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Denne T, Winfrey LC, Moore C, Whitner C, D'Silva T, Soumyanath A, Shinto L, Hiller A, Meshul CK. Recovery of motor function is associated with rescue of glutamate biomarkers in the striatum and motor cortex following treatment with Mucuna pruriens in a murine model of Parkinsons disease. Mol Cell Neurosci 2023; 126:103883. [PMID: 37527694 DOI: 10.1016/j.mcn.2023.103883] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/26/2023] [Accepted: 07/24/2023] [Indexed: 08/03/2023] Open
Abstract
There is growing interest in the use of natural products for the treatment of Parkinson's disease (PD). Mucuna pruriens has been used in the treatment of humans with PD. The goal of this study was to determine if daily oral treatment with an extract of Mucuna pruriens, starting after the MPTP-induced loss of nigrostriatal dopamine in male mice, would result in recovery/restoration of motor function, tyrosine hydroxylase (TH) protein expression in the nigrostriatal pathway, or glutamate biomarkers in both the striatum and motor cortex. Following MPTP administration, resulting in an 80 % loss of striatal TH, treatment with Mucuna pruriens failed to rescue either striatal TH or the dopamine transporter back to the control levels, but there was restoration of gait/motor function. There was an MPTP-induced loss of TH-labeled neurons in the substantia nigra pars compacta and in the number of striatal dendritic spines, both of which failed to be recovered following treatment with Mucuna pruriens. This Mucuna pruriens-induced locomotor recovery following MPTP was associated with restoration of two striatal glutamate transporter proteins, GLAST (EAAT1) and EAAC1 (EAAT3), and the vesicular glutamate transporter 2 (Vglut2) within the motor cortex. Post-MPTP treatment with Mucuna pruriens, results in locomotor improvement that is associated with recovery of striatal and motor cortex glutamate transporters but is independent of nigrostriatal TH restoration.
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Affiliation(s)
| | | | - Cindy Moore
- VA Medical Center/Portland, Portland, OR, USA
| | | | | | - Amala Soumyanath
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Lynne Shinto
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Amie Hiller
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA; VA Medical Center/Portland, Portland, OR, USA
| | - Charles K Meshul
- Department of Behavioral Neuroscience and Pathology, Oregon Health & Science University, Portland, OR, USA; VA Medical Center/Portland, Portland, OR, USA.
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2
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Alijanpour S, Miryounesi M, Ghafouri-Fard S. The role of excitatory amino acid transporter 2 (EAAT2) in epilepsy and other neurological disorders. Metab Brain Dis 2023; 38:1-16. [PMID: 36173507 DOI: 10.1007/s11011-022-01091-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/15/2022] [Indexed: 02/03/2023]
Abstract
Glutamate is the major excitatory neurotransmitter in the central nervous system (CNS). Excitatory amino acid transporters (EAATs) have important roles in the uptake of glutamate and termination of glutamatergic transmission. Up to now, five EAAT isoforms (EAAT1-5) have been identified in mammals. The main focus of this review is EAAT2. This protein has an important role in the pathoetiology of epilepsy. De novo dominant mutations, as well as inherited recessive mutation in this gene, have been associated with epilepsy. Moreover, dysregulation of this protein is implicated in a range of neurological diseases, namely amyotrophic lateral sclerosis, alzheimer's disease, parkinson's disease, schizophrenia, epilepsy, and autism. In this review, we summarize the role of EAAT2 in epilepsy and other neurological disorders, then provide an overview of the therapeutic modulation of this protein.
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Affiliation(s)
- Sahar Alijanpour
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Miryounesi
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soudeh Ghafouri-Fard
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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3
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Sobolczyk M, Boczek T. Astrocytic Calcium and cAMP in Neurodegenerative Diseases. Front Cell Neurosci 2022; 16:889939. [PMID: 35663426 PMCID: PMC9161693 DOI: 10.3389/fncel.2022.889939] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/05/2022] [Indexed: 12/18/2022] Open
Abstract
It is commonly accepted that the role of astrocytes exceeds far beyond neuronal scaffold and energy supply. Their unique morphological and functional features have recently brough much attention as it became evident that they play a fundamental role in neurotransmission and interact with synapses. Synaptic transmission is a highly orchestrated process, which triggers local and transient elevations in intracellular Ca2+, a phenomenon with specific temporal and spatial properties. Presynaptic activation of Ca2+-dependent adenylyl cyclases represents an important mechanism of synaptic transmission modulation. This involves activation of the cAMP-PKA pathway to regulate neurotransmitter synthesis, release and storage, and to increase neuroprotection. This aspect is of paramount importance for the preservation of neuronal survival and functionality in several pathological states occurring with progressive neuronal loss. Hence, the aim of this review is to discuss mutual relationships between cAMP and Ca2+ signaling and emphasize those alterations at the Ca2+/cAMP crosstalk that have been identified in neurodegenerative disorders, such as Alzheimer's and Parkinson's disease.
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Prevention of L-Dopa-Induced Dyskinesias by MPEP Blockade of Metabotropic Glutamate Receptor 5 Is Associated with Reduced Inflammation in the Brain of Parkinsonian Monkeys. Cells 2022; 11:cells11040691. [PMID: 35203338 PMCID: PMC8870609 DOI: 10.3390/cells11040691] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 02/01/2023] Open
Abstract
Proinflammatory markers were found in brains of Parkinson’s disease (PD) patients. After years of L-Dopa symptomatic treatment, most PD patients develop dyskinesias. The relationship between inflammation and L-Dopa-induced dyskinesias (LID) is still unclear. We previously reported that MPEP (a metabotropic glutamate receptor 5 antagonist) reduced the development of LID in de novo MPTP-lesioned monkeys. We thus investigated if MPEP reduced the brain inflammatory response in these MPTP-lesioned monkeys and the relationship to LID. The panmacrophage/microglia marker Iba1, the phagocytosis-related receptor CD68, and the astroglial protein GFAP were measured by Western blots. The L-Dopa-treated dyskinetic MPTP monkeys had increased Iba1 content in the putamen, substantia nigra, and globus pallidus, which was prevented by MPEP cotreatment; similar findings were observed for CD68 contents in the putamen and globus pallidus. There was a strong positive correlation between dyskinesia scores and microglial markers in these regions. GFAP contents were elevated in MPTP + L-Dopa-treated monkeys among these brain regions and prevented by MPEP in the putamen and subthalamic nucleus. In conclusion, these results showed increased inflammatory markers in the basal ganglia associated with LID and revealed that MPEP inhibition of glutamate activity reduced LID and levels of inflammatory markers.
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5
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Pajarillo E, Digman A, Nyarko-Danquah I, Son DS, Soliman KFA, Aschner M, Lee E. Astrocytic transcription factor REST upregulates glutamate transporter EAAT2, protecting dopaminergic neurons from manganese-induced excitotoxicity. J Biol Chem 2021; 297:101372. [PMID: 34756885 PMCID: PMC8626589 DOI: 10.1016/j.jbc.2021.101372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 10/18/2021] [Accepted: 10/27/2021] [Indexed: 11/25/2022] Open
Abstract
Chronic exposure to high levels of manganese (Mn) leads to manganism, a neurological disorder with similar symptoms to those inherent to Parkinson's disease. However, the underlying mechanisms of this pathological condition have yet to be established. Since the human excitatory amino acid transporter 2 (EAAT2) (glutamate transporter 1 in rodents) is predominantly expressed in astrocytes and its dysregulation is involved in Mn-induced excitotoxic neuronal injury, characterization of the mechanisms that mediate the Mn-induced impairment in EAAT2 function is crucial for the development of novel therapeutics against Mn neurotoxicity. Repressor element 1-silencing transcription factor (REST) exerts protective effects in many neurodegenerative diseases. But the effects of REST on EAAT2 expression and ensuing neuroprotection are unknown. Given that the EAAT2 promoter contains REST binding sites, the present study investigated the role of REST in EAAT2 expression at the transcriptional level in astrocytes and Mn-induced neurotoxicity in an astrocyte–neuron coculture system. The results reveal that astrocytic REST positively regulates EAAT2 expression with the recruitment of an epigenetic modifier, cAMP response element-binding protein–binding protein/p300, to its consensus binding sites in the EAAT2 promoter. Moreover, astrocytic overexpression of REST attenuates Mn-induced reduction in EAAT2 expression, leading to attenuation of glutamate-induced neurotoxicity in the astrocyte–neuron coculture system. Our findings demonstrate that astrocytic REST plays a critical role in protection against Mn-induced neurotoxicity by attenuating Mn-induced EAAT2 repression and the ensuing excitotoxic dopaminergic neuronal injury. This indicates that astrocytic REST could be a potential molecular target for the treatment of Mn toxicity and other neurological disorders associated with EAAT2 dysregulation.
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Affiliation(s)
- Edward Pajarillo
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Alexis Digman
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Ivan Nyarko-Danquah
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Deok-Soo Son
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee, USA
| | - Karam F A Soliman
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA; Laboratory of Molecular Nutrition of the Institute for Personalized Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Eunsook Lee
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA.
