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Wang X, Marmouzi I, Finnie PS, Støve SI, Bucher ML, Lipina TV, Ramsey AJ, Miller GW, Salahpour A. Tricyclic and tetracyclic antidepressants upregulate VMAT2 activity and rescue disease-causing VMAT2 variants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.09.561601. [PMID: 37873339 PMCID: PMC10592782 DOI: 10.1101/2023.10.09.561601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Vesicular monoamine transporter 2 (VMAT2) is an essential transporter that regulates brain monoamine transmission and is important for mood, cognition, motor activity, and stress regulation. However, VMAT2 remains underexplored as a pharmacological target. In this study, we report that tricyclic and tetracyclic antidepressants acutely inhibit, but persistently upregulate VMAT2 activity by promoting VMAT2 protein maturation. Importantly, the VMAT2 upregulation effect was greater in BE(2)-M17 cells that endogenously express VMAT2 as compared to a heterologous expression system (HEK293). The net sustained effect of tricyclics and tetracyclics is an upregulation of VMAT2 activity, despite their acute inhibitory effect. Furthermore, imipramine and mianserin, two representative compounds, also demonstrated rescue of nine VMAT2 variants that cause Brain Vesicular Monoamine Transport Disease (BVMTD). VMAT2 upregulation could be beneficial for disorders associated with reduced monoamine transmission, including mood disorders and BVMTD, a rare but often fatal condition caused by a lack of functional VMAT2. Our findings provide the first evidence that small molecules can upregulate VMAT2 and have potential therapeutic benefit for various neuropsychiatric conditions.
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Bucher ML, Barrett CW, Moon CJ, Mortimer AD, Burton EA, Greenamyre JT, Hastings TG. Acquired dysregulation of dopamine homeostasis reproduces features of Parkinson's disease. NPJ PARKINSONS DISEASE 2020; 6:34. [PMID: 33298952 PMCID: PMC7666186 DOI: 10.1038/s41531-020-00134-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 10/08/2020] [Indexed: 12/24/2022]
Abstract
The catecholamine neurotransmitter dopamine has the potential to act as an endogenous neurotoxin when its vesicular sequestration is dysregulated. Despite postmortem analyses from patients with Parkinson’s disease that demonstrate decreased vesicular sequestration of dopamine with a corresponding increase in dopamine metabolism, dopamine’s contribution to nigrostriatal dopaminergic degeneration in Parkinson’s disease has been debated. Here, we present a new in vivo model demonstrating the induction of Parkinson’s disease-associated pathogenic mechanisms of degeneration resulting from acquired dysregulation of dopamine sequestration in nigrostriatal dopaminergic neurons in adult rats. Utilizing adeno-associated virus (serotype 2), viral-mediated small-hairpin RNA interference of endogenous vesicular monoamine transporter 2 (VMAT2) expression resulted in a loss of VMAT2 protein expression in transduced dopaminergic cell bodies in the substantia nigra with a corresponding loss of VMAT2 protein within the striatal terminals. The loss of VMAT2 resulted in an accumulation of cytosolic dopamine and subsequent increased dopamine metabolism, deficits in dopamine-mediated behaviors, and degeneration of nigrostriatal dopaminergic neurons that was rescued through reintroduction of exogenous VMAT2, demonstrating that the toxicity was specific to the loss of VMAT2. Analysis of parkinsonian pathogenic mechanisms of degeneration identified oxidative damage, activation of Parkinson’s disease-associated kinase LRRK2, and the formation of aberrant α-synuclein. This model demonstrates that a progressive acquired loss of VMAT2 expression in adulthood is sufficient to induce Parkinson’s disease-associated pathogenic mechanisms of degeneration and provides a new model to further investigate the consequences of cytosolic dopamine.
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Affiliation(s)
- Meghan L Bucher
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Department of Neuroscience, University of Pittsburgh School of Arts and Sciences, Pittsburgh, PA, USA.,Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Caitlyn W Barrett
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Connor J Moon
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Department of Neuroscience, University of Pittsburgh School of Arts and Sciences, Pittsburgh, PA, USA
| | - Amanda D Mortimer
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Edward A Burton
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Geriatric Research, Education and Clinical Center, Pittsburgh VA Healthcare System, Pittsburgh, PA, USA
| | - J Timothy Greenamyre
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Teresa G Hastings
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA. .,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. .,Department of Neuroscience, University of Pittsburgh School of Arts and Sciences, Pittsburgh, PA, USA.
