1
|
Chang KH, Cheng ML, Tang HY, Lin CY, Chen CM. Dysregulation of choline metabolism and therapeutic potential of citicoline in Huntington's disease. Aging Cell 2024:e14302. [PMID: 39143698 DOI: 10.1111/acel.14302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 07/11/2024] [Accepted: 07/18/2024] [Indexed: 08/16/2024] Open
Abstract
Huntington's disease (HD) is associated with dysregulated choline metabolism, but the underlying mechanisms remain unclear. This study investigated the expression of key enzymes in this pathway in R6/2 HD mice and human HD postmortem brain tissues. We further explored the therapeutic potential of modulating choline metabolism for HD. Both R6/2 mice and HD patients exhibited reduced expression of glycerophosphocholine phosphodiesterase 1 (GPCPD1), a key enzyme in choline metabolism, in the striatum and cortex. The striatum of R6/2 mice also showed decreased choline and phosphorylcholine, and increased glycerophosphocholine, suggesting disruption in choline metabolism due to GPCPD1 deficiency. Treatment with citicoline significantly improved motor performance, upregulated anti-apoptotic Bcl2 expression, and reduced oxidative stress marker malondialdehyde in both brain regions. Metabolomic analysis revealed partial restoration of disrupted metabolic patterns in the striatum and cortex following citicoline treatment. These findings strongly suggest the role of GPCPD1 deficiency in choline metabolism dysregulation in HD. The therapeutic potential of citicoline in R6/2 mice highlights the choline metabolic pathway as a promising target for future HD therapies.
Collapse
Affiliation(s)
- Kuo-Hsuan Chang
- Department of Neurology, Chang Gung Memorial Hospital-Linkou Medical Center, Chang Gung University School of Medicine, Taoyuan, Taiwan
| | - Mei-Ling Cheng
- Department of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
- Metabolomics Core Laboratory, Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
- Clinical Metabolomics Core Core Laboratory, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Hsiang-Yu Tang
- Metabolomics Core Laboratory, Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Chung-Yin Lin
- Department of Neurology, Chang Gung Memorial Hospital-Linkou Medical Center, Chang Gung University School of Medicine, Taoyuan, Taiwan
- Institute for Radiological Research, Chang Gung University, Taoyuan, Taiwan
| | - Chiung-Mei Chen
- Department of Neurology, Chang Gung Memorial Hospital-Linkou Medical Center, Chang Gung University School of Medicine, Taoyuan, Taiwan
| |
Collapse
|
2
|
Zhang Q, Li T, Xu M, Islam B, Wang J. Application of Optogenetics in Neurodegenerative Diseases. Cell Mol Neurobiol 2024; 44:57. [PMID: 39060759 PMCID: PMC11281982 DOI: 10.1007/s10571-024-01486-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 06/15/2024] [Indexed: 07/28/2024]
Abstract
Optogenetics, a revolutionary technique integrating optical and genetic methodologies, offers unparalleled precision in spatial targeting and temporal resolution for cellular control. This approach enables the selective manipulation of specific neuronal populations, inducing subtle electrical changes that significantly impact complex neural circuitry. As optogenetics precisely targets and modulates neuronal activity, it holds the potential for significant breakthroughs in understanding and potentially altering the course of neurodegenerative diseases, characterized by selective neuronal loss leading to functional deficits within the nervous system. The integration of optogenetics into neurodegenerative disease research has significantly advanced in the field, offering new insights and paving the way for innovative treatment strategies. Its application in clinical settings, although still in the nascent stages, suggests a promising future for addressing some of the most challenging aspects of neurodegenerative disorders. In this review, we provide a comprehensive overview of these research undertakings.
Collapse
Affiliation(s)
- Qian Zhang
- Xiangya School of Public Health, Central South University, Changsha, 410078, Hunan, People's Republic of China
| | - Tianjiao Li
- Xiangya School of Public Health, Central South University, Changsha, 410078, Hunan, People's Republic of China
| | - Mengying Xu
- Xiangya School of Public Health, Central South University, Changsha, 410078, Hunan, People's Republic of China
| | - Binish Islam
- Xiangya School of Public Health, Central South University, Changsha, 410078, Hunan, People's Republic of China
| | - Jianwu Wang
- Xiangya School of Public Health, Central South University, Changsha, 410078, Hunan, People's Republic of China.
| |
Collapse
|
3
|
Holley SM, Reidling JC, Cepeda C, Wu J, Lim RG, Lau A, Moore C, Miramontes R, Fury B, Orellana I, Neel M, Coleal-Bergum D, Monuki ES, Bauer G, Meshul CK, Levine MS, Thompson LM. Transplanted human neural stem cells rescue phenotypes in zQ175 Huntington's disease mice and innervate the striatum. Mol Ther 2023; 31:3545-3563. [PMID: 37807512 PMCID: PMC10727970 DOI: 10.1016/j.ymthe.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/28/2023] [Accepted: 10/04/2023] [Indexed: 10/10/2023] Open
Abstract
Huntington's disease (HD), a genetic neurodegenerative disorder, primarily affects the striatum and cortex with progressive loss of medium-sized spiny neurons (MSNs) and pyramidal neurons, disrupting cortico-striatal circuitry. A promising regenerative therapeutic strategy of transplanting human neural stem cells (hNSCs) is challenged by the need for long-term functional integration. We previously described that, with short-term hNSC transplantation into the striatum of HD R6/2 mice, human cells differentiated into electrophysiologically active immature neurons, improving behavior and biochemical deficits. Here, we show that long-term (8 months) implantation of hNSCs into the striatum of HD zQ175 mice ameliorates behavioral deficits, increases brain-derived neurotrophic factor (BDNF) levels, and reduces mutant huntingtin (mHTT) accumulation. Patch clamp recordings, immunohistochemistry, single-nucleus RNA sequencing (RNA-seq), and electron microscopy demonstrate that hNSCs differentiate into diverse neuronal populations, including MSN- and interneuron-like cells, and form connections. Single-nucleus RNA-seq analysis also shows restoration of several mHTT-mediated transcriptional changes of endogenous striatal HD mouse cells. Remarkably, engrafted cells receive synaptic inputs, innervate host neurons, and improve membrane and synaptic properties. Overall, the findings support hNSC transplantation for further evaluation and clinical development for HD.
Collapse
Affiliation(s)
- Sandra M Holley
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jack C Reidling
- Institute for Memory Impairment and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jie Wu
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Ryan G Lim
- Institute for Memory Impairment and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Alice Lau
- Psychiatry & Human Behavior, University of California Irvine, Irvine, CA 92697, USA
| | - Cindy Moore
- Portland VA Medical Center, Portland, OR 97239, USA
| | - Ricardo Miramontes
- Institute for Memory Impairment and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Brian Fury
- Institute for Regenerative Cures, University of California Davis, Sacramento, CA 95817, USA
| | - Iliana Orellana
- Institute for Memory Impairment and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Michael Neel
- Department of Pathology & Laboratory Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Dane Coleal-Bergum
- Institute for Regenerative Cures, University of California Davis, Sacramento, CA 95817, USA
| | - Edwin S Monuki
- Department of Pathology & Laboratory Medicine, University of California, Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Center, University of California Irvine, Irvine, CA 92697, USA
| | - Gerhard Bauer
- Institute for Regenerative Cures, University of California Davis, Sacramento, CA 95817, USA
| | - Charles K Meshul
- Portland VA Medical Center, Portland, OR 97239, USA; Oregon Health & Science University, Department of Behavioral Neuroscience and Pathology, Portland, OR 97239, USA
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA; Brain Research Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Leslie M Thompson
- Institute for Memory Impairment and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA; Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA; Psychiatry & Human Behavior, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Center, University of California Irvine, Irvine, CA 92697, USA; Department of Neurobiology & Behavior University of California Irvine, Irvine, CA 92697, USA.
| |
Collapse
|
4
|
Somatostatin and Somatostatin-Containing Interneurons—From Plasticity to Pathology. Biomolecules 2022; 12:biom12020312. [PMID: 35204812 PMCID: PMC8869243 DOI: 10.3390/biom12020312] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/27/2022] [Accepted: 02/11/2022] [Indexed: 01/27/2023] Open
Abstract
Despite the obvious differences in the pathophysiology of distinct neuropsychiatric diseases or neurodegenerative disorders, some of them share some general but pivotal mechanisms, one of which is the disruption of excitation/inhibition balance. Such an imbalance can be generated by changes in the inhibitory system, very often mediated by somatostatin-containing interneurons (SOM-INs). In physiology, this group of inhibitory interneurons, as well as somatostatin itself, profoundly shapes the brain activity, thus influencing the behavior and plasticity; however, the changes in the number, density and activity of SOM-INs or levels of somatostatin are found throughout many neuropsychiatric and neurological conditions, both in patients and animal models. Here, we (1) briefly describe the brain somatostatinergic system, characterizing the neuropeptide somatostatin itself, its receptors and functions, as well the physiology and circuitry of SOM-INs; and (2) summarize the effects of the activity of somatostatin and SOM-INs in both physiological brain processes and pathological brain conditions, focusing primarily on learning-induced plasticity and encompassing selected neuropsychological and neurodegenerative disorders, respectively. The presented data indicate the somatostatinergic-system-mediated inhibition as a substantial factor in the mechanisms of neuroplasticity, often disrupted in a plethora of brain pathologies.