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6
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Li X, Wang W, Yan J, Zeng F. Glutamic Acid Transporters: Targets for Neuroprotective Therapies in Parkinson's Disease. Front Neurosci 2021; 15:678154. [PMID: 34220434 PMCID: PMC8242205 DOI: 10.3389/fnins.2021.678154] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/07/2021] [Indexed: 12/21/2022] Open
Abstract
Parkinson's disease (PD) is a common neurodegenerative disease in middle-aged and elderly individuals. At present, no effective drug has been developed to treat PD. Although a variety of drugs exist for the symptomatic treatment of PD, they all have strong side effects. Most studies on PD mainly focus on dopaminergic neurons. This review highlights the function of glutamic acid transporters (GLTs), including excitatory amino acid transporters (EAATs) and vesicular glutamate transporters (VGLUTs), during the development of PD. In addition, using bioinformatics, we compared the expression of different types of glutamate transporter genes in the cingulate gyrus of PD patients and healthy controls. More importantly, we suggest that the functional roles of glutamate transporters may prove beneficial in the treatment of PD. In summary, VGLUTs and EAATs may be potential targets in the treatment of PD. VGLUTs and EAATs can be used as clinical drug targets to achieve better efficacy. Through this review article, we hope to enable future researchers to improve the condition of PD patients.
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Affiliation(s)
- Xiang Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou, China
| | - Wenjun Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou, China.,Institute for Cancer Medicine and School of Basic Medical Sciences, Southwest Medical University, Luzhou, China
| | - Jianghong Yan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou, China
| | - Fancai Zeng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou, China
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7
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Wang J, Wang F, Mai D, Qu S. Molecular Mechanisms of Glutamate Toxicity in Parkinson's Disease. Front Neurosci 2020; 14:585584. [PMID: 33324150 PMCID: PMC7725716 DOI: 10.3389/fnins.2020.585584] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/28/2020] [Indexed: 01/07/2023] Open
Abstract
Parkinson’s disease (PD) is a common neurodegenerative disease, the pathological features of which include the presence of Lewy bodies and the neurodegeneration of dopaminergic neurons in the substantia nigra pars compacta. However, until recently, research on the pathogenesis and treatment of PD have progressed slowly. Glutamate and dopamine are both important central neurotransmitters in mammals. A lack of enzymatic decomposition of extracellular glutamate results in glutamate accumulating at synapses, which is mainly absorbed by excitatory amino acid transporters (EAATs). Glutamate exerts its physiological effects by binding to and activating ligand-gated ion channels [ionotropic glutamate receptors (iGluRs)] and a class of G-protein-coupled receptors [metabotropic glutamate receptors (mGluRs)]. Timely clearance of glutamate from the synaptic cleft is necessary because high levels of extracellular glutamate overactivate glutamate receptors, resulting in excitotoxic effects in the central nervous system. Additionally, increased concentrations of extracellular glutamate inhibit cystine uptake, leading to glutathione depletion and oxidative glutamate toxicity. Studies have shown that oxidative glutamate toxicity in neurons lacking functional N-methyl-D-aspartate (NMDA) receptors may represent a component of the cellular death pathway induced by excitotoxicity. The association between inflammation and excitotoxicity (i.e., immunoexcitotoxicity) has received increased attention in recent years. Glial activation induces neuroinflammation and can stimulate excessive release of glutamate, which can induce excitotoxicity and, additionally, further exacerbate neuroinflammation. Glutamate, as an important central neurotransmitter, is closely related to the occurrence and development of PD. In this review, we discuss recent progress on elucidating glutamate as a relevant neurotransmitter in PD. Additionally, we summarize the relationship and commonality among glutamate excitotoxicity, oxidative toxicity, and immunoexcitotoxicity in order to posit a holistic view and molecular mechanism of glutamate toxicity in PD.
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Affiliation(s)
- Ji Wang
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China.,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China
| | - Fushun Wang
- Institute of Brain and Psychological Science, Sichuan Normal University, Chengdu, China.,Department of Neurosurgery, Baylor Scott & White Health, Temple, TX, United States
| | - Dongmei Mai
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China.,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China
| | - Shaogang Qu
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China.,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China
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8
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Pajarillo E, Johnson J, Rizor A, Nyarko-Danquah I, Adinew G, Bornhorst J, Stiboller M, Schwerdtle T, Son DS, Aschner M, Lee E. Astrocyte-specific deletion of the transcription factor Yin Yang 1 in murine substantia nigra mitigates manganese-induced dopaminergic neurotoxicity. J Biol Chem 2020; 295:15662-15676. [PMID: 32893191 PMCID: PMC7667968 DOI: 10.1074/jbc.ra120.015552] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/02/2020] [Indexed: 12/11/2022] Open
Abstract
Manganese (Mn)-induced neurotoxicity resembles Parkinson's disease (PD), but the mechanisms underpinning its effects remain unknown. Mn dysregulates astrocytic glutamate transporters, GLT-1 and GLAST, and dopaminergic function, including tyrosine hydroxylase (TH). Our previous in vitro studies have shown that Mn repressed GLAST and GLT-1 via activation of transcription factor Yin Yang 1 (YY1). Here, we investigated if in vivo astrocytic YY1 deletion mitigates Mn-induced dopaminergic neurotoxicity, attenuating Mn-induced reduction in GLAST/GLT-1 expression in murine substantia nigra (SN). AAV5-GFAP-Cre-GFP particles were infused into the SN of 8-week-old YY1 flox/flox mice to generate a region-specific astrocytic YY1 conditional knockout (cKO) mouse model. 3 weeks after adeno-associated viral (AAV) infusion, mice were exposed to 330 μg of Mn (MnCl2 30 mg/kg, intranasal instillation, daily) for 3 weeks. After Mn exposure, motor functions were determined in open-field and rotarod tests, followed by Western blotting, quantitative PCR, and immunohistochemistry to assess YY1, TH, GLAST, and GLT-1 levels. Infusion of AAV5-GFAP-Cre-GFP vectors into the SN resulted in region-specific astrocytic YY1 deletion and attenuation of Mn-induced impairment of motor functions, reduction of TH-expressing cells in SN, and TH mRNA/protein levels in midbrain/striatum. Astrocytic YY1 deletion also attenuated the Mn-induced decrease in GLAST/GLT-1 mRNA/protein levels in midbrain. Moreover, YY1 deletion abrogated its interaction with histone deacetylases in astrocytes. These results indicate that astrocytic YY1 plays a critical role in Mn-induced neurotoxicity in vivo, at least in part, by reducing astrocytic GLAST/GLT-1. Thus, YY1 might be a potential target for treatment of Mn toxicity and other neurological disorders associated with dysregulation of GLAST/GLT-1.
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Affiliation(s)
- Edward Pajarillo
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - James Johnson
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Asha Rizor
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Ivan Nyarko-Danquah
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Getinet Adinew
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Julia Bornhorst
- Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - Michael Stiboller
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Tania Schwerdtle
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Deok-Soo Son
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine Bronx, New York, New York, USA
| | - Eunsook Lee
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA.
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9
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Sheng L, Stewart T, Yang D, Thorland E, Soltys D, Aro P, Khrisat T, Xie Z, Li N, Liu Z, Tian C, Bercow M, Matsumoto J, Zabetian CP, Peskind E, Quinn JF, Shi M, Zhang J. Erythrocytic α-synuclein contained in microvesicles regulates astrocytic glutamate homeostasis: a new perspective on Parkinson's disease pathogenesis. Acta Neuropathol Commun 2020; 8:102. [PMID: 32641150 PMCID: PMC7346449 DOI: 10.1186/s40478-020-00983-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/29/2020] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease is a neurodegenerative disorder characterized by the transmission and accumulation of toxic species of α-synuclein (α-syn). Extracellular vesicles (EVs) are believed to play a vital role in the spread of toxic α-syn species. Recently, peripheral α-syn pathology has been investigated, but little attention has been devoted to erythrocytes, which contain abundant α-syn. In this study, we first demonstrated that erythrocyte-derived EVs isolated from Parkinson's disease patients carried elevated levels of oligomeric α-syn, compared to those from healthy controls. Moreover, human erythrocyte-derived EVs, when injected into peripheral blood in a mouse model of Parkinson's disease, were found to readily cross the blood-brain barrier (BBB). These EVs accumulated in astrocyte endfeet, a component of the BBB, where they impaired glutamate uptake, likely via interaction between excitatory amino acid transporter 2 (EAAT2) and oligomeric α-syn. These data suggest that erythrocyte-derived EVs and the oligomeric α-syn carried in them may play critical roles in the progression or even initiation of Parkinson's disease. Additionally, the mechanisms involved are attributable at least in part to dysfunction of astrocytes induced by these EVs. These observations provide new insight into the understanding of the mechanisms involved in Parkinson's disease.
