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Lauretani F, Giallauria F, Testa C, Zinni C, Lorenzi B, Zucchini I, Salvi M, Napoli R, Maggio MG. Dopamine Pharmacodynamics: New Insights. Int J Mol Sci 2024; 25:5293. [PMID: 38791331 PMCID: PMC11121567 DOI: 10.3390/ijms25105293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 05/04/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
Dopamine is a key neurotransmitter involved in physiological processes such as motor control, motivation, reward, cognitive function, and maternal and reproductive behaviors. Therefore, dysfunctions of the dopaminergic system are related to a plethora of human diseases. Dopamine, via different circuitries implicated in compulsive behavior, reward, and habit formation, also represents a key player in substance use disorder and the formation and perpetuation of mechanisms leading to addiction. Here, we propose dopamine as a model not only of neurotransmission but also of neuromodulation capable of modifying neuronal architecture. Abuse of substances like methamphetamine, cocaine, and alcohol and their consumption over time can induce changes in neuronal activities. These modifications lead to synaptic plasticity and finally to morphological and functional changes, starting from maladaptive neuro-modulation and ending in neurodegeneration.
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Affiliation(s)
- Fulvio Lauretani
- Geriatric Clinic Unit, Geriatric-Rehabilitation Department, University Hospital, 43126 Parma, Italy; (C.T.); (C.Z.); (B.L.); (I.Z.); (M.S.); (M.G.M.)
- Cognitive and Motor Center, Medicine and Geriatric-Rehabilitation Department of Parma, University-Hospital of Parma, 43126 Parma, Italy
| | - Francesco Giallauria
- Department of Translational Medical Sciences, “Federico II” University of Naples, via S. Pansini 5, 80131 Naples, Italy; (F.G.); (R.N.)
| | - Crescenzo Testa
- Geriatric Clinic Unit, Geriatric-Rehabilitation Department, University Hospital, 43126 Parma, Italy; (C.T.); (C.Z.); (B.L.); (I.Z.); (M.S.); (M.G.M.)
| | - Claudia Zinni
- Geriatric Clinic Unit, Geriatric-Rehabilitation Department, University Hospital, 43126 Parma, Italy; (C.T.); (C.Z.); (B.L.); (I.Z.); (M.S.); (M.G.M.)
| | - Beatrice Lorenzi
- Geriatric Clinic Unit, Geriatric-Rehabilitation Department, University Hospital, 43126 Parma, Italy; (C.T.); (C.Z.); (B.L.); (I.Z.); (M.S.); (M.G.M.)
| | - Irene Zucchini
- Geriatric Clinic Unit, Geriatric-Rehabilitation Department, University Hospital, 43126 Parma, Italy; (C.T.); (C.Z.); (B.L.); (I.Z.); (M.S.); (M.G.M.)
| | - Marco Salvi
- Geriatric Clinic Unit, Geriatric-Rehabilitation Department, University Hospital, 43126 Parma, Italy; (C.T.); (C.Z.); (B.L.); (I.Z.); (M.S.); (M.G.M.)
| | - Raffaele Napoli
- Department of Translational Medical Sciences, “Federico II” University of Naples, via S. Pansini 5, 80131 Naples, Italy; (F.G.); (R.N.)
| | - Marcello Giuseppe Maggio
- Geriatric Clinic Unit, Geriatric-Rehabilitation Department, University Hospital, 43126 Parma, Italy; (C.T.); (C.Z.); (B.L.); (I.Z.); (M.S.); (M.G.M.)
- Cognitive and Motor Center, Medicine and Geriatric-Rehabilitation Department of Parma, University-Hospital of Parma, 43126 Parma, Italy
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Estrada-Sánchez AM, Blake CL, Barton SJ, Howe AG, Rebec GV. Lack of mutant huntingtin in cortical efferents improves behavioral inflexibility and corticostriatal dynamics in Huntington's disease mice. J Neurophysiol 2019; 122:2621-2629. [PMID: 31693428 DOI: 10.1152/jn.00777.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Abnormal communication between cerebral cortex and striatum plays a major role in the motor symptoms of Huntington's disease (HD), a neurodegenerative disorder caused by a mutation of the huntingtin gene (mHTT). Because cortex is the main driver of striatal processing, we recorded local field potential (LFP) activity simultaneously in primary motor cortex (M1) and dorsal striatum (DS) in BACHD mice, a full-length HD gene model, and in a conditional BACHD/Emx-1 Cre (BE) model in which mHTT is suppressed in cortical efferents, while mice freely explored a plus-shaped maze beginning at 20 wk of age. Relative to wild-type (WT) controls, BACHD mice were just as active across >40 wk of testing but became progressively less likely to turn into a perpendicular arm as they approached the choice point of the maze, a sign of HD motor inflexibility. BE mice, in contrast, turned as freely as WT throughout testing. Although BE mice did not exactly match WT in LFP activity, the reduction in alpha (8-13 Hz), beta (13-30 Hz), and low-gamma (30-50 Hz) power that occurred in M1 of turning-impaired BACHD mice was reversed. No reversal occurred in DS. In fact, BE mice showed further reductions in DS theta (4-8 Hz), beta, and low-gamma power relative to the BACHD model. Coherence analysis indicated a dysregulation of corticostriatal information flow in both BACHD and BE mice. Collectively, our results suggest that mHTT in cortical outputs drives the dysregulation of select cortical frequencies that accompany the loss of behavioral flexibility in HD.NEW & NOTEWORTHY BACHD mice, a full-length genetic model of Huntington's disease (HD), express aberrant local field potential (LFP) activity in primary motor cortex (M1) along with decreased probability of turning into a perpendicular arm of a plus-shaped maze, a motor inflexibility phenotype. Suppression of the mutant huntingtin gene in cortical output neurons prevents decline in turning and improves alpha, beta, and low-gamma activity in M1. Our results implicate cortical networks in the search for therapeutic strategies to alleviate HD motor signs.
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Affiliation(s)
- Ana María Estrada-Sánchez
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana.,Departmento de Biología Molecular, Instituto Potosino De Investigación Científica y Tecnológica, San Luis Potosí, Mexico
| | - Courtney L Blake
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana
| | - Scott J Barton
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana
| | - Andrew G Howe
- Neuroscience Interdepartmental Program, University of California, Los Angeles, California.,Department of Psychology, University of California, Los Angeles, California
| | - George V Rebec
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana
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3
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Koch ET, Raymond LA. Dysfunctional striatal dopamine signaling in Huntington's disease. J Neurosci Res 2019; 97:1636-1654. [PMID: 31304622 DOI: 10.1002/jnr.24495] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/06/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022]
Abstract
Dopamine signaling in the striatum is critical for a variety of behaviors including movement, behavioral flexibility, response to reward and many forms of learning. Alterations to dopamine transmission contribute to pathological features of many neurological diseases, including Huntington's disease (HD). HD is an autosomal dominant genetic disorder caused by a CAG repeat expansion in the Huntingtin gene. The striatum is preferentially degenerated in HD, and this region receives dopaminergic input from the substantia nigra. Studies of HD patients and genetic rodent models have shown changes to levels of dopamine and its receptors in the striatum, and alterations in dopamine receptor signaling and modulation of other neurotransmitters, notably glutamate. Throughout his career, Dr. Michael Levine's research has furthered our understanding of dopamine signaling in the striatum of healthy rodents and HD mouse models. This review will focus on the work of his group and others in elucidating alterations to striatal dopamine signaling that contribute to pathophysiology in HD mouse models, and how these findings relate to human HD studies. We will also discuss current and potential therapeutic interventions for HD that target the dopamine system, and future research directions for this field.
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Affiliation(s)
- Ellen T Koch
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Lynn A Raymond
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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Tyebji S, Seizova S, Hannan AJ, Tonkin CJ. Toxoplasmosis: A pathway to neuropsychiatric disorders. Neurosci Biobehav Rev 2018; 96:72-92. [PMID: 30476506 DOI: 10.1016/j.neubiorev.2018.11.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 10/23/2018] [Accepted: 11/22/2018] [Indexed: 12/24/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite that resides, in a latent form, in the human central nervous system. Infection with Toxoplasma drastically alters the behaviour of rodents and is associated with the incidence of specific neuropsychiatric conditions in humans. But the question remains: how does this pervasive human pathogen alter behaviour of the mammalian host? This fundamental question is receiving increasing attention as it has far reaching public health implications for a parasite that is very common in human populations. Our current understanding centres on neuronal changes that are elicited directly by this intracellular parasite versus indirect changes that occur due to activation of the immune system within the CNS, or a combination of both. In this review, we explore the interactions between Toxoplasma and its host, the proposed mechanisms and consequences on neuronal function and mental health, and discuss Toxoplasma infection as a public health issue.
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Affiliation(s)
- Shiraz Tyebji
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, 3052, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, 3052, Australia; Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3052, Victoria, Australia.
| | - Simona Seizova
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, 3052, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, 3052, Australia.
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3052, Victoria, Australia; Department of Anatomy and Neuroscience, University of Melbourne, Parkville, 3052, Victoria, Australia.
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, 3052, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, 3052, Australia.