Collapse
|
5
|
Huang L, Fang L, Liu Q, Torshizi AD, Wang K. Integrated analysis on transcriptome and behaviors defines HTT repeat-dependent network modules in Huntington's disease. Genes Dis 2021; 9:479-493. [PMID: 35224162 PMCID: PMC8843892 DOI: 10.1016/j.gendis.2021.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/13/2021] [Accepted: 05/12/2021] [Indexed: 01/02/2023] Open
Abstract
Huntington's disease (HD) is caused by a CAG repeat expansion in the huntingtin (HTT) gene. Knock-in mice carrying a CAG repeat-expanded Htt will develop HD phenotypes. Previous studies suggested dysregulated molecular networks in a CAG length genotype- and the age-dependent manner in brain tissues from knock-in mice carrying expanded Htt CAG repeats. Furthermore, a large-scale phenome analysis defined a behavioral signature for HD genotype in knock-in mice carrying expanded Htt CAG repeats. However, an integrated analysis correlating phenotype features with genotypes (CAG repeat expansions) was not conducted previously. In this study, we revealed the landscape of the behavioral features and gene expression correlations based on 445 mRNA samples and 445 microRNA samples, together with behavioral features (396 PhenoCube behaviors and 111 NeuroCube behaviors) in Htt CAG-knock-in mice. We identified 37 behavioral features that were significantly associated with CAG repeat length including the number of steps and hind limb stand duration. The behavioral features were associated with several gene coexpression groups involved in neuronal dysfunctions, which were also supported by the single-cell RNA sequencing data in the striatum and the spatial gene expression in the brain. We also identified 15 chemicals with significant responses for genes with enriched behavioral features, most of them are agonist or antagonist for dopamine receptors and serotonin receptors used for neurology/psychiatry. Our study provides further evidence that abnormal neuronal signal transduction in the striatum plays an important role in causing HD-related phenotypic behaviors and provided rich information for the further pharmacotherapeutic intervention possibility for HD.
Collapse
Affiliation(s)
- Lulin Huang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province, Department of Clinical Laboratory, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, PR China
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Corresponding author. The Key Laboratory for Human Disease Gene Study of Sichuan Province, Department of Clinical Laboratory, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, PR China.
| | - Li Fang
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Qian Liu
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Abolfazl Doostparast Torshizi
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kai Wang
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Corresponding author.
| |
Collapse
|
6
|
Rallapalle V, King AC, Gray M. BACHD Mice Recapitulate the Striatal Parvalbuminergic Interneuron Loss Found in Huntington's Disease. Front Neuroanat 2021; 15:673177. [PMID: 34108866 PMCID: PMC8180558 DOI: 10.3389/fnana.2021.673177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/23/2021] [Indexed: 11/29/2022] Open
Abstract
Huntington’s disease (HD) is a dominantly inherited, adult-onset neurodegenerative disease characterized by motor, psychiatric, and cognitive abnormalities. Neurodegeneration is prominently observed in the striatum where GABAergic medium spiny neurons (MSN) are the most affected neuronal population. Interestingly, recent reports of pathological changes in HD patient striatal tissue have identified a significant reduction in the number of parvalbumin-expressing interneurons which becomes more robust in tissues of higher disease grade. Analysis of other interneuron populations, including somatostatin, calretinin, and cholinergic, did not reveal significant neurodegeneration. Electrophysiological experiments in BACHD mice have identified significant changes in the properties of parvalbumin and somatostatin expressing interneurons in the striatum. Furthermore, their interactions with MSNs are altered as the mHTT expressing mouse models age with increased input onto MSNs from striatal somatostatin and parvalbumin-expressing neurons. In order to determine whether BACHD mice recapitulate the alterations in striatal interneuron number as observed in HD patients, we analyzed the number of striatal parvalbumin, somatostatin, calretinin, and choline acetyltransferase positive cells in symptomatic 12–14 month-old mice by immunofluorescent labeling. We observed a significant decrease in the number of parvalbumin-expressing interneurons as well as a decrease in the area and perimeter of these cells. No significant changes were observed for somatostatin, calretinin, or cholinergic interneuron numbers while a significant decrease was observed for the area of cholinergic interneurons. Thus, the BACHD mice recapitulate the degenerative phenotype observed in the parvalbumin interneurons in HD patient striata without affecting the number of other interneuron populations in the striatum.
Collapse
Affiliation(s)
- Vyshnavi Rallapalle
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics (CNET), University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Clinical and Diagnostic Sciences, Undergraduate Biomedical Sciences Program, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Annesha C King
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics (CNET), University of Alabama at Birmingham, Birmingham, AL, United States.,Graduate Biomedical Sciences, Neuroscience Theme, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Michelle Gray
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics (CNET), University of Alabama at Birmingham, Birmingham, AL, United States
| |
Collapse
|
7
|
Deng Y, Wang H, Joni M, Sekhri R, Reiner A. Progression of basal ganglia pathology in heterozygous Q175 knock-in Huntington's disease mice. J Comp Neurol 2021; 529:1327-1371. [PMID: 32869871 PMCID: PMC8049038 DOI: 10.1002/cne.25023] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/07/2020] [Accepted: 08/26/2020] [Indexed: 12/29/2022]
Abstract
We used behavioral testing and morphological methods to detail the progression of basal ganglia neuron type-specific pathology and the deficits stemming from them in male heterozygous Q175 mice, compared to age-matched WT males. A rotarod deficit was not present in Q175 mice until 18 months, but increased open field turn rate (reflecting hyperkinesia) and open field anxiety were evident at 6 months. No loss of striatal neurons was seen out to 18 months, but ENK+ and DARPP32+ striatal perikarya were fewer by 6 months, due to diminished expression, with further decline by 18 months. No reduction in SP+ striatal perikarya or striatal interneurons was seen in Q175 mice at 18 months, but cholinergic interneurons showed dendrite attenuation by 6 months. Despite reduced ENK expression in indirect pathway striatal perikarya, ENK-immunostained terminals in globus pallidus externus (GPe) were more abundant at 6 months and remained so out to 18 months. Similarly, SP-immunostained terminals from striatal direct pathway neurons were more abundant in globus pallidus internus and substantia nigra at 6 months and remained so at 18 months. FoxP2+ arkypallidal GPe neurons and subthalamic nucleus neurons were lost by 18 months but not prototypical PARV+ GPe neurons or dopaminergic nigral neurons. Our results show that striatal projection neuron abnormalities and behavioral abnormalities reflecting them develop between 2 and 6 months of age in Q175 male heterozygotes, indicating early effects of the HD mutation. The striatal pathologies resemble those in human HD, but are less severe at 18 months than even in premanifest HD.
Collapse
Affiliation(s)
- Yunping Deng
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Hongbing Wang
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Marion Joni
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Radhika Sekhri
- Department of PathologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Anton Reiner
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
- Department of OphthalmologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| |
Collapse
|
8
|
Poppi LA, Ho-Nguyen KT, Shi A, Daut CT, Tischfield MA. Recurrent Implication of Striatal Cholinergic Interneurons in a Range of Neurodevelopmental, Neurodegenerative, and Neuropsychiatric Disorders. Cells 2021; 10:907. [PMID: 33920757 PMCID: PMC8071147 DOI: 10.3390/cells10040907] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/03/2021] [Accepted: 04/12/2021] [Indexed: 12/17/2022] Open
Abstract
Cholinergic interneurons are "gatekeepers" for striatal circuitry and play pivotal roles in attention, goal-directed actions, habit formation, and behavioral flexibility. Accordingly, perturbations to striatal cholinergic interneurons have been associated with many neurodevelopmental, neurodegenerative, and neuropsychiatric disorders. The role of acetylcholine in many of these disorders is well known, but the use of drugs targeting cholinergic systems fell out of favor due to adverse side effects and the introduction of other broadly acting compounds. However, in response to recent findings, re-examining the mechanisms of cholinergic interneuron dysfunction may reveal key insights into underlying pathogeneses. Here, we provide an update on striatal cholinergic interneuron function, connectivity, and their putative involvement in several disorders. In doing so, we aim to spotlight recurring physiological themes, circuits, and mechanisms that can be investigated in future studies using new tools and approaches.
Collapse
Affiliation(s)
- Lauren A. Poppi
- Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA;
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA; (K.T.H.-N.); (A.S.); (C.T.D.)
- Tourette International Collaborative (TIC) Genetics Study, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Khue Tu Ho-Nguyen
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA; (K.T.H.-N.); (A.S.); (C.T.D.)
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Anna Shi
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA; (K.T.H.-N.); (A.S.); (C.T.D.)
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Cynthia T. Daut
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA; (K.T.H.-N.); (A.S.); (C.T.D.)
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Max A. Tischfield
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA; (K.T.H.-N.); (A.S.); (C.T.D.)