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Affiliation(s)
- Lifu Sheng
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Tessandra Stewart
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Dishun Yang
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
- Department of Pathology, Peking University Health Science Centre and Third Hospital, Beijing, China
| | - Eric Thorland
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - David Soltys
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Patrick Aro
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Tarek Khrisat
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Zhiying Xie
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Na Li
- Department of Pathology, Peking University Health Science Centre and Third Hospital, Beijing, China
| | - Zongran Liu
- Department of Pathology, Peking University Health Science Centre and Third Hospital, Beijing, China
| | - Chen Tian
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Matthew Bercow
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Junichi Matsumoto
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Cyrus P Zabetian
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Elaine Peskind
- Mental Illness Research Education and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Joseph F Quinn
- Department of Neurology, Oregon Health and Science University, Portland, OR, USA
| | - Min Shi
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA.
| | - Jing Zhang
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA.
- Department of Pathology, the First Affiliated Hospital and School of Medicine, Zhejiang University, Hangzhou, 310003, China.
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10
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Gait Deficits and Loss of Striatal Tyrosine Hydroxlase/Trk-B are Restored Following 7,8-Dihydroxyflavone Treatment in a Progressive MPTP Mouse Model of Parkinson’s Disease. Neuroscience 2020; 433:53-71. [DOI: 10.1016/j.neuroscience.2020.02.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 12/13/2022]
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11
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Alam MA, Datta PK. Epigenetic Regulation of Excitatory Amino Acid Transporter 2 in Neurological Disorders. Front Pharmacol 2019; 10:1510. [PMID: 31920679 PMCID: PMC6927272 DOI: 10.3389/fphar.2019.01510] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/21/2019] [Indexed: 12/14/2022] Open
Abstract
Excitatory amino acid transporter 2 (EAAT2) is the predominant astrocyte glutamate transporter involved in the reuptake of the majority of the synaptic glutamate in the mammalian central nervous system (CNS). Gene expression can be altered without changing DNA sequences through epigenetic mechanisms. Mechanisms of epigenetic regulation, include DNA methylation, post-translational modifications of histones, chromatin remodeling, and small non-coding RNAs. This review is focused on neurological disorders, such as glioblastoma multiforme (GBM), Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), bipolar disorder (BD), and neuroHIV where there is evidence that epigenetics plays a role in the reduction of EAAT2 expression. The emerging field of pharmaco-epigenetics provides a novel avenue for epigenetics-based drug therapy. This review highlights findings on the role of epigenetics in the regulation of EAAT2 in different neurological disorders and discusses the current pharmacological approaches used and the potential use of novel therapeutic approaches to induce EAAT2 expression in neurological disorders using CRISPR/Cas9 technology.
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Affiliation(s)
- Mohammad Afaque Alam
- Department of Neuroscience, Center for Comprehensive NeuroAIDS, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Prasun K Datta
- Department of Neuroscience, Center for Comprehensive NeuroAIDS, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
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12
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Churchill MJ, Cantu MA, Kasanga EA, Moore C, Salvatore MF, Meshul CK. Glatiramer Acetate Reverses Motor Dysfunction and the Decrease in Tyrosine Hydroxylase Levels in a Mouse Model of Parkinson's Disease. Neuroscience 2019; 414:8-27. [PMID: 31220543 DOI: 10.1016/j.neuroscience.2019.06.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 12/13/2022]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease and there are no effective treatments that either slow or reverse the degeneration of the dopamine (DA) pathway. Using a 4-week progressive MPTP (1-methyl-1,2,3,6-tetrahydropyridine) neurotoxin model of PD, which is characterized by neuroinflammation, loss of nigrostriatal DA, and motor dysfunction, as seen in patients with PD, we tested whether post-MPTP treatment with glatiramer acetate (GA), an immunomodulatory drug, could reverse these changes. GA restored the grip dysfunction and gait abnormalities that were evident in the MPTP treated group. The reversal of the motor dysfunction was attributable to the substantial recovery in tyrosine hydroxylase (TH) protein expression in the striatum. Within the substantia nigra pars compacta, surface cell count analysis showed a slight increase in TH+ cells following GA treatment in the MPTP group, which was not statistically different from the vehicle (VEH) group. This was associated with the recovery of BDNF (brain derived neurotrophic factor) protein levels and a reduction in the microglial marker, IBA1, protein expression within the midbrain. Alpha synuclein (syn-1) levels within the midbrain and striatum were decreased following MPTP, while GA facilitated recovery to VEH levels in the striatum in the MPTP group. Although DA tissue analysis revealed no significant increase in striatal DA or 3,4-Dihydroxyphenylacetic acid levels (DOPAC) in the MPTP group treated with GA, DA turnover (DOPAC/DA) recovered back to VEH levels following GA treatment. GA treatment effectively reversed clinical (motor dysfunction) and pathology (TH, IBA1, BDNF expression) of PD in a murine model.
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Affiliation(s)
| | - Mark A Cantu
- Institute for Healthy Aging and Center for Neuroscience Discovery, University of North Texas Science Center, Fort Worth, TX, USA
| | - Ella A Kasanga
- Institute for Healthy Aging and Center for Neuroscience Discovery, University of North Texas Science Center, Fort Worth, TX, USA
| | - Cindy Moore
- Research Services, VA Medical Center/Portland, OR
| | - Michael F Salvatore
- Institute for Healthy Aging and Center for Neuroscience Discovery, University of North Texas Science Center, Fort Worth, TX, USA
| | - Charles K Meshul
- Research Services, VA Medical Center/Portland, OR; Department of Behavioral Neuroscience, Oregon Heath & Science University, Portland OR 97239; Department of Pathology, Oregon Health & Science University, Portland OR 97239
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13
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Identification of metabolite biomarkers for L-DOPA-induced dyskinesia in a rat model of Parkinson's disease by metabolomic technology. Behav Brain Res 2018; 347:175-183. [PMID: 29551735 DOI: 10.1016/j.bbr.2018.03.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 03/02/2018] [Accepted: 03/13/2018] [Indexed: 02/07/2023]
Abstract
L-DOPA-induced dyskinesia (LID) is a frequent complication of chronic L-DOPA therapy in the clinical treatment of Parkinson's disease (PD). The pathogenesis of LID involves complex molecular mechanisms in the striatum. Metabolomics can shed light on striatal metabolic alterations in LID. In the present study, we compared metabolomics profiles of striatum tissue from Parkinsonian rats with or without dyskinetic symptoms after chronic L-DOPA administration. A liquid chromatography-mass spectrometry based global metabolomics method combined with multivariate statistical analyses were used to detect candidate metabolites associated with LID. 36 dysregulated metabolites in the striatum of LID rats, including anandamide, 2-arachidonoylglycerol, adenosine, glutamate and sphingosine1-phosphate were identified. Furthermore, IMPaLA metabolite set analysis software was used to identify differentially regulated metabolic pathways. The results showed that the metabolic pathways of "Retrograde endocannabinoid signaling", "Phospholipase D signaling pathway", "Glycerophospholipid metabolism" and "Sphingolipid signaling", etc. were dysregulated in LID rats compared to non-LID controls. Moreover, integrated pathway analysis based on results from the present metabolomics and our previous gene expression data in LID rats further demonstrates that aberrant "Retrograde endocannabinoid signaling" pathway might be involved in the development of LID. The present results provide a new profile for the understanding of the pathological mechanism of LID.