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Dopamine: Functions, Signaling, and Association with Neurological Diseases. Cell Mol Neurobiol 2018; 39:31-59. [PMID: 30446950 DOI: 10.1007/s10571-018-0632-3] [Citation(s) in RCA: 480] [Impact Index Per Article: 80.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/02/2018] [Indexed: 02/07/2023]
Abstract
The dopaminergic system plays important roles in neuromodulation, such as motor control, motivation, reward, cognitive function, maternal, and reproductive behaviors. Dopamine is a neurotransmitter, synthesized in both central nervous system and the periphery, that exerts its actions upon binding to G protein-coupled receptors. Dopamine receptors are widely expressed in the body and function in both the peripheral and the central nervous systems. Dopaminergic signaling pathways are crucial to the maintenance of physiological processes and an unbalanced activity may lead to dysfunctions that are related to neurodegenerative diseases. Unveiling the neurobiology and the molecular mechanisms that underlie these illnesses may contribute to the development of new therapies that could promote a better quality of life for patients worldwide. In this review, we summarize the aspects of dopamine as a catecholaminergic neurotransmitter and discuss dopamine signaling pathways elicited through dopamine receptor activation in normal brain function. Furthermore, we describe the potential involvement of these signaling pathways in evoking the onset and progression of some diseases in the nervous system, such as Parkinson's, Schizophrenia, Huntington's, Attention Deficit and Hyperactivity Disorder, and Addiction. A brief description of new dopaminergic drugs recently approved and under development treatments for these ailments is also provided.
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6
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Recombinant Adeno-Associated Virus-mediated rescue of function in a mouse model of Dopamine Transporter Deficiency Syndrome. Sci Rep 2017; 7:46280. [PMID: 28417953 PMCID: PMC5394687 DOI: 10.1038/srep46280] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/13/2017] [Indexed: 12/21/2022] Open
Abstract
Dopamine Transporter Deficiency Syndrome (DTDS) is a rare autosomal recessive disorder caused by loss-of-function mutations in dopamine transporter (DAT) gene, leading to severe neurological disabilities in children and adults. DAT-Knockout (DAT-KO) mouse is currently the best animal model for this syndrome, displaying functional hyperdopaminergia and neurodegenerative phenotype leading to premature death in ~36% of the population. We used DAT-KO mouse as model for DTDS to explore the potential utility of a novel combinatorial adeno-associated viral (AAV) gene therapy by expressing DAT selectively in DA neurons and terminals, resulting in the rescue of aberrant striatal DA dynamics, reversal of characteristic phenotypic and behavioral abnormalities, and prevention of premature death. These data indicate the efficacy of a new combinatorial gene therapy aimed at rescuing DA function and related phenotype in a mouse model that best approximates DAT deficiency found in DTDS.
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Metabolic signatures of Huntington's disease (HD): 1 H NMR analysis of the polar metabolome in post-mortem human brain. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1675-84. [DOI: 10.1016/j.bbadis.2016.06.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/27/2016] [Accepted: 06/07/2016] [Indexed: 12/22/2022]
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8
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Morigaki R, Goto S. Postsynaptic Density Protein 95 in the Striosome and Matrix Compartments of the Human Neostriatum. Front Neuroanat 2015; 9:154. [PMID: 26648848 PMCID: PMC4663261 DOI: 10.3389/fnana.2015.00154] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 11/16/2015] [Indexed: 11/13/2022] Open
Abstract
The human neostriatum consists of two functional subdivisions referred to as the striosome (patch) and matrix compartments. The striosome-matrix dopamine systems play a central role in cortico-thalamo-basal ganglia circuits, and their involvement is thought to underlie the genesis of multiple movement and behavioral disorders, and of drug addiction. Human neuropathology also has shown that striosomes and matrix have differential vulnerability patterns in several striatal neurodegenerative diseases. Postsynaptic density protein 95 (PSD-95), also known as disks large homolog 4, is a major scaffolding protein in the postsynaptic densities of dendritic spines. PSD-95 is now known to negatively regulate not only N-methyl-D-aspartate glutamate signaling, but also dopamine D1 signals at sites of postsynaptic transmission. Accordingly, a neuroprotective role for PSD-95 against dopamine D1 receptor (D1R)-mediated neurotoxicity in striatal neurodegeneration also has been suggested. Here, we used a highly sensitive immunohistochemistry technique to show that in the human neostriatum, PSD-95 is differentially concentrated in the striosome and matrix compartments, with a higher density of PSD-95 labeling in the matrix compartment than in the striosomes. This compartment-specific distribution of PSD-95 was strikingly complementary to that of D1R. In addition to the possible involvement of PSD-95-mediated synaptic function in compartment-specific dopamine signals, we suggest that the striosomes might be more susceptible to D1R-mediated neurotoxicity than the matrix compartment. This notion may provide new insight into the compartment-specific vulnerability of MSNs in striatal neurodegeneration.
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Affiliation(s)
- Ryoma Morigaki
- Department of Neurodegenerative Disorders Research, Institute of Biomedical Sciences, Graduate School of Medical Sciences, Tokushima University Tokushima, Japan ; Parkinson's Disease and Dystonia Research Center, Tokushima University Hospital, Tokushima University Tokushima, Japan ; Department of Neurosurgery, Institute of Biomedical Sciences, Graduate School of Medical Sciences, Tokushima University Tokushima, Japan
| | - Satoshi Goto
- Department of Neurodegenerative Disorders Research, Institute of Biomedical Sciences, Graduate School of Medical Sciences, Tokushima University Tokushima, Japan ; Parkinson's Disease and Dystonia Research Center, Tokushima University Hospital, Tokushima University Tokushima, Japan
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Vinther-Jensen T, Nielsen T, Budtz-Jørgensen E, Larsen I, Hansen M, Hasholt L, Hjermind L, Nielsen J, Nørremølle A. Psychiatric and cognitive symptoms in Huntington's disease are modified by polymorphisms in catecholamine regulating enzyme genes. Clin Genet 2015; 89:320-7. [DOI: 10.1111/cge.12628] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 06/12/2015] [Accepted: 06/15/2015] [Indexed: 12/20/2022]
Affiliation(s)
- T. Vinther-Jensen
- Neurogenetics Clinic, Danish Dementia Research Centre, Department of Neurology, Rigshospitalet; University of Copenhagen; Copenhagen Denmark
- Department of Cellular and Molecular Medicine, Section of Neurogenetics; University of Copenhagen; Copenhagen Denmark
| | - T.T. Nielsen
- Neurogenetics Clinic, Danish Dementia Research Centre, Department of Neurology, Rigshospitalet; University of Copenhagen; Copenhagen Denmark
- Neurogenetics Research Laboratory, Danish Dementia Research Centre, Department of Neurology, Rigshospitalet; University of Copenhagen; Copenhagen Denmark
| | - E. Budtz-Jørgensen
- Department of Biostatistics; University of Copenhagen; Copenhagen Denmark
| | - I.U. Larsen
- Neurogenetics Clinic, Danish Dementia Research Centre, Department of Neurology, Rigshospitalet; University of Copenhagen; Copenhagen Denmark
- Department of Psychology; University of Copenhagen; Copenhagen Denmark
| | - M.M. Hansen
- Department of Cellular and Molecular Medicine, Section of Neurogenetics; University of Copenhagen; Copenhagen Denmark
| | - L. Hasholt
- Department of Cellular and Molecular Medicine, Section of Neurogenetics; University of Copenhagen; Copenhagen Denmark
| | - L.E. Hjermind
- Neurogenetics Clinic, Danish Dementia Research Centre, Department of Neurology, Rigshospitalet; University of Copenhagen; Copenhagen Denmark
- Department of Cellular and Molecular Medicine, Section of Neurogenetics; University of Copenhagen; Copenhagen Denmark
| | - J.E. Nielsen
- Neurogenetics Clinic, Danish Dementia Research Centre, Department of Neurology, Rigshospitalet; University of Copenhagen; Copenhagen Denmark
- Department of Cellular and Molecular Medicine, Section of Neurogenetics; University of Copenhagen; Copenhagen Denmark
- Neurogenetics Research Laboratory, Danish Dementia Research Centre, Department of Neurology, Rigshospitalet; University of Copenhagen; Copenhagen Denmark
| | - A. Nørremølle
- Department of Cellular and Molecular Medicine, Section of Neurogenetics; University of Copenhagen; Copenhagen Denmark
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Cortical efferents lacking mutant huntingtin improve striatal neuronal activity and behavior in a conditional mouse model of Huntington's disease. J Neurosci 2015; 35:4440-51. [PMID: 25762686 DOI: 10.1523/jneurosci.2812-14.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Abnormal electrophysiological activity in the striatum, which receives dense innervation from the cerebral cortex, is believed to set the stage for the behavioral phenotype observed in Huntington's disease (HD), a neurodegenerative condition caused by mutation of the huntingtin (mhtt) protein. However, cortical involvement is far from clear. To determine whether abnormal striatal processing can be explained by mhtt alone (cell-autonomous model) or by mhtt in the corticostriatal projection cell-cell interaction model, we used BACHD/Emx1-Cre (BE) mice, a conditional HD model in which full-length mhtt is genetically reduced in cortical output neurons, including those that project to the striatum. Animals were assessed beginning at 20 weeks of age for at least the next 40 weeks, a range over which presymptomatic BACHD mice become symptomatic. Both open-field and nest-building behavior deteriorated progressively in BACHD mice relative to both BE and wild-type (WT) mice. Neuronal activity patterns in the dorsal striatum, which receives input from the primary motor cortex (M1), followed a similar age progression because BACHD activity changed more rapidly than either BE or WT mice. However, in the M1, BE neuronal activity differed significantly from both WT and BACHD. Although abnormal cortical activity in BE mice likely reflects input from mhtt-expressing afferents, including cortical interneurons, improvements in BE striatal activity and behavior suggest a critical role for mhtt in cortical output neurons in shaping the onset and progression of striatal dysfunction.