- Tourette International Collaborative (TIC) Genetics Study, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| |
Collapse
|
9
|
Assous M. Striatal cholinergic transmission. Focus on nicotinic receptors' influence in striatal circuits. Eur J Neurosci 2021; 53:2421-2442. [PMID: 33529401 PMCID: PMC8161166 DOI: 10.1111/ejn.15135] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 12/11/2022]
Abstract
The critical role of acetylcholine (ACh) in the basal ganglia is evident from the effect of cholinergic agents in patients suffering from several related neurological disorders, such as Parkinson's disease, Tourette syndrome, or dystonia. The striatum possesses the highest density of ACh markers in the basal ganglia underlying the importance of ACh in this structure. Striatal cholinergic interneurons (CINs) are responsible for the bulk of striatal ACh, although extrinsic cholinergic afferents from brainstem structures may also play a role. CINs are tonically active, and synchronized pause in their activity occurs following the presentation of salient stimuli during behavioral conditioning. However, the synaptic mechanisms involved are not fully understood in this physiological response. ACh modulates striatal circuits by acting on muscarinic and nicotinic receptors existing in several combinations both presynaptically and postsynaptically. While the effects of ACh in the striatum through muscarinic receptors have received particular attention, nicotinic receptors function has been less studied. Here, after briefly reviewing relevant results regarding muscarinic receptors expression and function, I will focus on striatal nicotinic receptor expressed presynaptically on glutamatergic and dopaminergic afferents and postsynaptically on diverse striatal interneurons populations. I will also review recent evidence suggesting the involvement of different GABAergic sources in two distinct nicotinic-receptor-mediated striatal circuits: the disynaptic inhibition of striatal projection neurons and the recurrent inhibition among CINs. A better understanding of striatal nicotinic receptors expression and function may help to develop targeted pharmacological interventions to treat brain disorders such as Parkinson's disease, Tourette syndrome, dystonia, or nicotine addiction.
Collapse
Affiliation(s)
- Maxime Assous
- Center for Molecular and Behavioral Neuroscience, Rutgers, the State University of New Jersey, Newark, NJ, USA
| |
Collapse
|
10
|
Song YH, Yoon J, Lee SH. The role of neuropeptide somatostatin in the brain and its application in treating neurological disorders. Exp Mol Med 2021; 53:328-338. [PMID: 33742131 PMCID: PMC8080805 DOI: 10.1038/s12276-021-00580-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/23/2021] [Accepted: 01/25/2021] [Indexed: 02/07/2023] Open
Abstract
Somatostatin (SST) is a well-known neuropeptide that is expressed throughout the brain. In the cortex, SST is expressed in a subset of GABAergic neurons and is known as a protein marker of inhibitory interneurons. Recent studies have identified the key functions of SST in modulating cortical circuits in the brain and cognitive function. Furthermore, reduced expression of SST is a hallmark of various neurological disorders, including Alzheimer's disease and depression. In this review, we summarize the current knowledge on SST expression and function in the brain. In particular, we describe the physiological roles of SST-positive interneurons in the cortex. We further describe the causal relationship between pathophysiological changes in SST function and various neurological disorders, such as Alzheimer's disease. Finally, we discuss potential treatments and possibility of novel drug developments for neurological disorders based on the current knowledge on the function of SST and SST analogs in the brain derived from experimental and clinical studies.
Collapse
Affiliation(s)
- You-Hyang Song
- grid.37172.300000 0001 2292 0500Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 Republic of Korea
| | - Jiwon Yoon
- grid.37172.300000 0001 2292 0500Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 Republic of Korea
| | - Seung-Hee Lee
- grid.37172.300000 0001 2292 0500Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 Republic of Korea
| |
Collapse
|
11
|
Lim SAO, Surmeier DJ. Enhanced GABAergic Inhibition of Cholinergic Interneurons in the zQ175 +/- Mouse Model of Huntington's Disease. Front Syst Neurosci 2021; 14:626412. [PMID: 33551760 PMCID: PMC7854471 DOI: 10.3389/fnsys.2020.626412] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 12/22/2020] [Indexed: 01/16/2023] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that initially manifests itself in the striatum. How intrastriatal circuitry is altered by the disease is poorly understood. To help fill this gap, the circuitry linking spiny projection neurons (SPNs) to cholinergic interneurons (ChIs) was examined using electrophysiological and optogenetic approaches in ex vivo brain slices from wildtype mice and zQ175+/− models of HD. These studies revealed a severalfold enhancement of GABAergic inhibition of ChIs mediated by collaterals of indirect pathway SPNs (iSPNs), but not direct pathway SPNs (dSPNs). This cell-specific alteration in synaptic transmission appeared in parallel with the emergence of motor symptoms in the zQ175+/− model. The adaptation had a presynaptic locus, as it was accompanied by a reduction in paired-pulse ratio but not in the postsynaptic response to GABA. The alterations in striatal GABAergic signaling disrupted spontaneous ChI activity, potentially contributing to the network dysfunction underlying the hyperkinetic phase of HD.
Collapse
Affiliation(s)
- Sean Austin O Lim
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Neuroscience Program, College of Science and Health, DePaul University, Chicago, IL, United States
| | - D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| |
Collapse
|
12
|
Cepeda C, Levine MS. Synaptic Dysfunction in Huntington's Disease: Lessons from Genetic Animal Models. Neuroscientist 2020; 28:20-40. [PMID: 33198566 DOI: 10.1177/1073858420972662] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The understanding of the functional and structural changes occurring in the cerebral cortex and basal ganglia in Huntington's disease (HD) has benefited considerably from the generation of genetic animal models. Most studies of synaptic alterations in HD models have focused on the striatum, but a more complete picture of synaptic dysfunction in the cortico-basal ganglia-cortical loop is emerging. Here, we provide a review and analysis of current developments in the study of synaptic alterations in these areas using HD rodent models. Recent evidence indicates that cortical maldevelopment plays a role in synaptic dysfunction along the corticostriatal pathway that may have its roots in the way mutant huntingtin interacts with synaptic proteins. Furthermore, a progressive disconnection in the corticostriatal pathway leads to abnormal function engaging extrasynaptic N-methyl-D-aspartate glutamate receptors that contribute to eventual cell degeneration. In addition, biphasic increases followed by decreases in glutamate and dopamine release in the striatum could explain contrasting symptomatology in early and late stages of the disease. Changes in striatal output regions also are beginning to be examined. Finally, we highlight some therapeutic avenues aimed at rescuing synaptic dysfunction.
Collapse
Affiliation(s)
- Carlos Cepeda
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Michael S Levine
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| |
Collapse
|
13
|
Barry J, Sarafian TA, Watson JB, Cepeda C, Levine MS. Mechanisms underlying the enhancement of γ-aminobutyric acid responses in the external globus pallidus of R6/2 Huntington's disease model mice. J Neurosci Res 2020; 98:2349-2356. [PMID: 32856336 DOI: 10.1002/jnr.24710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 07/19/2020] [Accepted: 07/22/2020] [Indexed: 02/06/2023]
Abstract
In Huntington's disease (HD), the output of striatal indirect pathway medium-sized spiny neurons (MSNs) is altered in its target region, the external globus pallidus (GPe). In a previous study we demonstrated that selective optogenetic stimulation of indirect pathway MSNs induced prolonged decay time of γ-aminobutyric acid (GABA) responses in GPe neurons. Here we identified the mechanism underlying this alteration. Electrophysiological recordings in slices from symptomatic R6/2 and wildtype (WT) mice were used to evaluate, primarily, the effects of GABA transporter (GAT) antagonists on responses evoked by optogenetic activation of indirect pathway MSNs. In addition, immunohistochemistry (IHC) and Western blots (WBs) were used to examine GAT-3 expression in HD and WT mice. A GAT-3 blocker (SNAP5114) increased decay time of GABA responses in WT and HD GPe neurons, but the effect was significantly greater in WT neurons. In contrast, a GAT-1 antagonist (NO-711) or a GABAB receptor antagonist (CGP 54626) produced small increases in decay time but no differential effects between genotypes. IHC and WBs showed reduction of GAT-3 expression in the GPe of HD mice. Thus, reduced expression or dysfunction of GAT-3 could underlie alterations of GPe responses to GABA inputs from striatum and could be a target for therapeutic intervention.
Collapse
Affiliation(s)
- Joshua Barry
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Theodore A Sarafian
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Joseph B Watson
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Carlos Cepeda
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Michael S Levine
- IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| |
Collapse
|
14
|
Blumenstock S, Dudanova I. Cortical and Striatal Circuits in Huntington's Disease. Front Neurosci 2020; 14:82. [PMID: 32116525 PMCID: PMC7025546 DOI: 10.3389/fnins.2020.00082] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/21/2020] [Indexed: 12/28/2022] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disorder that typically manifests in midlife with motor, cognitive, and/or psychiatric symptoms. The disease is caused by a CAG triplet expansion in exon 1 of the huntingtin gene and leads to a severe neurodegeneration in the striatum and cortex. Classical electrophysiological studies in genetic HD mouse models provided important insights into the disbalance of excitatory, inhibitory and neuromodulatory inputs, as well as progressive disconnection between the cortex and striatum. However, the involvement of local cortical and striatal microcircuits still remains largely unexplored. Here we review the progress in understanding HD-related impairments in the cortical and basal ganglia circuits, and outline new opportunities that have opened with the development of modern circuit analysis methods. In particular, in vivo imaging studies in mouse HD models have demonstrated early structural and functional disturbances within the cortical network, and optogenetic manipulations of striatal cell types have started uncovering the causal roles of certain neuronal populations in disease pathogenesis. In addition, the important contribution of astrocytes to HD-related circuit defects has recently been recognized. In parallel, unbiased systems biology studies are providing insights into the possible molecular underpinnings of these functional defects at the level of synaptic signaling and neurotransmitter metabolism. With these approaches, we can now reach a deeper understanding of circuit-based HD mechanisms, which will be crucial for the development of effective and targeted therapeutic strategies.
