by RNA-microarray. The apoptotic effects of TRD and TRAIL on human fibrosarcoma are enhanced by sonodynamic therapy and additional application of contrast agents, such as SonoVue™ by 25%. A broad change in the expression of genes related to apoptotic pathways is observed when ultrasound and microbubbles act synchronously in combination with the chemotherapeutics (e.g. BIRC3, NFKBIA and TNFAIP3). Some of these genes have already been proven to play a role in programmed cell death in human fibrosarcoma (HSPA1A/HSPA1B, APAF1, PAWR, SOCS2) or were associated with sonication induced apoptosis (CD44). Further studies are needed to explore the options of sonodynamic therapy on soft tissue sarcoma and its molecular mechanisms.
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Affiliation(s)
- Adrien Daigeler
- Department of Hand, Plastic and Reconstructive Surgery, Burn Center, BG-Unfallkrankenhaus, Ludwigshafen, Germany.
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326
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Blázquez C, Chiarlone A, Sagredo O, Aguado T, Pazos MR, Resel E, Palazuelos J, Julien B, Salazar M, Börner C, Benito C, Carrasco C, Diez-Zaera M, Paoletti P, Díaz-Hernández M, Ruiz C, Sendtner M, Lucas JJ, de Yébenes JG, Marsicano G, Monory K, Lutz B, Romero J, Alberch J, Ginés S, Kraus J, Fernández-Ruiz J, Galve-Roperh I, Guzmán M. Loss of striatal type 1 cannabinoid receptors is a key pathogenic factor in Huntington's disease. ACTA ACUST UNITED AC 2010; 134:119-36. [PMID: 20929960 DOI: 10.1093/brain/awq278] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Endocannabinoids act as neuromodulatory and neuroprotective cues by engaging type 1 cannabinoid receptors. These receptors are highly abundant in the basal ganglia and play a pivotal role in the control of motor behaviour. An early downregulation of type 1 cannabinoid receptors has been documented in the basal ganglia of patients with Huntington's disease and animal models. However, the pathophysiological impact of this loss of receptors in Huntington's disease is as yet unknown. Here, we generated a double-mutant mouse model that expresses human mutant huntingtin exon 1 in a type 1 cannabinoid receptor-null background, and found that receptor deletion aggravates the symptoms, neuropathology and molecular pathology of the disease. Moreover, pharmacological administration of the cannabinoid Δ(9)-tetrahydrocannabinol to mice expressing human mutant huntingtin exon 1 exerted a therapeutic effect and ameliorated those parameters. Experiments conducted in striatal cells show that the mutant huntingtin-dependent downregulation of the receptors involves the control of the type 1 cannabinoid receptor gene promoter by repressor element 1 silencing transcription factor and sensitizes cells to excitotoxic damage. We also provide in vitro and in vivo evidence that supports type 1 cannabinoid receptor control of striatal brain-derived neurotrophic factor expression and the decrease in brain-derived neurotrophic factor levels concomitant with type 1 cannabinoid receptor loss, which may contribute significantly to striatal damage in Huntington's disease. Altogether, these results support the notion that downregulation of type 1 cannabinoid receptors is a key pathogenic event in Huntington's disease, and suggest that activation of these receptors in patients with Huntington's disease may attenuate disease progression.
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Affiliation(s)
- Cristina Blázquez
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Huntington’s Disease and Ataxias Collaborative Project, 28040 Madrid, Spain
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327
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Cheng A, Hou Y, Mattson MP. Mitochondria and neuroplasticity. ASN Neuro 2010; 2:e00045. [PMID: 20957078 PMCID: PMC2949087 DOI: 10.1042/an20100019] [Citation(s) in RCA: 295] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 08/06/2010] [Accepted: 08/13/2010] [Indexed: 12/22/2022] Open
Abstract
The production of neurons from neural progenitor cells, the growth of axons and dendrites and the formation and reorganization of synapses are examples of neuroplasticity. These processes are regulated by cell-autonomous and intercellular (paracrine and endocrine) programs that mediate responses of neural cells to environmental input. Mitochondria are highly mobile and move within and between subcellular compartments involved in neuroplasticity (synaptic terminals, dendrites, cell body and the axon). By generating energy (ATP and NAD(+)), and regulating subcellular Ca(2+) and redox homoeostasis, mitochondria may play important roles in controlling fundamental processes in neuroplasticity, including neural differentiation, neurite outgrowth, neurotransmitter release and dendritic remodelling. Particularly intriguing is emerging data suggesting that mitochondria emit molecular signals (e.g. reactive oxygen species, proteins and lipid mediators) that can act locally or travel to distant targets including the nucleus. Disturbances in mitochondrial functions and signalling may play roles in impaired neuroplasticity and neuronal degeneration in Alzheimer's disease, Parkinson's disease, psychiatric disorders and stroke.