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Dallérac GM, Levasseur G, Vatsavayai SC, Milnerwood AJ, Cummings DM, Kraev I, Huetz C, Evans KA, Walters SW, Rezaie P, Cho Y, Hirst MC, Murphy KP. Dysfunctional Dopaminergic Neurones in Mouse Models of Huntington's Disease: A Role for SK3 Channels. NEURODEGENER DIS 2015; 15:93-108. [DOI: 10.1159/000375126] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/12/2015] [Indexed: 11/19/2022] Open
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12
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Lebel M, Robinson P, Cyr M. Canadian Association of Neurosciences Review: The Role of Dopamine Receptor Function in Neurodegenerative Diseases. Can J Neurol Sci 2014; 34:18-29. [PMID: 17352343 DOI: 10.1017/s0317167100005746] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Dopamine (DA) receptors, which are heavily expressed in the caudate/putamen of the brain, represent the molecular target of several drugs used in the treatment of various neurological disorders, such as Parkinson's disease. Although most of the drugs are very effective in alleviating the symptoms associated with these conditions, their long-term utilization could lead to the development of severe side-effects. In addition to uncovering novel mediators of physiological DA receptor functions, recent research advances are suggesting a role of these receptors in toxic effects on neurons. For instance, accumulating evidence indicates that DA receptors, particularly D1 receptors, are central in the neuronal toxicity induced by elevated synaptic levels of DA. In this review, we will discuss recent findings on DA receptors as regulators of long term neuronal dysfunction and neurodegenerative processes.
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Affiliation(s)
- Manon Lebel
- Neuroscience Research Group, Université du Québec à Trois-Rivières, Canada
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Francelle L, Galvan L, Brouillet E. Possible involvement of self-defense mechanisms in the preferential vulnerability of the striatum in Huntington's disease. Front Cell Neurosci 2014; 8:295. [PMID: 25309327 PMCID: PMC4176035 DOI: 10.3389/fncel.2014.00295] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 09/03/2014] [Indexed: 01/01/2023] Open
Abstract
HD is caused by a mutation in the huntingtin gene that consists in a CAG repeat expansion translated into an abnormal poly-glutamine (polyQ) tract in the huntingtin (Htt) protein. The most striking neuropathological finding in HD is the atrophy of the striatum. The regional expression of mutant Htt (mHtt) is ubiquitous in the brain and cannot explain by itself the preferential vulnerability of the striatum in HD. mHtt has been shown to produce an early defect in transcription, through direct alteration of the function of key regulators of transcription and in addition, more indirectly, as a result of compensatory responses to cellular stress. In this review, we focus on gene products that are preferentially expressed in the striatum and have down- or up-regulated expression in HD and, as such, may play a crucial role in the susceptibility of the striatum to mHtt. Many of these striatal gene products are for a vast majority down-regulated and more rarely increased in HD. Recent research shows that some of these striatal markers have a pro-survival/neuroprotective role in neurons (e.g., MSK1, A2A, and CB1 receptors) whereas others enhance the susceptibility of striatal neurons to mHtt (e.g., Rhes, RGS2, D2 receptors). The down-regulation of these latter proteins may be considered as a potential self-defense mechanism to slow degeneration. For a majority of the striatal gene products that have been identified so far, their function in the striatum is unknown and their modifying effects on mHtt toxicity remain to be experimentally addressed. Focusing on these striatal markers may contribute to a better understanding of HD pathogenesis, and possibly the identification of novel therapeutic targets.
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Affiliation(s)
- Laetitia Francelle
- Neurodegenerative Disease Laboratory, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Direction des Sciences du Vivant, Institut d'Imagerie BioMédicale, Molecular Imaging Research Center Fontenay-aux-Roses, France ; Centre National de la Recherche Scientifique - Commissariat à l'Énergie Atomique et aux Énergies Alternatives Unité de Recherche Associée 2210 Fontenay-aux-Roses, France
| | - Laurie Galvan
- Neurodegenerative Disease Laboratory, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Direction des Sciences du Vivant, Institut d'Imagerie BioMédicale, Molecular Imaging Research Center Fontenay-aux-Roses, France ; Centre National de la Recherche Scientifique - Commissariat à l'Énergie Atomique et aux Énergies Alternatives Unité de Recherche Associée 2210 Fontenay-aux-Roses, France ; Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, David Geffen School of Medicine, University of California Los Angeles Los Angeles, CA, USA
| | - Emmanuel Brouillet
- Neurodegenerative Disease Laboratory, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Direction des Sciences du Vivant, Institut d'Imagerie BioMédicale, Molecular Imaging Research Center Fontenay-aux-Roses, France ; Centre National de la Recherche Scientifique - Commissariat à l'Énergie Atomique et aux Énergies Alternatives Unité de Recherche Associée 2210 Fontenay-aux-Roses, France
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Podder A, Jatana N, Latha N. Human Dopamine Receptors Interaction Network (DRIN): A systems biology perspective on topology, stability and functionality of the network. J Theor Biol 2014; 357:169-83. [DOI: 10.1016/j.jtbi.2014.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 04/05/2014] [Accepted: 05/09/2014] [Indexed: 01/11/2023]
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15
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Cassar M, Issa AR, Riemensperger T, Petitgas C, Rival T, Coulom H, Iché-Torres M, Han KA, Birman S. A dopamine receptor contributes to paraquat-induced neurotoxicity in Drosophila. Hum Mol Genet 2014; 24:197-212. [PMID: 25158689 DOI: 10.1093/hmg/ddu430] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Long-term exposure to environmental oxidative stressors, like the herbicide paraquat (PQ), has been linked to the development of Parkinson's disease (PD), the most frequent neurodegenerative movement disorder. Paraquat is thus frequently used in the fruit fly Drosophila melanogaster and other animal models to study PD and the degeneration of dopaminergic neurons (DNs) that characterizes this disease. Here, we show that a D1-like dopamine (DA) receptor, DAMB, actively contributes to the fast central nervous system (CNS) failure induced by PQ in the fly. First, we found that a long-term increase in neuronal DA synthesis reduced DAMB expression and protected against PQ neurotoxicity. Secondly, a striking age-related decrease in PQ resistance in young adult flies correlated with an augmentation of DAMB expression. This aging-associated increase in oxidative stress vulnerability was not observed in a DAMB-deficient mutant. Thirdly, targeted inactivation of this receptor in glutamatergic neurons (GNs) markedly enhanced the survival of Drosophila exposed to either PQ or neurotoxic levels of DA, whereas, conversely, DAMB overexpression in these cells made the flies more vulnerable to both compounds. Fourthly, a mutation in the Drosophila ryanodine receptor (RyR), which inhibits activity-induced increase in cytosolic Ca(2+), also strongly enhanced PQ resistance. Finally, we found that DAMB overexpression in specific neuronal populations arrested development of the fly and that in vivo stimulation of either DNs or GNs increased PQ susceptibility. This suggests a model for DA receptor-mediated potentiation of PQ-induced neurotoxicity. Further studies of DAMB signaling in Drosophila could have implications for better understanding DA-related neurodegenerative disorders in humans.
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Affiliation(s)
- Marlène Cassar
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France
| | - Abdul-Raouf Issa
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France
| | - Thomas Riemensperger
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France
| | - Céline Petitgas
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France
| | - Thomas Rival
- Genetics and Physiopathology of Neurotransmission, Developmental Biology Institute of Marseille-Luminy, CNRS, Université de la Méditerranée, 13009 Marseille, France and
| | - Hélène Coulom
- Genetics and Physiopathology of Neurotransmission, Developmental Biology Institute of Marseille-Luminy, CNRS, Université de la Méditerranée, 13009 Marseille, France and
| | - Magali Iché-Torres
- Genetics and Physiopathology of Neurotransmission, Developmental Biology Institute of Marseille-Luminy, CNRS, Université de la Méditerranée, 13009 Marseille, France and
| | - Kyung-An Han
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
| | - Serge Birman
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France Genetics and Physiopathology of Neurotransmission, Developmental Biology Institute of Marseille-Luminy, CNRS, Université de la Méditerranée, 13009 Marseille, France and
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16
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Krogsgaard-Larsen N, Harpsøe K, Kehler J, Christoffersen CT, Brøsen P, Balle T. Revision of the classical dopamine D2 agonist pharmacophore based on an integrated medicinal chemistry, homology modelling and computational docking approach. Neurochem Res 2014; 39:1997-2007. [PMID: 25056287 DOI: 10.1007/s11064-014-1314-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 04/07/2014] [Accepted: 04/16/2014] [Indexed: 01/08/2023]
Abstract
The scientific advances during the 1970ies and 1980ies within the field of dopaminergic neurotransmission enabled the development of a pharmacophore that became the template for design and synthesis of dopamine D2 agonists during the following four decades. A major drawback, however, is that this model fails to accommodate certain classes of restrained dopamine D2 agonists including ergoline structures. To accommodate these, a revision of the original model was required. The present study has addressed this by an extension of the original model without compromising its obvious qualities. The revised pharmacophore contains an additional hydrogen bond donor feature, which is required for it to accommodate ergoline structures in a low energy conformation and in accordance with the steric restrictions dictated by the original model. The additional pharmacophore feature suggests ambiguity in the binding mode for certain compounds, including a series of ergoline analogues, which was reported recently. The ambiguity was confirmed by docking to a homology model of the D2 receptor as well as by pharmacological characterization of individual enantiomers of one of the analogues. The present research also addresses the potential of designing ligands that interact with the receptor in a large, distal cavity of the dopamine D2 receptor that has not previously been studied systematically. The pharmacological data indicate that this area may be a major determinant for both the dopamine D2 affinity and efficacy, which remains to be explored in future studies.