Collapse
Affiliation(s)
- Sonja Blumenstock
- Department of Molecules – Signaling – Development, Max Planck Institute of Neurobiology, Martinsried, Germany
- Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Irina Dudanova
- Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| |
Collapse
|
15
|
Assous M. Emergence of novel functions in striatal low‐threshold spike interneurons (Commentary on Gazan et al., 2019). Eur J Neurosci 2020; 52:3490-3492. [DOI: 10.1111/ejn.14663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/04/2019] [Accepted: 12/19/2019] [Indexed: 01/04/2023]
Affiliation(s)
- Maxime Assous
- Center for Molecular and Behavioral Neuroscience Rutgers University Newark NJ USA
| |
Collapse
|
16
|
McKinley JW, Shi Z, Kawikova I, Hur M, Bamford IJ, Sudarsana Devi SP, Vahedipour A, Darvas M, Bamford NS. Dopamine Deficiency Reduces Striatal Cholinergic Interneuron Function in Models of Parkinson's Disease. Neuron 2019; 103:1056-1072.e6. [PMID: 31324539 DOI: 10.1016/j.neuron.2019.06.013] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 03/12/2019] [Accepted: 06/18/2019] [Indexed: 11/30/2022]
Abstract
Motor and cognitive functions depend on the coordinated interactions between dopamine (DA) and acetylcholine (ACh) at striatal synapses. Increased ACh availability was assumed to accompany DA deficiency based on the outcome of pharmacological treatments and measurements in animals that were critically depleted of DA. Using Slc6a3DTR/+ diphtheria-toxin-sensitive mice, we demonstrate that a progressive and L-dopa-responsive DA deficiency reduces ACh availability and the transcription of hyperpolarization-activated cation (HCN) channels that encode the spike timing of ACh-releasing tonically active striatal interneurons (ChIs). Although the production and release of ACh and DA are reduced, the preponderance of ACh over DA contributes to the motor deficit. The increase in striatal ACh relative to DA is heightened via D1-type DA receptors that activate ChIs in response to DA release from residual axons. These results suggest that stabilizing the expression of HCN channels may improve ACh-DA reciprocity and motor function in Parkinson's disease (PD). VIDEO ABSTRACT.
Collapse
Affiliation(s)
| | - Ziqing Shi
- Department of Pediatrics, Yale University, New Haven, CT 06510, USA
| | - Ivana Kawikova
- Department of Pediatrics, Yale University, New Haven, CT 06510, USA
| | - Matthew Hur
- Department of Pediatrics, Yale University, New Haven, CT 06510, USA
| | - Ian J Bamford
- Department of Pediatrics, Yale University, New Haven, CT 06510, USA
| | | | - Annie Vahedipour
- Department of Pediatrics, Yale University, New Haven, CT 06510, USA
| | - Martin Darvas
- Department of Pathology, University of Washington, Seattle, WA 98105, USA
| | - Nigel S Bamford
- Department of Pediatrics, Yale University, New Haven, CT 06510, USA; Department of Neurology and Cellular and Molecular Physiology, Yale University, New Haven, CT 06510, USA; Department of Neurology, University of Washington, Seattle, WA 98105, USA.
| |
Collapse
|
17
|
Holley SM, Galvan L, Kamdjou T, Dong A, Levine MS, Cepeda C. Major Contribution of Somatostatin-Expressing Interneurons and Cannabinoid Receptors to Increased GABA Synaptic Activity in the Striatum of Huntington's Disease Mice. Front Synaptic Neurosci 2019; 11:14. [PMID: 31139071 PMCID: PMC6527892 DOI: 10.3389/fnsyn.2019.00014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 04/23/2019] [Indexed: 01/01/2023] Open
Abstract
Huntington’s disease (HD) is a heritable neurological disorder that affects cognitive and motor performance in patients carrying the mutated huntingtin (HTT) gene. In mouse models of HD, previous reports showed a significant increase in spontaneous GABAA receptor-mediated synaptic activity in striatal spiny projection neurons (SPNs). In this study, using optogenetics and slice electrophysiology, we examined the contribution of γ-aminobutyric acid (GABA)-ergic parvalbumin (PV)- and somatostatin (SOM)-expressing interneurons to the increase in GABA neurotransmission using the Q175 (heterozygote) mouse model of HD. Patch clamp recordings in voltage-clamp mode were performed on SPNs from brain slices of presymptomatic (2 months) and symptomatic (8 and 12 months) Q175 mice and wildtype (WT) littermates. While inhibitory postsynaptic currents (IPSCs) evoked in SPNs following optical activation of PV- and SOM-expressing interneurons differed in amplitude, no genotype-dependent differences were observed at all ages from both interneuron types; however, responses evoked by either type were found to have faster kinetics in symptomatic mice. Since SOM-expressing interneurons are constitutively active in striatal brain slices, we then examined the effects of acutely silencing these neurons in symptomatic mice with enhanced Natronomonas pharaonis halorhodopsin (eNpHR). Optically silencing SOM-expressing interneurons resulted in a greater decrease in the frequency of spontaneous IPSCs (sIPSCs) in a subset of SPNs from Q175 mice compared to WTs, suggesting that SOM-expressing interneurons are the main contributors to the overall increased GABA synaptic activity in HD SPNs. Additionally, the effects of activating GABAB and cannabinoid (CB1) receptors were investigated to determine whether these receptors were involved in modulating interneuron-specific GABA synaptic transmission and if this modulation differed in HD mice. When selectively activating PV- and SOM-expressing interneurons in the presence of the CB1 receptor agonist WIN-55,212, the magnitudes of the evoked IPSCs in SPNs decreased for both interneuron types although this change was less prominent in symptomatic Q175 SPNs during SOM-expressing interneuron activation. Overall, these findings show that dysfunction of SOM-expressing interneurons contributes to the increased GABA synaptic activity found in HD mouse models and that dysregulation of the endocannabinoid system may contribute to this effect.
Collapse
Affiliation(s)
- Sandra M Holley
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Laurie Galvan
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Talia Kamdjou
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Ashley Dong
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
18
|
Striatal Low-Threshold Spiking Interneurons Regulate Goal-Directed Learning. Neuron 2019; 103:92-101.e6. [PMID: 31097361 DOI: 10.1016/j.neuron.2019.04.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/04/2019] [Accepted: 04/09/2019] [Indexed: 01/06/2023]
Abstract
The dorsomedial striatum (DMS) is critically involved in motor control and reward processing, but the specific neural circuit mediators are poorly understood. Recent evidence highlights the extensive connectivity of low-threshold spiking interneurons (LTSIs) within local striatal circuitry; however, the in vivo function of LTSIs remains largely unexplored. We employed fiber photometry to assess LTSI calcium activity in a range of DMS-mediated behaviors, uncovering specific reward-related activity that is down-modulated during goal-directed learning. Using two mechanistically distinct manipulations, we demonstrated that this down-modulation of LTSI activity is critical for acquisition of novel contingencies, but not for their modification. In contrast, continued LTSI activation slowed instrumental learning. Similar manipulations of fast-spiking interneurons did not reproduce these effects, implying a specific function of LTSIs. Finally, we revealed a role for the γ-aminobutyric acid (GABA)ergic functions of LTSIs in learning. Together, our data provide new insights into this striatal interneuron subclass as important gatekeepers of goal-directed learning.
Collapse
|
19
|
Plotkin JL, Goldberg JA. Thinking Outside the Box (and Arrow): Current Themes in Striatal Dysfunction in Movement Disorders. Neuroscientist 2018; 25:359-379. [PMID: 30379121 PMCID: PMC6529282 DOI: 10.1177/1073858418807887] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The basal ganglia are an intricately connected assembly of subcortical nuclei, forming the core of an adaptive network connecting cortical and thalamic circuits. For nearly three decades, researchers and medical practitioners have conceptualized how the basal ganglia circuit works, and how its pathology underlies motor disorders such as Parkinson's and Huntington's diseases, using what is often referred to as the "box-and-arrow model": a circuit diagram showing the broad strokes of basal ganglia connectivity and the pathological increases and decreases in the weights of specific connections that occur in disease. While this model still has great utility and has led to groundbreaking strategies to treat motor disorders, our evolving knowledge of basal ganglia function has made it clear that this classic model has several shortcomings that severely limit its predictive and descriptive abilities. In this review, we will focus on the striatum, the main input nucleus of the basal ganglia. We describe recent advances in our understanding of the rich microcircuitry and plastic capabilities of the striatum, factors not captured by the original box-and-arrow model, and provide examples of how such advances inform our current understanding of the circuit pathologies underlying motor disorders.