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Markos S, Failla MD, Ritter AC, Dixon CE, Conley YP, Ricker JH, Arenth PM, Juengst SB, Wagner AK. Genetic Variation in the Vesicular Monoamine Transporter: Preliminary Associations With Cognitive Outcomes After Severe Traumatic Brain Injury. J Head Trauma Rehabil 2018; 32:E24-E34. [PMID: 26828714 PMCID: PMC4967045 DOI: 10.1097/htr.0000000000000224] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Traumatic brain injury (TBI) frequently results in impaired cognition, a function that can be modulated by monoaminergic signaling. Genetic variation among monoaminergic genes may affect post-TBI cognitive performance. The vesicular monoamine transporter-2 (VMAT2) gene may be a novel source of genetic variation important for cognitive outcomes post-TBI given VMAT2's role in monoaminergic neurotransmission. OBJECTIVE To evaluate associations between VMAT2 variability and cognitive outcomes post-TBI. METHODS We evaluated 136 white adults with severe TBI for variation in VMAT2 using a tagging single nucleotide polymorphism (tSNP) approach (rs363223, rs363226, rs363251, and rs363341). We show genetic variation interacts with assessed cognitive impairment (cognitive composite [Comp-Cog] T-scores) to influence functional cognition (functional independence measure cognitive [FIM-Cog] subscale] 6 and 12 months postinjury. RESULTS Multivariate analyses at 6 months postinjury showed rs363226 genotype was associated with Comp-Cog (P = .040) and interacted with Comp-Cog to influence functional cognition (P < .001). G-homozygotes had the largest cognitive impairment, and their cognitive impairment had the greatest adverse effect on functional cognition. DISCUSSION We provide the first evidence that genetic variation within VMAT2 is associated with cognitive outcomes after TBI. Further work is needed to validate this finding and elucidate mechanisms by which genetic variation affects monoaminergic signaling, mediating differences in cognitive outcomes.
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Affiliation(s)
- Steven Markos
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh PA
| | - Michelle D. Failla
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh PA
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA
| | - Anne C Ritter
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh PA
| | - C. Edward Dixon
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh PA
- Center for Neuroscience, University of Pittsburgh
- Pittsburgh VA Healthcare System
- Department of Neurological Surgery, School of Medicine, University of Pittsburgh
| | - Yvette P. Conley
- Department of Human Genetics, University of Pittsburgh, School of Public Health, Pittsburgh, PA
- Health Promotion & Development, University of Pittsburgh, School of Nursing, Pittsburgh, PA
| | - Joseph H Ricker
- Department of Rehabilitation Medicine, New York University, School of Medicine, New York, NY
| | - Patricia M. Arenth
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh PA
| | - Shannon B. Juengst
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh PA
| | - Amy K. Wagner
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, School of Medicine, Pittsburgh PA
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA
- Center for Neuroscience, University of Pittsburgh
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA
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Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Agúndez JAG. Advances in understanding genomic markers and pharmacogenetics of Parkinson's disease. Expert Opin Drug Metab Toxicol 2016; 12:433-48. [PMID: 26910127 DOI: 10.1517/17425255.2016.1158250] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The inheritance pattern of Parkinson's disease (PD) is likely multifactorial (owing to the interplay of genetic predisposition and environmental factors). Many pharmacogenetic studies have tried to establish a possible role of candidate genes in PD risk. Several studies have focused on the influence of genes in the response to antiparkinsonian drugs and in the risk of developing side-effects of these drugs. AREAS COVERED This review presents an overview of current knowledge, with particular emphasis on the most recent advances, both in case-control association studies on the role of candidate genes in the risk for PD as well as pharmacogenetic studies on the role of genes in the development of side effects of antiparkinsonian drugs. The most reliable results should be derived from meta-analyses of case-control association studies on candidate genes involving large series of PD patients and controls, and from genome-wide association studies (GWAS). EXPERT OPINION Prospective studies of large samples involving several genes with a detailed history of exposure to environmental factors in the same cohort of subjects, should be useful to clarify the role of genes in the risk for PD. The results of studies on the role of genes in the development of side-effects of antiparkinsonian drugs should, at this stage, only be considered preliminary.
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Affiliation(s)
| | | | | | - José A G Agúndez
- b Department of Pharmacology , University of Extremadura , Cáceres , Spain
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