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Affiliation(s)
- N Krogsgaard-Larsen
- Department of Drug Design and Pharmacology, The Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100, Copenhagen, Denmark
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17
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Marion S, Urs NM, Peterson SM, Sotnikova TD, Beaulieu JM, Gainetdinov RR, Caron MG. Dopamine D2 receptor relies upon PPM/PP2C protein phosphatases to dephosphorylate huntingtin protein. J Biol Chem 2014; 289:11715-11724. [PMID: 24619418 PMCID: PMC4002081 DOI: 10.1074/jbc.m113.544312] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 02/26/2014] [Indexed: 12/24/2022] Open
Abstract
Striatal dopamine D2 receptor (D2R) relies upon G protein- and β-arrestin-dependent signaling pathways to convey its action on motor control and behavior. Considering that D2R activation inhibits Akt in the striatum and that huntingtin physiological functions are affected by Akt phosphorylation, we sought to investigate whether D2R-mediated signaling could regulate huntingtin phosphorylation. We demonstrate that D2R activation decreases huntingtin phosphorylation on its Akt site. This dephosphorylation event depends upon the Gαi-dependent engagement of specific members of the protein phosphatase metallo-dependent (PPM/PP2C) family and is independent of β-arrestin 2. These observations identify the PPM/PP2C family as a mediator of G protein-coupled receptor signaling and thereby suggest a novel mechanism of dopaminergic signaling.
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Affiliation(s)
- Sébastien Marion
- Departments of Cell Biology, Neurobiology Duke University Medical Center, Durham, North Carolina 27710
| | - Nikhil M Urs
- Departments of Cell Biology, Neurobiology Duke University Medical Center, Durham, North Carolina 27710
| | - Sean M Peterson
- Departments of Cell Biology, Neurobiology Duke University Medical Center, Durham, North Carolina 27710
| | - Tatyana D Sotnikova
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval/IUSMQ, Québec G1J 2G3, Canada
| | - Jean-Martin Beaulieu
- Department of Neuroscience, Italian Institute of Technology, 16163 Genova, Italy
| | - Raul R Gainetdinov
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval/IUSMQ, Québec G1J 2G3, Canada
| | - Marc G Caron
- Departments of Cell Biology, Neurobiology Duke University Medical Center, Durham, North Carolina 27710; Departments of Medicine, Neurobiology Duke University Medical Center, Durham, North Carolina 27710; Neurobiology Duke University Medical Center, Durham, North Carolina 27710.
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18
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Zhang J, Saur T, Duke AN, Grant SGN, Platt DM, Rowlett JK, Isacson O, Yao WD. Motor impairments, striatal degeneration, and altered dopamine-glutamate interplay in mice lacking PSD-95. J Neurogenet 2014; 28:98-111. [PMID: 24702501 DOI: 10.3109/01677063.2014.892486] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Excessive activation of the N-methyl-d-aspartate (NMDA) receptor and the neurotransmitter dopamine (DA) mediate neurotoxicity and neurodegeneration under many neurological conditions, including Huntington's disease (HD), an autosomal dominant neurodegenerative disease characterized by the preferential loss of medium spiny projection neurons (MSNs) in the striatum. PSD-95 is a major scaffolding protein in the postsynaptic density (PSD) of dendritic spines, where a classical role for PSD-95 is to stabilize glutamate receptors at sites of synaptic transmission. Our recent studies indicate that PSD-95 also interacts with the D1 DA receptor localized in spines and negatively regulates spine D1 signaling. Moreover, PSD-95 forms ternary protein complexes with D1 and NMDA receptors, and plays a role in limiting the reciprocal potentiation between both receptors from being escalated. These studies suggest a neuroprotective role for PSD-95. Here we show that mice lacking PSD-95, resulting from genetic deletion of the GK domain of PSD-95 (PSD-95-ΔGK mice), sporadically develop progressive neurological impairments characterized by hypolocomotion, limb clasping, and loss of DARPP-32-positive MSNs. Electrophysiological experiments indicated that NMDA receptors in mutant MSNs were overactive, suggested by larger, NMDA receptor-mediated miniature excitatory postsynaptic currents (EPSCs) and higher ratios of NMDA- to AMPA-mediated corticostriatal synaptic transmission. In addition, NMDA receptor currents in mutant cortical neurons were more sensitive to potentiation by the D1 receptor agonist SKF81297. Finally, repeated administration of the psychostimulant cocaine at a dose regimen not producing overt toxicity-related phenotypes in normal mice reliably converted asymptomatic mutant mice to clasping symptomatic mice. These results support the hypothesis that deletion of PSD-95 in mutant mice produces concomitant overactivation of both D1 and NMDA receptors that makes neurons more susceptible to NMDA excitotoxicity, causing neuronal damage and neurological impairments. Understanding PSD-95-dependent neuroprotective mechanisms may help elucidate processes underlying neurodegeneration in HD and other neurological disorders.
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Affiliation(s)
- Jingping Zhang
- New England Primate Research Center, Harvard Medical School , Southborough, Massachusetts , USA
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19
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Chen JY, Wang EA, Cepeda C, Levine MS. Dopamine imbalance in Huntington's disease: a mechanism for the lack of behavioral flexibility. Front Neurosci 2013; 7:114. [PMID: 23847463 PMCID: PMC3701870 DOI: 10.3389/fnins.2013.00114] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/13/2013] [Indexed: 01/10/2023] Open
Abstract
Dopamine (DA) plays an essential role in the control of coordinated movements. Alterations in DA balance in the striatum lead to pathological conditions such as Parkinson's and Huntington's diseases (HD). HD is a progressive, invariably fatal neurodegenerative disease caused by a genetic mutation producing an expansion of glutamine repeats and is characterized by abnormal dance-like movements (chorea). The principal pathology is the loss of striatal and cortical projection neurons. Changes in brain DA content and receptor number contribute to abnormal movements and cognitive deficits in HD. In particular, during the early hyperkinetic stage of HD, DA levels are increased whereas expression of DA receptors is reduced. In contrast, in the late akinetic stage, DA levels are significantly decreased and resemble those of a Parkinsonian state. Time-dependent changes in DA transmission parallel biphasic changes in glutamate synaptic transmission and may enhance alterations in glutamate receptor-mediated synaptic activity. In this review, we focus on neuronal electrophysiological mechanisms that may lead to some of the motor and cognitive symptoms of HD and how they relate to dysfunction in DA neurotransmission. Based on clinical and experimental findings, we propose that some of the behavioral alterations in HD, including reduced behavioral flexibility, may be caused by altered DA modulatory function. Thus, restoring DA balance alone or in conjunction with glutamate receptor antagonists could be a viable therapeutic approach.
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Affiliation(s)
- Jane Y Chen
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior and the Brain Research Institute, David Geffen School of Medicine, University of California Los Angeles Los Angeles, CA, USA
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20
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Jimenez-Shahed J, Jankovic J. Tetrabenazine for treatment of chorea associated with Huntington's disease and other potential indications. Expert Opin Orphan Drugs 2013. [DOI: 10.1517/21678707.2013.787358] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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21
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Gil-Mohapel JM. Screening of therapeutic strategies for Huntington's disease in YAC128 transgenic mice. CNS Neurosci Ther 2012; 18:77-86. [PMID: 21501423 DOI: 10.1111/j.1755-5949.2011.00246.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Huntington’s disease (HD) is a hereditary neurodegenerative disorder caused by an unstable expansion of cytosine-adenine-guanine (CAG) repeats in the HD gene. The symptoms include cognitive dysfunction and severe motor impairment with loss of voluntary movement coordination that is later replaced by bradykinesia and rigidity. The neuropathology is characterized by neuronal loss mainly in the striatum and cortex, and the appearance of neuronal intranuclear inclusions of mutant huntingtin. The mechanisms responsible for neurodegeneration are still not fully understood although excitotoxicity and a consequent increase in intracellular calcium concentration as well as the activation of caspases and calapins are known to play a key role. There is currently no satisfactory treatment or cure for this disease. The YAC128 transgenic mice express the full-length human HD gene with 128 CAG repeats and constitute a unique model for the study of HD as they replicate the slow and biphasic progression of behavioral deficits characteristic of the human condition and show striatal neuronal loss. As such, these transgenic mice have been an invaluable model not only for the elucidation of the neurodegenerative pathways in HD, but also for the screening and development of new therapeutic approaches. Here, I will review the unique characteristics of this transgenic HD model and will provide a summary of the therapies that have been tested in these mice, namely: potentiation of the protective roles of wild-type huntingtin and mutant huntingtin aggregation, transglutaminase inhibition, inhibition of glutamate- and dopamine-induced toxicity, apoptosis inhibition, use of essential fatty acids, and the novel approach of intrabody gene therapy. The insights obtained from these and future studies will help identify potential candidates for clinical trials and will ultimately contribute to the discovery of a successful treatment for this devastating neurodegenerative disorder.