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Key Words
- AD, Alzheimer's disease
- AP, adaptor protein
- APP, amyloid precursor protein
- Aβ, amyloid β-peptide
- BDNF, brain-derived neurotrophic factor
- CR, caloric restriction
- CREB, cAMP-response-element-binding protein
- CaMK, Ca2+/calmodulin-dependent protein kinase
- ES, embryonic stem
- ETC, electron transport chain
- HD, Huntington's disease
- LRRK2, leucine-rich repeat kinase 2
- LTP, long-term potentiation
- MAPK, mitogen-activated protein kinase
- Mn-SOD, manganese superoxide dismutase
- NGF, nerve growth factor
- NMDA, N-methyl-d-aspartate
- Nrf1, nuclear respiratory factor 1
- OPA1, Optic Atrophy-1
- PD, Parkinson's disease
- PGC1α, peroxisome-proliferator-activated receptor γ co-activator 1α
- PINK1, PTEN (phosphatase and tensin homologue deleted on chromosome 10)-induced kinase 1
- PPAR, peroxisome-proliferator-activated receptor
- UCP, uncoupling protein
- mitochondria biogenesis
- mitochondria fission and fusion
- neural progenitor cell
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Affiliation(s)
- Aiwu Cheng
- *Laboratory of Neurosciences, National Institute of Aging Intramural Research Program, Baltimore, MD 21224, U.S.A
| | - Yan Hou
- *Laboratory of Neurosciences, National Institute of Aging Intramural Research Program, Baltimore, MD 21224, U.S.A
| | - Mark P Mattson
- *Laboratory of Neurosciences, National Institute of Aging Intramural Research Program, Baltimore, MD 21224, U.S.A
- †Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, U.S.A
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328
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Hands SL, Wyttenbach A. Neurotoxic protein oligomerisation associated with polyglutamine diseases. Acta Neuropathol 2010; 120:419-37. [PMID: 20514488 DOI: 10.1007/s00401-010-0703-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 05/20/2010] [Accepted: 05/23/2010] [Indexed: 02/07/2023]
Abstract
Polyglutamine (polyQ) diseases are associated with a CAG/polyQ expansion mutation in unrelated proteins. Upon elongation of the glutamine tract, disease proteins aggregate within cells, mainly in the central nervous system (CNS) and this aggregation process is associated with neurotoxicity. However, it remains unclear to what extent and how this aggregation causes neuronal dysfunction in the CNS. Aiming at preventing neuronal dysfunction, it will be crucial to determine the links between aggregation and cellular dysfunction, understand the folding pathway of polyQ proteins and discover the relative neurotoxicity of polyQ protein species formed along the aggregation pathway. Here, we review what is known about conformations of polyQ peptides and proteins in their monomeric state from experimental and modelling data, how conformational changes of polyQ proteins relate to their oligomerisation and morphology of aggregates and which cellular function are impaired by oligomers, in vitro and in vivo. We also summarise the key modulatory cellular mechanisms and co-factors, which could affect the folding pathway and kinetics of polyQ aggregation. Although many studies have investigated the relationship between polyQ aggregation and toxicity, these have mainly focussed on investigating changes in the formation of the classical hallmark of polyQ diseases, i.e. microscopically visible inclusion bodies. However, recent studies in which oligomeric species have been considered start to shed light on the identity of neurotoxic oligomeric species. Initial evidence suggests that conformational changes induced by polyQ expansions and their surrounding sequence lead to the formation of particular oligomeric intermediates that may differentially affect neurotoxicity.