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14
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Chotibut T, Meadows S, Kasanga E, McInnis T, Cantu MA, Bishop C, Salvatore MF. Ceftriaxone reduces L-dopa-induced dyskinesia severity in 6-hydroxydopamine parkinson's disease model. Mov Disord 2017; 32:1547-1556. [PMID: 28631864 PMCID: PMC5681381 DOI: 10.1002/mds.27077] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 05/15/2017] [Accepted: 05/26/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Increased extracellular glutamate may contribute to l-dopa induced dyskinesia, a debilitating side effect faced by Parkinson's disease patients 5 to 10 years after l-dopa treatment. Therapeutic strategies targeting postsynaptic glutamate receptors to mitigate dyskinesia may have limited success because of significant side effects. Increasing glutamate uptake may be another approach to attenuate excess glutamatergic neurotransmission to mitigate dyskinesia severity or prolong the time prior to onset. Initiation of a ceftriaxone regimen at the time of nigrostriatal lesion can attenuate tyrosine hydroxylase loss in conjunction with increased glutamate uptake and glutamate transporter GLT-1 expression in a rat 6-hydroxydopamine model. In this article, we examined if a ceftriaxone regimen initiated 1 week after nigrostriatal lesion, but prior to l-dopa, could reduce l-dopa-induced dyskinesia in an established dyskinesia model. METHODS Ceftriaxone (200 mg/kg, intraperitoneal, once daily, 7 consecutive days) was initiated 7 days post-6-hydroxydopamine lesion (days 7-13) and continued every other week (days 21-27, 35-39) until the end of the study (day 39 postlesion, 20 days of l-dopa). RESULTS Ceftriaxone significantly reduced abnormal involuntary movements at 5 time points examined during chronic l-dopa treatment. Partial recovery of motor impairment from nigrostriatal lesion by l-dopa was unaffected by ceftriaxone. The ceftriaxone-treated l-dopa group had significantly increased striatal GLT-1 expression and glutamate uptake. Striatal tyrosine hydroxylase loss in this group was not significantly different when compared with the l-dopa alone group. CONCLUSIONS Initiation of ceftriaxone after nigrostriatal lesion, but prior to and during l-dopa, may reduce dyskinesia severity without affecting l-dopa efficacy or the reduction of striatal tyrosine hydroxylase loss. © 2017 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Tanya Chotibut
- Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130
| | - Samantha Meadows
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000
| | - Ella Kasanga
- Institute for Healthy Aging & Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie, Fort Worth, TX 76107
| | - Tamara McInnis
- Institute for Healthy Aging & Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie, Fort Worth, TX 76107
| | - Mark A. Cantu
- Institute for Healthy Aging & Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie, Fort Worth, TX 76107
| | - Christopher Bishop
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000
| | - Michael F. Salvatore
- Institute for Healthy Aging & Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie, Fort Worth, TX 76107
- Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130
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15
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Exercise in an animal model of Parkinson's disease: Motor recovery but not restoration of the nigrostriatal pathway. Neuroscience 2017; 359:224-247. [PMID: 28754312 DOI: 10.1016/j.neuroscience.2017.07.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/11/2017] [Accepted: 07/13/2017] [Indexed: 11/23/2022]
Abstract
Many clinical studies have reported on the benefits of exercise therapy in patients with Parkinson's disease (PD). Exercise cannot stop the progression of PD or facilitate the recovery of dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) (Bega et al., 2014). To tease apart this paradox, we utilized a progressive MPTP (1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine) mouse model in which we initiated 4weeks of treadmill exercise after the completion of toxin administration (i.e., restoration). We found in our MPTP/exercise (MPTP+EX) group several measures of gait function that recovered compared to the MPTP only group. Although there was a small recovery of tyrosine hydroxylase (TH) positive DA neurons in the SNpc and terminals in the striatum, this increase was not statistically significant. These small changes in TH could not explain the improvement of motor function. The MPTP group had a significant 170% increase in the glycosylated/non-glycosylated dopamine transporter (DAT) and a 200% increase in microglial marker, IBA-1, in the striatum. The MPTP+EX group showed a nearly full recovery of these markers back to the vehicle levels. There was an increase in GLT-1 levels in the striatum due to exercise, with no change in striatal BDNF protein expression. Our data suggest that motor recovery was not prompted by any significant restoration of DA neurons or terminals, but rather the recovery of DAT and dampening the inflammatory response. Although exercise does not promote recovery of nigrostriatal DA, it should be used in conjunction with pharmaceutical methods for controlling PD symptoms.
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16
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Bentea E, Moore C, Deneyer L, Verbruggen L, Churchill MJ, Hood RL, Meshul CK, Massie A. Plastic changes at corticostriatal synapses predict improved motor function in a partial lesion model of Parkinson’s disease. Brain Res Bull 2017; 130:257-267. [DOI: 10.1016/j.brainresbull.2017.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/16/2017] [Indexed: 12/15/2022]
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17
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Bagga P, Crescenzi R, Krishnamoorthy G, Verma G, Nanga RPR, Reddy D, Greenberg J, Detre JA, Hariharan H, Reddy R. Mapping the alterations in glutamate with GluCEST MRI in a mouse model of dopamine deficiency. J Neurochem 2016; 139:432-439. [PMID: 27529288 DOI: 10.1111/jnc.13771] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 06/21/2016] [Accepted: 08/05/2016] [Indexed: 11/30/2022]
Abstract
Glutamate chemical exchange saturation transfer (GluCEST) MRI was used to measure metabolic changes in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) by mapping regional cerebral glutamate. The GluCEST contrast following MPTP treatment was correlated with 1 H-MR spectroscopy, motor function, and immunohistochemical measures. The GluCEST contrast was found to be significantly higher in the striatum and motor cortex of mice treated with MPTP than in controls (p < 0.001), which was confirmed by localized 1 H-MR spectroscopy. Elevated striatal GluCEST was positively associated with local astrogliosis measured by immunohistochemistry for glial fibrillary acidic protein. Additionally, a negative correlation was found between motor function, measured by the four-limb grip strength test, and GluCEST of the striatum (R = -0.705, p < 0.001) and the motor cortex (R = -0.617, p < 0.01), suggesting a role of elevated glutamate in the abnormal cerebral motor function regulation. The GluCEST contrast and glial fibrillary acidic protein immunostaining were unaltered in the thalamus indicating glutamate elevation was localized to the striatum and the motor cortex. These findings suggest that in addition to measuring spatial changes in glutamate, GluCEST may serve as an in vivo biomarker of metabolic and functional changes that may be applied to the assessment of a broad range of neuropathologies. Read the Editorial Highlight for this article on page 346.
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Affiliation(s)
- Puneet Bagga
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rachelle Crescenzi
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Guruprasad Krishnamoorthy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Gaurav Verma
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Damodar Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joel Greenberg
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - John A Detre
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
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18
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Kim JM, Cha SH, Choi YR, Jou I, Joe EH, Park SM. DJ-1 deficiency impairs glutamate uptake into astrocytes via the regulation of flotillin-1 and caveolin-1 expression. Sci Rep 2016; 6:28823. [PMID: 27346864 PMCID: PMC4922019 DOI: 10.1038/srep28823] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 06/10/2016] [Indexed: 12/12/2022] Open
Abstract
Parkinson’s disease (PD) is a common chronic and progressive neurodegenerative disorder. Although the cause of PD is still poorly understood, mutations in many genes including SNCA, parkin, PINK1, LRRK2, and DJ-1 have been identified in the familial forms of PD. It was recently proposed that alterations in lipid rafts may cause the neurodegeneration shown in PD. Here, we observe that DJ-1 deficiency decreased the expression of flotillin-1 (flot-1) and caveolin-1 (cav-1), the main protein components of lipid rafts, in primary astrocytes and MEF cells. As a mechanism, DJ-1 regulated flot-1 stability by direct interaction, however, decreased cav-1 expression may not be a direct effect of DJ-1, but rather as a result of decreased flot-1 expression. Dysregulation of flot-1 and cav-1 by DJ-1 deficiency caused an alteration in the cellular cholesterol level, membrane fluidity, and alteration in lipid rafts-dependent endocytosis. Moreover, DJ-1 deficiency impaired glutamate uptake into astrocytes, a major function of astrocytes in the maintenance of CNS homeostasis, by altering EAAT2 expression. This study will be helpful to understand the role of DJ-1 in the pathogenesis of PD, and the modulation of lipid rafts through the regulation of flot-1 or cav-1 may be a novel therapeutic target for PD.
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Affiliation(s)
- Jin-Mo Kim
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Seon-Heui Cha
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Yu Ree Choi
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea.,Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Korea
| | - Ilo Jou
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea.,Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Korea
| | - Eun-Hye Joe
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea.,Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Korea
| | - Sang Myun Park
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea.,Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Korea
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19
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Recent Advance in the Relationship between Excitatory Amino Acid Transporters and Parkinson's Disease. Neural Plast 2016; 2016:8941327. [PMID: 26981287 PMCID: PMC4769779 DOI: 10.1155/2016/8941327] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/05/2016] [Accepted: 01/18/2016] [Indexed: 01/12/2023] Open
Abstract
Parkinson's disease (PD) is the most common movement disorder disease in the elderly and is characterized by degeneration of dopamine neurons and formation of Lewy bodies. Glutamate is the major excitatory neurotransmitter in the central nervous system (CNS). If glutamate is not removed promptly in the synaptic cleft, it will excessively stimulate the glutamate receptors and induce excitotoxic effects on the CNS. With lack of extracellular enzyme to decompose glutamate, glutamate uptake in the synaptic cleft is mainly achieved by the excitatory amino acid transporters (EAATs, also known as high-affinity glutamate transporters). Current studies have confirmed that decreased expression and function of EAATs appear in PD animal models. Moreover, single unilateral administration of EAATs inhibitor in the substantia nigra mimics several PD features and this is a solid evidence supporting that decreased EAATs contribute to the process of PD. Drugs or treatments promoting the expression and function of EAATs are shown to attenuate dopamine neurons death in the substantia nigra and striatum, ameliorate the behavior disorder, and improve cognitive abilities in PD animal models. EAATs are potential effective drug targets in treatment of PD and thus study of relationship between EAATs and PD has predominant medical significance currently.
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20
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Caravaggio F, Nakajima S, Plitman E, Gerretsen P, Chung JK, Iwata Y, Graff-Guerrero A. The effect of striatal dopamine depletion on striatal and cortical glutamate: A mini-review. Prog Neuropsychopharmacol Biol Psychiatry 2016; 65:49-53. [PMID: 26334687 PMCID: PMC5323253 DOI: 10.1016/j.pnpbp.2015.08.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 08/19/2015] [Accepted: 08/27/2015] [Indexed: 02/07/2023]
Abstract
Understanding the interplay between the neurotransmitters dopamine and glutamate in the striatum has become the highlight of several theories of neuropsychiatric illnesses, such as schizophrenia. Using in vivo brain imaging in humans, alterations in dopamine and glutamate concentrations have been observed in several neuropsychiatric disorders. However, it is unclear a priori how alterations in striatal dopamine should modulate glutamate concentrations in the basal ganglia. In this selective mini-review, we examine the consequence of reducing striatal dopamine functioning on glutamate concentrations in the striatum and cortex; regions of interest heavily examined in the human brain imaging studies. We examine the predictions of the classical model of the basal ganglia, and contrast it with findings in humans and animals. The review concludes that chronic dopamine depletion (>4months) produces decreases in striatal glutamate levels which are consistent with the classical model of the basal ganglia. However, acute alterations in striatal dopamine functioning, specifically at the D2 receptors, may produce opposite affects. This has important implications for models of the basal ganglia and theorizing about neurochemical alterations in neuropsychiatric diseases. Moreover, these findings may help guide a priori hypotheses for (1)H-MRS studies measuring glutamate changes given alterations in dopaminergic functioning in humans.