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Affiliation(s)
- Joana M Gil-Mohapel
- Division of Medical Sciences, Island Medical Program, University of Victoria, British Columbia, Canada.
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22
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Dysregulation of dopamine receptor D2 as a sensitive measure for Huntington disease pathology in model mice. Proc Natl Acad Sci U S A 2012; 109:7487-92. [PMID: 22529362 DOI: 10.1073/pnas.1204542109] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability to quantitatively evaluate the impact of a potential therapeutic intervention for Huntington disease (HD) in animal models for the disease is a critical step in the pathway to development of an effective therapy for this devastating neurodegenerative disorder. We report here an approach that combines a cell-based assay's quantitative accuracy and direct relationship to molecular processes with the ability to directly monitor effects in HD model mouse neurons. To accomplish this goal, we have developed an accurate quantitative reporter assay for a transcript known to be down-regulated as an early consequence of mutant huntingtin expression. This system uses mouse strains carrying a GFP reporter for the expression of the dopamine receptor D2, expressed in the medium spiny neurons of the basal ganglion. This receptor consistently demonstrates reduced expression in patients and murine models, and the FACS-based assay gives a highly accurate and quantitative readout of this pathology in mouse neurons expressing mutant huntingtin. For four genetic models and one viral model, a highly reproducible time course of loss of reporter expression is observed. This quantitative measure of HD pathology can be used to measure the effects of HD therapeutics in small cohorts with high confidence. We further demonstrate that the introduction of an shRNA against the huntingtin transgene by virus can improve this pathological status in medium spiny neurons transduced with the construct. We believe this system can be of great utility in the validation of effective therapeutic interventions for HD.
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Roze E, Cahill E, Martin E, Bonnet C, Vanhoutte P, Betuing S, Caboche J. Huntington's Disease and Striatal Signaling. Front Neuroanat 2011; 5:55. [PMID: 22007160 PMCID: PMC3188786 DOI: 10.3389/fnana.2011.00055] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 08/04/2011] [Indexed: 12/05/2022] Open
Abstract
Huntington’s Disease (HD) is the most frequent neurodegenerative disease caused by an expansion of polyglutamines (CAG). The main clinical manifestations of HD are chorea, cognitive impairment, and psychiatric disorders. The transmission of HD is autosomal dominant with a complete penetrance. HD has a single genetic cause, a well-defined neuropathology, and informative pre-manifest genetic testing of the disease is available. Striatal atrophy begins as early as 15 years before disease onset and continues throughout the period of manifest illness. Therefore, patients could theoretically benefit from therapy at early stages of the disease. One important characteristic of HD is the striatal vulnerability to neurodegeneration, despite similar expression of the protein in other brain areas. Aggregation of the mutated Huntingtin (HTT), impaired axonal transport, excitotoxicity, transcriptional dysregulation as well as mitochondrial dysfunction, and energy deficits, are all part of the cellular events that underlie neuronal dysfunction and striatal death. Among these non-exclusive mechanisms, an alteration of striatal signaling is thought to orchestrate the downstream events involved in the cascade of striatal dysfunction.
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Affiliation(s)
- Emmanuel Roze
- UMRS 952, INSERM, UMR 7224, CNRS Université Pierre et Marie Curie - Paris-6 Paris, France
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24
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Beaulieu JM, Gainetdinov RR. The physiology, signaling, and pharmacology of dopamine receptors. Pharmacol Rev 2011; 63:182-217. [PMID: 21303898 DOI: 10.1124/pr.110.002642] [Citation(s) in RCA: 1802] [Impact Index Per Article: 138.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
G protein-coupled dopamine receptors (D1, D2, D3, D4, and D5) mediate all of the physiological functions of the catecholaminergic neurotransmitter dopamine, ranging from voluntary movement and reward to hormonal regulation and hypertension. Pharmacological agents targeting dopaminergic neurotransmission have been clinically used in the management of several neurological and psychiatric disorders, including Parkinson's disease, schizophrenia, bipolar disorder, Huntington's disease, attention deficit hyperactivity disorder (ADHD(1)), and Tourette's syndrome. Numerous advances have occurred in understanding the general structural, biochemical, and functional properties of dopamine receptors that have led to the development of multiple pharmacologically active compounds that directly target dopamine receptors, such as antiparkinson drugs and antipsychotics. Recent progress in understanding the complex biology of dopamine receptor-related signal transduction mechanisms has revealed that, in addition to their primary action on cAMP-mediated signaling, dopamine receptors can act through diverse signaling mechanisms that involve alternative G protein coupling or through G protein-independent mechanisms via interactions with ion channels or proteins that are characteristically implicated in receptor desensitization, such as β-arrestins. One of the future directions in managing dopamine-related pathologic conditions may involve a transition from the approaches that directly affect receptor function to a precise targeting of postreceptor intracellular signaling modalities either directly or through ligand-biased signaling pharmacology. In this comprehensive review, we discuss dopamine receptor classification, their basic structural and genetic organization, their distribution and functions in the brain and the periphery, and their regulation and signal transduction mechanisms. In addition, we discuss the abnormalities of dopamine receptor expression, function, and signaling that are documented in human disorders and the current pharmacology and emerging trends in the development of novel therapeutic agents that act at dopamine receptors and/or on related signaling events.
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Affiliation(s)
- Jean-Martin Beaulieu
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval–Centre de Recherche de l'Université Laval Robert-Giffard, Québec-City, Québec, Canada
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25
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Eidelberg D, Surmeier DJ. Brain networks in Huntington disease. J Clin Invest 2011; 121:484-92. [PMID: 21285521 DOI: 10.1172/jci45646] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Recent studies have focused on understanding the neural mechanisms underlying the emergence of clinical signs and symptoms in early stage Huntington disease (HD). Although cell-based assays have focused on cell autonomous effects of mutant huntingtin, animal HD models have revealed alterations in the function of neuronal networks, particularly those linking the cerebral cortex and striatum. These findings are complemented by metabolic imaging studies of disease progression in premanifest subjects. Quantifying metabolic progression at the systems level may identify network biomarkers to aid in the objective assessment of new disease-modifying therapies and identify new regions that merit mechanistic study in HD models.
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Affiliation(s)
- David Eidelberg
- Center for Neurosciences, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, New York 11030, USA.
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26
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Ribeiro FM, Pires RGW, Ferguson SSG. Huntington's disease and Group I metabotropic glutamate receptors. Mol Neurobiol 2010; 43:1-11. [PMID: 21153060 DOI: 10.1007/s12035-010-8153-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 11/15/2010] [Indexed: 12/21/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by involuntary body movement, cognitive impairment and psychiatric disturbance. A polyglutamine expansion in the amino-terminal region of the huntingtin (htt) protein is the genetic cause of HD. Htt protein interacts with a wide variety of proteins, and htt mutation causes cell signaling alterations in various neurotransmitter systems, including dopaminergic, glutamatergic, and cannabinoid systems, as well as trophic factor systems. This review will overview recent findings concerning htt-promoted alterations in cell signaling that involve different neurotransmitters and trophic factor systems, especially involving mGluR1/5, as glutamate plays a crucial role in neuronal cell death. The neuronal cell death that takes place in the striatum and cortex of HD patients is the most important factor underlying HD progression. Metabotropic glutamate receptors (mGluR1 and mGluR5) have a very controversial role in neuronal cell death and it is not clear whether mGluR1/5 activation either protects or exacerbates neuronal death. Thus, understanding how mutant htt protein affects glutamatergic receptor signaling will be essential to further establish a role for glutamate receptors in HD and develop therapeutic strategies to treat HD.
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Affiliation(s)
- Fabiola M Ribeiro
- Departamento de Bioquimica e Imunologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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27
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Miller BR, Bezprozvanny I. Corticostriatal circuit dysfunction in Huntington's disease: intersection of glutamate, dopamine and calcium. FUTURE NEUROLOGY 2010; 5:735-756. [PMID: 21977007 DOI: 10.2217/fnl.10.41] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Huntington's disease (HD) is a noncurable and progressive autosomal-dominant neurodegenerative disorder that results from a polyglutamine expansion in the amino-terminal region of the huntingtin protein. The generation of rodent HD models has revealed that cellular dysfunction, rather than cell death alone, occurs early in the disease progression, appearing even before overt symptom onset. Much evidence has now established that dysfunction of the corticostriatal circuit is key to HD symptomology. In this article, we summarize the most current findings that implicate glutamate, dopamine and calcium signaling in this system and discuss how they work in concert to disrupt corticostriatal function. In addition, we highlight therapeutic strategies related to altered corticostriatal signaling in HD.