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Affiliation(s)
- Sarah L Hands
- Southampton Neuroscience Group, School of Biological Sciences, University of Southampton, Southampton SO16 7PX, UK
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329
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Gonzales E, Yin J. Drosophila Models of Huntington's Disease exhibit sleep abnormalities. PLOS CURRENTS 2010; 2:k/-/-/2as2tsd09zfs8/2. [PMID: 20890443 PMCID: PMC2947800 DOI: 10.1371/currents.rrn1185] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/29/2010] [Indexed: 11/18/2022]
Abstract
The complex pathology of neurodegenerative diseases presents a challenge to researchers who model the disease, and clinicians who treat patients. The identification of early, perhaps even prodromal, biomarkers is important for developing strategies to ameliorate disease progression. Sleep disturbances are a clinical feature of Huntington’s disease (HD) as well as a part of normal aging. Whether sleep dysfunctions in HD patients are epiphenomenal or central to the neurodegenerative disease process is unclear. We show that sleep fragmentation is shared among Drosophila transgenic models that express mutant forms of huntingtin (mHtt), and flies with RNAi-mediated knockdown of the endogenous gene (dhtt). Our data suggest that sleep disturbances in HD may represent loss of function in the endogenous dhtt gene and that sleep perturbations in Drosophila HD models present an opportunity for screening therapeutic interventions.
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330
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Huntingtin Is Required for Mitotic Spindle Orientation and Mammalian Neurogenesis. Neuron 2010; 67:392-406. [DOI: 10.1016/j.neuron.2010.06.027] [Citation(s) in RCA: 194] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2010] [Indexed: 01/06/2023]
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331
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Zuccato C, Valenza M, Cattaneo E. Molecular Mechanisms and Potential Therapeutical Targets in Huntington's Disease. Physiol Rev 2010; 90:905-81. [DOI: 10.1152/physrev.00041.2009] [Citation(s) in RCA: 626] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the gene encoding for huntingtin protein. A lot has been learned about this disease since its first description in 1872 and the identification of its causative gene and mutation in 1993. We now know that the disease is characterized by several molecular and cellular abnormalities whose precise timing and relative roles in pathogenesis have yet to be understood. HD is triggered by the mutant protein, and both gain-of-function (of the mutant protein) and loss-of-function (of the normal protein) mechanisms are involved. Here we review the data that describe the emergence of the ancient huntingtin gene and of the polyglutamine trait during the last 800 million years of evolution. We focus on the known functions of wild-type huntingtin that are fundamental for the survival and functioning of the brain neurons that predominantly degenerate in HD. We summarize data indicating how the loss of these beneficial activities reduces the ability of these neurons to survive. We also review the different mechanisms by which the mutation in huntingtin causes toxicity. This may arise both from cell-autonomous processes and dysfunction of neuronal circuitries. We then focus on novel therapeutical targets and pathways and on the attractive option to counteract HD at its primary source, i.e., by blocking the production of the mutant protein. Strategies and technologies used to screen for candidate HD biomarkers and their potential application are presented. Furthermore, we discuss the opportunities offered by intracerebral cell transplantation and the likely need for these multiple routes into therapies to converge at some point as, ideally, one would wish to stop the disease process and, at the same time, possibly replace the damaged neurons.
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Affiliation(s)
- Chiara Zuccato
- Department of Pharmacological Sciences and Centre for Stem Cell Research, Università degli Studi di Milano, Milan, Italy
| | - Marta Valenza
- Department of Pharmacological Sciences and Centre for Stem Cell Research, Università degli Studi di Milano, Milan, Italy
| | - Elena Cattaneo
- Department of Pharmacological Sciences and Centre for Stem Cell Research, Università degli Studi di Milano, Milan, Italy
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332
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Rivera-Mancía S, Pérez-Neri I, Ríos C, Tristán-López L, Rivera-Espinosa L, Montes S. The transition metals copper and iron in neurodegenerative diseases. Chem Biol Interact 2010; 186:184-99. [DOI: 10.1016/j.cbi.2010.04.010] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 01/22/2010] [Accepted: 04/08/2010] [Indexed: 12/14/2022]
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333
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Kaltenbach LS, Bolton MM, Shah B, Kanju PM, Lewis GM, Turmel GJ, Whaley JC, Trask OJ, Lo DC. Composite primary neuronal high-content screening assay for Huntington's disease incorporating non-cell-autonomous interactions. ACTA ACUST UNITED AC 2010; 15:806-19. [PMID: 20581077 DOI: 10.1177/1087057110373392] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Huntington's disease (HD) is a fatal neurodegenerative disease characterized by progressive cognitive, behavioral, and motor deficits and caused by expansion of a polyglutamine repeat in the Huntingtin protein (Htt). Despite its monogenic nature, HD pathogenesis includes obligatory non-cell-autonomous pathways involving both the cortex and the striatum, and therefore effective recapitulation of relevant HD disease pathways in cell lines and primary neuronal monocultures is intrinsically limited. To address this, the authors developed an automated high-content imaging screen in high-density primary cultures of cortical and striatal neurons together with supporting glial cells. Cortical and striatal neurons are transfected separately with different fluorescent protein markers such that image-based high-content analysis can be used to assay these neuronal populations separately but still supporting their intercellular interactions, including abundant synaptic interconnectivity. This assay was reduced to practice using transfection of a mutant N-terminal Htt domain and validated via a screen of ~400 selected small molecules. Both expected as well as novel candidate targets for HD emerged from this screen; of particular interest were target classes with close relative proximity to clinical testing. These findings suggest that composite primary cultures incorporating increased levels of biological complexity can be used for high-content imaging and "high-context" screening to represent molecular targets that otherwise may be operant only in the complex tissue environment found in vivo during disease pathogenesis.