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Affiliation(s)
- Fernando Caravaggio
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 2374 Medical Sciences Building, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Shinichiro Nakajima
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Eric Plitman
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 2374 Medical Sciences Building, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Philip Gerretsen
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 2374 Medical Sciences Building, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Jun Ku Chung
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 2374 Medical Sciences Building, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Yusuke Iwata
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 2374 Medical Sciences Building, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Ariel Graff-Guerrero
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 2374 Medical Sciences Building, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario M5T 1R8, Canada.
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21
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Takahashi K, Foster JB, Lin CLG. Glutamate transporter EAAT2: regulation, function, and potential as a therapeutic target for neurological and psychiatric disease. Cell Mol Life Sci 2015; 72:3489-506. [PMID: 26033496 PMCID: PMC11113985 DOI: 10.1007/s00018-015-1937-8] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/22/2015] [Accepted: 05/26/2015] [Indexed: 12/12/2022]
Abstract
Glutamate is the predominant excitatory neurotransmitter in the central nervous system. Excitatory amino acid transporter 2 (EAAT2) is primarily responsible for clearance of extracellular glutamate to prevent neuronal excitotoxicity and hyperexcitability. EAAT2 plays a critical role in regulation of synaptic activity and plasticity. In addition, EAAT2 has been implicated in the pathogenesis of many central nervous system disorders. In this review, we summarize current understanding of EAAT2, including structure, pharmacology, physiology, and functions, as well as disease relevancy, such as in stroke, Parkinson's disease, epilepsy, amyotrophic lateral sclerosis, Alzheimer's disease, major depressive disorder, and addiction. A large number of studies have demonstrated that up-regulation of EAAT2 protein provides significant beneficial effects in many disease models suggesting EAAT2 activation is a promising therapeutic approach. Several EAAT2 activators have been identified. Further understanding of EAAT2 regulatory mechanisms could improve development of drug-like compounds that spatiotemporally regulate EAAT2.
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Affiliation(s)
- Kou Takahashi
- Department of Neuroscience, The Ohio State University, 333 West 10th Avenue, Columbus, OH 43210 USA
| | - Joshua B. Foster
- Department of Neuroscience, The Ohio State University, 333 West 10th Avenue, Columbus, OH 43210 USA
| | - Chien-Liang Glenn Lin
- Department of Neuroscience, The Ohio State University, 333 West 10th Avenue, Columbus, OH 43210 USA
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22
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Pflibsen L, Stang KA, Sconce MD, Wilson VB, Hood RL, Meshul CK, Mitchell SH. Executive function deficits and glutamatergic protein alterations in a progressive 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease. J Neurosci Res 2015; 93:1849-64. [PMID: 26332770 DOI: 10.1002/jnr.23638] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/20/2015] [Accepted: 08/06/2015] [Indexed: 12/11/2022]
Abstract
Changes in executive function are at the root of most cognitive problems associated with Parkinson's disease. Because dopaminergic treatment does not necessarily alleviate deficits in executive function, it has been hypothesized that dysfunction of neurotransmitters/systems other than dopamine (DA) may be associated with this decrease in cognitive function. We have reported decreases in motor function and dopaminergic/glutamatergic biomarkers in a progressive 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) Parkinson's mouse model. Assessment of executive function and dopaminergic/glutamatergic biomarkers within the limbic circuit has not previously been explored in our model. Our results show progressive behavioral decline in a cued response task (a rodent model for frontal cortex cognitive function) with increasing weekly doses of MPTP. Although within the dorsolateral (DL) striatum mice that had been given MPTP showed a 63% and 83% loss of tyrosine hydroxylase and dopamine transporter expression, respectively, there were no changes in the nucleus accumbens or medial prefrontal cortex (mPFC). Furthermore, dopamine-1 receptor and vesicular glutamate transporter (VGLUT)-1 expression increased in the mPFC following DA loss. There were significant MPTP-induced decreases and increases in VGLUT-1 and VGLUT-2 expression, respectively, within the DL striatum. We propose that the behavioral decline following MPTP treatment may be associated with a change not only in cortical-cortical (VGLUT-1) glutamate function but also in striatal DA and glutamate (VGLUT-1/VGLUT-2) input.
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Affiliation(s)
- Lacey Pflibsen
- Research Services, VA Medical Center/Portland, Portland, Oregon
| | - Katherine A Stang
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon
| | | | - Vanessa B Wilson
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon
| | - Rebecca L Hood
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon
| | - Charles K Meshul
- Research Services, VA Medical Center/Portland, Portland, Oregon.,Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon.,Department of Pathology, Oregon Health and Science University, Portland, Oregon
| | - Suzanne H Mitchell
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon.,Department of Psychiatry, Oregon Health and Science University, Portland, Oregon
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23
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El Arfani A, Albertini G, Bentea E, Demuyser T, Van Eeckhaut A, Smolders I, Massie A. Alterations in the motor cortical and striatal glutamatergic system and D-serine levels in the bilateral 6-hydroxydopamine rat model for Parkinson's disease. Neurochem Int 2015; 88:88-96. [PMID: 26172319 DOI: 10.1016/j.neuint.2015.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 06/30/2015] [Accepted: 07/07/2015] [Indexed: 01/05/2023]
Abstract
Parkinson's disease (PD) is hallmarked by progressive degeneration of the substantia nigra pars compacta (SNc) neurons and is associated with aberrant glutamatergic activity. However, studies on the glutamatergic system in the motor cortex and striatum, two motor loop-related areas, are lacking in the clinically relevant bilateral SNc 6-hydroxydopamine (6-OHDA) rat model, and therefore led to the rationale behind the present investigations. Using Western blotting, the expression levels of the glial glutamate transporters, GLT-1 and GLAST, as well as xCT, the specific subunit of system xc(-), and the vesicular glutamate transporters, VGLUT1 and 2 were investigated at two different time points (1 week and 2 weeks) post-lesion. In addition, the total content of glutamate was measured. Moreover, the total D-serine levels were, to the best of our knowledge, studied for the first time in these two PD-related areas in the bilateral 6-OHDA rat model. In the motor cortex, no significant changes were observed in the different glutamate transporter expression levels in the bilaterally-lesioned rats. In the striatum, GLAST expression was significantly decreased at both time points whereas VGLUT1 and 2 expressions were significantly decreased 2 weeks after bilateral 6-OHDA lesion. Interestingly, bilateral 6-OHDA SNc lesion resulted in an enhancement of the total d-serine content in both motor cortex and striatum at 1 week post-lesion suggesting its possible involvement in the pathophysiology of PD. In conclusion, this study demonstrates disturbed glutamate and D-serine regulation in the bilateral SNc-lesioned brain which could contribute to the behavioral impairments in PD.
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Affiliation(s)
- Anissa El Arfani
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Eduard Bentea
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Thomas Demuyser
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Ann Van Eeckhaut
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
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24
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Sconce MD, Churchill MJ, Greene RE, Meshul CK. Intervention with exercise restores motor deficits but not nigrostriatal loss in a progressive MPTP mouse model of Parkinson's disease. Neuroscience 2015; 299:156-74. [PMID: 25943481 DOI: 10.1016/j.neuroscience.2015.04.069] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/28/2015] [Accepted: 04/28/2015] [Indexed: 12/25/2022]
Abstract
Many studies have investigated exercise therapy in Parkinson's disease (PD) and have shown benefits in improving motor deficits. However, exercise does not slow down the progression of the disease or induce the revival of lost nigrostriatal neurons. To examine the dichotomy of behavioral improvement without the slowing or recovery of dopaminergic cell or terminal loss, we tested exercise therapy in an intervention paradigm where voluntary running wheels were installed half-way through our progressive PD mouse model. In our model, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is administered over 4 weeks with increased doses each week (8, 16, 24, 32-kg/mg). We found that after 4 weeks of MPTP treatment, mice that volunteered to exercise had behavioral recovery in several measures despite the loss of 73% and 53% tyrosine hydroxylase (TH) within the dorsolateral (DL) striatum and the substantia nigra (SN), respectively which was equivalent to the loss seen in the mice that did not exercise but were also administered MPTP for 4 weeks. Mice treated with 4 weeks of MPTP showed a 41% loss of vesicular monoamine transporter II (VMAT2), a 71% increase in the ratio of glycosylated/non-glycosylated dopamine transporter (DAT), and significant increases in glutamate transporters including VGLUT1, GLT-1, and excitatory amino acid carrier 1. MPTP mice that exercised showed recovery of all these biomarkers back to the levels seen in the vehicle group and showed less inflammation compared to the mice treated with MPTP for 4 weeks. Even though we did not measure tissue dopamine (DA) concentration, our data suggest that exercise does not alleviate motor deficits by sparing nigrostriatal neurons, but perhaps by stabilizing the extraneuronal neurotransmitters, as evident by a recovery of DA and glutamate transporters. However, suppressing inflammation could be another mechanism of this locomotor recovery. Although exercise will not be a successful treatment alone, it could supplement other pharmaceutical approaches to PD therapy.