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Affiliation(s)
- Benjamin Ray Miller
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
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28
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Dowie MJ, Scotter EL, Molinari E, Glass M. The therapeutic potential of G-protein coupled receptors in Huntington's disease. Pharmacol Ther 2010; 128:305-23. [PMID: 20708032 DOI: 10.1016/j.pharmthera.2010.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 07/14/2010] [Indexed: 01/29/2023]
Abstract
Huntington's disease is a late-onset autosomal dominant inherited neurodegenerative disease characterised by increased symptom severity over time and ultimately premature death. An expanded CAG repeat sequence in the huntingtin gene leads to a polyglutamine expansion in the expressed protein, resulting in complex dysfunctions including cellular excitotoxicity and transcriptional dysregulation. Symptoms include cognitive deficits, psychiatric changes and a movement disorder often referred to as Huntington's chorea, which involves characteristic involuntary dance-like writhing movements. Neuropathologically Huntington's disease is characterised by neuronal dysfunction and death in the striatum and cortex with an overall decrease in cerebral volume (Ho et al., 2001). Neuronal dysfunction begins prior to symptom presentation, and cells of particular vulnerability include the striatal medium spiny neurons. Huntington's is a devastating disease for patients and their families and there is currently no cure, or even an effective therapy for disease symptoms. G-protein coupled receptors are the most abundant receptor type in the central nervous system and are linked to complex downstream pathways, manipulation of which may have therapeutic application in many neurological diseases. This review will highlight the potential of G-protein coupled receptor drug targets as emerging therapies for Huntington's disease.
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Affiliation(s)
- Megan J Dowie
- Centre for Brain Research, University of Auckland, Private Bag 92019 Auckland, New Zealand
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29
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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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Wang H, Chen X, Li Y, Tang TS, Bezprozvanny I. Tetrabenazine is neuroprotective in Huntington's disease mice. Mol Neurodegener 2010; 5:18. [PMID: 20420689 PMCID: PMC2873255 DOI: 10.1186/1750-1326-5-18] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Accepted: 04/26/2010] [Indexed: 11/22/2022] Open
Abstract
Background Huntington's disease (HD) is a neurodegenerative disorder caused by a polyglutamine (polyQ) expansion in Huntingtin protein (Htt). PolyQ expansion in Httexp causes selective degeneration of striatal medium spiny neurons (MSN) in HD patients. A number of previous studies suggested that dopamine signaling plays an important role in HD pathogenesis. A specific inhibitor of vesicular monoamine transporter (VMAT2) tetrabenazine (TBZ) has been recently approved by Food and Drug Administration for treatment of HD patients in the USA. TBZ acts by reducing dopaminergic input to the striatum. Results In previous studies we demonstrated that long-term feeding with TBZ (combined with L-Dopa) alleviated the motor deficits and reduced the striatal neuronal loss in the yeast artificial chromosome transgenic mouse model of HD (YAC128 mice). To further investigate a potential beneficial effects of TBZ for HD treatment, we here repeated TBZ evaluation in YAC128 mice starting TBZ treatment at 2 months of age ("early" TBZ group) and at 6 months of age ("late" TBZ group). In agreement with our previous studies, we found that both "early" and "late" TBZ treatments alleviated motor deficits and reduced striatal cell loss in YAC128 mice. In addition, we have been able to recapitulate and quantify depression-like symptoms in TBZ-treated mice, reminiscent of common side effects observed in HD patients taking TBZ. Conclusions Our results further support therapeutic value of TBZ for treatment of HD but also highlight the need to develop more specific dopamine antagonists which are less prone to side-effects.
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Affiliation(s)
- Hongyu Wang
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
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31
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Abstract
Huntington's disease (HD) is caused by a CAG repeat expansion in exon 1 of the HD gene resulting in a long polyglutamine tract in the N-terminus of the protein huntingtin. Patients carrying the mutation display chorea in early stages followed by akinesia and sometimes dystonia in late stages. Other major symptoms include depression, anxiety, irritability or aggressive behavior, and apathy. Although many neuronal systems are affected, dysfunction and subsequent neurodegeneration in the basal ganglia and cortex are the most apparent pathologies. In HD, the primary hypothesis has been that there is an initial overactivity of glutamate neurotransmission that produces excitotoxicity followed by a series of complex changes that are different in the striatum and in the cortex. This review will focus on evidence for alterations in dopamine (DA)-glutamate interactions in HD, concentrating on the striatum and cortex. The most recent evidence points to decreases in DA and glutamate neurotransmission as the HD phenotype develops. However, there is some evidence for increased DA and glutamate functions that could be responsible for some of the early HD phenotype. Significant evidence indicates that glutamate and dopamine neurotransmission is affected in HD, compromising the fine balance in which DA modulates glutamate-induced excitation in the basal ganglia and cortex. Restoring the balance between glutamate and dopamine could be helpful to treat HD symptoms.
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Lee JM, Zhang J, Su AI, Walker JR, Wiltshire T, Kang K, Dragileva E, Gillis T, Lopez ET, Boily MJ, Cyr M, Kohane I, Gusella JF, MacDonald ME, Wheeler VC. A novel approach to investigate tissue-specific trinucleotide repeat instability. BMC SYSTEMS BIOLOGY 2010; 4:29. [PMID: 20302627 PMCID: PMC2856555 DOI: 10.1186/1752-0509-4-29] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 03/19/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND In Huntington's disease (HD), an expanded CAG repeat produces characteristic striatal neurodegeneration. Interestingly, the HD CAG repeat, whose length determines age at onset, undergoes tissue-specific somatic instability, predominant in the striatum, suggesting that tissue-specific CAG length changes could modify the disease process. Therefore, understanding the mechanisms underlying the tissue specificity of somatic instability may provide novel routes to therapies. However progress in this area has been hampered by the lack of sensitive high-throughput instability quantification methods and global approaches to identify the underlying factors. RESULTS Here we describe a novel approach to gain insight into the factors responsible for the tissue specificity of somatic instability. Using accurate genetic knock-in mouse models of HD, we developed a reliable, high-throughput method to quantify tissue HD CAG repeat instability and integrated this with genome-wide bioinformatic approaches. Using tissue instability quantified in 16 tissues as a phenotype and tissue microarray gene expression as a predictor, we built a mathematical model and identified a gene expression signature that accurately predicted tissue instability. Using the predictive ability of this signature we found that somatic instability was not a consequence of pathogenesis. In support of this, genetic crosses with models of accelerated neuropathology failed to induce somatic instability. In addition, we searched for genes and pathways that correlated with tissue instability. We found that expression levels of DNA repair genes did not explain the tissue specificity of somatic instability. Instead, our data implicate other pathways, particularly cell cycle, metabolism and neurotransmitter pathways, acting in combination to generate tissue-specific patterns of instability. CONCLUSION Our study clearly demonstrates that multiple tissue factors reflect the level of somatic instability in different tissues. In addition, our quantitative, genome-wide approach is readily applicable to high-throughput assays and opens the door to widespread applications with the potential to accelerate the discovery of drugs that alter tissue instability.
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Affiliation(s)
- Jong-Min Lee
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA.
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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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Deyts C, Galan-Rodriguez B, Martin E, Bouveyron N, Roze E, Charvin D, Caboche J, Bétuing S. Dopamine D2 receptor stimulation potentiates PolyQ-Huntingtin-induced mouse striatal neuron dysfunctions via Rho/ROCK-II activation. PLoS One 2009; 4:e8287. [PMID: 20016831 PMCID: PMC2790370 DOI: 10.1371/journal.pone.0008287] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 11/18/2009] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Huntington's disease (HD) is a polyglutamine-expanded related neurodegenerative disease. Despite the ubiquitous expression of expanded, polyQ-Huntingtin (ExpHtt) in the brain, striatal neurons present a higher susceptibility to the mutation. A commonly admitted hypothesis is that Dopaminergic inputs participate to this vulnerability. We previously showed that D2 receptor stimulation increased aggregate formation and neuronal death induced by ExpHtt in primary striatal neurons in culture, and chronic D2 antagonist treatment protects striatal dysfunctions induced by ExpHtt in a lentiviral-induced model system in vivo. The present work was designed to elucidate the signalling pathways involved, downstream D2 receptor (D2R) stimulation, in striatal vulnerability to ExpHtt. METHODOLOGY/PRINCIPAL FINDINGS Using primary striatal neurons in culture, transfected with a tagged-GFP version of human exon 1 ExpHtt, and siRNAs against D2R or D1R, we confirm that DA potentiates neuronal dysfunctions via D2R but not D1R stimulation. We demonstrate that D2 agonist treatment induces neuritic retraction and growth cone collapse in Htt- and ExpHtt expressing neurons. We then tested a possible involvement of the Rho/ROCK signalling pathway, which plays a key role in the dynamic of the cytoskeleton, in these processes. The pharmacological inhibitors of ROCK (Y27632 and Hydroxyfasudil), as well as siRNAs against ROCK-II, reversed D2-related effects on neuritic retraction and growth cone collapse. We show a coupling between D2 receptor stimulation and Rho activation, as well as hyperphosphorylation of Cofilin, a downstream effector of ROCK-II pathway. Importantly, D2 agonist-mediated potentiation of aggregate formation and neuronal death induced by ExpHtt, was totally reversed by Y27632 and Hydroxyfasudil and ROCK-II siRNAs. CONCLUSIONS/SIGNIFICANCE Our data provide the first demonstration that D2R-induced vulnerability in HD is critically linked to the activation of the Rho/ROCK signalling pathway. The inclusion of Rho/ROCK inhibitors could be an interesting therapeutic option aimed at forestalling the onset of the disease.