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Affiliation(s)
- Linda S Kaltenbach
- Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, NC 27704, USA.
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334
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Neuroinflammation in Huntington's disease. J Neural Transm (Vienna) 2010; 117:1001-8. [PMID: 20535620 DOI: 10.1007/s00702-010-0430-7] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 05/22/2010] [Indexed: 01/17/2023]
Abstract
Huntington's disease (HD) is a monogenic neurodegenerative disease characterized by abnormal motor movements, personality changes and early death. In contrast to other neurodegenerative diseases, very little is known about the role of neuroinflammation in HD. While the current data clearly demonstrate the existence of inflammatory processes in HD pathophysiology, the question of whether neuroinflammation is purely reactive or might actively participate in disease pathogenesis is currently a matter of ongoing research and debate. This review will try to shed some light on the current state of research in this area and provide an outlook on potential future developments.
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335
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Pardo R, Molina-Calavita M, Poizat G, Keryer G, Humbert S, Saudou F. pARIS-htt: an optimised expression platform to study huntingtin reveals functional domains required for vesicular trafficking. Mol Brain 2010; 3:17. [PMID: 20515468 PMCID: PMC2887845 DOI: 10.1186/1756-6606-3-17] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 06/01/2010] [Indexed: 01/02/2023] Open
Abstract
Background Huntingtin (htt) is a multi-domain protein of 350 kDa that is mutated in Huntington's disease (HD) but whose function is yet to be fully understood. This absence of information is due in part to the difficulty of manipulating large DNA fragments by using conventional molecular cloning techniques. Consequently, few studies have addressed the cellular function(s) of full-length htt and its dysfunction(s) associated with the disease. Results We describe a flexible synthetic vector encoding full-length htt called pARIS-htt (Adaptable, RNAi Insensitive &Synthetic). It includes synthetic cDNA coding for full-length human htt modified so that: 1) it is improved for codon usage, 2) it is insensitive to four different siRNAs allowing gene replacement studies, 3) it contains unique restriction sites (URSs) dispersed throughout the entire sequence without modifying the translated amino acid sequence, 4) it contains multiple cloning sites at the N and C-ter ends and 5) it is Gateway compatible. These modifications facilitate mutagenesis, tagging and cloning into diverse expression plasmids. Htt regulates dynein/dynactin-dependent trafficking of vesicles, such as brain-derived neurotrophic factor (BDNF)-containing vesicles, and of organelles, including reforming and maintenance of the Golgi near the cell centre. We used tests of these trafficking functions to validate various pARIS-htt constructs. We demonstrated, after silencing of endogenous htt, that full-length htt expressed from pARIS-htt rescues Golgi apparatus reformation following reversible microtubule disruption. A mutant form of htt that contains a 100Q expansion and a htt form devoid of either HAP1 or dynein interaction domains are both unable to rescue loss of endogenous htt. These mutants have also an impaired capacity to promote BDNF vesicular trafficking in neuronal cells. Conclusion We report the validation of a synthetic gene encoding full-length htt protein that will facilitate analyses of its structure/function. This may help provide relevant information about the cellular dysfunctions operating during the disease. As proof of principle, we show that either polyQ expansion or deletion of key interacting domains within full-length htt protein impairs its function in transport indicating that HD mutation induces defects on intrinsic properties of the protein and further demonstrating the importance of studying htt in its full-length context.