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Affiliation(s)
- M D Sconce
- Research Services, VA Medical Center/Portland, Mail Code: RD-29, Research Services, 3710 SW Veterans Hospital Road, Portland, OR 97239, United States
| | - M J Churchill
- Research Services, VA Medical Center/Portland, Mail Code: RD-29, Research Services, 3710 SW Veterans Hospital Road, Portland, OR 97239, United States
| | - R E Greene
- Research Services, VA Medical Center/Portland, Mail Code: RD-29, Research Services, 3710 SW Veterans Hospital Road, Portland, OR 97239, United States
| | - C K Meshul
- Research Services, VA Medical Center/Portland, Mail Code: RD-29, Research Services, 3710 SW Veterans Hospital Road, Portland, OR 97239, United States; Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States; Department of Pathology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States.
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Sconce M, Churchill M, Moore C, Meshul C. Intervention with 7,8-dihydroxyflavone blocks further striatal terminal loss and restores motor deficits in a progressive mouse model of Parkinson’s disease. Neuroscience 2015; 290:454-71. [DOI: 10.1016/j.neuroscience.2014.12.080] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/16/2014] [Accepted: 12/18/2014] [Indexed: 01/22/2023]
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Cote SR, Kuzhikandathil EV. Chronic levodopa treatment alters expression and function of dopamine D3 receptor in the MPTP/p mouse model of Parkinson's disease. Neurosci Lett 2014; 585:33-7. [PMID: 25445374 DOI: 10.1016/j.neulet.2014.11.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 11/11/2014] [Accepted: 11/15/2014] [Indexed: 01/25/2023]
Abstract
Chronic treatment with levodopa or antipsychotics results in manifestation of side-effects such as dyskinesia which correlates with changes in expression and function of receptors and signaling proteins. Previous studies have suggested a role for the dopamine D3 receptor in Parkinson's disease (PD) and tardive dyskinesia. Yet the expression and signaling function of D3 receptor in these disorders is not well understood. Here we tested the hypothesis that chronic levodopa treatment alters both expression and function of D3 receptors in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine plus probenecid (MPTP/p) mouse model of PD. drd3-EGFP reporter mice were injected biweekly with saline or MPTP and probenecid for a 5-week period. During the last two weeks of the 5-week period, the mice were administered saline or levodopa twice daily. Locomotor activity was measured during the treatment period. D3 receptor expression was determined by western blot analysis. D3 receptor signaling function was determined at tissue and single cell level by measuring the activation of D3 receptor-mitogen activated protein kinase (MAPK) pathway. The drd3-EGFP mice administered MPTP/p exhibited akinesia/bradykinesia. Expression of D3 receptor protein in the dorsal striatum specifically increased in the MPTP/p-treated mice administered levodopa. In the dorsal striatum of levodopa and MPTP/p-treated drd3-EGFP mice, administration of a D3 receptor-selective dose of agonist, PD128907, failed to activate D3 receptor-MAPK signaling. These results suggest that MPTP-induced lesion and chronic levodopa treatment alters D3 receptor expression and function in the dorsal striatum which could contribute to the development of dyskinesias and other motor side-effects.
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Affiliation(s)
- Samantha R Cote
- Department of Pharmacology and Physiology, Rutgers-New Jersey Medical School, 185 South Orange Avenue, MSB, I-647, Newark, NJ 07103, USA
| | - Eldo V Kuzhikandathil
- Department of Pharmacology and Physiology, Rutgers-New Jersey Medical School, 185 South Orange Avenue, MSB, I-647, Newark, NJ 07103, USA.
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Ferguson MC, Nayyar T, Ansah TA. Reverse microdialysis of a 5-HT2A receptor antagonist alters extracellular glutamate levels in the striatum of the MPTP mouse model of Parkinson's disease. Neurochem Int 2014; 71:36-46. [PMID: 24704796 DOI: 10.1016/j.neuint.2014.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 03/24/2014] [Accepted: 03/30/2014] [Indexed: 11/26/2022]
Abstract
Clinical observations have suggested that antagonism of 5-HT2A receptors may benefit patients with parkinsonian symptomatology. The mechanism of the antiparkinsonian effects of 5-HT2A receptor antagonists has not been fully elucidated. We have shown that the selective 5-HT2A receptor antagonist M100907 [R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenethyl)]-4-piperidinemethanol] improved motor impairments in mice treated with the parkinsonian neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In Parkinson's disease (PD) patients and animal models of parkinsonism dopamine denervation is associated with increased cortico-striatal glutamatergic transmission. We hypothesized that 5-HT2A receptor antagonists may exert their antiparkinsonian effects by decreasing striatal glutamate. Here, using in vivo microdialysis, we have shown an increased basal level of extracellular striatal glutamate when measured 3weeks after MPTP administration. The local administration of M100907 to the striatum significantly decreased striatal extracellular glutamate levels in MPTP-treated and saline treated mice. Basal extracellular serotonin (5-HT) levels were also elevated, whereas dopamine (DA) levels were significantly reduced in the striatum of MPTP-treated mice. Infusion of M100907 into the striatum produced no effect on dopamine or 5-HT levels. Local application of tetrodotoxin suppressed glutamate, 5-HT and DA concentrations in striatal dialysates in the presence or absence of M100907. The striatal expression of the glutamate transporter GLT1 was unchanged. However, there was an upregulation of the expression of 5-HT2A receptors in the striatum of MPTP-treated animals. Our data provide further evidence of enhanced glutamatergic neurotransmission in parkinsonism and demonstrate that blocking 5-HT2A receptors in the striatum will normalize glutamatergic neurotransmission.
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Affiliation(s)
- Marcus C Ferguson
- Department of Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, United States
| | - Tultul Nayyar
- Department of Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, United States
| | - Twum A Ansah
- Department of Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, United States.
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Nevalainen N, Lundblad M, Gerhardt GA, Strömberg I. Striatal glutamate release in L-DOPA-induced dyskinetic animals. PLoS One 2013; 8:e55706. [PMID: 23390548 PMCID: PMC3563586 DOI: 10.1371/journal.pone.0055706] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 12/28/2012] [Indexed: 11/18/2022] Open
Abstract
L-DOPA-induced dyskinesia is a common side effect developed after chronic treatment with 3,4-dihydroxyphenyl-l-alanine (l-DOPA) in Parkinson's disease. The biological mechanisms behind this side effect are not fully comprehended although involvement of dopaminergic, serotonergic, and glutamatergic systems has been suggested. The present study utilizes in vivo amperometry to investigate the impact from unilateral 6-hydroxydopamine lesions and l-DOPA (4 mg/kg, including benserazide 15 mg/kg) -induced dyskinetic behavior on striatal basal extracellular glutamate concentration and potassium-evoked glutamate release in urethane-anesthetized rats. Recordings were performed before and after local L-DOPA application in the striatum. In addition, effects from the 5-HT(1A) receptor agonist (2R)-(+)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OHDPAT; 1 mg/kg) was assessed on glutamate release and on dyskinetic behavior. The results revealed a bilateral ≈ 30% reduction of basal extracellular glutamate concentration and attenuated potassium-evoked glutamate release after a unilateral dopamine-depletion in L-DOPA naïve animals. In dyskinetic subjects, basal glutamate concentration was comparable to normal controls, although potassium-evoked glutamate release was reduced to similar levels as in drug naïve dopamine-lesioned animals. Furthermore, acute striatal L-DOPA administration attenuated glutamate release in all groups, except in the dopamine-lesioned striatum of dyskinetic animals. Co-administration of 8-OHDPAT and L-DOPA decreased dyskinesia in dopamine-lesioned animals, but did not affect potassium-evoked glutamate release, which was seen in normal animals. These findings indicate altered glutamate transmission upon dopamine-depletion and dyskinesia.