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Affiliation(s)
- Carole Deyts
- CNRS UMR 7102, Université Pierre et Marie Curie-Paris 6, Paris, France
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie-Paris 6, Paris, France
- Biological Sciences Division, University of Chicago, Chicago, Illinois, United States of America
| | - Beatriz Galan-Rodriguez
- CNRS UMR 7102, Université Pierre et Marie Curie-Paris 6, Paris, France
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Elodie Martin
- CNRS UMR 7102, Université Pierre et Marie Curie-Paris 6, Paris, France
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Nicolas Bouveyron
- CNRS UMR 7102, Université Pierre et Marie Curie-Paris 6, Paris, France
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Emmanuel Roze
- CNRS UMR 7102, Université Pierre et Marie Curie-Paris 6, Paris, France
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie-Paris 6, Paris, France
- Service de Neurologie, Hôpital Salpêtrière, Assitance Publique-Hôpitaux de Paris, Paris, France
| | - Delphine Charvin
- CNRS UMR 7102, Université Pierre et Marie Curie-Paris 6, Paris, France
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Jocelyne Caboche
- CNRS UMR 7102, Université Pierre et Marie Curie-Paris 6, Paris, France
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Sandrine Bétuing
- CNRS UMR 7102, Université Pierre et Marie Curie-Paris 6, Paris, France
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie-Paris 6, Paris, France
- Université Evry Val d'Essonne, Evry, France
- * E-mail:
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Hyperdopaminergic tone erodes prefrontal long-term potential via a D2 receptor-operated protein phosphatase gate. J Neurosci 2009; 29:14086-99. [PMID: 19906957 DOI: 10.1523/jneurosci.0974-09.2009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Dopamine (DA) plays crucial roles in the cognitive functioning of the prefrontal cortex (PFC), which, to a large degree, depends on lasting neural traces formed in prefrontal networks. The establishment of these permanent traces requires changes in cortical synaptic efficacy. DA, via the D(1)-class receptors, is thought to gate or facilitate synaptic plasticity in the PFC, with little role recognized for the D(2)-class receptors. Here we show that, when significantly elevated, DA erodes, rather than facilitates, the induction of long-term potentiation (LTP) in the PFC by acting at the far less abundant cortical D(2)-class receptors through a dominant coupling to the protein phosphatase 1 (PP1) activity in postsynaptic neurons. In mice with persistently elevated extracellular DA, resulting from inactivation of the DA transporter (DAT) gene, LTP in layer V PFC pyramidal neurons cannot be established, regardless of induction protocols. Acute increase of dopaminergic transmission by DAT blockers or overstimulation of D(2) receptors in normal mice have similar LTP shutoff effects. LTP in mutant mice can be rescued by a single in vivo administration of D(2)-class antagonists. Suppression of postsynaptic PP1 mimics and occludes the D(2)-mediated rescue of LTP in mutant mice and prevents the acute erosion of LTP by D(2) agonists in normal mice. Our studies reveal a mechanistically unique heterosynaptic PP1 gate that is constitutively driven by background DA to influence LTP induction. By blocking prefrontal synaptic plasticity, excessive DA may prevent storage of lasting memory traces in PFC networks and impair executive functions.
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Galvan L, Brouillet E. Rhes, a protein with selective expression in the striatum, plays a major role in Huntington’s disease pathogenesis. FUTURE NEUROLOGY 2009. [DOI: 10.2217/fnl.09.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Evaluation of: Subramaniam S, Sixt KM, Barrow R, Snyder SH: Rhes, a striatal specific protein, mediates mutant-huntingtin cytotoxicity. Science 324, 1327–1330 (2009). Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder characterized by choreiform movements, cognitive deficits and psychiatric disturbances. The disease is caused by an abnormal expansion of a CAG repeat located in exon 1 of the gene encoding the huntingtin protein (Htt). The genetic defect encodes a polyglutamine tract in the N-terminal part of Htt that confers a toxic function to the protein. The most striking neuropathological hallmark in HD patients is the selective atrophy of the striatum. The mechanisms underlying the particular vulnerability of the striatum are unknown. Subramaniam and collaborators demonstrate that the cytotoxicity of mutant Htt is greatly enhanced in the presence of the small GTPase, Rhes, a protein of unclear function that has a preferential expression in the striatum. The study demonstrates that Rhes is an E3 ligase, interacts with mutant Htt and modifies it through SUMOylation, a post-transcriptional process that consists of the addition of the protein SUMO1 to mutant Htt. By contrast, the GTPase activity of Rhes does not seem to be involved in the toxicity of mutant Htt. The Rhes-mediated sumoylation of mutant Htt eventually leads to reduced levels of neuroprotective insoluble aggregates, and increased levels of the toxic soluble form of mutant Htt. These completely novel results shed new light on HD pathogenesis. The selective expression of Rhes in the striatum and its role in mutant Htt toxicity could explain why the striatum is so vulnerable in HD. This work may lead to new therapeutic strategies targeting Rhes.
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Affiliation(s)
- Laurie Galvan
- CEA, DSV, I2BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France and CEA, CNRS URA 2210, F-92265 Fontenay-aux-Roses, France
| | - Emmanuel Brouillet
- CEA, DSV, I2BM, Molecular Imaging Research Center (MIRCen), F-92265 Fontenay-aux-Roses, France and CEA, CNRS URA 2210, F-92265 Fontenay-aux-Roses, France
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Roze E, Betuing S, Deyts C, Vidailhet M, Caboche J. Physiopathologie de la maladie de Huntington : état des connaissances. Rev Neurol (Paris) 2008; 164:977-94. [DOI: 10.1016/j.neurol.2008.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 01/28/2008] [Accepted: 03/26/2008] [Indexed: 12/16/2022]
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Dopaminergic and glutamatergic signaling crosstalk in Huntington's disease neurodegeneration: the role of p25/cyclin-dependent kinase 5. J Neurosci 2008; 28:10090-101. [PMID: 18829967 DOI: 10.1523/jneurosci.3237-08.2008] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Altered glutamatergic and dopaminergic signaling has been proposed as contributing to the specific striatal cell death observed in Huntington's disease (HD). However, the precise mechanisms by which mutant huntingtin sensitize striatal cells to dopamine and glutamate inputs remain unclear. Here, we demonstrate in knock-in HD striatal cells that mutant huntingtin enhances dopamine-mediated striatal cell death via dopamine D(1) receptors. Moreover, we show that NMDA receptors specifically potentiate the vulnerability of mutant huntingtin striatal cells to dopamine toxicity as pretreatment with NMDA increased D(1)R-induced cell death in mutant but not wild-type cells. As potential underlying mechanism of increased striatal vulnerability, we identified aberrant cyclin-dependent kinase 5 (Cdk5) activation. We demonstrate that enhanced Cdk5 phosphorylation and increased calpain-mediated conversion of the Cdk5 activator p35 into p25 may account for the deregulation of Cdk5 associated to dopamine and glutamate receptor activation in knock-in HD striatal cells. Moreover, supporting a detrimental role of Cdk5 in striatal cell death, neuronal loss can be widely prevented by roscovitine, a potent Cdk5 inhibitor. Significantly, reduced Cdk5 expression together with enhanced Cdk5 phosphorylation and p25 accumulation also occurs in the striatum of mutant Hdh(Q111) mice and HD human brain suggesting the relevance of deregulated Cdk5 pathway in HD pathology. These findings provide new insights into the molecular mechanisms underlying the selective vulnerability of striatal cells in HD and identify p25/Cdk5 as an important mediator of dopamine and glutamate neurotoxicity associated to HD.
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Pathophysiology of Huntington's disease: from huntingtin functions to potential treatments. Curr Opin Neurol 2008; 21:497-503. [PMID: 18607213 DOI: 10.1097/wco.0b013e328304b692] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW Drugs used to treat Huntington's disease act on the symptoms but do not slow the disease process itself. This review focuses on recent pathogenetic findings and on emerging therapeutic approaches. RECENT FINDINGS Basic research is providing novel insights into the complex molecular pathways involved in the pathogenesis of Huntington's disease. Several mechanisms have been identified that mediate neuronal dysfunction and death; these include neuronal aggregation of the mutated protein, transcriptional dysregulation, excitotoxicity, altered energy metabolism, impaired axonal transport, and altered synaptic transmission. Recent experimental works have identified potential new therapeutic targets. In particular, they emphasize the role of altered histone modifications in transcriptional dysregulation, the synergistic action of glutamatergic and dopaminergic pathways in inducing excitotoxicity, the neuroprotective effect of brain-derived neurotrophic factor expression and transport restoration, and the possibility of reducing the expression of the mutant protein huntingtin and its deleterious effects by using short interfering mRNAs. SUMMARY Successful neuroprotective therapy for Huntington's disease patients is likely to involve a combined approach targeting both cellular and molecular mediators that account for the toxicity of mutated huntingtin.
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Waugh JL, Miller VS, Chudnow RS, Dowling MM. Juvenile Huntington disease exacerbated by methylphenidate: case report. J Child Neurol 2008; 23:807-9. [PMID: 18658080 DOI: 10.1177/0883073808314152] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The authors describe the case of an 8-year-old boy, otherwise healthy, who presented with symptoms consistent with attention-deficit hyperactivity disorder (ADHD) and was started on a trial of methylphenidate. Within 4 weeks, he experienced a rapid decline in fine motor skills, with dysarthria, intention tremor, motor impersistence, and diffusely increased tone. Symptoms persisted despite cessation of methylphenidate. At that time, a paternal history of Huntington disease was disclosed. Molecular analysis revealed an expansion in CAG repeats to 75 copies, within the range characteristic of juvenile Huntington disease. This report raises the possibility that use of dopaminergic agonists in patients with a family history of Huntington disease may lead to clinical exacerbation of motor symptoms and/or unwitting diagnosis in an unprepared family.