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336
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Genetic zebrafish models of neurodegenerative diseases. Neurobiol Dis 2010; 40:58-65. [PMID: 20493258 DOI: 10.1016/j.nbd.2010.05.017] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 05/05/2010] [Accepted: 05/11/2010] [Indexed: 11/23/2022] Open
Abstract
As a consequence of the widespread use of zebrafish in developmental biology studies, an extensive array of experimental tools and techniques has been assembled; it has recently become apparent that these might be exploited in the analysis of human neurodegenerative diseases. A surprising degree of functional conservation has been demonstrated between human genes implicated in neurodegenerative diseases and their zebrafish orthologues. In zebrafish models of recessive parkinsonism, Parkin or Pink1 knockdown gave rise to specific loss of dopamine neurons; in a zebrafish model of recessive spinal muscular atrophy, loss of Smn1 function caused specific motor axonal defects. In addition, pathological features of several dominant diseases were replicated by transgenic over-expression of mutant human proteins, including Tau, Huntingtin, and SOD1. In some cases, conservation of relevant cellular pathways was sufficient that disease-specific posttranslational changes to the respective proteins were found in the zebrafish models. These data collectively suggest that the zebrafish can be an appropriate setting in which to model the molecular events underlying human neuropsychiatric disease. Consequently, novel findings yielded by studies in zebrafish models may be applicable to human diseases; this is an exciting prospect, in view of the many potential uses of zebrafish models, for example, screening for lead therapeutic compounds, rapid functional assessments of putative modifier genes, and live observation of pathogenic mechanisms in vivo.
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337
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Puerta E, Hervias I, Barros-Miñones L, Jordan J, Ricobaraza A, Cuadrado-Tejedor M, García-Osta A, Aguirre N. Sildenafil protects against 3-nitropropionic acid neurotoxicity through the modulation of calpain, CREB, and BDNF. Neurobiol Dis 2010; 38:237-45. [DOI: 10.1016/j.nbd.2010.01.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 12/24/2009] [Accepted: 01/17/2010] [Indexed: 11/26/2022] Open
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Brundin P, Melki R, Kopito R. Prion-like transmission of protein aggregates in neurodegenerative diseases. Nat Rev Mol Cell Biol 2010; 11:301-7. [PMID: 20308987 DOI: 10.1038/nrm2873] [Citation(s) in RCA: 542] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Neurodegenerative diseases are commonly associated with the accumulation of intracellular or extracellular protein aggregates. Recent studies suggest that these aggregates are capable of crossing cellular membranes and can directly contribute to the propagation of neurodegenerative disease pathogenesis. We propose that, once initiated, neuropathological changes might spread in a 'prion-like' manner and that disease progression is associated with the intercellular transfer of pathogenic proteins. The transfer of naked infectious particles between cells could therefore be a target for new disease-modifying therapies.
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Affiliation(s)
- Patrik Brundin
- Patrik Brundin is at the Neuronal Survival Unit, Wallenberg Neuroscience Center, Lund University, BMC A10, 221 84 Lund, Sweden.
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339
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Abu-Helo A, Simonin F. Identification and biological significance of G protein-coupled receptor associated sorting proteins (GASPs). Pharmacol Ther 2010; 126:244-50. [PMID: 20394773 DOI: 10.1016/j.pharmthera.2010.03.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 03/23/2010] [Indexed: 12/25/2022]
Abstract
G protein-coupled receptors (GPCRs) represent one of the most abundant protein families encoded by the human genome. They are involved in the modulation of numerous physiological functions and represent major drug targets. Their activity is tightly controlled by a vast array of interacting partners that modulate their membrane targeting, intracellular trafficking and signalling properties. Among them, several proteins from the same family, G protein-coupled receptor associated sorting proteins (GASP), have been shown to display a broad spectrum of interactions with GPCRs. In addition to their postulated role in the modulation of the post-endocytic sorting of these receptors, recent data indicate that several GASPs may modulate the transcriptional activity of the cell through their interaction with transcription factors. However, no clear molecular function has been assigned yet to this protein family. In this review, we describe the discovery of GASPs, their major features, interacting partners, functions and possible involvement in pathological situations including neurodegenerative diseases and cancer.