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Affiliation(s)
| | - Martin Lundblad
- Basal Ganglia Pathophysiology Unit, Neuroscience Section, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Greg A. Gerhardt
- Anatomy, Neurobiology, and Neurology, University of Kentucky Medical Center, Lexington, Kentucky, United States of America
| | - Ingrid Strömberg
- Integrative Medical Biology, Umeå University, Umeå, Sweden
- * E-mail:
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Lin CLG, Kong Q, Cuny GD, Glicksman MA. Glutamate transporter EAAT2: a new target for the treatment of neurodegenerative diseases. Future Med Chem 2012; 4:1689-700. [PMID: 22924507 PMCID: PMC3580837 DOI: 10.4155/fmc.12.122] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Glutamate is the primary excitatory amino acid neurotransmitter in the CNS. The concentration of glutamate in the synaptic cleft is tightly controlled by interplay between glutamate release and glutamate clearance. Abnormal glutamate release and/or dysfunction of glutamate clearance can cause overstimulation of glutamate receptors and result in neuronal injury known as excitotoxicity. The glial glutamate transporter EAAT2 plays a major role in glutamate clearance. Dysfunction or reduced expression of EAAT2 has been documented in many neurodegenerative diseases. In addition, many studies in animal models of disease indicate that increased EAAT2 expression provides neuronal protection. Here, we summarize these studies and suggest that EAAT2 is a potential target for the prevention of excitotoxicity. EAAT2 can be upregulated by transcriptional or translational activation. We discuss current progress in the search for EAAT2 activators, which is a promising direction for the treatment of neurodegenerative diseases.
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Mao P, Meshul CK, Thuillier P, Goldberg NRS, Reddy PH. CART peptide is a potential endogenous antioxidant and preferentially localized in mitochondria. PLoS One 2012; 7:e29343. [PMID: 22235287 PMCID: PMC3250433 DOI: 10.1371/journal.pone.0029343] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 11/25/2011] [Indexed: 12/04/2022] Open
Abstract
The multifunctional neuropeptide Cocaine and Amphetamine Regulated Transcript (CART) is secreted from hypothalamus, pituitary, adrenal gland and pancreas. It also can be found in circulatory system. This feature suggests a general role for CART in different cells. In the present study, we demonstrate that CART protects mitochondrial DNA (mtDNA), cellular proteins and lipids against the oxidative action of hydrogen peroxide, a widely used oxidant. Using cis-parinaric acid as a sensitive reporting probe for peroxidation in membranes, and a lipid-soluble azo initiator of peroxyl radicals, 2,2'-azobis(2,4-dimethylvaleronitrile) we found that CART is an antioxidant. Furthermore, we found that CART localized to mitochondria in cultured cells and mouse brain neuronal cells. More importantly, pretreatment with CART by systemic injection protects against a mouse oxidative stress model, which mimics the main features of Parkinson's disease. Given the unique molecular structure and biological features of CART, we conclude that CART is an antioxidant peptide (or antioxidant hormone). We further propose that it may have strong therapeutic properties for human diseases in which oxidative stress is strongly involved such as Parkinson's disease.
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Affiliation(s)
- Peizhong Mao
- The Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America.
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Villalba RM, Smith Y. Neuroglial plasticity at striatal glutamatergic synapses in Parkinson's disease. Front Syst Neurosci 2011; 5:68. [PMID: 21897810 PMCID: PMC3159891 DOI: 10.3389/fnsys.2011.00068] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 08/02/2011] [Indexed: 01/08/2023] Open
Abstract
Striatal dopamine denervation is the pathological hallmark of Parkinson's disease (PD). Another major pathological change described in animal models and PD patients is a significant reduction in the density of dendritic spines on medium spiny striatal projection neurons. Simultaneously, the ultrastructural features of the neuronal synaptic elements at the remaining corticostriatal and thalamostriatal glutamatergic axo-spinous synapses undergo complex ultrastructural remodeling consistent with increased synaptic activity (Villalba and Smith, 2011). The concept of tripartite synapses (TS) was introduced a decade ago, according to which astrocytes process and exchange information with neuronal synaptic elements at glutamatergic synapses (Araque et al., 1999a). Although there has been compelling evidence that astrocytes are integral functional elements of tripartite glutamatergic synaptic complexes in the cerebral cortex and hippocampus, their exact functional role, degree of plasticity and preponderance in other CNS regions remain poorly understood. In this review, we discuss our recent findings showing that neuronal elements at cortical and thalamic glutamatergic synapses undergo significant plastic changes in the striatum of MPTP-treated parkinsonian monkeys. We also present new ultrastructural data that demonstrate a significant expansion of the astrocytic coverage of striatal TS synapses in the parkinsonian state, providing further evidence for ultrastructural compensatory changes that affect both neuronal and glial elements at TS. Together with our limited understanding of the mechanisms by which astrocytes respond to changes in neuronal activity and extracellular transmitter homeostasis, the role of both neuronal and glial components of excitatory synapses must be considered, if one hopes to take advantage of glia–neuronal communication knowledge to better understand the pathophysiology of striatal processing in parkinsonism, and develop new PD therapeutics.
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Affiliation(s)
- Rosa M Villalba
- Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University Atlanta, GA, USA
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Darvesh AS, Carroll RT, Geldenhuys WJ, Gudelsky GA, Klein J, Meshul CK, Van der Schyf CJ. In vivo brain microdialysis: advances in neuropsychopharmacology and drug discovery. Expert Opin Drug Discov 2011; 6:109-127. [PMID: 21532928 PMCID: PMC3083031 DOI: 10.1517/17460441.2011.547189] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION: Microdialysis is an important in vivo sampling technique, useful in the assay of extracellular tissue fluid. The technique has both pre-clinical and clinical applications but is most widely used in neuroscience. The in vivo microdialysis technique allows measurement of neurotransmitters such as acetycholine (ACh), the biogenic amines including dopamine (DA), norepinephrine (NE) and serotonin (5-HT), amino acids such as glutamate (Glu) and gamma aminobutyric acid (GABA), as well as the metabolites of the aforementioned neurotransmitters, and neuropeptides in neuronal extracellular fluid in discrete brain regions of laboratory animals such as rodents and non-human primates. AREAS COVERED: In this review we present a brief overview of the principles and procedures related to in vivo microdialysis and detail the use of this technique in the pre-clinical measurement of drugs designed to be used in the treatment of chemical addiction, neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and as well as psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) and schizophrenia. This review offers insight into the tremendous utility and versatility of this technique in pursuing neuropharmacological investigations as well its significant potential in rational drug discovery. EXPERT OPINION: In vivo microdialysis is an extremely versatile technique, routinely used in the neuropharmacological investigation of drugs used for the treatment of neurological disorders. This technique has been a boon in the elucidation of the neurochemical profile and mechanism of action of several classes of drugs especially their effects on neurotransmitter systems. The exploitation and development of this technique for drug discovery in the near future will enable investigational new drug candidates to be rapidly moved into the clinical trial stages and to market thus providing new successful therapies for neurological diseases that are currently in demand.
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Affiliation(s)
- Altaf S. Darvesh
- Pharmaceutical Sciences-Neurotherapeutics Focus Group, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, OH 44272, USA
- Psychiatry, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, OH 44272, USA
| | - Richard T. Carroll
- Pharmaceutical Sciences-Neurotherapeutics Focus Group, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, OH 44272, USA
| | - Werner J. Geldenhuys
- Pharmaceutical Sciences-Neurotherapeutics Focus Group, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, OH 44272, USA
| | - Gary A. Gudelsky
- Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Jochen Klein
- Chemistry, Biochemistry, Pharmacy, Johann Wolfgang Goethe University of Frankfurt, Frankfurt, D-60438, Germany
| | - Charles K. Meshul
- Behavioral Neuroscience, Pathology, School of Medicine, Oregon Health and Science University, Portland, OR 97239, USA
- Portland Veterans Affairs Research Center, Portland, OR 97239, USA
| | - Cornelis J. Van der Schyf
- Pharmaceutical Sciences-Neurotherapeutics Focus Group, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, OH 44272, USA
- Neurobiology, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, OH 44272, USA
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Enriched environment promotes similar neuronal and behavioral recovery in a young and aged mouse model of Parkinson's disease. Neuroscience 2010; 172:443-52. [PMID: 20933577 DOI: 10.1016/j.neuroscience.2010.09.062] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 09/30/2010] [Indexed: 01/15/2023]
Abstract
Environmental enrichment has been shown to be neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease (PD). Because PD patients are not typically diagnosed until later neuropathological stages, the current study investigated the capacity of an enriched environment (EE) to stimulate restoration of neurons in the substantia nigra pars compacta (SNpc) and locomotor recovery after lesioning, as opposed to before. A low-dose chronic MPTP regimen was used to achieve a partial, less severe lesion of the nigrostriatal pathway not seen in acute MPTP models. Both young adult (10 weeks) and aged (12 months) C57BL/6J male mice were used to assess the effects of aging on recovery with EE intervention. After the first week of either MPTP (7 mg/kg/d in young; 5 mg/kg/d in aged) or saline injection, animals from both groups were housed in a standard environment (SE) or an EE for 3 weeks, with continued daily administration of MPTP. We are the first to report that following 3 weeks exposure to an EE, young and aged MPTP-lesioned mice showed a significant 53% and 52% restoration of tyrosine hydroxylase (TH)-labeled neurons in the SNpc, respectively. This increase in TH-labeled cells in the MPTP+EE group was correlated with recovery of free-standing rear (FSR) behavior in both age groups; however, improved locomotor control as measured by foot faults (FF) per total activity was only seen in the aged MPTP+EE group. Our data demonstrate that an EE promotes neurorestoration in TH protein expression in SNpc neurons as well as some locomotor recovery in both young and aged animals in this mouse model of PD.