Collapse
Affiliation(s)
- Joshua L Plotkin
- Department of Neurobiology and Behavior, Stony Brook University School of Medicine, Stony Brook, NY, USA
| | - Joshua A Goldberg
- Department of Medical Neurobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|
20
|
Aguilera-Portillo G, Rangel-López E, Villeda-Hernández J, Chavarría A, Castellanos P, Elmazoglu Z, Karasu Ç, Túnez I, Pedraza G, Königsberg M, Santamaría A. The Pharmacological Inhibition of Fatty Acid Amide Hydrolase Prevents Excitotoxic Damage in the Rat Striatum: Possible Involvement of CB1 Receptors Regulation. Mol Neurobiol 2018; 56:844-856. [DOI: 10.1007/s12035-018-1129-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/14/2018] [Indexed: 02/06/2023]
|
21
|
Striatal Direct and Indirect Pathway Output Structures Are Differentially Altered in Mouse Models of Huntington's Disease. J Neurosci 2018; 38:4678-4694. [PMID: 29691329 DOI: 10.1523/jneurosci.0434-18.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/02/2018] [Accepted: 04/18/2018] [Indexed: 11/21/2022] Open
Abstract
The present study examined synaptic communication between direct and indirect output pathway striatal medium-sized spiny neurons (MSNs) and their target structures, the substantia nigra pars reticulata (SNr) and the external globus pallidus (GPe) in two mouse models of Huntington's disease (HD). Cre recombination, optogenetics, and whole-cell patch-clamp recordings were used to determine alterations in intrinsic and synaptic properties of SNr and GPe neurons from both male and female symptomatic R6/2 (>60 d) and presymptomatic (2 months) or symptomatic (10-12 months) YAC128 mice. Cell membrane capacitance was decreased, whereas input resistance was increased in SNr neurons from R6/2, but not YAC128 mice. The amplitude of GABAergic responses evoked by optogenetic stimulation of direct pathway terminals was reduced in SNr neurons of symptomatic mice of both models. A decrease in spontaneous GABA synaptic activity, in particular large-amplitude events, in SNr neurons also was observed. Passive membrane properties of GPe neurons were not different between R6/2 or YAC128 mice and their control littermates. Similarly, the amplitude of GABA responses evoked by activation of indirect pathway MSN terminals and the frequency of spontaneous GABA synaptic activity were similar in HD and control animals. In contrast, the decay time of the evoked GABA response was significantly longer in cells from HD mice. Interestingly, activation of indirect pathway MSNs within the striatum evoked larger-amplitude responses in direct pathway MSNs. Together, these results demonstrate differential alterations in responses evoked by direct and indirect pathway terminals in SNr and GPe leading to striatal output imbalance and motor dysfunction.SIGNIFICANCE STATEMENT Previous work on Huntington's disease (HD) focused on striatal medium-sized spiny neurons (MSNs) almost exclusively. Little is known about the effects that alterations in the striatum have on output structures of the direct and indirect pathways, the substantia nigra pars reticulata (SNr) and the external segment of the globus pallidus (GPe), respectively. We combined electrophysiological and optogenetic methods to examine responses evoked by selective activation of terminals of direct and indirect pathway MSNs in SNr and GPe neurons in two mouse models of HD. We show a differential disruption of synaptic communication between the direct and indirect output pathways of the striatum with their target regions leading to an imbalance of striatal output, which will contribute to motor dysfunction.
Collapse
|
22
|
Reiner A, Deng Y. Disrupted striatal neuron inputs and outputs in Huntington's disease. CNS Neurosci Ther 2018; 24:250-280. [PMID: 29582587 PMCID: PMC5875736 DOI: 10.1111/cns.12844] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 12/22/2022] Open
Abstract
Huntington's disease (HD) is a hereditary progressive neurodegenerative disorder caused by a CAG repeat expansion in the gene coding for the protein huntingtin, resulting in a pathogenic expansion of the polyglutamine tract in the N-terminus of this protein. The HD pathology resulting from the mutation is most prominent in the striatal part of the basal ganglia, and progressive differential dysfunction and loss of striatal projection neurons and interneurons account for the progression of motor deficits seen in this disease. The present review summarizes current understanding regarding the progression in striatal neuron dysfunction and loss, based on studies both in human HD victims and in genetic mouse models of HD. We review evidence on early loss of inputs to striatum from cortex and thalamus, which may be the basis of the mild premanifest bradykinesia in HD, as well as on the subsequent loss of indirect pathway striatal projection neurons and their outputs to the external pallidal segment, which appears to be the basis of the chorea seen in early symptomatic HD. Later loss of direct pathway striatal projection neurons and their output to the internal pallidal segment account for the severe akinesia seen late in HD. Loss of parvalbuminergic striatal interneurons may contribute to the late dystonia and rigidity.
Collapse
Affiliation(s)
- Anton Reiner
- Department of Anatomy & NeurobiologyThe University of Tennessee Health Science CenterMemphisTNUSA
- Department of OphthalmologyThe University of Tennessee Health Science CenterMemphisTNUSA
| | - Yun‐Ping Deng
- Department of Anatomy & NeurobiologyThe University of Tennessee Health Science CenterMemphisTNUSA
| |
Collapse
|
23
|
Assous M, Tepper JM. Excitatory extrinsic afferents to striatal interneurons and interactions with striatal microcircuitry. Eur J Neurosci 2018; 49:593-603. [PMID: 29480942 DOI: 10.1111/ejn.13881] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/20/2018] [Accepted: 02/20/2018] [Indexed: 01/24/2023]
Abstract
The striatum constitutes the main input structure of the basal ganglia and receives two major excitatory glutamatergic inputs, from the cortex and the thalamus. Excitatory cortico- and thalamostriatal connections innervate the principal neurons of the striatum, the spiny projection neurons (SPNs), which constitute the main cellular input as well as the only output of the striatum. In addition, corticostriatal and thalamostriatal inputs also innervate striatal interneurons. Some of these inputs have been very well studied, for example the thalamic innervation of cholinergic interneurons and the cortical innervation of striatal fast-spiking interneurons, but inputs to most other GABAergic interneurons remain largely unstudied, due in part to the relatively recent identification and characterization of many of these interneurons. In this review, we will discuss and reconcile some older as well as more recent data on the extrinsic excitatory inputs to striatal interneurons. We propose that the traditional feed-forward inhibitory model of the cortical input to the fast-spiking interneuron then inhibiting the SPN, often assumed to be the prototype of the main functional organization of striatal interneurons, is incomplete. We provide evidence that the extrinsic innervation of striatal interneurons is not uniform but shows great cell-type specificity. In addition, we will review data showing that striatal interneurons are themselves interconnected in a highly cell-type-specific manner. These data suggest that the impact of the extrinsic inputs on striatal activity critically depends on synaptic interactions within interneuronal circuitry.
Collapse
Affiliation(s)
- Maxime Assous
- Center for Molecular and Behavioral Neuroscience, Rutgers, the State University of New Jersey, 197 University Avenue, Newark, NJ, 07102, USA
| | - James M Tepper
- Center for Molecular and Behavioral Neuroscience, Rutgers, the State University of New Jersey, 197 University Avenue, Newark, NJ, 07102, USA
| |
Collapse
|
24
|
Holley SM, Kamdjou T, Reidling JC, Fury B, Coleal-Bergum D, Bauer G, Thompson LM, Levine MS, Cepeda C. Therapeutic effects of stem cells in rodent models of Huntington's disease: Review and electrophysiological findings. CNS Neurosci Ther 2018; 24:329-342. [PMID: 29512295 DOI: 10.1111/cns.12839] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 02/13/2018] [Accepted: 02/13/2018] [Indexed: 01/01/2023] Open
Abstract
The principal symptoms of Huntington's disease (HD), chorea, cognitive deficits, and psychiatric symptoms are associated with the massive loss of striatal and cortical projection neurons. As current drug therapies only partially alleviate symptoms, finding alternative treatments has become peremptory. Cell replacement using stem cells is a rapidly expanding field that offers such an alternative. In this review, we examine recent studies that use mesenchymal cells, as well as pluripotent, cell-derived products in animal models of HD. Additionally, we provide further electrophysiological characterization of a human neural stem cell line, ESI-017, which has already demonstrated disease-modifying properties in two mouse models of HD. Overall, the field of regenerative medicine represents a viable and promising avenue for the treatment of neurodegenerative disorders including HD.
Collapse
Affiliation(s)
- Sandra M Holley
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA
| | - Talia Kamdjou
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA
| | - Jack C Reidling
- Institute for Memory Impairment and Neurological Disorders, University of California, Irvine, CA, USA
| | - Brian Fury
- Institute for Regenerative Cures, University of California, Davis, Sacramento, CA, USA
| | - Dane Coleal-Bergum
- Institute for Regenerative Cures, University of California, Davis, Sacramento, CA, USA
| | - Gerhard Bauer
- Institute for Regenerative Cures, University of California, Davis, Sacramento, CA, USA
| | - Leslie M Thompson
- Institute for Memory Impairment and Neurological Disorders, University of California, Irvine, CA, USA.,Department of Neurobiology & Behavior and Department of Psychiatry & Human Behavior, University of California, Irvine, CA, USA.,Sue and Bill Gross Stem Cell Center, University of California, Irvine, CA, USA
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA
| |
Collapse
|
25
|
Garret M, Du Z, Chazalon M, Cho YH, Baufreton J. Alteration of GABAergic neurotransmission in Huntington's disease. CNS Neurosci Ther 2018; 24:292-300. [PMID: 29464851 DOI: 10.1111/cns.12826] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/23/2018] [Accepted: 01/26/2018] [Indexed: 12/16/2022] Open
Abstract
Hereditary Huntington's disease (HD) is characterized by cell dysfunction and death in the brain, leading to progressive cognitive, psychiatric, and motor impairments. Despite molecular and cellular descriptions of the effects of the HD mutation, no effective pharmacological treatment is yet available. In addition to well-established alterations of glutamatergic and dopaminergic neurotransmitter systems, it is becoming clear that the GABAergic systems are also impaired in HD. GABA is the major inhibitory neurotransmitter in the brain, and GABAergic neurotransmission has been postulated to be modified in many neurological and psychiatric diseases. In addition, GABAergic neurotransmission is the target of many drugs that are in wide clinical use. Here, we summarize data demonstrating the occurrence of alterations of GABAergic markers in the brain of HD carriers as well as in rodent models of the disease. In particular, we pinpoint HD-related changes in the expression of GABAA receptors (GABAA Rs). On the basis that a novel GABA pharmacology of GABAA Rs established with more selective drugs is emerging, we argue that clinical treatments acting specifically on GABAergic neurotransmission may be an appropriate strategy for improving symptoms linked to the HD mutation.