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Affiliation(s)
- Alaa Abu-Helo
- Institut de Recherche de l'ESBS, CNRS - Université de Strasbourg, FRE3211, Bld Sébastien Brant, 67412 Illkirch, France
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340
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Differential epigenetic regulation of BDNF and NT-3 genes by trichostatin A and 5-aza-2′-deoxycytidine in Neuro-2a cells. Biochem Biophys Res Commun 2010; 394:173-7. [DOI: 10.1016/j.bbrc.2010.02.139] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 02/22/2010] [Indexed: 11/21/2022]
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341
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Savas JN, Ma B, Deinhardt K, Culver BP, Restituito S, Wu L, Belasco JG, Chao MV, Tanese N. A role for huntington disease protein in dendritic RNA granules. J Biol Chem 2010; 285:13142-53. [PMID: 20185826 DOI: 10.1074/jbc.m110.114561] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulated transport and local translation of mRNA in neurons are critical for modulating synaptic strength, maintaining proper neural circuitry, and establishing long term memory. Neuronal RNA granules are ribonucleoprotein particles that serve to transport mRNA along microtubules and control local protein synthesis in response to synaptic activity. Studies suggest that neuronal RNA granules share similar structures and functions with somatic P-bodies. We recently reported that the Huntington disease protein huntingtin (Htt) associates with Argonaute (Ago) and localizes to cytoplasmic P-bodies, which serve as sites of mRNA storage, degradation, and small RNA-mediated gene silencing. Here we report that wild-type Htt associates with Ago2 and components of neuronal granules and co-traffics with mRNA in dendrites. Htt was found to co-localize with RNA containing the 3'-untranslated region sequence of known dendritically targeted mRNAs. Knockdown of Htt in neurons caused altered localization of mRNA. When tethered to a reporter construct, Htt down-regulated reporter gene expression in a manner dependent on Ago2, suggesting that Htt may function to repress translation of mRNAs during transport in neuronal granules.
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Affiliation(s)
- Jeffrey N Savas
- Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA
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342
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Deletion of the huntingtin polyglutamine stretch enhances neuronal autophagy and longevity in mice. PLoS Genet 2010; 6:e1000838. [PMID: 20140187 PMCID: PMC2816686 DOI: 10.1371/journal.pgen.1000838] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 01/04/2010] [Indexed: 01/07/2023] Open
Abstract
Expansion of a stretch of polyglutamine in huntingtin (htt), the protein product of the IT15 gene, causes Huntington's disease (HD). Previous investigations into the role of the polyglutamine stretch (polyQ) in htt function have suggested that its length may modulate a normal htt function involved in regulating energy homeostasis. Here we show that expression of full-length htt lacking its polyglutamine stretch (DeltaQ-htt) in a knockin mouse model for HD (Hdh(140Q/DeltaQ)), reduces significantly neuropil mutant htt aggregates, ameliorates motor/behavioral deficits, and extends lifespan in comparison to the HD model mice (Hdh(140Q/+)). The rescue of HD model phenotypes is accompanied by the normalization of lipofuscin levels in the brain and an increase in the steady-state levels of the mammalian autophagy marker microtubule-associate protein 1 light chain 3-II (LC3-II). We also find that DeltaQ-htt expression in vitro increases autophagosome synthesis and stimulates the Atg5-dependent clearance of truncated N-terminal htt aggregates. DeltaQ-htt's effect on autophagy most likely represents a gain-of-function, as overexpression of full-length wild-type htt in vitro does not increase autophagosome synthesis. Moreover, Hdh(DeltaQ/DeltaQ) mice live significantly longer than wild-type mice, suggesting that autophagy upregulation may be beneficial both in diseases caused by toxic intracellular aggregate-prone proteins and also as a lifespan extender in normal mammals.