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Affiliation(s)
- Jeff L Waugh
- Department of Pediatrics, Children's Medical Center of Dallas, Texas, USA.
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Robinson P, Lebel M, Cyr M. Dopamine D1 receptor–mediated aggregation of N-terminal fragments of mutant huntingtin and cell death in a neuroblastoma cell line. Neuroscience 2008; 153:762-72. [DOI: 10.1016/j.neuroscience.2008.02.052] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 02/19/2008] [Accepted: 02/23/2008] [Indexed: 10/22/2022]
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Benchoua A, Trioulier Y, Diguet E, Malgorn C, Gaillard MC, Dufour N, Elalouf JM, Krajewski S, Hantraye P, Déglon N, Brouillet E. Dopamine determines the vulnerability of striatal neurons to the N-terminal fragment of mutant huntingtin through the regulation of mitochondrial complex II. Hum Mol Genet 2008; 17:1446-56. [PMID: 18267960 PMCID: PMC2367694 DOI: 10.1093/hmg/ddn033] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In neurodegenerative disorders associated with primary or secondary mitochondrial defects such as Huntington's disease (HD), cells of the striatum are particularly vulnerable to cell death, although the mechanisms by which this cell death is induced are unclear. Dopamine, found in high concentrations in the striatum, may play a role in striatal cell death. We show that in primary striatal cultures, dopamine increases the toxicity of an N-terminal fragment of mutated huntingtin (Htt-171-82Q). Mitochondrial complex II protein (mCII) levels are reduced in HD striatum, indicating that this protein may be important for dopamine-mediated striatal cell death. We found that dopamine enhances the toxicity of the selective mCII inhibitor, 3-nitropropionic acid. We also demonstrated that dopamine doses that are insufficient to produce cell loss regulate mCII expression at the mRNA, protein and catalytic activity level. We also show that dopamine-induced down-regulation of mCII levels can be blocked by several dopamine D2 receptor antagonists. Sustained overexpression of mCII subunits using lentiviral vectors abrogated the effects of dopamine, both by high dopamine concentrations alone and neuronal death induced by low dopamine concentrations together with Htt-171-82Q. This novel pathway links dopamine signaling and regulation of mCII activity and could play a key role in oxidative energy metabolism and explain the vulnerability of the striatum in neurodegenerative diseases.
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Affiliation(s)
- Alexandra Benchoua
- Unité de Recherche Associée, Commissariat à l'Energie Atomique (CEA)-Centre Nationale de la Recherche Scientifique (CNRS) 2210, Service Hospitalier Frédéric Joliot, Orsay Cedex, France
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Unregulated cytosolic dopamine causes neurodegeneration associated with oxidative stress in mice. J Neurosci 2008; 28:425-33. [PMID: 18184785 DOI: 10.1523/jneurosci.3602-07.2008] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The role of dopamine as a vulnerability factor and a toxic agent in Parkinson's disease (PD) is still controversial, yet the presumed dopamine toxicity is partly responsible for the "DOPA-sparing" clinical practice that avoids using L-3,4-dihydroxyphenylalanine (L-DOPA), a dopamine precursor, in early PD. There is a lack of studies on animal models that directly isolate dopamine as one determining factor in causing neurodegeneration. To address this, we have generated a novel transgenic mouse model in which striatal neurons are engineered to take up extracellular dopamine without acquiring regulatory mechanisms found in dopamine neurons. These mice developed motor dysfunctions and progressive neurodegeneration in the striatum within weeks. The neurodegeneration was accompanied by oxidative stress, evidenced by substantial oxidative protein modifications and decrease in glutathione. Ultrastructural morphologies of degenerative cells suggest necrotic neurodegeneration. Moreover, L-DOPA accelerated neurodegeneration and worsened motor dysfunction. In contrast, reducing dopamine input to striatum by lesioning the medial forebrain bundle attenuated motor dysfunction. These data suggest that pathology in genetically modified striatal neurons depends on their dopamine supply. These neurons were also supersensitive to neurotoxin. A very low dose of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (5 mg/kg) caused profound neurodegeneration of striatal neurons, but not midbrain dopamine neurons. Our results provide the first in vivo evidence that chronic exposure to unregulated cytosolic dopamine alone is sufficient to cause neurodegeneration. The present study has significant clinical implications, because dopamine replacement therapy is the mainstay of PD treatment. In addition, our model provides an efficient in vivo approach to test therapeutic agents for PD.
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Dopamine transporter mutant mice in experimental neuropharmacology. Naunyn Schmiedebergs Arch Pharmacol 2007; 377:301-13. [PMID: 18057916 DOI: 10.1007/s00210-007-0216-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 11/02/2007] [Indexed: 12/27/2022]
Abstract
An opportunity to perform targeted genetic manipulations in mice has provided another dimension for modern pharmacological research. Genetically modified mice have become important tools to investigate functions of previously unexplored proteins, define mechanism of action of new and known pharmacological drugs, and validate novel targets for treatment of human disorders. One of the best examples of such use of genetic models in experimental pharmacology represents investigations involving mice deficient in the gene encoding the dopamine transporter (DAT). The dopamine transporter tightly regulates the extracellular dynamics of dopamine by recapturing released neurotransmitter into the presynaptic terminals, and genetic deletion of this protein results in profound alterations in both the presynaptic homeostasis and the extracellular dynamics of dopamine. By using this model of severe dopaminergic dysregulation, significant progress has been made in defining the major target of psychotropic drugs, understanding the mechanisms of their action, unraveling novel signaling events relevant for dopaminergic transmission, and mapping neuronal pathways involved in dopamine-related behaviors. Furthermore, DAT mutant mice provided an opportunity to model in vivo conditions of extreme dopaminergic dysfunction that could be relevant for human disorders such as ADHD, schizophrenia, and Parkinson's disease and, thus, could serve as test systems for developing novel treatments for these and related disorders.
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Tang TS, Chen X, Liu J, Bezprozvanny I. Dopaminergic signaling and striatal neurodegeneration in Huntington's disease. J Neurosci 2007; 27:7899-910. [PMID: 17652581 PMCID: PMC3307545 DOI: 10.1523/jneurosci.1396-07.2007] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by polyglutamine (polyQ) expansion in Huntingtin protein (Htt). PolyQ expansion in Htt(exp) causes selective degeneration of striatal medium spiny neurons (MSNs) in HD patients. Striatal MSN neurons receive glutamatergic input from the cortex and dopaminergic input from the substantia nigra. In previous studies with the yeast artificial chromosome (YAC128) transgenic HD mouse model, we established a connection between glutamate receptor activation, disturbed calcium (Ca2+) signaling, and apoptosis of HD MSNs (Tang et al., 2005). Here, we used the same YAC128 mouse model to investigate the role of dopaminergic signaling in HD. We discovered that glutamate and dopamine signaling pathways act synergistically to induce elevated Ca2+ signals and to cause apoptosis of YAC128 MSNs in vitro. We demonstrated that potentiating effects of dopamine are mediated by D1-class dopamine receptors (DARs) and not by D2-class DARs. Consistent with in vitro findings, in whole-animal experiments we found that persistent elevation of striatal dopamine levels exacerbated the behavioral motor deficits and MSN neurodegeneration in YAC128 mice. We further discovered that the clinically relevant dopamine pathway inhibitor tetrabenazine alleviated the motor deficits and reduced striatal cell loss in YAC128 mice. Our results suggest that dopamine signaling pathway plays an important role in HD pathogenesis and that antagonists of dopamine pathway such as tetrabenazine or dopamine receptor blockers may have a therapeutic potential for treatment of HD beyond well established "symptomatic" benefit.
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Affiliation(s)
- Tie-Shan Tang
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Xi Chen
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Jing Liu
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Ilya Bezprozvanny
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
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Charvin D, Roze E, Perrin V, Deyts C, Betuing S, Pagès C, Régulier E, Luthi-Carter R, Brouillet E, Déglon N, Caboche J. Haloperidol protects striatal neurons from dysfunction induced by mutated huntingtin in vivo. Neurobiol Dis 2007; 29:22-9. [PMID: 17905594 DOI: 10.1016/j.nbd.2007.07.028] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 07/16/2007] [Accepted: 07/23/2007] [Indexed: 11/28/2022] Open
Abstract
Huntington's disease (HD) results from an abnormal polyglutamine extension in the N-terminal region of the huntingtin protein. This mutation causes preferential degeneration of striatal projection neurons. We previously demonstrated, in vitro, that dopaminergic D2 receptor stimulation acted synergistically with mutated huntingtin (expHtt) to increase aggregate formation and striatal death. In the present work, we extend these observations to an in vivo system based on lentiviral-mediated expression of expHtt in the rat striatum. The early and chronic treatment with the D2 antagonist haloperidol decanoate protects striatal neurons from expHtt-induced dysfunction, as analyzed by DARPP-32 and NeuN stainings. Haloperidol treatment also reduces aggregates formation, an effect that is maintained over time. These findings indicate that D2 receptors activation contributes to the deleterious effects of expHtt on striatal function and may represent an interesting early target to alter the subsequent course of neuropathology in HD.
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Affiliation(s)
- Delphine Charvin
- Signalisation Neuronale et Régulations Géniques, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, UMR 7102, 9 quai Saint Bernard, 75005 Paris, France
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