Collapse
Affiliation(s)
- Maurice Garret
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Zhuowei Du
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Marine Chazalon
- Institut des Maladies Neurodégénératives, Université de Bordeaux, UMR 5293, Bordeaux, France.,Institut des Maladies Neurodégénératives, CNRS, UMR 5293, Bordeaux, France
| | - Yoon H Cho
- Université de Bordeaux, INCIA, UMR 5287, Bordeaux, France.,CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Jérôme Baufreton
- Institut des Maladies Neurodégénératives, Université de Bordeaux, UMR 5293, Bordeaux, France.,Institut des Maladies Neurodégénératives, CNRS, UMR 5293, Bordeaux, France
| |
Collapse
|
26
|
Abstract
Electrophysiological and cell imaging techniques are powerful tools for understanding alterations in neuronal activity in Huntington's disease (HD), a fatal neurological disorder caused by an expansion of CAG repeats in the HTT gene. Changes in neuronal activity often precede the behavioral manifestations of HD, therefore, understanding the electrophysiology of HD is critical for identifying potential prodromal markers and therapeutic targets. This chapter outlines the basic methodology behind four major electrophysiological and imaging techniques used in HD mouse models: patch clamp recordings, optogenetics, in vivo electrophysiology, and Ca2+ imaging, as well as some of the advancements in HD research using each of these techniques.
Collapse
|
27
|
D’Souza GX, Waldvogel HJ. Targeting the Cholinergic System to Develop a Novel Therapy for Huntington's Disease. J Huntingtons Dis 2017; 5:333-342. [PMID: 27983560 PMCID: PMC5181681 DOI: 10.3233/jhd-160200] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this review, we outline the role of the cholinergic system in Huntington’s disease, and briefly describe the dysfunction of cholinergic transmission, cholinergic neurons, cholinergic receptors and cholinergic survival factors observed in post-mortem human brains and animal models of Huntington’s disease. We postulate how the dysfunctional cholinergic system can be targeted to develop novel therapies for Huntington’s disease, and discuss the beneficial effects of cholinergic therapies in pre-clinical and clinical studies.
Collapse
Affiliation(s)
| | - Henry J. Waldvogel
- Correspondence to: Associate Professor Henry J. Waldvogel, Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand. Tel.: +64 9 923 6051; E-mail:
| |
Collapse
|
28
|
Nakajima A, Shimo Y, Uka T, Hattori N. Subthalamic nucleus and globus pallidus interna influence firing of tonically active neurons in the primate striatum through different mechanisms. Eur J Neurosci 2017; 46:2662-2673. [PMID: 28949036 PMCID: PMC5765455 DOI: 10.1111/ejn.13726] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 11/30/2022]
Abstract
Both the subthalamic nucleus (STN) and the globus pallidus pars interna (GPi) are major targets for neuromodulation therapy for movement disorders. An example of such a therapy is deep brain stimulation (DBS). The striatum is the primary target for pharmacological treatment of these disorders. To further our understanding of both the functional relationships among motor nuclei and the mechanisms of therapies for movement disorders, it is important to clarify how changing the neuronal activity of one target, either by medication or by artificial electrical stimulation, affects the other connected nuclei. To investigate this point, we recorded single-unit activity from tonically active neurons (TANs), which are putative cholinergic interneurons in the striatum, of healthy monkeys (Macaca fuscata) during electrical stimulation of the STN or GPi. Both STN stimulation and GPi stimulation reduced the TAN spike rate. Local infusion of a D2 receptor antagonist in the striatum blocked the reduction in spike rate induced by STN stimulation but not that induced by GPi stimulation. Further, STN stimulation induced phasic dopamine release in the striatum as revealed by in vivo fast-scan cyclic voltammetry. These results suggest the presence of multiple, strong functional relationships among the STN, GPi, and striatum that have different pathways and imply distinct therapeutic mechanisms for STN- and GPi-DBS.
Collapse
Affiliation(s)
- Asuka Nakajima
- Department of Neurology, School of Medicine, Juntendo University, Tokyo, Japan
| | - Yasushi Shimo
- Department of Neurology, School of Medicine, Juntendo University, Tokyo, Japan.,Department of Research and Therapeutics for Movement Disorders, School of Medicine, Juntendo University, Tokyo, Japan
| | - Takanori Uka
- Department of Physiology, School of Medicine, Juntendo University, Tokyo, Japan
| | - Nobutaka Hattori
- Department of Neurology, School of Medicine, Juntendo University, Tokyo, Japan
| |
Collapse
|
29
|
Hsu YT, Chang YG, Chang CP, Siew JJ, Chen HM, Tsai CH, Chern Y. Altered behavioral responses to gamma-aminobutyric acid pharmacological agents in a mouse model of Huntington's disease. Mov Disord 2017; 32:1600-1609. [PMID: 28782830 DOI: 10.1002/mds.27107] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 06/21/2017] [Accepted: 06/23/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Disruptions in gamma-aminobutyric (GABA) acid signaling are believed to be involved in Huntington's disease pathogenesis, but the regulation of GABAergic signaling remains elusive. Here we evaluated GABAergic signaling by examining the function of GABAergic drugs in Huntington's disease and the expression of GABAergic molecules using mouse models and human brain tissues from Huntington's disease. METHODS We treated wild-type and R6/2 mice (a transgenic Huntington's disease mouse model) acutely with vehicle, diazepam, or gaboxadol (drugs that selectively target synaptic or extrasynaptic GABAA receptors) and monitored their locomotor activity. The expression levels of GABAA receptors and a major neuron-specific chloride extruder (potassium-chloride cotransporter-2) were analyzed by real-time quantitative polymerase chain reaction, Western blot, and immunocytochemistry. RESULTS The R6/2 mice were less sensitive to the sedative effects of both drugs, suggesting reduced function of GABAA receptors. Consistently, the expression levels of α1/α2 and δ subunits were lower in the cortex and striatum of R6/2 mice. Similar results were also found in 2 other mouse models of Huntington's disease and in Huntington's disease patients. Moreover, the interaction and expression levels of potassium-chloride cotransporter-2 and its activator (brain-type creatine kinase) were decreased in Huntington's disease neurons. These findings collectively suggest impaired chloride homeostasis, which further dampens GABAA receptor-mediated inhibitory signaling in Huntington's disease brains. CONCLUSIONS The dysregulated GABAergic responses and altered expression levels of GABAA receptors and potassium-chloride cotransporter-2 in Huntington's disease mice appear to be authentic and may contribute to the clinical manifestations of Huntington's disease patients. © 2017 International Parkinson and Movement Disorder Society.
Collapse
Affiliation(s)
- Yi-Ting Hsu
- Ph.D. Program for Translational Medicine, China Medical University and Academia Sinica, Taiwan.,Department of Neurology, China Medical University Hospital, Taichung, Taiwan
| | - Ya-Gin Chang
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan.,Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
| | - Ching-Pang Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Jian-Jing Siew
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hui-Mei Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chon-Haw Tsai
- Ph.D. Program for Translational Medicine, China Medical University and Academia Sinica, Taiwan.,Department of Neurology, China Medical University Hospital, Taichung, Taiwan
| | - Yijuang Chern
- Ph.D. Program for Translational Medicine, China Medical University and Academia Sinica, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| |
Collapse
|
30
|
Pepeu G, Grazia Giovannini M. The fate of the brain cholinergic neurons in neurodegenerative diseases. Brain Res 2017; 1670:173-184. [PMID: 28652219 DOI: 10.1016/j.brainres.2017.06.023] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 01/03/2023]
Abstract
The aims of this review are: 1) to describe which cholinergic neurons are affected in brain neurodegenerative diseases leading to dementia; 2) to discuss the possible causes of the degeneration of the cholinergic neurons, 3) to summarize the functional consequences of the cholinergic deficit. The brain cholinergic system is basically constituted by three populations of phenotypically similar neurons forming a series of basal forebrain nuclei, the midpontine nuclei and a large population of striatal interneurons. In Alzheimer's disease there is an extensive loss of forebrain cholinergic neurons accompanied by a reduction of the cholinergic fiber network of the cortical mantel and hippocampus. The midpontine cholinergic nuclei are spared. The same situation occurs in the corticobasal syndrome and dementia following alcohol abuse and traumatic brain injury. Conversely, in Parkinson's disease, the midpontine nuclei degenerate, together with the dopaminergic nuclei, reducing the cholinergic input to thalamus and forebrain whereas the forebrain cholinergic neurons are spared. In Parkinson's disease with dementia, Lewis Body Dementia and Parkinsonian syndromes both groups of forebrain and midpontine cholinergic nuclei degenerate. In Huntington's disease a dysfunction of the striatal cholinergic interneurons without cell loss takes place. The formation and accumulation of misfolded proteins such as β-amyloid oligomers and plaques, tau protein tangles and α-synuclein clumps, and aggregated mutated huntingtin play a crucial role in the neuronal degeneration by direct cellular toxicity of the misfolded proteins and through the toxic compounds resulting from an extensive inflammatory reaction. Evidences indicate that β-amyloid disrupts NGF metabolism causing the degeneration of the cholinergic neurons which depend on NGF for their survival, namely the forebrain cholinergic neurons, sparing the midpontine and striatal neurons which express no specific NGF receptors. It is feasible that the latter cholinergic neurons may be damaged by direct toxicity of tau, α-synuclein and inflammations products through mechanisms not fully understood. Attention and learning and memory impairment are the functional consequences of the forebrain cholinergic neuron dysfunction, whereas the loss of midpontine cholinergic neurons results primarily in motor and sleep disturbances.