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343
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Yang H, Liu C, Zhong Y, Luo S, Monteiro MJ, Fang S. Huntingtin interacts with the cue domain of gp78 and inhibits gp78 binding to ubiquitin and p97/VCP. PLoS One 2010; 5:e8905. [PMID: 20126661 PMCID: PMC2811200 DOI: 10.1371/journal.pone.0008905] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Accepted: 01/06/2010] [Indexed: 02/05/2023] Open
Abstract
Huntington's disease (HD) is caused by polyglutamine expansion in huntingtin (htt) protein, but the exact mechanism of HD pathogenesis remains uncertain. Recent evidence suggests that htt proteins with expanded polyglutamine tracts induce endoplasmic reticulum (ER) stress, probably by interfering with ER-associated degradation (ERAD). Here we report that mutant htt interacts and interferes with the function of gp78, an ER membrane-anchored ubiquitin ligase (E3) involved in ERAD. Mapping studies showed that the HEAT repeats 2&3 of htt interact with the cue domain of gp78. The interaction competitively reduces polyubiquitinated protein binding to gp78 and also sterically blocks gp78 interaction of p97/VCP, a molecular chaperone that is essential for ERAD. These effects of htt negatively regulate the function of gp78 in ERAD and are aggravated by polyglutamine expansion. Paradoxically, gp78 is still able to ubiquitinate and facilitate degradation of htt proteins with expanded polyglutamine. The impairment of ERAD by mutant htt proteins is associated with induction of ER stress. Our studies provide a novel molecular mechanism that supports the involvement of ER stress in HD pathogenesis.
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Affiliation(s)
- Hui Yang
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, Maryland, United States of America
| | - Chao Liu
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, Maryland, United States of America
| | - Yongwang Zhong
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, Maryland, United States of America
| | - Shouqing Luo
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Mervyn J. Monteiro
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, Maryland, United States of America
| | - Shengyun Fang
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, Maryland, United States of America
- * E-mail:
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Pouladi MA, Xie Y, Skotte NH, Ehrnhoefer DE, Graham RK, Kim JE, Bissada N, Yang XW, Paganetti P, Friedlander RM, Leavitt BR, Hayden MR. Full-length huntingtin levels modulate body weight by influencing insulin-like growth factor 1 expression. Hum Mol Genet 2010; 19:1528-38. [PMID: 20097678 DOI: 10.1093/hmg/ddq026] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Levels of full-length huntingtin (FL htt) influence organ and body weight, independent of polyglutamine length. The growth hormone-insulin like growth factor-1 (GH-IGF-1) axis is well established as a regulator of organ growth and body weight. In this study, we investigate the involvement of the IGF-1 pathway in mediating the effect of htt on body weight. IGF-1 expression was examined in transgenic mouse lines expressing different levels of FL wild-type (WT) htt (YAC18 mice), FL mutant htt (YAC128 and BACHD mice) and truncated mutant htt (shortstop mice). We demonstrate that htt influences body weight by modulating the IGF-1 pathway. Plasma IGF-1 levels correlate with body weight and htt levels in the transgenic YAC mice expressing human htt. The effect of htt on IGF-1 expression is independent of CAG size. No effect on body weight is observed in transgenic YAC mice expressing a truncated N-terminal htt fragment (shortstop), indicating that FL htt is required for the modulation of IGF-1 expression. Treatment with 17beta-estradiol (17beta-ED) lowers the levels of circulating IGF-1 in mammals. Treatment of YAC128 with 17beta-ED, but not placebo, reduces plasma IGF-1 levels and decreases the body weight of YAC128 animals to WT levels. Furthermore, given the ubiquitous expression of IGF-1 within the central nervous system, we also examined the impact of FL htt levels on IGF-1 expression in different regions of the brain, including the striatum, cerebellum of YAC18, YAC128 and littermate WT mice. We demonstrate that the levels of FL htt influence IGF-1 expression in striatal tissues. Our data identify a novel function for FL htt in influencing IGF-1 expression.
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Affiliation(s)
- Mahmoud A Pouladi
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, and Child and Family Research Institute, Vancouver, BC, Canada V5Z 4H4
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345
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Joyner PM, Matheke RM, Smith LM, Cichewicz RH. Probing the metabolic aberrations underlying mutant huntingtin toxicity in yeast and assessing their degree of preservation in humans and mice. J Proteome Res 2010; 9:404-12. [PMID: 19908918 PMCID: PMC2801778 DOI: 10.1021/pr900734g] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Metabolomics is a powerful multiparameter tool for evaluating phenotypic traits associated with disease processes. We have used (1)H NMR metabolome profiling to characterize metabolic aberrations in a yeast model of Huntington's disease that are attributable to the mutant huntingtin protein's gain-of-toxic-function effects. A group of 11 metabolites (alanine, acetate, galactose, glutamine, glycerol, histidine, proline, succinate, threonine, trehalose, and valine) exhibited significant concentration changes in yeast expressing the N-terminal fragment of a mutant human huntingtin gene. Correspondence analysis was used to compare results from our yeast model to data reported from transgenic mice expressing a mutant huntingtin gene fragment and Huntington's disease patients. This technique enabled us to identify a variety of both model-specific (pertaining to a single species) and conserved (observed in multiple species) biomarkers related to mutant huntingtin's toxicity. Among the 59 metabolites identified, four compounds (alanine, glutamine, glycerol, and valine) changed significantly in concentration in all three Huntington's disease systems. We propose that alanine, glutamine, glycerol, and valine should be considered as promising biomarkers for evaluating new Huntington's disease therapies, as well as for providing unique insight into the mechanisms associated with mutant huntingtin toxicity.