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Massie A, Goursaud S, Schallier A, Vermoesen K, Meshul CK, Hermans E, Michotte Y. Time-dependent changes in GLT-1 functioning in striatum of hemi-Parkinson rats. Neurochem Int 2010; 57:572-8. [PMID: 20643175 DOI: 10.1016/j.neuint.2010.07.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 06/29/2010] [Accepted: 07/08/2010] [Indexed: 10/19/2022]
Abstract
Striatal dopamine loss in Parkinson's disease is accompanied by a dysregulation of corticostriatal glutamatergic neurotransmission. Within this study, we investigated striatal expression and activity of the glial high-affinity Na(+)/K(+)-dependent glutamate transporters, GLT-1 and GLAST, in the 6-hydroxydopamine hemi-Parkinson rat model at different time points after unilateral 6-hydroxydopamine injection into the medial forebrain bundle. Using semi-quantitative Western blotting and an ex vivo D-[(3)H]-aspartate uptake assay, we showed a time-dependent bilateral effect of unilateral 6-hydroxydopamine lesioning on the expression as well as activity of GLT-1. At 3 and 12 weeks post-lesion, striatal GLT-1 function was bilaterally upregulated whereas at 5 weeks there was no change. Even though our data do not allow a straightforward conclusion as for the role of glutamate transporters in the pathogenesis of the disease, they do clearly demonstrate a link between disturbed glutamatergic neurotransmission and glutamate transporter functioning in the striatum of a rat model for Parkinson's disease.
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Affiliation(s)
- Ann Massie
- Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Brussels, Belgium
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Chassain C, Bielicki G, Keller C, Renou JP, Durif F. Metabolic changes detected in vivo by 1H MRS in the MPTP-intoxicated mouse. NMR IN BIOMEDICINE 2010; 23:547-553. [PMID: 20661872 DOI: 10.1002/nbm.1504] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We used in vivo proton ((1)H) Magnetic Resonance Spectroscopy (MRS) to measure the levels of the main excitatory amino acid, glutamate (Glu) and also glutamine (Gln) and GABA in the striatum and cerebral cortex in the MPTP-intoxicated mouse, a model of dopaminergic denervation, before and after dopamine (DA) replacement. The study was performed at 9.4T on control mice (n = 8) and MPTP-intoxicated mice (n = 8). In vivo spectra were acquired in a voxel (8 microL) centered in the striatum, and in the cortex (4.6 microL). Three days after basal MRS acquisitions new spectra were acquired in the striatum and cortex, after levodopa (200 mg.kg(-1)). Glu, Gln and GABA concentrations obtained in the basal state were significantly increased in the striatum of MPTP-lesioned mice (Glu: 20.2 +/- 0.8 vs 11.4 +/- 0.9 mM, p < 0.001; Gln: 5.4 +/- 1.6 vs 2.0 +/- 0.6 mM, p < 0.05; GABA: 3.6 +/- 0.8 vs 1.6 +/- 0.2 mM, p < 0.05). Levodopa lowered metabolites concentrations in the striatum of MPTP-lesioned mice (Glu: 20.2 +/- 0.8 vs 11.2 +/- 0.4 mM (+ Ldopa), p < 0.001; Gln: 5.4 +/- 1.6 vs 1.6 +/- 0.4 mM (+ Ldopa), p < 0.05; GABA: 3.6 +/- 0.8 vs 1.7 +/- 0.4 mM (+ Ldopa), p < 0.01). Metabolite levels in the striatum of MPTP-intoxicated mice + levodopa were not significantly different from those in the striatum of controls. No change was found in the cortex after DA denervation and after DA replacement between the two animals groups. These results strongly support a predominant change in striatal Glu synaptic activity in the cortico-striatal pathway. Acute levodopa administration reverses the increase of metabolites in the striatum.
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Affiliation(s)
- Carine Chassain
- University Clermont 1, UFR Medicine, Clermont-Ferrand, France
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Meredith GE, Totterdell S, Beales M, Meshul CK. Impaired glutamate homeostasis and programmed cell death in a chronic MPTP mouse model of Parkinson's disease. Exp Neurol 2009; 219:334-40. [PMID: 19523952 DOI: 10.1016/j.expneurol.2009.06.005] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 05/31/2009] [Accepted: 06/04/2009] [Indexed: 01/22/2023]
Abstract
The pathogenesis of Parkinson's disease is not fully understood, but there is evidence that excitotoxic mechanisms contribute to the pathology. However, data supporting a role for excitotoxicity in the pathophysiology of the disease are controversial and sparse. The goal of this study was to determine whether changes in glutamate signaling and uptake contribute to the demise of dopaminergic neurons in the substantia nigra. Mice were treated chronically with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and probenecid or vehicle (probenecid or saline alone). Extracellular levels of glutamate in the substantia nigra were substantially increased, and there was an increase in the affinity, but no change in the velocity, of glutamate transport after MPTP/probenecid treatment compared to vehicle controls. In addition, the substantia nigra showed two types of programmed death, apoptosis (type I) and autophagic (type II) cell death. These data suggest that increased glutamate signaling could be an important mechanism for the death of dopaminergic neurons and trigger the induction of programmed cell death in the chronic MPTP/probenecid model.
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Affiliation(s)
- G E Meredith
- Department of Cellular and Molecular Pharmacology, Chicago Medical School, Rosalind Franklin University, 3333 Green Bay Road, North Chicago, IL 60064, USA.
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Effects of subthalamic nucleus lesions and stimulation upon glutamate levels in the dopamine-depleted rat striatum. Neuroreport 2009; 20:770-5. [DOI: 10.1097/wnr.0b013e32832ad556] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Fogal B, Hewett SJ. Interleukin-1beta: a bridge between inflammation and excitotoxicity? J Neurochem 2008; 106:1-23. [PMID: 18315560 DOI: 10.1111/j.1471-4159.2008.05315.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Interleukin-1 (IL-1) is a proinflammatory cytokine released by many cell types that acts in both an autocrine and/or paracrine fashion. While IL-1 is best described as an important mediator of the peripheral immune response during infection and inflammation, increasing evidence implicates IL-1 signaling in the pathogenesis of several neurological disorders. The biochemical pathway(s) by which this cytokine contributes to brain injury remain(s) largely unidentified. Herein, we review the evidence that demonstrates the contribution of IL-1beta to the pathogenesis of both acute and chronic neurological disorders. Further, we highlight data that leads us to propose IL-1beta as the missing mechanistic link between a potential beneficial inflammatory response and detrimental glutamate excitotoxicity.
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Affiliation(s)
- Birgit Fogal
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
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Hascup KN, Hascup ER, Pomerleau F, Huettl P, Gerhardt GA. Second-by-second measures of L-glutamate in the prefrontal cortex and striatum of freely moving mice. J Pharmacol Exp Ther 2008; 324:725-31. [PMID: 18024788 PMCID: PMC3404456 DOI: 10.1124/jpet.107.131698] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
l-Glutamate (Glu) is the main excitatory neurotransmitter in the mammalian central nervous system, and it is involved in most aspects of normal brain function, including cognition, memory and learning, plasticity, and motor movement. Although microdialysis techniques have been used to study Glu, the slow temporal resolution of the technique may be inadequate to properly examine tonic and phasic Glu. Thus, our laboratory has developed an enzyme-based microelectrode array (MEA) with fast response time and low detection limits for Glu. We have modified the MEA design to allow for reliable measures in the brain of awake, freely moving mice. In this study, we chronically implanted the MEA in prefrontal cortex (PFC) or striatum (Str) of awake, freely moving C57BL/6 mice. We successfully measured Glu levels 7 days postimplantation without loss of MEA sensitivity. In addition, we determined resting (tonic) Glu levels to be 3.3 microM in the PFC and 5.0 microM in the Str. Resting Glu levels were subjected to pharmacological manipulation with tetrodotoxin (TTX) and dl-threo-beta-hydroxyaspartate (THA). TTX significantly (p < 0.05) decreased resting Glu by 20%, whereas THA significantly (p < 0.05) increased resting Glu by 60%. Taken together, our data show that chronic recordings of tonic and phasic clearance of exogenously applied Glu can be carried out in awake mice for at least 7 days in vivo, allowing for longer term studies of Glu regulation.
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Affiliation(s)
- K N Hascup
- Department of Anatomy and Neurobiology, 306 Whitney-Hendrickson Facility, 800 Rose St., Lexington, KY 40536-0098, USA
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Aoyama K, Matsumura N, Watabe M, Nakaki T. Oxidative stress on EAAC1 is involved in MPTP-induced glutathione depletion and motor dysfunction. Eur J Neurosci 2007; 27:20-30. [DOI: 10.1111/j.1460-9568.2007.05979.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Gunzler SA, Shakil S, Carlson NE, Nutt JG, Meshul CK. Low doses of apomorphine transiently reduce locomotor activity in MPTP-treated mice. Neurosci Lett 2007; 428:64-7. [DOI: 10.1016/j.neulet.2007.09.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 09/20/2007] [Accepted: 09/25/2007] [Indexed: 10/25/2022]
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