Collapse
Affiliation(s)
- Giancarlo Pepeu
- Department of Health Sciences, University of Florence, Viale G. Pieraccini 6, 50139 Florence, Italy.
| | - Maria Grazia Giovannini
- Department of Health Sciences, University of Florence, Viale G. Pieraccini 6, 50139 Florence, Italy.
| |
Collapse
|
31
|
Du Z, Tertrais M, Courtand G, Leste-Lasserre T, Cardoit L, Masmejean F, Halgand C, Cho YH, Garret M. Differential Alteration in Expression of Striatal GABA AR Subunits in Mouse Models of Huntington's Disease. Front Mol Neurosci 2017; 10:198. [PMID: 28676743 PMCID: PMC5476702 DOI: 10.3389/fnmol.2017.00198] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 06/06/2017] [Indexed: 12/20/2022] Open
Abstract
Huntington’s disease (HD) is a neurodegenerative disorder characterized by progressive motor symptoms that are preceded by cognitive deficits and is considered as a disorder that primarily affects forebrain striatal neurons. To gain a better understanding of the molecular and cellular mechanisms associated with disease progression, we analyzed the expression of proteins involved in GABAergic neurotransmission in the striatum of the R6/1 transgenic mouse model. Western blot, quantitative PCR and immunohistochemical analyses were conducted on male R6/1 mice and age-matched wild type littermates. Analyses were performed on 2 and 6 month-old animals, respectively, before and after the onset of motor symptoms. Expression of GAD 67, GAD 65, NL2, or gephyrin proteins, involved in GABA synthesis or synapse formation did not display major changes. In contrast, expression of α1, α3 and α5 GABAAR subunits was increased while the expression of δ was decreased, suggesting a change in tonic- and phasic inhibitory transmission. Western blot analysis of the striatum from 8 month-old Hdh Q111, a knock-in mouse model of HD with mild deficits, confirmed the α1 subunit increased expression. From immunohistochemical analyses, we also found that α1 subunit expression is increased in medium-sized spiny projection neurons (MSN) and decreased in parvalbumin (PV)-expressing interneurons at 2 and 6 months in R6/1 mice. Moreover, α2 subunit labeling on the PV and MSN cell membranes was increased at 2 months and decreased at 6 months. Alteration of gene expression in the striatum and modification of GABAA receptor subtypes in both interneurons and projection neurons suggested that HD mutation has a profound effect on synaptic plasticity at an early stage, before the onset of motor symptoms. These results also indicate that cognitive and other behavioral deficits may be associated with changes in GABAergic neurotransmission that consequently could be a relevant target for early therapeutic treatment.
Collapse
Affiliation(s)
- Zhuowei Du
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Margot Tertrais
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Gilles Courtand
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Thierry Leste-Lasserre
- Institut National de la Santé et de la Recherche Médicale, Neurocentre Magendie, U862, Physiopathologie de la Plasticité NeuronaleBordeaux, France.,Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U862, University of BordeauxBordeaux, France
| | - Laura Cardoit
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Frédérique Masmejean
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Christophe Halgand
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Yoon H Cho
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| | - Maurice Garret
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, University of BordeauxBordeaux, France.,Centre National de la Recherche Scientifique, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287Bordeaux, France
| |
Collapse
|
32
|
Tanimura A, Lim SAO, Aceves Buendia JDJ, Goldberg JA, Surmeier DJ. Cholinergic Interneurons Amplify Corticostriatal Synaptic Responses in the Q175 Model of Huntington's Disease. Front Syst Neurosci 2016; 10:102. [PMID: 28018188 PMCID: PMC5159611 DOI: 10.3389/fnsys.2016.00102] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/02/2016] [Indexed: 01/18/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder characterized by deficits in movement control that are widely viewed as stemming from pathophysiological changes in the striatum. Giant, aspiny cholinergic interneurons (ChIs) are key elements in the striatal circuitry controlling movement, but whether their physiological properties are intact in the HD brain is unclear. To address this issue, the synaptic properties of ChIs were examined using optogenetic approaches in the Q175 mouse model of HD. In ex vivo brain slices, synaptic facilitation at thalamostriatal synapses onto ChIs was reduced in Q175 mice. The alteration in thalamostriatal transmission was paralleled by an increased response to optogenetic stimulation of cortical axons, enabling these inputs to more readily induce burst-pause patterns of activity in ChIs. This adaptation was dependent upon amplification of cortically evoked responses by a post-synaptic upregulation of voltage-dependent Na+ channels. This upregulation also led to an increased ability of somatic spikes to invade ChI dendrites. However, there was not an alteration in the basal pacemaking rate of ChIs, possibly due to increased availability of Kv4 channels. Thus, there is a functional "re-wiring" of the striatal networks in Q175 mice, which results in greater cortical control of phasic ChI activity, which is widely thought to shape the impact of salient stimuli on striatal action selection.
Collapse
Affiliation(s)
- Asami Tanimura
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Sean Austin O Lim
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Jose de Jesus Aceves Buendia
- Department of Medical Neurobiology, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem Jerusalem, Israel
| | - Joshua A Goldberg
- Department of Medical Neurobiology, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem Jerusalem, Israel
| | - D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| |
Collapse
|
33
|
Simmons DA, Belichenko NP, Ford EC, Semaan S, Monbureau M, Aiyaswamy S, Holman CM, Condon C, Shamloo M, Massa SM, Longo FM. A small molecule p75NTR ligand normalizes signalling and reduces Huntington's disease phenotypes in R6/2 and BACHD mice. Hum Mol Genet 2016; 25:4920-4938. [PMID: 28171570 PMCID: PMC5418739 DOI: 10.1093/hmg/ddw316] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 08/18/2016] [Accepted: 09/12/2016] [Indexed: 01/03/2023] Open
Abstract
Decreases in the ratio of neurotrophic versus neurodegenerative signalling play a critical role in Huntington’s disease (HD) pathogenesis and recent evidence suggests that the p75 neurotrophin receptor (NTR) contributes significantly to disease progression. p75NTR signalling intermediates substantially overlap with those promoting neuronal survival and synapse integrity and with those affected by the mutant huntingtin (muHtt) protein. MuHtt increases p75NTR-associated deleterious signalling and decreases survival signalling suggesting that p75NTR could be a valuable therapeutic target. This hypothesis was investigated by examining the effects of an orally bioavailable, small molecule p75NTR ligand, LM11A-31, on HD-related neuropathology in HD mouse models (R6/2, BACHD). LM11A-31 restored striatal AKT and other pro-survival signalling while inhibiting c-Jun kinase (JNK) and other degenerative signalling. Normalizing p75NTR signalling with LM11A-31 was accompanied by reduced Htt aggregates and striatal cholinergic interneuron degeneration as well as extended survival in R6/2 mice. The p75NTR ligand also decreased inflammation, increased striatal and hippocampal dendritic spine density, and improved motor performance and cognition in R6/2 and BACHD mice. These results support small molecule modulation of p75NTR as an effective HD therapeutic strategy. LM11A-31 has successfully completed Phase I safety and pharmacokinetic clinical trials and is therefore a viable candidate for clinical studies in HD.
Collapse
Affiliation(s)
- Danielle A. Simmons
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine
| | - Nadia P. Belichenko
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine
| | - Ellen C. Ford
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine
| | - Sarah Semaan
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine
| | - Marie Monbureau
- Behavioral and Functional Neuroscience Laboratory, Institute for Neuro-Innovation and Translational Neurosciences
| | - Sruti Aiyaswamy
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine
| | - Cameron M. Holman
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine
| | - Christina Condon
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine
| | - Mehrdad Shamloo
- Behavioral and Functional Neuroscience Laboratory, Institute for Neuro-Innovation and Translational Neurosciences
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Stephen M. Massa
- Department of Neurology and Laboratory for Computational Neurochemistry and Drug Discovery, Department of Veterans Affairs Medical Center and Department of Neurology, University of California–San Francisco, San Francisco, CA, USA
| | - Frank M. Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine
| |
Collapse
|
34
|
Akopian G, Barry J, Cepeda C, Levine MS. Altered membrane properties and firing patterns of external globus pallidus neurons in the R6/2 mouse model of Huntington's disease. J Neurosci Res 2016; 94:1400-1410. [PMID: 27618125 DOI: 10.1002/jnr.23889] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 12/24/2022]
Abstract
In mouse models of Huntington's disease (HD), striatal neuron properties are significantly altered. These alterations predict changes in striatal output regions. However, little is known about alterations in those regions. The present study examines changes in passive and active membrane properties of neurons in the external globus pallidus (GPe), the first relay station of the indirect pathway, in the R6/2 mouse model of juvenile HD at presymptomatic (1 month) and symptomatic (2 month) stages. In GPe, two principal types of neurons can be distinguished based on firing properties and the presence (type A) or absence (type B) of Ih currents. In symptomatic animals (2 month), cell membrane capacitance and input resistance of type A neurons were increased compared with controls. In addition, action potential afterhyperpolarization amplitude was reduced. Although the spontaneous firing rate of GPe neurons was not different between control and R6/2 mice, the number of spikes evoked by depolarizing current pulses was significantly reduced in symptomatic R6/2 animals. In addition, these changes were accompanied by altered firing patterns evidenced by increased interspike interval variation and increased number of bursts. Blockade of GABAA receptors facilitated bursting activity in R6/2 mice but not in control littermates. Thus, alterations in firing patterns could be caused by changes in intrinsic membrane conductances and modulated by synaptic inputs. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Garnik Akopian
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, California
| | - Joshua Barry
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, California
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, California
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, California.