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Affiliation(s)
- P. Matthew Joyner
- Natural Products Discovery Group, Department of Chemistry and Biochemistry, 620 Parrington Oval, Room 208, University of Oklahoma, Norman, Oklahoma, 73019-3032, USA
| | - Ronni M. Matheke
- Natural Products Discovery Group, Department of Chemistry and Biochemistry, 620 Parrington Oval, Room 208, University of Oklahoma, Norman, Oklahoma, 73019-3032, USA
| | - Lindsey M. Smith
- Natural Products Discovery Group, Department of Chemistry and Biochemistry, 620 Parrington Oval, Room 208, University of Oklahoma, Norman, Oklahoma, 73019-3032, USA
| | - Robert H. Cichewicz
- Natural Products Discovery Group, Department of Chemistry and Biochemistry, 620 Parrington Oval, Room 208, University of Oklahoma, Norman, Oklahoma, 73019-3032, USA
- Cellular and Behavioral Neurobiology Graduate Program, University of Oklahoma, Norman, Oklahoma, 73019-3032, USA
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Shaw BF, Moustakas DT, Whitelegge JP, Faull KF. Taking Charge of Proteins. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2010; 79:127-64. [DOI: 10.1016/s1876-1623(10)79004-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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347
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Damiano M, Galvan L, Déglon N, Brouillet E. Mitochondria in Huntington's disease. Biochim Biophys Acta Mol Basis Dis 2010; 1802:52-61. [DOI: 10.1016/j.bbadis.2009.07.012] [Citation(s) in RCA: 201] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 07/31/2009] [Accepted: 07/31/2009] [Indexed: 11/16/2022]
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348
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Jana NR. Role of the ubiquitin–proteasome system and autophagy in polyglutamine neurodegenerative diseases. FUTURE NEUROLOGY 2010. [DOI: 10.2217/fnl.09.69] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The accumulation of intracellular protein aggregates is a prominent feature of many late-onset neurodegenerative disorders, including polyglutamine neurodegenerative diseases. Appearance of aggregates of the misfolded mutant disease proteins indicate that the degradative pathways of the cell are failing to efficiently clear them and are being progressively overwhelmed, which could eventually lead to neuronal dysfunction and neurodegeneration. Cellular pathways for degrading misfolded and aggregated-prone proteins include the ubiquitin–proteasome system and autophagy. This article reviews recent studies that have shown a critical role of the ubiquitin–proteasome system and autophagy in the pathogenesis of polyglutamine diseases. Understanding the role of these two pathways in disease pathogenesis could open up a new attractive therapeutic avenue for polyglutamine and other related neurodegenerative disorders.
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Affiliation(s)
- Nihar Ranjan Jana
- Cellular & Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon 122 050, India
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349
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Discriminative behavioral assessment unveils remarkable reactive astrocytosis and early molecular correlates in basal ganglia of 3-nitropropionic acid subchronic treated rats. Neurochem Int 2010; 56:152-60. [DOI: 10.1016/j.neuint.2009.09.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 08/21/2009] [Accepted: 09/18/2009] [Indexed: 01/28/2023]
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350
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Wang HQ, Xu YX, Zhao XY, Zhao H, Yan J, Sun XB, Guo JC, Zhu CQ. Overexpression of F0F1-ATP synthase α suppresses mutant huntingtin aggregation and toxicity in vitro. Biochem Biophys Res Commun 2009; 390:1294-8. [DOI: 10.1016/j.bbrc.2009.10.139] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 10/26/2009] [Indexed: 12/14/2022]
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