| |
Collapse
|
35
|
Deng YP, Reiner A. Cholinergic interneurons in the Q140 knockin mouse model of Huntington's disease: Reductions in dendritic branching and thalamostriatal input. J Comp Neurol 2016; 524:3518-3529. [PMID: 27219491 DOI: 10.1002/cne.24013] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/29/2016] [Accepted: 04/06/2016] [Indexed: 12/19/2022]
Abstract
We have previously found that thalamostriatal axodendritic terminals are reduced as early as 1 month of age in heterozygous Q140 HD mice (Deng et al. [] Neurobiol Dis 60:89-107). Because cholinergic interneurons are a major target of thalamic axodendritic terminals, we examined the VGLUT2-immunolabeled thalamic input to striatal cholinergic interneurons in heterozygous Q140 males at 1 and 4 months of age, using choline acetyltransferase (ChAT) immunolabeling to identify cholinergic interneurons. Although blinded neuron counts showed that ChAT+ perikarya were in normal abundance in Q140 mice, size measurements indicated that they were significantly smaller. Sholl analysis further revealed the dendrites of Q140 ChAT+ interneurons were significantly fewer and shorter. Consistent with the light microscopic data, ultrastructural analysis showed that the number of ChAT+ dendritic profiles per unit area of striatum was significantly decreased in Q140 striata, as was the abundance of VGLUT2+ axodendritic terminals making synaptic contact with ChAT+ dendrites per unit area of striatum. The density of thalamic terminals along individual cholinergic dendrites was, however, largely unaltered, indicating that the reduction in the areal striatal density of axodendritic thalamic terminals on cholinergic neurons was due to their dendritic territory loss. These results show that the abundance of thalamic input to individual striatal cholinergic interneurons is reduced early in the life span of Q140 mice, raising the possibility that this may occur in human HD as well. Because cholinergic interneurons differentially affect striatal direct vs. indirect pathway spiny projection neurons, their reduced thalamic excitatory drive may contribute to early abnormalities in movement in HD. J. Comp. Neurol. 524:3518-3529, 2016. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Yun-Ping Deng
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, 38163
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, 38163.
| |
Collapse
|
36
|
Sizemore RJ, Seeger-Armbruster S, Hughes SM, Parr-Brownlie LC. Viral vector-based tools advance knowledge of basal ganglia anatomy and physiology. J Neurophysiol 2016; 115:2124-46. [PMID: 26888111 PMCID: PMC4869490 DOI: 10.1152/jn.01131.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/16/2016] [Indexed: 01/07/2023] Open
Abstract
Viral vectors were originally developed to deliver genes into host cells for therapeutic potential. However, viral vector use in neuroscience research has increased because they enhance interpretation of the anatomy and physiology of brain circuits compared with conventional tract tracing or electrical stimulation techniques. Viral vectors enable neuronal or glial subpopulations to be labeled or stimulated, which can be spatially restricted to a single target nucleus or pathway. Here we review the use of viral vectors to examine the structure and function of motor and limbic basal ganglia (BG) networks in normal and pathological states. We outline the use of viral vectors, particularly lentivirus and adeno-associated virus, in circuit tracing, optogenetic stimulation, and designer drug stimulation experiments. Key studies that have used viral vectors to trace and image pathways and connectivity at gross or ultrastructural levels are reviewed. We explain how optogenetic stimulation and designer drugs used to modulate a distinct pathway and neuronal subpopulation have enhanced our mechanistic understanding of BG function in health and pathophysiology in disease. Finally, we outline how viral vector technology may be applied to neurological and psychiatric conditions to offer new treatments with enhanced outcomes for patients.
Collapse
Affiliation(s)
- Rachel J Sizemore
- Department of Anatomy, Otago School of Medical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Sonja Seeger-Armbruster
- Department of Physiology, Otago School of Medical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of Otago, Dunedin, New Zealand; and
| | - Stephanie M Hughes
- Department of Biochemistry, Otago School of Medical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Louise C Parr-Brownlie
- Department of Anatomy, Otago School of Medical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of Otago, Dunedin, New Zealand;
| |
Collapse
|
37
|
Rafalovich IV, Melendez AE, Plotkin JL, Tanimura A, Zhai S, Surmeier DJ. Interneuronal Nitric Oxide Signaling Mediates Post-synaptic Long-Term Depression of Striatal Glutamatergic Synapses. Cell Rep 2015; 13:1336-1342. [PMID: 26549446 DOI: 10.1016/j.celrep.2015.10.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 08/10/2015] [Accepted: 10/05/2015] [Indexed: 02/04/2023] Open
Abstract
Experience-driven plasticity of glutamatergic synapses on striatal spiny projection neurons (SPNs) is thought to be essential to goal-directed behavior and habit formation. One major form of striatal plasticity, long-term depression (LTD), has long appeared to be expressed only pre-synaptically. Contrary to this view, nitric oxide (NO) generated by striatal interneurons was found to induce a post-synaptically expressed form of LTD at SPN glutamatergic synapses. This form of LTD was dependent on signaling through guanylyl cyclase and protein kinase G, both of which are abundantly expressed by SPNs. NO-LTD was unaffected by local synaptic activity or antagonism of endocannabinoid (eCb) and dopamine receptors, all of which modulate canonical, pre-synaptic LTD. Moreover, NO signaling disrupted induction of this canonical LTD by inhibiting dendritic Ca(2+) channels regulating eCb synthesis. These results establish an interneuron-dependent, heterosynaptic form of post-synaptic LTD that could act to promote stability of the striatal network during learning.
Collapse
Affiliation(s)
- Igor V Rafalovich
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Alexandria E Melendez
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Joshua L Plotkin
- Department of Neurobiology and Behavior, SUNY at Stony Brook, Stony Brook, NY 11794, USA
| | - Asami Tanimura
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Shenyu Zhai
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
| |
Collapse
|
38
|
Pappas SS, Darr K, Holley SM, Cepeda C, Mabrouk OS, Wong JMT, LeWitt TM, Paudel R, Houlden H, Kennedy RT, Levine MS, Dauer WT. Forebrain deletion of the dystonia protein torsinA causes dystonic-like movements and loss of striatal cholinergic neurons. eLife 2015; 4:e08352. [PMID: 26052670 PMCID: PMC4473728 DOI: 10.7554/elife.08352] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 06/07/2015] [Indexed: 12/12/2022] Open
Abstract
Striatal dysfunction plays an important role in dystonia, but the striatal cell types that contribute to abnormal movements are poorly defined. We demonstrate that conditional deletion of the DYT1 dystonia protein torsinA in embryonic progenitors of forebrain cholinergic and GABAergic neurons causes dystonic-like twisting movements that emerge during juvenile CNS maturation. The onset of these movements coincides with selective degeneration of dorsal striatal large cholinergic interneurons (LCI), and surviving LCI exhibit morphological, electrophysiological, and connectivity abnormalities. Consistent with the importance of this LCI pathology, murine dystonic-like movements are reduced significantly with an antimuscarinic agent used clinically, and we identify cholinergic abnormalities in postmortem striatal tissue from DYT1 dystonia patients. These findings demonstrate that dorsal LCI have a unique requirement for torsinA function during striatal maturation, and link abnormalities of these cells to dystonic-like movements in an overtly symptomatic animal model. DOI:http://dx.doi.org/10.7554/eLife.08352.001 Dystonia is disorder of the nervous system that causes people to suffer from abnormal and involuntary twisting movements. These movements are triggered, in part, by irregularities in a part of the brain called the striatum. The most common view among researchers is that dystonia is caused by abnormal activity in an otherwise structurally normal nervous system. But, recent findings indicate that the degeneration of small populations of nerve cells in the brain may be important. The striatum is made up of several different types of nerve cells, but it is poorly understood which of these are affected in dystonia. One type of dystonia, which most often occurs in children, is caused by a defect in a protein called torsinA. Pappas et al. have now discovered that deleting the gene for torsinA from particular populations of nerve cells in the brains of mice (including a population in the striatum) causes abnormal twisting movements. Like people with dystonia, these mice developed the abnormal movements as juveniles, and the movements were suppressed with ‘anti-cholinergic’ medications. Pappas et al. then analyzed brain tissue from these mice and revealed that the twisting movements began at the same time that a single type of cell in the striatum—called ‘cholinergic interneurons’—degenerated. Postmortem studies of brain tissue from dystonia patients also revealed abnormalities of these neurons. Together these findings challenge the notion that dystonia occurs in a structurally normal nervous system and reveal that cholinergic interneurons in the striatum specifically require torsinA to survive. Following on from this work, the next challenges are to identify what causes the selective loss of cholinergic interneurons, and to investigate how this cell loss affects the activity within the striatum. DOI:http://dx.doi.org/10.7554/eLife.08352.002
Collapse
Affiliation(s)
- Samuel S Pappas
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Katherine Darr
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Sandra M Holley
- Intellectual and Developmental Disabilities Research Center, Brain Research Institute, Semel Institute for Neuroscience, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, Brain Research Institute, Semel Institute for Neuroscience, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Omar S Mabrouk
- Department of Pharmacology, University of Michigan, Ann Arbor, United States
| | - Jenny-Marie T Wong
- Department of Chemistry, University of Michigan, Ann Arbor, United States
| | - Tessa M LeWitt
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Reema Paudel
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, United Kingdom
| | - Henry Houlden
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, United Kingdom
| | - Robert T Kennedy
- Department of Chemistry, University of Michigan, Ann Arbor, United States
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, Brain Research Institute, Semel Institute for Neuroscience, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - William T Dauer
- Department of Neurology, University of Michigan, Ann Arbor, United States
| |
Collapse
|